Logo

Disc Dryers Get a Makeover

Wave Discs Revolutionises Traditional Drying Process

21 June 2017

In the search to find a more efficient way of manufacturing industrial disc dryers for the meat-rendering industry, Melbourne-based engineering company Pinches Group has developed a new technology called Wave Disc.

THE CHALLENGE

Traditional rotary discs comprise of a series of stainless steel discs, welded back-to-back and attached to a centre pipe. Together, the pipe and discs make up the shaft, which operates under steam pressure and rotates within a stainless steel shell.

Employed throughout the world in a wide range of industries, disc dryers are commonly used to dry materials such as coal, sand, sludge, paper pulp and animal waste.

There are significant inefficiencies in the manufacturing of disc dryers:

  • Discs are cut from industry standard rectangular plate, with the centres and corners of the donor material often wasted;
  • Flat discs rely on pressure-welded pins for structural support. A typical two-metre diameter disc requires ninety-six support pins pressure welded with full penetration on both sides of the disc. Pressure welds are not only labour intensive, but due to the proximity of discs with the drum, they are difficult to repair once the dryer is in operation.

ASSDA Member Pinches Group began investigating designs that could overcome the need for support pins and reduce raw materials waste. Rather than cutting the discs, Pinches discovered that using specific rectangular sections of material discs could be formed through a series of folds along one edge of the plate. This enable all supplied materials to be used in the formulation of the disc.

BENEFITS

Because folds occur consistently and consecutively around the disc, the folds reinforce the structure of the discs and eliminate the need for added support.

Removing the pins not only improves manufacturing time, it eliminates the chance of weld failure around the support pins, which can cause equipment faults in traditional disc dryers.

Additionally, the natural waves of the discs provide increased agitation to drying material, which can improve evaporation rates.

One design flaw with flat discs is a tendency for product to stick and build up between discs. With Wave Disc, the waves in the disc massage the product and keep it moving within the drum, preventing build up and ensuring that all raw materials are exposed to heat.

Wave Disc also provides greater surface area. Any indirect drying processes (where the heat source doesn't make direct contact with the product) is reliant on the surface area to transfer heat.

With the addition of the folds, Wave Disc provides a surface area at least thirteen per cent larger that conventional discs within the same footprint. This means that existing disc dryers can replace their current shaft with a Wave Disc shaft and increase the capacity of the dryer.

AWARD WINNING DESIGN

In 2012, the Wave Disc concept received top level funding from the Australian Federal Government's Commercialisation Australia program.

In 2014, the first Wave Disc unit was installed at animal by-product processor, Australian Tallow, in Brooklyn, Victoria. Since then, further units have been exported to by-product processors in New Zealand.

As Australia's leading supplier of processing equipment to the animal rendering industry, Pinches Group developed Wave Disc to overcome specific inefficiencies within the meat processing industry.

Now that this innovative new technology has been tested and proven in the rendering industry, Pinches has plans to expand their focus to heating and cooling processing technologies in the food and agricultural sector.

Pinches Group own and operate a testing facility in Melbourne which incorporates an operational Wave Disc pilot unit used by prospective clients and educational institutions for running trials on a range of raw materials.

Among other metrics, the pilot units can provide clients with evaporation rates and in-an-out moisture levels for specific products.

PATENT

The Wave Disc design is protected by Provisional Patent Number 593495.

This article in Australian Stainless Magazine Issue 59 (Winter 2017).

Stainless Steel Transforms Meat Processing Plant

27 October 2016

Over 17 tonnes of stainless steel has been used for the upgrade of a premier meat processing plant to support the growing local and global demands of Australian red meat supply.

The Australian Lamb Company (ALC) currently exports lamb to more than 60 countries worldwide, and recently secured a 10-year contract to process lamb for Coles supermarkets in eastern Australia.

ALC’s multi-million dollar investment to support demand and increase production capacity included the expansion and upgrade of its meat processing operation in Colac, Victoria.

ASSDA Member and Accredited Fabricator Stainless Steel Associated Fabricators (SSAF) Australia was engaged to design, manufacture and install 65 box conveyors spanning 400m, three access walkovers and 30 production tables for the plant’s re-engineered automated boning room.

The conveyor system was designed by SSAF Australia with input from the ALC’s production team to achieve optimum process flow. The main criterion for the mechanical design was excellent product transfer, mechanical reliability and optimal hygiene through easy cleaning of the conveyor’s belt and frame.

The box conveyors are a semi-modular design using the latest SEW-EURODRIVE MOVIGEAR® SERVO motors and gearboxes. Compared with conventional motors and gearboxes, SSAF Australia’s Managing Director Chris Stacey said these systems are significantly more efficient in reducing power usage and allowing a wider speed range without loss in torque.

Grade 304 stainless steel with a 2B finish was specified and used for the upgrade, supplied by ASSDA Sponsors Atlas SteelsMidway Metals and Vulcan Stainless.

Grade 304 stainless steel is a standard requirement in the food industry where acid and salt are not present in the production process. With rigorous standards in food safety and hygiene to adhere to, the boning room must be washed down daily and to this end, the conveyors incorporate CIP (clean in place) systems.

Stacey said that grade 304 2B stainless steel with a PVC protective coating is the material of choice for their food grade equipment. ‘By taking care during manufacture and polishing welds to 320G, 2B is superior to a No 4 or bead blasted finish. The smoother grain structure is much better than No 4 in inhibiting the growth of microorganisms and is easier to clean. Our equipment is regularly swabbed for surface cleanliness and this is critical to our customers’ Quality Assurance (QA) requirements.’

With the full scope of works completed within a 6-month timeframe in early September 2016, the increased capacity of ALC’s Colac operation has delivered significant benefits for the Australian lamb industry and a boost in the Victorian economy.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Images courtesy of SSAF Australia.

Revision of AS 1528: Fluid Transfer in Stainless Steel Tube and Fittings

26 May 2016

Connections are vital

Any visit to a dairy, beverage or food processing plant will drive home the critical importance of the connections between the tanks, mixers, driers, pumps, etc. The image above (courtesy of TFG Group) showing an image of a brewery is a typical example. These tubes and/or pipes carry the process materials, the heating or cooling or wash water, gases, and also dispose of the wastes.

 

Getting the right standard

Except for high pressure or very aggressive environments, most tube is rolled into shape and welded longitudinally. For mechanical or structural service such as columns or handrails, the weld must penetrate and be sound although to perform its mechanical function, it may not need to provide a seal. This is reflected in the basic test requirements of standards such as ASTM A554 ‘Welded Stainless Steel Mechanical Tubing’ and is a reason why it is cheaper and is sometimes used, in error, for fluid transport. Despite these restricted requirements, the external finish is often critical for aesthetic reasons as seen on the handrails in the figure on the right.

Verification of leak tightness is the reason why tubing standards for carriage of fluids, e.g. AS 1528.1 or ASTM A269 or ASTM A270, all include either hydrostatic or 100% eddy current testing. Section 8.4 of the ASSDA Reference Manual summarises the test requirements of the plethora of tubing (and piping) standards commonly used in Australia. However, the food and sanitary industries also require surfaces that are readily cleanable. Hence, in addition to a lack of leaks, there are also requirements on the profile of the weld bead in the tubing, potential crevices in fittings and the surface finish of product contact areas. 

System design and installation

Quite apart from the manufactured components, the system design must include adequate slope for self draining (including across welded joins), simple cleaning procedures, velocities above ~0.5m/sec for low solids streams, at least double that for high solids content and avoidance of design features permitting stagnant zones or dead legs. Excess velocity (at least below about 40m/second) is not a concern for stainless steel, although it may increase noise and pumping costs. These are matters for another place.

