Process of freeze drying

freeze drying

Freeze drying is a process of water vapours from a frozen silution by sublimation Processing of freeze drying (i) Pre-treatment: This step is done to reduce the volume of the solution to be introduced into the container. The solution is pre-concentrated under normal vacuum tray drying. Sometimes solid or liquid desiccants are also used for … Read more

Fluid bed dryer

Theory Fluid bed dryer Fluid bed dryer: If gas is allowed to flow upward through a bed of solid particles at a velocity greater than the setting velocity of the particles, the particles are partially suspended in the gas stream. The resultant mixture of solids and gas behaves like a liquid and the solids are … Read more

Sintered glass filter

Sintered glass filter

Construction of Sintered glass filter The sintered glass filter is made of borosilicate glass finely powdered, sieved, and particles of the designed size are separated. It is then packed into a disc mould and heated to a temperature at which adhesion takes place between the particles. The disc is then fused to a tunnel of … Read more

What is Membrane filter

membrane filter

Principle of Membrane filter: Membrane filter: (Microfiltration) Fitter the material that can retain large solid particles and other particles liquid passes through a microporous membrane material to separate specific substances under the action of static pressure difference. Construction Membrane filter: Membrane filters are made of thin and flat membranes of cellulose derivates, (eg: cellulose acetate, … Read more

Standards for Sieves


Standards for Sieves 1. Number of Sieves: It indicates the number of meshes in a length of 2.54cm in each transverse direction parallel to wires. 2. Nominal size of aperture: The nominal size of aperture indicates the distance between the wires. It represents the length of the side of the square aperture. The I.P has … Read more

Classification of the grades of powders

Classification of powders according to I.P 1) Course powder: Powders of which all particles pass through a sieve with a nominal mesh aperture of 1.70 mm (No. 10 sieve) and not more than 40.0 percent through a sieve with a nominal mesh aperture of 355 μm (No. 44 sieve) is called coarse powder. 2) Moderately … Read more