JPH0127274B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system using a scroll compressor, and specifically relates to flow rate restriction in a refrigeration cycle.

A scroll compressor consists of a set of fixed scrolls with scroll-shaped teeth on a base plate, an orbiting scroll, and a space (compression chamber) formed by the base plate as it moves toward the center of the scroll. It has a scroll compression mechanism that moves both scrolls relative to each other so as to reduce the volume of the space (compression chamber). The relative movement is performed by converting rotational movement into differential movement by the shaft of an electric motor connected to the orbiting scroll. Some conventional refrigeration systems using scroll compressors are of the injection type, in which capacity is increased by injecting high-pressure refrigerant gas into a space (compression chamber) of the refrigeration cycle.

However, no consideration has been given to so-called unload operation, in which the discharge amount of the compressor is reduced by increasing or decreasing the load on the refrigeration system.

The present invention has been made in view of the above points, and provides a refrigeration system using a scroll compressor whose capacity can be increased by injection extraction during heating operation, and which can perform unloading operation during cooling operation. The purpose is to

In order to achieve the above object, the present invention provides a four-way switching valve connected to the suction side and discharge side of a scroll compressor, one side of an outdoor heat exchanger, and one side of an indoor heat exchanger, and A first check valve and a first expansion valve, which are arranged in series, and a second check valve and a second expansion valve, which are arranged in series in the refrigerant pipes connected to the other side of the heat exchanger and the other side of the indoor heat exchanger, respectively, are arranged in parallel. and the first check valve and the second check valve are arranged so as to stop the flow in opposite directions, and the refrigeration cycle can perform cooling operation and heating operation by switching the four-way switching valve. and when the load decreases during cooling operation between the refrigerant pipe connected to the four-way switching valve of the refrigeration cycle and one side of the indoor heat exchanger and the compression chamber of the scroll compressor, the scroll An unloading control means for causing a part of the high-pressure refrigerant in the compression chamber of the compressor to flow out into the refrigerant pipe is provided, and an unloading control means is provided between the other side of the indoor heat exchanger and the compression chamber of the scroll compressor for heating operation. An injection control means is provided for injecting high-pressure refrigerant from the other side of the indoor heat exchanger into the compression chamber when it is necessary to increase the discharge amount of the scroll compressor.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a scroll compressor used in the refrigeration system of the present invention, and FIG. 2 is a sectional view of a scroll tooth portion.

Reference numeral 1 denotes an airtight container, and inside the airtight container 1, a scroll compressor section 2 and an electric motor section 3 are connected by a crankshaft 4. The scroll compressor section 2 is composed of a pair of fixed scrolls 5 and orbiting scrolls 6 each having scroll teeth on a base plate, and a frame 7 fixed to the fixed scrolls 5 and housing the orbiting scrolls 6. ing. The frame 7 is fixed to the closed container 1. Also,
The electric motor section 3 consists of a stator 3a and a rotor 3b, and the rotor 3b is fixed to the crankshaft 4. 7a and 7b are bearings for the crankshaft 4. Reference numeral 8 denotes a rotation prevention mechanism, which is constituted by a protrusion of the orbiting scroll 6 and a protrusion of the frame 7. Reference numeral 9 denotes a back pressure chamber, which is formed in the frame 7 on the back side of the orbiting scroll 6, and the back pressure chamber 9 sucks the refrigerant gas formed by the orbiting scroll 6 and the fixed scroll 5 through a pressure equalization hole 10. It is communicated with the space (compression chamber) after completion. 11 is a suction pipe, one end of which is connected to the suction chamber 11a of the fixed scroll 5.
The other end is open so as to pass through the closed container 1 and be connected to an external device. Reference numeral 12 denotes a discharge port, which is bored in the center of the scroll of the fixed scroll 5, and has a hole in the center of the fixed scroll 5.
It is opened inward. 13 is a discharge pipe. 1
Reference numeral 4 denotes an oil reservoir in which lubricating oil is stored so that an oil supply device (not shown) built into the shaft end of the crankshaft 4 is immersed therein. Reference numeral 15 indicates one or more holes or elongated holes, which are bored in the fixed scroll 5 toward the space (compression chamber) 5a where the suction stroke has been completed. Reference numeral 16 denotes a connecting pipe that passes through the closed container 1 and is connected to a backflow restriction valve (described in detail later with reference to FIG. 8; drawing reference numbers 17 and 32) disposed outside the closed container 1.

