JPH07280393A - Flow control valve and refrigerating cycle apparatus using the same - Google Patents

Abstract

PURPOSE:To provide a flow control valve having stable valve switching characteristics (hysteresis) even in an environment in which fluid is easily varied in a gas-liquid phase state. CONSTITUTION:A first orifice 26 is formed in a case body 12, an intermediate pressure chamber 30 is formed at its downstream side, and a seat 16 in which a ball 14 is seated is provided further at its downstream side. The chamber 30 which becomes an intermediate pressure PM between its upstream side pressure PH and a downstream side pressure PL at the time of opening a ball valve is provided so that pressure of the chamber 30 is lowered from the pressure PH of the upstream side. Thus, a change of a differential pressure DELTAP necessary to close the vale when a phase state of the refrigerant is varied from a liquid phase to a gas phase at the upstream and downstream sides can be reduced as much as possible. In this manner, since a valve switching pressure is scarcely affected by influence of the state of the refrigerant, i.e., dryness, the valve switching operation is stabilized. A water hammer sound which is easily generated at the time of stopping a refrigerant flow to be circulated in a refrigerating cycle can be effectively reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve for opening and closing a fluid passage, and more particularly to a flow control valve for controlling the flow rate of a refrigerant passage in a refrigeration cycle.

[0002]

2. Description of the Related Art As a pressure check valve provided in a fluid passage, as disclosed in Japanese Utility Model Publication No. 51-16027 filed by the applicant of the present application for utility model registration, the pressure check valve at the downstream side of the pressure at the upstream side is It is known to prevent fluid from flowing back through the fluid passages when the pressure increases. This pressure check valve uses the magnetic force and tension of the valve element itself to prevent the back flow of the fluid in the fluid flow path. It has a long life, stable performance, low cost and small size. There is.

[0003]

In addition, the applicant of the present patent application, in the specification of the above-mentioned patent application (Japanese Patent Application No. 5-220029), discloses a flow control valve provided in a refrigerant circuit constituting a refrigeration cycle. The following flow control valves are proposed. The flow rate control valve opens when the pressure difference between the upstream side pressure and the downstream side pressure becomes equal to or less than a predetermined value (for example, 0.2 MPa), and the pressure difference becomes equal to or more than the predetermined value (for example, 0.25 MP). It is configured to close the valve when.

The structure of the flow rate control valve comprises a ball housed in the case body and a biasing means for biasing the ball. The flow control valve is throttled by a minute clearance between the ball and the case body in order from the upstream side of the flow. A fixed restrictor such as an orifice or nozzle is located. Then, when the valve is closed, an intermediate pressure is generated immediately downstream of the ball, so that an opening / closing pressure difference is provided between the opening pressure and the closing pressure of the opening / closing valve so that the opening / closing valve has hysteresis. ing.

However, since the phase of the refrigerant circulating in the refrigeration cycle changes due to heat dissipation and heat absorption, the state of the refrigerant varies depending on the ambient temperature and pressure of the refrigerant, and the state of the gas phase is
It changes to a liquid phase or a gas-liquid two-phase state, and when it is a gas-liquid two-phase state, the phase state ratio between the gas phase and the liquid phase changes. Therefore, according to the valve structure that constitutes such a ball valve,
Since the pressure difference between the pressure on the upstream side of the ball and the pressure on the downstream side of the ball, that is, the effective area of the pressure difference applied to the ball greatly increases or decreases depending on the phase state of liquid phase or vapor phase (ratio of liquid phase to vapor phase). With a simple ball valve structure used in an environment in which the phase state of the surrounding fluid changes, it is difficult to provide stable hysteresis of the opening / closing valve characteristics.

The present invention relates to a gas phase of a fluid flowing through a fluid passage,
Less susceptible to changes in liquid phase or gas-liquid two-phase state,
An object of the present invention is to provide a flow control valve having stable hysteresis in valve opening characteristics and valve closing characteristics. Another object of the present invention is to provide a flow rate control valve with a fast on-off valve operation. A further object of the present invention is to provide a flow control valve capable of reducing the water hammer noise that tends to occur when the flow of the refrigerant circulating in the refrigeration cycle is stopped.

