JP2007292479A - Bourdon-tube pressure gauge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bourdon-tube pressure gauge capable preventing hole failure of bourdon-tube connection in welding between a bourdon-tube and a tube support. <P>SOLUTION: The bourdon-tube pressure gauge includes the tube support 20 including a pressure inlet path 21 and supporting the bourdon-tube 10 and a tube coupling 30. The tube support 20 includes a screw hole 23, reaching the pressure inlet path 21 from its outer side face 22. The tube coupling 30 includes a tube jointing part 31 fitted inside a tube end 12 of the bourdon-tube 10, a screw tube part 32 projecting from a back surface 31b of the tube jointing part 31 and screwed into the screw hole 23, and a through-hole h<SB>1</SB>penetrating through a front-end face of the tube jointing part 31 and a front-end face of the screw tube 32. The inner circumferential surface 12a of the tube end 12 and the outer circumferential surface 31a of the tube jointing part 31 are welded. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Bourdon tube pressure gauge, and more particularly to a connection structure between a Bourdon tube and a tube support that supports the Bourdon tube.

In Japanese Patent Laid-Open No. 2000-280604, as a method of connecting the tube end (fixed end) of a Bourdon tube to a tube support in a Bourdon tube pressure gauge, the tube end is inserted into an oblique hole of the tube support. It is known that the inner peripheral surface of the hole and the outer peripheral surface of the pipe end are fixed by welding.
JP 2000-280604 A (FIG. 3)

  In general, although argon welding of a rolled copper product is easy, argon welding between a stainless steel Bourdon tube and a tube support requires a very advanced technique. That is, between a thin Bourdon tube and a block-shaped tube support, heat control is difficult due to a difference in heat capacity and the like, and a hole in the Bourdon tube is likely to be defective. In addition, although laser welding of stainless steel is easy, laser welding or beam welding cannot be used because light does not reach the depth of the weld joint surface.

  Therefore, in view of the above-described problems, a first object of the present invention is to provide a Bourdon tube pressure gauge that can suppress a hole defect in a Bourdon tube in welding between a Bourdon tube and a tube support. The second object of the present invention is to provide a Bourdon tube pressure gauge capable of using laser welding or beam welding in welding the Bourdon tube and a tube support.

  According to a first aspect of the present invention, there is provided a Bourdon tube pressure gauge having a pressure support passage and a tube support that supports the Bourdon tube, wherein the tube support has a screw hole reaching the pressure introduction passage from one outer surface thereof, A pipe joint that fits inside the pipe end of the pipe, a threaded pipe that protrudes from the back of the pipe joint and is screwed into a screw hole, and a penetration that penetrates the tip surface of the pipe joint and the tip surface of the screw pipe A pipe joint having a hole is provided, and the inner peripheral face of the pipe end and the outer peripheral face of the pipe joint are welded.

  When the threaded pipe part of the pipe joint is screwed into the screw hole of the pipe support and positioned, the pipe joint part of the pipe joint protrudes from one outer surface of the pipe support. The pipe end is press-fitted to weld the inner peripheral surface of the pipe end and the outer peripheral surface of the pipe joint. Since this pipe joint has a small heat capacity and can be made of a stainless steel product similar to a Bourdon pipe, it becomes easy to control the heat, and even a thin Bourdon pipe can suppress a hole defect. Also, when the tube ends are in close contact in the middle of the tube joint, there is a gap between the tube end and one outer surface of the tube support, so that light can easily reach the back of the joint surface, and laser welding or beam Welding can be used.

  The outer peripheral surface of the pipe joint is desirably a tapered surface that gradually narrows toward the tip surface. By pushing into the pipe joint at the pipe end, the pipe end deforms and adheres closely to the outer peripheral surface of the pipe joint, and stops at an intermediate position, so it is easy to secure a gap between the pipe end and one outer surface of the pipe support It is suitable for using laser welding or beam welding. Moreover, since the welding finish is beautiful, the polishing process after welding can be eliminated.

  According to a second means of the present invention, in the Bourdon tube pressure gauge having a tube support body that includes a pressure introduction path and supports the Bourdon tube, the tube support body reaches the pressure introduction path from a bottom surface of a recess provided on one outer surface thereof. A ring having a communication path and fitting the outer end of the Bourdon tube and the inner periphery of the ring; and welding the outer peripheral surface of the tube end to the inner peripheral surface of the ring. The inner circumferential surface is welded to each other.

