JP3426167B2 - Pressure gauge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Bourdon tube type pressure gauge, for example, a small pressure gauge used for a pressure accumulator or the like.

[0002]

2. Description of the Related Art In a conventional pressure gauge using a spiral Bourdon tube, as shown in FIGS. 10 and 11, the Bourdon tube 17 and the joint 12 in the pressure gauges 80 and 90 are directly joined, and the joining thereof is performed. The method is soldering depending on the materials of the Bourdon tube 17 and the joint 12,
Brazing with metal and welding are selected. That is, as shown in FIG. 10, when the materials of the Bourdon tube 17 and the joint 12 are both brass (BS) type, soldering is applied to the E portion of the cylindrical base end portion 17A of the Bourdon tube 17 on the case body 11 side. When the material of the Bourdon tube 17 is stainless steel (SUS) and the material of the joint 12 is brass, silver brazing is similarly applied to the E portion. on the other hand,
As shown in FIG. 11, when the materials of the Bourdon tube 17 and the joint 12 are both stainless steel, welding is performed at the opening portion F of the cylindrical base end portion 17A of the Bourdon tube 17, and the material of each of these members. For example, in the case of a pressure gauge for a fire extinguisher, it is selected according to the type of fire extinguishing liquid.

When the case body 11 is made of stainless steel and the joint 12 is made of brass, the case body 11 and the joint 12 are usually fixed by caulking at the G portion (see FIG. 10). For example, in a pressure gauge for fire extinguisher, since airtightness is required by its technical standard, fixing by caulking alone is not enough,
Further, a mold material, an adhesive agent, or the like is applied to the joint portion H between the joint 12 and the case body to improve airtightness (see FIG. 10).

[0004]

However, in order to assemble a pressure gauge using such a conventional joining method,
Different joining methods must be adopted depending on the material of the joint, the Bourdon tube, etc., and automation of the production line is difficult. In particular, the soldering and brazing process between the Bourdon tube and the joint is different from the welding process, and the insertion of solder or brazing material at the joint, application of flux, heating by gas or high frequency,
There has been a problem that a plurality of steps such as flux removal (washing with hot water) and drying are required, and automation of a pressure gauge manufacturing process including such steps requires a great equipment cost.

Further, in fixing the case main body and the joint by caulking as described above, although the adhesive is applied to improve the airtightness, the reliability of the airtightness is lower than that of welding or soldering. There was a problem of becoming.

In order to solve such a problem, the materials of the Bourdon tube, the joint, and the case body may be unified, for example, to stainless steel having high corrosion resistance, and all of them may be joined by welding. Has a problem that the cost is higher than that of brass system, and is not a sufficient solution.

An object of the present invention is to provide a pressure gauge capable of joining by welding even if the joint and the Bourdon tube are made of different materials, and achieving automation of the production line and reduction of the production cost by unifying the assembly equipment and the assembly process. To provide.

[0008]

The present invention is intended to achieve the above object by inserting a pipe made of a material different from that of the joint between the joint portion of the joint and the Bourdon tube. Specifically, the invention according to claim 1 has a case main body having a joint connected to the measured portion, a transparent cover attached to the case main body to form a storage space together with the case main body, and the storage. A Bourdon tube which is housed in a space and into which a pressure from the measured portion is introduced, and a pipe made of a material different from that of the joint is inserted into the joint, and the pipe is inserted into the joint. The pressure gauge is characterized in that the gap between the joint and the joint is sealed with a sealing material, and the pipe and the Bourdon tube are welded.

In the present invention, as the material of the joint, a material which can reduce the cost can be adopted, and, for example, brass metal can be adopted. On the other hand, as the material of the pipe, a material having welding suitability can be adopted, and for example, stainless metal can be adopted. Further, as the material of the Bourdon tube, a material having a suitability for welding with a pipe can be adopted, and for example, a stainless metal can be adopted. Examples of the sealing with the sealing material include brazing for melting and sealing and joining dissimilar metals having a lower melting point than those of the Bourdon tube and the pipe. Alloys may be mentioned. Further, the case main body having the joint in the present invention includes one in which the joint and the case main body are integrated, and one in which the joint and the case main body are separate.

