JPH0225725A - Differential pressure measuring instrument - Google Patents

Abstract

PURPOSE:To constitute a differential pressure measuring instrument body part and a changeover valve in one body and to make the title instrument small in size and light in weight, and to reduce its cost by providing two pieces of connecting holes on a base block, and executing the communication or cut-off of the connecting hole by sliding a communicating groove which is constituted in a piston. CONSTITUTION:Two pieces of connecting holes 43, 44 whose one end communicates with a pressure receiving chamber 41 and whose other end opens as a pressure receiving connecting port 45 are provided on a base block 4. The connecting holes 43, 44 usually communicate with each other, measured pressure is applied from the right and the left of a differential pressure sensor part 1, and its measuring diaphragm is displaced by differential pressure of the measured pressure. At the time of equalizing both measuring inputs of the instrument and adjusting a zero point of the instrument, first and the second communicating grooves 54, 55 constituted of a cylinder 51, a piston 52 and an O ring 53 are slid, each communication of the connecting holes 43, 44 is disconnected, the pressure receiving chamber 41 side of the connecting hole 43 and the pressure receiving chamber 41 side of the connecting hole 44 are allowed to communicate by the communicating groove 54, and also, the pressure receiving connecting port 45 side of the connecting hole 43 and the pressure connecting port 45 side of the connecting hole 44 are allowed to communicate by the communicating groove.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a differential pressure measuring device.

More specifically, the present invention relates to an input circuit of a differential pressure measuring device.

<Prior Art> FIG. 5 is a diagram illustrating the configuration of a conventional example of a flow rate measurement system using an orifice that has been commonly used.

In the figure, A is a conduit through which the measurement fluid flows.

B is an orifice provided in conduit A.

C is a conduit attached to pipe mA upstream or downstream of orifice B. C1 is a main valve that opens and closes the conduit.

D is a three-way valve connected to conduit C. Dl is a stop valve provided on the three-way valve, and D2 is a pressure equalization valve.

E is a differential pressure measuring device connected to a three-way valve.

<Problems to be Solved by the Invention> However, in such a device, the three-way valve and the differential pressure measuring device E are separate bodies, and mutual piping is required. Further, the device becomes complicated, and it is difficult to reduce the size and weight of the device and reduce the cost.

The present invention solves this problem.

The purpose of the present invention is to provide a differential pressure measuring device that is small and lightweight, eliminates the need for parts such as piping, reduces costs, is easy to switch input circuits, is inexpensive, and is capable of stable and accurate zero point adjustment. is to provide.

<Means for Solving the Problems> In order to achieve this object, the present invention includes a differential pressure sensor section provided with an overpressure protection mechanism, and a differential pressure sensor section each having one end connected to the differential pressure sensor section and guiding measurement pressure. A pressure receiving block, a pressure receiving block to which the other end of the pressure receiving pipe is fixed, a seal diaphragm provided on an outer surface of the pressure receiving block and forming a seal chamber communicating with the pressure receiving block and the pressure receiving block, and the pressure receiving block. a base block having a concave portion to which the seal diaphragm and a pressure receiving chamber are attached; and two connecting holes provided in the base block, one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port. , two communication grooves provided in the base block and provided on the peripheral surface of the piston body normally communicate each of the connection holes, and when adjusting the zero point, the communication grooves are slid in the axial direction of the piston. and then cut off the communication between the two connection holes, allowing communication between the pressure receiving chamber side of the one connection hole and the pressure receiving chamber side of the other connection hole, and connecting the pressure receiving chamber side of the one connection hole with the pressure receiving chamber side of the other connection hole, and connecting the pressure reception chamber side of the one connection hole with the pressure reception chamber side of the other connection hole. A differential pressure measuring device is constructed that includes a piston cylinder valve that communicates the pressure receiving connection port side of one connection hole with the pressure receiving connection port side of the other connection hole.

In the above configuration, normally the connection holes are connected to each other.
Since the measurement pressure is applied from the left and right sides of the main body, the measurement diaphragm is displaced by the difference in measurement pressure. The displacement of the measurement diaphragm differentially changes the capacitance between the fixed electrode and the measurement diaphragm, resulting in an electrical signal output corresponding to the differential pressure.

To equalize the remeasurement input of the device and adjust the zero point of the device, slide the two communication grooves provided on the circumference of the piston to cut off communication between the two connection holes. , One communication groove connects the pressure receiving chamber side of one connection hole and the pressure receiving chamber side of the other connection hole, and the other communication groove connects the pressure receiving connection port side of one connection hole and the other connection hole. After communicating with the mouth side, the zero point of the device is adjusted.Hereinafter, a detailed explanation will be given based on an example.

<Example> FIG. 1 is an explanatory diagram of the main part of an embodiment of the present invention.

In the figure, 1 is a differential pressure sensor section.

As shown in FIG. 2, 11 is a block-shaped main body made of metal.

12 is an internal chamber provided in the main body 11.

Reference numeral 13 denotes a measuring diaphragm which divides the internal chamber 12 into two measuring chambers 14 and 15 and functions as a moving electrode.