  With the ring fitted in the recess of the pipe support, the pipe end and the ring's outer peripheral surface are welded to each other and the ring's outer peripheral surface and the inner peripheral surface of the ring are welded together. Weld the surrounding surfaces. Since this ring has a small heat capacity and can be made of a stainless steel product similar to a Bourdon tube, it is easy to control the heat, and even a thin Bourdon tube can suppress a hole defect. Further, light easily reaches the back of the joint surface, and laser welding or beam welding can be used.

  In the Bourdon tube pressure gauge according to the present invention, the Bourdon tube is not directly welded to the tube support, but can be welded using a medium member such as a pipe joint or a ring. Even a Bourdon tube can suppress perforations. Further, light easily reaches the back of the joint surface, and laser welding or beam welding can be used.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a perspective view showing a state before welding between a Bourdon tube and a tube support in a Bourdon tube pressure gauge according to Embodiment 1 of the present invention, and FIG. 1B is Z in FIG. FIG. 2A is a perspective view showing a state after welding of the Bourdon tube and the tube support, FIG. 2B is an enlarged view of a Z portion in FIG. FIG. 3A is a side view showing a pipe joint used for connection between the Bourdon tube and the tube support, and FIG. 3B is a cross-sectional view showing a connection portion between the Bourdon tube and the tube support.

  The Bourdon tube pressure gauge of this example includes a thin flat Bourdon tube 10 that is a copper-drawn product, a stainless steel tube support (frame) 20 that supports the tube, and a pipe joint 30 that is a copper-drawn product. . The tube support (frame) 20 has a pressure introduction path 21 connected to a pressure source and a screw hole 23 reaching the pressure introduction path 21 from the outer surface 22 as shown in FIG.

As shown in FIG. 3A, the pipe joint 30 projects from a pipe joint 31 fitted inside the pipe end (fixed end) 12 of the Bourdon pipe 10 and a screw hole 23 protruding from the back surface 31b of the pipe joint 31. and a threaded tube portion 32 which is screwed through hole h ₁ the distal end surface of the threaded tube portion 32 from the distal end surface of the pipe joint 31 penetrates into. The outer peripheral surface of the pipe joint portion 31 is a tapered surface that gradually narrows toward the tip surface.

  When the threaded pipe portion 32 of the pipe joint 30 is screwed into the screw hole 23 of the pipe support body 20 and positioned in the connection operation between the Bourdon tube 10 and the pipe support body 20, the pipe joint portion 31 of the pipe joint 30 becomes the pipe support body. 20, the tube end 12 of the Bourdon tube 10 is pushed into the tube joint 31. By this pushing, the pipe end 12 is deformed following the outer peripheral surface 31a of the pipe joint portion 31, and stops at a midway position. Since the tube end 12 does not reach the outer surface 22 and there is a gap, the inner peripheral surface 12a of the tube end 12 and the outer peripheral surface 31a of the tube joint portion 31 can be fixed by laser welding or beam welding. Since the pipe joint 30 has a small heat capacity and can be made of a stainless steel product similar to the Bourdon tube 10, heat control can be easily performed, and even a thin Bourdon tube 10 can suppress a hole defect.

  Since the screw pipe portion 32 is screwed into the screw hole 23, pressure leakage or the like can be avoided, but the back surface 31b and the outer side surface 22 of the pipe joint portion 31 may be welded if necessary.

  Since the outer peripheral surface 31a of the pipe joint portion 31 is a tapered surface, the adhesiveness of the pipe end 12 is improved, and the clearance between the pipe end 12 and the outer surface 22 can be easily secured, so that light can reach the back of the joint surface. Since it is easy to reach, it is suitable for using laser welding or beam welding. Moreover, since the welding finish is beautiful, the polishing process after welding can be eliminated.

  4 is a perspective view showing a state before welding between a Bourdon tube and a tube support in a Bourdon tube pressure gauge according to Embodiment 2 of the present invention, and FIG. 5 is a state after welding between the Bourdon tube and the tube support. FIG. 6 is a cross-sectional view showing a connection portion between the Bourdon tube and the tube support.

