JP5340080B2 - Bourdon tube and thermometer equipped with this bourdon tube - Google Patents

Description

  The present invention relates to a Bourdon tube and a thermometer including the Bourdon tube.

  Conventionally, a pressure-type thermometer using a Bourdon tube is known as a thermometer for measuring the temperature of a measurement site (see, for example, Patent Document 1). The thermometer described in Patent Document 1 includes a temperature sensing unit set at a measurement site, a conduit connected to the temperature sensing unit via a connection tube, and a Bourdon tube connected to the conduit.

  Conventionally, for example, a Bourdon tube 101 shown in FIG. 5 is known as a Bourdon tube for a thermometer. As shown in FIG. 5A, the Bourdon tube 101 is formed in a substantially 3/4 arc shape as a whole. In addition, the Bourdon tube 101 has a direction orthogonal to the circumferential direction centering on the center of curvature of the Bourdon tube 101 formed in a substantially arc shape and the flat direction of the Bourdon tube 101 (vertical direction in FIG. 5C) ( An intermediate position in the left and right direction in FIG. 5C is crushed in the flat direction, and a filling space 101a filled with fluid is disposed at both ends in the left and right direction in FIG. 5C. Yes. 5B is a view showing the Bourdon tube 101 from the LL direction of FIG. 5A, and FIG. 5C is a cross-sectional view of the MM cross section of FIG.

JP-A-9-15059

  As described above, in the thermometer described in Patent Document 1, the Bourdon tube and the conduit are connected. However, Patent Document 1 does not disclose a specific configuration of a connection portion between a Bourdon tube and a conduit.

  Accordingly, an object of the present invention is to propose a specific configuration of a connecting portion of a Bourdon tube formed of copper or a copper alloy with a conduit.

In order to solve the above-mentioned problems, the Bourdon tube of the present invention has a temperature sensing part attached to a part to be measured, two conduits connected at one end to the temperature sensing part, and the other end of the conduit. A Bourdon tube used in a pressure thermometer equipped with a Bourdon tube, which is formed of copper or a copper alloy and is formed in a substantially arc shape centering on a predetermined curvature center. A crushing portion formed by crushing an intermediate position in a first direction substantially orthogonal to a circumferential direction centered on the center and a flat direction of the Bourdon tube in the flat direction, and a fluid disposed at both ends of the first direction And a fluid filling portion in which a space for filling is formed, and one end side of the Bourdon tube in the circumferential direction is inserted into each of the other end sides of the two conduits. two conduit insertion portion is made form, two Each of the tube insertion portion and connected to each of the two fluid-filled portion disposed at both ends of the first direction, the inner diameter of the conduit insert portion is larger than the inner diameter of the fluid-filled portion, and the outer conduit It is characterized by the size corresponding to the diameter.

  Here, when the material of the Bourdon tube is steel, the material of the conduit connected to the Bourdon tube is generally steel, and the Bourdon tube and the conduit are fixed to each other by welding. On the other hand, when the material of the Bourdon tube is copper or a copper alloy, the following problems occur when the Bourdon tube and the conduit are fixed to each other by welding. In other words, since the thermal conductivity of copper is relatively high, if the Bourdon tube and conduit made of copper or a copper alloy are fixed to each other by welding, the applied welding heat will rapidly diffuse into the Bourdon tube. The problem is that the weldability of the welded part is poor and defects such as poor bonding are likely to occur, and because the coefficient of linear expansion of copper is relatively large, the Bourdon tube and conduit formed of copper or copper alloy are welded together. If fixed, the deformation of the Bourdon tube during welding becomes large, and there arises a problem that the shrinkage strain at the time of cooling concentrates on the welded portion and cracks are likely to occur in the welded portion. Therefore, when the material of the Bourdon tube is copper or a copper alloy, it is preferable that the Bourdon tube and the conduit are fixed to each other by brazing such as soldering.

  In the Bourdon tube of the present invention, the conduit insertion portion into which the other end side of the conduit is inserted is formed on one end side of the Bourdon tube and connected to the fluid filling portion, and the inner diameter of the conduit insertion portion is set to the outer diameter of the conduit. It has a corresponding diameter. Therefore, even if the material of the Bourdon tube is copper or a copper alloy and one end side of the Bourdon tube and the other end side of the conduit are fixed to each other by brazing, the inside of the conduit or the filling space is brazed. Can be stopped between the outer peripheral surface of the conduit and the inner peripheral surface of the conduit insertion portion. Therefore, it is possible to appropriately fix the bourdon tube and the conduit formed of copper or a copper alloy while preventing clogging of the bourdon tube and the conduit.

