Given the vast number of applications that filter presses are used in and the variables that are associated with filter press filtration, the length of time a filter cloth lasts can vary. The measurement of cloth life is generally expressed in total number of filtration cycles.
In the mining industry, filter cloths typically last 4,000 to 5,000 cycles (400-500 hours of filtration time). In typical industrial wastewater treatment applications, filter cloths typically last 750 to 1,000 cycles (750-1,000 hours of filtration time).
There are a variety of factors like abrasion, velocity, oxidation and heat that can impact the lifespan of a filter cloth. Read on to find out more...
The shape, hardness and structure of the solid particles being filtered can impact cloth life. Irregularly shaped particles with sharp edges can cut the small fibers that make up the fabric of a filter cloth.
Abrasion is a great concern when it comes to filter cloths used in the mining industry since many of the particles being filtered through the dewatering systems are highly abrasive. This is less of a concern in general industrial wastewater treatment since the particles filtered by the dewatering systems are mildly abrasive or not abrasive at all.
The velocity that filtrate flows through a cloth can impact the filter cloth's lifespan, particularly at the beginning of the filtration cycle when fine particulate passes through the cloth openings. High velocity and abrasive particulates (as seen in the mining industry) can cause filter cloth failures, especially around feed and filtrate inlet and outlets.
Most filter cloth fibers are made from polypropylene, which can be deteriorated by strong oxidizing agents. Oxidizing agents include chemicals like chlorine, bromine, fluorine, hypochlorites and peroxides. The speed at which a filter cloth deteriorates depends on the strength of the agent and the length of time it is in contact with the cloth.
UV radiation also impacts the lifespan of filter cloths. Prolonged exposure to sunlight can cause cloth fibers to become stiff and prone to tearing.
The high temperatures encountered in some process applications can lead to premature failure of the filter cloth material because of oxidation. This process of heat aging and deterioration is known as thermal degradation.
Have your filter cloths gone past their usable lifespans? It might be time to replace them. Check out these videos of our very own Dr.D demonstrating how to replace a filter cloth on gasketed and non-gasketed filter plates.
Regularly replacing filter cloths is just one aspect of maintaining a well running dewatering system. Download our FREE guide, FAQ's for Filter Press Process, Operations & Maintenance for more tips and tricks to keep your dewatering system running at optimal performance.