JP3207489B2 - Constant pressure expansion valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type refrigeration cycle used for both air conditioning and heating, for adiabatically expanding a refrigerant so that the pressure of the refrigerant passing through the evaporator is constant, and sending the refrigerant to the evaporator. It relates to a constant pressure expansion valve.

[0002]

2. Description of the Related Art In a heat pump type refrigeration cycle, the flow of refrigerant in the refrigeration cycle is reversed by cooling / heating switching, and the evaporator and the condenser are switched.

Therefore, a temperature-sensitive cylinder or a pressure equalizing tube cannot be used to control the operation of the expansion valve, and the opening of the expansion valve is generally automatically adjusted by a stepping motor.

[0004]

However, in order to control the expansion valve by a stepping motor so that the pressure of the refrigerant passing through the evaporator becomes constant, information on the room temperature and pressure on the refrigerant is detected. A signal indicating the rotation angle must be given to the stepping motor from both the detection signals. Therefore, there is a disadvantage that the detection circuit and the control circuit are extremely complicated and expensive.

[0005] Therefore, it is conceivable to use a constant pressure expansion valve which can keep the pressure of the refrigerant passing through the evaporator constant by a valve mechanism. However, the conventional constant pressure expansion valve has been used when the flow of the refrigerant is unidirectional. Since it only functions, it cannot be used for a heat pump refrigeration cycle.

Accordingly, the present invention provides a bidirectional constant-pressure expansion in which the pressure of a refrigerant passing through an evaporator can be easily and automatically controlled to be constant regardless of the flow direction of the refrigerant in a heat pump type refrigeration cycle. The purpose is to provide a valve.

[0007]

To achieve the above object, a constant pressure expansion valve according to the present invention comprises a pair of heat pump type refrigeration cycles arranged in a heat pump type refrigeration cycle capable of selectively flowing refrigerant in an arbitrary direction. A constant pressure expansion valve provided in the refrigerant flow path between the heat exchangers, arranged in series with the refrigerant flow path to open and close the refrigerant flow path, by the pressure of the refrigerant in the refrigerant flow path The one located on the downstream side is opened and the one located on the upstream side is pressed in the closing direction, and the pressure of the refrigerant passing through the heat exchanger located on the downstream side of the pair of heat exchangers. Valve opening control means for controlling the valve element located on the upstream side in the opening direction so as to keep the valve element constant.

[0008]

The direction of the flow of the refrigerant is reversed by switching between cooling and heating. In any case, the heat exchanger disposed downstream of the expansion valve becomes the evaporator.

The valve element which is located upstream of the pair of valve elements and is pushed in the closing direction by the pressure of the refrigerant,
Energization control in the opening direction is performed by the valve opening control means so that the pressure of the refrigerant passing through the evaporator becomes constant.

[0010]

An embodiment will be described with reference to the drawings. FIG.
This figure shows a heat pump type refrigeration cycle in which a refrigerant can be selectively flowed in an arbitrary direction so that it can be used for both cooling and heating. Reference numeral 1 denotes a compressor, and 2 denotes an accumulator.

One of the pair of heat exchangers 3 and 4 arranged in the refrigeration cycle is placed indoors, and the other heat exchanger 4 is placed outdoors. The expansion valve 1 is provided in the middle of the refrigerant flow path 5 connecting the two heat exchangers 3 and 4.
0 is provided.

6 is a four-way valve for changing the direction of the flow of the refrigerant. FIG. 2 shows that the high-pressure refrigerant compressed by the compressor 1 is first sent to the outdoor heat exchanger 4 and then expanded.
The state of cooling which is sent to the indoor heat exchanger 3 through 0 is shown. Here, the indoor heat exchanger 3 functions as an evaporator.

FIG. 3 shows the compressor 1 by switching the four-way valve 6.
This shows a heating state in which the high-pressure refrigerant compressed in the first step is sent to the indoor heat exchanger 3 and then sent to the outdoor heat exchanger 4 via the expansion valve 10. Here, the indoor heat exchanger 3 functions as a condenser.