  In the present invention, for example, the inner diameter of the conduit insertion portion is substantially the same as the outer diameter of the conduit.

  The Bourdon tube of the present invention can be used for a thermometer including a temperature sensing part and a conduit. With this thermometer, it is possible to appropriately fix the bourdon tube and the conduit formed of copper or a copper alloy while preventing clogging of the bourdon tube and the conduit. In this thermometer, for example, the conduit is formed of copper or a copper alloy, and the Bourdon tube and the conduit are fixed to each other by brazing.

  As described above, according to the present invention, it is possible to appropriately fix the bourdon tube and the conduit formed of copper or a copper alloy while preventing clogging of the bourdon tube and the conduit.

It is a front view for demonstrating schematic structure of the thermometer concerning embodiment of this invention. It is a perspective view of the Bourdon tube shown in FIG. It is a figure for demonstrating the structure of the Bourdon tube shown in FIG. 1, (A) is a front view, (B) is a figure which shows a Bourdon tube from the EE direction of (A), (C) is (A). Sectional drawing of the FF cross section of (A), (D) is sectional drawing of the GG cross section of (A). It is sectional drawing for demonstrating the structure of the connection part of the Bourdon tube and conduit shown in FIG. It is a figure for demonstrating the structure of the Bourdon tube concerning a prior art, (A) is a front view, (B) is a figure which shows a Bourdon tube from the LL direction of (A), (C) is (A). It is sectional drawing of MM cross section of. It is sectional drawing for demonstrating the structure of the connection part of the Bourdon tube and conduit | pipe concerning a prior art.

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

(Schematic configuration of thermometer)
FIG. 1 is a front view for explaining a schematic configuration of a thermometer 1 according to an embodiment of the present invention.

  The thermometer 1 of this embodiment is a pressure thermometer using a Bourdon tube 2. In addition to the Bourdon tube 2, the thermometer 1 includes a temperature sensing portion 3 attached to a temperature measurement portion and two conduits 4. The proximal end side of the conduit 4 is connected to the temperature sensing unit 3, and the distal end side of the conduit 4 is connected to the proximal end of the Bourdon tube 2. Further, the distal end portion of the Bourdon tube 2 is connected to a pointer 6 via a displacement magnifying mechanism 5. Further, a part of the distal end side of the conduit 4, the Bourdon tube 2, the displacement enlarging mechanism 5, the pointer 6, and the like are arranged inside a case 7 formed in a bottomed cylindrical shape.

  The base end of the Bourdon tube 2 is open. The tip of the Bourdon tube 2 is closed. The temperature sensing unit 3 is formed, for example, in a bottomed cylindrical shape, and a conduit 4 is connected to the opening side (the upper side in FIG. 1). The conduit 4 is a metal tube formed in an elongated cylindrical shape. The conduit 4 in this embodiment is made of copper or a copper alloy. The detailed configuration of the Bourdon tube 2 and the configuration of the connecting portion between the Bourdon tube 2 and the conduit 4 will be described later.

  The pointer 6 rotates along a scale on a scale plate (not shown). A pinion 8 is fixed to a rotation shaft that is a rotation center of the pointer 6. The displacement enlarging mechanism 5 fulfills the function of enlarging the amount of displacement at the tip of the Bourdon tube 2 and transmitting it to the pointer 6. A distal end portion of the Bourdon tube 2 is fixed to an input portion of the displacement magnifying mechanism 5. A sector gear 9 that meshes with the pinion 8 is disposed at the output portion of the displacement magnifying mechanism 5.

  The thermometer 1 of the present embodiment is a liquid pressure thermometer in which the inside of the Bourdon tube 2, the temperature sensing unit 3, and the conduit 4 is filled with a liquid such as alcohol. In the thermometer 1, when the temperature around the temperature sensing unit 3 changes, the liquid in the temperature sensing unit 3 expands and contracts, and the liquid in the temperature sensing unit 3 expands and contracts. The pressure change is transmitted to the inside of the Bourdon tube 2 through the conduit 4. The thermometer 1 is a vapor in which the inside of the temperature sensing unit 3 is filled with a low-temperature volatile liquid such as ether and its vapor and the inside of the Bourdon tube 2 and the conduit 4 is filled with a low-temperature volatile liquid vapor. A pressure-type thermometer may be used. The thermometer 1 may be a gas pressure type thermometer in which the inside of the Bourdon tube 2, the temperature sensing unit 3, and the conduit 4 is filled with a gas such as an inert gas.

