JP2007032979A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device in which an expansion valve suitable for refrigerant flow control, reducing refrigerant flow sound and having proof stress to plugging of foreign matter is installed. <P>SOLUTION: A valve chamber 5 provided with an inflow port 32 formed in a side face, and a valve seat 6 formed at a bottom face, is formed inside an expansion valve body part 3 of the expansion valve 1, and a needle 2 that can advance to and retreat from the valve seat 6 is installed penetrating the top face of the valve chamber 5. A needle tip part 4 gradually reduced in diameter in a flow-out direction is formed at the tip of the needle 2, and the valve seat 6 is formed with an orifice inlet part 7 gradually reduced in diameter in the flow-out direction, an orifice center part 8 of approximately cylindrical shape, and an orifice outlet part 9 gradually enlarged in diameter in the flow-out direction. A clearance passage 47 gradually narrowed in the flow-out direction is thereby formed by the needle tip part 4 and the orifice inlet part 7, and the separation of refrigerant flow is reduced in the start position of the orifice center part 89 to reduce noise. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid refrigeration cycle apparatus, and more particularly to a refrigeration cycle apparatus provided with an expansion valve suitable for reducing refrigerant flow noise.

  In a conventional refrigeration cycle apparatus of an air conditioner, a variable capacity compressor such as an inverter is used in order to cope with a change in air conditioning load. The rotational frequency of the compressor is controlled according to the size of the air conditioning load, and the throttle amount of the expansion valve is adjusted in order to effectively use the evaporator and the condenser in accordance with the rotational speed of the compressor. At this time, the refrigerant flowing into the expansion valve may be a vapor single phase, a liquid single phase, or a gas-liquid two phase. In each case, there is a problem that noise occurs in the expansion valve. In particular, when passing in gas-liquid two-phase, the noise frequency fluctuates, which is harsh.

  In addition, in order to reduce the refrigerant flow noise generated by the expansion valve, as the expansion valve control of the refrigeration cycle device, the superheat degree control of the evaporator outlet, the supercooling degree control of the condenser outlet, the superheat degree control of the compressor suction section And superheat degree control of the compressor discharge section. However, since the gas-liquid two-phase refrigerant flows through the expansion valve portion when the refrigeration cycle apparatus is started up or when the capacity of the compressor is controlled according to fluctuations in the air conditioning load, refrigerant flow noise may occur. In such a case, the expansion valve control may not be possible.

  In order to prevent such noise, for example, an invention is disclosed in which a porous body is installed at each of an inlet (a terminal portion of an inflow pipe) and an outlet (a start end of an outflow pipe) of a valve chamber of an expansion valve. That is, since the flow state of the refrigerant flowing into the expansion valve is a flow accompanied by a bubble soul, when the refrigerant passes through the porous body, it is shifted to a flow state in which the gas phase and the liquid phase are mixed, Since the refrigerant pressure pulsation in the section becomes continuous, refrigerant noise and piping vibration are reduced (see, for example, Patent Document 1).

  Furthermore, for example, an invention is disclosed in which a honeycomb pipe and a cylindrical pipe in which a plurality of small diameter tubes are bundled are alternately arranged in a predetermined range close to the expansion valve of the inflow pipe and a predetermined range close to the expansion valve of the outflow pipe. Yes. That is, a silencer is formed by the honeycomb pipe and the cylindrical pipe, and the refrigerant repeats homogenization and expansion in the process of passing through the silencer, and transmission of generated noise and pressure pulsation during decompression is suppressed (for example, , See Patent Document 2).

JP-A-7-146032 (page 3-4, FIG. 1) JP-A-11-325655 (page 4-6, FIG. 2)

  However, in the invention disclosed in Patent Document 1 or 2, foreign matter is trapped by the porous body or honeycomb pipe in the refrigeration cycle apparatus, which may cause clogging of the foreign matter. There was a problem that the heating performance could not be realized.

  The present invention has been made to solve the above problems, and is suitable for refrigerant flow control, reduces refrigerant flow noise, and has a refrigeration cycle having an expansion valve that is resistant to foreign matter clogging in the refrigeration cycle apparatus. The object is to obtain a device.