According to the present invention, a pipe made of a material different from that of the joint is inserted into the joint in advance and sealed, and the pipe and the Bourdon tube are joined by welding. Therefore, even when the material of the joint cannot be welded to the Bourdon tube, it is possible to perform the welding process with the pipe interposed. As a result, the conventional soldering and brazing processes can be omitted from the pressure gauge manufacturing process, making it easy to automate the pressure gauge manufacturing line by unifying the assembly equipment and The manufacturing cost can be reduced because the step of is unnecessary.

The invention according to claim 2 is the pressure gauge according to claim 1, characterized in that the case body is welded to one end of the pipe.

According to this invention, since the case body of the pressure gauge is welded and fixed to the pipe interposed between the joint and the Bourdon tube, the joint and the case body cannot be fixed by direct welding. However, instead of fixing by caulking or the like, fixing by welding becomes possible. As a result, the joint, the Bourdon tube, and the case body can be fixed only by welding through the pipe, which simplifies the assembly equipment and is advantageous for automation of the production line. In addition, since welding is used for joining, the airtightness inside the pressure gauge can be improved, and the process for improving airtightness required by the caulking method, such as the adhesive and molding material, is no longer necessary. It is possible to simplify the process and reduce the manufacturing cost.

According to a third aspect of the invention, in the pressure gauge according to the first or second aspect, a needle seat for fixing a pointer portion indicating a pressure value is welded to the Bourdon tube, and the needle seat is attached to the needle seat. Is a pressure gauge having the pointer portion attached thereto.

In the above, if the pointer portion is directly fixed to the Bourdon tube without passing through the needle seat, the pointer portion faces radially outward of the spiral portion, and accordingly, the scale must be formed further outside the pointer portion. I won't. On the other hand, by fixing the pointer portion to the Bourdon tube via the needle seat as in the present invention, the pointer portion can be arranged so as to cover the front side of the spiral portion, that is, the transparent cover side. Therefore, compared with the case where the pointer portion is directly attached to the Bourdon tube, no space is required in the radial direction of the spiral portion. As a result, the pressure gauge can be downsized.

According to a fourth aspect of the present invention, in the pressure gauge according to any one of the first to third aspects, the transparent cover is provided with a pressure display scale for displaying the pressure detected by the Bourdon tube. It is a pressure gauge that is characterized. Examples of the transparent cover in the present invention include those in which only the movable range of the pointer portion is transparent and the scale is described on other portions. The shape of the transparent portion is not particularly limited as long as the pointer portion can be confirmed.

According to the present invention, since the transparent cover also serves as the scale plate, the number of parts required for assembling the pressure gauge can be reduced, and the assembling process can be simplified and the manufacturing cost can be reduced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention.
A pressure gauge 10 according to the embodiment is shown. 1 and 2
As shown in FIG. 1, the pressure gauge 10 includes a case body 11 made of stainless steel, and the case body 11 is raised around the bottom surface portion 11A having a hole in the center and the entire circumference of the bottom surface portion 11A. In addition, the front end portion is formed into an overall concave shape having an edge portion 11B which is slightly recessed inward. And such a pressure gauge 10 is attached to the fire extinguisher main body 70 which is a measured part.

The case body 11 has a male screw portion 1 on one end side.
2A, a brass joint 12 having a polygonal head 12B on the other end side and having a hole in the center is attached via a stainless pipe 13. Here, the pipe 13 is inserted into the joint 12, and the gap 18 between the joint 12 and the pipe 13 is sealed with a sealing material, that is, is sealed with silver brazing A over the entire circumference (FIG. 3). (See (b)). Further, at one end of pipe 13 (the right end in FIG. 1), case body 11 and pipe 13 are fixed over the entire circumference by welding joint B by welding (see FIG. 3A). With these silver brazing A and welded joint B, the case main body 11, joint 12, pipe 13
Are united. The male thread portion 12 of the joint 12
The case body 11, that is, the pressure gauge 10 can be attached to the fire extinguisher body 70 by screwing A onto the female screw portion 70A provided in the fire extinguisher body 70.

