JPS5912126B2 - Differential pressure response device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a differential pressure responsive device that detects differential pressure as an electrical signal corresponding thereto.

SUMMARY OF THE INVENTION An object of the present invention is to realize a device of this type that is simple in structure and inexpensive to manufacture.

FIG. 1 is a structural sectional view showing an embodiment of the present invention.

In the figure, 21.22 is a block, and 31.degree. 32 is a diaphragm fixed to the peripheral edge of the outer side surface of the block 21.22 by means such as welding.

This diaphragm 31, 32 and this diaphragm 3
Corresponding waveforms are formed on the outer side surfaces of the blocks 21 and 22 that the blocks 1 and 32 face, and the blocks 21 and
．． The gap between the outer side surface of 22 and the diaphragms 31, 32 constitutes an inner chamber 41,42.

51 and 52 are covers, which are fixed to both sides of the diaphragms 31 and 32 with bolts 60.

Between the diaphragms 31 and 32 and the covers 51 and 52,
Pressure receiving chambers 71 and 72 are configured, and these pressure receiving chambers 71.7
Measurement pressure is introduced into 2 from the outside through pressure guiding holes 73 and 74.

Reference numeral 80 denotes a connecting shaft disposed within the center hole 20 of the blocks 21 and 22, and both ends of the connecting shaft are fixed to the diaphragms 31 and 32.

81 has one end fixed to the connecting shaft 80 and the other end fixed to the flange 8
The end rod is fixed to the blocks 21 and 22 by means of welding or the like through the wires 2 and 2, and is made of a highly rigid material so as not to be flexibly deformed as a whole.

Reference numeral 90 denotes a stress detection section provided within the force rod 81 so as to be integrated with the tip rod.

FIG. 2 is an enlarged view of the vicinity of the stress detection section 90.

In this embodiment, a recess 83 is formed from the flange 82 to the tip rod 81.
Two piezoelectric elements 84 made of the same piezoelectric material are arranged in the recess 83 so that their centers coincide with the center line l of the tip rod 81. By pouring and fixing a sealed body 85 of material, the tip rod 81 and the piezoelectric element 84 are made into an integral structure.

FIG. 3 is a configuration diagram showing an example of a piezoelectric element 84 used in the present invention.

Reference numeral 841 indicates a piezoelectric element material formed into a disk shape, and for example, lithium niobate (LiNb03) is used.

Denoted at 842.843 and 844.845 are semicircular electrodes, which are provided to sandwich the piezoelectric element material 841 from both sides.

FIG. 4 shows an electrical equivalent circuit of the piezoelectric element configured as shown in FIG.
Occurs on 5th.

Since the piezoelectric element having such a structure is electrically composed of two piezoelectric elements made of one piezoelectric material, it has the advantage that it is easy to manufacture and can be made compact as a whole.

In the device configured in this way, the pressure to be measured is
3.74 and into the pressure receiving chambers 71, 72, the pressure within the pressure receiving chambers 71.72 is applied to the diaphragms 31, 32.

Since the diaphragms 31 and 32 are connected to each other via the connecting shaft, the diaphragms 31 and 32 tend to be displaced in one direction in response to the difference in pressure they receive.

The connecting shaft 80 is fixed to the tip rod 81 which does not flexibly deform at approximately the center thereof, so even if the connecting rod 80 attempts to displace, it does not actually displace, and a force corresponding to the pressure difference is applied to one end of the tip rod 81. It will be given to

When a force corresponding to such a pressure difference is applied to one end of the tip rod 81, the tip rod 81 has a structure that does not flexibly deform. 81
Stresses δ are generated with different polarities on the left and right sides around the center line l of , and whose magnitudes correspond to the applied forces.

Here, since the piezoelectric element 84 is located inside the tip rod 81 and has an integral structure with the tip rod 81, it receives stress +δ and -δ generated inside the tip rod 81, and due to the piezoelectric effect, this stress δ is A corresponding voltage V is generated between each electrode.

This voltage (■) is indicated by (12).
If the voltage V generated at 45 is measured differentially, the stress δ
In other words, it is possible to obtain an electrical signal corresponding to the differential pressure.

Furthermore, when the voltage generated between each electrode is measured differentially,
For mechanical vibration noise transmitted to the tip rod 81, 2
Since it acts on the two piezoelectric elements in the same phase, they cancel each other out and are not influenced by them.

FIGS. 5 and 7 are configuration diagrams showing other embodiments of the present invention.

In the embodiment shown in FIG. 5, 10 is a pressure receiving plate having a structure that does not flexibly deform, 71 and 72 are pressure receiving chambers formed on both sides of the pressure receiving plate 10, and 73 and 74 are pressure guiding holes through which measurement pressure is introduced. be.

Reference numeral 91.9□ denotes a stress detecting section provided in the pressure receiving plate 10 so as to be integrated with the pressure receiving plate, and here, two stress detecting sections are provided on the upper and lower sides.

FIG. 6 is a perspective view showing a part of the pressure receiving plate 10 used in the device shown in FIG. F1. F2 acts from both sides.

Therefore, the pressure receiving plate 10 receives the force Fl-F2 and tends to be displaced in the direction of the smaller force.

