JPH04366375A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent the generation of refrigerant fluid noise attributable to pressure fluctuations by installing a piping system which fixedly reduces its cross sectional area on a horizontal piping between a condenser and an expansion valve in a device where the condenser to connect the expansion valve by crossing the direction of its inlet passage with the gravity direction at right angles. CONSTITUTION:A compressor 1, a condenser 2, a piping 3 whose cross section is fixedly reduced, an expansion valve 4 and an evaporator 5 are connected by way of a piping 6 in the shape of a closed circuit, thereby forming a refrigeration cycle. During air conditioning operation, refrigerant is cooled and condensed at the condenser 2 and turned in high pressure liquid refrigerant therein. However, even when the refrigerant is not completely condensed and flow out from the condenser 2 under both vapor and liquid phase conditions, the piping 3 whose cross section is fixedly reduced, allows the fluid to flow continuously in vapor phase and liquid phase respectively, thereby minimizing pressure fluctuations induced by air foam closing when the refrigerant passes through the piping 3. Then, the refrigerant is forced to flow into the expansion valve 4 laid out on a horizontal level where the inlet passages crosses the direction of gravity at right angles.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with an expansion valve in a refrigerant flow rate control and decompression/expansion mechanism, and more particularly to an air conditioner in which refrigerant flow noise is reduced.

0002

BACKGROUND ART Conventionally, as a refrigerant flow rate control and decompression/expansion mechanism, measures have been taken to reduce the refrigerant flow noise generated from the piping before and after the expansion valve, and to reduce the vibration pressure of the piping and the expansion valve. Publication, Utility Model No. 60-69970
There is a publication.

[0003] In JP-A-57-129371, a fixed orifice is provided on the high-pressure side of the expansion valve so that the refrigerant has a predetermined degree of dryness, and air bubbles in the refrigerant when passing through the original orifice of the expansion valve are removed. The aim is to reduce the noise level by increasing the noise level and making the distribution more uniform.

[0004] Furthermore, in the device described in Japanese Utility Model Application Publication No. 60-69970, a variable orifice is provided between the condenser and the orifice of the expansion valve to change the opening area in response to the refrigerant pressure. This prevents noise after the compressor is started, and during steady operation, the variable orifice does not create resistance to the flow of refrigerant, suppressing loss of compressor power and ensuring comfortable and efficient operation.

[0005]

[Problems to be Solved by the Invention] In the above-mentioned prior art, a fixed or variable orifice is provided on the high pressure side of the expansion valve to give the refrigerant a predetermined degree of dryness. Increasing the bubble content in the refrigerant when it passes through the orifice can conversely increase the number of small bubbles, which can increase the high-frequency noise generated when the small bubbles pass through the expansion valve orifice. This results in the occurrence of sex.

[0006] This high-frequency sound is unpleasant to the ears and poses a problem in terms of improving comfort.Furthermore, the low-frequency refrigerant flow noise has not been improved at all, so it is difficult to identify the source of the refrigerant flow noise. It has not yet been possible to eradicate it from its roots.

[0007] Furthermore, if an orifice is provided that is large enough to change the degree of dryness, the orifice itself may generate other noise due to the flow of refrigerant.

[0008] The piping inside the air conditioner mainly consists of horizontal piping and vertical piping, so there are horizontal flows and vertical flows. When the refrigerant exists in a gas-liquid two-phase state, there is a speed difference between the gas refrigerant and the liquid refrigerant in both vertical upward flow and vertical downward flow. Annular flow dominates the flow pattern. Therefore, when vertical upward flow or vertical downward flow in a gas-liquid two-phase state flows into the throttle section of the expansion valve, blockage occurs at the entrance of the throttle section with a mass of bubbles, causing pressure fluctuations. Furthermore, if this bubble blockage is intermittent, pressure fluctuations occur. Furthermore, if the bubble blockage is intermittent, pressure fluctuations become irregular and intermittent, which causes refrigerant flow noise and vibrations in the piping before and after the expansion valve.

[0009] The present invention is characterized in that vertical flow is a flow accompanied by bubbles, such as a slag flow or froth flow, but when it is turned into a horizontal flow, it is mainly a laminar flow or a wavy flow, which is not accompanied by bubbles. This was made based on the experimental discovery that the refrigerant flow that occurs in the piping before and after the expansion valve is based on the experimental discovery that air bubbles do not form at the expansion valve restrictor. In order to reduce noise and pipe vibration caused by refrigerant flow, the refrigerant flows into the expansion valve as a horizontal flow in a stable flow state, improving gas-liquid separation performance and promoting the coalescence of air bubbles, reducing slag The purpose is to shorten the length of horizontal piping required to transform a flow with bubbles, such as a flow or a froth flow, into a laminar flow or wavy flow, in which the gas and liquid phases are continuous.