FIG. 3 is a sectional view of the backflow restriction valve 17, which constitutes a part of the unloading control means. Connecting pipe 1
Reference numeral 8 denotes an opening connected to the low-pressure side refrigerant passage of the refrigeration cycle, and forms a passage at right angles to the connecting pipe 16. 17a is a valve part formed in the middle part of the right angle passage, and a valve seat 17c is formed on the main body side.
and a valve stem 17d. Reference numeral 17b denotes a spring, which is installed between the spring receiver 17e at the end of the valve rod 17d and the other spring receiver 17f fixed to the inside of the main body. A spring force always acts to move the valve stem 17d away from the valve seat 17c. 17g is the gap when the valve is open.

As can be easily seen from FIG. 3, this valve is essentially a check valve that prevents downward flow.

However, whereas the valve spring of a normal check valve acts in the closing direction, the valve spring 17b of this valve (FIG. 3) urges the valve stem d in the valve opening direction.

Therefore, it acts as a check valve against a large amount of backflow (downflow) that overcomes the valve spring 17b, and balances the valve spring 17b with the clearance 1.
For backflow that leaves 7g, the flow rate is suppressed.

This valve 17 (FIG. 3) is a backflow restriction valve in the above sense.

The above-mentioned backflow restriction valve 17 is used in the refrigeration cycle shown in FIG.

This FIG. 4 is an explanatory diagram of the present invention, and is incomplete as an embodiment. Combining the cycle in Figure 6, which will be explained later, and the cycle in Figure 4,
A complete example (for a complete example,
This will be described later with reference to FIG. Figures 4 and 6 are
FIG. 2 is a partial explanatory diagram of essential requirements of the present invention.

Reference numeral 19 shown in FIG. 4 is a scroll compressor, and the details of its specific construction are as described with reference to FIG. 1.

A four-way switching valve 20 is switchably connected to the scroll compressor 19 via a discharge pipe 19 and a suction pipe 19b of the scroll compressor 19. 2
1 is an outdoor heat exchanger with one end of a refrigerant passage connected to the four-way switching valve 20, and the other end connected to the first expansion valve 23 and the first
A series line of the check valve 25, the second expansion valve 24 and the second
The refrigerant passages are connected in series to parallel refrigerant passages which are prevented from flowing in opposite directions by a series of check valves 26 . 22 is an indoor heat exchanger whose one end is connected to the parallel refrigerant passage, and the other end is connected to the four-way switching valve 2.
Connected to 0. A refrigerant pipe 27 is connected at one end to the opening 18, and the other end is connected to the indoor heat exchanger 22 and the four-way switching valve 20 via an on-off valve 28 such as a solenoid valve that constitutes a part of the unloading control means. It is connected to the indoor heat exchanger 22 side of the refrigerant pipe 29 that connects the refrigerant pipe 29 to the indoor heat exchanger 22 side. 30 is an outdoor blower, and 31 is an indoor blower.

Next, its effect will be explained. Electric motor 3 (Fig. 1)
The crankshaft 4 is rotated by the drive of the rotating scroll 6 by the crankshaft 4 and the rotation prevention mechanism 8.
performs a differential movement with respect to the fixed scroll 5 (see FIG. 2). This movement creates a space (compression chamber)
As 5a moves toward the center of the scroll, its space volume decreases, and the refrigerant gas sucked in from the suction pipe 11 is compressed and discharged from the discharge pipe 13 (FIG. 1). The discharged high-pressure high-temperature refrigerant gas flows through the discharge pipe 19a (FIG. 4), and in the case of a cooling cycle, flows through the dotted line passage of the four-way switching valve 20 according to the dotted line arrow and flows into the outdoor heat exchanger 21. .
Inside the outdoor heat exchanger 21, heat is exchanged with outside air forcedly ventilated by the outdoor blower 30, and the air is condensed and liquefied. The liquefied refrigerant passes through the second check valve 26, is depressurized and expanded in the second expansion valve 24, flows into the indoor heat exchanger 22, exchanges heat with indoor air forcedly ventilated by the indoor blower 31, and performs a cooling effect. Let's do it. Next, the low-temperature refrigerant flows through the four-way switching valve 20 via the refrigerant pipe 29,
The scroll compressor 1 flows through the suction pipe 19b.
Inhaled again at 9. In the above driving process,
A backflow limiting valve 1 that gives an instruction to open a solenoid valve 28 when unloading operation is required due to a decrease in load.
Since the spring 17b of No. 7 always acts in the direction of opening the valve portion 17a, when the on-off valve 28 such as the solenoid valve is opened, a part of the refrigerant in the space (compression chamber) 5a passes through the gap 17g to the low pressure side. leak. Therefore, the discharge amount decreases and becomes a discharge amount commensurate with the load, allowing appropriate unloading operation.
When the on-off valve 28, such as a solenoid valve, is closed, normal operation with 100% load is achieved. The above-mentioned devices are particularly effective when used in cooling-only machines. In FIG. 4, heating operation can be performed by switching the four-way switching valve 20 and flowing the discharged refrigerant gas in the direction of the solid arrow. In this case, the discharged high-pressure and high-temperature refrigerant gas passes through the four-way switching valve 20, and then passes through the indoor heat exchanger 22, the first check valve 25, the first expansion valve 23, and the outdoor heat exchanger 2.
1 and the four-way switching valve 20 in this order, and is sucked into the scroll compressor 19 again. In this operation, the on-off valve 28 is kept closed. Even if it is left open, the valve portion 17a will end up being closed by the high-pressure refrigerant gas. From the above, it can be seen that the backflow restriction valve 17 shown in FIG. 3 is effective during cooling operation.