A refrigeration cycle apparatus according to the present invention includes a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant condensed by the condenser, and the expansion valve. An evaporator that evaporates the refrigerant expanded by the pipe, and a pipe that sequentially connects the compressor, the condenser, the expansion valve, and the evaporator,
The expansion valve includes a valve chamber having a fluid inlet formed on a side surface and a fluid outlet formed on a bottom surface, and is movable forward and backward through the top surface of the valve chamber toward the outlet. An orifice inlet portion that gradually decreases in diameter toward the outflow direction at the outflow port, and a substantially cylindrical orifice central portion on the outflow side of the orifice inlet portion, the tip of the needle A needle tip portion that gradually decreases in diameter in the outflow direction is formed, and a gap channel that gradually narrows in the outflow direction is formed by the orifice inlet portion and the needle tip portion. And

  As described above, according to the present invention, a “tapered gap flow path” that gradually narrows in the outflow direction is formed in the expansion valve by the needle tip and the orifice inlet. In addition to preventing noise generation and reducing noise, even if there is a foreign object in the refrigeration cycle apparatus in which such a pressure reducing valve is installed, there is no risk of foreign object clogging, and the original cooling and heating performance is realized. The effect of being able to be obtained. Moreover, since it is not necessary to provide a porous body such as a honeycomb pipe in the flow path, the manufacturing cost and the maintenance cost are reduced.

[Embodiment 1]
(Electric expansion valve)
1 and 2 are a configuration diagram and a sectional configuration diagram showing an example of an expansion valve installed in the refrigeration cycle apparatus according to Embodiment 1 of the present invention. 1 and 2, an electric expansion valve 1 (hereinafter referred to as “expansion valve 1”) includes a needle 2 and an expansion valve body 3, and a valve chamber 5 is formed inside the expansion valve body 3. .

(needle)
A needle through hole 31 is formed in the top surface of the expansion valve body 3 (same as the top surface of the valve chamber 5), and the needle 2 is inserted into the needle through hole 31 in a fluid-tight manner so as to be slidable. Further, a stepping motor 10 is installed on the upper portion of the expansion valve main body 3, and the rotation angle of the stepping motor 10 is converted into a translation distance by a rotation / translation conversion mechanism (not shown) and used for the raising / lowering operation of the needle 2. Note that the tip of the needle 2 is reduced in diameter to form a needle tip 4 (the same as the range ABC in the figure). The shape of the needle tip 4 is not limited, and may be configured with, for example, a one-step taper that is a linear taper or a multi-step taper whose angle changes in multiple steps.

(valve seat)
A valve seat 6 constituting an outlet is formed on the bottom surface of the valve chamber 5. The valve seat 6 has an orifice inlet portion 7 (same as the range DE in the drawing) that gradually decreases in diameter in the outflow direction (downward in the figure), and substantially on the outflow side of the orifice inlet portion 7. A cylindrical orifice central portion 8 (same as the range EF in the figure) and an orifice outlet portion 9 (F- in the figure) that gradually increases in diameter toward the outflow direction toward the outflow side of the orifice central portion 8. The same as the range of G).
At this time, the length of the orifice inlet portion 7 (same as the vertical distance between the start position D and the end position E) and the length of the orifice outlet portion 9 (same as the vertical distance between the start position F and the end position G) Are 5 times the diameter of the orifice inlet 7. The shapes of the orifice inlet portion 7 and the orifice outlet portion 9 are not limited. For example, the orifice inlet portion 7 and the orifice outlet portion 9 may be configured with a single-stage taper that is a linear taper or a multi-stage taper whose angle changes in multiple stages.

(Gap channel)
The needle tip 4 of the needle 2 enters the orifice inlet 7 to form a gap channel 47. At this time, the angle α formed between the needle tip 4 and the orifice inlet 7 is 60 °. That is, a line connecting the final end position A forming the needle 2 (corresponding to the intersection with the needle tip 4 at the end of the parallel part of the needle 2) and the tip position C of the needle tip 4; The angle formed by the line connecting the start position D of the orifice inlet portion 7 and the end position E of the orifice inlet portion 7 (same as the start position of the orifice central portion 8) is 60 °.
The orifice outlet portion 9 is tapered, and the taper angle β is 60 °. That is, the angle formed by the line connecting the start position F and the end position G of the orifice outlet 9 and the line connecting the start position F and the end position G at the diagonal positions is 60 °.

(Inflow pipe, outflow pipe)
A refrigerant inlet 32 is formed on the side surface of the expansion valve main body 3 (same as the side surface of the valve chamber 5), and a connecting pipe 20 (hereinafter referred to as “inflow pipe 20”) is horizontally installed in the inlet 32. Yes.
An outflow pipe installation groove 33 is formed on the bottom surface of the expansion valve body 3 (same as the bottom surface of the valve chamber 5) so as to surround the orifice outlet portion 9, and the connection pipe 30 (hereinafter “ An outflow pipe 30 ").
The inflow pipe 20 and the outflow pipe 30 are copper pipes and are welded to the expansion valve main body 3 made of brass, but the material forming the members is not limited.
Therefore, the refrigerant (not shown) flows into the valve chamber 5 via the inflow pipe 20, and the gap flow path 47 formed by the needle tip portion 4 and the orifice inlet portion 7 and the cylindrical orifice central portion 8. And then flows out into the outflow pipe 30 through the tapered orifice outlet 9.

