High-pressure solution for filter press

To keep filter presses working efficiency, it is important for them to be cleaned effectively. High-pressure modules from Cat Pumps can be customised and can save energy consumption and wear, writes Brian Hubbard

With environmental legislation imposing even tighter restrictions on the treatment of industrial wastewater, effective filtration is increasingly being seen as an essential part of the overall treatment process.

In order for filter presses to satisfy the purpose for which they are designed, to separate solids from liquid and form a filter cake, each filter cloth has to be capable of allowing the optimum level of filtrate to pass through during each operating cycle.

The creation of a high-quality filter cake, in other words one that has a high solids and extremely low liquid content, is largely dependent on the effectiveness of the filter cloth. If the filtrate is unable to pass through the filter cloth, then the cake will retain more moisture than is desirable.

This means that periodically the filter cloths within the press have to be thoroughly cleaned, for clean cloths result in a better-quality filter cake and filtrate. In addition, regular cleaning will help to extend the operating life of the filter cloth.

The process of creating a filter cake involves pumping wastewater slurries into the chamber of the filter press, where the filtrate is forced through the filter cloth. The solids are collected on the filter cloth forming a cake, which is allowed to build up until the chamber is full of dewatered solids.

At the end of the cycle, the cake and filtrate are removed and cleaning takes place. Effective washing is best achieved by using an integral, automated spray arm system, with the cleaning water being applied at high pressure.

In order to enable manufacturers of filter presses to attain the highest levels of cleaning efficiency, Cat Pumps offers a Wash Module, based on its high-pressure positive-displacement pump systems.

High-pressure washing increases filter press efficiency by cleaning particulates, fats, oils, proteins and other hard-to-remove residues from the cloth, opening the weave to increase water throughput. Automatic cloth-wash systems are faster than manual washing, reducing out-of-commission downtime and improving consistency of cleaning.

Cat Pumps’ customised high-pressure pump modules for filter presses typically incorporate pressure regulator valve, safety valve and diverter valve, which offloads the pump during idle times, reducing energy consumption and pump wear.

Customers can also use the option of integral 316SS high-capacity overhead supply tank and water intake filter, which protects the pump and prevents blockage of the spray nozzles.

Cat Pumps takes responsibility for water feed to pump level control and low pressure returns to tanks from valves. The company’s positive displacement pumps provide rates of up to 360l/minute and pressures up to and exceeding 100 bar. Furthermore, there are options to ensure that systems conform to ATEX and API specifications for hazardous areas.

According to the company, the field-proven reliability and durability of Cat Pumps’ triplex positive displacement plunger pumps, ensures that high volumes of pressurised wash-water are available on demand whenever required. The most popular models offered for this application are the 3545, delivering up to 210l/minute, and the 6767, delivering up to 285l/minute.

Higher flow rates are available, either from a single larger pump or using two smaller pumps in tandem.

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