0010

[Means for Solving the Problems] In order to achieve the above object, the air conditioner of the present invention is configured by connecting at least a compressor, a condenser, an expansion valve, and an evaporator with piping, and the refrigerant is transferred to the compressor. In an air conditioner, the air is circulated through the condenser, expansion valve, evaporator, and back to the compressor, and the expansion valve is connected to the condenser so that the inlet passage of the expansion valve is perpendicular to the direction of gravity. , is characterized in that at least one pipe having a fixed shape with a reduced cross-sectional area is provided on the horizontal pipe between the condenser and the expansion valve.

[0011]

[Operation] In the air conditioner configured as above,
The inlet passage of the expansion valve and the piping that connects to the inlet passage are installed in the horizontal piping section between the expansion valve and the condenser, which are installed in a direction perpendicular to the direction of gravity, to reduce the cross-sectional area of the piping. By providing piping with a shape that reduces the cross-sectional area, a jet of liquid refrigerant and a jet of gas refrigerant are generated to promote the coalescence of the air bubbles that are present intermittently. Therefore, it is possible to shorten the length of the horizontal piping required to cause the gas phase and the liquid phase to flow into the expansion valve in a continuous flow manner.

As a result, even in a gas-liquid two-phase flow where a gas refrigerant and a liquid refrigerant coexist, in a short horizontal pipe, the flow pattern in which the gas phase and liquid phase are discontinuous changes to laminar flow or wavy flow. It is possible to transition to a flow mode in which the phase and liquid phase are continuous, and the expansion valve throttle part is in a flow state where the gas phase and liquid phase are continuous, mainly laminar flow and wavy flow. Since the gas can flow into the air, pressure fluctuations due to air bubble blockage can be reduced.

[0013] Therefore, it is possible to reduce the refrigerant flow noise and the vibrations of the piping before and after the expansion valve, which are caused by this pressure fluctuation.

[0014]

Embodiments Hereinafter, embodiments of the air conditioner according to the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show an air conditioner according to an embodiment of the present invention, in which the direction of the inlet passage or both the inlet and outlet passages of the expansion valve is piped on a horizontal plane orthogonal to the direction of gravity.

FIG. 1 is a system diagram showing the configuration of an air conditioner and the flow of refrigerant during cooling operation. The air conditioner includes a compressor 1, a condenser 2, a pipe 3 having a fixed shape whose cross-sectional area is reduced, an expansion valve 4, an evaporator 5, and a pipe 6 connecting these devices. The refrigerant in the air conditioner is compressed by a compressor 1 to become a high-temperature, high-pressure refrigerant vapor, and is cooled and condensed by a condenser 2 to become a high-pressure liquid refrigerant. At this time, the refrigerant is not completely condensed and is in a gas-liquid two-phase state in the condenser 2.
When passing through the pipe 3, which has a fixed shape and reduces the cross-sectional area of the pipe even if it flows out from the pipe, the separation of the gas and liquid phases and the coalescence of the bubbles are promoted, and the gas and liquid phases become continuous flows and expand. An inlet passage of the valve 4 flows into an expansion valve 4 arranged on a horizontal plane perpendicular to the direction of gravity. This expansion valve 4
The refrigerant is depressurized and expanded to become a gas-liquid two-phase refrigerant at a temperature sufficiently lower than the indoor air temperature, and evaporates in the evaporator 5 while removing heat equivalent to the latent heat of vaporization from the indoor air, becoming a low-pressure gas. It is sucked into the compressor 1 again. Therefore, by installing the fixed-shaped pipe 3 whose pipe cross-sectional area is reduced on the inlet passage side of the expansion valve 4, the refrigerant can flow, for example, into a slag flow.
Even in a flow mode such as a froth flow where intermittent air bubbles exist, the coalescence of the air bubbles is promoted, and the expansion valve 4 has the following properties:
The gas phase and the liquid phase each flow in as continuous horizontal flows. Furthermore, since the coalescence of bubbles is promoted, it is possible to shorten the length of the horizontal piping, which was conventionally required to form a continuous flow of the gas phase and the liquid phase.