Material selection

There are quite complete sets of corrosion resistance data for single corrosives (and some mixtures) at a variety of temperatures and concentrations but they are usually for continuous exposure.  For some acidic, hot and salty fluids or slurries such as sauces, high alloy stainless steels or even nickel-based alloys may be required and such components are rarely “off-the-shelf”. However, for apparently aggressive fluids processed in batches, the intermediate cleaning will arrest the initiation of attack and restore the passive layer so that standard 316(L) material is usually adequate especially with the highly polished finish often used to enable cleanability. One operational issue is that cleaning chemicals can be quite aggressive and the procedures must ensure that residues from cleaning do not remain and are not able to be concentrated and cause corrosion or hygienic issues.

Food tube and fittings – AS 1528

The weld bead is a potential source of crevices and for food tube, its effect must be removed without causing additional surface defects. AS 1528.1 requires the weld bead to smoothly blend without harmful markings. It also sets a nominal surface roughness (0.3 μm Ra) for the rest of the interior by requiring the use of fixed (1.6mm) thickness 2B material. ASTM A270 ‘Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing’ assumes a sophisticated specifier as it lists a mill finish as well as multiple alternative mechanical or other finishing techniques. Acceptance of minor surface imperfections is by agreement. The specifier may require a surface roughness (Ra) limit – which, of course, would override a grit size specification.

The manufacturing tests (eddy current or hydrotesting) ensure that food tube will hold pressure. For the essential quality assurance purposes, AS1528.1 requires line marking of tube. Finally, food grade tube requires a complementary set of fittings that will fit together. The AS 1528 suite achieves this with screwed couplings (Part 2), butt welding fittings (Part 3) and clamp liners with gaskets (Part 4). Aesthetics may be important and is in the hands of the specifier as the exterior of AS1528.1 tube may be as-produced or “buff polished as agreed”, i.e. polished with grit of a specified size.

The AS 1528 suite started life in 1960 as AS N32, was split into four parts in the mid 1970s and completely revised by an ASSDA driven working group to its present form in 2001. It has been widely accepted especially since the 2006 publication by ASSDA of what is now the Food Code of Practice for the fabrication and installation of stainless steel process plant and equipment in the food and beverage industries.  The New Zealand dairy industry has effectively adopted the AS 1528 requirements for dairy tube and fittings. Multiple overseas suppliers provide tube to the AS 1528 specification.

Food and beverage manufacture is obviously worldwide and this has resulted in national, regional and international standards which are different and locally focused. The sizes of the ISO alternatives (ISO 2037, 2851 – 3) are quite different. The European standard (EN 10357- which supersedes BS4825.1 and DIN 11850) covers similar tube but does not cover the range of sizes commonly used in Australia. The British Standard products (BS 4825) are similar in sizes to the AS 1528, but with a restricted range. The American 3A products also cover a restricted range. 

“As a result, ASSDA is spearheading an industry effort to revise the 15-year-old suite of AS 1528 standards”.

What is in need of review?

There are a number of typographical errors and inconsistencies between the parts, there are only some pressure ratings and the listing of fittings requires some revisions. The tolerance on the tube wall thickness has been narrow and one sided since inception and while the standard allows modification by agreement, the current wall thickness requirement will be reviewed.  Other issues for discussion will be the addition of larger sizes and assessment of differences for internal finishes between parts of the suite. And finally, it is intended that AS 1528 will be converted to a joint Australian and New Zealand standard to formalise New Zealand’s use.

If users of the AS1528 suite of standards have any suggestions for changes or improvements to the standards, ASSDA would welcome your emailed comments to This email address is being protected from spambots. You need JavaScript enabled to view it..

Acknowledgements

This article has drawn heavily on documents produced by the ASSDA/NZSSDA working group dealing with the proposed revision of AS 1528 and in particular Peter Moore from Atlas Steels, Kim Burton from Prochem Pipeline Products and Russell Thorburn from Steel and Tube in New Zealand.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Stainless Delivers State-of-the-Art Production Facility

26 May 2016

Stainless steel has helped deliver improved environmental performance and increased efficiency for a major food production company.

In 2014, Australian agribusiness GrainCorp announced a $125 million investment in a consolidation strategy to integrate its GrainCorp Foods’ manufacturing operations, including the relocation of its Brisbane plant to the existing West Footscray facility in Victoria. This move effectively terminates the use of its coal-fired equipment, giving GrainCorp Foods the opportunity to invest in efficient and environmentally sustainable technology and significantly reduce its carbon footprint.

As a result, GrainCorp Foods’ West Footscray operation commenced its expansion and upgrade in 2015 to deliver a state-of-the-art food processing plant.

GrainCorp awarded the design, engineering and installation to SPX Flow Technology Australia, and SPXFlow awarded ASSDA Member and Accredited Fabricator TFG Group the contract to install and fabricate specialised components for the facility’s new margarine production line.

TFG Group’s Foodline Projects division installed and assembled the stainless steel equipment under the direction of SPX Flow Technology Australia, including numerous pumps, valves, heat exchangers, vessels and specialised processing equipment.

The TFG Foodline Projects team also mechanically installed over 12km of stainless steel pipe, AS 1528 304L and 316L tube ranging from 25mm to 100mm in diameter, and over 6000 fittings supplied by ASSDA Sponsor Prochem Pipeline Products.

Hygiene and cleanability of equipment used in food production is paramount, and the correct specification and fabrication quality of stainless steel ensured this criterion was met.

The TFG Foodline Projects team consisted of 35 specialised welders, fitters and installation specialists to ensure the project’s tight lead-time of 24 weeks to completion was met with zero safety incidents. Orbital welding was applied to ensure speed, accuracy and prevention of bacterial contamination in the products.

As part of the factory upgrade, TFG Group’s Austline Fabrications division assisted with the fabrication and installation of the specialised scalloped stainless steel tank access platforms, break tanks, stainless steel chemical bunds and support racks. Jacketed pipework was fabricated to ensure the internal temperature of the process pipework was controlled to prevent the viscous product from solidifying.

These specialised items were all fabricated at TFG Group’s purpose-built factories in both Western Australia and Victoria, and transported to the West Footscray facility for installation by the Foodline Projects division.

GrainCorp’s investment in its West Footscray plant has delivered a fully integrated facility and a more efficient focal point for the sourcing, refining, and distribution of GrainCorp’s locally-produced edible oils and food ingredients.

This article is featured in Australian Stainless Issue 56 (Winter 2016).

Images courtesy of TFG Group.

Cutting a Carbon Footprint

19 November 2012

Coca-Cola Amatil is reducing the carbon footprint of its 600ml PET bottles by 22% with the help of stainless steel.

Innovation in process technology and the successful application of stainless steel has led to efficiency gains and sustainable outcomes for one of the world's most recognised brands in the food and beverage industry.

In 2011, Coca-Cola Amatil (CCA) announced a $450 million investment in PET bottle self-manufacture, or ‘blowfill’ technology at its production facilities across Australia, New Zealand, Indonesia, Papua New Guinea and Fiji.

Blow-fill technology is a manufacturing technique that allows companies to produce their own PET (polyethylene terephthalate) bottles within their own facility. It allows manufacturers to form, fill and seal bottles in one continuous process at the one location without human intervention. Blow-fill has enabled CCA to make its PET bottles using significantly less PET resin, resulting in production of the lightest-weight bottles in the global Coca-Cola system.

Previously, CCA would buy blow-moulded bottles from a third party supplier, transporting them to its own facility to sterilise and fill with product. CCA’s integration of these three steps into one operation has automated its production lines, creating economies of scale and
optimising efficiencies of operation.

CCA’s Kewdale facility in Perth is one packaging line that recently completed its installation of blow-fill equipment, procured from Krones AG, a German-based process manufacturer.

CCA engaged ASSDA member and Accredited Fabricator TFG Pty Ltd for the installation and fabrication of the stainless steel interconnecting pipework for the facility’s new blow-fill equipment.

Sydney-based ME Engineering detailed the scope of works, and coordinated the process engineering and installation of the new equipment.

