JPH037785Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of an ultrasonic flowmeter, more specifically, an ultrasonic transmitter suitable for use in an ultrasonic flowmeter in which the fluid to be measured is a high-pressure gas. .

A fluid flow path to be measured is narrowed, ultrasonic transducers are placed opposite each other, and ultrasonic waves are transmitted and received between the ultrasonic transducers through the fluid flow path to measure the flow rate of the fluid passing through the fluid flow path. Ultrasonic flowmeters designed to do this are well known.

The figure shows an example of an ultrasonic transmitter suitable for use in an ultrasonic flowmeter such as the one described above. 3 is a coupling shaft for coupling the cone member 2 to the center of the bimorph oscillator 1; 4 is a coupling shaft for coupling the bimorph oscillator 1 to the center of the bimorph oscillator 1; a cylindrical support member for supporting on a surface opposite to the surface on which the bimorph vibrator 1 is attached, 5 an elastic adhesive for fixing the vibration node of the bimorph vibrator 1 to the end of the support member 4; 6' is an electrode terminal, 7,
7' is a lead wire electrically connecting the electrode terminals and the bimorph resonator, and as is well known, the resonator 1 is activated by applying a pulse or alternating voltage between the electrode terminals 6 and 6'. The device generates ultrasonic vibrations and effectively radiates the vibrations through the cone member 2. The above-mentioned ultrasonic transmitter has low mechanical impedance because it uses a bimorph piezoelectric vibrator, and because it uses a cone member, it cannot effectively emit the vibrations of the vibrator. However, the above ultrasonic transmitter is designed to emit the generated ultrasonic waves into air at normal temperature and pressure, so there is no need to worry about emitting ultrasonic waves into high-pressure gas. This is not taken into account, and as a result, when trying to measure the flow rate of high-pressure gas using the ultrasonic transmitter described above, the cone member that is the vibrator will vibrate in the high-pressure gas, and in that case, If the support member 4 side of the bimorph vibrator 1 is at atmospheric pressure, the difference in pressure acting on both sides of the bimorph vibrator 1 will be very large. In other words, a large pressure acts on the surface facing the high-pressure gas A, which is the fluid to be measured, and a small pressure acts on the surface facing the atmospheric pressure B, so there is a large pressure difference between the two surfaces, and in this state, the transducer 1 If an attempt is made to vibrate the vibrator 1, the vibrator 1 will be damaged.

The present invention has been made in order to solve the above-mentioned problems. For example, as shown in the figure, a communication hole 8 is provided in the support member 4, and thereby the support member of the bimol type piezoelectric vibrator 1 The pressure on the fourth side is made equal to the pressure of the high-pressure gas to be measured, thereby making it possible to use the bimorph piezoelectric vibrator in an ultrasonic flowmeter that measures the flow rate of high-pressure gas.

[Brief explanation of drawings]

The figure is a configuration diagram for explaining an embodiment of an ultrasonic transmitter according to the present invention. DESCRIPTION OF SYMBOLS 1... Bimorph piezoelectric vibrator, 2... Cone vibrating member, 3... Coupling shaft, 4... Vibrator support member,
5... Adhesive, 6, 6'... Electrode, 7, 7'... Lead wire, 8... Communication hole.

Claims (1)

[Scope of utility model registration request] It has ultrasonic transducers narrowly placed opposite to each other in a fluid channel through which high-pressure gas, which is the object to be measured, is flowing, and transmits and receives ultrasonic waves between the ultrasonic transducers to reduce the high pressure flowing through the fluid channel. In an ultrasonic high-pressure gas flowmeter that measures the flow rate of gas, the ultrasonic transmitter includes a bimorph vibrator and a cone member disposed on one surface of the vibrator in contact with the high-pressure gas to be measured; a support member that supports the vibrator on a surface opposite to the surface on which the cone member is disposed, such that the surface of the vibrator on the support member side receives the pressure of the high-pressure gas to be measured; An ultrasonic transmitter in an ultrasonic high-pressure gas flowmeter, characterized in that it is configured as follows.