(Refrigeration cycle equipment)
FIG. 3 is a refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus according to Embodiment 1 of the present invention. In FIG. 3, the refrigeration cycle apparatus 100 includes a compressor 21, a condenser 22, an expansion valve 1 that is a throttling mechanism, an evaporator 23, a pipe 24 that is sequentially connected, and a pipe 25 (to the inflow pipe 20). 2), a pipe 26 (corresponding to the outflow pipe 30), and a pipe 27. The mass flow rate of the refrigerant is about 20 kg / h to 200 kg / h.

FIG. 4 is a conceptual diagram of a Ph diagram of the refrigeration cycle apparatus shown in FIG. The positions “I, B, C, and D” in FIG. 4 correspond to the positions “I, B, C, and D” of the refrigeration cycle apparatus shown in FIG.
That is, in the expansion valve 1, the refrigerant is decompressed in an isenthalpy (isoentropic) manner. Note that R410A is used as the refrigerant, and refrigeration oil that does not easily dissolve the refrigerant is used.

(Refrigerant flow)
FIG. 5 is a partial schematic diagram illustrating the state of the refrigerant flowing into the expansion valve installed in the refrigeration cycle apparatus according to Embodiment 1 of the present invention, where (a) is the present invention, and (b) is a comparative example. It is a conventional expansion valve for.
In FIG. 5A, in the normal cooling operation, by driving the stepping motor 10 of the expansion valve 1 that is a throttle device, the needle tip 4 of the needle 2 is inserted into the orifice inlet 7 and the gap channel 47 is formed. It is formed. That is, by controlling the stepping motor 10, the gap area is adjusted and the flow rate of the refrigerant is adjusted.
For example, in the configuration of the needle tip portion 4 and the orifice inlet portion 7 having a predetermined shape, the clearance area is adjusted so that the mass velocity of the refrigerant passing through the needle tip portion 4 and the orifice inlet portion 7 is 400 kg / m ² s to 10,000 kg / m ³ s.

At this time, the compressor 21 is operated at the number of rotations corresponding to the air conditioning load, and the refrigerant that has become high-temperature and high-pressure vapor refrigerant in the compressor 21 (same as in state b) is the condenser 22 (same as in the outdoor heat exchanger). Is condensed and liquefied (same as in state c), and further decompressed at expansion valve 1 to become a low-pressure two-phase refrigerant (same as in state d). The low-pressure two-phase refrigerant flows into the evaporator 23 and evaporates (same as in the state a), returns to the compressor 21 and becomes vapor refrigerant again.
At this time, the expansion valve 12 determines the positional relationship between the orifice inlet portion 7 and the needle tip portion 4 so that the outlet state of the condenser 22 is constant according to the air conditioning load, for example, the degree of supercooling is 5 °. It is controlled. Therefore, even when the air conditioning load fluctuates sharply and the refrigerant state at the inlet of the expansion valve 1 shifts to the gas-liquid two-phase state, the generation of refrigerant flow noise can be suppressed while the control is continued. (This will be described in detail separately below.)

Therefore, the refrigeration cycle apparatus can always be operated in a highly efficient state. In other words, when the conventional expansion valve is used, the refrigerant state becomes unstable at the inlet of the expansion valve at the time of excessive operation or the like, so it is necessary to perform full opening control for a certain period of time, and the refrigeration cycle apparatus is always highly efficient. However, in the present invention, the refrigeration cycle apparatus can always be controlled with high efficiency.
The control of the expansion valve 1 is not limited to adjusting the outlet state of the condenser 22 (corresponding to the state C), but the refrigerant state (corresponding to the state A) of the evaporator 23 and the compressor. The same effect can be obtained even if it is determined by the refrigerant state of the suction 21 (same as in the state A) and the refrigerant state of discharge from the compressor 21 (same as in the state b).

