Abstract: A dehumidified air generator has a plurality of rotatable absorption columns filled with adsorbents for generating dehumidified air which will be used to dry a plastic material or the like. A directional control valve for switching between adsorbing and regenerating steps in the adsorption columns comprises a slide valve mechanism composed of a stator and a rotor slidably held against the stator. The rotor has a plurality of openings defined therein and communicating with inlet/outlet ports defined in side walls of the adsorption columns through tubes. By rotating the rotor in synchronism with the adsorption columns, the adsorbing and regenerating steps are switched to dehumidify, with the adsorbents, humid air introduced into the adsorption columns through the directional control valve and also to desorb the adsorbents for regenerating them.

Abstract: Drying air to be circulated for drying plastic material is demoistured and heated by one of two separate adsorbing treatment units. When one of the two units is engaged in adsorbing treatment of the drying air, the other unit engages in a desorbing treatment and cooling treatment for regenerating the adsorbent by the use of desorbing high temperature air passing through the unit in a direction reverse to that in which the drying air is passed through the unit. The cooling treatment of the adsorbent after the desorbing treatment is accomplished by the use of a part of the drying air.

Abstract: A filter cake cleaning method in a process for filtering gases containing fine particles, as well as a device for practicing the filter cake cleaning method. A filter cake adhering to a filter cloth is cleaned off by passing an overall amplified high-speed gas flow along the primary or outer side of the filter cloth parallel to the filter cloth surface on which the filter cake forms, the surface serving as the wall of a gas passage. A device emits a jetted stream into a collecting vessel at an open space upstream of a gas passage for entraining gas existing in the collecting vessel and for forming the overall amplified high pressure gas, and is controlled by a single automatic open/close valve. A device provided on the secondary or inner side of the filter cloth for jetting backwashing air can be used in conjunction with the above cleaning operation to enhance the cleaning effect.

Abstract: A process and apparatus for mixing synthetic materials and complemental raw materials in a fixed ratio. The synthetic material is fed under the pressure of its own weight to a mixing vessel through a feed conduit having an opening arranged to feed below the top of the vessel. The opening of the conduit is also arranged such that synthetic material will only feed to the vessel when the materials therein fall below the level of the conduit opening. The complemental raw materials are fed over the top of the materials in the vessel at a mass rate of flow proportional to the mass rate of flow of the materials withdrawn from the bottom of the vessel. The synthetic materials are thereby also fed to the vessel in a fixed ratio to the mass rate of flow of the materials to be withdrawn.

Abstract: A process for mixing synthetic materials and complemental raw materials in a fixed ratio. The synthetic material is fed under the pressure of its own weight to a mixing vessel through a feed conduit having an opening arranged to feed below the top of the vessel. The opening of the conduit is also arranged such that synthetic material will only feed to the vessel when the materials therein fall below the level of the conduit opening. The complemental raw materials are fed over the top of the materials in the vessel at a mass rate of flow proportional to the mass rate of flow of the materials withdrawn from the bottom of the vessel. The synthetic materials are thereby also fed to the vessel in a fixed ratio to the mass rate of flow of the materials to be withdrawn.