JP5469922B2 - Fusible stopper - Google Patents

Description

  The present invention relates to a fusible plug, and more particularly to a fusible plug used for a high temperature and high pressure liquid reservoir, an accumulator or the like in a refrigeration apparatus.

  Conventionally, in high temperature and high pressure liquid reservoirs and accumulators in a refrigeration apparatus, fusible stoppers have been used to prevent damage to the main body due to an increase in pressure in the apparatus (accumulator or the like) or an increase in refrigerant temperature. This fusible plug is composed of a through-hole drilled in the main body and a solder alloy that fills the through-hole while ensuring airtightness. The solder alloy filled in the holes is melted and the internal coolant is discharged to the outside, thereby preventing damage to the apparatus.

  However, if the solder alloy filled in the through-hole in the main body contains harmful substances such as lead and cadmium, when the device to which the fusible stopper is applied is disposed of, the lead and cadmium are dissolved in water. However, there was a problem of contaminating groundwater.

  Therefore, in Patent Document 1, two types of solder alloys filled in the main body are selected from the group consisting of tin (Sn), bismuth (Bi), indium (In), zinc (Zn), and gallium (Ga). A fusible stopper made of the above metal has been proposed.

JP 2002-115940 A

  However, the fusible plug described in Patent Document 1 does not contaminate groundwater or the like even if the device to which the fusible plug is applied is disposed of, but has a creep characteristic in a temperature range of 58 ° C to 65 ° C. Since it is bad, there is a possibility that the solder alloy may be pushed out by the pressure in the refrigeration apparatus before the fusible stopper is actuated when the inside of the refrigeration apparatus reaches a predetermined temperature, and there is room for improvement.

  In recent years, carbon dioxide instead of chlorofluorocarbon has been used as a refrigerant in consideration of preventing the destruction of the ozone layer. However, when carbon dioxide is used as a refrigerant, the inside of the refrigeration apparatus has a higher pressure than before. Therefore, development of a solder alloy having creep characteristics that can withstand a high-pressure atmosphere has been demanded.

  Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and does not contain harmful substances such as lead, and has excellent creep characteristics in a temperature range of 58 ° C. to 65 ° C. The purpose is to provide a stopper.

In order to achieve the above object, the fusible plug of the present invention, the through hole in the plug-shaped body, silver 1.5 wt% to 2.5 wt% or less, 35 wt% or less of bismuth 33% by mass or more, indium It is characterized by being filled with a solder alloy which is 63 mass% or more and 65 mass% or less and the total content of silver, bismuth and indium is 100 mass% .

  And according to the present invention, since the solder alloy is composed of silver, bismuth and indium, it does not contain harmful substances such as lead and cadmium, and even if the device to which the fusible stopper is applied is disposed of, groundwater etc. There is no contamination. In addition, the solder alloy exhibits excellent creep characteristics in the temperature range of 58 ° C. to 65 ° C., and can be prevented from being pushed out by the internal pressure of the apparatus before reaching the operating temperature. Furthermore, the solder alloy can be melted in a temperature range of 69 ° C. to 75 ° C. (temperature range to be operated), and the original function required for the fusible stopper is not impaired. In addition, by producing a solder alloy with the above composition, the fluidity when filling the body is increased, and generation of voids (bubbles) and variation in strength can be suppressed.

  In the fusible plug, the solder alloy can be filled into a through hole having an inner diameter of 4 mm to 7 mm in the main body. If the inner diameter of the through hole does not reach 4 mm, it is difficult to fill the through hole with a solder alloy. If the inner diameter of the through hole exceeds 7 mm, the above-described excellent creep characteristics cannot be realized.

  In the fusible stopper, the solder alloy can be filled into a through hole having an axial total length of 25 mm or more in the main body. Thereby, excellent creep characteristics can be obtained in the above temperature range.

  As described above, according to the present invention, it is possible to provide a fusible stopper excellent in creep characteristics in a temperature range of 58 ° C. to 65 ° C. without containing harmful substances such as lead.

It is a partially broken sectional view which shows 1st Embodiment of the fusible stopper concerning this invention. It is a partially broken sectional view which shows 2nd Embodiment of the fusible stopper concerning this invention.

