JPH04254158A - Refrigerating cycle for heat pump type air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for a heat pump type air conditioner.

0002

[Prior Art] Generally, a refrigeration cycle of a heat pump type air conditioner includes a compressor, a four-way switching valve for switching between cooling and heating, a heat exchanger on the heat source side, an expansion valve, and a heat exchanger on the user side. It is well known that the refrigerant can flow reversibly through the switching operation of a four-way switching valve.In the case of such a refrigeration cycle, if a non-reversible expansion valve is used, when the refrigerant flows reversibly, It is necessary to make arrangements so that the refrigerant passes through the expansion valve in the normal flow direction.

[0003] Such a device is disclosed in Japanese Patent Application Laid-Open No. 57-41556, in which two check valves are provided in each parallel circuit connected through an expansion valve. It has been proposed that the refrigerant passing through the expansion valve always flows from the inlet to the outlet.

0004

[Problems to be Solved by the Invention] However, when controlling the refrigerant flow direction using four check valves installed in a parallel circuit as in the above-mentioned known example, there are differences in the operating timing of the individual check valves. Due to changes in the flow rate of the circulating refrigerant, a circuit that bypasses the check valve may be formed, resulting in a circuit that does not pass through the expansion valve.
This may lead to poor refrigerant circulation in the refrigeration cycle.

The present invention has been made in view of the above points, and even if the refrigerant flow direction in the refrigeration cycle is changed, the refrigerant flow direction passing through the expansion valve is reliably kept in the normal direction (that is, the inlet side). The challenge is to make this possible (from the direction toward the exit side).

[0006]

[Means for Solving the Problems] In the present invention, as a means for solving the above problems, as shown in the drawings, a compressor 1, a four-way switching valve 2 for switching between cooling and heating, a heat source side heat exchanger 3, an expansion In the refrigeration cycle of a heat pump type air conditioner, which is provided with a valve 6 and a user side heat exchanger 7, and is configured to allow reversible flow of refrigerant by switching operation of the cooling/heating switching four-way switching valve 2, the heat source side heat exchanger 3 and the user-side heat exchanger 7, the four-way switching valve for switching the flow path so that the refrigerant flowing reversibly between the two heat exchangers 3 and 7 always passes through the expansion valve 6 from the same direction. 4, and one pilot valve 9 for controlling the operation of the four-way switching valve 2 for switching between cooling and heating and the four-way switching valve 4 for switching flow paths.

[0007]

[Function] In the present invention, the following effects can be obtained by the above-mentioned means.

That is, one pilot valve 9 is used to switch the flow direction of the refrigerant supplied to the cooling/heating four-way switching valve 2 and the expansion valve 6, which switches the flow direction of the refrigerant flowing through the refrigeration cycle. The four-way switching valve 4 is simultaneously operated.

[0009]

According to the present invention, the compressor 1, the four-way switching valve for cooling/heating switching 2, the heat source side heat exchanger 3, the expansion valve 6, and the user side heat exchanger 7 are provided, and the four-way switching valve for cooling/heating In a refrigeration cycle of a heat pump type air conditioner in which refrigerant can be reversibly circulated by switching operation of a switching valve 2, both heat exchangers 3, 7 are located between the heat source side heat exchanger 3 and the usage side heat exchanger 7. a four-way switching valve 4 for switching the flow path that switches the flow direction of the refrigerant so that the refrigerant flowing reversibly between them always passes through the expansion valve 6 from the same direction; One pilot valve 9 for controlling the operation of the path switching valve 4 is attached, and the four-way switching valve 2 for cooling/heating switching and the four-way switching valve 4 for switching the flow path can be simultaneously operated by one pilot valve 9. Since the switching operation is made possible, at the time of cooling/heating switching, switching of the flow direction of the refrigerant flowing through the refrigeration cycle and switching of the flow direction of the refrigerant supplied to the expansion valve 6 can be performed simultaneously and reliably, which is different from conventional methods. This has the excellent effect of preventing the formation of a circuit that bypasses the expansion valve 6, which could otherwise occur, and preventing the occurrence of poor refrigerant circulation in the refrigeration cycle.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

As shown in FIG. 1, the refrigeration cycle of the heat pump type air conditioner of this embodiment includes a compressor 1, a four-way switching valve 2 for switching between cooling and heating, a heat exchanger 3 on the heat source side, and a four-way switching valve for flow path switching. It is equipped with a switching valve 4, a receiver 5, an expansion valve 6, a user-side heat exchanger 7, and an accumulator 8, and by the switching operation of the four-way switching valve 2 for cooling/heating, the direction is in the direction of the solid line arrow during cooling operation, and the direction is in the direction of the solid line arrow during heating operation. As shown in the direction of the dotted arrow,
It is said that reversible flow of refrigerant is possible.

