JPS5981527A - Liquid pressure measuring sensor - Google Patents

Abstract

PURPOSE:To eliminate a transmission loss of liquid pressure and to improve measurement precision by eliminating the need for an insulating bulkhead. CONSTITUTION:A thin pipe 17 and bellows 13 are filled with nonvolatile liquid which is hard to mix with liquid to be measured and has relatively high visconsity. The charged liquid is held in the filling state by the capillarity of the thin pipe 17 and never flows out. A thin pipe 16 communicating with bellows 12 is open to the air at the other end and the other opening of the thin pipe 17 is linked to a container 23 which contains the liquid to be measured. As the bellows 13 extend according to the liquid pressure, the crystal piece 7a of a crystal oscillator 7 at one end 6a of a pressure transmission lever 6 is compressed and the oscillation frequency of a pressure-frequency transducer including the crystal oscillator 7 varies, so that the pressure of the liquid in the container 23 is detected. Thus, the liquid to be measured is brought into contact with a liquid boundary surface for pressure transmission and the need for an insulating bulkhead is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a new liquid pressure measurement sensor used in water pressure gauges, water depth gauges, etc., and in particular to a crystal oscillator whose oscillation frequency changes when pressure is applied. A pressure transmission mechanism with no transmission loss for the liquid pressure to be measured? ! - A novel liquid pressure measurement sensor is provided.

Back technology and its problems Transducers used as pressure measurement sensors that convert pressure into an electrical signal (frequency) include transducers that use a crystal oscillator whose oscillation frequency changes when pressure is applied; It is used for water level measurement, water pressure gauges, water depth gauges, etc., and its uses are wide and effective.

However, in conventional liquid pressure measurement sensors that utilize this type of transducer, the pressure transmission mechanism that converts the liquid pressure into a mechanical force to the all-quartz crystal oscillator requires insulation to record the pressure of the liquid. There is a core where the partition wall is installed, and for this reason, the insulating partition wall causes a transmission loss to the liquid pressure transmission mechanism, and no matter how devised the partition wall is, the presence of the partition wall has a large effect and the measurement accuracy of liquid pressure cannot be maintained sufficiently. The drawback was that it could not be made higher.

Purpose of the Invention Therefore, the present invention aims to provide a complete liquid pressure measuring sensor that can eliminate the transmission loss of liquid pressure and improve the measurement accuracy by using a conventional method of using an insulating partition wall as a pressure machine. It is.

SUMMARY OF THE INVENTION In order to achieve the object described above, the present invention provides a pressure transmission lever that is swingably supported on a fixed part, and a crystal fixed between one swinging end of the pressure transmission lever and the fixed part. having a piece;
The pressure created by the quartz S element contained in this entire quartz piece is -
a frequency conversion means; first and second bellows each having one end fixed to both sides of the other swinging end of the pressure transmission lever and the curved end attached to the fixed part; and each of the first and second bellows. The first end of the tube is connected to the atmosphere or the liquid to be measured, and the other end is connected to the atmosphere or the liquid to be measured.

Embodiment V Below, the liquid pressure measurement method of the present invention will be explained according to an actual example shown in the attached drawings.

The attached drawing shows a part of the pressure measurement sensor according to the present invention with a cutaway. This lid is closed by screw 3.
It is fixed to the case. A support member ≠ is vertically protruded from approximately the center of the bottom plate α inside the case, and a flexible spring member is provided at the upper end of the support member The protruding fulcrum part B a is connected to the pressure transmission lever B ＼
It is made to be able to swing around the hinge member set.

'-F, both ends of a crystal piece 7α constituting the crystal resonator 7 are connected between one end of the pressure transmission lever O and the bottom of the case opposite thereto by a support member g. Electrodes 10, // are attached to both sides of this crystal piece 7α, and by connecting these electrodes 10, // to an active resistor (not shown) and a tuning circuit, the oscillation frequency is adjusted according to the liquid pressure. A pressure car frequency sand exchanger is constructed in which the pressure changes.

The closed end sides of the first and second bellows /2 and /3 are fixed to the upper and lower surfaces of the other end 1rc of the pressure transmission lever B in such a way that their axes coincide with each other, and the first and second bellows /
The open ends of 2 and /3 are the case / upper girder /b and bottom plate /aK
The slight expansion and contraction of the second bellows/2 or the second bellows/3, which are airtightly fixed, is converted into the movement of the pressure transmission lever B, which rotates around the fulcrum of the spring part 3q, and the movement is transferred to the crystal. The pressure is transmitted above and below the piece 7α.

1fC1 Pipe connecting fittings /≠, /2 are fixed in a penetrating state to the case/upper plate /b and refraction /α to which the open ends of the first and second bellows /2, /3 are fixed, respectively. Each of these connecting fittings /g, /j is formed into a spiral shape */// One end of a thin tube of 6 inches or less /o, /7 communicates with the inside of each bellows 7.2 and /3. It is airtightly connected, and the other end has a seal ring that connects it to an external mechanism. It is fitted with a valve of 01.27. The other end of the above-mentioned capillary tube/B is opened to the atmosphere, and the entire external pressure is introduced into the first bellows/2, so that fluctuations in atmospheric pressure are transmitted to the first bellows/2. It has become. On the other hand, the bent end of the thin tube /7 is filled with the pressure liquid to be measured.
Fixing nut 23 mounted watertight on container 2.2
The capillary tube 17 and the first bellows 22 are fitted so as to be in communication with each other, and are hermetically connected to each other by a seal ring 2/ and a fitting nut 1. For example, if the liquid to be measured is water, use silicone oil with a viscosity of 300 CB or more, such as fluorine oil. The tube is vacuum filled. In addition, the liquid filled in the bellows/3 and the capillary tube/7 retains the filled spindle for the capillary action of the capillary tube/7, and the fl register of the capillary tube/7 is opened into the container 23 of the liquid to be measured. However, the filling liquid is often diverted. This means that the pressure measurement liquid and the pressure transmission mechanism including the bellows/3 are completely isolated, and the pressure of the pressure measurement liquid can be transferred to the bellows/3 without loss.
It means that everything can be communicated.

