JP3418271B2 - Two-way 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 constant pressure expansion valve for adiabatically expanding a refrigerant so as to keep a constant pressure and sending it to an evaporator in a heat pump type refrigeration cycle used for both heating and cooling.

[0002]

2. Description of the Related Art In a heat pump type refrigeration cycle,
By reversing the flow direction of the refrigerant between the indoor heat exchanger and the outdoor heat exchanger, the heat exchanger on the downstream side becomes an evaporator, and the cooling state and the heating state are switched. In either case, it is necessary to adiabatically expand the refrigerant so that the pressure of the refrigerant sent to the evaporator is constant.

Therefore, in the past, two constant pressure expansion valves for cooling and for heating were arranged in parallel, and a check valve was connected to each of them, whichever was used for cooling and heating. One of the constant pressure expansion valves had to function.

[0004]

However, such a structure in which two constant pressure expansion valves for cooling and for heating are arranged in parallel and a check valve is connected to each of them is one constant pressure expansion valve. Is not always functioning, which means wasteful equipment cost.

Therefore, an object of the present invention is to provide a bidirectional constant pressure expansion valve that functions in both the cooling and heating states and does not waste the device cost.

[0006]

In order to achieve the above object, the bidirectional constant pressure expansion valve of the present invention is provided with a refrigerant passage pipe connected between a pair of heat exchangers in a heat pump type refrigeration cycle. A pressure regulating chamber formed of the formed space, a pressure sensitive body arranged in the pressure regulating chamber so that the length in the pipe axis direction changes in accordance with the pressure of the refrigerant in the pressure regulating chamber, and the pressure sensitive chamber. A pair of valve bodies connected to both ends of the body and arranged to change the flow passage area of the refrigerant on both sides of the pressure adjusting chamber, and the flow direction of the refrigerant in the refrigerant flow passage pipe changes. Thereby, the pressure-sensitive body moves in the flow direction of the refrigerant in the pressure regulating chamber, the valve body located on the downstream side of the pair of valve bodies is fully opened, and the valve body portion located on the upstream side is opened. It is characterized in that it serves as a throttle portion for adiabatically expanding the refrigerant.

When the pressure of the refrigerant in the pressure-sensitive chamber increases, the length of the pressure-sensitive body is shortened, whereby the valve element located on the upstream side is attracted to the pressure-sensitive chamber side and the pressure-sensitive chamber. It is preferable that the area of the refrigerant passage on the inlet side is narrowed, and as a result, the refrigerant pressure in the pressure sensitive chamber and the refrigerant passage pipe on the downstream side is maintained constant.

[0008]

When the flow direction of the refrigerant in the refrigerant flow pipe changes, the pressure-sensitive body in the pressure-sensitive chamber moves in the flow direction, and as a result, the valve element located downstream of the pair of valve elements is fully opened. Refrigerant pressures in the pressure-sensitive chamber and in the downstream-side refrigerant flow path pipe become equal, and the valve body portion located on the upstream side serves as a throttle portion, so that the refrigerant passing therethrough adiabatically expands.

The length of the pressure-sensitive body is shortened as the refrigerant pressure in the surrounding pressure-sensitive chamber increases, whereby the valve element located on the upstream side is attracted to the pressure-sensitive chamber side and the inlet of the pressure-sensitive chamber. The flow passage area is narrowed, and as a result, the refrigerant pressure in the pressure sensitive chamber and the downstream refrigerant passage pipe is maintained constant.

[0010]

Embodiments will be described with reference to the drawings. Figure 2
It shows a cooling and heating device using a heat pump type refrigeration cycle, and the device is divided into an indoor unit 10 placed indoors and an outdoor unit 20 placed outdoors.

An indoor heat exchanger 11 is arranged in the indoor unit 10, the outdoor unit 20 has an outdoor heat exchanger 21, a compressor 22 for compressing a refrigerant, and a liquid refrigerant in the compressor 22. An accumulator 23 for preventing the return is arranged, and a refrigerant circulates them. Further, a four-way valve 24 for switching the flow direction of the refrigerant to be reversed between the cooling time and the heating time is arranged in the middle of the refrigerant flow path.

On the side of the outdoor unit 20, the indoor heat exchanger 11
Refrigerant flow path pipe 1 for connecting and communicating with the outdoor heat exchanger 21
A bidirectional constant-pressure expansion valve 30 for adiabatically expanding the refrigerant and sending it to the downstream side at a constant pressure is inserted and connected in the middle of.

FIG. 1 shows a bidirectional constant pressure expansion valve 30. The bidirectional constant-pressure expansion valve 30 is configured in a divided portion of the refrigerant flow path pipe 1, is surrounded by a cylindrical case 31 fixed to the refrigerant flow path pipe 1 on both sides, and has a space inside thereof. It is a pressure regulation chamber 32. Case 31 and refrigerant flow pipe 1
The connection portion with and is sealed by a sealing member, and the pressure adjusting chamber 32 is configured to be airtight to the outside.