[0007]

A flow control valve according to the present invention for solving the above-mentioned problems has a passage opening area smaller than a passage opening area of a standard passage formed inside a case body. A first throttle portion, and a second throttle portion having a passage opening area smaller than a passage opening area of a standard passage formed inside the case body and provided downstream of the first throttle portion with respect to a fluid flow. And an intermediate pressure chamber formed inside the case body between the first throttle portion and the second throttle portion. The second throttle section is a variable throttle that operates by a pressure difference between the intermediate pressure of the intermediate pressure chamber and the pressure on the downstream side of the second throttle section.

According to a second aspect of the flow control valve, the first throttle portion of the first aspect is a fixed throttle having a fixed passage opening area. In the flow control valve according to claim 3, the second throttle portion according to claim 1 is
It is a valve means for closing the valve when the differential pressure between the intermediate pressure of the intermediate pressure chamber and the pressure on the downstream side of the second throttle portion is relatively large, and opening the valve when it is small.

According to a fourth aspect of the present invention, in the flow control valve according to the first aspect of the present invention, the second flow control valve is provided for the fluid flow.
A third throttle portion is provided on the downstream side of the throttle portion. The flow control valve according to a fifth aspect is characterized in that a gas reservoir is provided on a side surface of the intermediate pressure chamber of the flow control valve according to the fourth aspect. The refrigeration cycle apparatus described in claim 6 is a refrigerant circuit that constitutes a refrigeration cycle.
It is characterized in that any one of the flow control valves of 5 is used.

In the refrigeration cycle apparatus described in claim 7, the flow control valve according to any one of claims 1 to 5 is used between the liquid receiver and the pressure reducing device provided in the refrigerant circuit which constitutes the refrigeration cycle. Is characterized by.

[0011]

In general, the opening / closing pressure of the differential pressure valve changes depending on the state of the fluid flowing from the upstream side of the valve to the downstream side of the valve. For example, the valve upstream side / downstream side differential pressure ΔP required for the valve opening / closing operation greatly changes depending on whether the refrigerant is in a gas state, a gas-liquid two-phase state, a liquid state, or a supercooling state. An example of this is shown in FIG. As shown in FIG. 4, the differential pressure ΔP required for closing the valve greatly changes depending on the degree of dryness (phase state) of the refrigerant, so that when the state of the refrigerant changes, the opening / closing operation of the differential pressure valve becomes unstable.

According to the flow control valve of the present invention, by providing an intermediate pressure chamber having an intermediate pressure between the upstream side of the valve and the downstream side of the valve, the valve is closed when the phase state of the refrigerant changes. It is possible to minimize the change in the differential pressure ΔP required for the above. As a result, the valve open set pressure and the valve closed set pressure are less likely to be affected by the state of the refrigerant, that is, the degree of dryness, so that the opening / closing operation of the valve is stabilized.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) A first embodiment of the present invention is shown in FIGS. As shown in FIG. 5, the refrigerant circuit 20 constituting the refrigeration cycle of the first embodiment has a compressor 1, a condenser 2, a liquid receiver 3, a flow control valve 10, an expansion valve 4, and an evaporator 5 in this order. It is connected by a pipe 9.

The specific structure of the flow control valve 10 is shown in FIGS. 1 and 2. Figure 1 shows the state when the valve is closed,
FIG. 2 shows the state when the valve is open. As shown in FIG. 1 and FIG. 2, in the flow control valve 10, a large diameter passage 12 a is formed on the upstream side inside the case body 12, and a small diameter passage 12 is formed on the downstream side.
b is formed. Large diameter passage 12a and small diameter passage 12b
A seat portion 16 on which a ball 14 as a valve body can be seated is formed in an annular shape between the spaces.

The spring retainer plate 18 is fixed to the ball 14 so that the spring retainer plate 18 moves integrally with the ball 14 in the passage direction. The spring retainer plate 18 and the ball 14 are integrally fixed by welding. The spring retainer plate 18 is formed with an opening hole 19 having a sufficiently large hole diameter that connects the upstream side and the downstream side of the spring retainer plate 18.