(Configuration of Bourdon tube and connection between Bourdon tube and conduit)
FIG. 2 is a perspective view of the Bourdon tube 2 shown in FIG. 3A and 3B are diagrams for explaining the configuration of the Bourdon tube 2 shown in FIG. 1, wherein FIG. 3A is a front view, and FIG. 3B is a diagram showing the Bourdon tube 2 from the EE direction of FIG. (C) is sectional drawing of the FF cross section of (A), (D) is sectional drawing of the GG cross section of (A). FIG. 4 is a cross-sectional view for explaining the configuration of the connecting portion between the Bourdon tube 2 and the conduit 4 shown in FIG.

  The Bourdon tube 2 is made of copper or a copper alloy. The Bourdon tube 2 of this embodiment is made of beryllium copper that can be quenched. The Bourdon tube 2 is formed in a substantially C shape as shown in FIG. Specifically, the Bourdon tube 2 is formed in a substantially 3/4 arc shape centered on a predetermined center of curvature O.

  Further, the Bourdon tube 2 has a first direction (FIG. 3A) substantially orthogonal to a circumferential direction centering on the center of curvature O and a flat direction of the Bourdon tube 2 (vertical direction in FIG. 3C). A crushing portion 2a formed by crushing an intermediate position in the direction perpendicular to the paper surface, the left and right directions in FIGS. 3B and 3C) in the flat direction, and a fluid filling portion 2b disposed at both ends in the first direction. The Bourdon tube 2 is formed so that the two fluid filling portions 2b are connected by the crushing portion 2a. In addition, a filling space 2c filled with a liquid such as the above-described alcohol is formed inside the fluid filling portion 2b. That is, the cross-sectional shape of the Bourdon tube 2 in the direction perpendicular to the circumferential direction of the Bourdon tube 2 with the center of curvature O as the center is as shown in FIG. It has a substantially glasses shape in which the filling space 2c to be filled is arranged.

  The crushing part 2a is formed in the whole area in the circumferential direction of the Bourdon tube 2 centering on the center of curvature O. The fluid filling part 2b is formed in a substantially cylindrical shape. Further, the fluid filling portion 2b is formed in the entire area in the circumferential direction of the Bourdon tube 2 excluding the base end side of the Bourdon tube 2.

  On the proximal end side of the Bourdon tube 2, two conduit insertion portions 2d into which the distal end side of the conduit 4 is inserted are formed so as to be connected to the fluid filling portion 2b. The conduit insertion portion 2d is formed in a substantially cylindrical shape, and the inner diameter of the conduit insertion portion 2d is larger than the inner diameter of the fluid filling portion 2b. Further, the inner diameter of the conduit insertion portion 2 d is a size corresponding to the outer diameter of the conduit 4. Specifically, the inner diameter of the conduit insertion portion 2 d is substantially the same as the outer diameter of the conduit 4. More specifically, the outer diameter of the conduit 4 is slightly smaller than the inner diameter of the conduit insertion portion 2d. Further, the inner peripheral side of the conduit insertion portion 2d is connected to the filling space 2c. Moreover, in the left-right direction of FIG. 3D, the width of the crushing part 2a formed between the two conduit insertion parts 2d is narrower than the width of the crushing part 2a of the other part.

  In this embodiment, the inner diameter of the fluid filling portion 2b and the inner diameter of the conduit 4 are substantially equal. However, the inner diameter of the fluid filling portion 2b and the inner diameter of the conduit 4 are different. Also good. Further, in this embodiment, the outer diameter of the fluid filling portion 2b and the outer diameter of the conduit 4 are substantially equal. However, the outer diameter of the fluid filling portion 2b and the outer diameter of the conduit 4 are the same. May be different. However, the outer diameter of the conduit 4 is formed larger than the inner diameter of the fluid filling portion 2b.

  The Bourdon tube 2 and the conduit 4 are fixed to each other by brazing using a solder 11 such as solder or silver solder (that is, an alloy having a lower melting point than the Bourdon tube 2 and the conduit 4 as a base material). Specifically, as shown in FIG. 4, in the state where the distal end side of the conduit 4 is inserted into the conduit insertion portion 2d, the wax 11 is applied to the proximal end of the Bourdon tube 2, and the applied wax 11 is cured. The Bourdon tube 2 and the conduit 4 are fixed to each other. The bourdon tube 2 and the conduit 4 may be fixed using joints (not shown) disposed on the outer peripheral side of the conduit insertion portion 2d and the outer periphery of the conduit 4, or without using the joint. The Bourdon tube 2 and the conduit 4 may be fixed.

