Filter mechanism
The filter mechanism is composed of a filter plate, a filter frame, a filter cloth and a press diaphragm. Both sides of the filter plate are covered by a filter cloth. When a press diaphragm is required, a set of filter plates is composed of a diaphragm plate and a side plate. The diaphragm plate is covered with a rubber diaphragm on both sides of the substrate, and the filter cloth is covered on the outer side of the diaphragm, and the side plate is an ordinary filter plate. The material enters each filter chamber from the time hole of the thrust plate, and the solid particles are trapped in the filter chamber due to the pore diameter larger than the filter medium (filter cloth), and the filtrate flows out from the liquid outlet hole below the filter plate. When the filter cake needs to be dried, in addition to pressing with a diaphragm, compressed air or steam may be used to pass through the washing port, and the air stream washes off the water in the filter cake to reduce the moisture content of the filter cake.
(1) Filtering method
The way the filtrate flows out is clear flow filtration and dark flow filtration.
A. Bright flow filtration: a water nozzle is arranged on the lower liquid outlet of each filter plate, and the filtrate flows out intuitively from the water nozzle.
B. Underflow filtration: There is a liquid outlet hole below each filter plate, and the liquid outlet holes of several filter plates are connected into one liquid outlet passage, which is discharged by a pipe connected by a liquid outlet hole below the thrust plate.
(2) Washing method
When the filter cake needs to be washed, there are clear flow one-way washing and two-way washing, dark flow one-way washing and two-way washing.
A. The clear flow one-way washing is that the washing liquid enters sequentially from the washing liquid inlet hole of the thrust plate, passes through the filter cloth and then passes through the filter cake, and flows out from the non-porous filter plate, at which time the liquid discharging nozzle of the orifice plate is closed. In the state, the outlet nozzle of the non-porous plate is open.
B. The clear flow two-way washing is that the washing liquid is washed twice from the washing liquid inlet holes on both sides above the thrust plate, that is, the washing liquid is washed from one side and then from the other side, and the outlet of the washing liquid is the same as the inlet. The direction of the corner, so it is called two-way cross washing.
C. The dark flow unidirectional flow is that the washing liquid enters the perforated plate from the washing liquid inlet hole of the thrust plate, passes through the filter cloth and then passes through the filter cake, and flows out from the non-porous filter plate.
D. The undercurrent two-way washing is that the washing liquid is washed twice from the two washing liquid inlet holes on both sides above the stopper plate, that is, the washing is first washed from one side and then washed from the other side, and the outlet of the washing liquid is diagonal. Direction, so it is also called undercurrent two-way cross washing.
(3) Filter cloth: filter cloth is a kind of main filter medium. The selection and use of filter cloth has a decisive effect on the filtration effect. When selecting, it should be selected according to the pH value of the filter material, solid particle size and other factors. Material and pore size to ensure low filtration cost and high filtration efficiency. When using, ensure that the filter cloth is not flat and the aperture is smooth.