JPS5917126A - Differential pressure transmitter - Google Patents

Abstract

PURPOSE:To measure a micro differential pressure with good accuracy by providing plural pieces of pressure deforming bodies having different measurement ranges, and converting the detection signals obtd. from the pressure deforming bodies to electrical signals corresponding to the pressure difference. CONSTITUTION:When the pressures PH, PL of fluids to be measured are applied on the surfaces 36, 37 of sealing diaphragms 30, 31, these pressures are transmitted through silicone oil 26 to the measuring chambers 141-144 disposed on both sides of measuring diaphragms 131-134 and an internal chamber 21. If there is a difference in the pressures between the chambers 141-144 and the chamber 21, the diaphragms 131-134 deform. Strain gages 401-404 generate detection signals according to the deformation and further a signal processing circuit 50 converts the same to the electric signal corresponding to the pressure difference and transmits the signal to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a differential pressure transmission device.More specifically, the present invention relates to a differential pressure transmission device.More specifically, the present invention relates to a differential pressure transmission device. The present invention relates to a differential pressure transmission device that converts and transmits the data.

Conventionally, this type of differential pressure transmission device detects the difference between two pressures using one pressure deformable body that deforms according to the pressure difference, and the differential pressure detection means generates a detection signal by this deformation. There was one that converted the pressure difference into an electrical signal and transmitted it to the outside.

However, in such a differential pressure transmission device, the pressure deformable body is 1
Since only one is provided, there is a problem that a large differential pressure cannot be measured when the measurement range of the pressure deformable body is small. Further, when the measurement range of the pressure deformable body is wide, there is a problem in that minute pressure differences cannot be measured with high precision. If the pressure deformable body installed in the differential pressure transmission device is replaced with one of a different measurement range depending on the differential pressure to be measured, pressure deformable bodies for many measurement ranges can be prepared as spare parts in case of failure. There was a problem that it had to be kept.

A plurality of pressure displacement bodies with different measurement ranges are provided, and a detection signal obtained from one of the pressure displacement bodies is selectively converted into an electric signal according to the pressure difference according to the pressure difference to be measured, and the signal is transmitted externally. By transmitting the data, the above-mentioned problems can be solved. However, with this method, each pressure deformation body has a different strength against overrange (overrange pressure resistance), so when measuring a large differential pressure, the pressure deformation body with a small overrange pressure resistance will overrange and be destroyed first. There was a problem that

The present invention has been made to eliminate the above-mentioned problems, and is capable of measuring minute differential pressures with high precision and measuring large differential pressures, has a wide measurable range, and is capable of making necessary corrections. The object of the present invention is to provide a differential pressure transmission device that requires fewer parts and that prevents destruction of a pressure deformable body due to possible overrange.

FIG. 1 is a diagram showing the configuration of an embodiment of a differential pressure transmission device according to the present invention. 2 is a diagram showing the configuration of the sensor section in FIG. 1, in which (a) is a longitudinal sectional view and (b) is a view seen from the direction of arrow A in (a).

In these figures, 10 is a sensor section, 20 is a body,
30 and 31 are seal diaphragms, 40 is a differential pressure detection means, and 50 is a signal processing circuit.

In the sensor section 10, reference numeral 11 is a substrate for a pressure deformable body, such as a diaphragm substrate, and is made of an elastic material. Reference numeral 12 denotes a pressure deformable body support member, such as a diaphragm support member, to which the diaphragm substrate 11 is bonded, for example, by electrostatic bonding. In addition, the diaphragm substrate 1
1 is a diaphragm support member 1 with adhesive etc.
It may be joined to 2. The diaphragm substrate 11 constitutes a pressure deformable body, for example a measuring diaphragm 13, in its thin portion.

Four measurement diaphragms 13 are provided from 13□ to 134. The measurement range of each measurement diaphragm is, for example, the measurement diaphragm 131 is 0.01-0.1kg/a.
m.

