JPS6136391B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a diaphragm, a pressure receiving plate,
It is converted into displacement through the spring material, and this displacement causes
This technology relates to a pressure-electric transducer that deflects the optical image on the photosensitive surface of a light-receiving element and converts it into an electrical signal.The purpose is to develop a technology that comprehensively maintains the following basic performances required of a pressure-electric converter. is to provide.

(a) It has good characteristics even under very small pressures, such as a few mmAg, and can continuously detect whether the sign of the differential pressure to be detected is positive, negative, more negative than positive, or more negative than negative. and the electrical output signal is proportional to the differential pressure.

(b) Good ambient temperature and aging characteristics.

(c) It does not require complicated electronic circuits and can be realized at an extremely low cost.

(d) be free of fragile parts, withstand excessive pressure and impact, and be easy to manufacture;

etc.

Conventionally, position or pressure detection means have used differential transformers, inductance changes, and piezoresistive elements, but these methods require expensive components, require complicated amplifiers, and are easily damaged. There were various difficulties such as difficulty in operating under low pressure. Also, one using one photoconductive cell (CdS),
Some used silicon stress elements (elements whose resistance value changes due to strain), but these all had problems with ambient temperature characteristics and reliability over time.

As described above, the present invention aims to eliminate the drawbacks of conventional pressure-electric converters and provide a pressure-electric converter that is extremely superior in terms of performance, cost, mass productivity, etc.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a structural sectional view of an embodiment of the present invention.
In Figure 1, 1 is a high pressure side case, 2 is a low pressure side case, 3 is a high pressure inlet, 4 is a low pressure inlet, 5 is a diaphragm, 6 and 7 are pressure receiving plates, 8
9 is a rivet for integrating the diaphragm 5 and the pressure receiving plates 6 and 7, 9 is a slit plate fixedly attached to the rivet 8, and 10 and 11 are compression coil springs. The above elements constitute a pressure displacement converter that converts pressure into displacement.

12 is a photoelectric material, e.g., due to the deviation of the optical image.
A light-receiving element in which the ratio of characteristic values of two photosensitive surfaces of the same shape made of CdS, CdSe, silicon, etc. changes differentially; 13 is a light source, such as a light emitting diode, a neon lamp, a filament lamp, etc.; 1
Reference numeral 4 denotes a holding stand for fixing the light receiving element 12 and the light source 13, and is attached to the low pressure side case 2. 15 is a lead terminal of the light receiving element 12, and 16 is a lead terminal of the light source 13. the slit plate 9;
By the light receiving element 12, the light source 13, and the holding table 14,
This constitutes a displacement electrical conversion section. 17 is the slit plate 9
It is a rectangular slit hole provided in the.

In the above configuration, the low pressure inlet 4 is released, the pressure is set to atmospheric pressure Po, and the high pressure inlet 3 is connected to atmospheric pressure.
When the pressure Ps of the detected part, which is higher than Po, is guided through a pipe etc., the difference between the detected pressure Ps and the atmospheric pressure Po becomes a positive value of Ps - Po, and this differential pressure Ps - Po
is applied to the diaphragm 5 and the pressure receiving plate 6, and a receiving pressure of F is applied. Therefore, the diaphragm 5 and the pressure receiving plate 6 move to the low pressure side. However, at this time, the compression coil spring 11 is deflected via the pressure receiving plate 7, increasing the stress, and the compression coil spring 10, which is applying stress to the pressure receiving plate 6, is elongated and the stress is reduced.
Therefore, the diaphragm 5 is displaced to a position where the sum of the stress of the compression coil spring 10 and the received force F and the stress of the compression coil spring 11 are balanced.

Next, when a pressure lower than atmospheric pressure Po is introduced into the high pressure inlet 3, the differential pressure Ps-Po becomes a negative value, and contrary to the above, the diaphragm 5 moves to the high pressure side, and its position is This is the position where the sum of the stress of the coil spring 11 and the received force and the stress of the compression coil spring 10 are balanced.