Insulating films 131 and 132 are provided on the wall surface of the internal chamber 12 and are made of a plasma sprayed ceramic film. In this case, the thickness is 0.2 to 0.5 mm.

133, 134 are fixed electrodes provided on the surface of the insulation M 131, 132, respectively, on the wall of the internal chamber 12, facing the measuring diaphragm 13.

Reference numeral 2 denotes a pressure guiding pipe which is connected at one end to the differential pressure sensor section 1 and guides the measured pressure.

Reference numeral 3 designates pressure receiving blocks to which the other ends of the pressure guiding pipes 2 are respectively fixed.

A seal diaphragm 31 is provided on the outer surface of the pressure receiving block 3 and constitutes a seal chamber 32 that communicates with the pressure receiving block 3 and the pressure guiding pipe 2.

4 is a seal diaphragm 3 to which a pressure receiving block 3 is attached.
1 and four parts 42 forming a pressure receiving chamber 41.

Reference numerals 43 and 44 denote two connection holes provided in the base block 4, one end communicating with the pressure receiving chamber 41 and the other end opening to the outside as a pressure receiving connection port.

In this case, the connection hole 43 is connected to the high pressure side of the fluid to be measured, and the connection hole 44 is connected to the low pressure side.

Reference numeral 5 denotes a piston-cylinder valve, as shown in FIG.
It consists of an O-ring 53 provided on the circumferential surface of.

However, the cylinder 51. Piston 52 and O-ring 5
3 and 1. Second communication grooves 54 and 55 are configured.

The first communication well 54 normally communicates with the connection hole 43, and the second communication groove 55 normally communicates with the connection hole 44.

When adjusting the zero point, the first. The second communication grooves 54 and 55 slide in the axial direction of the piston 52 and cut off the communication between the two connection holes 43 and 44, and the first communication groove 54 opens the pressure receiving chamber 41111 of the connection hole 43! ! I and the pressure receiving chamber 4 of the connection hole 44
1 (Fl), and the second communication groove 55 connects the connecting hole 4.
The pressure receiving connection port 45 side of No. 3 and the pressure receiving connection port 451 of the connection hole 44
1! This is a piston-cylinder valve that communicates with l.

6 is a cover attached to the base block 4, covering the differential pressure sensor section 1, as shown in FIG.

Reference numeral 61 denotes a glint plate unit attached to the cover 6 and having electronic components attached thereto.

Reference numerals 101 and 102 indicate a liquid sealed in two chambers consisting of a measurement chamber 14 and 15, a pressure impulse tube 2, and a seal chamber 32. In this case, silicone oil is used.

In the above configuration, since the connecting holes 43 and 44 are normally in communication with each other, measurement pressure is applied from the left and right sides of the main body 11, and the measurement diaphragm 13 is displaced by the difference in the measurement pressures. By displacement of the measuring diaphragm 13, the capacitance between the fixed type [x133° 134 and the measuring diaphragm 13 changes differentially, and an electrical signal output corresponding to the differential pressure is obtained.

In order to equalize the constant inputs on both sides of the device and adjust the zero point of the device, as shown in Fig. 4, step 1. 2nd Rentsu Qing 54.5
5 slides in the axial direction of the piston 52 and has two connecting holes 43.
．． 44, the first communication groove 54 communicates the pressure receiving chamber 41fflI of the connection hole 43 with the pressure receiving chamber 41 (1!I of the connection hole 44), and the second communication groove 55 connects the pressure receiving chamber 41fflI of the connection hole The zero point of the device is adjusted after communicating the pressure receiving connection port 451111 and the pressure receiving connection port 45 side of the connection hole 44. As a result, (1) The main body of the differential pressure measuring device and the switching valve were integrated; Bolts, body flanges, mounting brackets, etc. are not required, making it compact, lightweight, and cost-effective.

(2) Piping between the main body of the differential pressure measuring device and the switching valve becomes unnecessary.

(3) Since the differential pressure sensor unit 1 is separated from the base block 4 by the impulse pipe 2 and supported in the air, it is not affected by the temperature of the measured fluid even if the measured fluid is high temperature.
<, a device with a wide measurable temperature range can be obtained.

(4) Switching of input circuits can be done by simply sliding the piston 52.

(5) Since the piston cylinder valve 5 is composed of a hole in a cylindrical cylinder 51, a cylindrical piston 51, and an O-ring 53, it can be manufactured at low cost.

(6) When adjusting the zero point of the device, the first communication groove 54 communicates the pressure receiving chamber 41 (Il of the connection hole 43 with the pressure receiving chamber 41 side of the connection hole 44), and the second communication groove 55 connects the connection hole 4
3 pressure receiving connection port 451Fl and connection hole 44 pressure receiving connection port 4
Since the zero point of the device is adjusted after communicating with the 5 side, the zero point can be adjusted easily and accurately without being affected by fluctuations in the measured pressure.

(7) Since the insulating films 1.31 and 132 are made of sprayed ceramics, they can be made extremely thin, but there is no need to hold the main body 11 large, and the strength of the main body 11 can be increased. 11 can be made smaller, and the entire device can be made smaller.