The measuring diaphragm 132 is 0.1-1 kg/cm2, the measuring diaphragm 133 is 1-10 kg/cm2, and the measuring diaphragm 13 is 10-100 kg/cm2. Note that the measurement range of each measurement diaphragm may be a value other than this. Each measurement diaphragm 13□~13
The overrange pressure resistance of No. 4 corresponds to the size of the measurement range, and is weaker in the order of 131.13°, 133°, and 134°.

Each measurement diaphragm 13□-134 has a measurement chamber 14□-144 between it and the diaphragm support member 12. It consists of Each measurement chamber 14□ to 144 is separated from each other. 151 to 154 are pipe lines, one end of which is the measurement chamber 14□~
144. The conduits 151 to 154 fix the sensor section 10 to the body 20 via the fixing base 16. The sensor section 10 is arranged in an internal chamber 21 provided in the body 20. The sealing diaphragm 30.31 forms a compartment 34.35 with one side 32.33 and the body 20. A fluid passage 22 connecting the compartment 34 and the pipe line 15 is formed in the body 20 . The fluid passage is 22□
There are four lines from 224 to 224. first fluid passage 2
2□ connects the compartment 34 and the conduit 154. The second fluid passage 22□ connects the first fluid passage 221 and the conduit 153. Third fluid passage 223 connects second fluid passage 222 and conduit 152 . The fourth fluid passage 224 connects the fifth fluid passage 223 and the conduit 151. (The fifth fluid passage 223 and the fourth fluid passage 2
24 connections are shown in FIG. ) fourth fluid passageway 224;
Valves 23□, 232 and 233 are attached to the third fluid passage 223 and the second fluid passage 22°, respectively. The valve 23 has a flow path 24, for example, as shown in FIG. By rotating the flow path 24 in the BB' direction, it can be switched between an open state as shown in FIG. 3(a) and a closed state as shown in FIG. 3(b). Note that the valve 23 may have a configuration other than this. The compartment 35 is a conduit 2 provided in the body 20.
5 communicates with the internal chamber 21. The pressure PH+PL of the fluid to be measured is applied to the other surfaces 36, 37 of the seal diaphragm 30.31. Measurement room 14□
~144, pipe lines 15□~154, internal chamber 21, fluid passages 221-224, flow path 24, pipe line 25, and compartment 34.
35 is filled with an incompressible pressure transmitting fluid such as silicone oil 26. The differential pressure detection means 40 are, for example, diffusion type strain gauges, and are provided in the same number as the measurement diaphragms 13 from 401 to 404. The strain gauges 40 to 404 are attached to one measurement diaphragm 131 to 134, respectively. Strain gauges 40 to 404 are measurement chamber 1
The measurement chambers 141 to 144 are deformed due to the pressure difference between the measurement diaphragms 131 to 134 and the internal chamber 21.
A detection signal corresponding to the pressure difference f between the internal chamber 21 and the internal chamber 21 is generated.

The signal processing circuit 50 converts the detection signals from the strain gauges 401 to 404 into electrical signals according to the pressure difference between the measurement chamber 14 and the internal chamber 21 and transmits the signal to the outside, and also converts the detection signals from the strain gauges 401 to 404 into electrical signals corresponding to the pressure difference between the measurement chamber 14 and the internal chamber 21 and transmits the signal to the outside. The valve corresponding to the overranged measuring diaphragm is selectively closed to prevent the measuring diaphragm from being destroyed.

In the differential pressure transmission device having such a configuration, the pressure P of the fluid to be measured is applied to the surface 36.37 of the seal diaphragm 30.31.
When the HT PL is applied, these pressures are transferred to the measuring chambers 141 to 144 and the internal chamber 21 arranged on both sides of the measuring diaphragms 131 to 134 via the liquid pressure oil 26.
can be conveyed to. If there is a difference in pressure between the measurement chambers 141 to 144 and the internal chamber 21, the measurement diaphragms 13 to 134
transforms. Due to this transformation, Strainage 401~
404 generates a detection signal, and further, the signal processing circuit 50 converts it into an electric signal according to the pressure difference and transmits it to the outside. The signal processing circuit 50 will be explained using FIG.

