JPH0629707Y2 - Fluid pressure detector for piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fluid pressure detection device for a pipe suitable for being installed in a fluid pipe such as a clean room where cleanliness is particularly required.

[Background Art and Problems] In the field of semiconductor industries such as IC and LSI, it is required to work in a clean room in which fine particles and dust are excluded, and the manufacturing work environment and conditions are becoming more and more severe.

Special gas used in semiconductor manufacturing is introduced into the clean room from the outside through piping.For pressure detection in the gas piping line, conventionally, an Aneroid type Bourdon tube pressure gauge was screwed in the middle of the gas piping line.
The flow gas in the pipe was introduced into the Bourdon pipe to detect the pressure.

However, with such a structure, when the pressure gauge is screwed in the middle of the gas pipe line, there is a problem that dust generated by the screwing enters the pipe. Also, regarding the structure of the pressure gauge itself, the surface roughness of the inside of the Bourdon tube, which is the element, is rough, and the Bourdon tube itself has a dead structure, so that gas accumulates at these points,
There was a problem that a so-called dead zone was formed.

The presence of such a dead zone causes the generation of fine particles of a molecular unit from the uneven surface of the gas contacting surface in the Bourdon tube due to the retention of the flowing gas, which is mixed into the flowing gas. In addition, the circulating gas that enters the Bourdon tube is
When the vapor deposition line is evacuated during vacuum vapor deposition of a predetermined gas onto the device, the vapor may gradually flow out and diffuse, and may mix with the gas to be vapor-deposited and cause defects.

Therefore, there is a demand for a pressure detection device suitable for use in the semiconductor industry field such as LSI.

[Object of the Invention] The object of the present invention is to meet such a demand, a dead zone which is a retention part is not formed in the pipe, and the sealing property in the mounting part is maintained while maintaining high detection accuracy. It is an object of the present invention to provide a fluid pressure detection device for a pipe that can significantly increase the pressure.

[Means and Actions for Solving Problems] Therefore, in the present invention, the problems associated with the structure of the Bourdon tube type pressure gauge itself, that is, the occurrence of the fluid retention portion due to the surface roughness and the retention in the Bourdon tube are considered. In order to solve this problem, a pressure sensor that detects the fluid pressure as an electrical signal is used, and the gap between the pressure sensor and the pressure sensor that is created when the pressure sensor is attached to the pressure detection port of the pipe is sealed with a metal seal member. The thrust bearing is interposed between the cap nut to be held and the pressure sensor to prevent the pressure sensor and the seal member from twisting due to the rotational force when tightening the cap nut, while preventing the detection accuracy of the pressure sensor from lowering due to twisting. The metallic seal member is designed to exhibit the original high sealing performance.

Specifically, in a fluid pressure detection device for a pipe that detects a fluid pressure flowing through a fluid flow path in a pipe, a tubular protrusion is integrally formed in the middle of the pipe, and the pipe of the pipe is formed in the protrusion. A pressure detection port that communicates with the fluid flow channel is formed, and a pressure sensor that detects the fluid pressure as an electrical signal is stored in the pressure detection port while facing the fluid flow channel of the pipe. A metal seal member is provided between the pressure sensor and the seat for receiving the pressure sensor, and a cap nut for holding the pressure sensor is screwed onto the outer periphery of the protrusion, and the cap nut is held between the cap nut and the pressure sensor. In addition to the thrust bearing, a cap nut is formed in the center of which a conduit drawn from the pressure sensor is inserted and an insertion hole having a diameter larger than the outer diameter of the conduit is formed.

[Embodiment] FIG. 1 shows an embodiment of the present invention. In the figure, a pressure detecting port 5 communicating with the fluid flow path 3 of the pipe 1 and having stepped seats 4A and 4B is provided in the tubular rising protrusion 2 provided in the middle of the pipe 1. It is open. The inner surface of the fluid flow path 3 is ultra-precision finished to prevent generation of a retention portion due to its surface roughness. In addition, the seat 4A. A pressure sensor 6 for detecting the fluid pressure flowing in the fluid flow path 3 as an electrical signal is housed between the 4B and a seal between the body portion 6A of the pressure sensor 6 and the seat 4A for receiving it. A metal C ring 7 as a member is inserted.