On the case body 12 upstream of the spring retainer plate 18, an orifice plate 24 is fixed to the inner wall forming the large diameter passage 12a. The orifice plate 24 has a first orifice 26 as a first throttle portion that communicates the upstream side and the downstream side. The spring retainer plate 18 is biased toward the orifice plate 24 by a compression coil spring 28. One end 28a of the compression coil spring 28 is in contact with the step 12c of the case body 12, and the other end 28b is in contact with the spring retainer plate 18. As shown in FIG. 2, the spring retainer plate 18 is provided with an orifice plate 24 when the valve opening when the valve is opened is maximum.
Abut.

The seat portion 1 formed on the case body 12
In No. 6, the contact portion with the ball 14 is tapered so that the ball 14 sits well when the valve is closed and maintains liquid tightness. The orifice plate 24 is set at a predetermined position in order to fix the opening area of the gap formed by the ball 14 and the seat portion 16 when the valve is opened.

The first throttle portion of the present invention corresponds to the first orifice 26 in this embodiment, and the second throttle portion of the present invention is formed by the ball 14 and the seat portion 16 when the valve is opened in this embodiment. Equivalent to the gap. Next, the operation of this flow control valve will be described. (1) In the valve closed state, the flow control valve 10 is in the closed state shown in FIG. Here, assuming that the pressure PH on the upstream side of the orifice plate 24, the pressure PM of the intermediate pressure chamber 30 formed on the downstream side of the orifice plate 24, and the pressure PL on the downstream side of the balls 14, the flow control valve 10 is in the closed state. Then
Since no refrigerant flow has occurred, PH = PM.
Therefore, the force of [differential pressure (PH-PL) x differential pressure effective area Sshut when the valve is closed] pushes the ball 14 in the valve closing direction. At this time, the biasing force generated by the compression coil spring 28 pushes the ball 14 in the valve opening direction, and the force due to the differential pressure is larger than the spring biasing force, so the ball 14 closes the refrigerant passage.

(2) Next, when the valve-closed state is changed to the valve-opened state, the differential pressure (PH-P
L) becomes gradually smaller, and the force due to the differential pressure becomes smaller than the spring biasing force of the compression coil spring 28,
As the ball 14 starts moving in the valve opening direction, a refrigerant flow is generated in the refrigerant passage. When this refrigerant flow occurs, a pressure drop occurs at the outlet side with respect to the inlet side of the first orifice 26, which is lower than the pressure PH on the upstream side of the orifice plate 24 and higher than the pressure PL on the downstream side of the ball 14. The pressure PM is generated in the intermediate pressure chamber 30. At this time, ball 1
The differential pressure acting on 4 becomes (PM-PL), and PM <PH
Therefore, after the refrigerant flow occurs, the valve closed state is instantly changed to the valve opened state.

(3) In the valve open state, the biasing force of the compression coil spring 28 in the valve open direction is the force in the closing direction [differential pressure (PM-P
L) x effective differential pressure area Sopen when the valve is opened. (4) When the valve-opening state is changed to the valve-closing state, in the initial stage, the biasing force of the compression coil spring 28 in the valve-opening direction acts on the ball 14 due to the pressure difference in the closing direction [differential pressure (P
M-PL) x differential pressure effective area Sopen] when the valve is open. Then, the ball 14 starts to move in the valve closing direction. As a result, the intermediate pressure PM approaches the upstream pressure PH (high pressure), and the differential pressure (PM-PL) increases, so that the valve instantaneously closes.

The steps (1) to (4) above are the operations when the flow control valve 30 is changed from the closed state to the open state and from the open state to the closed state. Fig. 3 shows the valve opening differential pressure: 2
In this example, the pressure is set to kg / cm ² and the valve closing pressure difference is set to 3 kg / cm ² .
In the present embodiment, attention is paid particularly to stabilizing the valve behavior from the valve open state to the valve close state. This point will be described in detail below.