Inside the case body 11, the case body 1
A metal disc-shaped scale plate 14 is provided which is in contact with the bottom surface portion 11A of No. 1 and in which a hole is formed in the central portion where pressure indication, material, date of manufacture, etc. are described. Further, a transparent cover 15 made of glass or synthetic resin is provided so as to press the scale plate 14 from above (left side in FIG. 1).

The transparent cover 15 includes a flat plate portion 151 for confirming a pointer portion 20 described later from the outside, and the flat plate portion 151.
And an edge portion 152 that is formed so as to surround the outer periphery thereof, and a protrusion portion 15A that bulges outward is formed on the outer periphery of the edge portion 152. The outer periphery of the protrusion 15A is in close contact with the inner periphery of the edge 11B of the case body 11, and an O-ring 16 is mounted in the gap between the base end of the protrusion 15A and the edge 11B of the case body 11. The pressure gauge 10 is kept airtight. In addition, a through hole 15B for decompression having a predetermined size is formed in the center of the surface of the transparent cover 15. The through hole 15B is formed by the adhesive tape 19
It is closed with and is kept to be hermetically sealed under normal conditions. In the above, the case body 11 and the transparent cover 15
The space surrounded by is the storage space S, and this storage space S
A Bourdon tube 17 made of stainless steel or the like is housed inside.

The Bourdon tube 17 is formed by having a cylindrical base end portion 17A having a pressure introducing hole inside and a spiral portion 17B continuous with the base end portion 17A.
B is stored in the storage space S, the cylindrical base end portion 17A is inserted through the bottom surface portion 11A of the case body 11 and the pipe 13, and the end portion faces the inside of the fire extinguisher body 70. Here, the left end portion in FIG. 1 of the cylindrical base end portion 17A of the Bourdon tube 17 is fixed to the pipe 13 by the welded joint C (see FIG. 3B). A sealing portion D sealed by welding or the like is provided near the end of the spiral portion 17B, and the pointer portion 20 is spot welded to the tip side of the sealing portion D in the spiral portion 17B. It is attached by laser welding or the like.

The pressure gauge 10 thus constructed is assembled as follows. Pre-made brass joint 12
Insert stainless steel pipe 13 inside,
In the gap 18 formed between the pipe 13 and the pipe 13, sealing with a sealing material, that is, silver brazing A is performed, and the joint 12
And the pipe 13 are integrated. Next, the holes inside the joint 12, that is, the hole of the pipe 13 and the hole formed in the central portion of the bottom surface portion 11A of the case body 11 made of stainless steel are arranged so as to coincide with each other. The portion of the portion 11A that is in contact with the periphery of the hole is joined by welding joint B over the entire circumference.

Next, after the scale plate 14 is attached to the bottom surface portion 11A of the case body 11, the pointer portion 20 is previously welded or the like.
The cylindrical base end portion 17A of the stainless steel Bourdon tube 17 to which is attached is inserted into the pipe 13, and the opening edge portion of the cylindrical base end portion 17A and the remaining one end of the pipe 13 are welded over the entire circumference. Join by joining C. further,
The transparent cover 15, the O-ring 16 and the like are attached by a normal method to complete the assembly of the pressure gauge 10. The above series of steps is performed by an automatic manufacturing line.

