Skip to main content

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.
Labels:

Popular posts from this blog

Rate of Drying Curve.

  Definition Drying is defined as the removal of liquid from a product usually with application of heat. Rate of Drying Curve. Drying process can be divided into three periods Initial Adjustment Period. Constant drying rate period. First falling drying rate period. Second falling rate period. Initial Adjustment Period (A-B): Also called the “ Heating up” period . In this period the substance gets heat and increases in temperature. Drying has not yet started. Constant drying rate period (B-C): During this period the temperature of the solid and the rate of drying remain constant. The moisture evaporating from the surface is replaced by water diffusing from the interior of the solid at a rate equal t o the rate of evaporation.  The moisture content at the end of constant rate (point C) is referred to as the critical moisture content (CMC).  At CMC, dry spots start appearing and drying rate starts falling . First falling drying rate period (C-D): This period is also called ...
Read more

Heat Exchangers and Heat Interchangers.

  In pharmaceutical industries many types of equipments are used for transfer of heat, they can be classified as follows, Heat Exchangers. Heat Interchangers. Heat Exchangers: These devices are used for transferring heat from a fluid (Hot Gas or Steam) to another fluid (Liquid) through a metal wall. Heat Interchangers: These devices are used for transferring heat from a One liquid to another liquid or one gas to another gas through a metal wall. HEAT EXCHANGERS; The equipment used for heat transferring are known as heat exchangers. Some of the processes that involves heat transfer in pharmaceutical industries are: Preparation of starch paste (in steam jacketed kettle). Crystallization. Evaporation. Distillation.  Classification of heat exchangers On the basis of transfer of heat, heat exchangers are classified as: Direct transfer type:  The hot and cold fluids are separated by a metal wall through which the heat is transferred from hot fluid to cold fluid. E.g. shell and ...
Read more

Flash Distillation.

  Principle: When a hot mixture is allowed to enter from a high-pressure zone into a low pressure zone, the entire liquid mixture is suddenly vaporized. This process is known as flash vaporization .  During this process, the chamber is cooled.  The less volatile fraction is condensed and the more volatile component remains in the vapor phase .  This process requires time, hence liquid and vapor are kept in intimate contact until equilibrium is achieved. Flash distillation is also called equilibrium distillation because separation of two liquids takes place when liquid and vapor phases are at equilibrium. Equipment used for Flash Distillation: Construction: It consists of a pump, which is connected to a feed reservoir.  Pumps help in pumping the feed into the heating chamber.  The heating chamber is heat supplied by steam.  The other end of the pipe is directly introduced into the vapor-liquid separator through a reducing valve.  The vapor outlet...
Read more