JPH06194245A - Differential pressure detector with diaphragm unit - Google Patents

Abstract

PURPOSE:To provide a differential pressure detector where the inside of a connecting pipe for a diaphragm unit can be degassed completely and quickly and an incompressive fluid can be also sealed as well so that the fluids on the respective measuring pressure sides may be stably detected for differential pressure in a high temperature and vacuum state. CONSTITUTION:An intermediate body 7 having a hollow part for communicating with a connecting pipe 6 is prepared at the central part of the pipe 6, and the body 7 is provided with a hole 7a for communicating with the hollow part. Since the degassing and sealing of a silicone oil are performed through a hole 2a of a differential pressure detecting part 1, a hole 5a of a flange 5 and the hole 7a, even when the inside diameter of the pipe is about 2mm and the length thereof is around 1.5-6m, there would remain almost no gas in the silicone oil inside the pipe. In addition, the number of the intermediate bodies 7 may be increased according to the length of the pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can completely and quickly deaerate the inside of a connecting pipe of a diaphragm unit and enclose a non-compressible fluid. The present invention also relates to a differential pressure detection device with a diaphragm unit capable of stable differential pressure detection. If one of the measured pressures is atmospheric pressure or vacuum, the gauge pressure or absolute pressure detection device is obtained.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional example.
Will be described with reference to. In the figure, the differential pressure detector 1
Is based on, for example, a capacitance method, and the pressure receiving portion side of each pressure is covered by the cover 2. The flange 5 is
It has a sealing diaphragm 4 that receives the measurement pressure and is connected to the cover 2 by a pipe 6. The flange 5 including the seal diaphragm 4 and the pipe 6 constitute a diaphragm unit. Silicone oil as a pressure transmitting fluid is sealed in the inner space of the diaphragm unit and the inner space of the cover 2. The silicone oil is sealed in the hole 2a of the cover 2 and the hole 5a of the flange 5.
It is done through and. In addition, the hole 5a of the flange 5
Is opened so that the central hole of the flange 5 and the atmosphere communicate with each other, as shown in the figure. Each hole 2a, 5a is sealed after enclosing.

The structure of the differential pressure detector 1 is the same as that of the embodiment and is shown in the sectional view of FIG. In FIG.
The differential pressure detection unit is roughly divided into a detection unit 20 and a protection unit 30, which are connected via pressure guiding pipes 16 and 17. Detection unit
Reference numeral 20 converts the differential pressure to be measured into an electric signal and outputs the electric signal. The protective portion 30 will be described later in detail.
Protect 20. Since the configuration of the detection unit 20 is well known, its description is omitted. In addition, the detection unit 20 is a protection unit.
Although there is another conventional device that is configured to be installed internally in 30, the purpose of the configuration in which the detection unit 20 is externally installed in the protection unit 30 is that the influence of the temperature on the detection unit 20 when the measurement fluid has a high temperature. This is to prevent it from reaching.

Now, the protection unit 30 is mainly composed of the main bodies 31, 32,
Protective diaphragm 13 and seal diaphragms 34,35
Consists of. Here, the members having the same names of the main bodies 31 and 32 and the seal diaphragms 34 and 35 are the same. Main bodies 31 and 32 are respectively arranged on the left and right sides with the protective diaphragm 13 interposed therebetween, and are joined to each other at their outer circumferences or peripheral portions.

Further, the same concave portion is formed in each of the main bodies 31 and 32.
15, 25, holes 14, 24 and holes 45, 55 are formed. More specifically, the main body 31 on the right side is described as follows. The recess 15 is formed on the left side surface of the main body 31 in the shape of a mortar that is coaxial therewith, the hole 14 penetrates the main body 31 along its axis, and the hole 45 opens on the one hand in the vicinity of the center of the recess 15 of the hole 14, and on the other hand Then, it penetrates the pressure guiding pipe 16 and communicates with a pressure guiding space (not shown) of the detection unit 20. The right side surface of the main body 31 is formed in a corrugated cross section, and the seal diaphragm 34 having the same shape as the corrugated shape is formed.
Is fixed to the right side surface of the main body 31 at its peripheral edge with a space. A cover (not shown) is attached to the right side of the main body 31 at the outer peripheral edge of the seal diaphragm 34, though not shown.