The pressure sensor 6 has a cylindrical body portion 6A that is in contact with the seat 4A of the pressure detection port 5 via the C ring 7.
And a pressure detection end 6B provided at the tip of the body 6A
And a conduit 6C for sending the electric signal detected by the pressure detecting end 6B to the outside. The body portion 6A includes a collar that is positioned on the receiving seat 4B of the pressure detecting port 5. A cylindrical cap 8 is attached to the surface of the flange opposite to the surface in contact with the receiving seat 4B. Further, the pressure detecting end 6B at the tip is constituted by, for example, a so-called diaphragm type strain gauge in which a strain gauge is vapor-deposited on a diaphragm surface, and the inside of the fluid passage 3 is covered with the diaphragm surface so as to cover the pressure detecting port 5. Is faced with. In this case, the end facing the fluid flow path 3 is formed in a shape that does not resist the fluid, that is, a spherical shape. Further, the tip of the conduit 6C is connected to a pressure indicator (not shown).

A male screw 2A is formed on the outer periphery of the rising projection 2, and a cap nut 10 having a through hole 9 having a diameter larger than the outer diameter of the conduit 6C is screwed into the male screw 2A. Have been combined. A thrust bearing 12 is interposed between an inner end surface of the cap nut 10 and the cap 8 of the pressure sensor 6 via a cylindrical presser 11. The components of the thrust bearing 12, that is, the balls, the pair of rings, etc., are the cylindrical tubular retainer 1 having elasticity.
Held as one by 3 and its Ritina 13
It is attached to the presser foot 11 via.

Now, in the state where the thrust bearing 12 is not provided, when the cap nut 10 is screwed, its rotational force is transmitted to the pressure sensor 6 and the C ring 7 via the presser 11 and the cap 8, and as a result, the pressure sensor 6 and the C ring 7 Is twisted. When the pressure sensor 6 is twisted, the twisting reduces the detection accuracy, and when the C ring 7 is twisted,
The gap between the pressure sensor 6 and the seat 4A of the pressure detection port 5 cannot be completely sealed. However, in this embodiment,
Since the rotational force of the cap nut 10 is not transmitted to the members after the presser 11 by the action of the thrust bearing 12, there is no decrease in the detection accuracy due to the twist of the pressure sensor 6,
Further, since the C ring 7 is not twisted, it can be tightened by the tightening force only in the axial direction.

Therefore, according to the present embodiment, the pressure sensor 6 for detecting the fluid pressure as an electric signal is used in place of the conventional Bourdon tube pressure gauge, so that there is a problem with the structure of the Bourdon tube pressure gauge itself. In other words, there is no generation of a retention part caused by the surface roughness and the retention inside the Bourdon tube. In addition, since the inner surface of the fluid flow path 3 of the pipe 1 is ultra-precision finished, it is possible to prevent the retention portion from occurring also from this point.

In addition, a metal C ring 7 is inserted between the pressure sensor 6 and the receiving seat 4A of the pressure detection port 5 that receives the pressure sensor 6.
Since the gap between the two is sealed by the above, the gap between the pressure detection port 5 and the pressure sensor 6 can be sealed. In particular, since the metal C ring 7 is used, it is possible to secure a high sealing property that cannot be obtained with a normal rubber seal member, and it becomes a source of generation of fine dust as compared with the rubber seal member. Since there is no such thing, a high degree of cleanliness can be secured.

Further, the presser 11 is provided between the cap nut 10 and the pressure sensor 6.
Since the thrust bearing 12 is interposed via the pressure bearing 6, the rotational force of the cap nut 10 is not transmitted to the pressure sensor 6 and the C ring 7 via the retainer 11. Therefore, it is possible to prevent the detection accuracy from deteriorating due to the twist of the pressure sensor 6, and since the C ring 7 is not twisted, it is possible to exhibit the original high sealing performance of the metal C ring 7. Moreover, since the constituent elements of the thrust bearing 12 are held in the predetermined positions by the retainer 13, not only can the assembly be performed easily, but also the thrust bearing 12
The function of can be surely demonstrated.

