Smc Kabushiki Kaisha

Toru Horiuchi

Kenji Shinozaki

Akio Sato

Kenji Tsukamoto

Kenji Moriyama

The present invention relates to a throttling structure for use in a fluid pressure device. A nozzle passage is formed between a primary side port and a nozzle back pressure chamber. A throttling mechanism made up from a plurality of orifice plates is disposed in the nozzle passage. Small diameter opening holes, which are smaller in diameter than the nozzle passage, are provided in the orifice plates. Outer edge portions of the orifice plates are retained in a second body part via seal members. Further, the orifice plates are separated mutually from each other by a predetermined distance along the direction of extension of the nozzle passage.

Throttling structure for use in a fluid pressure device

A flow rate control valve includes a second substrate having a flexible thin film and interposed between a first substrate having a heating mechanism and a third substrate having a sealing section. The first substrate and the second substrate close an internal space formed adjacent to the heating mechanism and filled with an expandable material. The sealing section and the flexible thin film function together as a valve. The heating mechanism heats and expands the expandable material whose pressure is detected by pressure-detecting sensors. The detected pressure value is fed back to a control mechanism of the heating mechanism for opening/closing a fluid flow passage and controlling the valve opening degree.

Flow rate control valve

The real mass flow rate is calculated for a variety of gases. The variety of gases are classified into a plurality of classifications, and representative discharge coefficient relationships are previously determined for the respective classifications. When an upstream pressure and a temperature are detected for a certain gas on an upstream side of the sonic nozzle, a theoretical mass flow rate is calculated. After the theoretical mass flow rate is calculated, reference is made to a theoretical mass flow rate-discharge coefficient correspondence table recorded in a memory corresponding to the classification of the gas, to determine a discharge coefficient based on the relationship appropriate for the gas type. After the discharge coefficient is selected, a real mass flow rate is determined as a product of the determined discharge coefficient and the theoretical mass flow rate.

Mass flow rate-measuring method and mass flow rate control apparatus

A flow meter for measuring a flow rate of a fluid passing through a fluid passage is provided with a throttle structure disposed at the inside, and it is connected to the fluid passage. The fluid passes through a groove via expanded grooves formed on a surface of a substrate which constitutes the throttle structure. The flow rate of the fluid passing through the fluid passage can be measured by detecting pressures and temperatures of said fluid on an inflow side and an outflow side concerning the throttle structure.

Throttle structure and flow meter incorporated with throttle structure

Disclosed is a self-diagnosis method for a mass flow controller comprising a pressure control valve, a first shut off valve for performing opening/closing operation on an inflow side of the pressure control valve, an orifice disposed on an outflow side of the pressure control valve, a pressure sensor for detecting an inflow side pressure of the orifice, and a second shut off valve for performing opening/closing operation on an outflow side of the orifice. The first shut off valve is in an open state and the second shut off valve is in a closed state while the pressure control valve is in a fully open state so that a previously determined gas having a predetermined pressure is charged via the first shut off valve into a pipework ranging from the first shut off valve to the second shut off valve. Subsequently, the first shut off valve is in a closed state and the second shut off valve is in an open state so that the gas charged in the pipework is allowed to cause outflow. Diagnosis is performed for the mass flow controller on the basis of a period of time required to lower a detection pressure detected by the pressure sensor to a previously determined detection pressure as a result of the outflow. This self-diagnosis process requires no hardware to be newly added, other than hardware necessary for ordinary operation of the mass flow controller.

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Higashimurayama, Japan

Toru Horiuchi