Essa Certified Pressure Filters

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1 PRODUCT BULLETIN Essa Certified Pressure Filters Introducing a new range of Essa Certified Pressure Filters FLSmidth is releasing a new line of plant and laboratory pressure filters. The Essa Certified Pressure Filters will be typically used on mine sites in gold rooms, assay laboratories and other metallurgical test facilities. The CPF015 and CPF035 Certified Pressure Filters are the result of a collaborative project involving FLSmidth metallurgical process specialists and product engineers working with a firm of independent engineers conversant with pressure vessel verification. An independent design verifier was engaged, and the pressure filters have been registered with WorkSafe Western Australia and incorporate world s best practice design features. SAMPLING, PREPARATION AND ANALYSIS Reason for the redesign Pressure filters are identified as pressure vessels A Mines Safety Bulletin No. 125 (attached with this bulletin) issued by the Government of Western Australia Department of Mines and Petroleum (DMP) on 24 September, 2015, identified pressure filters as pressure vessels, stating: Since filter presses work with the filtrate drain always open, some duty holders are operating under the misconception that this type of equipment is not categorised as a pressure vessel (i.e. classified plant). However, to slowly force liquid out, the filter barrel necessarily stores pressure above the filter cake for prolonged periods. In addition, pressure will build if the filtrate outlet becomes blocked and the drain valve is inadvertently left closed. (p.2) The safety bulletin also stated that recent mine site inspections had identified some issues and potential problems with this type of equipment, and listed factors that might contribute to an increased risk of harm. The Western Australian Department of Mines and Petroleum instructed that mines within their jurisdiction operate compliant units. FLSmidth believes that other authorities and regulatory bodies will require the same standard in the future. FLSmidth was alerted about the issue prior to the safety bulletin being released. Even though the whole industry generally accepted that pressure filters weren t classified as pressure vessels, we took the proactive step to conduct an independent review to ascertain whether our units complied with AS 1210: Pressure Vessels. While FLSmidth was confident that its existing design of pressure filters did not pose any safety risks beyond those expected with the operation of this type of equipment, it acknowledged that the equipment being identified as a pressure vessel made it necessary to comply with AS 1210 as soon as possible. Additionally, we made the Product Bulletin: Certified Pressure Filters 2016 FLSmidth :M ENG V2 1

2 strategic decision to ensure the new design range would also comply with the international ASME VIII: Rules for Construction of Pressure Vessels (Division 1). This allows it to be officially used in operating territories other than Australia. We and our design partners created the new design to achieve compliance so that we could confidently offer it to customers. The former design was immediately withdrawn from the market globally and we asked any customers with outstanding orders for their understanding during the delay while redesign and manufacture were taking place. Redesign process The design brief The research and development team s brief for the new range of pressure filters was to design and manufacture a range of laboratory pressure filters that conforms to a recognised pressure vessel standard which is safe, easier to use and conforms to regulatory requirements. The redesign project also allowed the opportunity to improve the design from an ergonomic and safety perspective, meeting current occupational health and safety expectations, as well as productivity expectations. Customer consultation During the period of redesign, the team were effectively given a blank canvas to create something that is world s best practice in pressure filter design, while fulfilling the compliance issues. FLSmidth sought consultation from internal personnel with extensive metallurgical and operational experience, as well as customers, about an improved design to meet all the needs of plants and operators. This took into account ergonomics, safety, ease of use, durability and reduction of contamination. Recommended solution and implementation Rigorous redesign phase The team undertook a comprehensive research, design and development phase which included the following stages: 1. Rigorous design phase and concept development. 2. Conceptual designs evaluated by end users. 3. Prototypes manufactured. 4. Prototypes industrially tested under normal working conditions in commercial laboratories. 5. Design improvements in the areas of ergonomics and functionality made as a result of the user testing. 6. Independent design verifier engaged. 7. Final design of the product. 8. Design registration, production of manufacturing drawings and associated documentation. 9. Manufacture in accordance with AS 1210 and ASME VIII Division 1. Results The current design, which FLSmidth believes will be a market leader, is now compliant with AS 1210 and ASME VIII Division 1. It has been thoroughly reviewed by WorkSafe Western Australia and is registered with the regulatory body (please refer to the attached Letters of Registration from WorkSafe for evidence of compliance with both AS Class 3 and ASME VIII Division 1). The Essa CPF015 Certified Pressure Filter handles a capacity of 15 litres and is designed for general laboratory and plant applications. The larger diameter Essa CPF035 Certified Pressure Filter handles a capacity of 35 litres. It is used for specialised large volume metallurgical test work and similar batch processing. The pressure filters are both floor-mounted and are fabricated almost exclusively using stainless steel materials and fittings, providing both durability and contamination-free operation. FLSmidth is confident that the new design of Essa Certified Pressure Filters is one of the safest and easiest to use pressure filters on the market. FLSmidth looks forward to supplying our customers with this high quality pressure filter in Product Bulletin: Certified Pressure Filters 2016 FLSmidth :M ENG V2 2

3 The highlights of the new design are as follows: Designed and constructed in accordance with AS 1210, which allows it to be used as a pressure vessel (classified plant) in Australia and, in particular, Western Australian mine sites. The ASME VIII Division 1 registration also allows the pressure filters to be used in other global territories. Robust and long lasting: fabricated almost exclusively using stainless steel materials and fittings. Rated to operate under design conditions of 1380 kpa (200 psi) at 50 C: makes filtering fine samples quicker, reducing sample preparation time and increasing productivity. Ease of use: the swing-out barrel is positioned at a suitable height for easy loading and unloading of sample material. All control levers are within easy reach for operator comfort during long shifts. Operator safety: lid clamping wheel is fitted with an interlock mechanism which prevents the wheel from being turned to release the lid while the barrel is still pressurised. Rotating base for loading and unloading: reduces the risk of contamination of the filter cake or loss of sample. Protective spray shield: the base of the barrel incorporates a stainless steel shield that protects the operator from any liquid spray should the bottom seal be broken. Quick access to the filter cake: there is no need to tediously unscrew the base plate as the barrel easily lifts off the filter cake via a simple lever arrangement. Product Bulletin: Certified Pressure Filters 2016 FLSmidth :M ENG V2 3