Next, a method of using the pressure gauge 10 will be described.
The male screw portion 12A of the joint 12 of the pressure gauge 10 is screwed into the female screw portion 70A of the fire extinguisher body 70, and the head portion 12B is turned by a wrench or the like to be attached to the fire extinguisher body 70. Then, the fire extinguisher body 70 is filled with pressure (gas + extinguishing agent). The pressure is filled into the spiral portion 17B from the opening of the cylindrical base end portion 17A of the Bourdon tube 17, expands the spiral portion 17B, and moves the pointer portion 20 to a predetermined position. The pointer 20 indicates the pressure inside the fire extinguisher body 70.

According to the first embodiment as described above, the following effects can be obtained. (1) A material different from that of the brass joint 12, that is, a stainless pipe 13 is inserted into the joint 12 in advance and sealed with silver brazing A, and the pipe 13 and the stainless Bourdon tube 17 are welded and joined by welding C It will be fixed by. Therefore, even with a material that cannot be directly welded to the stainless steel Bourdon tube 17 such as the brass joint 12,
It becomes possible to join by the welding process with the pipe 13 interposed. This makes it possible to omit the soldering and brazing processes as alternative processes when welding is not possible as in the past from the pressure gauge assembly process, making it easy to automate the pressure gauge manufacturing line by unifying the assembly equipment. Therefore, the manufacturing process can be reduced because the process unique to brazing is not necessary. In particular, it is suitable for mass production by reducing the manufacturing cost, and can reduce the product cost. Therefore, it is particularly effective as a pressure gauge for a fire extinguisher as in the present embodiment.

(2) Stainless steel pipe 1 interposed between brass joint 12 and stainless steel Bourdon tube 17
3, since the stainless steel case body 11 of the pressure gauge 10 is fixed by the welding joint B, even if the joint 12 and the case body 11 cannot be fixed directly by welding, they are fixed by welding instead of mechanical fixing by caulking or the like. Is possible. As a result, the joint 12, the Bourdon tube 17, and the case body 11 can be fixed only by welding via the pipe 13, which simplifies the assembly equipment and is advantageous in automating the production line. Further, since the joining is performed by welding, the airtightness inside the pressure gauge 10 can be improved, and the step for improving the airtightness by the adhesive, the molding material, etc., which is necessary in the case of the caulking method, is unnecessary. It is possible to simplify the assembly process and reduce the manufacturing cost.

(3) Since the stainless steel pipe 13 is used, the stainless bourdon tube 17 can be used regardless of the material of the joint 12, so that the parts can be shared and the cost can be reduced. (4) Since the brass joint 12 that is cheaper than stainless steel is used, the manufacturing cost of the pressure gauge 10 can be reduced. (5) Since the stainless steel Bourdon tube 17 having high corrosion resistance is used, the pressure gauge 10 is less likely to deteriorate and can be used for a long time.

(6) Since the through hole 15B for depressurization is provided on the surface of the transparent cover 15, the leakage can be easily known from the trace of leakage on the transparent adhesive tape 19. (7) The pointer portion 20 is the spiral portion 17B of the Bourdon tube 17
Since it is attached to the tip side of the sealing portion D in the above, when the pointer portion 20 is attached to the Bourdon tube 17 by welding or the like, even if a hole is opened, the pressure introduced into the Bourdon tube 17 is not It has no effect.

4 and 5 show a pressure gauge 30 according to a second embodiment of the present invention. In the present embodiment and other embodiments described later, only the portions different from the first embodiment will be described in detail, the same members and the same structures will be denoted by the same reference numerals, and detailed description thereof will be omitted. To simplify.

The pressure gauge 30 according to the present embodiment is the first
Similar to the embodiment, the case body 11, the joint 12, and the pipe 1
3, the transparent cover 15, the Bourdon tube 17, etc., the gap 38 between the joint 12 and the pipe 13 in the pressure gauge 30 is on the opposite side of the gap 18 in the first embodiment, that is, in FIG. It is provided near the right end of the middle pipe 13. In the gap 38, the joint 12 and the pipe 13 are sealed and joined by the silver brazing A described above (see FIG. 5A). The other constituent members and the joining method of the members are the same as those in the first embodiment.