Next, the operation of this embodiment configured as described above will be explained.

The other end of the thin tube /B that communicates with the bellows /2 of the supply / has a large opening 17, and the thin tube /7 that communicates with the second bellows /3.
The other end of the tube 7 is opened at the other end. When the container 23 is fully filled with the liquid to be measured as shown in the drawing, the pressure of the liquid (for example, water) to be ordered in the container 23 is applied to the other end of the thin tube/7. 'D in the capillary tube /7 acts on the body, the liquid in the tube /7 is pushed out into the second bellows /3 according to the liquid pressure in the container, 23, and accordingly the second bellows /3u
Stretch. At this time, since atmospheric pressure is acting inside the first bellows 7.2 through the thin tube/B, fluctuations in the liquid pressure inside the container due to fluctuations in atmospheric pressure are canceled out, and the liquid pressure inside the container is always corrected. The liquid pressure often acts on the second bellows/3.

When the second bellows/3 expands in response to the liquid pressure in the container 23, the pressure transmission lever B uses the spring part as a fulcrum to receive the entire rotational force in the direction of the arrow shown in the drawing, and this causes one end of the pressure transmission lever B to Crystal piece 7 of crystal resonator 7 on 6α side
α is compressed. When the crystal piece 7a receives the full compressive force, the oscillation frequency of the pressure-frequency converter including the crystal oscillator 7 changes according to the force applied to the crystal piece 7a due to the piezoelectric phenomenon, which causes the liquid in the container 23 to change. It is often detected as pressure.

Also, the liquid pressure in the container 13 decreases, and the atmospheric pressure introduced into the first bellows/2 becomes greater than the liquid pressure introduced into the second bellows/3. The lever O receives the rotating cuff 1 in the opposite direction to the arrow A, and as a result, a tensile force is applied to the crystal piece 7α, and as a result, the piezoelectric effect of the crystal piece 7a causes a pressure-frequency conversion including the crystal oscillator 7. The oscillation frequency of the device will change depending on the liquid pressure.

R1] In the above embodiment, a method is adopted in which the liquid to be measured is brought into direct contact with the liquid interface of silicone oil or the like filled in the Iv (Il pipe) and the entire pressure is transmitted to the bellows. This is superior because pressure transmission loss of the liquid to be measured is eliminated and accurate pressure detection is possible.

In addition, in the above embodiment, one bellows/3 and a thin tube/
Although a case has been described in which pressure medium such as silicone oil is filled in 7, bellows/2 and thin tube/B may also be filled with pressure medium. in this case! This is effective for detecting pressure differences between liquids.

As described above, the liquid pressure measurement sensor of the present invention has a fixed πB
It consists of a pressure transmission lever supported by the K swinging control, a hole crystal piece fixed between one swing end of the pressure transmission lever and a fixed part, and a crystal oscillator including the crystal piece. pressure-frequency conversion means; and one of the pressure transmission levers.
Fix one end to both sides of the 112-way swinging end, respectively, and attach the other end to the fixed part'fc 1st and 1st! one end is connected to the bellows of the first and second bellows, respectively,
([7, It consists of a thin tube whose end is connected to the atmosphere and to the liquid to be measured, and the first and second bellows of the first and second bellows and the above-mentioned pipe are connected to the Since the liquid to be measured is sealed with a liquid that is difficult to mix with, the liquid to be measured can be brought into direct contact with the liquid interface for pressure transmission. In addition to being unnecessary, there is no pressure transmission loss due to the partition wall9, which has the effect of improving the measurement accuracy of liquid pressure.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway end view showing an example of the liquid pressure measuring sensor of the present invention, and FIG. 2 is a front view of its lid. Explanation of symbols/...Case, !・・・・・・Lid, ≠・・
...Support member, O...Spring part, 6...
・Pressure transmission lever, 7...Crystal oscillator,
7a...Crystal piece, 10, //...
Electrode, /2...First bellows, /3...
...λth bellows, /O, /7...tubule. wocr1 officer

Claims (1)

[Claims] (1) It has a pressure transmission lever that is swingably supported by a fixed part, and a crystal piece that is fixed between one swinging end of this pressure transmission lever and the fixed part, and this crystal piece is included. A pressure-frequency conversion means constituted by a crystal oscillator, and a seventh and a first one each having one end fixed to both sides of the other swinging ψ11d of the pressure transmission lever and the other end attached to a fully fixed part. A thin tube 6111 which communicates with the bellows and the first and J bellows at one end and communicates with the pipe or the liquid to be measured is filled with a liquid that is difficult to mix with the regular liquid. Liquid pressure measurement sensor. (,2) The liquid sealed in the bellows and the cooling pipe is a non-volatile liquid with high relative viscosity, such as silicone oil or fluorine oil. Liquid pressure measurement sensor.