JP2516626B2 - Two-stage pressure reducing valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a flow control valve used in a heat pump type air conditioner or the like.

2. Description of the Related Art In a heat pump type cooling and heating device, switching between cooling and heating is performed by reversing the flow direction of the refrigerant, but when dehumidification is also attempted, the indoor heat exchanger is cooled and reheated. It is necessary to configure a refrigerant circuit in which the refrigerant circuit is divided into two and an expander is provided therebetween. An improved example of such a refrigerant circuit is disclosed in JP-A-58-106369 (Fig. 7). In this circuit, the outdoor heat exchanger c
Expansion valve f having reversible flow between the indoor heat exchanger b and
Is installed, and the capillary tube h is placed between the indoor heat exchangers a and b.
And a two-way solenoid valve g are provided in parallel. Then, during normal cooling or heating, the electromagnetic valve g is opened to use both the indoor heat exchangers a and b for cooling or heating, and when dehumidifying, the electromagnetic valve g is closed to heat the indoor heat exchanger b to heat the indoor heat exchanger b. The exchanger a is used for cooling. d is a compressor, e
Is a four-way valve.

However, the solenoid valve g in such a circuit needs to be large so as not to hinder the flow of the refrigerant during cooling or heating. Further, since the capillary tube h is used as the expander, it is not possible to control the rise and fall of the room temperature during dehumidification, and if it is attempted to adjust the room temperature at the same time as dehumidification, instead of the capillary tube, multi-step control with a small flow rate or It is necessary to use a valve that can be continuously controlled, such as an electric expansion valve.

Problems to be Solved As described above, in the conventional air conditioner capable of heating and cooling and dehumidifying, if some cooling or heating is attempted in order to achieve a comfortable environment even during dehumidification, instead of the capillary tube, a large-sized Since an expensive control valve must be attached and the operations of a plurality of control valves must be operated synchronously, the control device inevitably becomes complicated, becomes large in size, and costs increase.

Therefore, the present invention is intended to improve the function of a device that is provided between two such indoor heat exchangers and that controls the flow rate of the refrigerant, to make the device compact, and at the same time to prevent an increase in cost. Another object of the present invention is to provide a small-sized flow rate control valve that also serves as an expansion valve, which meets such a purpose.

[Structure of Invention]

Means for Solving the Problems As described above, the object of the present invention is to provide a needle valve that advances and retracts steplessly from the upper valve chamber side with respect to a valve seat provided in a partition that divides the upper valve chamber and the lower valve chamber. In a control valve with a body,
A main valve seat that communicates with the second fluid passage is provided in the lower valve chamber that communicates with the first fluid passage, and a piston-shaped main valve body that is spring-biased toward the main valve seat is vertically moved into the lower valve chamber. A leak passage that is slidably fitted to form a back pressure space between the partition wall and the main valve body, and connects the lower valve chamber and the back pressure space, and the flow resistance is a needle valve. Is greater than the flow resistance at the time of full opening and a sub passage for connecting the upper valve chamber and the second fluid passage is provided.

It is preferable that the needle valve element of the valve of the present invention is advanced and retracted steplessly by incorporating a pulse motor or the like.

The leakage passage connecting the lower valve chamber and the back pressure space may be provided, for example, through the main valve body or on the valve body side, or the main valve body and the lower valve chamber side wall. It may be provided as a gap from the. The flow resistance of the leak passage is larger than the flow resistance of the needle valve when it is fully opened. Therefore, when the needle valve is fully opened, the pressure in the back pressure space is almost equal to the pressure of the upper valve chamber, and thus the pressure of the second fluid passage. Is desirable.

The two-stage pressure reducing valve of the present invention thus configured has the first
When the fluid flows in from the fluid passage, the pressure in the lower valve chamber becomes high, and when the needle valve is closed, the lower valve chamber and the back pressure space are pressure-equalized by the leakage passage, and therefore are closed by the spring. The valve is closed more strongly by the fluid pressure. Then, when the needle valve is opened little by little from this state, the fluid enters the upper valve chamber through the back pressure space, and proceeds to the second fluid passage through the sub passage.