4 Mines Safety Bulletin No. 125 Subject: Compliance requirements for batch-type pneumatic filter presses used in laboratories Date: 24 September 2015 Background Batch-type pneumatic filter presses are pressure vessels (i.e. classified plant) commonly found on mine sites in gold rooms, assay laboratories and other metallurgical test facilities. They are typically used to remove the liquid fraction from small batches of mineral slurries to produce a damp filter cake, which is further dried before analysis. Although designs vary, most units typically consist of a cylindrical barrel supported in a free-standing frame. The top closure is commonly clamped in place using a bridge bar and manually operated power screw (or pneumatic actuator). The bottom closure supports the filter cloth or metal mesh and includes collector channels directed to a filtrate drain nozzle. Liquid is pressed out of the filter cake using regulated compressed air (typically < 700 kpag), which is fed into the cylinder barrel above the liquid level. The filtrate nozzle is left open to allow the liquid to drain out. Summary of hazard Typical free standing batch type pneumatic filter press for laboratory use. This example has a manually operated top closure. Numerous hazards can arise with this type of equipment, including: uncontrolled release of pressure, liquid and material (from the seals) while the filter is pressurised Postal address: Mineral House, 100 Plain Street, East Perth WA 6004 Telephone: (08) Facsimile: (08) ResourcesSafety@dmp.wa.gov.au wa.gov.au

5 premature seal failure, with the potential for uncontrolled pressure release and loss of containment if seals are not checked for chemical compatibility with the liquid materials being filtered, particularly when tasks change in the laboratory there is an uncontrolled substitution of sealing materials with alternatives not approved by the original equipment manufacturer (OEM) the common hazards associated with the use of compressed air (e.g. air blast, pressure injection), including the generation of noise as compressed air vents through the drain nozzle when liquid is pressed out of the filter cake uncontrolled release of pressure if incorrectly rated hose or fittings are substituted (e.g. water hose instead of air hose) when the compressed air supply connection is not permanently fixed unsecured free-standing filter presses being knocked or pulled over hazardous manual tasks associated with repeated disassembly, assembly and clamping down of the top and bottom closures (e.g. charging with mineral slurry, removal of filter cake, cleaning and maintenance). Contributory factors Since filter presses work with the filtrate drain always open, some duty holders are operating under the misconception that this type of equipment is not categorised as a pressure vessel (i.e. classified plant). However, to slowly force liquid out, the filter barrel necessarily stores pressure above the filter cake for prolonged periods. In addition, pressure will build if the filtrate outlet becomes blocked and the drain valve is inadvertently left closed. Recent mine site inspections have identified many issues and potential problems with this type of equipment. Factors that may contribute to an increased risk of harm include: failure to install and maintain an appropriate safety relief device to protect the vessel in situations where the filter press can be inadvertently over-pressurised proactively inspect and maintain the equipment, instead of running to failure secure air hose connections with locking pins, clips or whip checks adequately secure the filter to the floor or bench provide adequate warning and instruction signs for equipment undertaking ad hoc modifications, such as substitution of seals using incorrectly rated air hoses and fittings replacing corroded barrels with pipe sections of different material or wall thickness fitting additional leverage on the closure capstan and excessive tightening of the top closure, which can increase the risk of failure and uncontrolled pressure release by overstressing the barrel of the filter or bridge piece, or damaging the seals lack of operator awareness of the design pressure or maximum allowable working pressure (MAWP) of equipment (e.g. connecting filter presses to 7, 8 or 10 bar compressed air supplies without checking that the filter press is adequately protected from over-pressure) the corrosion allowance or need to monitor wall thickness when inspecting and maintaining equipment. Mines Safety Bulletin No. 125 Page 2 of 3

6 Actions required Regulatory requirements Duty holders are reminded of the following requirements of the Mines Safety and Inspection Regulations 1995: keep certain records, particularly for registered classified plant [r. 6.25] inspect, operate and maintain pressure equipment in accordance with AS/NZS 3788 [r. 6.26] design, construct and test pressure vessels in accordance with AS 1210 [r. 6.33] register pressure equipment, other than piping, that has a hazard level of A, B, C or D according to AS 4343 with the State Mining Engineer before it is used on a mine site unless it is already design registered with another statutory authority in Australia [rr. 6.34(1) and 6.34(5); General Exemption dated June 2013] inspect registered classified plant using a competent person appointed under section 44 of the Mines Safety and Inspection Act 1994 keeping records of such inspections in a classified plant record book for general pressure vessels, inspecting at intervals no greater than three years [r. 6.40; General Exemption dated December 2003]. Safe systems of work Duty holders who operate this type of plant need to confirm the plant is included on the site s classified plant register so it can be managed accordingly. Undertake a task-based risk assessment for each laboratory task, and generate appropriate safe working instructions for each application where this type of equipment is utilised. Review the risk assessment whenever there is a change of use. Training and assessment Train and assess operators and maintainers in the safe use and maintenance of this type of equipment, and provide suitable information and instruction. Further information Visit for information on general exemptions. AS/NZS 3788 Pressure equipment In-service inspection AS1210 Pressure vessels AS 4343 Pressure equipment Hazard levels This Mines Safety Bulletin was approved for release by the State Mining Engineer on 24 September 2015 Mines Safety Bulletin No. 125 Page 3 of 3

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