JP2011202722A - Three-way valve for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-way valve free from a leakage of a refrigerant from a clearance between a valve stem and a valve stem receiving part even if an O-ring is contracted by a low-temperature refrigerant.SOLUTION: The three-way valve includes: the valve stem 15 mounted with the O-ring 21 and having a thread part 15a; the valve stem receiving part 16 having an internal thread part 16a to which the thread part 15a is screwed; an indoor piping side port 12; an outdoor piping side port 13; a service port 14 mounted with a valve core 19; and a brazed piping part 13a. Special grease 23 is applied to the thread part 15a and the internal thread part 16a. Consequently, even if the surface roughness of a cylinder part of a body 11 of the three-way valve 10 is worsened by acid treatment for piping brazing flux elimination for the brazed piping part 13a, a leakage of the refrigerant from the clearance between the valve stem 15 and the valve stem receiving part 16 is prevented by applying the special grease 23 with sufficient low-temperature fluidity to the thread part 15a and the internal thread part 16a. There is therefore no leakage of the refrigerant to the outside even if the O-ring 21 is contracted by the low-temperature refrigerant.

Description

  The present invention mainly relates to a three-way valve of an air conditioner interposed in a refrigerant piping system of a refrigerator or an air conditioner, and in particular, has a seal structure with a valve body passage by an opening / closing operation position by a valve rod. It is about improvement.

  Conventionally, a refrigerant circuit of an air conditioner is formed by connecting an indoor unit and an outdoor unit through a refrigerant pipe. The refrigerant circuit of the air conditioner includes an air conditioner three-way valve (hereinafter simply referred to as a “three-way valve”) having a service port for air purge and refrigerant filling of the indoor side after pipe connection at the time of installation. Yes. By removing the valve cap of the three-way valve and opening and closing the valve rod, the operation of communicating or closing the refrigerant between the indoor and outdoor is performed.

  In order to prevent refrigerant leakage from the valve stem when the valve cap is removed, there has been proposed a three-way valve provided with a plurality of O-rings to prevent refrigerant leakage (see, for example, Patent Document 1).

JP-A-8-297067

  However, in the conventional three-way valve configuration, since a plurality of O-rings are attached to the valve stem, there is a problem that the size of the three-way valve main body increases and the pipe cover size of the outdoor unit increases.

  Also, the three-way valve is made of brass, and when brazing the refrigeration cycle components in the outdoor unit and the connecting copper piping, a flux agent is used, so it is necessary to perform acid treatment after brazing. However, the inner surface processing accuracy of the three-way valve is deteriorated, and there is a problem that a slight gap is generated between a plurality of O-rings attached to the valve stem to cause refrigerant leakage.

  An object of the present invention is to solve such a conventional problem and to provide a three-way valve of an air conditioner in which refrigerant does not leak to the outside even when an O-ring is contracted by a low-temperature refrigerant.

  In order to solve the above-described conventional problems, the three-way valve of the air conditioner of the present invention includes a valve stem having an O-ring and a screw portion, and a female screw portion to which a screw portion of the valve stem is screwed. A valve rod receiving portion having an inner / outer connection piping portion, a service port fitted with a valve core, and a brazing piping portion, and a special grease is applied to the screw portion and the female screw portion. Even if the surface roughness of the cylinder part of the three-way valve is deteriorated due to acid treatment for removing the pipe brazing flux, special grease with good low-temperature fluidity should be applied to the screw part and female thread part of the valve stem. Thus, since the refrigerant does not leak from the gap between the valve stem and the valve stem receiving portion, even if the O-ring is contracted by the refrigerant, it is possible to prevent the refrigerant from leaking to the outside when the cap is removed.

The three-way valve of the air conditioner of the present invention has a low-temperature flow in the screw portion and the female screw portion even if the surface roughness of the three-way valve main body cylinder portion is deteriorated by acid treatment for removing the brazing flux in the brazing portion. By applying good special grease, the refrigerant will not leak from the gap between the valve stem and the valve stem receiving part.
Even if the O-ring shrinks due to the refrigerant, it is possible to prevent the refrigerant from leaking outside when the cap is removed.