In the end, the differential pressure Ps between the diaphragm 5 and the pressure receiving plates 6 and 7
-Position relative to Po is two compression coil springs 1
The difference in stress due to deflection of 0 and 11,
It is determined by the magnitude and direction (or sign) of the received force F. Since the slit plate 9 is fixed to the rivet 8 and has the same displacement as the diaphragm 5 and the pressure receiving plates 6 and 7, the slit plate 9
The slit hole 17 provided in the figure also shows the same displacement. Here, the differential pressure Ps-Po is proportional to the received pressure F, and the deflection and stress of the compression coil springs 10 and 11 are also proportional, so the displacement of the slit hole 17 is proportional to the magnitude of the differential pressure Ps-Po. It will be a proportional value.

Next, the light receiving element 12 and the light source 13 are mounted on a holding base 14 facing each other, and the slit plate 9 and the light receiving element 12 are placed in an extremely close positional relationship, so that the light emitted from the light source 13 is Of these, only the light that passes through the slit hole 17 is detected by the light receiving element 1.
The photosensitive surface of the light receiving element 12 is irradiated with light from other than the slit hole 17. Therefore, if the distance between the slit plate 9 and the light source 13 is set appropriately, the distance between the slit plate 9 and the light receiving element 12 is extremely small, and the shape and position of the light image on the photosensitive surface of the light receiving element 12 will be determined by the slit hole 17. The shape and position of Therefore, when the slit hole 17 is displaced, the optical image on the photosensitive surface of the light receiving element 12 is displaced exactly equal to the displacement.
When the optical image on the photosensitive surface of the light-receiving element 12 shifts, as will be described later, the ratio of the characteristic values of two photosensitive surfaces of the same shape made of photoelectric material changes differentially. According to the displacement, the output electrical signal of the light receiving element 12 changes.

In other words, the above-mentioned differential pressure Ps-Po and slit hole 1
Since the displacement of the light receiving element 12 is proportional to the displacement of the slit hole 17 and the electric output signal of the light receiving element 12 changes according to the displacement of the slit hole 17, the electric output signal of the light receiving element 12 is introduced into the high voltage inlet 3 and the low voltage inlet 4. The value corresponds to the difference in pressure applied.

Next, the principle of the light receiving element 12 will be explained based on FIG. In the figure, 18 and 19 are two photosensitive surfaces of the same shape (comb-shaped triangles in the figure) made of photoelectric materials such as CdS, CdSe, silicon, etc., and these are formed on the same substrate. There is. 20, 21, 22 are electrodes, 2
1 is especially a common electrode. L is a light image, and A and B are areas of the light image L irradiating the photosensitive surfaces 18 and 19. When the illuminance of the light image L is appropriate, the ratio of the characteristic values of the part of the photosensitive surface 18 or 19 that is irradiated with the light image L and the part that is not irradiated is extremely large. The ratio of the characteristic values of the photosensitive surfaces 18 and 19 is determined by the ratio of the areas A and B. Therefore, when the optical image L moves in the direction indicated by the symbol X in FIG. 2, the ratio of the areas A and B changes differentially accordingly.
Therefore, we now use e.g. photoelectric materials as photoconductive cells (CdS
or CdSe) and apply a DC voltage Vi (10V) between the electrodes 20 and 22 in FIG. 2 to obtain an output voltage Vo between the electrodes 21 and 22. Due to the movement of the optical image L,
The resistance values of areas A and B change differentially, and the third
As shown in the figure, the voltage is
Vo shows a nearly linear change. That is, in the light receiving element 12, the ratio of the characteristic values of the two photosensitive surfaces 18 and 19 of the same shape made of photoelectric material changes differentially depending on the deviation of the optical image L. Outputs an electrical output signal according to the request.

FIG. 4 shows a pressure-output voltage characteristic diagram of an embodiment of the pressure-electric transducer according to the present invention.