In the valve open state, the ball 14 moves in the valve closing direction [differential pressure (PM-PL) x differential pressure effective area Sopen when the valve is open].
When the differential pressure (PM-PL) and the effective area Sopen change, the valve opening force changes greatly. Here, when the phase state of the fluid changes, that is, when the dryness of the fluid changes, for example, when the ratio of the phases of the gas state and the liquid state changes, the valve opening force changes greatly (see FIG. 4).

In the present embodiment, by providing the first orifice 26 on the upstream side of the restriction by the ball 14, the ball 14
The pressure around the inlet is reduced below the inlet pressure of the first orifice 26,
By constantly sending the gas-liquid two-phase liquid around the ball 14, the valve is operated in the state shown in FIG. Therefore, the surroundings of the ball 14 are normally in a liquid state. However, in the present embodiment, a gas-liquid two-phase fluid is sent, so that a stable pressure difference is always maintained regardless of the phase state of the valve inlet. There is an effect that the valve can be closed with.

Further, in this embodiment, the flow control valve 10 provided in the refrigerant circuit constituting the refrigeration cycle is the liquid receiver 3
Since it is provided between the expansion valve 4 and the expansion valve 4, it is effective for reducing the water hammer noise. (Second Embodiment) A second embodiment of the present invention is shown in FIG.

The second embodiment shown in FIG. 6 is aimed at reducing the water hammer noise particularly when the valve is closed. Since the basic structure and operating principle of the valve are the same as those of the first embodiment, the configuration and the effect thereof will be described regarding the different points. In the second embodiment shown in FIG. 6, a semi-low pressure chamber 40 is provided inside the case body 12. The semi-low pressure chamber 40 generates a large amount of gas in the semi-low pressure chamber 40 by making the pressure PL1 of the semi-low pressure chamber 40 during opening of the ball 14 as low as possible. It has a role to reduce absorption.

Inside the case body 12, an intermediate stopper member 42 is fixed to the case body 12 between the orifice plate 24 and the first seat portion 16. The intermediate stopper member 42 has a second seat portion 42a with which the movable plate 43 can come into contact. The ball 14 is a movable plate 43.
It is fixed integrally by welding. One end 28 a of the compression coil spring 28 contacts the inner wall of the case body 12, and the other end 28 b contacts the movable plate 43. The movable plate 43 has a third diaphragm 45. The state shown in FIG. 6 shows a valve open state, and when the ball 14 moves leftward from this valve open state and seats on the seat portion 16, it becomes a valve closed state.

The pressure PL1 in the semi-low pressure chamber 40 is lower than the pressure PH on the upstream side, and the pressure PM in the intermediate pressure chamber 30 is further reduced.
Is equal to or less than the pressure. Therefore, the semi-low pressure chamber 40 has a relatively low pressure close to the pressure PL on the low pressure side, and therefore has a high gas state ratio. Therefore, as can be understood from FIG. 4, there is an effect that the pressure required for closing the valve becomes relatively stable when the degree of dryness of the refrigerant is small or in the supercooled state. That is, by increasing the amount of the refrigerant in the gas state inside the sub-low pressure chamber 40 in which the ball 14 is placed, the behavior of the valve opening operation and the valve closing operation is stabilized.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
Shown in. The third embodiment shown in FIG. 7 is the second embodiment shown in FIG.
In addition to the embodiment, a gas storage chamber 50 is provided inside the case body 12.
It is an example of forming. The gas storage chamber 50 is formed in the upper part of the case body 12, and is connected to the semi-low pressure chamber 40 by the communication passage 52.
Communicate with. The gas storage chamber 50 has a role of storing the gas refrigerant stored in the semi-low pressure chamber 40 in the upper gas storage chamber 50.

In the third embodiment, a semi-low pressure chamber 40 is provided inside the case body 12, and the semi-low pressure chamber 40 is connected to the communication passage 5.
2, the gas storage chamber 50 is communicated. Case body 12
An intermediate stopper member 42 is provided between the orifice plate 24 and the first seat portion 16 inside the case body 12.
It is fixed to. The intermediate stopper member 42 has a second seat portion 42a with which the movable plate 43 can come into contact. The ball 14 is integrally fixed to the movable plate 43 by welding. The compression coil spring 28 has one end 28a.
Contacts the inner wall of the case body 12, and the other end 28b
Is in contact with the movable plate 43. The movable plate 43 has a third diaphragm 45.