A pressure sensitive body 50 is housed in the pressure adjusting chamber 32. In the pressure sensitive body 50, discs 52 are airtightly fixed to both ends of a bellows 51 having a bellows tubular shape that is expandable and contractible in the axial direction of the pressure regulating chamber 32, and a compression coil spring 54 is mounted between the discs 52. It is configured. And
The pressure inside the pressure sensitive body 50 is set to a negative pressure.

The disks 52 on both sides are urged by a compression coil spring 54 so as to be expanded in the axial direction.
Is in contact with the outer stoppers 34a and 34b formed by the end members (both wall surfaces of the pressure adjusting chamber 32) of the refrigerant flow pipe 1 when there is no influence of the refrigerant pressure.

Therefore, both outer stoppers 34a, 34
The distance between b is the maximum axial length Lo of the pressure sensitive body 50,
The axial length L of the pressure sensitive body 50 is shorter than Lo by the length ΔL of the pressure sensitive body 50 contracted by the influence of the refrigerant pressure.

Inside the compression coil spring 54, an inner stopper 55 in the shape of a bowl cap is arranged so as to project from both discs 52 so as to face inward, and an axial direction of a gap previously formed between both discs 52. Length is 50
Has a length (ΔLmax) that allows maximum contraction. Reference numerals 56 and 57 are connecting members that connect the inner stoppers 55 with play in the axial direction.

Outside the outer stoppers 34a, 34b, tapered valve seats 35a, 35b are formed, which taper toward the inner side of the pressure sensitive body 50, respectively.
a and 36b are arranged to face the valve seats 35a and 35b from the outside.

The valve seats 35a and 35b and the valve body 36 are
Gap portions with a and 36b are throttle portions 41a and 41b for adiabatically expanding the refrigerant. In the pressure adjusting chamber 32, the space between the inner peripheral surface of the case 31 and the bellows 51 serves as a refrigerant flow path.

The effective pressure receiving areas of both valve bodies 36a and 36b are set to be equal. However, when it is desired to change the expansion characteristics of the refrigerant between cooling and heating, both valve elements 36
The effective pressure receiving areas of a and 36b may be different.

Rods 37a and 37b are respectively interposed between the valve bodies 36a and 36b and the disks 52 at both ends of the pressure sensitive body 50, and both valve bodies 36a and 36b are valve seats 35a from the outside. , 35b toward the compression coil spring 3
It is urged by 8a and 38b.

Reference numerals 39a and 39b are receiving members interposed between the compression coil springs 38a and 38b and the valve bodies 36a and 36b. Reference numerals 40a and 40b denote spring receiving nuts screwed into the refrigerant flow path pipe 1 so as to receive the other ends of the compression coil springs 38a and 38b, and by rotating, spring force of the compression coil springs 38a and 38b. Can be adjusted.

In the embodiment constructed as described above, the axial length L of the pressure sensitive body 50 is determined by the spring force of the three compression coil springs 54, 38a, 38b and the pressure sensitive body 50.
Determined by the balance of internal and external pressure. Therefore, the axial length L of the pressure sensitive body 50 is determined by the refrigerant pressure Px in the pressure adjusting chamber 32.
Will be determined by

FIG. 1 shows a state during cooling in which the refrigerant flows from the outdoor heat exchanger 21 on the left side to the indoor heat exchanger 11 on the right side, and the inside of the refrigerant flow pipe 1a on the upstream side is shown. The refrigerant pressure Pa is the refrigerant pressure Pb in the refrigerant passage pipe 1b on the downstream side.
It is higher, that is, Pa> Pb.

In this state, as shown in FIG. 1, the pressure sensitive body 50 is pressed to the right side by the flow of the refrigerant, so that the downstream valve body 36b is fully opened.
As a result, the refrigerant pressure Px in the pressure regulation chamber 32 becomes equal to the refrigerant pressure Pb in the downstream refrigerant flow pipe 1b. That is, Px = P
b. Then, the throttle portion 4 of the valve element 36a on the upstream side
1a serves as a throttle for adiabatically expanding the refrigerant.

As a result, when the refrigerant pressure Pb in the refrigerant passage pipe 1b on the downstream side decreases, the refrigerant pressure Px in the pressure adjusting chamber 32 also decreases by the same amount, and L increases accordingly, so that the valve element 36a on the upstream side. Moves in the opening direction, and the refrigerant channel pipe 1a on the upstream side
From this, the flow rate of the refrigerant sent into the pressure regulation chamber 32 increases.
Then, Px becomes large, so that L contracts, and the flow rate of the refrigerant fed into the pressure regulation chamber 32 from the upstream refrigerant flow pipe 1a decreases.