Over 6km of 304L and 316L AS1528 standard grade stainless steel tube was supplied by ASSDA sponsor Prochem Pipeline Products, ranging in size from 25mm-200mm diameter.

The TFG team purge TIG welded all stainless steel components on site and internally passivated the stainless steel using citric acid.

ME Engineering’s Project Manager Andrew Meagher said grade 316L was specified for CCA’s Kewdale facility because of the high chloride content of the water supply in Perth.

With spring water one of CCA’s main products, sanitation is key to avoiding microbiologically-influenced corrosion.

Tom Moultrie, General Manager of TFG, said that whilst there are other materials that can be specified for equipment using compressed air, stainless steel provides aesthetic appeal, trusted hygiene and longer life span.

The use of stainess steel has been successful in the output of this project, with CCA’s State Projects Engineer Simon Wall stating that ‘as a beverage manufacturer, food safety aspects of our processes and equipment are critical to ensuring the integrity and quality of our products – an area that stainless steel ensures.’

Kewdale’s new blow-fill line commenced operation in June 2012. It features 14 blowing stations, 108 filling nozzles and 18 capping stations, and has the capacity to produce 26,000 bottles per hour.

Mr Wall said the investment in PET bottle self-manufacture will continue to deliver savings in raw materials - bottles are made using less PET resin and less water is used in the bottling process - and meet future consumer growth and demand.

CCA’s ongoing commitment to innovation and sustainability has maximised production capabilities whilst minimising the use of resources.

By the end of 2012, 10 blow-fill lines will have been deployed across CCA’s production facilities in Australia, bringing self-sufficiency to over 70%. Once all 26 production lines are implemented, CCA estimates a saving of 7000 tonnes of PET resin per year, a 15% reduction in bottle weight and 50,000 truck movements eliminated per year. Overall, this is reducing the carbon footprint of every 600ml bottle by an average of 22%.

Images courtesy of TFG Pty Ltd.

This article is featured in Australian Stainless magazine, issue 52.

Stainless Steel and Nickel - 100 Years of Working Together

19 November 2012

This is an abridged version of a story that first appeared under the same title in Stainless Steel Focus No. 07/2012.

The Nickel Institute's director of promotion, Peter Cutler, and consultant Gary Coates, reveal some of the reasons for the continuing popularity of nickel in stainless steels.

Stainless steel is everywhere in our world and contributes to all aspects of our lives. We find stainless steel in our homes, in our buildings and offices, in the vehicles we travel in and in every imaginable industrial sector. Yet the first patents for stainless steel were issued only 100 years ago.

How did this metal become so desirable over the past century that more than 32 million tonnes was produced in 2011? And how does nickel, a vital alloying element in most stainless steel alloys, contribute to the high demand for stainless steel?

THE 'CREATION' OF STAINLESS STEEL
By definition, a ‘stainless’ steel has a minimum level of about 10.5% chromium, so the discovery of chromium in 1799 by Nicolas Louis Vauquelin in France was the first key event in the creation of stainless steel. In 1821 another Frenchman, Pierre Berthier, published research that showed a correlation between increasing chromium content and increasing corrosion resistance, but the high carbon content of his alloys prevented them from showing a true ‘stainless’ behaviour.

Still in France, in 1904 Leon Guillet first published his metallographic work on alloys that today would be classified as ferritic and martensitic stainless steel. In 1906 Guillet published his work on the nickel-containing austenitic stainless steel family, but his studies did not include corrosion resistance. Albert Portevin then continued to build on Guillet’s work.

In 1911, a German scientist named Philip Monnartz reported that as the chromium content neared 12% in a steel with a relatively low carbon content, the alloy exhibited ‘stainless’ properties. Further developments then rapidly occurred in many other countries. In the United States, Elwood Haynes started working with martensitic alloys while Becket and Dantsizen were developing a ferritic stainless steel as lead-in wires for electric light bulbs. In 1912, Great Britain’s Harry Brearley worked on a 13% chromium martensitic alloy, initially for high temperature service in exhaust valves for aeroplane engines.

Meanwhile in Germany, Eduard Maurer and Benno Strauss were testing nickel-containingalloys and, in 1912, two patents were awarded. One of these grades, containing about 20% chromium and 7% nickel, was called V2A, and was found to have exceptional corrosion resistance in nitric acid. That grade had a relatively high carbon content compared to today’s stainless steel, and would be
similar to a Type 302 (EN 1.4317) stainless steel. 100 years later, the most commonly used alloy for nitric acid is 304L (EN 1.4307) with approximately 18.5% chromium and 8.5% nickel, quite similar to the V2A composition other than having a much lower carbon content.

Brearley’s martensitic stainless steel alloy would not rust when wet. He worked with Sheffield cutlery manufacturers to forge it into knife blades and then harden it, replacing the carbon steel blades they were then making. Stainless steel knives rapidly became a common household item. However, for forks and spoons, where high hardness was not so important, the 18-8 (302) composition became the most commonly used alloy.

300 SERIES
We normally think of the austenitic or 300 series family of stainless steels as the ‘nickel stainless steels’, but many other families contain nickel. One of the prime reasons for using nickel in the 300 series alloys is that nickel is an austenite former, but other reasons include:

  • Nickel adds corrosion resistance, especially in certain aqueous environments, and in certain high temperature environments.
  • Nickel can retard the formation of embrittling intermetallic phases at elevated temperatures, a major downfall of the non-austenitic families.
  • The austenitic structure can mean high toughness at cryogenic temperatures.
  • The advantages of the 300 series extend to welding and forming operations.

A fuller discussion of these topics can be found in 'The Nickel Advantage - Nickel in Stainless Steels', available on the Nickel Institute website.

200 SERIES
The 200 series stainless steels are also austenitic in structure. The standardised 200 series grades, which have chromium contents close to the level of a 304L alloy (about 18%), have an intermediate level of nickel. The ‘non-standardised’ 200 series not only have lower contents of nickel, but also lower contents of chromium, with the net effect of significantly reduced corrosion resistance, although still an improvement over the 11-13% chromium ferritic stainless steels.

DUPLEX
The duplex (austenitic-ferritic) family of alloys also need some nickel as well as nitrogen to ensure proper austenite formation. Most ‘matching’ duplex filler metals are actually over-alloyed with nickel to ensure that the welds have the required properties.

PRECIPITATION HARDENABLE
The precipitation hardenable (PH) stainless steel family contain nickel, which increases their corrosion resistance, ductility and weldability compared with hardenable non-nickel-containing stainless steel alloys. One of the other major advantages of the PH grades is that, unlike the martensitic grades, they do not need a quenching operation, which considerably reduces risk of distortion. Some of the martensitic grades also contain a small nickel addition. In the higher chromium types, the nickel is needed for the martensitic transition. In all nickel containing martensitic grades, nickel improves their corrosion resistance, ductility and weldability.

Some of the lower alloyed ferritic grades such as UNS S41003 (EN 1.4001) and S40975 contain a small intentional nickel alloying addition that allows for grain size control, which aids especially in welded constructions. A few of the higher alloyed ferritic grades also have a small nickel addition to increase toughness and ductility, which is beneficial during both hot rolling and in their end use.

Clearly, it is important for each specific application to select the appropriate alloy or alloys to give the desired properties.

GROWTH IN DEMAND FOR STAINLESS STEEL
According to the ISSF, 300 series stainless steel still dominates the worldwide production figures, as shown in Figure 1.

The properties of the various 300 series grades - created by the addition of nickel - are clearly valued by users, both in industry and the general public. Upwards of two thirds of all stainless steel produced in 2011 fell within the 300 series and close to three quarters of all stainless steel produced contains nickel.

The growth of worldwide production of stainless steel over the past 100 years has been steady, if not spectacular. This has meant that the demand for new nickel has steadily increased along with the demand for stainless steel, as shown in Figure 2. Recycled stainless steel is also a very important component in the alloy supply chain.

