Filter Plate Reference Information

Technical information established by EnviroTech Molded Products is provided to help customers obtain performance of filter plates. While exceeding these parameters may not cause immediate plate failure, you will see a reduced service life of the filter plates. The total effect of operating outside of these recommendations depends on the frequency and the amount the recommendations are exceeded. In order to prevent damage and achieve the maximum service life of EnviroTech filter plates, all recommendations should be reviewed and understood before operating the filter plates.

If you have questions regarding the suitability of polypropylene or other thermoplastic in an application, please complete a Process Data Form and return it to EnviroTech Molded Products. This will allow EnviroTech Molded Products to review the application and identify any problems with material compatibility or operating parameters that may be outside the design limits of the plates.

Dimensions shown on the Specification Sheets in this manual are for plates molded in Polypropylene. Because there is a difference in the shrinkage rates between Polypropylene and other thermoplastic materials, the dimensions of plates molded in these materials will be slightly larger or smaller than the dimensions shown on these specification sheets. The variation will be approximately 0.005" to 0.010" per lineal inch of the plate dimension ( i.e., 48.25" x 1.010 = 48.73"). Contact EnviroTech Molded Products for information on the specific change in plate dimensions for plates molded in other thermoplastic materials.

Most applications are suitable for use with polypropylene plate; however, there are some applications which are too aggressive for polypropylene. Typically solutions which contain hydrocarbons (solvent or oil based) should be avoided. EnviroTech Molded Products can offer plates molded in other materials which will be suitable in severe or harsh chemical, pressure or temperature applications.

Chemical composition and temperature have an effect on the allowable maximum operating pressures and temperatures. Pressure/Temperature Charts and Chemical Guides are provided for reference only and any specific applications should be reviewed with EnviroTech Molded Products before making a final selection of plate style, materials and operating conditions. EnviroTech Molded Products warranties its products for material and workmanship and does not warranty any products for chemical compatibility.

The failure mode for polypropylene in compression is creep (deformation). Creep or permanent deformation is a function of time, temperature and stress. Excessive compression loading will cause plate damage and the plates will deform and mushroom around the edge of the plate, causing the plate to become thinner at the periphery.

If the compression force on the seal surface of the filter plate will exceed recommended guidelines, it is recommended that pressure modulation on the hydraulic system be used; i.e., the Press closing force on the plate stack should be ramped up as the feed pressure increases.

Where elevated temperatures are involved, it is also critical that the hydraulic system relief must be set properly to avoid over pressurization due to thermal expansion. Without a properly set relief valve , thermal expansion will cause the plates to expand and excessive compression loading can occur.

The manufactures of PVC and CPVC piping have stated that these materials are not suitable for pressurized air service. As these materials are commonly used for Filter Press liner pipe and piping systems, we caution users that if air is used for cake blowing, core blowing or other applications, PVC and CPVC piping should not be used as liner pipes or in the piping system. If air service is required, Metal or ABS plastic piping can be used.