In the above-described embodiments, the piston-cylinder valve was described as being manually operated, but it goes without saying that a remote-type valve using a solenoid valve or the like may also be used.

<Effects of the Invention> As explained above, the present invention comprises: a differential pressure sensor section equipped with an overpressure protection mechanism; a pressure impulse tube whose one end is connected to the differential pressure sensor section and which guides measured pressure; a pressure receiving block to which the other ends of the pressure pipes are each fixed; a seal diaphragm provided on the outer surface of the pressure receiving block and forming a seal chamber communicating with the pressure receiving block and the pressure impulse pipe; and a seal diaphragm to which the pressure receiving block is attached. a base block having a concave portion constituting a pressure receiving chamber; two connection holes provided in the base block, one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port; Normally, each of the connecting holes is connected by each of the two communicating grooves provided on the circumferential surface of the piston body, and when adjusting the zero point, the two communicating grooves are slid in the axial direction of the piston. The communication of each of the connection holes is cut, one communication groove connects the pressure receiving chamber side of the one connection hole and the pressure reception chamber side of the other connection hole, and the other communication groove connects the pressure reception chamber side of the one connection hole. A differential pressure measuring device is constituted by comprising a stone cylinder valve that communicates the pressure receiving connection port side with the pressure receiving connection port side of the other connection hole.

As a result, (1) Since the main body of the differential pressure measuring device and the switching valve can be integrated, there is no need for bolts, main body flanges, mounting brackets, etc., resulting in smaller size, lighter weight, and cost reduction.

(2) Piping between the main body of the differential pressure measuring device and the switching valve becomes unnecessary.

(3) The differential pressure sensor part is separated from the base block by an equal pressure tube and supported in the air, so even if the fluid to be measured is at high temperature, it is not affected by the temperature of the fluid to be measured and is within the measurable temperature range. A wide device is obtained.

(4) Switching of input circuits can be done with one touch, since all you have to do is slide the piston.

(5) The piston-cylinder valve is composed of a cylindrical cylinder hole, a cylindrical piston, and an O-ring, so it can be manufactured at low cost.

(6) When adjusting the zero point of the device, slide the two communication grooves to cut off communication between the two connection holes, and use one communication groove to connect the pressure receiving chamber side of one connection hole to the pressure receiving chamber side of the other connection hole. The zero point of the device is adjusted after communicating the pressure receiving chamber side of the connection hole and communicating the pressure receiving connection port side of one connection hole and the pressure receiving connection port side of the other connection hole through the other communication groove. The zero point can be adjusted easily and accurately without being affected by fluctuations in measurement pressure.

Therefore, according to the present invention, the differential pressure measuring device can reduce costs by being smaller and lighter, eliminates the need for parts such as piping, is easy to switch input circuits, is inexpensive, and can stably and accurately adjust the zero point. can be realized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, FIG.
FIGS. 3 and 4 are explanatory views of the main part configuration of FIG. 1, and FIG. 5 is an explanatory view of the configuration of a conventional example that has been generally used. 1... Differential pressure sensor section, 101, 102. ... Filled liquid, 11 ... Main body, 12 ... Internal chamber, 13 ... Measurement diaphragm, 131.132 ... Insulating film, 133.
134...Fixed electrode, 14.15...Measurement chamber, 2.
... Impulse pipe, 3... Pressure receiving block, 31... Seal diaphragm, 32... Seal chamber, 4... Base block, 41... Pressure receiving chamber, 42... Recess, 43.4
4... Connection hole, 45... Pressure receiving connection port, 5... Piston cylinder valve, 51... Cylinder 52...
Piston, 53...0 ring, 54...first communication groove, 55...second communication groove, 6...cover, 61...printed board unit. Figure 11 Two bodies Figure 54 Communication 4 Funeral i Figure

Claims (1)

[Claims] A differential pressure sensor section equipped with an overpressure protection mechanism, a pressure impulse tube whose one end is connected to the differential pressure sensor section and which guides the measured pressure, a pressure receiving block to which the other end of the impulse tube is fixed, and the pressure receiving block. a seal diaphragm provided on the outer surface of the block and forming a seal chamber communicating with the pressure receiving block and the pressure impulse pipe; a base block having a recess to which the pressure receiving block is attached and forming a pressure receiving chamber with the seal diaphragm; Two connection holes provided in the block, one end communicating with the pressure receiving chamber and the other end opening to the outside as a pressure receiving connection port, and two communication grooves provided in the base block and provided in the circumferential surface of the piston body. Normally, each of the two connecting holes is communicated with each other, and when the zero point is adjusted, the communicating groove is slid in the axial direction of the piston to disconnect each of the two connecting holes, and one of the two connecting holes is used to disconnect the two connecting holes. The pressure receiving chamber side of the connecting hole and the pressure receiving chamber side of the other connecting hole are connected through the other communication groove, and the pressure receiving connecting port side of the one connecting hole and the pressure receiving connecting port of the other connecting hole are connected. A differential pressure measuring device comprising a piston cylinder valve communicating with the side.