EFFICIENCY AND 'GREEN' CREDENTIALS
Resource efficiency is a recurring theme as the global economy faces economic challenges. Stainless steel not only contributes towards efficiency in many applications, it also shows continuous improvement in the resource efficiency related to stainless steel itself.

There are three important factors:

  1. Stainless steel’s long service life, which might average 15 to 20 years, although much longer in prestigious buildings.
  2. The extent of recycling: The percentage recovered and recycled at end-of-life - around 90% - is amongst the highest of all materials. Moreover, this recycling can be repeated many times without loss of quality. While the recycled content may appear to be relatively low, this is simply a result of stainless steel’s long service life (15 to 20 years) coupled with much lower global production 15 to 20 years ago.
  3. Continual production improvements for stainless steel and its raw materials. For example, whilst the ores being processed today are of lower grade than before, the extraction and recovery processes are more efficient.

THE FUTURE
The history of stainless steel would be incomplete without celebrating the extent to which it has enabled innovation not just in the area of improved performance, but also in the more intangible, aesthetic aspects. From chemical plants to medical equipment to iconic stainless steel-clad buildings, stainless steel has made - and will continue to make - a major contribution to almost every aspect of our lives.

With durability, recyclability, versatility and aesthetic appeal at the core of its appeal, stainless steel - with nickel as one of its trusted alloys - is well placed to continue to innovate and expand its applications.

STAINLESS STEEL IN USE

FOOD AND BEVERAGE INDUSTRY
The popularity of stainless steels in kitchens did not go unnoticed in the food and beverage industry.

If we take milk, we know of an early stainless steel bulk milk tank truck from 1927 in the USA. A paper entitled ‘The Corrosion of Metals by Milk’ from the January 1932 Journal of Dairy Science by Fink and Rohrman states: ‘It has long been known that milk in contact with iron and copper will not only acquire a metallic taste, but corrode these metals readily’. At that time, tin-coated metals were commonly used. It went on to say that ‘High chromium nickel (18-8) iron alloys … are very resistant to corrosion by milk and are satisfactory for dairy equipment …’. The modern milk processing industry is filled with stainless steel equipment, mostly of Type 304 (EN 1.4301) or 304L.

The report also went on to state that some materials that are otherwise suitable for processing of milk ‘…do not stand up well to the action of cleaning compounds that are commonly used in dairies’, but that the 18-8 alloy was suitable for those cleaning compounds. Today, the typical cleaning acids and hypochlorite sanitising compounds that are used not only in the dairy industry but also in most food and beverage plants worldwide, require that same 18-8 alloy as a minimum. A correctly chosen stainless steel alloy will not change the taste or appearance
of the food product. However, it is the ability to withstand repeated use of the sanitising chemicals over the lifetime of the equipment that has led to the widespread use of stainless steel in all sectors of the food and beverage industry. Producers are then able to guarantee the
safety of their food products.

ARCHITECTURE
Another area of quick acceptance was in architecture. The first recorded use for that purpose was in 1929 in London at the Savoy Hotel where a sidewalk canopy and a sign were erected with the 18-8 alloy. These were soon followed by two iconic skyscrapers in New York that used stainless steel as a dominant element on their exteriors: the Chrysler Building in 1930 and the Empire State Building in 1931.

Since then, many prestigious buildings around the world have used stainless steel, including the Petronas Tower in Kuala Lumpur, the Trump Tower in Chicago, and the Jin Mao Tower in Shanghai. Related to architecture is sculpture, and Isamu Noguchi convinced the Associated Press in 1940 to approve stainless steel instead of bronze for his sculpture above the entrance to its building in New York. Since then, artists around the world have been using stainless steel, mostly either 304L or 316L (EN 1.4404), in their works. The St Louis Arch in the USA, Frank Gehry’s Peis (Fish) in Barcelona, Spain, and more recently Genghis Khan in Mongolia are examples of what can be done with stainless steel.

TRANSPORTATION
During the Great Depression in the USA, Edward Budd realised the untapped potential for stainless steels. Although their use in aeroplanes was his first application, his legacy remains the building of more than 10,000 passenger railcars, some of them still in use today.

Around the world, stainless steel is used extensively for passenger rail cars for subways, commuter trains and long distance trains, ensuring safety plus long life and low maintenance costs. In addition, stainless steels are used to transport cargoes such as food products, petroleum products and corrosive chemicals by rail, road, water and even air, both domestically and internationally.

ENERGY
In the broad field of energy, stainless steels have been used to extract oil and gas containing hazardous substances as well as for use in the refining stages. For power plants, stainless steel is used extensively at both low and high temperatures, whether the fuel is coal, oil, gas, uranium or waste products. Hydroelectric stations use stainless steel for dam gates as well as turbines. Many of the established sustainable
energy technologies such as solar and geothermal are using stainless steel, as well as the present biofuels industry with corn or sugar cane as feed stock.

WATER
Fresh water is an essential commodity for mankind, and stainless steel is used extensively in treatment plants for potable water as well as for wastewater. Cost effectively producing fresh water from seawater or brackish water by desalination also requires the use of stainless steel. In some countries, underground stainless steel pipe is used to deliver potable water to homes to prevent leakage, or in other special cases to protect either the environment outside the pipe or the water inside the pipe. Stainless steel plumbing is also common in certain countries and offers a long lasting, low maintenance option.

SURGERY
The first recorded example of an austenitic stainless steel surgical implant is from 1926. Medical instruments are also known from that time period. The ability to easily and repeatedly sterilise components that come in contact with the human body or are used in hospitals and clinics contributed to the early acceptance of stainless steel. Today, there are well-established international specifications for materials used in this industry. For example, stainless steel alloys for implants must meet stringent metallurgical cleanliness requirements and be completely non-magnetic so that the patient can safely undergo diagnosis by Magnetic Resonance Imaging.

FUTURE USES OF STAINLESS STEEL
Strong growth in the use of stainless steel has continued in the past decades despite the rapid and diverse developments in other materials and the more recent economic turmoil. The nickel-containing alloys in the 300 series still account for nearly two thirds of current stainless steel production worldwide, and there is nickel in the 200 series, duplex and precipitation hardening families, as well as in some of the martensitic and ferritic alloys. The reason for this is the great value that is placed on the properties which nickel provides.

Society is rapidly evolving and facing challenges on a global scale. Population is increasing, expectations are growing and resources are limited. Therefore we must use those resources more efficiently. This is particularly apparent for energy where stainless steel, and especially the nickel-containing alloys, already plays a major role in the more difficult to extract fossil fuels. Stainless steel’s corrosion and heat resisting properties are key to more cost-efficient operations. This also applies to the renewable sources that are now being developed, such as wave power and biofuels from new organic sources.

The worldwide need for higher quality, safe food and beverages and water will only increase, especially as food products can come from anywhere in the world. Stainless steel has evolved as the material of choice in this industry, both industrially and domestically, and it is likely to continue to meet the demands of a global population that is predicted to increase to nine billion by 2050.

This growing population, combined with a rapid movement to urbanisation, requires an expanded and more efficient transport infrastructure. The characteristics of stainless steel enable it to deliver lightweight and durable designs, leading to more efficient performance, safety, lower energy requirements and reduced emissions while giving lower life-cycle costs.

Image of Trump Tower (Chicago, USA) pictured above courtesy of C.Houska.

This article is featured in Australian Stainless magazine, issue 52.


Posted 3 May 2012

As bottled water continues to gain popularity in Australia, maintaining the quality and purity of the water extracted from natural springs is paramount.

This is just one example within the food and beverage sector where hygiene is vitally important and, therefore, stainless steel continues to be the material of choice for processing and storage facilities.

In 2011, Coca-Cola Amatil (CCA) commissioned ‘Project Flint’ to upgrade three spring water storage tanks for their Moorabbin plant in Victoria plus an additional two tanks for their Thebarton plant in South Australia.

GEA Process Engineering Australia engaged Byford Equipment on behalf of CCA to fabricate and install the five storage tanks.