In FIG. 1, when connecting other pipes to both ends of the pipe 1, it is necessary to connect both pipes by welding or the like. In the connection by welding, if the inner surface of the fluid flow path 3 is subjected to corrosion-resistant treatment (treatment when the fluid is corrosive gas), there is a problem that the treatment is wasted. FIGS. 2 and 3 eliminate this point. Incidentally, FIG. 2 and FIG.
In the description of the drawings, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 2, external threads 21, 2 are formed on the outer peripheral surfaces of both ends of the T joint 20.
2 is formed, and the cap nut 2 is attached to each of the male screws 21 and 22.
3, 24 are screwed together, and the cap nuts 23, 24 connect the pipes 25, 26 to both ends of the T joint 20.
In this case, a metal C is provided between one end face of the T-joint 20 and the end face of the pipe 25 and between the other end face of the T-joint 20 and the end face of the pipe 26.
Thrust bearing 2 in which rings 27, 28 are retained by retainers 31, 32 between cap nut 23 and pipe 25 and between cap nut 24 and pipe 26.
9 and 30 are inserted respectively. Therefore, even if the cap nuts 23 and 24 are screwed together, the rotational force due to the screw is applied to the pipe 2
5, 26 and the metal C-rings 27, 28 are not transmitted, so that the sealing effect can be perfected.

In FIG. 3, the thrust bearings 29, 30 with the retainers 31, 32 in FIG. 2 are replaced with ball bearings 41. With this, the same effect as that of FIG. 2 can be obtained.

Further, in each of the above embodiments, the diaphragm type strain gauge is used as the pressure sensor, but the pressure sensor is not limited to this, and any pressure sensor capable of detecting the fluid pressure as an electrical signal may be used.

Further, in each of the above-described embodiments, the fluid is described as a gas, but the invention can be sufficiently applied to a fluid such as a liquid.

[Effects of the Invention] As described above, according to the present invention, the occurrence of the stagnant portion is small,
In addition, since it is possible to improve the sealing performance while maintaining high detection accuracy, it is possible to install it in piping such as in a clean room where cleanliness is required, without particles or dust being mixed into the fluid. It is possible to provide a fluid pressure detection device for piping suitable for the above.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIGS. 2 and 3 are sectional views showing other embodiments of the present invention. 1 ... Piping, 2 ... Standing protrusion, 3 ... Fluid flow path, 5 ...
... pressure detection port, 6 ... pressure sensor, 7 ... metal C ring, 9 ... insertion hole, 10 ... cap nut, 12 ... thrust bearing, 13 ... retainer, 20 ... T joint.

Continuation of the front page (56) Bibliography Sho 50-124978 (JP, U) Steady Sho 48-2876 (JP, U) Japanese Patent Sho 39-25259 (JP, B1) Real Sho 47-554 (JP , Y1) Actual public Sho 52-14444 (JP, Y2)

Claims (5)

[Scope of utility model registration request] 1. A fluid pressure detection device for a pipe, which detects a fluid pressure flowing in a fluid flow path in the pipe, wherein a tubular protrusion is integrally formed in the middle of the pipe, and the pipe is provided in the protrusion. A pressure detection port that communicates with the fluid flow channel is formed, and a pressure sensor that detects the fluid pressure as an electrical signal is stored in the pressure detection port while facing the fluid flow channel of the pipe. A metal seal member is provided between the pressure sensor and the seat for receiving the pressure sensor, and a cap nut for holding the pressure sensor is screwed onto the outer periphery of the protrusion, and the cap nut is held between the cap nut and the pressure sensor. A fluid pressure detecting device for a pipe, characterized in that a thrust bearing is interposed in the pipe, and a conduit drawn from the pressure sensor is inserted in the center of the cap nut and an insertion hole having a diameter larger than the outer diameter of the conduit is formed. . 2. A fluid pressure detecting device for a pipe according to claim 1, wherein the pressure sensor is a diaphragm type strain gauge. 3. Claim for utility model registration claim 1 or 2
A fluid pressure detecting apparatus for a pipe according to the above item, wherein the seal member is a metal C ring. 4. Claims 1 to 3 of the utility model registration claim.
In the fluid pressure detection device for piping according to any one of items,
A fluid pressure detecting device for a pipe, comprising a retainer for holding components such as balls and rings of the thrust bearing at predetermined positions. 5. Claims 1 to 4 of the utility model registration claim
In the fluid pressure detection device for piping according to any one of items,
A fluid pressure detection device for a pipe, characterized in that the inner surface roughness of the pipe is ultra-precision finished.