On the contrary, when the refrigerant pressure Pb in the downstream refrigerant flow pipe 1b rises, the refrigerant pressure Px in the pressure adjusting chamber 32 also rises by the same amount, and L contracts accordingly, so that the upstream valve body Three
6a moves in the closing direction, and the flow rate of the refrigerant fed into the pressure regulation chamber 32 from the upstream refrigerant flow pipe 1a decreases. Then, since Px becomes smaller, L becomes longer, and the flow rate of the refrigerant sent from the refrigerant passage pipe 1a on the upstream side into the pressure adjusting chamber 32 increases.

As a result of such operation, the constant pressure expansion valve 30 operates so that L is always constant. It is the pressure regulation room 3
That is, the refrigerant pressure Px in 2 or the refrigerant pressure Pb in the downstream refrigerant flow pipe 1b becomes constant, and the refrigerant pressure sent to the evaporator 11 is maintained constant.

Since the effective pressure receiving area of the upstream valve body 36a is much smaller than the effective pressure receiving area of the disk 52 of the pressure sensitive body 50, the refrigerant pressure P in the upstream refrigerant flow pipe 1a is increased.
a has almost no effect on the operation of the pressure sensitive body 50. When there is an influence, the pressure Px at which L becomes constant is
Only changes.

In the above operation, the refrigerant pressure Pa in the upstream refrigerant flow pipe 1a is changed to the refrigerant pressure Pb in the downstream refrigerant flow pipe 1b.
In the case of a lower heating state, that is, in the case of Pa <Pb, the operation is exactly the same as the above except that the left and right sides are reversed.

[0031]

According to the present invention, when the flow direction of the refrigerant in the refrigerant flow pipe changes, the pressure sensitive body in the pressure sensitive chamber moves in the flow direction and is positioned on the downstream side of the pair of valve bodies. When the valve body is fully opened and the refrigerant pressures in the pressure-sensitive chamber and the downstream side refrigerant flow path pipe become equal, the valve body portion located on the upstream side becomes a throttle portion and the refrigerant passing therethrough adiabatically expands, so the refrigerant The refrigerant can be adiabatically expanded regardless of whether the flow direction is in the cooling or heating state.

The length of the pressure sensitive body is shortened when the pressure of the refrigerant in the surrounding pressure sensitive chamber is increased, whereby the valve element located on the upstream side is attracted to the pressure sensitive chamber side and the inlet of the pressure sensitive chamber. Since the flow passage area is narrowed and the pressure of the refrigerant in the pressure-sensitive chamber and in the downstream refrigerant flow pipe is kept constant, the refrigerant can be expanded at a constant pressure by the same device in both cooling and heating.

[Brief description of drawings]

FIG. 1 is a sectional view of a bidirectional constant pressure expansion valve according to an embodiment of the present invention.

FIG. 2 is an overall schematic view of a refrigeration cycle according to an embodiment of the present invention.

[Explanation of symbols]

1 Refrigerant flow pipe 30 bidirectional constant pressure expansion valve 32 Pressure regulation chamber 50 pressure sensitive body 36a, 36b valve body 41a, 41b throttle part

Claims (2)

(57) [Claims] 1. A pressure regulation chamber comprising a space formed in the middle of a refrigerant flow pipe connected between a pair of heat exchangers in a heat pump type refrigeration cycle, and a pressure regulation chamber corresponding to the pressure of the refrigerant in the pressure regulation chamber. And a pressure-sensitive body disposed in the pressure-adjusting chamber so that the length in the tube axis direction changes, and the flow passage area of the refrigerant is connected to both ends of the pressure-sensitive body on both sides of the pressure-adjusting chamber. And a pair of valve bodies arranged so as to change, the pressure sensitive body moves in the flow direction of the refrigerant in the pressure regulating chamber by changing the flow direction of the refrigerant in the refrigerant flow path pipe, A bidirectional constant-pressure expansion valve characterized in that the valve element located on the downstream side of the pair of valve elements is fully opened, and the valve element located on the upstream side serves as a throttle for adiabatically expanding the refrigerant. . 2. The pressure-sensitive body is shortened in length as the refrigerant pressure in the pressure-sensitive chamber increases, whereby the valve element located on the upstream side is attracted to the pressure-sensitive chamber side and the pressure-sensitive chamber. The bidirectional constant-pressure expansion valve according to claim 1, wherein the refrigerant flow passage area on the inlet side is narrowed, and as a result, the refrigerant pressure in the pressure sensing chamber and the downstream refrigerant flow passage pipe is maintained constant.