JP3032675U - Temperature sensitive tube - Google Patents

Abstract

(57) [PROBLEMS] To prevent gas leakage from occurring at a joint between a body and a head while keeping the manufacturing cost of the temperature sensitive tube at a low cost as usual. A tube body (4) formed by joining a body (2) and a head (3).
In the temperature sensitive tube 1 of the automatic temperature controller having the above, the end surface portion 2a of the body portion 2 of the tubular body 4 and the transition portion 2c from the end surface portion 2a to the side surface portion 2b are continuously curved. End face portion 2 of body portion 2
It is preferable that the radius of curvature R of the a and the transition portion 2c be twice to 1/2 the distance L from the joint between the body 2 and the head 3 to the side surface 2b of the body 2.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a temperature sensing tube used in an automatic temperature controller.

[0002]

[Prior art]

 When heating the inside of a greenhouse, etc., a heater, warm air blower, etc. are used, but in order to automatically adjust the air inside the greenhouse etc. to a predetermined temperature, these heaters A regulator is provided.

Among automatic temperature controllers, those that utilize pressure change (or volume change) of gas depending on temperature have been generally used conventionally. As shown in FIG. 5, in this automatic temperature controller 101, a micro switch 103 is arranged in a case 102, and a temperature sensitive tube 105 is supported on one side surface of the case 102 via a support member 104. A temperature setting dial 106 for setting a regulated temperature is arranged on the other side surface of the case 102, and a lead wire 107 is led out from the other side surface.

As shown in FIG. 6, the temperature-sensitive tube 105 includes a bellows 111 and an adjusting spring 112 disposed in a body 108 of a tubular body 110 composed of a body 108 and a head 109. The base end of the body 108 is closed by joining the opening to the base end of the body 108 by soldering or the like. Further, a set screw 113 is screwed onto the head portion 109 of the tubular body 110, the cap 114 is covered, and the tip portion of the head portion 109 is closed. Then, a cooling medium such as fluorocarbon (fluorocarbon) liquefied under high pressure is injected into the tubular body 110.

On the other hand, a working rod 115 is inserted and arranged across the case 102, the supporting member 104, and the temperature-sensitive tube 105, and the saucer portion 115 a of the working rod 115 is brought into contact with the bottom surface portion of the bellows 111 and The portion 115b is in contact with the operating portion 103a of the microswitch 103.

Therefore, when the temperature of the surrounding air rises and the vapor pressure of the CFCs vaporized in the temperature sensitive tube 105 increases, the bellows 111 and the adjusting spring 112 are compressed against the elastic force of the adjusting spring 112, The operating rod 115 moves so as to press the operating portion 103a of the microswitch 103. As a result, the contact point of the micro switch 103 is released, the power source of the heater, the hot air blower, etc. is turned off, and the air in the greenhouse is automatically adjusted to a predetermined temperature.

Here, as shown in FIG. 7, the tube body 110 of the temperature-sensitive tube 105 is made of hard brass after the body 108 and the head 109 made of brass, which are separately manufactured, are joined by soldering or the like. The end surface portion 108a of the body portion 108 has a substantially flat shape, and the transition portion 108c from the end surface portion 108a to the side surface portion 108b has a curved surface shape with a small radius of curvature.

[0008]

[Problems to be solved by the device]

 However, in the conventional temperature sensitive tube 105, when used for a relatively short period of time, gas leakage occurs at the joint between the body 108 and the head 109, and the accuracy of temperature control decreases, or in extreme cases. Had no temperature control at all. Gas leakage at the joint occurred even when the body 108 and the head 109 were completely soldered at the time of manufacturing.

As a measure to prevent such gas leakage, the body 108 and the head 109 are not separately manufactured, but are manufactured as an integral tube body 110, and are not joined by soldering or the like. Is most effective. However, in the case of manufacturing the integrated tubular body 110, the manufacturing cost of the temperature sensitive tube 105 is too high, which is not practical.

[0010]

[Means for Solving the Problems] Therefore, as a result of intensive research and study to solve the gas leakage at the joint between the body portion 108 and the head portion 109, the present inventor has found that such gas leakage is It has been found that it depends on the shape of the end face portion 108a of the body portion 108 and the transition portion 108c from the end face portion 108a to the side face portion 108b.

That is, when the temperature of the surrounding air rises and the vapor pressure of the CFCs vaporized in the temperature sensitive tube 105 rises, as shown by the arrow in FIG. 8, the end surface portion 108a of the body portion 108 and the moving portion are moved. Pressure is applied to the side surface 108c and the side surface portion 108b in the vertical direction. As a result, moments of axially upward force, radial outward force, and outward force of the body 108 are applied to the joint portion, the stress concentration in the joint portion becomes extremely high, and the joint state is poor. It was found that a gas leak was generated.

The present invention is based on such knowledge, and prevents the occurrence of gas leakage at the joint between the body and the head while keeping the manufacturing cost of the temperature sensitive tube at a low cost as usual. For this purpose, in a temperature-sensitive tube of an automatic temperature controller having a tubular body formed by joining a body and a head, an end face portion of the body of the tubular body and a transition portion from the end face portion to the side face portion. It is intended to provide a temperature-sensitive tube having a continuously curved surface. In addition, it is preferable that the radii of curvature of the end surface portion and the transition portion of the body portion be twice to 1/2 the distance from the joint portion between the body portion and the head portion to the side surface portion of the body portion.

