Vibro Sifter or Russel sifter is used in pharmaceutical industries for sifting or sieving process.It is one of the most commonly used equipment for sieving of active pharmaceutical ingredients & excipients during the process of wet granulation,dry granulation and direct compression.
Working Principle Of Vibro Sifter
Vibro Sifter or Russel sifter works on the principle of vibratory or gyratory motion.
Material Of ConstructionÂ
The vibro sifter or Russel sifter is made of stainless steel grade 316L.
Components Of Vibro Sifter
A vibro sifter have following components,
- Pneumatic Conveying System
- Reservoir Tank
- Sieving Chamber
Sieving chamber consists of following,
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- Sieves
- Bouncing Balls
- Ball Retaining Ring
- Ball Holding Tray
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- Discharging Chute
- Overflow Chute
- Seals and ClumpsÂ
- Spring & Motor
Pneumatic Conveying System
A vacuum transfer pipe is used to transfer the materials to be sieved from container to the product holding reservoir.
Reservoir Tank
Reservoir container or tank is a stainless steel container which is attached on the upper portion of the sieving chamber.Materials to be sieved are transferred in this reservoir tank.
A butterfly valve is attached to the lower side of the reservoir from where product is delivered to the sieving chamber during the process of sieving.
Sieving Chamber
Sieving chamber is the hollow structure where the main process of sieving or sifting takes place.
The sieving chamber consists of following,
- Sieves
- Bouncing Balls
- Ball Retaining Ring
- Ball Holding Tray
Sieves
The sieves of vibro sifter are round shaped and a suitable sieve is installed in the sieving chamber depending upon the sieve mentioned in BMR or batch manufacturing record.
Bouncing Balls
Bouncing balls are made of food grade material and are placed in a sieving chamber to enhance the impact of vibrations.
Ball Retaining Ring
Specially designed rings are used to retain the bouncing balls during the process of sieving or sifting.
Ball Holding Tray
It is a round perforated structure of stainless steel on which we place the rings containing balls during the process of sieving or sifting.
Discharging Chute
Discharging chute is attached to one side of the sieving chamber.The sieved material passes through the discharging chute & is collected in the product collection containers.
Overflow Chute
Like discharging chute, the overflow chute is also attached to the sieving chamber.The material in form of lumps or the material which is not sieved is collected through this chute.
Seals and ClumpsÂ
Various types of seals made of food grade material & stainless steel clumps are also the part of russell sifter for fittings.
Spring & Motor
Large size stainless steel springs are attached to the base of vibro or Russell sifter.A motor is also attached to the lower end & vibrations are produced when we turn the motor On.These vibrations are transferred to the sifter through the springs.
Working Of Vibro Sifter
- The materials to be sieved are transferred to the reservoir tank of the Russel sifter using a pneumatic conveying system.
- When the reservoir is full,turn the motor On & material will flow from the reservoir tank to the sieving chamber.
- The flow of powder is controlled by a butterfly valve attached at the lower side of Russel sifter or vibro sifter.
- When the valve is opened,the material falls over the sieve in the sieving chamber & is sieved under the effect of vibrations produced.
- The bouncing balls continuously strike with sieve due to vibrations & the material after sieving is collected in a container through discharging chute.
Drawbacks Of Vibro Sifter
The vibro Sifter is not suitable for sieving or screening of those materials which have hard lumps because there is no mechanism in the vibro sifter to break the hard lumps.
The fluffy materials or those which have poor flow are difficult to screen through vibro sifter because their flow from reservoir to the sieving chamber is hindered.
Note
If a vibro sifter is required for sieving purposes then it has only one sieve & one sieving chamber.
If it is required for particle size separation then it has the option for multiple sieves installation with multiple sieving chambers.