In the case of this embodiment, the compressor 1, the four-way switching valve 2 for switching between cooling and heating, the heat source side heat exchanger 3, the four-way switching valve 4 for switching flow paths, the receiver 5, the expansion valve 6, and the accumulator 8 are The heat exchanger 7 is placed in the outdoor unit A, and the user side heat exchanger 7 is placed in the indoor unit B.

[0013] The four-way switching valve 4 for switching the flow path is configured to control the refrigerant flow direction so that the refrigerant flowing reversibly between the heat source side heat exchanger 3 and the usage side heat exchanger 7 always passes through the expansion valve 6. 2 and 3.
As shown, it has the same structure as the four-way switching valve 2 for cooling/heating switching, and its operation is controlled by a shared pilot valve 9.

The four-way switching valve 2 for switching between cooling and heating includes a cylindrical valve body 2A, a pair of pistons 2B, 2C that reciprocate in a connected state within the valve body 2A, and the pistons 2B, 2.
It is provided with a partition plate 2D that connects C, and a switching valve 2E located in the center of the partition plate 2D. The valve body 2A
, a port 2F connected to the discharge pipe 10 of the compressor 1, a port 2G located opposite thereto and connected to the heat source side heat exchanger 3, and a port connected to the usage side heat exchanger 7. 2H and a port 2I connected to the suction pipe 11 (specifically, the accumulator 8) of the compressor 1 are formed. As the switching valve 2E moves, the switching valve 2E switches between the ports 2G and 2I, or between the ports 2H and 2H.
It is supposed to act to selectively communicate with I. The partition plate 2D also has a through hole 2J that connects the port 2F and the port 2H when the port 2G and the port 2I are in a communicating state, and a through hole 2J that connects the port 2H and the port 2I.
Port 2F and Port 2G are connected when
A through hole 2K is formed which communicates with the two. Further, pilot ports 2L, 2M are provided in the valve body 2A at positions facing the pistons 2B, 2C.

On the other hand, the four-way switching valve 4 for flow path switching has the same structure as the four-way switching valve 2 for cooling/heating switching, and has a cylindrical valve body 4A and a valve body 4A connected to each other. A pair of pistons 4B, 4C that reciprocate, and the pistons 4B, 4
It is provided with a partition plate 4D that connects C, and a switching valve 4E located in the center of the partition plate 4D. The valve body 4A
includes a port 4F connected to the heat exchanger 3 on the heat source side, a port 4G located opposite thereto and connected to the receiver 5, a port 4H connected to the expansion valve 6, and the heat exchanger 7 on the usage side. A port 4I connected to is formed. The switching valve 4E changes the port 4 as it moves.
It acts to selectively communicate between G and port 4I, or between port 4H and port 4I. In addition, the partition plate 4D has a through hole 4J that connects the port 4F and the port 4H when the port 4G and the port 4I are connected, and a through hole 4J that connects the port 4H and the port 4I. A through hole 4K is formed which allows the port 4F and the port 4G to communicate with each other when the port 4F and the port 4G are in communication with each other. moreover,
Pilot ports 4L and 4M are provided in the valve body 4A at positions facing the pistons 4B and 4C.

Further, the pilot valve 9 includes a cylindrical valve body 9A, a piston 9B that reciprocates in a connected state within the valve body 9A, and a switching valve 9C integrally formed with the piston 9B. There is. The valve body 9A includes:
A port 9D connected to the port 2F of the four-way switching valve 2 for cooling/heating switching, and a pilot port in the four-way switching valve 2 for switching cooling/heating and the four-way switching valve 4 for switching flow paths located at a position opposite thereto. Ports 9E, 9F connected to 2M, 2L and 4M, 4L, the four-way switching valve 4 for switching the flow path
A port 9G connected to port 4F of is formed. As the switching valve 9C moves, the switching valve 9C switches between the ports 9E and 9G, or between the ports 9F and 9G.
It is supposed to act so as to selectively communicate with the two. Further, the port 9D is communicated with the port 9G via the through hole 9H formed in the piston 9B when the port 9E and the port 9G are in communication state, while the port 9F and the port 9G are in communication with each other. When it is in the state, it is communicated with the port 9E via the internal space of the valve body 9A. Reference numeral 9I is a solenoid for moving the piston 9B forward and backward, and 9J is a return spring.