Refrigeration cycle diagram using the three-way valve of the air conditioner in the first embodiment of the present invention (A) Cross-sectional view of the three-way valve, (b) Side view of the valve stem of the three-way valve

  A first invention includes a valve stem having an O-ring and a threaded portion, a valve stem receiving portion having a female threaded portion to which the threaded portion of the valve stem is screwed, an internal / external connection piping portion, and a valve core A three-way valve by acid treatment for removing the brazing pipe flux on the brazing pipe section, which has a service port equipped with a brazing pipe section and special grease is applied to the thread section and the female thread section. Even if the surface roughness of the main body cylinder part deteriorates, the refrigerant does not leak from the gap between the valve stem and the valve stem receiving part, so even if the O-ring contracts due to the refrigerant, Can be prevented from leaking.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.
(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram using a three-way valve of an air conditioner according to a first embodiment of the present invention, FIG. 2 (a) is a sectional view of the three-way valve, and FIG. 2 (b) is a three-way valve. It is a side view of the valve stem of a valve.

  In FIG. 1, the refrigerant discharged from the compressor 2 of the outdoor unit 1 flows and condenses from the four-way valve 3 to the outdoor unit heat exchanger 4, flows through the expansion valve 5, and passes through the expansion pipe 5 through the connection pipe 7. The refrigerant flowing in the heat exchanger 8 and evaporated in the indoor heat exchanger 8 passes through the connecting pipe 9 and is arranged on the liquid side. The three-way valve 10 (hereinafter referred to as “three-way valve 10”) of the air conditioner in the present embodiment. ) To the compressor 2 from the four-way valve 3.

  Next, the configuration and operation of the three-way valve 10 in the present embodiment will be described with reference to FIG. In the four-side of the main body 11 of the three-way valve 10 in the present embodiment, a valve rod receiving portion equipped with an indoor piping side port 12, an outdoor piping side port 13, a service port 14, and a valve rod 15 made of brass material. 16 is arranged.

  A connecting pipe 9 connected to the indoor heat exchanger 8 is connected to the indoor pipe side port 12 via a flare nut 17, and a copper pipe 18 is used as a flux agent to the brazed pipe portion 13 a of the outdoor pipe side port 13. And is connected to the piping on the outdoor heat exchanger 4 side in the same manner.

  As described above, in the present embodiment, the indoor piping side port 12 and the outdoor piping side port 13 are internal and external connection piping sections.

  A valve core 19 is inserted into the service port 14 and a service port cap 25 is attached. Although normally sealed, the service port 14 is evacuated when the air conditioner is installed. A cap 22 for preventing dust from entering from the outside is screwed onto the end of the valve stem receiving portion 16.

The valve stem 15 is integrally provided with a threaded portion 15 a, a hexagonal wrench insertion hole 15 b, and a groove portion 15 c that interposes the O-ring 21. The threaded portion 15a of the valve stem 15 is threadedly engaged with the female threaded portion 16a of the valve stem receiving portion 16 made of brass, and the hexagonal wrench (not shown) is used to rotate the hexagonal wrench insertion hole 15b. By doing so, the valve stem 15 can be advanced and retracted. The threaded portion 15a of the valve stem 15 is subjected to a thin film treatment with a resin coating having a thickness of about 6 microns.

  Special grease 23 made of grease Sumitec 310 or the like having good low temperature fluidity is applied to the female thread portion 16a of the valve stem receiving portion 16, and the thread portion 15a of the valve stem 15 and the female thread portion 16a of the valve stem receiving portion 16 are applied. Prevents leakage of refrigerant from the gap. Also, special grease 23 is applied to the periphery of the O-ring 21. As a result, the special grease 23 enters the gap between the main body 11 and the O-ring 21 which has shrunk due to the temperature of the refrigerant, and reliably prevents the refrigerant from leaking. be able to.

  As described above, the three-way valve according to the present invention does not leak the refrigerant from the gap between the valve stem and the valve stem receiving portion even when the O-ring is contracted by the low-temperature refrigerant. Applicable to.

DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Compressor 3 Four-way valve 4 Outdoor unit heat exchanger 5 Expansion valve 6 Gas side three-way valve 7 Connection piping 8 Indoor unit heat exchanger 9 Connection piping 10 Three-way valve of air conditioner (three-way valve)
11 Body 12 Indoor piping side port (internal / external connection piping)
13 Outdoor piping side port (internal / external connection piping)
13a Brazed piping portion 14 Service port 15 Valve rod 15a Screw portion 15b Hexagon wrench insertion hole 15c Groove portion 16 Valve rod receiving portion 16a Female thread portion 19 Valve core 21 O-ring 22 Cap 23 Special grease

Claims (1)

A valve stem having an O-ring and a threaded portion; a valve stem receiving portion having a female threaded portion into which the threaded portion of the valve stem is screwed; an internal / external connection piping portion; and a service port equipped with a valve core; A three-way valve comprising: a brazed pipe part, and special grease applied to the thread part and the female thread part.