When the valve is opened, the semi-low pressure chamber 4 is opened by the first throttle 26.
A large amount of gas refrigerant is generated in the semi-low pressure chamber 40 by making the pressure PL ₁ of 0 as low as possible than the pressure on the upstream side of the orifice plate 24. Then, the water hammer noise is absorbed and reduced when the valve opening state is changed to the valve closing state. At the time of shifting from the valve closed state to the valve opened state, the liquid refrigerant accumulated in the gas storage chamber 50 is gravitationally passed through the communication passage 52 to the semi-low pressure chamber 4
Discharge to 0 by gravity.

(Fourth Embodiment) A fourth embodiment of the present invention is shown in FIG.
Shown in. The fourth embodiment shown in FIG. 8 is a communication passage 6 as a fourth throttle portion that connects the gas storage chamber 50 and the intermediate pressure chamber 30.
In this example, 0 is formed on the case body 12. When the valve is closed,
Liquid is stored in the gas storage chamber 50, the semi-low pressure chamber 40, and the intermediate pressure chamber 30. When shifting from the closed state to the opened state, as shown in FIG.
In the above-described third embodiment shown in FIG. 7, the liquid refrigerant accumulated in the gas storage chamber 50 was discharged from the communication passage 52 to the semi-low pressure chamber 40 by gravity, but in the fourth embodiment shown in FIG. By decompressing and expanding the refrigerant from the communication passage 60 into the gas storage chamber 50, the liquid refrigerant accumulated in the gas storage chamber 50 is forcibly discharged from the communication passage 52 to the semi-low pressure chamber 40. As a result, the water hammer noise at the time of valve closing can be completely prevented even if opening and closing are repeated in a short time such as closing → opening → closing.

(Fifth Embodiment) FIG. 9 shows a fifth embodiment of the present invention.
Shown in. The fifth embodiment shown in FIG. 9 is an intermediate stopper member 1.
8 is an example in which a communication passage 70 as a fifth throttle portion is formed. When the valve is opened, the pressure PL1 of the quasi-low pressure chamber 40 is made as low as possible than the pressure on the upstream side of the orifice plate 24 by the first throttle 26 and the fifth throttle 70, so that a large amount of gas refrigerant is stored in the quasi-low pressure chamber 40. generate. Then, the water hammer noise is absorbed and reduced when the valve opening state is changed to the valve closing state.

When shifting from the valve closed state to the valve opened state, a refrigerant flow is generated around the ball 14 at the initial stage. At this time, a large amount of the refrigerant flows from the gas reservoir 50 through the communication passage 52 to the periphery of the ball 14. By supplying the gas refrigerant, the amount of the refrigerant in the gas state is increased inside the semi-low pressure chamber 40, and the valve opening operation and the valve closing operation are stabilized. (Sixth Embodiment) A sixth embodiment of the present invention is shown in FIG.

The sixth embodiment shown in FIG. 10 is an example in which the inner wall to be the sixth throttle passage 80 is formed in a cylindrical shape in the cylindrical portion of the intermediate stopper member 42 so as to extend in the axial direction. In this example, the pressure of the quasi-low pressure chamber 40 is kept as low as possible while the flow control valve 10 moves from the opened state shown in FIG. 10 to the valve closing direction in the valve closing direction to the right in FIG. This is an example of devising the valve part. That is, when the valve gradually moves to the left from the valve open state shown in FIG. 10, the semi-low pressure chamber 40 immediately before the ball 14 is finally seated on the seat portion 16 with the sixth throttle passage 80 throttled. The pressure difference between the low pressure side and the low pressure side becomes the smallest, and more gas is generated in the semi-low pressure chamber 40 during the valve closing process, and the generation of the water hammer noise is suppressed.