FIG. 4 is a block diagram of an electric circuit used in the differential pressure transmission device of FIG. 1. In FIG. 4, the same parts as in FIG. 1 are given the same reference numerals.

In FIG. 4, 60 is a signal transmission means, and 70 is a controller. The signal transmission means 60 and the controller 70 constitute a signal processing circuit 50.

In the signal transmission means 60, 61 is a converter, which converts the detection signals from the strain gauges 40□ to 404 into electric signals e□ to e4 according to the differential pressure. An amplifier 62 converts the electrical signal from the converter 61 into a predetermined unified signal, such as 1-5V DC, 4-20m, iDC, etc., and transmits it to the outside as an output signal. The amplifier 62 is provided with span adjustment means (not shown). 63 is a changeover switch, which switches between the converter 61 and the amplifier 6 according to the differential pressure to be measured.
By switching the connection state with 2, one of the electrical signals e-e4 of the converter 61 is sent to the amplifier 62. Electric signals 01 to e4 corresponding to the differential pressures of the strain gauges 401 to 404 are sent from the converter 61 to the controller 70 .

From the electrical signals 01-e4, the controller 70 closes the valve corresponding to the ranged measuring diaphragm to prevent destruction of the measuring diaphragm.

In such an electric circuit, by selectively switching the connection state of the changeover switch 63 to the measurement diaphragm of the measurement range closest to the differential pressure to be measured, the differential pressure detected by the υ measurement diaphragm; unified according to the differential pressure. It is converted into a signal and transmitted to the outside.

By switching the changeover switch 63 like this, the
A pressure difference of 0 kg/Cm can be measured.

Furthermore, prevention of damage to the measuring diaphragm due to autowaving is carried out as follows.

The measuring range of the measuring diaphragm 13 is 131.13°.

133 and 134, so when a differential pressure is applied, the measuring diaphragm 13 ranges in this order.

In addition, the over range pressure of the measuring diaphragm 13 is also smaller in the order of 13□, 13°, 133, and 134. Therefore, when measuring the differential pressure, the differential pressure to be measured is the over range of the measuring diaphragm 131. Then, the controller 70 closes the valve 231 by the electrical signal e1 corresponding to the differential pressure sent from the converter 61. As a result, the first fluid passage 22□ is closed, and no further flow is applied to the measuring diaphragm 13□. The differential pressure is no longer applied and destruction is prevented. In the same manner, when the differential pressure reaches the range pressure of the measuring diaphragms 132 and 133, the controller 70 closes the valves 232 and 233.
This prevents the measurement diaphragms 132 and 133 from being destroyed. The measurement diaphragm 134 is not provided with a valve to prevent damage due to overrange, and is used as a measurement diaphragm for monitoring overrange of the entire device. Therefore, the device can be used within a differential pressure range below the overrange pressure of the measuring diaphragm 134.

Note that a valve for preventing overrange damage may be provided for the measurement diaphragm 134.

According to the differential pressure transmission device having such a configuration, since a plurality of i measurement diaphragms 13 with different measurement ranges are provided, minute differential pressures are detected by the measurement diaphragm 131 with a small measurement range, Large differential pressures can be detected with a measuring diaphragm, such as 134, which has a narrow measuring range.

Therefore, the measurable range is wide because it is possible to measure a large differential pressure while measuring a small differential pressure with high accuracy.

Furthermore, since the measurement range can be changed by switching the changeover switch 52, there is no need to prepare a measurement diaphragm for a different measurement range as a spare part in order to change the measurement range.

This reduces the number of spare parts needed. The controller 70 receives electric signals e-4 from the converter 61 and closes the valve corresponding to the overranged pressure deformable body, so that it is possible to prevent the pressure deformable body from being destroyed by the overrange. can.