Here, since the pressure receiving plate 10 has a structure that does not flexibly deform, the force Fl-F2 appears as a stress change inside the pressure receiving plate 10.

This stress change is detected by stress detection sections 91 and 92 that are integrally constructed with the pressure receiving plate 10.

The embodiment of FIG. 7 is different from the embodiment of FIG.
are fixed at both ends to the blocks 21, 22, and the force received by the diaphragms 31, 32 is transferred to the connecting shaft 80.
1 and 802 to both sides of the center portion of the tip rod 81.

In addition, two stress detection means 91, 9□ are provided here.

In either embodiment, the pressure receiving plate 10 is configured so as not to be flexibly deformed, and the stress detection means is configured to prevent the pressure receiving plate 10 from being flexibly deformed.
0, and the stress detection means 9 is integrated with the pressure receiving plate 1.
0 is designed to detect the internal stress.

FIG. 8 is as shown in FIG. 3 as a stress detection means.

FIG. 2 is a connection diagram showing an example of an electric circuit when a piezoelectric element is used.

Here, in the piezoelectric element 84, electrodes 843 and 844 are connected to the common line, and electrodes 842 and 845 are connected to the common line.
A parallel connection is used in which an electric signal corresponding to the stress is obtained from this connection.

In this figure, SW is a switch having contacts a, b, and c, DC is a charge detection circuit, ME is a charge storage and holding circuit, and CK is an arithmetic circuit.

Switch SW is connected to contacts a and c only for a short time, as shown in FIG. 9A.

Now, when the switch SW is connected to the contact point a in a state where the amount of charge Q corresponding to the stress is generated in the piezoelectric element 84, the ninth
A current as shown in the figure flows, and its discharge characteristics are determined by the input impedance of the charge amount detection circuit DC.

Here, the current peak value A1 at the moment when the switch SW is connected to the contact a corresponds to the stress δ1 generated inside the tip rod or the pressure receiving plate.

The electric charge storage and holding circuit ME stores and holds the current peak value A1 as shown in FIG. 9C.

The switch SW is then connected to the contact C, and after discharging the electric charge of the piezoelectric element, is connected to the contact S.

Next, when switch SW is connected to contact a, if stress δ1 has changed from δ1 by +△δ1, a new charge amount corresponding to +△δ1 is generated in the piezoelectric element. Therefore, a current having a current peak value A2 corresponding to +δ1 is detected from the charge amount detection circuit DC as shown in the 11th Shikoku circuit, and is stored in the charge amount storage holding circuit ME.

The arithmetic circuit CK receives signals corresponding to each peak value from the electric charge storage holding circuit ME, and can obtain a signal corresponding to the differential pressure by calculating these signals.

That is, A2. A3. A4 represents the deviation value from stress δ1, and Alr A2 + A3 +
By sequentially adding and calculating A4, it is possible to obtain an electrical signal corresponding to the absolute value of the differential pressure.

In each of the above-mentioned embodiments, a large number of sets of stress detection means 9 are arranged on the tip rod or the pressure-receiving plate, and these signals are appropriately calculated depending on the stress distribution to obtain electrical signals. You can also do this.

Further, the cross-sectional shape of the tip rod 81 and the shape of the pressure receiving surface of the pressure receiving plate 10 may be any shape such as a circular shape, a rectangular shape, or a circular shape.

In addition, in the embodiments shown in FIGS. 5 and 7, the pressure receiving plate 1
0 may be filled with an incompressible fluid such as silicone oil, and the measurement pressure may be applied to the pressure receiving plate 10 via the incompressible fluid.

As described above, according to the present invention, a differential pressure responsive device with a simple structure and low manufacturing cost can be implemented.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the configuration of an embodiment of the present invention, FIG. 2 is an enlarged view of the vicinity of the stress detection section in FIG. 1, and FIG. 3 is a configuration diagram of an example of the piezoelectric element used in the present invention. Fig. 4 is an electrical circuit diagram of the piezoelectric element shown in Fig. 3, Figs. 5 and 7 are configuration diagrams showing other embodiments of the present invention, and Fig. 6 is a cross-sectional view of a part of the embodiment of Fig. 5. 8 is a block diagram showing an example of an electric circuit, and FIG. 9 is an operation waveform diagram of FIG. 8. 21.22...Block, 31,32...
...Diaphragm, 41.42...Inner chamber, 51
, 52... Cover, 60... Bolt,
71.72... Pressure receiving chamber, 73.74...
・Pressure hole, 80...Connection shaft, 81...
Tip bar, 84...piezoelectric element, 90...stress detection means, 10...pressure receiving plate.

Claims (1)

[Claims] 1. A tip rod or pressure receiving plate that is applied with a force corresponding to the differential pressure and is made of a highly rigid material, two piezoelectric elements that share at least one piezoelectric element material, and these two piezoelectric elements are connected to the piezoelectric The tip rod or pressure receiving plate is arranged so that the center of the element material coincides with the center line of the tip rod or the center line parallel to the pressure receiving surface of the pressure receiving plate, and the stress generated by the differential pressure to be measured is applied to the two piezoelectric elements with opposite polarities. A differential pressure response device comprising a fixing means installed and fixed on a plate, and a means for differentially measuring electric signals generated in the two piezoelectric elements.