Tokyo Institute of Technology

Kyb Corporation

Toshiharu Kagawa

Kenji Kawashima

Yoshinari Nakamura

Kiyokazu Nagata

Chongho Youn

Tomonori Kato

A poppet valve is provided with a seat portion which has a conical inner peripheral surface with a center axis, and a conical portion which is displaced along the center axis inside the seat portion, forms a flow passage having an annular cross-section between the conical portion and the seat portion and is supported at a position concentric with the seat portion. An effect of rectifying fluid flowing in the flow passage is thereby obtained and the generation of noise is prevented.

Poppet valve

A pressure regulator for controlling pressure with high response and high accuracy even a flow change occurs on the downstream side. The pressure regulator () regulates the rate of inflow into an isothermal pressure vessel () for the gas supplied from a gas supply source () by means of a servo valve () to maintain the constant pressure in the isothermal pressure vessel (). Pressure control means (a computer ()) operating the servo valve () has as a main loop a pressure control system for feedback-controlling the pressure in the isothermal pressure vessel () measured by a pressure gauge () and has therein a rate-of-inflow-control system for feedback-controlling the rate of flow measured by a flow meter (), an observer for estimating the rate of outflow from the isothermal pressure vessel () according to the rate of inflow and the derivative of the pressure in the isothermal pressure vessel () measured by a pressure differentiator (), and a model follow-up control system for feed-backing the estimated rate of outflow to the rate-of-inflow control system.

Pressure regulator

An object of the invention is to provide a pressure differentiator capable of improving measurement accuracy. The pressure differentiator of the invention includes an isothermal pressure vessela narrow tubefor connecting an object to be measured to the inside of the vesseland a differential manometerfor calculating a differential pressure between the object and the inside of the vesselIt is preferable that a flow through the narrow tubeduring measurement is a laminar flow. The isothermal pressure vesselis fitted with a temperature equalizing material. As the temperature equalizing material, thin metal wires may be used. When the pressure Pto be measured within a vessel positioned below is changed, the pressure Pwithin the isothermal pressure vesselis changed, with a slight lag, through the narrow tubeBy measuring the differential pressure P(=P&#x2212;P) at that time, using a diaphragm-type pressure differentiator, the derivative value of the pressure Pmay be calculated.

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Yokohama, Japan

Toshiharu Kagawa