JPH09273837A - Method for filling container with liquid ammonia - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a generally practicable method to fill with liquid ammonia without needing high-cost equipment by a method wherein gaseous ammonia is fed in a container to be filled having the outside making contact with liquid nitrogen to effect liquefaction. SOLUTION: A container 1 made of a stainless steel for filling with liquid ammonia and a bath 2 made of a stainless steel for cooling the filling container to cool the filling container 1 are prepared. The container 1 is provided with a piping 3 on which a valve 4 is mounted. First, the piping 3 is connected to a vacuum pump and a vacuum in the container 1 is drawn. Secondly, liquid nitrogen 5 is injected in the bath 2 for cooling. After a lapse of a short time starting from first injection of liquid nitrogen, injection of ammonia gas in the container 1 through the piping 3 is started. Ammonia on a market with which a cylinder is filled is used and fed in at a pressure of 1.4 kilo per square centimeter by using a pressure reducing valve 4. A filling work is repeated as a mass of the filling container 1 from which the piping 3 is removed is periodically measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling liquid ammonia into a heat medium container for a heat exchanger, a high-pressure container for corrosion test, or the like.

[0002]

2. Description of the Related Art A heat exchanger that uses latent heat of vaporization when a liquid medium is vaporized is widely used. Freon has been widely used as a medium for this purpose, especially in the field of small heat exchangers such as home air conditioners.
However, since CFC is one of the causative substances that destroy the ozone layer, its production is being restricted and its use is being reviewed. Therefore, recently, the use of ammonia, which has been used for a large-sized refrigerator and the like, has been studied instead of CFC for a medium for a small heat exchanger.

In order for the heat exchanger utilizing the latent heat of vaporization of the medium to function, it is necessary to feed the medium into the heat exchanger circuit and liquefy it at a predetermined site. Generally, this method is performed by pressurizing and liquefying a gas medium using a compressor, or by injecting a previously liquefied medium into a circuit in a liquid state. According to laws and regulations such as the above, in the case of both the former and the latter methods, in order to handle media with a prescribed pressure or higher, equipment certified by a designated organization is required, and the person who also has the necessary qualifications There are various restrictions such as being limited to. Therefore, the types of media that can be used are limited unless the necessary facilities are provided or the person is not a predetermined qualified person.

[0004]

Since the flon has a low condensing pressure, for example, the act of feeding and liquefying the flon into a home air conditioner is not subject to the above regulation. Therefore, when the air conditioner is installed, gas injection can be easily performed, which does not hinder the spread of the air conditioner. On the other hand, since ammonia has a high condensing pressure, liquefaction by pressure at room temperature and removal from the cylinder in a liquid state are all within the applicable range of the law.

Therefore, unless a method for feeding and liquefying ammonia that does not require expensive equipment that complies with relevant laws and can be easily carried out by a person without special qualification is used as a medium. The spread of small heat exchangers is not easy.

Therefore, it is an object of the present invention to provide a method for charging liquid ammonia which is excellent in economic efficiency and can be generally and generally carried out without providing expensive equipment for complying with laws and regulations.

[0007]

That is, the present invention is characterized in that gaseous ammonia is fed into a container to be filled whose whole or a part of the outside is in contact with liquid nitrogen to be liquefied. It is a method for filling liquid ammonia. Further, in the method, the pipe for feeding gaseous ammonia into the container to be filled from the outside has a release port near the uppermost part in the container from the upper part of the filling container to near the bottom part in the container. The present invention also provides a method for filling liquid ammonia into a container, which is characterized in that the container is connected to the above.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Generally, the condensing pressure of a gas decreases as the temperature decreases. With ammonia, the condensation pressure at 30 ° C is about 12 kilometers per square centimeter, but if it is cooled to about -35 ° C, it can be immediately liquefied under normal pressure. Therefore, applying this principle,
By using a method of feeding low-pressure ammonia gas into a container to be filled that has been cooled to a temperature of not higher than 0 ° C., it is possible to refill liquid ammonia very easily.

The method of filling liquid ammonia according to the present invention will be described below with reference to examples. As schematically shown in FIG. 1, a liquid ammonia filling container 1 made of stainless steel,
An experiment was conducted by preparing a stainless steel filling container cooling bath 2 for cooling the filling container 1. The container 1 is provided with a pipe 3 to which a valve 4 is attached.