The above is substantially the same for the main body 32 on the left side. And the sealing diaphragms 34, 35
Silicon oil (filled liquid) as a fluid for pressure transmission is filled in each of the space in contact with, the holes 14, 24, the recesses 15, 25, and the holes 45, 55. Differential pressure detector 1
Even if the fluid whose pressure is to be measured has a high temperature and a high degree of vacuum, by providing a diaphragm unit for each measured pressure, the influence is not exerted on the differential pressure detection unit 1, and an accurate differential pressure is detected. Allows measurement of pressure.

By the way, as a matter of course, the silicone oil sealed in the inner space of the diaphragm unit and the inner space of the cover 2 needs to be sufficiently deaerated. Otherwise, if the fluid whose pressure is to be measured has a high temperature and a high degree of vacuum, the gas in the silicone oil is affected by the high temperature and the gas in the silicone oil is initially small, and the gas expands to increase the pressure. This is because transmission to the differential pressure detection unit 1 becomes impossible. The degassing of the encapsulated silicone oil is performed by the hole 2a of the cover 2 and the flange 5
Through the hole 5a of the. That is, each hole 2
a and 5a are commonly used for deaeration and encapsulation of silicone oil. After the liquid is filled, the opening of the hole 5a of the flange 5 is sealed with a ball pressed by a set screw.

[0008]

In the conventional example, when the fluid on each measurement pressure side becomes high temperature and high vacuum, the output of the device gradually changes in one direction, so-called drift occurs. It may cause a failure that the player shakes off. The cause is that a slight amount of gas remaining in the silicone oil sealed inside the connecting pipe 6 expands due to the high temperature and high vacuum of the fluid on each measurement pressure side, which causes the measurement pressure detection section to reach the detection section. This is because it impedes accurate transmission. Moreover, the pipe 6 has an inner diameter of 2 mm and a length of 1.5 to 6 m.
Since it is only a degree, it is in an unfavorable condition for complete degassing and filling. In any case, it is important to minimize the amount of gas remaining in the encapsulated silicone oil.

The object of the present invention is to solve the above problems of the prior art, and to completely and quickly perform deaeration and encapsulation of an incompressible fluid inside the connecting pipe of the diaphragm unit.
An object of the present invention is to provide a differential pressure detection device with a diaphragm unit that can perform stable differential pressure detection even when the fluid on each measurement pressure side is in a high temperature and high vacuum state.

[0010]

According to another aspect of the present invention, there is provided a differential pressure detecting device with a diaphragm unit, wherein each pressure relating to the differential pressure to be measured is inside a diaphragm unit having a pressure receiving seal diaphragm flange and a connecting pipe. In a device which is transmitted to a differential pressure detection unit via an incompressible fluid to be sealed, it is sealed at one or more intermediate points of the pipe after degassing of the pipe and enclosing the incompressible fluid inside. An opening is provided.

According to a second aspect of the present invention, there is provided a differential pressure detecting device with a diaphragm unit according to the first aspect, wherein the opening is provided at one or more intermediate positions of the pipe to prevent degassing inside the pipe. It is the hollow part of the tubular body that is sealed and cut off after enclosing the compressive fluid. A differential pressure detecting device with a diaphragm unit according to a third aspect of the present invention is the device according to the second aspect, in which the sealing cutting of the tubular body includes a pressure contact cutting step and a subsequent sealing welding step.