The refrigeration cycle of the heat pump type air conditioner constructed as described above operates as follows.

During cooling operation, as shown in FIG. 2, the solenoid 9I in the pilot valve 9 is energized and the piston 9B is moved backward against the biasing force of the return spring 9J, so that the discharge gas from the compressor 1 is The refrigerant passes through the port 2F of the four-way switching valve 2 for cooling/heating switching and the ports 9D, 9E of the pilot valve 9 to the pilot ports 2L, 4L of the four-way switching valve 2 for cooling/heating switching and the four-way switching valve 4 for flow path switching.
pistons 2B, 2C and 4B in the four-way switching valve 2 for switching between cooling and heating and the four-way switching valve 4 for switching flow paths,
4C is moved to the right in the drawing. Then, in the four-way switching valve 2 for cooling/heating, port 2F and port 2G
And while port 2H and port 2I are in communication state, in the four-way switching valve 4 for flow path switching, port 4
F and port 4G are placed in communication, and port 4H and port 4I are placed in communication with each other. In other words, the refrigerant discharged from the compressor 1 flows in the direction shown by the solid arrow in FIG.

Also, during heating operation, as shown in FIG. 3, the solenoid 9I in the pilot valve 9 is de-energized and the piston 9B is activated by the return spring 9J.
The gas refrigerant discharged from the compressor 1 is moved forward by the urging force of the compressor 1, and passes through the port 2F of the four-way switching valve 2 for cooling/heating switching and the ports 9D, 9F of the pilot valve 9 to the four-way switching valve 2 for switching between cooling and heating. It is supplied to the pilot ports 2M, 4M of the four-way switching valve 4 for switching the flow path, and the pistons 2B, 2C in the four-way switching valve 2 for cooling/heating switching and the four-way switching valve 4 for switching the flow path.
and 4B and 4C are moved to the left in the drawing. Then, in the four-way switching valve 2 for cooling/heating, port 2F
, and port 2H and port 2G and port 2I are in communication, respectively, while in four-way switching valve 4, port 4F and port 4H and port 4G and port 4I are in communication, respectively. In other words, the refrigerant discharged from the compressor 1 flows in the direction shown by the dotted arrow in FIG.

As described above, according to this embodiment, the four-way switching valve 2 for cooling/heating switching and the four-way switching valve 4 for switching flow paths can be simultaneously operated by one pilot valve 9. Therefore, at the time of switching between cooling and heating, switching of the flow direction of the refrigerant flowing through the refrigeration cycle and switching of the flow direction of the refrigerant supplied to the expansion valve 6 can be performed simultaneously and reliably.

It goes without saying that the present invention is not limited to the configuration of the above-mentioned embodiments, and that the design can be changed as appropriate without departing from the gist of the invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a refrigeration cycle of a heat pump air conditioner according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the state of two four-way switching valves in the refrigeration cycle of the heat pump air conditioner according to the embodiment of the present invention during cooling operation.

FIG. 3 is a sectional view showing the state of two four-way switching valves in the refrigeration cycle of the heat pump air conditioner according to the embodiment of the present invention during heating operation.

[Explanation of symbols]

1 is a compressor, 2 is a four-way switching valve for switching between cooling and heating, 3 is a heat exchanger on the heat source side, 4 is a four-way switching valve for switching flow paths, 6 is an expansion valve, 7 is a heat exchanger on the user side, and 9 is a pilot valve.

Claims (1)

[Claims] 1. A compressor (1), a four-way switching valve (2) for switching between cooling and heating, a heat source side heat exchanger (3), an expansion valve (6), and a user side heat exchanger (7). A refrigeration cycle of a heat pump type air conditioner in which a refrigerant can be reversibly circulated by switching operation of a four-way switching valve (2), the heat exchanger (3) on the heat source side and the heat exchanger (7) on the user side. ) is located between the heat exchangers (3) and (7) and switches the direction of flow of the refrigerant so that the refrigerant flowing reversibly between the heat exchangers (3) and (7) always passes through the expansion valve (6) from the same direction. (4)
and one pilot valve (9) for controlling the operation of the four-way switching valve for cooling/heating switching (2) and the four-way switching valve for flow path switching (4). Conditioner refrigeration cycle.