First, the inside of the container 1 was evacuated by connecting the pipe 3 to a vacuum pump. Next, liquid nitrogen 5 was gently injected into the cooling bath 2. The amount of the liquid nitrogen 5 was set to almost the height of the outer upper surface of the filling container 1, and the amount of liquid nitrogen 5 was added at an appropriate interval to evaporate and decrease. Some time after the first injection of liquid nitrogen, the feeding of ammonia gas into the container 1 was started through the pipe 3. As the ammonia, a commercially available one filled in a cylinder was used and was fed at a pressure of 1.4 kg / cm <2> using a pressure reducing valve 4.

The filling operation was repeated while periodically measuring the mass of the filling container 1 from which the pipe was removed. As a result, 1
A gas feed of time allowed to fill about 600 grams of liquid ammonia.

Another invention of the present invention is shown in FIG. An experiment was conducted using a stainless steel filled container 1 and a stainless steel filled container cooling bath 2 as schematically shown in FIG. A stainless steel pipe is piped from the outer upper part of the container 1 to the inside of the container, and the gas introduced through the outer valve 4 is once guided to the container bottom and then returned to the upper end before the container. It is piped so as to be released into the inside. The cooling bath 2 for cooling the filling container is provided with a liquid nitrogen inlet 6 and a nitrogen gas outlet 7.

Next, the filling of liquid ammonia is performed as shown in FIG.
The procedure was similar to. That is, first, the inside of the container 1 was evacuated using a vacuum pump. Then, the cooling bath 2
Liquid nitrogen 5 was gently injected into. Liquid nitrogen was poured from the nitrogen gas discharge port 7 until the liquid nitrogen leaked out. After that, it was added at appropriate intervals to compensate for the decrease in vaporization.

Some time after the first liquid nitrogen injection,
Feeding of ammonia gas was started through the pipe 3. The feed pressure was 2.7 kg per square centimeter. The piping was removed, and the filling operation was repeated while periodically measuring the mass of the filling container. As a result, the gas introduced from the outside is already liquefied and cooled by the liquid ammonia accumulated in the bottom of the container, and then released into the container, so that the liquefaction efficiency of the gas is increased and the gas is supplied for 40 minutes. Was able to charge about 1200 grams of liquid ammonia. As described above, according to the present method, it is possible to easily fill the liquid ammonia with a gas having a low pressure.

The structure and material of the filling container and piping used in the present invention may be designed and selected based on the ultimate pressure when the filled ammonia is used as a heat exchanger or the like. Although the pipe in the filling container is preferably made of metal from the viewpoint of thermal conductivity, it is desirable to use stainless steel, nickel-based alloy, or the like as the material in consideration of the corrosion resistance to ammonia.

Refrigerant used for cooling the filled container at -35 ° C.
Any material can be used as long as it can be cooled to the following, but liquid helium and liquid hydrogen are not cheap and do not meet the purpose of the present invention. Further, dry ice can produce a sufficiently low temperature environment, but it is not suitable because the adhesion to the container is inferior to that of a liquid refrigerant. The reason why the refrigerant used in the present invention is limited to liquid nitrogen is because such points are taken into consideration.

[0017]

The liquid ammonia filling method of the present invention eliminates the need for expensive compressors, explosion-proof equipment, etc., and has made it possible to use it as a refrigerant that has been available only in business offices with extremely limited facilities. Ammonia can be widely and generally used, and an effect of promoting its use as a refrigerant for a small heat exchanger can be expected.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a liquid ammonia filling method of the present invention.

FIG. 2 is a diagram showing another example of the liquid ammonia filling method of the present invention.

[Explanation of symbols]

 1 Liquid Ammonia Filling Container 2 Filling Container Cooling Bath 3 Piping 4 Valve 5 Liquid Nitrogen 6 Liquid Nitrogen Injection Port 7 Nitrogen Gas Release Port

Claims (2)

[Claims] 1. A method of filling liquid ammonia into a container, characterized in that gaseous ammonia is fed into a container to be filled whose whole or a part of the outside is in contact with liquid nitrogen to be liquefied. 2. The pipe for feeding gaseous ammonia from the outside into the container to be filled has a release port near the top of the container from the top of the container to near the bottom of the container. The method of filling liquid ammonia into a container according to claim 1, wherein the container is piped.