In FIG. 5A, the gas-liquid two-phase refrigerant flows into the valve chamber 5 from the inflow pipe 20 installed horizontally. Then, it flows into the gap flow path 47 constituted by the needle tip portion 4 and the orifice inlet portion 7, and subdivides the vapor slag while reducing the pressure, and the liquid refrigerant and the vapor refrigerant are mixed. Then, the refrigerant in the mixed state flows more smoothly than before, and flows into the main throttle portion composed of the orifice central portion 8 (the same as the smallest gap portion), so that the separation flow at the orifice central portion 8 is suppressed. There is an effect to. Therefore, discontinuous pressure fluctuations do not occur and noise is reduced.
That is, the flow separation at the start position E of the orifice central portion 8 is less likely to occur. Since noise is considered to be caused by fluctuations in the development and disappearance of this separation flow and the separation flow itself, it is preferable to suppress separation as much as possible as a noise reduction measure, and the present invention suppresses this separation. ing.
Further, the orifice outlet 9 rectifies the gas-liquid two-phase jet flowing out from the constricted portion formed by the orifice central portion 8 with a taper enlarged to the outflow side, thereby reducing pressure fluctuation due to the jet and reducing noise. It can be reduced.

In FIG. 5B, conventionally, the refrigerant condensed in the condenser flows into the expansion valve. However, the state of the refrigerant fluctuates depending on the use environment conditions or at the time of start-up, and is in a gas-liquid two-phase state or a liquid single-phase state. It has been known and known that noise occurs in the expansion valve due to flow. In particular, when flowing with a gas-liquid two-phase refrigerant in a fluid state in which the gas-liquid two phases are intermittent, such as a slag flow or a plug flow, discontinuous noise is generated in the expansion valve.
That is, in the conventional orifice, since the bottom surface of the valve chamber 50 forms the valve seat 60, the clearance channel 460 is formed by the inner peripheral edge J (same as the start position) of the valve seat 60 and the needle 40. Therefore, flow separation occurs at the start position J at the orifice inlet, and the fluctuation between the development and disappearance of the separation flow, and the separation flow itself is considered to cause noise. At this time, the portion (foaming point) where the liquid refrigerant starts to foam fluctuates in the valve seat 60 (same as the throttle portion and JK) where the separation flow has occurred. Inside the separation flow, a vortex is generated at the orifice inlet portion (near start position J), and this vortex develops with time. The developed vortex can no longer stop at the entrance, and is flowed downstream to release energy. Due to the behavior of a series of vortices, the foaming point varies, so the flow rate of the refrigerant also varies. As a result, pressure fluctuation occurs and noise is generated.

(Orifice shape)
6 and 7 are measurement results showing the relationship between the shape of the expansion valve installed in the refrigeration cycle apparatus according to Embodiment 1 of the present invention and the noise level.
In FIG. 6, the angle α formed between the needle tip 4 and the orifice inlet 7 is referred to as a “taper angle” for convenience, and the relationship between the taper angle and the noise level difference is defined with the noise level at a taper angle of 30 ° as 0. Is shown. This noise level is a result of measuring noise by providing a taper at the orifice inlet 7 of the expansion valve 1 and flowing a gas-liquid two-phase fluid. It can be seen that the noise level is reduced when the taper angle is 60 ° or less.

  In FIG. 7, the relationship between the length of the orifice inlet portion 7 normalized by the inner diameter d of the orifice central portion 8 and the noise level difference of the expansion valve 1 is shown. The length of the orifice inlet portion 7 is defined by the distance between the start position D and the end position E of the orifice inlet portion 7 in the vertical direction (same in the vertical direction in the figure). The noise level difference represents the noise level with respect to each length, with the noise level of the length 5d of the orifice inlet 7 being 0. The noise level is the lowest at the length 5d of the orifice inlet 7.

(Other embodiments)
As described above, the refrigerant flows into the valve chamber 5 through the inflow pipe 20, and the gap channel 47 formed by the needle tip portion 4 and the orifice inlet portion 7, the orifice central portion 8, and the tapered orifice. Although what passes through the exit part 9 and flows out into the outflow pipe 30 is shown, the present invention is not limited to this, and the refrigerant may flow in the opposite direction.
That is, when refrigerant flows into the valve chamber 5 from the bottom surface of the expansion valve 1 and flows out from the side surface, or in a refrigeration cycle apparatus in which cooling operation and heating operation are switched by a four-way valve, the slag flow or plug flow is intermittent. Similarly, when the gas-liquid two-phase refrigerant flows into the orifice outlet portion 9, the vapor refrigerant is subdivided and mixed with the liquid refrigerant and simultaneously rectified by the outlet side taper of the orifice outlet portion 9. And since it flows into the orifice inlet part 7 via the orifice center part 8, it is effective in a pressure fluctuation being suppressed and noise being reduced.