When the needle valve opens further, the flow rate increases, but when the needle valve approaches full opening, the pressure in the back pressure space drops significantly,
The main valve body is pushed up while compressing the spring by the fluid pressure in the lower valve chamber, and the main valve is opened.

On the other hand, when the fluid flows from the second fluid passage, the needle valve is closed to push up the main valve body, and the fluid flows out to the first fluid passage with almost no restriction.

Example An example of the two-stage pressure reducing valve of the present invention is shown in FIG.

Reference numeral 1 denotes a valve main body, an upper lid 11 is attached to an upper portion thereof, and an upper valve chamber 21 is formed between the partition 2 and the upper lid 11 attached inside. A valve seat 22 is provided on the partition wall 2 and is opened and closed by a needle valve element 3 driven by an actuator 8.

Reference numeral 8 is an electric actuator attached to the upper portion of the valve body 1. Reference numeral 81 is a male screw cylinder erected in the upper lid 11 so that the needle valve body 3 can penetrate therethrough, and 82 is a rotor rotatably screwed to the male screw cylinder 81. Reference numeral 83 is a stator coil attached to the outside of the shield tube 84. The rotor 82 and the upper end portion 31 of the needle valve body 3 are rotatably connected, and the rotor 82 causes axial movement along the male screw cylinder 81 as it rotates, but this axial movement is prevented by the spring 85. It is transmitted to the needle valve body 3 so as not to move, and the needle valve body 3 advances and retreats in proportion to the rotation amount of the rotor 82.

A first fluid passage 4 is opened in the side wall of the lower valve chamber 12 in the valve body 1, and a main valve seat 13 communicating with the second fluid passage 5 is formed in the upper surface of the bottom wall. Then, the second fluid passage 5
A sub passage 15 is provided to connect the connection portion 14 with the upper valve chamber 21.

Reference numeral 6 is a piston-shaped main valve body that can slide up and down in the lower valve chamber 12, and 61 is a leak passage that connects the upper back pressure chamber 16 and the lower lower valve chamber 12. Reference numeral 7 is a valve spring provided in the back pressure chamber 16 and is used to connect the main valve body 6 to the main valve seat.
We are pushing toward 13.

FIG. 2 shows an example in which the two-stage pressure reducing valve configured as described above is incorporated in an air conditioning circuit for cooling and heating. In the figure, a and b are indoor heat exchangers, c is an outdoor heat exchanger, d is a compressor, e is a four-way switching valve, f is an expansion valve, and v is a two-stage pressure reducing valve of the present invention.

The operation of the two-stage pressure reducing valve v of the present invention in the air conditioning circuit of FIG. 2 will be described with reference to FIGS.

FIG. 3 shows the state during the heating operation, in which the high temperature refrigerant sent from the compressor d flows from the indoor heat exchanger a through the second fluid passage 5, and at this time, the main valve body 6 is It is pushed up and enters the lower valve chamber 12, and immediately goes to the indoor heat exchanger b through the first fluid passage 4. The refrigerant heat-radiated and condensed in the indoor heat exchangers a and b passes through the expansion valve f, evaporates in the outdoor heat exchanger c, and returns to the compressor d. At this time, the operation of the two-stage pressure reducing valve v allows a large amount of refrigerant to flow while the needle valve is closed.

FIG. 4 shows a state during normal cooling operation.
The refrigerant supplied from the expansion valve f to the indoor heat exchanger b flows into the lower valve chamber 12 through the first fluid passage 4, but since the needle valve element 3 opens the valve seat 22, the upper valve chamber 21 And back pressure chamber 16
Is equalized, and the refrigerant flowing into the back pressure chamber 16 through the leakage passage 61 cannot increase the internal pressure of the back pressure chamber 16 and passes from the upper valve chamber 21 through the sub passage 15 to the second fluid passage. Go to 5. Therefore, the main valve body 6 is pushed up by the pressure of the refrigerant in the lower valve chamber 12, and most of the refrigerant immediately goes from the lower valve chamber 12 to the second fluid passage 5 and enters the indoor heat exchanger a.