FIG. 1 shows an expansion valve 10. A pair of spherical valve bodies 11 and 12 are connected in series with the refrigerant flow path 5 at left and right portions where the refrigerant flow path 5 is formed in a substantially ∩ shape. Are located in

[0015] Valve seats 13 and 14 are formed immediately above the valve bodies 11 and 12, respectively. When the valve bodies 11 and 12 are pressed against the valve seats 13 and 14, the valves are closed. When there is a gap between the valve seats 13, 14 and the valve bodies 11, 12, the flow rate of the refrigerant is adjusted according to the size of the gap.

A valve receiver 1 is provided directly below the valve bodies 11 and 12.
5, 16 are formed. Valve bodies 11 and 12 are valve receiver 1
The times when the valves 5 and 16 are hit are the fully opened state of the valve. The valve bodies 11 and 12 arranged in this way are provided on the high pressure side,
That is, the valve element (the valve element 11 in FIG. 1) positioned upstream of the flow of the refrigerant is pressed toward the valve seat 13 by the pressure of the refrigerant to close the refrigerant flow path 5, and the low pressure side, that is, the flow of the refrigerant The valve element (the valve element 12 in FIG. 1) located downstream of the
It is pressed and opened toward the valve receiver 16 by the pressure of the refrigerant.

When the upstream valve element 11 is separated from the valve seat 13, the refrigerant corresponding to the width of the gap flows downstream while adiabatically expanding. Above this part, there is provided a diaphragm chamber 18 air-tightly partitioned by a flexible diaphragm 17. The outer surface of the diaphragm 17 communicates with the atmosphere, and the inner surface of the diaphragm 17 communicates with the communication hole 2.
The valve 1 communicates with the refrigerant flow path 5 between the two valve bodies 11 and 12 via the valve 1.

Therefore, the pressure inside the diaphragm chamber 18 (the space on the inner surface side of the diaphragm 17) is the same as the pressure in the refrigerant flow path 5 between the two valve bodies 11 and 12, and this is the same as the heat on the downstream side serving as an evaporator. It is the same as the refrigerant pressure at the inlet of the exchanger 3 or 4.

The central portion of the diaphragm 17 is sandwiched between the diaphragm receiving members 19 and 20 from both sides. Further, rods 22 and 23 having one ends fixed to the respective valve elements 11 and 12 are connected to the diaphragm chamber 18.
With a head inside. Therefore, when the diaphragm 17 moves inward of the diaphragm chamber 18, the valve bodies 11 and 12 are moved by the inner diaphragm receiving member 19 to the valve seat 1.
The rods 22 and 23 are pushed down in a direction away from 3,14.

The outer diaphragm receiving member 20 is pressed from above by a compression coil spring 25 via a rod 24 and a movable iron core 32. 26 is a spring receiver, 27 is
An adjusting screw for adjusting the urging force of the compression coil spring 25.

The movable iron core 32 forms a solenoid together with the electromagnetic coil 31, and the electromagnetic force acting on the movable iron core 32 in the axial direction changes by changing the magnitude of the current flowing through the electromagnetic coil 31.

As described above, the diaphragm 17 is pressed by a constant force from the outside (the upper side in FIG. 1) by the compression coil spring 25, and the force for pushing the diaphragm 17 in accordance with the value of the current flowing through the electromagnetic coil 31. Changes.

The control circuit 35 supplies a current having a magnitude corresponding to a difference between a temperature sensor (not shown) for detecting room temperature and a set temperature to the electromagnetic coil 31. According to the constant-pressure expansion valve of the above-described embodiment configured as described above, the diaphragm 17 is pushed with a constant force from the outside unless the current supplied to the electromagnetic coil 31 is changed. Balance with pressure.