The pressure gauge 30 constructed as described above is assembled in the same manner as in the first embodiment except for the positions of the gap 38 and the silver brazing A. Also,
The usage method is also the same as in the first embodiment.

The effects of (1) to (7) in the first embodiment can also be obtained by the second embodiment as described above.
Furthermore, in this embodiment, the following effects are obtained. (8) Since the silver brazing A is performed on the case body 11 side and the silver brazing A is not exposed to the outside, the silver brazing A is not damaged when being attached to or detached from the fire extinguisher body 70, and is sealed for a long time. Can maintain a stopped state.

6 and 7 show a pressure gauge 40 according to the third embodiment of the present invention. The pressure gauge 40 includes a brass case body 41 having a concave cross section and an outer peripheral portion formed in a polygonal shape, and has a male screw portion 42A on a side of the fire extinguisher body 70, which is a measured portion of the case body 41. A joint 42 is provided. Here, the case body 4
1 and the joint 42 are integrally formed and are substantially one member. Further, on the step portion 41A formed in the opening of the case body 41, the O-ring 16 is provided over the entire circumference thereof.
Is mounted, and the transparent cover 45 is mounted from above the O-ring 16 (left side in FIG. 7) so as to maintain airtightness. Here, the member for ensuring the airtightness is not limited to the O-ring 16, and for example, packing or the like may be used. Further, the bottom surface portion 41B of the case main body 41 is provided with a through hole 41C for decompression having a predetermined size. The through hole 41C is formed by the adhesive tape 4 made of aluminum or the like.
It is closed at 9, and is kept airtight in a normal state.

A stainless steel pipe 13 is inserted into the hole formed inside the joint 42, and the joint 42 and the pipe 13 are separated from each other by a gap 1 formed between the joint 42 and the pipe 13.
It is sealed all over by A with silver brazing in 8. Further, since the case body 41 and the joint 42 are integrally formed as described above, the airtightness at the connecting portion between the case body 41 and the joint 42 is ensured, so that the other end of the pipe 13 is sealed. Not not.

The Bourdon tube 17 is housed in the storage space S surrounded by the case body 41 and the transparent cover 45, and the cylindrical base end portion 17A of the Bourdon tube 17 is inserted into the pipe 13 to extinguish the fire. It is fixed at one end on the main body 70 side by welding joint C by welding with the pipe 13. Also, the spiral portion 17B of the Bourdon tube 17
Then, the needle seat 5 made of stainless steel or the like is provided on the tip side of the sealing portion D.
1 is joined by welding or the like. The needle seat 51 has a joint portion 51B joined to the spiral portion 17B, and a ring-shaped portion which is orthogonal to the joint portion 51B and covers the front surface of the spiral portion 17B, that is, the transparent cover 45 side. 51A, and is formed in an L-shaped cross section. Further, on the disc-shaped portion 51A, a circular pointer portion 50 made of synthetic resin or the like for indicating a pressure value is attached by an adhesive or the like.

In the above, the transparent cover 45 is composed of two members, that is, a scale plate 45A in which a pressure display scale or the like is described in glass or synthetic resin and a cover member 45B made of transparent glass or synthetic resin. Scale plate 45A
In addition to the pressure display scale and the like, a transparent window 45C is provided in a part thereof, and the pointer portion 50 can be confirmed through this transparent window 45C. The shape of the transparent window 45C may be any shape as long as the pointer portion 50 can be confirmed.

The pressure gauge 40 thus constructed is assembled as follows. In advance, the stainless steel pipe 13 is inserted into the brass joint 42, and silver brazing A is performed in the gap 18 formed between the joint 42 and the pipe 13 so that the joint 42 and the pipe 13 are integrated. . At this time, since the case body 41 and the joint 42 are integrally formed, the case body 41, the joint 42, and the pipe 1
3 becomes one.