(Main effects of this form)
As described above, in this embodiment, the conduit insertion portion 2 d into which the distal end side of the conduit 4 is inserted is formed on the proximal end side of the Bourdon tube 2. Further, the outer diameter of the conduit 4 is slightly smaller than the inner diameter of the conduit insertion portion 2d. Therefore, even when the Bourdon tube 2 and the conduit 4 formed of copper or a copper alloy are fixed to each other by brazing, the brazing 11 flows into the interior of the conduit 4 or into the filling space 2c. It becomes possible to stop between the inner peripheral surface of the part 2d and the outer peripheral surface of the conduit 4.

  On the other hand, in the case of the conventional Bourdon tube 101 in which the conduit insertion portion 2d is not formed, when the Bourdon tube 101 and the conduit 4 are fixed to each other by brazing, for example, as shown in FIG. The wax 11 may flow into the inside of the conduit 4 or the filling space 101a from the gap between the end and the tip of the conduit 4. In this embodiment, it is possible to stop the wax 11 from flowing into the inside of the conduit 4 or into the filling space 2 c between the inner peripheral surface of the conduit insertion portion 2 d and the outer peripheral surface of the conduit 4. In addition, it is possible to appropriately fix the Bourdon tube 2 formed of copper or a copper alloy and the conduit 4 while preventing clogging of the conduit 4.

  In this embodiment, the brazing 11 flowing between the inner peripheral surface of the conduit insertion portion 2d and the outer peripheral surface of the conduit 4 can increase the fixing strength between the Bourdon tube 2 and the conduit 4.

(Other embodiments)
In the embodiment described above, the outer diameter of the conduit 4 is slightly smaller than the inner diameter of the conduit insertion portion 2d. However, the wax 11 flows into the inside of the conduit 4 and into the filling space 2c. As long as it can be stopped between the inner peripheral surface and the outer peripheral surface of the conduit 4, the outer diameter of the conduit 4 may be significantly smaller than the inner diameter of the conduit insertion portion 2d. That is, the inner diameter of the conduit insertion portion 2d can prevent the wax 11 from flowing into the inside of the conduit 4 or the filling space 2c between the inner peripheral surface of the conduit insertion portion 2d and the outer peripheral surface of the conduit 4. In addition, it may be formed in a size corresponding to the outer diameter of the conduit 4. Further, in the above-described form, the conduit insertion portion 2d is formed in a substantially cylindrical shape, but the conduit insertion portion 2d is formed in a substantially polygonal cylinder shape such as a substantially rectangular tube shape or a hexagonal tube shape or a substantially elliptical tube shape. May be.

  In the above-described embodiment, the Bourdon tube 2 is used in a pressure thermometer, but the Bourdon tube 2 may be used in a pressure gauge.

DESCRIPTION OF SYMBOLS 1 Thermometer 2 Bourdon tube 2a Crushing part 2b Fluid filling part 2c Filling space 2d Pipe insertion part 3 Temperature sensing part 4 Conduit O Curvature center

Claims (4)

Used in a pressure thermometer comprising a temperature sensing part attached to a part to be measured, two conduits connected at one end to the temperature sensing part, and a Bourdon tube connected at the other end of the conduit Bourdon tube,
It is formed of copper or a copper alloy and is formed in a substantially arc shape centered on a predetermined center of curvature.
A crushing portion formed by crushing an intermediate position in a first direction substantially orthogonal to a circumferential direction around the center of curvature and a flat direction of the Bourdon tube in the flat direction; A fluid filling portion is formed in which a filling space arranged at both ends and filled with fluid is formed, and
At one end of the Bourdon tube in the circumferential direction, two conduit insertion portion, each of the other end of the two said conduit is inserted is made form,
Each of the two conduit insertion portions is connected to each of the two fluid filling portions disposed at both ends in the first direction,
The Bourdon tube characterized in that an inner diameter of the conduit insertion portion is larger than an inner diameter of the fluid filling portion and is a size corresponding to an outer diameter of the conduit.   The Bourdon tube according to claim 1, wherein the inner diameter of the conduit insertion portion is substantially the same as the outer diameter of the conduit.   A thermometer comprising the Bourdon tube according to claim 1, the temperature sensing unit, and the conduit. The conduit is formed of copper or a copper alloy;
The thermometer according to claim 3, wherein the conduit and the Bourdon tube are fixed to each other by brazing.

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