[0012]

In the differential pressure detecting device with a diaphragm unit according to any one of claims 1 to 3, an opening is provided at one or more intermediate positions of the pipe, and the degassing inside the pipe is performed through the opening. And then sealed with a non-compressible fluid encapsulation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a differential pressure detecting device with a diaphragm unit according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the embodiment. This embodiment is different from the conventional example in that an intermediate body 7 having a hollow portion communicating with the pipe 6 is provided at an intermediate portion of the connecting pipe 6, and the intermediate body 7 has a hole 7a communicating with the hollow portion. Is opened. Since the deaeration and the encapsulation of silicone oil are performed through the hole 7a together with the hole 2a of the differential pressure detecting portion 1 and the hole 5a of the flange 5, the inner diameter of the pipe 6 is as small as about 2 mm and the length is 1.5 ~. Even if the length is about 6 m, almost no gas can remain in the silicone oil inside. The number of intermediates 7 may be increased as the pipe 6 becomes longer.

By the way, when degassing and encapsulation of silicone oil are performed through the hole 7a of the intermediate body 7, the hole 7a
It is carried out through another pipe connected to a and sealed when finished. FIG. 2 is a side view showing the sealing cut of the pipe in the embodiment. In FIG. 2, the hole 7a
The pipe 10 is welded to the intermediate body 7 at a location so as to communicate with, and is connected to a liquid sealing device (not shown) through a connecting fitting 11 indicated by a chain double-dashed line attached to the upper end portion thereof. After the silicone oil has been filled, the pipe 10 is cut off at the location. This sealing cut consists of so-called pressure welding, which is cut at the same time as the pressure welding, and then sealing welding. This double method improves the sealing reliability.

[0015]

In the differential pressure detecting device with a diaphragm unit according to any one of claims 1 to 3, an opening is provided at one or more intermediate portions of the pipe, and the inside of the pipe is opened through this opening. Sealed after degassing and incompressible fluid encapsulation. Therefore, degassing and filling of the incompressible fluid inside the connecting pipe of the diaphragm unit are completely and quickly performed, and almost no residual air remains in the filled fluid, so that the fluid on each measurement pressure side has high temperature and high vacuum. Even in this state, the residual air does not expand and hinders accurate pressure transmission, and stable differential pressure detection can be performed.

Particularly, in the differential pressure detecting device with a diaphragm unit according to a second aspect, the pipe body is provided at one or more intermediate positions of the pipe, and the inside of the pipe is deaerated and the incompressible fluid is enclosed through the hollow portion. After that, the hollow portion is sealed and cut. Therefore, there is no risk of entrapment of air during sealing, and stable differential pressure detection in the high temperature and high vacuum state of each measured pressure side fluid is supported.

Particularly, in the differential pressure detecting device with a diaphragm unit according to a third aspect, since the tubular body is sealed and cut by the pressure contact cutting and the subsequent hermetic welding, there is no risk of entraining air during the sealing. In addition, the reliability of sealing is improved, and the stable differential pressure detection in the high temperature and high vacuum state of each measured pressure side fluid is further supported.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment according to the present invention.

FIG. 2 is a side view showing the sealing cut of the pipe in the embodiment.

FIG. 3 is a cross-sectional view of a differential pressure detector common to the embodiment and the conventional example.

FIG. 4 is a cross-sectional view of a conventional example before fluid filling.

[Explanation of symbols]

 1 Differential Pressure Detection Section 2 Cover 2a Hole 4 Seal Diaphragm 5 Flange 5a Hole 6 Pipe 7 Intermediate 7a Hole 10 Pipe 11 Connection Fitting

Claims (3)

[Claims] 1. Each pressure relating to a differential pressure to be measured is transmitted to a differential pressure detecting section via an incompressible fluid enclosed in a diaphragm unit having a flange with a pressure receiving seal diaphragm and a connecting pipe. In the device, the differential pressure detecting device with a diaphragm unit is provided at an intermediate portion of the pipe, the opening being provided after degassing inside the pipe and enclosing the incompressible fluid. 2. The apparatus according to claim 1, wherein the opening is provided in an intermediate portion of the pipe, and the hollow portion of the pipe body is cut off after degassing and enclosing the incompressible fluid inside the pipe. A differential pressure detection device with a diaphragm unit, characterized in that 3. The differential pressure detecting device with a diaphragm unit according to claim 2, wherein the sealing cutting of the tube body comprises a pressure contact cutting step and a subsequent sealing welding step.