[0013]

[Embodiment of device]

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

As shown in FIG. 1, the temperature-sensitive tube 1 of the present invention also has a bellows 5 and an adjusting spring 6 disposed in the body portion 2 of a tubular body 4 composed of a body portion 2 and a head portion 3, and a bellows The opening 5 is joined to the base end of the body 2 by soldering or the like to close the base end of the body 2. Further, a set screw 7 is screwed onto the head 3 of the tubular body 4, and a cap 8 is covered to close the tip of the head 3. Then, a refrigerant such as fluorocarbon (freon) liquefied under high pressure is injected into the closed tube body 4.

Here, as shown in FIG. 2, the tubular body 4 of the temperature-sensitive tube 1 is also hard chrome plated after the body 2 and the head 3 which are made of brass are joined by soldering or the like. However, it is characterized in that the end surface portion 2a of the body portion 2 and the transition portion 2c from the end surface portion 2a to the side surface portion 2b are continuously curved. The radius of curvature R of the end surface portion 2a and the transition portion 2c is preferably twice to 1/2 the distance L from the joint portion to the side surface portion 2b.

Also in the temperature-sensitive tube 1 of the present invention, when the temperature of the surrounding air rises and the vapor pressure of the fluorocarbon vaporized in the temperature-sensitive tube 1 increases, as shown by the arrow in FIG. Pressure is applied to the end face portion 2a, the moving portion 2c, and the side face portion 2b in the vertical direction. Then, although a moment of axially upward force, radial outward force, and outward force of the body portion 2 is applied to the joint portion, the end surface portion 2a and the transition portion 2c are continuously curved. Therefore, these forces and moments of force are significantly reduced compared to the conventional ones. Therefore, the degree of stress concentration at the joint is significantly reduced, the joint state is maintained well for a long time, and gas leakage does not occur.

The body portion 2 and the head portion 3 forming the tube body 4 can be manufactured by a method similar to the conventional method. As for the body portion 2, as shown in FIG. 4 (A), the plate material a fixed by the die 9 and the pressing body 10 is pushed in by the punch 11 or is brought into contact with the rotary die 12 as shown in FIG. 4 (B). It can be manufactured by pressing the plate material a with a spatula 13 and drawing it.

As described above, in the temperature-sensitive tube 1 of the present invention, the shape of the punch 11 or the rotary die 12 when the body 2 is drawn is changed to the end face portion 2a and the transition portion 2c of the body 2. Since it can only be molded into a curved surface continuously and the others can be manufactured by the same method as the conventional temperature-sensitive tube, the manufacturing cost is low as before.

In order to demonstrate the effect of the present invention, the temperature-sensitive tube 1 of the present invention and the conventional temperature-sensitive tube 105 were used to perform a comparative test for gas leakage. The temperature sensitive tube 1 of the present invention and the conventional temperature sensitive tube 105 are heated to 40 ° C., 50 ° C., 55 ° C., 60 ° C., 65 ° C., 70 ° C., 75 ° C., and held at that temperature for 1 hour, and then soldered. It was inspected whether or not a gas leak had occurred at the joint due to an injury. The temperature-sensitive tube 1 of the present invention and the conventional temperature-sensitive tube 105 were used 100 for each temperature condition.

[0020]

[Table 1]

The results of the comparative test are shown in Table 1. According to the temperature-sensitive tube 1 of the present invention, the joint state between the body portion 2 and the head portion 3 is kept good for a long time, and the joint portion It is understood that there is no gas leakage in.

[0022]

[Effect of device]

 In the temperature sensitive tube of the present invention, the end face and transition of the body of the tubular body are continuously curved, and the degree of stress concentration at the joint is markedly reduced. The joined state between the portion and the head is well maintained, and the occurrence of gas leakage at the joined portion can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a temperature sensing tube of the present invention.

FIG. 2 is an explanatory view showing a method for joining the body and the head of the temperature sensing tube of the present invention.

FIG. 3 is an explanatory view showing a direction in which a gas pressure is applied to an end surface portion, a transition portion and a side surface portion of a body portion of a temperature sensing tube of the present invention.

FIG. 4 is an explanatory view showing a method for forming a body portion of a tubular body,
(A) is an explanatory view showing a molding method using a die, a pressing body and a punch, and (B) is a molding method using a rotary die and a spatula.

5A is a partially cut front view of a conventional automatic temperature controller, and FIG. 5B is a side view thereof.

FIG. 6 is a cross-sectional view of a conventional temperature sensitive tube.

FIG. 7 is an explanatory diagram showing a method for joining a body and a head of a tubular body of a conventional temperature-sensitive tube.

FIG. 8 is an explanatory view showing an application direction of gas pressure at an end surface portion, a transition portion and a side surface portion of a body portion of a conventional temperature-sensitive tube.

[Explanation of symbols]

 1 Temperature Sensitive Pipe 2 Body 2a End Face 2b Side 2c Transition 3 Head 4 Tubular Body

Claims (2)

[Scope of utility model registration request] 1. A temperature-sensitive tube of an automatic temperature controller having a tubular body formed by joining a body and a head, wherein an end face portion of the body of the tubular body and a transition portion from the end face portion to the side face portion are provided. A temperature-sensitive tube characterized by being continuously curved. 2. The radii of curvature of the end surface portion and the transition portion of the body portion are twice to 1/2 the distance from the joint portion between the body portion and the head portion to the side surface portion of the body portion. The temperature-sensitive tube according to claim 1, characterized in that.