5 to 8 are partial explanatory diagrams of the present invention.

Reference numeral 32 designates a backflow limiting valve that is a part of the injection control means and has a structure different from that of the backflow limiting valve 17 described above.

This backflow restriction valve 32 has valve portions 32a and 3 at both ends.
2b, and a connecting pipe 33 is provided at the end of the valve portion 32a. Further, an opening 34 connected to a refrigerant passage of a refrigeration cycle is connected to the tip of the valve portion 32b. A spring 35 acts to always close the valve portion 32b on the opening 34 side. 3
Reference numeral 6 denotes a small hole that penetrates the valve body 37. This backflow restriction valve 32 is connected to a refrigeration cycle shown in FIG. In FIG. 6, the same parts as in FIG. 4 are represented by the same reference numerals, and their explanations are omitted. The connecting pipe 33 of the backflow restriction valve 32 is connected to the scroll compressor 1
It is connected so as to communicate with the hole 15 of the fixed scroll 5 of No. 9. On the other hand, the opening 34 is connected to the indoor heat exchanger 22 through a refrigerant pipe 38 and an on-off valve 39 such as a solenoid valve that constitutes a part of the injection control means.
It is connected to a refrigerant pipe 40 between the second expansion valve 24 and the first check valve 25 .

In the refrigerant cycle shown in FIG. 6, the refrigerant gas compressed by the scroll compressor 19 passes through the four-way switching valve 20, the indoor heat exchanger 22, the first check valve 25, and the first It passes through the expansion valve 23, the outdoor heat exchanger 21, and the four-way switching valve 20 in the direction of the solid arrow, and returns to the scroll compressor 19 again. In the above operation process, when the on-off valve 39 is opened, high-pressure liquid refrigerant flows from the refrigerant pipe 38 into the backflow restriction valve 32 and acts on the valve portion 32b. Since the liquid refrigerant has a high pressure, it acts by overcoming the spring 35 and closes the valve portion 32a on the opposite side. However, some of the liquid refrigerant flows through the pores 36 to the scroll compressor 19.
Inject into the space (compression chamber). and,
It is compressed together with the low-pressure refrigerant drawn in from the suction side and then discharged. Therefore, the heating capacity improves by the amount injected. If the on-off valve 39 is closed and the machine is operated, it will be in a normal operating state in which the performance does not increase.

In addition, during cooling operation, the refrigerant flows in the direction of the dotted arrow, passing through the four-way switching valve 20, the indoor heat exchanger 21,
It flows through the second check valve, the second expansion valve, the indoor heat exchanger 22 and the four-way switching valve 20 in this order. In this case, even if the on-off valve 39 is opened, low-pressure refrigerant gas acts on the backflow restriction valve 32, so the valve portion 32b is closed by the force of the spring 35. Therefore, it can be seen that the backflow restriction valve 32 shown in FIG. 5 is effective when used during heating operation.

In addition, in the backflow restriction valve 17 shown in FIG. 3, the pore 3 like the backflow restriction valve 32 shown in FIG.
6 is installed on the valve stem 17d of the backflow restriction valve 17, and the connecting pipe 18 is connected to the refrigerant pipe 40 between the outdoor heat exchanger 22 and the second expansion valve 24 or the first check valve 25, as shown in FIG. It is also understood that the same control as when using the backflow restriction valve 32 shown in FIG.

Each of the above-described backflow restriction valves 17 and 32 can also be housed inside the closed container 1.