Next, the cylindrical base end portion 17A of the stainless steel Bourdon tube 17 to which the needle seat 51 is attached in advance is inserted into the pipe 13 by spot welding, laser welding, or the like, and the opening of the cylindrical base end portion 17A is performed. The portion and one end of the pipe 13 are joined by welding joint C over the entire circumference.
After that, the pointer portion 50 is attached onto the needle seat 51 with an adhesive or the like applied to the back surface thereof. Further, the transparent cover 45, the O-ring 16 and the like are attached by a usual method to complete the assembly of the pressure gauge 40. In addition, the above series of steps,
It can be performed by an automatic manufacturing line as in the first embodiment. The method of using the pressure gauge 40 is the same as that of the first embodiment, except that the outer edge of the case body 41 is rotated by a wrench or the like to attach the pressure gauge 40.

According to the third embodiment as described above, the first
The same effects as (1), (3) to (7) in the embodiment are obtained. Further, there are the following effects. (9) Since the case body 41 and the joint 42 are integrally formed, that is, as one member, the number of parts can be reduced,
The cost can be reduced. In addition, the case body 41
Since the welding process of the pipe 13 and the pipe 13 is not required, the manufacturing process can be simplified and the cost can be reduced. (10) The pointer portion 50 is attached to the Bourdon tube 17 via the needle seat 51.
By fixing the pointer portion 50 to the front side of the spiral portion 17B, that is, the transparent cover 45 side, the pointer portion 50 can be arranged. Therefore, compared to the case where the pointer portion 20 is directly attached to the Bourdon tube 17 as in the first embodiment, no space is required in the radial direction of the spiral portion 17B. As a result, the pressure gauge 40 can be downsized.

(11) Case body 41 and joint 42
Is made of brass, which is cheaper than stainless steel, so that the manufacturing cost can be reduced. (12) Since one member of the transparent cover 45 is the scale plate 45B, the scale plate made of another material is not required, the number of parts can be reduced, and the measured pressure value can be easily confirmed.

8 and 9 show a pressure gauge 60 according to a fourth embodiment of the present invention. The pressure gauge 60 includes a case body 61 made of stainless steel and having a concave cross section, and a step 61 formed in an opening of the case body 61.
An O-ring 16 is placed on B, and a transparent cover 65 made of glass or synthetic resin on which pressure indicating scales and the like are formed is placed on the O-ring 16 so as to maintain airtightness. There is. In addition, in the storage space S surrounded by the transparent cover 65 and the case body 61, the Bourdon tube 17
The needle seat 51 and the pointer portion 50 having the same structure as the third embodiment are attached to the Bourdon tube 17.

In the above, the transparent cover 65 has a pressure display scale formed on the inner surface side thereof by printing or the like, and a part of the scale has a transparent window 65C on which no scale is formed.
It is said that. The pointer portion 50 is provided through the transparent window 65C.
Can be confirmed. The case body 6
The means for joining the respective members of the joint 1, the joint 12, the pipe 13, and the Bourdon tube 17 are the same as in the first embodiment.

In the pressure gauge 60 having the above-described structure, the joint 12, the pipe 13, the case body 61, and the Bourdon tube 17 are joined and assembled in the same manner as in the first embodiment. , Again, Bourdon tube 1
The attachment of the needle seat 51 to the needle seat 7 and the attachment of the pointer portion 50 to the needle seat 51 are performed in the same manner as in the third embodiment. The method of using the pressure gauge 60 is the same as in the first embodiment.

According to the fourth embodiment as described above, the same effects as (1) to (5) and (7), (10) and (12) in the first and third embodiments can be obtained. Further, there are the following effects. (13) The transparent cover 65 with the pressure display scale is
Unlike the third embodiment, since it is composed of one member, the number of parts can be further reduced, so that the assembly process can be simplified and the manufacturing cost can be reduced.