GEA Engineering’s General Manager Operations, Andrew Fillery, said stainless steel was an important specification as the tanks had to cope with the chemical and thermal rigours of cleaning processes.

“Stainless steel was chosen for process and hygienic reasons, and the vessels needed to withstand the process and cleaning conditions where mild caustic and acid CIP solutions were used,” said Fillery.

Strength and durability was key for the 200,000L capacity silos, which measured 4.7m in diameter by 14.5m high for the Moorabbin site and 5.5m in diameter by 10m high for the Thebarton plant.

ASSDA Sponsor Midway Metals supplied 27 tonnes of grade 304 stainless steel coil with a 2B finish in 2mm, 2.5mm, 3mm and 4mm thicknesses. The coil widths were 1219mm and 1500mm.

With a team of five fabricators on the project, the tanks were welded together using a semi-automatic MIG welding process. The welds were then pickled to restore the chromium oxide layer and abstain from rusting.

Byford Equipment’s Project Manager Geoff Smallwood said coordinating the delivery of the tanks was a challenge, given the logistics of travelling through three states by road.

The delivery of the vessels was critical added Fillery, as there were specific installation windows to work within.

The storage tanks were delivered from Byford’s workshop in New South Wales to Moorabbin in March 2011. The two remaining tanks were delivered to Thebarton a month later for installation. It took one day and one crane to install each tank on site.

The connecting pipework was positioned on site, which was grade 304 polished tube in diameters ranging from 38mm to 150mm and purge welded prior to installation.

Images courtesy of Byford Equipment.

This article is featured in Australian Stainless magazine, issue 51.


Posted 9 December 2011

A worrying trend among Australia's major resource companies is the increasing amount of engineering, detailing and fabrication work being sent offshore - a move that has had significant impact on local fabrication. But there are some positive signs in the food and beverage sector that local fabricators are more than capable of meeting design and fabrication expectations.

When ASSDA member and Accredited Fabricator, A&G Engineering, put in a bid to build 10 x 100 hectolitre beer fermenters for Casella Estate - a company best known for their Yellowtail wine label - they had to compete against companies as far away as Europe for the coveted project.

But A&G had a few advantages over the offshore companies: they had worked with Casella before, fabricating 88 x 1.1 million litre wine tanks for the company’s tank farm in Yenda, NSW; they have supplied stainless steel tanks to Australia’s leading breweries, wineries and beverage companies; and they are one of the largest users of stainless steel in Australia.

A&G’s win is an important victory for the Australian industry as a whole and another milestone for A&G Engineering, which was founded in 1963.

The five-month Casella Brewery project, completed in August 2011, saw 25 of A&G’s 200 staff use 65 tonnes of 304 grade stainless steel (including 2-4mm coil and 8mm plate) to build the 10 vessels.

A&G’s Design Manager Heath Woodland said the tanks were designed to AS1210-2010 pressure vessel standards, in order to withstand a pressure rating of 115kPa.

The stainless was welded with A&G’s semi-automated welding process and the internal welds were polished to achieve a 0.6Ra surface finish, to meet beverage industry standards of a food grade finish.

A&G built the vessels at their Griffith and Irymple plants, before transporting them to Yenda. With the beer fermenters now in place, it is hoped the Casella Brewery will be operational by the end of 2011.

Images courtesy of A&G Engineering.

This article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.


Posted 1 March 1998

Stainless steel forms a significant part of a beef abattoir, including the conveyors, fixed and elevated platforms, sterilisers, chutes, hand wash basins and, of late, water supply and wastewater piping. The stainless component may now expand even further in new abattoirs with the recent development of cast stainless steel skids and forged hooks for use on dressing conveyors.

AbattoirDressing conveyors in beef abattoirs traditionally use rollers rather than a skid system or, in some cases, extruded aluminium skids and hooks are used. Both of these systems have limited service lives due to the weight of the beasts. They also result in downtime when cleaning and, in the case of rollers, lubrication is required. Hygiene is critical throughout the trimming process, as the carcass' meat is exposed to the environment.

G & B Stainless (Crestmead, Old) and Meateng (Melbourne, Vic) recognised the need to develop a dressing conveyor system which would allow a rapid turnaround of hooks while assuring a high level of hygiene.

Using stainless steel would provide sufficient strength to hold heavy carcasses (weighing up to 1,000kg), while allowing the skids and hooks to simply pass through a washbox for sterilisation on their return to the starting point of the conveyor.

The project has evolved over six months from a prototype fabricated skid, which did not provide enough strength, to the existing cast skid and forged hook. The cast skid also incorporates a high density polyethylene insert, which is the only component to experience wear during service. This insert can be replaced at low cost when required.

The skids are cast by Austcast Stainless (Northgate, Old) using a vertical joint automoulding sand casting system. Grade AS2074 H5A (equivalent to AISI 304) stainless is used and full traceability exists for the castings, The stainless hooks are forged by John Ure (Wacol, Qld). Production costs are comparable with extruded aluminium skids, but the low rate of replacement makes the lifecycle costs very attractive.

Over 1,000 stainless steel skids and hooks have been in service at Stockyard (Grantham, Qld) for six months and, according to site engineer, Roger Tocknell, they have been performing excellently.

The new skids are not interchangeable with existing mild steel rollers, but G & B Stainless' Director, John Van Koeverden, said the company's next goal is to develop stainless rollers which can be used on existing conveyors.

This article featured in Australian Stainless Issue 11 - March 1998.


Posted 28 February 2000

15 million dollars worth of stainless steel has been used to construct the largest rotary fermentation area in Australia.

The facility at Southcorp's Karadoc Winery in Victoria comprises 88 stainless steel red grade processing tanks, pipes and tubes, brine jackets and rotary fermenters.

Southcorp Wines Engineering Manager (Eastern Region) Geoff Leighton said stainless steel was preferred by the wine industry because it is "corrosion resistant, provides a stable environment for the wine, is easy to clean and maintain and has a long service life."

Grade 304 stainless steel was used for the tanks, with a thickness range of 2mm - 6mm, with the highest tank 1 5 metres tall. An extensive amount of 304 and 316 tube was also used.

ASSDA members Atlas Steel (SA), Alfa Laval, APV Valves and James Contract Supplies were all involved in the project.

The expansion brings the Karadoc site's total storage capacity to approximately 93 million litres.

The winery, which produces known brands Lindemans, Queen Adelaide, Kaiser Stuhl and Matthew Lang exports approximately 60% of its bottled wine production.

"The project has provided infrastructure to the district and significant employment opportunities in the areas of viticulture, transport and production facilities," Mr Leighton said.

Mr Leighton said while stainless steel met the needs of the wine industry, there was room for improvement.

"Stainless steel demand exceeds supply on occasions," he said. "It is not totally corrosion resistant and requires diligence in the specification and fabrication process."

The Karadoc project is one example of current growth in the Australian wine industry, which has brought with it exciting opportunities for the stainless steel industry.

Domestic wine production has increased five fold since 1966, from 156 million litres to over 800 million litres.

Vision 2025, a strategic plan by the Australian wine industry, aims to make the industry a global force by achieving $4.5 billion in annual sales of wine and 6.5% of the value of world production by 2025.

Results to date have been positive, with 1999 total sales estimated to be approximately $2.4 billion and 3.5% of the world export volume.

The number and size of fabrication firms in wine growing regions is expanding and as such, real opportunities to explore new applications and methods of design, fabrication and maintenance exist.

To assist the wine and stainless industries meet their objectives, ASSDA is conducting "Using Stainless Steels in the Food Industry" seminar in May and June which will cover fabrication, corrosion, welding, cleaning and sanitation issues for stainless steel use in the food industries as well as issues specific to the wine industry.

For more information on ASSDA's "Using Stainless Steels in the Food Industry" Seminars, please contact ASSDA on (07) 3220 0722.