FIG. 5 shows a state in which dehumidification is attempted during the cooling operation. When the needle valve is closed from the state shown in FIG. 4, the refrigerant flowing from the back pressure chamber 16 to the upper valve chamber 21 decreases and the pressure in the back pressure chamber 16 rises. At this time, the main valve body 6 of the valve spring 7
The force for pushing down exceeds the force for pushing up the main valve body 6 due to the pressure difference of the refrigerant between the lower valve chamber 12 and the back pressure chamber 16,
Closes the main valve seat 13. As a result, all the refrigerant flowing from the first fluid passage 4 leaks from the lower valve chamber 12 to the leakage passage 61,
The back pressure chamber 16, the valve seat 22, the upper valve chamber 21, and the auxiliary passage 15 are sequentially passed to the second
It goes from the fluid passage 5 to the indoor heat exchanger a.

At the same time, when the expansion valve f is opened, warm refrigerant that has not been completely condensed in the outdoor heat exchanger c flows into the indoor heat exchanger b, the indoor heat exchanger b is heated, and the indoor heat exchanger a is Dehumidifying works by cooling. Furthermore, by adjusting the opening of the needle valve, the operating state during dehumidification can be changed to cooling or heating.

The flow rate characteristic of the two-stage pressure reducing valve v of the present invention as described above is the sixth.
As shown, the flow in the opposite direction is unrestricted.

〔The invention's effect〕

The two-stage pressure reducing valve of the present invention can perform precise flow rate control at a low flow rate, and functions to switch to a high flow rate by pilot operation when the flow rate control range is exceeded. Therefore, by installing a control valve in the middle of two indoor heat exchangers in a cooling and heating apparatus with a dehumidifying function, a highly functional and economical apparatus can be constructed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a two-stage pressure reducing valve of the present invention, FIG. 2 is an example of a cooling / heating refrigeration circuit using the two-stage pressure reducing valve of the present invention, and FIGS. FIG. 6 is a cross-sectional view for explaining the operating condition of the step-type pressure reducing valve, FIG. 6 is a graph showing an example of flow rate characteristics of the two-step pressure reducing valve of the present invention, and FIG. 7 is an example of a conventional cooling / heating refrigeration circuit. 1 ... Valve body, 11 ... Upper lid, 12 ... Lower valve chamber, 13 ... Main valve seat, 15 ... Sub passage, 16 ... Back pressure chamber, 2 ... Partition wall, 21 ...
… Upper valve chamber, 22 …… Valve seat, 3 …… Needle valve body, 4 ……
First fluid passage, 5 ... Second fluid passage, 6 ... Main valve body, 61
...... Leakage passage, 7 ...... Valve spring, 8 ...... Actuator,
81 …… Male screw cylinder, 82 …… Rotor, 85 …… Spring, a, b ……
Indoor heat exchanger, c ... Outdoor heat exchanger, d ... Compressor, e
...... Four-way switching valve, f ... Expansion valve, g ... Solenoid valve, h ...
Capillary tube, v ... Two-stage pressure reducing valve.

Claims (1)

(57) [Claims] 1. A control valve provided with a needle valve body which moves steplessly from the upper valve chamber side with respect to a valve seat provided in a partition wall that divides the upper valve chamber and the lower valve chamber, and A main valve seat communicating with the second fluid passage is provided in the communicating lower valve chamber, and a piston-shaped main valve body biased by a spring toward the main valve seat is vertically slidably fitted in the lower valve chamber. Is a leakage passage that establishes a back pressure space between the partition wall and the main valve body and connects the lower valve chamber and the back pressure space, and the flow resistance is a flow passage when the needle valve is fully opened. A two-stage pressure reducing valve, characterized in that it is provided with an auxiliary passage which is larger than resistance and which connects the upper valve chamber and the second fluid passage.