The block diagram which shows an example of the expansion valve installed in the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The cross-sectional block diagram which shows an example of the expansion valve installed in the refrigeration cycle apparatus which concerns on Embodiment 1 of this invention. The refrigerant circuit figure which shows an example of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. The conceptual diagram of the Ph diagram of the refrigerating-cycle apparatus shown in FIG. The partial schematic diagram explaining the state of the refrigerant | coolant which flows in into the expansion valve shown in FIG. The measurement result which shows the relationship between the shape of the expansion valve shown in FIG. 2, and a noise level. The measurement result which shows the relationship between the shape of the expansion valve shown in FIG. 2, and a noise level.

Explanation of symbols

1: electric expansion valve, 2: needle, 3: expansion valve body, 4: needle tip, 5: valve chamber, 6: valve seat, 7: orifice inlet, 8: orifice central, 9: orifice outlet 10: stepping motor, 20: inflow pipe, 21: compressor, 22: condenser (outdoor heat exchanger), 23: evaporator, 24: pipe, 25: pipe, 26: pipe, 27: pipe, 30: Outflow pipe, 31: Needle through hole, 32: Inlet, 33: Outlet pipe installation groove, 47: Clearance channel, α: Angle formed by needle tip and orifice inlet angle, β: Taper angle of orifice outlet A: final end position (needle), C: tip position (needle), D: start position (orifice inlet section), E: end position (orifice inlet section), F: start position (orifice outlet section), G : End position (orifice outlet), d: Inner diameter (orifice center).

Claims (7)

A compressor that compresses the refrigerant; a condenser that condenses the refrigerant compressed by the compressor; an expansion valve that expands the refrigerant condensed by the condenser; and an evaporation that evaporates the refrigerant expanded by the expansion valve A refrigeration cycle apparatus having a condenser, and a pipe for sequentially connecting the compressor, the condenser, the expansion valve, and the evaporator,
The expansion valve includes a valve chamber having a fluid inlet formed on a side surface and a fluid outlet formed on a bottom surface, and is movable forward and backward through the top surface of the valve chamber toward the outlet. An orifice inlet portion that gradually decreases in diameter toward the outflow direction at the outflow port, and a substantially cylindrical orifice central portion on the outflow side of the orifice inlet portion, the tip of the needle A needle tip portion that gradually decreases in diameter in the outflow direction is formed, and a gap channel that gradually narrows in the outflow direction is formed by the orifice inlet portion and the needle tip portion. A refrigeration cycle device. A compressor that compresses the refrigerant; a condenser that condenses the refrigerant compressed by the compressor; an expansion valve that expands the refrigerant condensed by the condenser; and an evaporation that evaporates the refrigerant expanded by the expansion valve A refrigeration cycle apparatus having a condenser, and a pipe for sequentially connecting the compressor, the condenser, the expansion valve, and the evaporator,
The expansion valve includes a valve chamber having a fluid inlet formed on a side surface and a fluid outlet formed on a bottom surface, and is movable forward and backward through the top surface of the valve chamber toward the outlet. An orifice inlet portion that gradually decreases in diameter toward the outflow direction, a substantially cylindrical orifice central portion on the outflow side of the orifice inlet portion, and an outflow of the orifice central portion. An orifice outlet portion that gradually increases in diameter toward the outflow direction is formed on the side, and a needle tip portion that gradually decreases in diameter toward the outflow direction is formed at the tip of the needle. A refrigeration cycle apparatus characterized in that a gap flow path that gradually narrows in the outflow direction is formed by the needle tip.   The refrigeration cycle apparatus according to claim 1 or 2, wherein an angle formed by the inner surface of the orifice inlet of the expansion valve and the outer surface of the needle tip is 60 ° or less.   The refrigeration cycle apparatus according to claim 2 or 3, wherein the taper angle of the orifice outlet of the expansion valve is 60 ° or less.   5. The refrigeration cycle apparatus according to claim 1, wherein a length of an orifice inlet portion of the expansion valve is not less than five times a diameter of a central portion of the orifice.   6. The refrigeration cycle apparatus according to claim 2, wherein a length of an orifice outlet portion of the expansion valve is not less than 5 times a diameter of a central portion of the orifice. The expansion valve is provided with needle advancement / retraction means for advancing / retreating the needle and allowing the needle tip portion to enter the orifice inlet portion,
The refrigeration cycle apparatus according to any one of claims 1 to 6, further comprising control means for controlling the rotational speed of the compressor and the advance / retreat amount of the needle in accordance with a cooling load.

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