In the embodiment, the case where the pressure deformable body 13 is a diaphragm has been described, but the pressure deformable body 13 may be other than this, such as a bellows.

Further, in the embodiment, the case where four measuring diaphragms 13 are provided has been described, but the measuring diaphragms 13
may be provided in other numbers.

In addition, in the embodiment, the case where the differential pressure detection means 40 is a strain gauge has been described, but 1. The differential pressure detecting means 40 may be other than this, for example, an electrode attached to the measuring diaphragm 13 and an internal chamber 2 opposite to this electrode.
It may also be of a capacitive type, consisting of an electrode attached to 1.

Further, in the embodiment, the case where the pressure transmitting fluid 26 is silicone oil has been described, but the pressure transmitting fluid 26 may be other than this.

Further, in the embodiment, a case has been described in which the strain gauge 40 is attached to the measuring diaphragm 13. However, the present invention is not limited to this, and the measuring diaphragm 13 itself is deformed and generates a detection signal according to the differential pressure. It may also be a semiconductor strain gauge made up of.

Further, in the embodiment, a case has been described in which the signal transmission means 60 for converting the detection signal from the strain gauge 40 into a unified signal according to the differential pressure is attached to the outside of the body 20, but the signal transmission means is not limited to this. 60 may be attached to the measurement diaphragm 13 or the like. With current technology, it is possible to consolidate sensor parts, and the diameter is 10 to 2.
It is possible to manufacture a 5 mm disk-shaped diaphragm substrate provided with 4 to 6 measurement diaphragms and the signal transmission means 60.

In addition, in the embodiment, the measurement diaphragm 13 of the sensor section 10
Although the case has been described in which the measurement diaphragm 13 is attached to the body 20 via the fixing base 16, the measurement diaphragm 13 is not limited to this and may be attached directly to the body 20.

In the embodiment, a case has been described in which a plurality of measurement diaphragms 13 with different measurement ranges are arranged in parallel, but the invention is not limited to this, and as shown in FIG. 5, a plurality of measurement diaphragms 13 with different measurement ranges can be arranged in series. may be placed. Thereby, the space in the width direction of the sensor section 100 can be saved.

As explained above, according to the present invention, it is possible to measure small differential pressures with high precision and large differential pressures, the measurable range is wide, fewer spare parts are required, and there is no risk of overrange. It is possible to provide a differential pressure transmission device in which destruction of the pressure deformable body is prevented.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the configuration of an embodiment of the differential pressure transmission device according to the present invention, and FIG. 2 is a diagram showing the configuration of the sensor section in FIG. (a) is a longitudinal sectional view, (b) is a view seen from the direction of the arrow in (a), Fig. 5 is a diagram showing an example of the configuration of the valve in Fig. 1, and (a) is an open view. FIG. 4 is a block diagram of an electric circuit used in the differential pressure transmission device of FIG. 1. FIG. 5 is a diagram showing another arrangement of pressure deformable bodies used in the differential pressure transmission device of FIG. 1. 13, 13□~134...pressure deformable body, 22.22□
~224...Fluid passage, 23.23□~233...
Valve, 60... Signal transmission means, 70... Controller. Figure 3 Figure 4

Claims (1)

[Claims] A differential pressure transmission device that detects the difference between two pressures with a pressure deformable body that deforms according to the pressure difference, converts it into an electrical signal according to the pressure difference, and transmits it. Different pressure deformable bodies, a valve attached to a fluid passage that applies the pressure of the fluid to be measured to each pressure deformable body, and a detection signal obtained from the pressure deformable body selectively applied to the pressure according to the pressure difference to be measured. a signal transmission means for converting and transmitting an electrical signal according to the difference; and a pressure deformable body that selectively closes a valve corresponding to the pressure deformable body when the pressure deformable body is overranged due to the pressure of the fluid to be measured. A differential pressure transmission device characterized by comprising a controller that prevents destruction of the.