In the configuration shown in FIG. 1, the effective area S of the diaphragm 5 is 32 cm ² , the spring constants of the compression coil springs 10 and 11 are both k = 16 g/mm, the effective stroke l of the light image L is 4 mm, and the displacement of the diaphragm 6 is Since the stress is extremely small relative to the spring constant k, it is ignored. Therefore, the pressure F received by the diaphragm 5 per differential pressure P=Ps-Po=1mmAg is F=1/10S=3.2g/mmAg.

Next, since the spring constant of each of the two compression coil springs 10 and 11 is k=16 g/mm, now,
Assuming that the pressure receiving plates 6 and 7 are displaced 1 mm toward the low pressure side in FIG. 1, the amount of deflection of the compression coil springs 10 and 11 will both be 1 mm, and the stress of the compression coil spring 10 will be:
The stress of the compression coil spring 11 decreases by 16g, and the stress of the compression coil spring 11 increases by 16g, resulting in a stress difference of 32g. The balance between this stress difference and the received pressure F is the received pressure F = 3.2
This is when the differential pressure P=10 mmAg from g/mmAg.
Therefore, the displacement of the diaphragm 5 and the pressure receiving plates 6, 7 with respect to the differential pressure P is 0.1 mm per 1 mm Ag of the differential pressure P.
becomes. Therefore, the slit plate 5 and the slit hole 17 are also displaced in the same way, and the optical image L is also deviated according to the displacement of the slit hole 17, so the optical image L has a differential pressure of P=1 mm.
The deviation is 0.2 mm per Ag. Therefore, the position of the optical image when the differential pressure P = 0 mmAg is shown in Figure 2.
When a DC voltage Vi=10V is applied between the electrodes 20 and 22 of the light receiving element 12 made of a photoconductive material, the output voltage Vo=5V as shown in FIG. 3, and the differential pressure P as shown in FIG. = OmmAg, the output voltage Vo = 5V. Next, when the differential pressure P changes, the deviation of the optical image is at a rate of 0.1 mm/mmAg, so when the differential pressure P = -20 mmAg and 20 mmAg, the deviation
are respectively X=-2mm and 2mm, and the output voltage Vo is 2V and 8V, respectively, so the differential pressure P
The relationship between the output voltage Vo and the output voltage Vo is a straight line as shown in FIG. 4, and exhibits extremely good characteristics even at low pressures.

Next, the effects of the pressure-electric conversion device of the present invention will be explained.

(1) It has good characteristics even against slight pressure, and whether the sign of the differential pressure is positive or negative, and whether it is more negative than positive or
Even if the pressure becomes more positive than negative, it can be continuously detected, there is no need to replace the high pressure inlet 3 and the low pressure inlet 4, and the electrical output signal is proportional to the differential pressure. In addition, the range of the detected pressure or the ratio of change in the electrical output signal to the pressure (proportionality constant) can be easily changed by simply changing the spring constant of one or both of the compression coil springs 10, 11. Can be used for a wide range of pressure detection and measurement.

(2) The light-receiving element 12 is composed of two photosensitive surfaces of the same shape made of the same photoelectric material on the same substrate, and is determined only by the ratio of areas A and B by the light image L, so the temperature and humidity characteristics , the aging characteristics are extremely excellent, and the light image L from the light source 13
It also has stable characteristics against changes in illuminance. Therefore, by appropriately selecting the shape and material of the diaphragm 5 and the compression coil springs 10 and 11, the ambient temperature, humidity, and life characteristics are extremely excellent. (In particular, if the light receiving element 12 is a hermetically sealed photoconductive cell and the light source 13 is a light emitting diode, the lifespan of these elements will be
Over 100,000 hours. ) (3) For example, when a photoconductive cell is used as the electrical output signal of the light receiving element 12, a sufficiently large DC output voltage Vo is obtained with respect to the applied voltage Vi, as shown in Fig. 3, and it is possible to detect pressure. Therefore, complicated circuits such as frequency modulation and phase modulation are completely unnecessary.

