JP2000146930A - Device for measuring fluid dryness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for measuring fluid dryness for easily measuring dryness by widening the range of dryness which can be measured. SOLUTION: A by-pass pipe 2 is provided in the middle of a steam piping 1 through which steam flows, and a measuring container 3 and an opening and closing valve 4 are interposed in the by-pass pipe 2. An ultrasonic echo sounder transmitter 5 and an ultrasonic echo sounder receiver 6 are relatively mounted on the measuring container 3. An oscillator 7 is connected with the ultrasonic echo sounder transmitter 5, and a receiver 8 is connected with the ultrasonic echo sounder receiver 6, and the oscillator 7 and the receiver 8 are connected with an arithmetic controller 9. Also, a pressure detecting means 10 is mounted on the measuring container 3, and connected with the arithmetic controller 9. The arithmetic controller 9 calculates a sound speed in steam from the propagating time of ultrasonic waves from the ultrasonic echo sounder transmitter 5 to the ultrasonic echo sounder receiver 6. Also, the faster the sound speed in steam is made, the lower the dryness of fluid is made, and the higher the steam pressure is made, the higher the dryness of the fluid is made even with the same sound speed according to correlation between the sound speed in steam and the dryness of fluid. Thus, the arithmetic controller 9 calculates and outputs the dryness of the steam from the calculated sound speed and a pressure signal detected by the pressure detecting means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the dryness of a fluid in which gas and liquid such as vapor and refrigerant are mixed.
For example, in various boilers and equipment using steam power, it is necessary to know the moisture content in steam, that is, the dryness indicating the ratio of the mass of dry saturated steam to the total mass per unit volume of the steam flow. This is because the enthalpy of the steam varies depending on the water content. Also, it is necessary to know the degree of dryness of the refrigerant in refrigerators such as refrigerators and air conditioners.

[0002]

2. Description of the Related Art As a conventional fluid dryness measuring device, there is a diaphragm dryness meter for measuring the dryness of steam by using a change in isenthalpy of steam. This is achieved by injecting wet steam into the measurement container through a nozzle, adiabatically expanding (equally changing the enthalpy) into superheated steam, and detecting the pressure on the upstream side of the nozzle and the pressure and temperature in the measurement container. The dryness is measured by using a diagram or a saturated steam table and a superheated steam table.

[0003]

The conventional dryness meter described above has a problem that the range of measurable steam pressure and dryness is limited, and only a part of wet steam can be measured. That is, when the pressure and the dryness of the wet steam to be measured are low, the superheated steam state does not occur after the adiabatic expansion. Therefore, a technical problem of the present invention is to provide a fluid dryness measuring device that has a wide range of measurable dryness and can easily measure dryness.

[0004]

In order to solve the above-mentioned technical problems, the technical means of the present invention is to provide a measuring container to be filled with a fluid and an ultrasonic wave transmitter attached to the measuring container. A fluid dryness measuring device, comprising: a receiver, an ultrasonic wave receiver, and an arithmetic controller for calculating and outputting the dryness of the fluid from the propagation time of the ultrasonic wave passing through the fluid.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A measuring container is filled with a fluid to be measured, and an ultrasonic pulse is transmitted from an ultrasonic transmitter mounted on the measuring container and received by an opposite ultrasonic receiver. The propagation time T of an ultrasonic wave passing through a fluid is represented by T = L, where L is the distance between the ultrasonic transmitter and the ultrasonic receiver, and C is the sound speed in the fluid.
/ C, the sound velocity in the fluid can be determined from this. Further, there is a relationship that the speed of sound in a fluid changes depending on the degree of dryness of the fluid, and the lower the degree of dryness, the higher the speed of sound. Therefore, based on the relationship between the sound speed and the dryness, the dryness of the fluid can be calculated from the calculated sound speed.

As described above, according to the present invention, since the dryness of a fluid is calculated from the propagation time of ultrasonic waves, it is not necessary to bring the fluid into a superheated steam state. Therefore, the range of the measurable dryness is wide, and the dryness can be easily measured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment showing a specific example of the above technical means will be described (see FIGS. 1 and 2). This embodiment is applied to a steam dryness measuring device. A bypass pipe 2 is provided in the middle of a steam pipe 1 through which steam flows, and a measurement vessel 3 is provided in the bypass pipe 2 and an on-off valve 4 is interposed downstream of the measurement vessel 3. An ultrasonic transmitter 5 and an ultrasonic receiver 6 are attached to the measuring container 3 so as to face the ultrasonic transmitter 5. The oscillator 7 is connected to the ultrasonic transmitter 5, the receiver 8 is connected to the ultrasonic receiver 6, and the oscillator 7 and the receiver 8 are connected to the operation controller 9. Further, the pressure detecting means 10 is attached to the measuring container 3 and connected to the arithmetic and control unit 9.

Next, measurement of steam dryness by this apparatus will be described. First, the on-off valve 4 is opened to allow a part of the steam flowing through the steam pipe 1 to flow into the bypass pipe 2.
Then, after each part is sufficiently heated, the on-off valve 4 is closed and the measurement container 3 is filled with steam. Subsequently, the arithmetic and control unit 9 supplies a trigger signal to the oscillator 7 to cause the oscillator 7 to oscillate, thereby supplying an oscillating output to the ultrasonic transmitter 5 and transmitting an ultrasonic pulse. Is received by the ultrasonic wave receiver 6. The reception signal of the ultrasonic wave receiver 6 is supplied from the receiver 8 to the arithmetic and control unit 9. Further, the detection signal of the pressure detecting means 10 is supplied to the arithmetic and control unit 9.

The arithmetic and control unit 9 calculates the sound speed in the steam from the propagation time of the ultrasonic wave from the ultrasonic wave transmitter 5 to the ultrasonic wave transmitter and receiver 6, and detects the calculated sound speed and the pressure detecting means 10. Calculates the dryness of the steam from the pressure signal and outputs it. Here, the sound speed in steam and the dryness of steam have a correlation as shown in FIG. 2, and there is a relationship that the dryness decreases as the sound speed increases. There is a relationship that the higher (P1>P2> P3), the higher the dryness. Therefore, the dryness of the steam can be calculated from the calculated sound speed and the detected pressure.

[0010]

As described above, according to the present invention, the dryness of a fluid can be measured without overheating the fluid by calculating the dryness of the fluid from the propagation time of the ultrasonic waves in the fluid.
The measurable dryness range is widened, and an excellent effect that the dryness can be easily measured is produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a steam dryness measuring apparatus according to the present invention.

FIG. 2 is a diagram showing the relationship between the speed of sound in the fluid and the dryness of the fluid at each pressure used in the steam dryness measuring apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steam piping 2 Bypass line 3 Measuring vessel 5 Ultrasonic wave transmitter 6 Ultrasonic wave receiver 7 Oscillator 8 Receiver 9 Operation controller 10 Pressure detecting means

Claims (1)

[Claims] 1. A measuring container filled with a fluid, an ultrasonic transmitter and an ultrasonic receiver mounted opposite to the measuring container,
A fluid controller for calculating and outputting the dryness of the fluid from the propagation time of the ultrasonic wave passing through the fluid.