In the first embodiment, the present invention is applied to the flow control valve provided between the liquid receiver 3 and the expansion valve 4, but the flow control valve of the present invention is the other part of the refrigerant circuit that constitutes the refrigeration cycle. Can be installed in the refrigerant circuit. The flow control valve of the present invention can also be applied to fluid passages other than the refrigerant circuit.

[0036]

According to the flow control valve of the first aspect of the present invention, since the operating pressure when the valve is opened and when the valve is closed has a hysteresis, the hysteresis changes the liquid phase of the refrigerant or the gas-liquid two-phase state of the gas phase. Even if there is, there is an effect that a relatively stable valve opening operation or valve closing operation can be performed. This is based on the fact that the opening / closing hysteresis of the valve characteristic is reduced by the presence of the first throttle portion.

Further, the present invention has an effect of a quick action in which the opening / closing operation of the valve is quickly performed. That is, the switching between the valve open state and the valve closed state is performed quickly. Furthermore, according to the present invention, when the flow control valve is provided between the liquid receiver that constitutes the refrigeration cycle circuit and the expansion valve, the water hammer noise that tends to cause noise by providing the flow rate control valve in a state where a gas-liquid two-phase state is likely to occur. Can be effectively reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a closed state of a flow control valve according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an open state of the flow control valve of the first embodiment of the present invention.

FIG. 3 is a time chart showing changes in each pressure chamber and open / close states of valves according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing the relationship between the dryness of the refrigerant and the differential pressure ΔP required for closing the valve of the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a refrigeration cycle circuit to which the first embodiment of the present invention is applied.

FIG. 6 is a schematic sectional view showing a flow control valve of a second embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a flow rate control valve of a third embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a flow rate control valve according to a fourth embodiment of the present invention.

FIG. 9 is a schematic sectional view showing a flow rate control valve of a fifth embodiment of the present invention.

FIG. 10 is a schematic sectional view showing a flow rate control valve of a sixth embodiment of the present invention.

[Explanation of symbols]

 3 Liquid receiver 4 Expansion valve (pressure reducing device) 9 Piping (refrigerant circuit) 10 Flow control valve 12 Case body 12a Large diameter passage (standard passage) 12b Large diameter passage (standard passage) 14 Ball (second throttle portion, valve means) ) 16 first seat portion (second throttle portion, valve means) 18 spring retainer plate 24 orifice plate (first throttle portion) 26 first orifice (first throttle portion) 28 compression coil spring (biasing means) 50 gas reservoir Room

Claims (7)

[Claims] 1. A first throttle portion having a passage opening area smaller than a passage opening area of a standard passage formed inside a case body, and a passage smaller than a passage opening area of a standard passage formed inside the case body. A second throttle portion that has an opening area and is provided downstream of the first throttle portion with respect to the flow of fluid, and is formed between the first throttle portion and the second throttle portion inside the case body. An intermediate pressure chamber, and the second throttle section is a variable throttle that operates by a differential pressure between the intermediate pressure of the intermediate pressure chamber and the pressure on the downstream side of the second throttle section. valve. 2. The flow control valve according to claim 1, wherein the first throttle portion is a fixed throttle having a fixed passage opening area. 3. The valve means for closing the second throttle portion when the differential pressure between the intermediate pressure of the intermediate pressure chamber and the downstream pressure of the second throttle portion is relatively large and opens when the differential pressure is small. The flow control valve according to claim 1, wherein: 4. The flow control valve according to claim 1, wherein a third throttle portion is provided on the downstream side of the second throttle portion with respect to the flow of fluid. 5. A flow control valve according to claim 4, wherein a gas reservoir is provided on a side surface of the intermediate pressure chamber of the flow control valve. 6. A refrigeration cycle apparatus comprising the refrigerant circuit constituting a refrigeration cycle, wherein the flow control valve according to claim 1 is used. 7. A refrigeration cycle comprising the flow control valve according to any one of claims 1 to 5 between a liquid receiver and a pressure reducing device provided in a refrigerant circuit constituting the refrigeration cycle. apparatus.