Accordingly, the movement of the diaphragm 17 causes the valve element 11 on the upstream side to maintain the balance.
Is controlled so that the pressure in the diaphragm chamber 18, that is, the inlet pressure of the evaporator, is always kept constant.

When the value of the current supplied to the electromagnetic coil 31 is changed by an output signal from the control circuit 35 based on the temperature information, the inlet pressure of the evaporator is kept at a constant pressure corresponding to the change.

When the four-way valve 6 is switched and the flow of the refrigerant is in the opposite direction to that in FIG. 1, the state of the pair of valve bodies 11 and 12 is only reversed, and the downstream of the evaporator is formed. The inlet pressure of the side heat exchanger is controlled to be constant.

FIGS. 4 to 6 show a second embodiment of the present invention, in which the outlet pressure of the evaporator is kept constant. That is, as shown in FIG.
No communication hole is provided between the diaphragm chamber 18 and the diaphragm chamber 18. As shown in FIGS. 5 and 6, the inside of the diaphragm chamber 18 and the refrigerant flow paths outside the heat exchangers 3 and 4 are connected by communication pipes 41 and 42, respectively.

A slide valve 44 in which spherical valves 44b and 44c are fixed to both ends of a rod 44a is provided in a pipe line on the side of the expansion valve 10 to which both communicating pipes 41 and 42 are connected to face each other.
Is arranged.

The slide valve 44 has two communicating pipes 41, 4
Due to the pressure difference inside 2, the slides close the mouths of the communication pipes 41 and 42 on the high pressure side. Therefore, the pressure in the diaphragm chamber 18 becomes equal to the pressure on the outlet side of the heat exchangers 3 and 4 on the downstream side, which is the evaporator, and the outlet pressure of the evaporator is changed regardless of the direction of the flow of the refrigerant. It is kept constant.

[0030]

According to the constant pressure expansion valve of the present invention, the valve element located on the upstream side of the pair of valve elements provided in the refrigerant flow path between the pair of heat exchangers has the heat exchange element on the downstream side. The opening pressure is urged by the valve opening control means so that the pressure of the refrigerant passing through the heater becomes constant, so that the same pressure control is performed even if the flow of the refrigerant is reversed by switching between the cooling and heating, and the evaporation is performed. Pressure of the refrigerant passing through the downstream heat exchanger
It has an excellent effect that it can be easily and accurately controlled to be constant without detecting a pressure signal.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an expansion valve according to a first embodiment.

FIG. 2 is a schematic view of a refrigeration cycle in a cooling state according to the first embodiment.

FIG. 3 is a schematic view of a refrigeration cycle in a heating state according to the first embodiment.

FIG. 4 is a front sectional view of an expansion valve according to a second embodiment.

FIG. 5 is a partial side sectional view of an expansion valve according to a second embodiment.

FIG. 6 is a schematic view of a refrigeration cycle of a second embodiment.

[Explanation of symbols]

 Reference Signs List 3 heat exchanger 4 heat exchanger 5 refrigerant flow path 11 valve element 12 valve element 13 valve seat 14 valve seat 17 diaphragm 18 diaphragm chamber 25 compression coil spring 30 solenoid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 41/06

Claims (1)

(57) [Claims] 1. A constant-pressure expansion valve provided in a refrigerant flow path between a pair of heat exchangers disposed in a heat pump type refrigeration cycle capable of selectively flowing a refrigerant in an arbitrary direction, The refrigerant flow path is arranged in series with the refrigerant flow path so as to open and close, and the pressure of the refrigerant in the refrigerant flow path causes the one located on the downstream side to be opened and the one located on the upstream side to be pushed in the closing direction. A pair of valve elements, and urges the valve element located on the upstream side in the opening direction so as to keep the pressure of the refrigerant passing through the heat exchanger located on the downstream side of the pair of heat exchangers constant. And a valve opening control means for controlling the pressure.