When the output impedance of the output signal is high, for example, 100KΩ or more, an emitter floor circuit using one transistor can be used to achieve high precision with a simple configuration without using expensive electronic components or circuits. Pressure detection or measurement becomes possible.

Furthermore, there are no expensive mechanical parts (diaphragms, compression coil springs, etc.), and the system as a whole can be realized at extremely low cost.

(4) Pressure-electric transducers that can detect small pressures are generally
Because it uses delicate parts, it is easily damaged.
As mentioned above, the pressure-electric transducer of the present invention has no parts that are easily damaged, has a structure that can withstand excessive pressure and impact, and is easy to assemble during manufacturing. That is, it is robust, easy to handle, and has excellent mass productivity.

FIG. 5 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate members having the same functions, and the description thereof will be omitted. 23 is a ring-shaped load plate attached to the pressure receiving plate 6. This load plate 23
is a replacement for the compression coil spring 10 in FIG. 1, and in FIG. 5 it is always on the lower side, that is,
When a constant stress is applied to the compression coil spring 11 in the direction of the acceleration of gravity, and the differential pressure P=OmmAg, the compression coil spring 11 is applied by an amount corresponding to the gravity applied by the load plate 23 compared to when there is no load plate 23. Causes deflection. Therefore, when the differential pressure P reaches a certain positive value, the spring 11 is deflected toward the low pressure side so that the differential pressure P becomes a stress equal to the receiving force F applied to the pressure receiving plate 6. When the differential pressure P reaches a certain negative value, the spring 11 is now deflected toward the high pressure side and is balanced.

In the end, the displacement is determined by the received force F and the spring constant k of the compression coil spring 11, and its characteristics are similar to those shown in FIGS. 3 and 4. Note that the pressure detection range can be easily changed by making the ring-shaped load plate 23 detachable and changing it to a load plate with a different weight.

FIG. 6 similarly shows another embodiment. Reference numeral 24 denotes a leaf spring formed into a substantially U-shape, and the opposing movable ends are connected to the upper and lower parts of the slit plate 9 by hinges, respectively, and the fixed end is connected to the low-pressure side case 2 with screws 25, 26.

When the differential pressure P=0 mmAg, the leaf spring 24 is holding the pressure receiving plates 6, 7 and the slit plate 9 in a substantially horizontal state, and at this time, the light from the light source 13 passing through the slit hole 17 is It is assumed that the optical image L formed on the photosensitive surface of the light receiving element 12 has a moving amount X=0 mm in FIG. Therefore, even if the differential pressure P becomes positive or negative, the leaf spring 24 generates stress depending on the amount of deflection, and since the amount of deflection is sufficiently small within the range of use,
The amount of deflection is proportional to the differential pressure P. The slit plate 9 is connected to the leaf spring 24 by a hinge, and since the slit plate 9 has a small amount of deflection, it is vertically displaced in an almost vertical state. Therefore, since the slit hole 17 is also displaced in accordance with the differential pressure P, the operation is the same as that of the embodiment shown in FIG.

The embodiments and other embodiments of the present invention have been described above, and techniques that can be selected as appropriate when implementing the present invention will be described below.

(1) In the embodiment and other embodiments, compression coil springs and leaf springs were used, but they may be selected as appropriate, such as by arranging a tension coil spring on the high-pressure side.

(2) Although the light-receiving element and the light source are placed on the low-voltage side, the same applies if they are placed on the high-voltage side.

(3) The diaphragm, especially when used under low pressure,
Characteristics such as temperature characteristics are improved when the groove part is as thin as possible (for example, 0.1 to 0.2 t if it is made of rubber), and the material should be appropriately selected depending on the fluid to be detected.

For example, if it is air, a silicon diaphragm would be most suitable. In addition to the diaphragm as shown in FIG. 1, a so-called velofram can also be used.

(4) The pressure displacement converter can also be constructed by using a metal verofram or the like and using both the action of a diaphragm and a spring.

