Horiba Stec, Co., Ltd.

S-tec Corporation

Masao Yamaguchi

Kentaro Nagai

Hiroshi Mihira

Noriyuki Kimura

Mitsuzo Shimomura

Kouichi Ishikawa

Shigeyuki Hayashi

Yuki Tanaka

Yuji Yamaguchi

Kazuhiro Matsuura

Yasuhiro Isobe

Yukimasa Furukawa

Osamu Horinouchi

Toshiyuki Himi

In order to restrain generation of a peak in the measured flow rate, a fluid control unit measures a flow rate of a fluid in a channel and outputs a signal indicating a valve operation amount of a fluid control valve obtained based on a deviation between a preset flow rate and a measured flow rate and a control coefficient, and the control coefficient for a stable state and the control coefficient for a transitional state are so set to moderate fluctuation of the valve operation amount to the deviation more in the transitional state than in the stable state. At or shortly after a timing when the stable state is switched to the transitional state, a signal is output that indicates an operation amount for a switching time calculated based on each of the operation amounts output at a plurality of timings in the stable state.

Fluid control unit and program storage media for fluid control unit

A flow rate control apparatus is provided which enables high speed response particularly in a transient response state, such as when a target flow rate falls. The flow rate control apparatus includes: a valve provided with a position sensor to measure an opening degree and disposed in a flow channel; a flow rate sensor disposed upstream of the valve and provided with a restrictor; a first pressure sensor disposed downstream of the restrictor and disposed upstream of the valve; a second pressure sensor disposed downstream of the valve; a storage section to store a characteristic map indicating a relationship between at least the opening degree of the valve, a differential pressure before and after the valve, and a flow rate of a fluid passing through the flow channel; and a valve control section to control the valve so that the flow rate reaches an accepted target flow rate.

Flow rate control apparatus and program recording medium having recorded therein program for flow rate control apparatus

A diagnostic mechanism includes: a flow rate control part configured to control an opening degree of a flow rate control valve provided in a flow passage so that a measurement flow rate value outputted from a flow rate sensor becomes a target flow rate value; an inspection value output part configured to output an inspection value related to a time integral of the measurement flow rate value in a diagnostic period which is defined in correspondence with a part of a period from a time point of closing the flow passage upstream of the flow rate sensor to a time point of expiration of a state that the measurement flow rate value and the target flow rate value are substantially nearly equal; and a diagnosing part configured to compare the inspection value and a predetermined specified value to diagnose whether an abnormality relating to the flow rate sensor is present.

Diagnostic mechanism

In order to improve a measurement accuracy of a mass flow meter, the mass flow meter comprises a flow rate calculating section that obtains an output signal from a sensor section having a thermosensitive resistive element arranged in a flow channel where a sample gas flows and that calculates a flow rate of the sample gas, a pressure measuring section that measures a primary side pressure in the flow channel, and a flow rate correcting section that corrects the measured flow rate obtained by the flow rate calculating section by the use of the primary side pressure obtained by the pressure measuring section and a gas coefficient determined by an isobaric specific heat of the sample gas.

Mass flow meter and mass flow controller

The output from the sensor detecting the flow rate of the fluid passing through the conduit is compared with the ceiling value and the appointed compensating signal is added to the output from the sensor to display the signal obtained on the basis of this addition result as the value of flow rate or reduce the openness of the control valve on the basis of the above described signal when the output from the sensor is larger than the threshold value, so that the mass flow meter can accurately display the flow rate even when the fluid passes in an excessive flow rate. In addition, even though the mass flow meter and the mass flow controller are fallen into the abnormal operating condition due to an excessive flow rate of fluid, they can be quickly returned to the normal operating condition.

An improved mass flow controller can be connected to a passageway of a fluid, and can utilize a sensor unit for measuring a characteristic of the mass flow, and deriving a corresponding flow rate signal. Supplemental condition sensors can measure other parameters of the flow rate independent of their utilization in determining the actual flow rate, and can monitor and compare the current value of these sensor conditions, with standards to thereby monitor the operational performance of the mass flow controller.

Mass flow controller with supplemental condition sensors

A part of a tube, through which a fluid passes, is cooled by means of an electronic cooling element and a flow rate of the fluid is measured on the basis of a temperature of a surface of the tube cooled. Not only can the flow rate of the liquid flowing through the tube be determined in a noncontacting manner and a very small flow rate of the liquid be determined, but also the tube is cooled so that no bubbles are generated, and thus the measurement of the liquid, which is apt to generate gases, such as low boiling point liquid, is possible. In addition, the measurement is not influenced by the gases dissolved in the liquid and merely the temperature difference resulting from the flow of the fluid, that is, the rise of the temperature of the fluid, is detected to prevent the measurement from being influenced by the installing posture of the flow meter, so that a highly accurate measurement is possible. Consequently, stable and sure controlling flow rate of liquid is possible.

Flow meter for measuring fluid flow with multiple temperature sensors

A part of a tube, through which a fluid passes, is cooled by means of an electronic cooling element and a flow rate of the fluid is measured on the basis of a temperature of a surface of the tube cooled. Not only can the flow rate of the liquid flowing through the tube be determined in a noncontacting manner and a very small flow rate of the liquid be determined, but also the tube is cooled so that no bubbles are generated, and thus the measurment of the liquid, which is apt to generate gases, such as low boiling point liquid, is possible. In addition, the measurement is not influenced by the gases dissolved in the liquid and merely the temperature difference resulting from the flow of the fluid, that is, the rise of the temperature of the fluid, is detected to prevent the measurement from being influenced by the installing posture of the flow meter, so that a highly accurate measurement is possible. Consequently, stable and sure controlling flow rate of liquid is possible.

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Kyoto, Japan

Masao Yamaguchi