FIG. 2 is a system diagram showing the configuration of an air conditioner for both cooling and heating and the flow of refrigerant during cooling operation. Also,
FIG. 3 is a system diagram showing the configuration of an air conditioner for both cooling and heating and the flow of refrigerant during heating operation. The air conditioner includes a compressor 1, a four-way valve 7, a heat exchanger 8, a pipe 3a having a fixed shape whose cross-sectional area is reduced, and an inlet passage and an outlet passage of an expansion valve, all of which are arranged on a horizontal plane perpendicular to the direction of gravity. It is composed of a disposed expansion valve 4, a fixed-shaped pipe 3b whose cross-sectional area is reduced, a heat exchanger 9, and a pipe 6 that connects these devices. Here, during the cooling operation shown in FIG. 2, the refrigerant is supplied to the compressor 1, the four-way valve 7, the heat exchanger 8 as a condenser, and the fixed-shaped pipe 3a whose pipe cross-sectional area is reduced.
, expansion valve 4, fixed pipe shape 3 with reduced pipe cross-sectional area
b, the heat exchanger 9 as an evaporator, the four-way valve 7, and then the compressor 1 again. During the heating operation shown in FIG. 3, the refrigerant flows into the expansion valve 4 through the fixed-shaped pipe 3b whose cross-sectional area is reduced.

Therefore, on the piping connected to the inlet and outlet passages of the expansion valve 4, both of which are arranged on a horizontal plane perpendicular to the direction of gravity, there is a fixed pipe whose cross-sectional area is reduced. By installing the shaped pipes 3a and 3b, even when the refrigerant has a flow mode such as a slag flow or a froth flow that has intermittent air bubbles, it is possible to prevent air bubbles from forming during both cooling and heating operations. The coalescence is promoted, and the gas phase and liquid phase flow into the expansion valve 4 as continuous horizontal flows. Furthermore, since the coalescence of the bubbles is promoted, the length of the horizontal piping, which was conventionally required to form a continuous flow of the gas phase and the liquid phase, can be shortened.

FIGS. 4 to 17 show examples of pipe shapes for pipes having a fixed shape in which the cross-sectional area of the pipe is reduced.

FIG. 4 shows an embodiment in which a fixed orifice is used as the throttle, and is composed of a pipe 10 and a fixed orifice 11.

FIG. 5 shows an example in which a fixed orifice is used as a throttle, but in consideration of the flow of bubbles, the axis of the orifice and the axis of the piping are not on the same line, and the piping 10 and the fixed orifice are It consists of 12.

FIG. 6 shows an embodiment in which a fixed nozzle is used as the throttle, and is composed of a pipe 10 and a fixed nozzle 13.

FIG. 7 shows an example in which a fixed nozzle is used as the aperture, but in consideration of the flow of air bubbles, the axis of the nozzle and the axis of the piping are not on the same line.
and a fixed nozzle 14.

FIG. 8 shows an embodiment in which a fixed venturi tube is used as the restrictor, and is composed of a pipe 10 and a fixed venturi tube 15.

FIG. 9 shows an embodiment in which a fixed diverging tube is used as the throttle, and is composed of a pipe 10 and a fixed diverging tube 16.

FIG. 10 shows an embodiment in which a fixed tapered tube is used as the throttle, and is composed of a pipe 10 and a fixed tapered tube 17.

FIG. 11 shows an embodiment in which a fixed choke is used as the restrictor, and is composed of a pipe 10 and a fixed choke 18.

FIG. 12 shows an example in which a fixed choke is used as the throttle, but in consideration of the flow of air bubbles, the axis of the choke and the axis of the piping are not on the same line. It consists of a choke 19.

FIGS. 13 and 14 show an embodiment in which a full-width weir is used as the throttle, and is composed of a pipe 10 and a full-width weir 20.

FIG. 15 shows an embodiment in which a triangular weir is used as the throttle, and is composed of a pipe 10 and a triangular weir 21.

FIG. 16 shows an embodiment in which a square weir is used as the diaphragm, and is composed of a pipe 10 and a square weir 22.

FIG. 17 shows an embodiment in which a semicircular weir is used as the throttle, and is composed of a pipe 10 and a semicircular weir 23.

[0033] Therefore, regardless of whether a throttle is used or a weir is used, the refrigerant in a gas-liquid two-phase state containing intermittent air bubbles passes through the refrigerant passage whose pipe cross-sectional area is reduced. At this time, a jet of liquid refrigerant 24 and a jet of gas refrigerant 25 are generated,
Gas refrigerant flowing into the space formed around the jet of liquid refrigerant 24 promotes gas-liquid separation and coalescence of bubble masses.

