Hoppers, square

Rotary V lve Feeders. Devices known as rotary valve feeders are commonly used for circular or square configured outlets. These are particularly useful when discharging materials to a pneumatic conveying system where a seal is required to prevent air flow through the hopper outlet. The discharge rate is set by the speed of rotation of the vanes or pockets of the valve. 

Microstrainers. Microstrainers are rotating steel screens with extremely fine stainless steel mesh (85—170 perforations per square centimeter (13—26/in. )). The flowing Hquid enters the open end of the dmm and passes through the mesh to the effluent end. The mesh traps soHd impurities and rotates with the dmm. A wash-water spray washes the trapped soHds into a hopper for final disposal. The mesh is washed with filtered effluent discharged from jets fitted into the dmm and then exposed to uv radiation to inhibit microbial growth. The mesh is washed with chlorine water at intervals of 7 to 28 days in order to control slime growth removal efficiencies are 30—55% of the appHed BOD and 40—60% of suspended soHds. 

Hopper, Vincent Foster. Medieval number symbolism. New York Cooper Square Pubis, 1969. 241p. 

Inlet gas uniformity as measured by the inlet root mean square (RMS) should be kept less than 20%. Nonuniform gas flow or maldistribution will result in poor collection, excessive reentraimnent, or hopper sweepage. The precipitator is designed to have very little flow at the bottom of the collection plate to allow the particles to drop freely into the hopper without entrainment back into the gas stream. 

The vee form of hopper, with inclined front wall oriented square to the screw axis, formed two front gullies down which the material would not flow. Material that built up on these gullies provided a steep, large-radius mass of permanent product at each side of the hopper front. 

At its base, the hopper empties into the feed throat through an opening. This opening in the feed throat is often circular or square. However, improved feeding has been measured when the opening is elongated along the barrel direction with dimensions of 1.5 screw diameters by 0.7 screw diameters [7]. 

Large bulk containers are usually square or rectangular in shape and constructed in steel, aluminium, wood or concrete. Unless the container is emptied manually, it may be fitted with a tilting mechanism or its lowest part forms a conical or pyramidal hopper. Hoppers may incorporate shaker devices, filters, and special types of valves for discharging lumpy or moist material and multiple discharge outlets. 

Square feed hoppers with rapid compression usually work well with bulk materials with uniform pellet size. However, when there is a large variation in particle size and shape the square feed hopper is likely to cause conveying problems. This can happen for instance when regrind is added to the virgin material. For this reason it is better to use a circular hopper with gradual compression. 

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