REFERENCES
1. Australian Wine Foundation (1996) Strategy 2025 - The Australian Wine Industry.

This article featured in Australian Stainless magazine - Issue 15, February 2000.


Posted 17 May 2001

Stainless steels are widely used in the food industries, including wine production, because of their corrosion resistance and ease of cleaning which result in negligible product contamination.

Long life can be expected from stainless steel equipment provided care is taken with:

> Vessel design
> Grade selection
> Fabrication procedures
> Maintenance practices.

The precautions to be taken are not complicated but are most important - neglecting to follow them can lead to rapid failure.

VESSEL DESIGN
Much can be done in the detailed design to improve corrosion resistance. The two cardinal rules are:

1. Design for complete and free drainage
2. Eliminate or seal weld crevices.

A series of drawings, with accompanying narrative, comparing good and bad design practices, are set out in Part Ill of Nickel Development Institute publication #11 007: Guidelines for the welded fabrication of nickel-containing stainless steels for corrosion resistant services.

GRADE SELECTION
Two stainless steel grades are particularly used in the wine industry, grades 304 and 316, and both 'standard' and 'low carbon (L)' versions are available. Their compositions are shown in Table One below.

Table One: Stainless Steel Grade Selection
GRADE CHROMIUM NICKEL MOLYBDENUM CARBON
304 18.0 - 20.0 8.0 - 10.5 - 0.08 max
304L 18.0 - 20.0 8.0 - 10.5 - 0.03 max
316 16.0 - 18.0 10.0 - 14.0 2.0 - 3.0 0.08 max
316L 16.0 - 18.0 10.0 - 14.0 2.0 - 3.0 0.03 max

The 'L grades are specified w here welding is to be carried out and there is concern that time-at-temperature may be sufficient to precipitate chromium carbides and hence cause sensitisation of the metal, resulting in susceptibility to intergranular corrosion.

The molybdenum content of grade 316 significantly improves its resistance to p1tting and crevice corrosion, particularly in the presence of chlorides. It also increases the material cost by about 20 to 25 percent.

For handling waters, grade 304 is satisfactory up to about 200 parts per million (ppm) chlorides, while grade 316 can be used up to 1 000 ppm chlorides.

Tartaric, acetic, tannic, malic and citric acids are not corrosive to stainless steel at the concentrations found in juices or wines. However, the level of su lphur dioxide is an issue. Grade 304 is generally regarded as resistant to corrosion when immersed in juice or wine at free SO2 levels up to 700 ppm. Above this, grade 316 is recommended. The problem is greater in the vapour space where sulphurcontaining acids can form. Grade 304 is not recommended for use in areas where there is more than 75 ppm SO2 in the liquid. This can lead to composite tanks using grade 316 in the ullage zone and grade 304 in the submerged zone.

FABRICATION PROCEDURES
Cracks and crevices in stainless steel welds can act as initiation points for pitting and crevice corrosion. They can also result in product contamination . The aim should be for smooth weld beads without porosity, slag inclusions or undercut.

During the welding of stainless steels, 'heat tint' is formed. This is a high temperature oxide, rich in chromium which has been drawn from the stainless steel. The result is a very thin low-chromium layer on the underlying stainless steel surtace. For best corrosion resistance, both the oxide film and underlying chromiumdeficient layer must be removed. This can be done by pickling using a nitric/hydrofluoric acid mix, either in a bath or as paste, or by mechanical removal.

Since stainless steel depends for its corrosion resistance on the presence of an extremely thin, continuous chromium oxide film, any contaminants which disrupt this film will reduce its corrosion performance and can initiate pitting. A common contaminant is embedded iron particles from nearby grinding of carbon steel fabrications or the use of iron-contaminated tools. Such contamination can be removed by passivating the stainless steel with nitric acid, followed by a thorough water rinse.

After hydrotesting and before being put into service, tanks should be drained and thoroughly dried. There are too many instances of new stainless steel systems failing due to pitting or crevice corrosion because either:

> Contaminated test water has been left stagnant in the system, or
> The system has been drained but not dried, leaving pools of water to evaporate, concentrating dissolved salts and resulting in corrosive attack.

MAINTENANCE
Stainless steel is inherently a low maintenance material - but it is not zero maintenance. The main requirements are:

> Deposits which build up on stainless steel surfaces should be regularly removed. This is because crevices exist under deposits and crevice corrosion can be initiated in such areas.
> Following cleaning, regular inspection is necessary to establish the condition of the equipment. This will ensure early detection of any developing problems so that steps can be taken to prevent further deterioration.

If guidelines such as these are followed, long and trouble free service can be expected from stainless steel equipment.

Words by David Jenkinson from the Nickel Development Institute.

This article featured in Australian Stainless magazine - Issue 18, May 2001.


Posted 17 May 2001

A stainless steel stackable wine storage and fermentation system has been adapted to carry water for use in hospitals.

STAKVATs feature internal temperature control tubes and a sloped design for complete drainage and radius corners for protection against crevice corrosion and bacteria collection.

Each vat has a storage capacity of 900 litres, can be stacked five high and easily transported on a tray truck. They are also fork-liftable four ways.

The vats are made from grade 316 stainless steel sheet and grade 304 tube. Standard BSM grade 316 fittings are used for the outlets, with door handles and locking pins made from grade 304.

The original STAKVAT design featured replaceable French and American Oak sides used for wine enhancement. The modified STAKVAT has a stainless steel side instead of oak, but maintains the cooling/heating tube system and sloped design.

Oxygenated water is created in the STAKVAT via the airspace in the top of the vat. The water will be circulated through a system of STAKVATs at approximately 30 litres per minute.

Managing Director of Ausvat, Peter Warren said the STAKVAT helped meet an industry need for efficiency in storage space.

"Stainless steel internal cooling systems and the space saved by using STAKVATS produces many cost-effective advantages," Mr Warren said.

Stainless steel for the STAKVATS were supplied by ASSDA member Stirling Stainless Steel, with fabrication by ASSDA members Simcraft Products and Unique Metal Works Pty Ltd.

This article featured in Australian Stainless magazine - Issue 18, May 2001.


Posted 17 May 2001

Nearly four tonnes of stainless steel has been used to extend and upgrade facilities at Cape Clairault Winery in Western Australia's Margaret River region.

The project involved the installation of four 5 000 litre red wine hopper fermenters, four 12 000 litre and one 4 500 litre white wine storage tanks and the upgrade of 15 existing tanks of 1 000 -12 000 litre capacities.

Each hopper has a 20 degree sloping bottom to allow complete drainage after service. The design reduces the need for manual cleaning, a potentially dangerous practice due to the build-up of carbon dioxide in the enclosed tank space.

The white wine storage tanks have a conical bottom, also for drainage, and a two piece controllable heating/cooling system constructed from grade 316 stainless steel high pressure cavity plate. If the tank is only half full, refrigeration can be pumped through just the bottom cavity plate.

The cavity plate, constructed by ASSDA member Simcraft Products also features off-centre dimples for greater distribution of the cooling brine.

To convert the winery's existing tanks from storage to fermentation, high pressure cavity plate and temperature probes were added for cold stabilisation, while one of the 5 000 litre tanks was converted to a fermentation hopper.

The tanks were fabricated or upgraded with grade 316 stainless steel in coil, with all welds acid cleaned with post-fabrication polishing to ensure greater corrosion resistance.

The tanks were fabricated in sections then joined together, stacked one on top of the other. Plug welds were used to reduce the risk of cracking at contact points and for improved corrosion resistance.

Simcraft Products undertook all fabrication for the project. Stainless steel and stainless steel components for the tanks were supplied by ASSDA member Austral Wright Metals.

This article featured in Australian Stainless magazine - Issue 18, May 2001.


Posted 28 February 2002

A combination of grades 304 and 316L stainless steel has been utilised for all contact surfaces in Murray Goulburn's milk processing plant in Rochester, Victoria, which was upgraded in 2000.