The Bourdon tube pressure gauge of this example includes a thin flat Bourdon tube 10 which is a copper-drawn product, a stainless steel tube support (frame) 20 'which supports the tube, and an oval ring 40 which is a copper-drawn product. Have As shown in FIG. 6, the tube support 20 ′ has a pressure introduction path 21 connected to a pressure source and a communication path h ₂ reaching the pressure introduction path 21 from the bottom surface of the oval recess 25 provided on the outer surface 22 thereof. ing.

  In the operation of connecting the Bourdon tube 10 and the tube support 20 ′, the oval ring 40 is fitted in the oval recess 25 of the tube support 20 ′, and the tube end 12 is fitted in the oval ring 40. The outer peripheral surface 12b of the tube end 12 and the inner peripheral surface 40a of the oval ring 40 are welded, and the outer peripheral surface 40b of the oval ring 40 and the inner peripheral surface 25a of the oval recess 25 are welded. Since the oval ring 40 has a small heat capacity and can be made of a stainless steel product similar to the Bourdon tube 10, heat control can be easily performed, and even a thin Bourdon tube 10 can suppress a hole defect. Further, light easily reaches the back of the joint surface, and laser welding or beam welding can be used.

(A) is a perspective view which shows the state before welding with a Bourdon tube and a pipe support body in the Bourdon tube pressure gauge which concerns on Example 1 of this invention, (B) is an enlarged view of the Z section in (A). . (A) The perspective view which shows the state after welding with the Bourdon tube and the tube support body, (B) is an enlarged view of the Z section in (A). (A) is a side view showing a pipe joint used for connection between the Bourdon tube and the tube support, and (B) is a cross-sectional view showing a connection portion between the Bourdon tube and the tube support. It is a perspective view which shows the state before welding of a Bourdon tube and a pipe support body in the Bourdon tube pressure gauge which concerns on Example 2 of this invention. It is a perspective view which shows the state after welding with the Bourdon tube and the tube support body. It is sectional drawing which shows the connection part of the Bourdon tube and the tube support body.

Explanation of symbols

10 ... Flat Bourdon tube 12 ... Tube end (fixed end)
12a ... pipe end inner peripheral surface 12b ... pipe end outer peripheral surface 20, 20 '... pipe support (frame)
DESCRIPTION OF SYMBOLS 21 ... Pressure introduction path 22 ... Outer side surface 23 ... Screw hole 25 ... Oval-shaped recess 30 ... Pipe joint 31 ... Pipe joint part 31a ... Outer peripheral surface 31b of a pipe joint part ... Back side 32 of a pipe joint part ... Screw pipe part 40 ... Oval ring h ₁ ... through hole h ₂ ... communication passage 40a ... inner peripheral surface 40b of oval ring ... outer peripheral surface of oval ring

Claims (3)

In a Bourdon tube pressure gauge having a tube support that supports a Bourdon tube with a pressure introduction path,
The tube support has a screw hole reaching from the outer surface to the pressure introduction path, a tube joint portion fitted inside the tube end of the Bourdon tube, protruding from the back surface of the tube joint portion, and screwed into the screw hole. A pipe joint having a threaded pipe portion to be attached and a through-hole penetrating the distal end surface of the threaded tube portion and the distal end surface of the threaded tube portion; an inner peripheral surface of the tube end; and an outer peripheral surface of the tube joint portion; Bourdon tube pressure gauge characterized by welding. 2. The Bourdon tube pressure gauge according to claim 1, wherein an outer peripheral surface of the tube joint portion is a tapered surface gradually narrowing toward the tip surface. In a Bourdon tube pressure gauge having a tube support that supports a Bourdon tube with a pressure introduction path,
The tube support has a communication path that reaches the pressure introduction path from the bottom surface of a recess provided on one outer surface thereof, and includes a ring that externally fits the tube end of the Bourdon tube and fits in the recess. The Bourdon tube pressure gauge is formed by welding the outer peripheral surface of the pipe end and the inner peripheral surface of the ring and welding the outer peripheral surface of the ring and the inner peripheral surface of the recess.

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