A flow rate control device having a high response accuracy is provided.

A flow rate control device includes a flow sensor measuring a flow rate of a fluid, and a controller adjusting the flow rate where the flow rate of the fluid to be a flow rate set value. The controller includes a control valve changing the flow rate, a drive circuit driving the control valve, a sensor response adjustment circuit adjusting a frequency response of a measured value of the flow sensor, and a first filter attenuating a predetermined frequency band of an output of the sensor response adjustment circuit. The drive circuit, the flow sensor, the sensor response adjustment circuit, and the first filter, configure a feedback loop. A deviation between the flow rate set value and an output of the first filter becomes an input to the drive circuit.

In the physical quantity detection device, the occurrence of the measurement error is reduced by suppressing the flow bias in the sub-passage and reducing the resistance in the passage. A physical quantity detection device 30 of the present invention includes a measuring portion 310 disposed in a main passage, a sub-passage 330 that takes a gas to be measured from the main passage, a support member 603 that divides a part of the sub-passage into two flow paths of one surface side and the other surface side in a direction intersecting a passage width direction, and a flow rate detection element 602 disposed on one surface of the support member. The sub-passage includes a straight portion 321 in which the support member is disposed and a downstream curved portion 322 that is curved to one side in the passage width direction of the straight portion. The straight portion is provided with a dividing wall 500 that divides the flow path on the other surface side of the support member into two flow paths on one side and the other side in the passage width direction, and a cross-sectional area of the flow path on one side in the passage width direction is smaller than a cross-sectional area of the flow path on the other side in the passage width direction.

Provided is a thermal flow meter to improve the measurement accuracy of a temperature detector provided in a thermal flow meter. The thermal flow meter includes a bypass passage through which a measurement target gas 30 flowing through a main passage flows, and a circuit package 400 which includes a measurement circuit for measuring a flow rate of the measurement target gas 30 flowing through the bypass passage and a temperature detecting portion 452 for detecting a temperature of the measurement target gas. The circuit package 400 includes a circuit package body which is molded by a resin to internally envelope the measurement circuit and a protrusion 424 molded by the resin. The temperature detecting portion 452 is provided in the leading end portion of the protrusion 424, and at least the leading end portion of the protrusion protrudes to the outside from a housing 302.

Provided is a thermal flow meter to improve the measurement accuracy of a temperature detector provided in a thermal flow meter. The thermal flow meter includes a bypass passage through which a measurement target gas 30 flowing through a main passage flows, and a circuit package 400 which includes a measurement circuit for measuring a flow rate of the measurement target gas 30 flowing through the bypass passage and a temperature detecting portion 452 for detecting a temperature of the measurement target gas. The circuit package 400 includes a circuit package body which is molded by a resin to internally envelope the measurement circuit and a protrusion 424 molded by the resin. The temperature detecting portion 452 is provided in the leading end portion of the protrusion 424, and at least the leading end portion of the protrusion protrudes to the outside from a housing 302.

A flow meter device includes plural fluid passages which are provided between an inlet section into which a fluid flows and an outlet section from which the fluid flows out, and through which the fluid flows and flow value measuring units installed in the plural fluid passages, respectively. The flow value measuring units are configured to measure flow values of the fluid flowing through the fluid passages. The flow meter device further includes a control unit configured to determine whether or not to cause one or more of the flow value measuring units to stop a measuring operation of the flow value based on the flow values measured by the flow value measuring units. The control unit is further configured to determine whether or not to cause the one or more of the flow value measuring units to resume the measuring operation of the flow value, based on the flow value measured by the flow value measuring unit as a monitoring measuring unit which is other than the one or more of the flow value measuring units and is activated to perform the measuring operation of the flow value.

A flow meter device includes plural fluid passages which are provided between an inlet section into which a fluid flows and an outlet section from which the fluid flows out, and through which the fluid flows and flow value measuring units installed in the plural fluid passages, respectively. The flow value measuring units are configured to measure flow values of the fluid flowing through the fluid passages. The flow meter device further includes a control unit configured to determine whether or not to cause one or more of the flow value measuring units to stop a measuring operation of the flow value based on the flow values measured by the flow value measuring units. The control unit is further configured to determine whether or not to cause the one or more of the flow value measuring units to resume the measuring operation of the flow value, based on the flow value measured by the flow value measuring unit as a monitoring measuring unit which is other than the one or more of the flow value measuring units and is activated to perform the measuring operation of the flow value.

An in-line flowmeter for large diameter pipes includes an outer pipe with a diameter equal to that of the pipe to which it is coupled and an inner measuring tube carrying a portion of the flow, the flow through the measuring tube being sensed by a flowmeter associated with the measuring tube and with the total combined flow rate out of the in-line flowmeter calculated from the sensed flow through the measuring tube.

An in-line flowmeter for large diameter pipes includes an outer pipe with a diameter equal to that of the pipe to which it is coupled and an inner measuring tube carrying a portion of the flow, the flow through the measuring tube being sensed by a flowmeter associated with the measuring tube and with the total combined flow rate out of the in-line flowmeter calculated from the sensed flow through the measuring tube.

A gas meter is provided. The gas meter has a gas inlet, a gas outlet and a measuring section. A measuring device for thermal flow measurement can be arranged in the measuring section. A filtering device for removing particulate impurities is arranged downstream of the gas inlet. Gas diverted from the main gas flow is supplied to the filtering device for purifying the gas. After the purification, the purified gas is fed to the measuring device arranged downstream of the filtering device.

A gas meter is provided. The gas meter has a gas inlet, a gas outlet and a measuring section. A measuring device for thermal flow measurement can be arranged in the measuring section. A filtering device for removing particulate impurities is arranged downstream of the gas inlet. Gas diverted from the main gas flow is supplied to the filtering device for purifying the gas. After the purification, the purified gas is fed to the measuring device arranged downstream of the filtering device.