[0034] By providing the embodiments of piping having the shapes shown in FIGS. 4 to 17 on the horizontal piping between the condenser and the expansion valve inlet, the refrigerant is in a gas-liquid two-phase state at the expansion valve. Even in this case, the gas phase and the liquid phase flow in in a continuous state, so that the refrigerant flow noise can be reduced.

Note that two or more pipe shapes may be used in combination.

[0036]

[Effect of the invention] According to the present invention, in an air conditioner,
By providing piping having a fixed shape that reduces the cross-sectional area of the piping between the condenser and the expansion valve in which at least the inlet passage of the expansion valve and the piping portion connected thereto are arranged in a horizontal plane perpendicular to the direction of gravity. This improves gas-liquid separation and promotes the coalescence of bubble masses, allowing the refrigerant to flow into the expansion valve as a continuous horizontal flow of the gas and liquid phases, thereby preventing blockage at the expansion valve restrictor due to bubble masses. It is possible to prevent instability of the refrigerant flow, such as pressure fluctuations, and to reduce the phenomenon of instability in the refrigerant flow. Therefore, refrigerant flow noise generated due to pressure fluctuations can be reduced, and pipe vibration can also be reduced.

[0037] Furthermore, since the unpleasant refrigerant flow noise can be reduced, comfort is also improved.

Furthermore, it is possible to shorten the length of the horizontal pipe that is required to make the gas phase and liquid phase flow continuously.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a cycle during cooling operation of an air conditioner when pipes having a fixed shape with a reduced pipe cross-sectional area are arranged according to an embodiment of the present invention.

FIG. 2 is a system diagram of a cycle during cooling operation of an air conditioner for both cooling and heating when pipes having a fixed shape with a reduced pipe cross-sectional area are arranged according to an embodiment of the present invention.

FIG. 3 is a system diagram of a heating operation cycle of an air conditioner for both cooling and heating when pipes having a fixed shape with a reduced pipe cross-sectional area are arranged according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram when an orifice is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of an embodiment of the present invention in which an orifice eccentric from the pipe axis is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced;

FIG. 6 is an explanatory diagram when a nozzle is used to throttle a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram when a nozzle eccentric from the pipe axis is used to throttle a pipe having a fixed shape in which the cross-sectional area of the pipe is reduced according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram when a Venturi tube is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram when a divergent tube is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 10 is an explanatory diagram when a tapered pipe is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 11 is an explanatory diagram when a choke is used to throttle a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram when a choke eccentric from the wiring axis is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 13 is an explanatory diagram when a full-width weir is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced according to an embodiment of the present invention.

FIG. 14 is a front view of a pipe according to an embodiment of the present invention when a full-width weir is used to throttle a pipe having a fixed shape whose cross-sectional area is reduced.

FIG. 15 is a front view of a pipe according to an embodiment of the present invention when a triangular weir is used as a throttle for a pipe having a fixed shape whose cross-sectional area is reduced.

FIG. 16 is a front view of a pipe according to an embodiment of the present invention when a square weir is used as a restriction for a pipe having a fixed shape whose cross-sectional area is reduced.

FIG. 17 is a front view of a pipe according to an embodiment of the present invention when a semicircular weir is used to restrict a pipe having a fixed shape whose cross-sectional area is reduced.

[Explanation of symbols]

1... Compressor, 2... Condenser, 3, 3a, 3b... Piping, 4...
Expansion valve, 5... Evaporator, 6, 10... Piping, 7... Four-way valve, 8
, 9... Heat exchanger, 11, 12... Orifice, 13, 14
... Nozzle, 15... Venturi tube, 16... Divergent tube, 1
7...Tapered pipe, 18, 19...Choke, 20...Full width weir, 21...Triangular weir, 22...Square weir, 23...Semicircular weir,
24...Liquid refrigerant, 25...Gas refrigerant.

Claims (1)

[Claims] Claim 1: The refrigerant includes a compressor, a condenser, an expansion valve, an evaporator, and piping connecting these, and the refrigerant is returned from the compressor to the compressor via the condenser, the expansion valve, and the evaporator. In an air conditioner in which the expansion valve is connected to the condenser in such a way that the direction of the inlet passage of the expansion valve is orthogonal to the direction of gravity, the An air conditioner characterized in that at least one pipe has a fixed shape in which the cross-sectional area of the pipe is reduced.