(5) In addition to fixing the slit plate 9 by caulking it to the rivet 8, the slit plate 9 is attached to the rivet 8 using a hinge or a flexible ball, so that it can rotate freely left and right or left and right and front and back as shown in Fig. 1. , by not having any clearance in the vertical direction and preventing movement,
Even if the pressure-receiving plate is not completely horizontal but is displaced slightly tilted due to the pressure, the slit plate moves while maintaining its vertical direction, and the holder 14 or the light-receiving element 1
Since it is possible to prevent the sliding resistance from increasing due to contact with 2, the relationship between the pressure and the electrical output signal is stable with almost no change.

(6) In order to ensure that only the light that has passed through the slit hole 17 from the light source 13 is irradiated onto the light receiving element 12 and no other light is irradiated onto the light receiving element 12 (to improve the S/N ratio), As described above, in addition to making the distance between the slit plate 9 and the surface of the light receiving element 12 as small as possible, the inside of the high pressure side case 1, the low pressure measuring case 2, and especially the holding base 14 and the slit 9 are It is effective to make the surface matte black so that it absorbs and reflects light diffusely.

(7) The more the light image irradiated onto the light receiving element 12 always has the same shape and the illuminance is more uniform with respect to the displacement of the slit hole 17, the more linear the relationship between the pressure and the electrical output signal becomes, and the more the light receiving element 12 The effective stroke of the 12 detectable optical image deflections also increases. Therefore, (a) the distance between the slit plate 9 and the light receiving element 12 is made small, and the distance between the slit plate 9 and the light source 13 is made large.

(b) It is better for the light source 13 to be a point-emitting type, and a light emitting diode, especially a light emitting diode sealed with transparent glass or transparent resin, is considered to be optimal from the point of view of life characteristics.

(8) As mentioned above, the photoelectric material of the light receiving element 12 is
There are photoconductive cells such as CdS and CdSe, and silicon, and in addition to using changes in the resistance of photoelectric materials, it is also possible to use changes in superpower like selenium photocells.

(9) The shape of the photosensitive surface of the light receiving element 12 may be two simple triangles or a trapezoid.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a pressure-electric transducer according to an embodiment of the present invention, Fig. 2 is a diagram explaining the principle of the light-receiving element, Fig. 3 is a characteristic diagram of the light-receiving element, and Fig. 4 is a characteristic of the pressure-electric transducer. 5 and 6 are cross-sectional views showing other embodiments of the present invention. 5...Diaphragm, 6,7...Pressure plate, 9...
...Slit plate, 10,11...Compression coil spring,
12... Light receiving element, 13... Light source, 17... Slit hole, 18, 19... Photosensitive surface, 20, 21, 2
2... Electrode, L... Light image, 23... Load plate, 24
...Plate spring.

Claims (1)

[Scope of Claims] 1. A pressure displacement converter having a pressure receiving plate operated by a pressure difference between two fluids, a light source, and two photosensitive surfaces of the same shape made of photoelectric material. and a light-receiving element whose ratio of light-receiving areas differentially changes depending on the deviation of the optical image, and the pressure displacement converting section is continuously operated regardless of whether the sign of the differential pressure between the two fluid pressures is positive or negative. 1. A pressure-electric conversion device, characterized in that the pressure-electric conversion device is configured to be operated in a manner such that the deviation of an optical image on the photosensitive surface of the light-receiving element responds to the displacement given by the pressure-displacement conversion section. 2. The pressure-electric conversion device according to claim 1, wherein the pressure displacement converter includes a pressure receiving plate and two springs that bias the pressure receiving plate in opposing directions. 3. The pressure displacement converter includes a pressure receiving plate and a weight that applies a constant load in the direction of acceleration of gravity of the pressure receiving plate,
2. The pressure-electric transducer according to claim 1, further comprising a spring that applies stress in a direction opposite to the acceleration direction. 4. The pressure-electric conversion device according to claim 1, wherein the pressure displacement converter includes a pressure receiving plate and a leaf spring that applies stress to the pressure receiving plate even if the pressure receiving plate changes in any direction in which the pressure receiving plate faces. .