Abstract: A fixed outer circumferential wall of a fixed scroll, a movable scroll, and a plate define a suction pressure space configured such that fluid flows from a suction chamber into the suction pressure space. The movable scroll and an opposed wall define a first back-pressure space. The plate and a back-pressure-chamber-defining recess of the opposed wall define a second back-pressure space. A back-pressure supplying groove of the opposed wall is configured to connect the first back-pressure space to the second back-pressure space, thereby supplying the fluid from the first back-pressure space to the second back-pressure space. A discharge hole of the plate is configured to connect the second back-pressure space to the suction pressure space, thereby discharging the fluid from the second back-pressure space to the suction pressure space. At least part of the discharge hole is overlapped with the back-pressure supplying groove in an axial direction.

Abstract: A fixed outer circumferential wall of a fixed scroll, a movable scroll, and a plate define a suction pressure space configured such that fluid flows from a suction chamber into the suction pressure space. The movable scroll and an opposed wall define a first back-pressure space. The plate and a back-pressure-chamber-defining recess of the opposed wall define a second back-pressure space. A back-pressure supplying groove of the opposed wall is configured to connect the first back-pressure space to the second back-pressure space, thereby supplying the fluid from the first back-pressure space to the second back-pressure space. A discharge hole of the plate is configured to connect the second back-pressure space to the suction pressure space, thereby discharging the fluid from the second back-pressure space to the suction pressure space. At least part of the discharge hole is overlapped with the back-pressure supplying groove in an axial direction.

Abstract: An ultrasonic time measurement device measures a propagation time of a measurement wave transmitted from a first sensor to a second sensor. The device includes a transmission circuit that causes the first sensor to repeatedly transmit measurement waves one at a time and a reception circuit that detects reception at the second sensor, of the respective measurement wave transmitted from the first sensor. The device further measures elapsed times for the measurement waves, each of the elapsed times being an elapsed time from a reference time to a reception time of the respective measurement wave received by the second sensor and calculate the propagation time of the measurement wave from the first sensor to the second sensor based on the elapsed times measured by the time measurer.

Abstract: A clamp-on type ultrasonic flowmeter that uses ultrasonic waves for measuring a flow rate of a fluid flowing inside a piping, incudes: an ultrasonic transducer having a wedge on which piezoelectric device is attached. Further, the wedge of the ultrasonic transducer has a positioning recess portion formed on a tilted surface of the wedge, and the positioning recess portion defines a position of the piezoelectric device with respect to the wedge of the ultrasonic transducer when the piezoelectric device is attached thereto.

Abstract: A clamp-on type ultrasonic transducer that uses ultrasonic waves for measuring a flow rate of a fluid flowing inside a piping, the clamp-on type ultrasonic transducer including a temperature measuring unit that abuts against the piping and measures a temperature of the fluid via the piping. Further, an elastic member is provided between a device main body and an upper end of the temperature measuring unit, and when the piping is clamped, while a piping contacting surface of the temperature measuring unit is pressed to the piping, a lower surface of the temperature measuring unit abuts against the piping.

Abstract: A clamp-on type ultrasonic flowmeter that uses ultrasonic waves for measuring a flow rate of a fluid flowing inside a piping, includes an acoustic coupler rubber with a flat-plate structure, which is attached to an ultrasonic transmission-reception surface of an ultrasonic transducer that transmits ultrasonic waves to and receives ultrasonic waves from the piping.