The plant comprises an evaporator to concentrate cow's milk and spray dryer to produce various milk powders. Approximately 100 000 litres of milk is processed per hour, with the majority of product for export to over 100 countries. The evaporator and dryer represent more than half of the total project, a capital investment of around A$50 million.

The stainless surfaces and components carry milk feed, evaporated vapour, milk concentrate, milk powder, hot drying gas and cleaning chemicals of alkali and acid.

Ardmona tomato processing plant constructed entirely in stainless steel using grade 304.All product contact surfaces are of austenitic stainless steel grade AISI 304, with the 12m long evaporator tubes being produced from strip then rolled with the seam welded and bead rolled; the tubes have a 2B internal finish.

Principal contractor Niro Australia received instructions to proceed in July 1999 and conducted the first powder trials 14 months later, with commercial production starting November 2000.

To carry out the project, Niro involved Victorian fabricators Stainless Technology and PLC Engineering, though some fabrication was also conducted in New Zealand.

ASSDA member Alfa Laval supplied food grade stainless steel pumps, process valves, tank equipment, fittings and tubing worth over $2.5 million. The total supply was in excess of 40 tonnes and included 40km of tubing in sizes 1" to 6".

Grade 316L stainless steel was used for wetted parts (parts in contact with process fluids) and 304 for non-wetted areas. Products were generally supplied with a no.4 external surface finish; AS 1528 was used as the guideline for component standards.

Many of the process pumps and valves were chosen for their product handling characteristics. Specialist mixproof valves, which allow two different products to travel through the same valve without fear of intermixing, and high efficiency pumps were selected. Spillage-free mixproof valves were specified to prevent accidental discharge onto process floors and ensure a clean process environment, and rotary lobe pumps were selected for their gentle handling of cream products.

Pre-fabrication of many of the valve and pipework assemblies was carried out off-site in controlled environments. Due to the critical nature of the process applications, importance was placed on welding techniques and subsequent cleaning of welds. Valve manifolds were pre-fabricated and transported to site on completion, minimising the number of critical welds performed on site.

TOMATO PROCESSING
Fifty thousand tonnes of tomatoes have passed through Ardmona's processing plant in Mooroopna, Victoria, since it began operation a year ago.

The $15 million plant, which produces whole peeled and crushed tomatoes, was constructed entirely in stainless steel using grade 304 for the structural components and 316 tube and fittings for the wetted parts. Stainless steel was specified for its corrosion resistance and low maintenance, and to meet the health and safety requirements of a food processing plant.

Designed with a life expectancy of 30 years, the plant is capable of processing 40 tonnes of tomatoes per hour.

Ardmona's Engineering and Production Department, in conjunction with Italian firm Sasib Foods, were responsible for the design, engineering and construction aspects of the nine-month installation.

This article featured in Australian Stainless magazine - Issue 20, February 2002.


Posted 1 September 2002

A contaminant-free surface is a critical requirement of the food processing sector and electropolishing is a highly effective way to achieve the level of surface smoothness required for keeping stainless steel components scrupulously clean.

Pillsbury Australia in Melbourne's outer east is one of a growing number of food processors who have opted for electropolishing for hygienic and durable stainless steel components. Pillsbury produces the fresh pasta brand Latina Fresh. The range consists of filled pasta types like ravioli and tortellini for which the fillings are cooked during manufacture, but the consumer completes the cooking process at home. For some years now, Pillsbury has specified an electropolished finish for all its stainless steel food preparation equipment and related components such as trolleys, cooling racks and other fittings. These are manufactured by GP's Fabrications and electropolished by ASSDA member MME Surface Finishing.

As well as promoting hygiene, electropolishing enhances stainless steel's corrosion resistance. Many fittings in Pillsbury's plant have been in constant operation for eight to ten years and show no sign of surface deterioration despite exposure to steam-laden, high temperature atmospheres.

Electropolishing works by selectively removing surface metal thereby smoothing and levelling the stainless steel. This is done by immersing the component in a chemical bath to which lowvoltage electric current is added. Stock removal is controlled to a high degree of accuracy by adjusting the time, temperature and current density.

The resulting finish is free of surface flaws and impurities, giving no opportunities for deposits to lodge and contaminate the food product. A further benefit is that it makes the components easier to keep clean, allowing for longer periods of processing activity.

This article featured in Australian Stainless magazine - Issue 22, September 2002.


Posted 1 September 2002

A new technique for manufacturing high pressure cavity plate for heat exchange applications developed by the Australian stainless steel industry increases the options available to the food processing and manufacturing sectors.

'Laser welded cavity plate' has been developed by ASSDA member J Furphy & Sons, a Shepparton fabricator of stainless steel tanks and processing equipment, as an alternative to resistance or plug welded dimple plate used for the heating or cooling jackets on stainless steel tanks, vessels and silos.

A wide range of industries stands to benefit from the new cavity plate, from dairy, brewing, food, wine, pulp and paper, chemical, pharmaceutical, refrigeration to textiles and manufacturing.

It is designed to be used in jacketed tanks, pressure vessels, shells and heads, troughing, chutes and hoppers, immersion plates, bank assemblies, baffles, ice-making plates, water chillers and food cookers.

The method of manufacture allows design flexibility enabling it to be tailored to specific performance requirements. It can be designed to suit both the flow characteristics of the refrigerant or heating medium and the required performance objective for the equipment by programming the cavity pattern and dimensions into a CNC controlled laser welding system.

The process involves laser welding two sheets of stainless steel in their flat form and inflating to form the cavity through which the cooling or heating medium is transferred.

The laser welds are exceptionally strong and have been burst tested in excess of 13 000 kPa, with most common demand being for operating pressures between 300 and 3 000kPa.

The product is available single embossed for uses where a flat inner wall is required or double embossed for immersion where both sides of the plate are utilised to heat or chill.

It is in use in chocolate crucibles in the confectionery industry as well as in Peerless Holdings’ edible oils processing tanks. Orbis Engineering has used the cavity plate in a cooling tunnel conveyor bed and Barry Brown & Sons has utlised it in on-farm milk silos. It has also been used in various major winery projects, including Peace Wines and Jindalee Estate, for fermentation and storage vessels.

Another ASSDA member, A&G Engineering of Griffith, has specialised in cavity plate for use as a cooling plate in wine vessels for a number of
years. This product also incorporates technology unique to Australia.

This article featured in Australian Stainless magazine - Issue 22, September 2002.


Posted 1 June 2002

The Australian construction and food processing sectors can specify stainless steel tube in large sizes with confidence in its quality and timely delivery, now that local production has commenced at a Victorian plant.

Manufacturing by an Australian firm will also make it easier for specificiers to communicate their special requirements.

Stainless Tube Mills' special purpose factory in Melbourne’s outer east is producing longitudinally welded tube in diameters up to 300mm and wall thicknesses up to 8mm – the largest seamwelded stainless steel tube available in Australia. Tube in this size range has always been imported.

The recently commissioned draw mill, designed in house by ASSDA member STM in conjunction with CSIRO, joins twelve other mills on site which produce welded tube up to 101.6mm outside diameter.

While a conventional mill uses a drive mechanism to feed the strip through the mill and produce welded tube, in the draw mill strip (1) is drawn through the mill with the forming rolls idling (2 & 3). This has the effect of producing a tube with minimal roll forming marks, as well as precise tolerances. The internal weld bead (4) is rolled to merge with the parent metal producing a smooth bore. Externally, the polished finish renders the seam all but invisible.

The smooth interior finish means tube produced on the draw mill is ideal for transfer of processing fluids, particularly food products, where the clean internal bore is mandatory.

Large diameter tube is also finding application architecturally for balustrades, barriers and structural column formers. As formers they make an attractive alternative to brick or concrete,
delivering a superlative appearance and impressive structural strength, which can be further bolstered by filling with concrete. STM used 300mm columns in T304 alloy to dramatically enhance its own office façade (left).

