Abstract: A system for calibrating a moisture sensor encompasses a processing unit (341). The processing unit (341) includes a reference data obtaining LCKT (345), a subject data obtaining LCKT (346) and a relationship calculating LCKT (347). The reference data obtaining LCKT (345) obtains reference data, after injecting water-vapor with known concentrations into an analyzer. The subject data obtaining LCKT (346) measures subject data indicating temporal variation of output-responses of a subject sensor element of the analyzer under test. The relationship calculating LCKT (347) compares the subject data with the reference data, and calculates relationships between the output-responses of the subject sensor element and the known concentrations.

Abstract: A method of multistage gas phase polymerization is provided comprising performing polymerization of a feed gas mixture at least containing ethylene gas, an &agr;-olefin gas and hydrogen gas in an upstream fluid bed reactor to thereby produce a polymer powder, recovering the thus-produced polymer powder and performing further polymerization of the polymer powder in a downstream fluid bed reactor, the downstream fluid bed reactor being continuously connected to the upstream fluid bed reactor so that the polymer powder recovered from the upstream fluid bed reactor is introduced into the downstream fluid bed reactor, which method comprises the steps of: recovering polymer powder from the upstream fluid bed reactor, treating the recovered polymer powder so as to lower the content of &agr;-olefin gas and hydrogen gas therein by contacting the polymer powder with a stream of gas comprising ethylene or an inert gas, and introducing the treated polymer powder into the downstream fluid bed reactor.

Abstract: A blower 100 for recycling a powder containing gas or for conducting a cyclone treatment thereof, which comprises a casing of blower body 108 having therein a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side, the above slide or rotational slide part being provided with a noncontacted gas leakproof seal part 166 at a clearance ranging from 0.7 to 2.5 mm. A vapor phase polymerization method is provided which is free from the problem that recycling gas such as unreacted gaseous olefin having been discharged from a fluidized bed reactor is formed into a stringy melt polymer or combined into powder to thereby clog a gas recycling pipe or is entrained to a gas recycling pipe or a distributor plate of a polymerizer to thereby cause clogging.

Abstract: A method for vapor phase polymerization comprises blowing a gaseous monomer from a bottom of a fluidized bed reactor through a distributor plate into the reactor by means of a blower while feeding a solid catalyst into the reactor to thereby form a fluidized bed in the reactor and conducting a vapor phase polymerization to produce a polymer or copolymer, wherein the blower has a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side in a blower body casing, said slide or rotational slide part being provided with a noncontacted gas leakproof seal part at a clearance ranging from 0.7 to 2.5 mm.