The mechanical dehydration method is currently widely used in sludge reduction methods. It can be dehydrated by mechanical dump, consumes less energy, and can work continuously.

Commonly used mechanical dehydrations include band filter, centrifugal dehydration machine, board frame filter, etc., each has its own advantages and disadvantages. Among them, the processing effect of the plate frame pressure filter is good, the water content of the filter cake is low, and the sludge treatment volume is relatively large, which cannot be comparable to other dehydration equipment.

The plate frame filter machine is filled between the mud between the filter plate. The water is squeezed out by extruding the filter plate, and the sludge is filtered through the filter cloth to finally dewater. It is generally composed of a supporting frame, hydraulic cylinder, filter plate, gas supply system, filter cloth rinse system and limit device.

1. What are the aspects of equipment selection?

1. The moisture content of mud cakes. In the squeezing and dehydration process, the plate frame filter machine is more direct, the action time is relatively long, the effect is high, the water content after treatment is less water content, and the income of the income is small.

2. Board frame material. The board frame mainly uses materials that are not easy to deform and have a lighter quality, and can resist high pressure during the squeezing process.

3. ｓｅｌｅｃｔ the filter cloth. The selection of filter cloth mainly requires corrosion resistance, strong tensile strength, and good filtration.

4. Work form. By using hydraulic or aerodynamic form control board frames, its pneumatic noise is greater.

Among them, the choice of filter board and filter cloth is particularly important.

Second, the choice of filter board

The selection of filter plates is very important. Considering the working environment of the filter plate, the sludge contains corrosive substances and has a certain amount of corrosion resistance. Repeatable and impact during the work process. The filter board must have a certain strength and have a certain abrasion resistance.

The current commonly used filter plates are:

1. PP polymer polypropylene is currently the most commonly used. This material is very good for various acid and alkali tolerance, including the strongest hydrofluoric acid, and has good acid resistance. Its working temperature is relatively small, and COD Jun finds its maximum of 70 ° with a maximum of 70 °.

2. PVDF is an organic material with acid resistance and the best temperature resistance. Normal temperature resistance can reach about 150 °, but the alkali resistance is extremely poor.

3. Natural rubber filter board, good elasticity, but poor strength. Especially the diaphragm, the natural rubber is still good.

4. Aluminum filter board, the lightest in the metal filter plate, but the acid resistance is relatively poor.

5, cast iron filter board, heavy weight, poor acid resistance, high temperature resistance. It's just a seal, in fact, it must be made with organic materials, which has certain limitations.

6. Stainless steel filter plate, which is good for acid and alkali, but the price is the largest among all filter plates. The material itself is expensive, and the machine processing time is very large.

Considering that the filter plate must be resistant to acid and alkali, and has a certain strength and wear resistance, stainless steel should be selected.

Third, the choice of filter cloth

In order to enable the filtrate to achieve good filtration speed and effect, it is necessary to choose according to the density, chemical composition, and the filtering process used by the pressure filter object.

Common filter cloths can be divided into polyester, patellar, nylon and cotton according to materials. Polypronia filter cloth is acid -resistant, alkali -resistant and good elasticity, and high strength; polyester filter cloth has good acid resistance; cotton filter cloth resistance high -temperature resistance.

1. During the selection of the filter cloth, you must have a certain tensile strength, and you must not have telescope.

This is due to the large amount of sludge in urban sludge, frequent filtering process, and the use of filter cloth is more frequent, and it needs to be squeezed repeatedly.

2. The filter cloth selected by the filter must have a certain amount of corrosion resistance.

Urban sludge needs to add more additives before processing, such as PAM or limestone, so the sludge after natural settlement has a more complex properties and is generally alkaline.

Filter cloth should meet the requirements of corrosion resistance, high strength, small gap, good water permeability, non -adhesive, long life, etc., and long life should be selected.