  Next, an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment of a fusible plug according to the present invention. The fusible plug 1 is formed in a plug shape, and has a wrench engaging portion 2a, a freezing unit, a main body 2 having a through hole inside. Threaded connection with a condenser or liquid receiver of the high-pressure side accessory of the device, or a female thread portion provided in the liquid reservoir or accumulator (hereinafter referred to as “connected portion”) on the high-pressure side. And a part of the piping of the refrigeration apparatus (when the inside of the refrigeration apparatus is hot and high in pressure, the fusible plug operates and the refrigerant is discharged to the outside, the workers around the refrigeration apparatus A second male screw portion 2c for screwing and connecting with a female screw portion for guiding the refrigerant to a place where there is no influence on the inner ring, an annular groove 2d formed on the inner wall surface of the main body 2, and a through hole filled, A low melting point alloy 3 that melts when the inside of the apparatus reaches a predetermined temperature is provided.

  The main body 2 is formed so that the total length L thereof is 25 mm or more and the diameter φa of a through hole provided therein is 4 mm or more and 7 mm or less. By these, the filling of the solder alloy to the through-hole of the main body 2 is easy, and excellent creep characteristics can be obtained in a temperature range of 58 ° C to 65 ° C.

  The annular groove 2 d is formed in an annular shape on the inner wall surface of the main body 2 and plays a role of increasing the bonding area between the main body 2 and the low melting point alloy 3. As a result, the adhesive strength between the main body 2 and the low melting point alloy 3 is strengthened, the peeling of the low melting point alloy 3 is prevented, and the low melting point alloy 3 pops out vigorously when the pressure in the apparatus rises rapidly. To prevent.

The low melting point alloy 3 is 1.5% by mass to 2.5% by mass of silver (Ag), 33% by mass to 35% by mass of bismuth (Bi), 63% by mass to 65% by mass of indium (In) , And it is a solder alloy whose total content of this silver, bismuth, and indium is 100 mass% . The composition of the low melting point alloy 3 is a characteristic part of the present invention, whereby excellent creep characteristics can be obtained in the above temperature range. Further, when the low melting point alloy 3 is generated with the above composition, the fluidity when filling the main body 2 is increased, and generation of voids (bubbles) and variation in strength can be suppressed.

  In the above embodiment, the fusible plug 1 is connected to the connected portion of the refrigeration apparatus and the pipe via the first male screw portion 2b and the second male screw portion 2c, respectively. In the case of a unit that is not necessary, the fusible plug 11 as shown in FIG. 2 is formed, and the male screw portion 12 is screwed with the female screw portion provided at the connected portion of the refrigeration apparatus, whereby the fusible plug 11. Can also be installed. In addition, it is the component of the soluble stopper 11, Comprising: The component which has the same function as the soluble stopper 1 of FIG. 1 attaches | subjects the same code | symbol.

  In each of the five devices, the internal pressure of the device was maintained at 4.2 MPa, and the entire soluble stopper was immersed in the glycerin solution, and then the temperature inside the device was increased at a rate of temperature increase of 1 ° C./min. The composition of the low melting point alloy 3 was silver (2% by mass), bismuth (34% by mass), and indium (64% by mass). As a result of the test, the low melting point alloy 3 was melted in the temperature range of 69 ° C. to 75 ° C. in any of the soluble stoppers.

  In each of the above devices, the entire soluble stopper was immersed in a glycerin solution, and then the low melting point alloy 3 was tested for popping out with the soluble stopper attached to the device for two months. At this time, the internal pressure of the apparatus was maintained at 4.2 MPa, and the temperature in the apparatus was set to 65 ° C., which is lower than the temperature at which the fusible plug should operate. As a result of the test, the low-melting point alloy 3 did not pop out in any of the soluble stoppers.

  As described above, according to the present invention, (a) the low melting point alloy 3 melts in the temperature range of 69 ° C. to 75 ° C., and operates reliably in the temperature range to be operated. In a low temperature range (58 ° C. to 65 ° C.), it was possible to realize a fusible stopper satisfying both requirements that the low melting point alloy 3 does not pop out due to the internal pressure (4.2 MPa) of the refrigeration apparatus.

DESCRIPTION OF SYMBOLS 1 Fusible plug 2 Main body 2a Wrench engaging part 2b 1st male thread part 2c 2nd male thread part 2d Annular groove 11 Solubilized plug 12 Male thread part

Claims (3)

In the through-hole in the plug-shaped body, 1.5% by mass to 2.5% by mass of silver, 33% by mass to 35% by mass of bismuth, 63% by mass to 65% by mass of indium, and the silver and bismuth And a fusible plug characterized by being filled with a solder alloy having a total content of 100% by mass of indium .   2. The fusible plug according to claim 1, wherein the solder alloy is filled in a through-hole having an inner diameter of 4 mm to 7 mm in the main body.   3. The fusible plug according to claim 1, wherein the solder alloy is filled in a through-hole having a total axial length of 25 mm or more in the main body.

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