The present invention is not limited to the above-described embodiments, and modifications and improvements within a range in which the object of the present invention can be achieved are included in the present invention. For example, in each of the above embodiments, the joints 12, 42 and the pipe 13 are
Although the gap 18 formed between and is sealed by silver brazing A, it is not limited to this, and may be sealed by brazing using a dissimilar metal having a lower melting point than the joints 12, 42 and the pipe 13. Good. Further, although the material of the pipe 13 is stainless steel, the material is not limited to this, and it is possible to seal the joints 12 and 42 with a sealing material and weld the case bodies 11 and 41 and the Bourdon tube 17 to each other. , Other metals may be used.

In each of the above embodiments, the Bourdon tube 17
Of the pointer portion 2 on the tip side of the sealing portion D of the spiral portion 17B of
0 (first and second embodiments) and the needle seat 51 (third and fourth embodiments) were welded, but not limited to this, the sealing portion D is the end, and the pointer is located closer to the center than this. The portion 20 and the needle seat 51 may be welded. However, as in each embodiment, the sealing portion D
It is preferable that the pressure measurement is not affected even if a minute hole or the like is formed in the spiral portion 17B during welding by attaching the filter to the tip end side. Further, the structures, shapes, materials and the like of the needle seat 51 and the pointer portion 50 are not limited to those in the third and fourth embodiments, and any structure that indicates the measured pressure may be used.

[0047]

According to the present invention, a pipe made of a material different from that of the joint is inserted into the joint in advance and sealed, and the pipe and the Bourdon tube are joined by welding. Therefore, even when the material of the joint cannot be welded to the Bourdon tube, it is possible to perform the welding process with the pipe interposed. As a result, the conventional soldering and brazing processes can be omitted from the pressure gauge manufacturing process, making it easier to automate the pressure gauge manufacturing line by unifying the assembly equipment. Since it is unnecessary, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a pressure gauge according to a first embodiment of the present invention.

FIG. 2 is a front view of the embodiment shown in FIG.

FIG. 3 is a partially enlarged view of the embodiment of FIG.

FIG. 4 is a sectional view showing a pressure gauge according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged view of the embodiment shown in FIG.

FIG. 6 is a front view showing a pressure gauge according to a third embodiment of the present invention.

7 is a cross-sectional view of the embodiment of FIG.

FIG. 8 is a front view showing a pressure gauge according to a fourth embodiment of the present invention.

9 is a sectional view corresponding to FIG. 7 in the embodiment of FIG.

FIG. 10 is a cross-sectional view of a conventional pressure gauge corresponding to FIG.

FIG. 11 is a sectional view of a conventional pressure gauge corresponding to FIG.

[Explanation of symbols]

10, 30, 40, 60 Pressure gauge 11, 41, 61 Case body 12, 42 joint 13 pipes 14, 45A, 65 scale plate 15, 45 Transparent cover 18, 38 gap 20, 50 Pointer 51 needle seat 70 Fire extinguisher body that is the part to be measured A With silver braze as a sealant Welding by B and C welding S storage space

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-51-81174 (JP, A) actual open-up 51-87482 (JP, U) actual open-up 48-112387 (JP, U) actual open-up 48- 69083 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01L 7/04

Claims (4)

(57) [Claims] 1. A case main body having a joint connected to a measured part, a transparent cover attached to the case main body to form a storage space together with the case main body, and the measured target housed in the storage space. A pressure gauge having a Bourdon tube into which pressure from the section is introduced, wherein a pipe made of a material different from that of the joint is inserted into the joint, and a gap between the pipe and the joint is sealed. A pressure gauge characterized by sealing with a material and welding the pipe and the Bourdon tube. 2. The pressure gauge according to claim 1, wherein the case main body is welded to one end of the pipe. 3. The pressure gauge according to claim 1 or 2, wherein a needle seat for fixing a pointer portion indicating a pressure value is welded to the bourdon tube, and the pointer portion is attached to the needle seat. A pressure gauge characterized by that. 4. The pressure gauge according to any one of claims 1 to 3, wherein the transparent cover is formed with a pressure display scale for displaying the pressure detected by the Bourdon tube. Pressure gauge.