As mentioned above, the backflow restriction valve 17 shown in FIG. 3 is suitable for a cooling-only machine, and the backflow restriction valve 32 shown in FIG. 5 is suitable for a heating-only machine. However, this effect is produced not only by the structure of the valve but also by the structure of the connecting piping.

FIG. 8 shows a refrigeration cycle in an embodiment of the refrigeration apparatus of the present invention. This refrigeration cycle has a configuration that combines the cycle shown in FIG. 4 and the cycle shown in FIG. .

Since the present invention is configured as described above, the capacity can be increased by injection during heating operation, and unloading operation is possible during cooling operation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a scroll compressor which is one of the components of an embodiment of the present invention, and FIG. 2 is a sectional view of the scroll tooth portion. Fig. 3 is a sectional view of a backflow restriction valve in an embodiment of the present invention, Fig. 4 is a refrigeration cycle piping diagram, Fig. 5 is a sectional view of a backflow restriction valve in the above embodiment, and Fig. 6 is a refrigeration cycle piping diagram. , FIG. 7 is a sectional view taken along the line AA in FIG. 5, and FIG. 8 is a refrigeration cycle diagram in one embodiment of the present invention. 1... Airtight container, 2... Scroll compressor section,
3...Electric motor section, 4...Crankshaft, 5...Fixed scroll, 6...Orbiting scroll, 7...Frame, 11...Suction pipe, 12...Discharge port, 13...
...Discharge piping, 17... Backflow restriction valve, 18... Connection pipe, 19... Scroll compressor, 20... Four-way switching valve, 21... Outdoor heat exchanger, 22... Indoor heat exchanger, 23... 1st expansion valve, 24...2nd expansion valve, 25...1st check valve, 26...2nd check valve,
27...Refrigerant piping, 28...Opening/closing valve, 29...Refrigerant piping, 30...Outdoor blower, 31...Indoor blower, 32...Backflow restriction valve.

Claims (1)

[Scope of Claims] 1. A four-way switching valve connected to the suction side and discharge side of the scroll compressor, one side of the outdoor heat exchanger, and one side of the indoor heat exchanger, and the other side of the outdoor heat exchanger and A first check valve and a first expansion valve are arranged in series in a refrigerant pipe connected to the other side of the indoor heat exchanger, and a second check valve and a second expansion valve are arranged in parallel. A refrigeration cycle is constructed in which a first check valve and a second check valve are arranged so as to stop the flow in opposite directions to each other, and a cooling operation and a heating operation can be performed by switching the four-way switching valve. When the load decreases during cooling operation between the refrigerant piping connected to the four-way switching valve of the refrigeration cycle and one side of the indoor heat exchanger and the compression chamber of the scroll compressor, the compression chamber of the scroll compressor decreases. A part of the high-pressure refrigerant of the scroll compressor is provided between the other side of the indoor heat exchanger and the compression chamber of the scroll compressor, and a part of the high-pressure refrigerant of the scroll compressor is disposed between the other side of the indoor heat exchanger and the compression chamber of the scroll compressor. A refrigeration system comprising injection control means for injecting high-pressure refrigerant from the other side of the indoor heat exchanger into the compression chamber when it is necessary to increase the suction amount of the refrigerator. 2 The unloading control means includes at least an opening on the compression chamber side connected to the compression chamber of the scroll compressor, an opening on the refrigerant pipe side connected to one side of the indoor heat exchanger, and an opening on the compression chamber side. When the pressure at the refrigerant pipe side opening is higher than that at the refrigerant pipe side opening, the compression chamber side opening is opened and connected to the refrigerant pipe side opening,
2. The refrigeration system according to claim 1, further comprising a backflow limiting valve comprising a spring-loaded valve portion that closes the compression chamber side opening when the pressure in the refrigerant pipe side opening is higher than that in the compression chamber side opening. 3. The injection control means includes at least an opening on the compression chamber side of the scroll compressor, an opening on the other side of the indoor heat exchanger, and an opening on the other side of the indoor heat exchanger, and an opening on the other side of the indoor heat exchanger. When the pressure is higher, the compression chamber side opening is opened and the other side opening of the indoor heat exchanger is closed, and the pressure of the other side opening of the indoor heat exchanger is higher than that of the compression chamber side opening. At this time, the opening on the other side of the indoor heat exchanger is opened, the opening on the compression chamber side is closed, and a part of the liquid refrigerant is introduced into the compression chamber through the thin hole formed between the opening on the compression chamber side and the opening on the compression chamber side. 2. The refrigeration system according to claim 1, further comprising a backflow restriction valve comprising a spring-loaded valve portion that injects the air.