The draw mill has only been in operation commercially for a short time, however STM reports there has already been considerable demand. The firm's future plans include production of heavy walled large diameter sectional tubes for architectural applications.

This article featured in Australian Stainless Issue 21 - June 2002.


Posted 1 June 2002

A major new development project at the Jindalee Winery at Moorabool near Geelong utilises over 100 tonnes of grade 304 2B finish stainless steel. Shepparton’s J Furphy & Sons fabricated 95 wine storage and fermentation tanks, ranging in size from 75,000 to 1,200 litres.

The new tanks provide almost three million litres of temperature-controlled storage capacity for grapes processed from the adjoining vineyard and a much larger vineyard which Jindalee’s owners, Vince and David Littore, operate in the Murray Darling region near Mildura.

Three years ago the Littore Brothers acquired the former Idyll Vineyard and winery at Geelong which they are now using as the production centre for their wines produced under the Jindalee and Fettlers Rest labels for both local and export markets.

In addition to the tankage, most of which features the new Furphy Laser Welded Dimple Plate design which provides the cooling jackets to the tanks for circulation of refrigerants, Furphy’s have also completed more than 350 lineal metres of galvanised walkway and tank access systems.

Jindalee’s winemaker Scott Ireland describes the project as a state of the art winery facility designed to produce wines which will appeal to the most discerning palates as well as capitalising on and growing the export market success already achieved under the Jindalee label.

A $1 million bottling hall and packaging facility will be added providing a fully integrated facility.

This article featured in Australian Stainless Issue 21 - June 2002.


Posted 1 July 2003

John Hodgkinson is mad about hams! The managing director of ASSDA member Smo-King Ovens really loves his products and is passionate about helping butchers generate more business through their use.

You may not have noticed these stainless steel ovens that are an important element of nearly every quality butcher shop in Australia. Just as you can tell a good patisserie by their éclairs, you can tell a good butcher by their smoked hams!

Of 304 stainless steel construction, Smo-King ovens are used extensively for smoking and cooking hams, bacon, roast meats, poultry, fish and a wide range of smallgoods. Cakes and pastries can also be made in one oven which can operate at temperatures high enough to allow baking.

“The 304 stainless steel ensures that the ovens are corrosion and stain resistant”, says Hodgkinson. “It also means they are very durable, easy to clean and many health and food safety authorities insist that stainless steel is used in all food processing applications if the equipment comes into contact with the food as it does in a smoke oven – plus it fulfills our requirement for high quality while still providing acceptable cost.

“I’ve been longing to make my own smoked products”, says Wally Dafter. Dafter’s Quality Meats is located in Charmhaven on the NSW Central Coast. “We have one Smo-King oven which operates at least four days a week and currently we produce 10 different types of smoked goods”, he says.

“We reckon our smoked foods are really good”, enthuses Dafter who is planning to enter them in the 2004 Royal Easter Show.

John Hodgkinson believes Smo-King ovens are about 70%-80% of the price of European ovens with similar features. “These ovens definitely allow our customers to add value to their products and their business”, says Hodgkinson.

This article featured in Australian Stainless magazine - Issue 25, July 2003.


Posted 1 July 2003

Consumers expect processed foods to be tasty and nutritious, affordable and safe. To meet these expectations, food contact equipment has to be hygienic and productive.

A manufacturer’s wish list for its food processing components might read like this:

>    durable, with easy release and easy-to-clean surface
>    inert, non-toxic and non-contaminating
>    corrosion-resistant and non-degrading
>    suited to continuous, in-line sanitation and cleaning
>    impervious and non-absorbent to food products, odours, stains and colourings
>    economical, reliable and safe over its entire working life
>    temperature versatile and highly conductive, eg from cooking to cryogenic temperatures
>    smooth, seamless, one-piece construction
>    removable and replaceable
>    repairable/maintainable by existing technologies.

At first sight this seems too much to ask of any single product, but stainless steel conveyor belts fit the bill.

Unique Belting for the Food Industry
Continuous carbon steel belts were introduced into US and European bakeries in the 1920s and are today used primarily for processing baked goods. ASSDA member Sandvik launched a stainless steel belt in 1931 to withstand wet or corrosive conditions in the food and chemical industries.

The product found a foothold in the market and increasingly since the 1960s, the stainless steel belt has moved from being a simple food conveying medium to a processing platform. Now ranging in width from 200mm up to several metres and in solid or perforated forms, stainless belts are used in cooling (chilling, freezing, pastillating, freeze drying), heating (drying, roasting, blanching, steaming) and mass transfer (dehydrating, aeration, dewatering) for value added processing of foods. Stainless provides superb temperature versatility, from -200ºC (in cryo-freezing belt tunnels) up to +300ºC (high-temperature cooking tunnels). It can be continuously sanitised during operation using zoned washing boxes fitted to the lower strand of the belt.

The smooth, continuous stainless belt is also versatile in the types of food product it can convey and process – powdery, granular, fragile, bacterially-sensitive, sticky, viscous, sharp, pasty, slurry, runny, chunky, awkward, hot, oily … you name it, chances are it can be handled by the stainless belt. Accordingly, the stainless belt has found application over wide areas of wet food processing – for dairy, confectionary, meats, seafoods, pet foods, beverages, snack foods, frozen foods, fruit, vegetables and nuts.

Quality stainless belts for the food industry are solid, continuous, smooth and seamless and free of links, hinges, pins, weaves or anything that could trap food residues, dirt and bacteria.

Textured Stainless Brings Increased Efficiency

Case Study 1 - GP Graders
Melbourne-based GP Graders has captured the attention of fresh fruit packers around the world with its innovative grading and packing lines which utilize textured stainless by ASSDA member Rimex Metals.

Its machines, exported to the US, Chile, Switzerland, Norway, Turkey and Spain, are predominantly fabricated from stainless steel sheet and square tube, incorporating textured stainless steel sheet.

Rimex textured 6WL is used under flat conveyor belts and in ‘dead’ areas to reduce friction (wet belt adhesion) and eliminate product build up. The increased rigidity has enabled the company to reduce sheet thickness and fabrication time, which previously required labor-intensive friction reduction techniques. The end result is a lighter and more cost effective product.

GP Graders was established in 1963 to design and manufacture grading and packing equipment for the cherry, pome fruit, citrus, stone fruit and mango industries.

Case Study 2 - Tripax Engineering
Melbourne-based Tripax Engineering has been a major supplier of industrial food processing machinery in Australia for over 30 years, servicing the fresh vegetable, fruit, salad, potato, cheese, cereal/snack food, and frozen food industries and more.

Its diverse client profile ranges from large multinationals to small vegetable growers, and current export markets include the UK, New Zealand, South Africa, and Denmark.

The majority of equipment is purpose designed and manufactured. During the design process, special attention is paid to matching the type of stainless to the product type, whether sticky, wet, powdery, warm and so on. Rimex textured 6WL pattern is often selected for its low adhesion which reduces the chance of product build-up. It also provides extra strength and rigidity in vibratory conveyor equipment.

From washing equipment for the salad industry, to cheese shredders, abrasive peelers and cutting equipment, all Tripax equipment is made to food industry standards and incorporates high-grade stainless steel, food grade plastics and ancillary parts.

Serving the Australian Food Industry
The multiple benefits of stainless belt technology have assisted the development of new food products and will doubtless continue to do so.

As well as making the stainless belts, Sandvik Process Systems also designs, builds and services complete steel belt equipment. In parallel, within Australia, services in stainless steel belt technologies are available from Process Systems Services (PSS) in Sydney and Industrial Marketing Services in Melbourne, with the former having design, light fabrication and maintenance capabilities. Rimex Metals textured product is distributed by ASSDA member Fagersta Steels.

Words by Russell Jackson and Neil Lyons.

Image on left courtesy of Sandvik Steel.

This article featured in Australian Stainless magazine - Issue 25, July 2003.