Refrigerant pipe unit for room air-conditioner

Details Refrigerant pipe unit for room air-conditioner Refrigerant pipe unit for room air-conditioner

1999-03-16

2001-03-13

Doerrler, William (Department: 3744)

Refrigeration

With means for charging closed refrigeration producing system

C062S077000, C062S299000, C137S360000, C251S148000

Reexamination Certificate

active

06199396

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a refrigerant pipe unit interconnecting an indoor unit and an outdoor unit of a room air-conditioner for circulation of a refrigerant through the room air-conditioner.
2. Description of the Related Art
Room air-conditioners functioning to keep the temperature of the air in rooms at about 18 to 25° C. throughout the year are widely used.
As diagrammatically shown in
FIG. 18
, the conventional room air-conditioner
200
generally comprises an indoor unit
201
, an outdoor unit
202
, and two refrigerant pipes
203
,
204
interconnecting the indoor and outdoor units
201
,
202
for circulation of a refrigerant through the room air-conditioner. In the outdoor unit
202
, a compressor
205
compresses the vaporous refrigerant to a higher pressure and passes it to an outdoor heat exchanger
206
where the vaporous refrigerant is condensed, giving off heat Q
1
to the atmosphere. The liquid refrigerant is fed through to the refrigerant pipe
203
to an expansion valve
207
in the indoor unit
201
. The expansion valve
201
expands the liquid refrigerant to a lower pressure and passes it to an indoor heat exchanger
208
where the liquid refrigerant is evaporated, absorbing heat Q
2
from the surroundings. Thus, the temperature inside the room goes down. The vaporous refrigerant returns through the refrigerant pipe
204
to the compressor
205
. The foregoing circulation of the refrigerant makes the room air-conditioner
200
serve as a cooling system.
Reversing the refrigerant circulating direction makes the room air-conditioner serve as a heat pump heating system, in which the refrigerant absorbs heat from the atmosphere at the outdoor heat exchanger and subsequently gives off this heat to the inside of the room at the indoor heat exchanger.
As generally known, the refrigerant pipes
203
,
204
are laid through a piping hole
212
formed in a wall
211
of the building. After the piping work completes a clearance between the refrigerant pipes
203
,
204
and the piping hole
212
is closed by a putty or a like sealing material
213
to protect the building against weather.
From the sealing point of view, the piping hole
212
in the building wall
211
is preferably as small as possible. But, a larger piping hole is convenient for the piping work. Heretofore, three diameters (65 mm, 75 mm and 85 mm) have been standardized for the piping hole
212
. These standard piping diameters are selected depending on the capacity or power of a room air-conditioner in which the refrigerant pipes
203
,
204
are used. For example, a 65-mm-diameter piping hole is chosen for home-use room air-conditioners, and an 85-mm-diameter piping hole is chosen for business-use room air-conditioners.
The present inventor has proposed a conventional room air-conditioner disclosed in Japanese Patent Laid-open Publication No. HEI 10-89815, entitled “Heat Exchanger and Method of Replenishing Refrigerant to the Same”. The proposed room air-conditioner includes four valves provided at respective refrigerant inlets and outlets of indoor and outdoor units. When the air-conditioner is to be disassembled for moving or transportation, these four valves are closed, and after that the indoor unit, the refrigerant pipes and the outdoor unit are separated. A great part of the refrigerant is trapped inside the indoor and outdoor units. But, a small part of the refrigerant is emitted to the atmosphere when the refrigerant pipes are detached from the indoor and outdoor units. When the room air-conditioner is re-assembled at a new installation site, the refrigerant pipes are attached to the indoor and outdoor units. While all the valves are kept in the fully closed state, the refrigerant pipes are evacuated, then replenished with the refrigerant. Subsequently, all the valves are opened, thus placing the room air-conditioner in the operable condition.
Because the great part of the refrigerant, which is trapped within the indoor and outdoor units, can be used again, environmental contamination caused by emission of the refrigerant is reduced to the minimum.
However, as a demand for environmental preservation of the earth has increased year by year, emission of the refrigerant from the refrigerant pipes
203
,
204
may also be rendered impermissible even though the emission quantity is small.
In addition, a prolonged use of the room air-conditioner may cause leakage of the refrigerant to the atmosphere, requiring replenishment of the refrigerant. This leakage also causes environmental disruption.
In recent years, a mixture of plural sorts of alternate Freon (a trademark for fluorocarbons) has been used as a refrigerant for room air-conditioners. Use of this type of refrigerant makes the replenishment substantially impossible because identification of leaked constituents is substantially impossible. Accordingly, when leakage of the refrigerant occurs, the alternate Freon mixture left in the room air-conditioner is fully removed, then a new alternate Freon mixture is filled in the room air-conditioner.
Under these circumstances, a technique which is capable of sealing the refrigerant inside the refrigerant pipes is required. The standard piping holes are sized to allow passage of two refrigerant pipes, but they do not allow passage of any conventional valve provided at an end of each refrigerant pipe.
In many cases, the refrigerant pipes are connected by the so-called flared type joining system. In this joining system, an end of a deoxidized copper pipe is inserted in a flare nut, then flared like a bell. The flared pipe end is subsequently forced against a chamfered front end of a nipple by tightly fastening the flared nut to the nipple. Because of the metal-to-metal contact, a joint formed between the refrigerant pipe and the nipple is liable to gradually allow leakage of the refrigerant due to a working error or vibrations. Additionally, since the diameter of the refrigerant pipes specified by Japanese Industrial Standards (JIS) is 8A or 10A (corresponding to a nominal diameter of 8 mm or 10 mm), a screwed pipe fitting is used for joining such small diameter pipes. The screwed pipe fitting is compact but it is insufficient to provide a reliable seal against leakage because the refrigerant can flow along threaded grooves. The screwed pipe fitting is susceptible to cracking at the bottom of the threaded grooves.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a refrigerant pipe unit for a room air-conditioner, which can pass through a standard piping hole in the building wall while a refrigerant is kept sealed inside the refrigerant pipe unit.
According to the present invention, there is provided a refrigerant pipe unit for a room air-conditioner including an indoor unit disposed inside a building and an outdoor unit disposed on the outside of the building, the building including a wall having a piping hole extending therethrough. The refrigerant pipe unit comprises two refrigerant pipes extending through the piping hole and interconnecting the indoor unit and the outdoor unit to form a refrigerant passage for circulation of a refrigerant through the room air-conditioner, and a stop valve attached to at least one of opposite ends of each of the two refrigerant pipes for blocking flow of the refrigerant between the indoor unit and the outdoor unit. A maximum size of the stop valve, which is measured in a radial direction about the central axis of each refrigerant pipe, is designed such that the stop valve attached to the one end of each refrigerant pipe can pass through the piping hole in the building wall while the other refrigerant pipe is present inside the piping hole.
When the room air-conditioner is to be moved to another place, stop valves associated with the indoor and outdoor units and the stop valves of the refrigerant pipe unit are fully closed. With the stop valves thus closed, a portion of the refrigerant is trapped inside the refrigerant pipe unit. Then, the refrigerant pipe unit is d

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