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Renin Angiotensin Mechanism.

Plate and frame filter press

 

Plate and frame filter press:

Principle:

  • Mechanism is surface filtration.

  • The slurry enters the frame by pressure and flows through the filter medium.

  • The filtrate is collected on the plates and sent to the outlet.

  • A number of frames and plates are used so that surface area increases and consequently large volumes of slurry can be processed simultaneously with or without washing. 

Construction:

  • It consists of plates and frames. 

  • The frame is open and is used as an inlet for the material to be filtered. 

  • Plate has a grooved  surface which gives support to the filter cloth. 

  • The plate and frame may  be made of various metals which provide resistance to corrosion or  prevent metallic contamination of the filtrate. 

  • Filter cloth is fitted on each  side of the plate. 

  • The plates and frames are placed alternatively and  fitted in the outer frame of the press. 

  • Each plate acts as a single filtration  unit. 

  • The outlet of each plate is connected to a common outlet pipe.

Working:

  • As shown in the following diagram the filtering liquid enters the frame  under pressure from the feed channel. 

  • The filtrate passes through the  filter medium onto the surface of the plate.

  • The filtrate is collected in the plates from where it is collected through a common outlet pipe. 

  • The cake is deposited in the frames. 

  • The process of  filtration is continued until the frame is filled with filter cake. 

  • When the process is stopped, the frame is emptied and the cycle is restarted.

  • The thickness of the cake can be varied by using frames of different  thickness. 

  • The thickness of filter cake depends mainly on the solid  content present in the filtering liquid and the resistance of filter cake.  

Advantages of filter press:

  1. The filtering media can be used repeatedly.

  2. Operation and maintenance is simple.

  3. It requires less space.

  4. It provides a large surface area for filtration.

  5. Efficient washing of cake is possible.

Disadvantages of filter press:

  1. It is not a continuous process.

  2. It is used where the proportion of solid in the liquid to be filtered is about  5% or less.

  3. The process becomes costlier because a lot of labor cost is required for  washing and replacement of the filter cloth.

  4. Leakage between the plates may take place through faulty assembly.
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