JP2002115940A - Fusible stop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that the conventional fusible stop contains Pb, Cd, etc., in a low melting point alloy and hence there is fear that Pb or Cd dissolved by acidic rains to pollute underground waters when a refrigerator, etc., with the fusible stop fails to be disabled, and hence the fusible stop is filled up in the ground. SOLUTION: The fusible stop uses a low melting point alloy to be filled in the body which is composed of two or more kinds of metals selected among Sn, Bi, In, Zn and Ga, not containing Pb or Cd at all, and hence if a refrigerator, etc., fails to result in that the fusible stop is filled up in the ground, it never pollutes underground waters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chiller unit,
The present invention relates to a fusible plug installed in a packaged air conditioner, a refrigerator, and the like (hereinafter, referred to as a refrigerator, etc.).

[0002]

2. Description of the Related Art Refrigerators and the like compress a refrigerant to a high temperature and a high pressure by compressing the refrigerant, and then release heat to a medium to be heated by a condenser, and condense and liquefy into a high temperature and a high pressure liquid refrigerant. . The liquid refrigerant is collected in a liquid pool and decompressed by a throttle device. The refrigerant, which has been decompressed and easily evaporated, takes heat from the medium to be cooled in the evaporator, evaporates itself, and becomes a low-temperature, low-pressure gas refrigerant. After that, the non-evaporated liquid refrigerant is recovered by the accumulator and returned to the compressor. Normally, fusible plugs are installed in equipment such as liquid pools and accumulators that become high temperature and high pressure, and when they become abnormally high temperature and high pressure, the low melting point alloy in the fusible plug melts and Is released to the outside to prevent the equipment from exploding.

Here, the fusible plug will be briefly described.
The fusible plug is made of a metal excellent in heat conduction, for example, brass,
As shown in FIG. 1, the fusible plug main body 1 has a plug shape including an upper portion 2, a wrench engaging portion 3, and a screw portion 4. A communication hole 5 is formed inside the main body, and an upper portion of the communication hole is filled with a low melting point alloy 6. The filling state of the low-melting-point alloy 6 is such that the low-melting-point alloy 6 and the main body 1 are metallically joined, that is, soldered, and are in a completely airtight state.

In this fusible plug, the temperature of the equipment to which the fusible plug is attached does not rise to an abnormally high temperature. Strength decreases. At this time, even if the low-melting alloy is not melted, the low-melting alloy at the joint may peel off due to the internal pressure and may be blown off as a solid. That is, if the filling portion of the low melting point alloy is simply a straight cylindrical shape, the bonding area with the low melting point alloy is small, and the low melting point alloy is easily peeled off by internal pressure. Therefore, an annular groove 7 is formed in the communication hole 5 to increase the bonding area to increase the bonding strength and to make it difficult for the solid low melting point alloy to be peeled off.

In the conventional fusible plug, most of the low melting point alloy to be filled contains Pb or Cd. For example, a low melting point alloy having a melting point of 72 ° C. is 50 Bi-12.5
Cd-25Pb-12.5Sn and melting point of 96
The low melting point alloy at 52 ° C is 52Bi-32Pb-16In and the low melting point alloy at 183 ° C is 37Pb-6.
It was 3Sn.

[0006]

The fusible plug is discarded when a refrigerator or the like to which the fusible plug is attached is broken. For example, it is separated and collected into aluminum, copper, copper alloy, iron and the like. The fusible plug is a copper alloy made of brass, so we want to recover it as a copper alloy and recycle it.However, because the low melting point alloy is filled inside, the fusible plug is used together with other recycled materials. When melted, components other than the brass components Cu and Zn are mixed into the copper alloy as impurities. Therefore, the fusible plug is not recycled and is disposed.

Generally, waste disposal is incineration disposal and landfill disposal. However, fusible plugs are landfill disposal because they are not combustion products. However, in recent years, due to the heavy use of fossil fuels such as gasoline and heavy oil, a large amount of sulfur oxides has been released into the atmosphere, and the rain falling on the earth passes through the atmosphere rich in sulfur oxides. It is so-called "acid rain" that contains sulfur. When this acid rain gets wet on the fusible plugs landfilled in the ground, Pb and C are removed from the low melting point alloy of the fusible plugs.
The harmful metal such as d is melted out, and the water containing the harmful metal becomes groundwater and pollutes the groundwater. When drinking groundwater contaminated with Pb or Cd for many months, there is a concern that these will accumulate in the body and become lead poisoning or cadmium poisoning.

[0008]

The inventor of the present invention has found that by appropriately combining non-toxic Sn, Bi, In, Zn, and Ga, the melting point of 90 to 200 ° C. required for a fusible plug can be obtained. The present invention has been completed.

The present invention relates to a fusible plug in which a low melting point alloy filled in a plug is melted at the time of abnormally high temperature and high pressure in a pressure vessel or a refrigeration cycle pipe to release pressure. The fusible plug is an alloy made of two or more metals selected from Bi, In, Zn, and Ga.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The eutectic temperature of Sn, Bi and In is 5
9 ° C., and a desired operating temperature can be obtained between 59 ° C. and 120 ° C. by appropriately combining these compounding ratios. The eutectic temperature of Bi and In is 72 ° C.
The desired temperature can be obtained in between. And Sn, Z
The eutectic temperature of n and Bi is 130 ° C., and a desired operating temperature can be obtained between 130 and 200 ° C. by setting them to an appropriate mixing ratio. In addition, G
By adding a, the range of selection of the melting point can be widened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The In-
34 Bi alloy was filled. The total length of the fusible plug is 45
mm, the outer diameter of the upper part 2 is 20 mm, the distance between the parallel parts of the wrench joint part 3 is 24 mm, the screw part 4 is R1 / 2 of a tapered screw,
5 has an inner diameter of 14 mm.

An operation test was performed on the fusible plug having the above structure. In the operation test, a fusible plug is attached to the pipe, and the inside of the pipe is filled with compressed air of 1 MPa. This pipe is placed in water, the water is heated at 1 ° C./min by an electric heater, and the temperature at which the fusible plug is activated is read. When the operation test of five fusible stoppers was performed, the operation temperature was 73-
The temperature was between 75 ° C., and very little variation was obtained.

[0013]

As described above, the fusible plug of the present invention is a low melting point alloy which has been considered as an essential component in the prior art.
Since the desired operating temperature can be obtained even though b and Cd are not contained at all, when the refrigerator or the like reaches the above temperature and pressure, it always operates early to discharge the internal refrigerant to the outside, It has an excellent safety effect that prevents the destruction of equipment and does not cause a major accident, and since it contains no Pb or Cd, the refrigerator etc. breaks down and the fusible plug is buried. It is also excellent in safety that it does not pollute groundwater even when disposed.

[Brief description of the drawings]

FIG. 1 is a central half sectional view of a fusible plug.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Upper part 3 Wrench joint part 4 Screw part 5 Communication hole 6 Low melting point alloy 7 Annular groove

Claims (1)

[Claims] 1. A fusible plug in which a low melting point alloy filled in a plug melts at an abnormally high temperature and high pressure in a pressure vessel or a refrigeration cycle pipe to release pressure, wherein the low melting point alloy filled in the plug is Sn, Bi, A fusible plug characterized by being an alloy made of two or more metals selected from In, Zn, and Ga.