JPH0827083B2 - Refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigerating apparatus including a compressor with an unloader, and more particularly to a measure for preventing chattering of an unloader piston when switching refrigerating cycles.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 57-142183, as shown in FIG. 7, a compressor (cp) of a refrigeration system is used.
An unloader piston (a) which is arranged in a cylinder (c) provided therein and switches the compressor (cp) between an unload state and a full load state according to the back pressure, and an unloader piston (a) of the unloader piston (a). A high pressure supply passage (g) for connecting the back pressure chamber (b) and the discharge pipe (d) of the compressor (cp) via a pressure reducing mechanism (f) is provided, and high pressure is supplied via an on-off valve (h). An unload passage (g) that bypasses the refrigerant from the supply passage (g) to the suction side of the compressor (cp) is provided, and when the on-off valve (h) is turned off and closed, the unloader piston (a) spine is removed. High pressure is supplied to the pressure chamber (b), and the unloader piston (a) closes the bypass hole (i) against the urging force of the spring (s), so that the operating capacity of the compressor (cp) is maintained at the rated value. While it is in the full load state, turn on the on-off valve (h) When opened, the high pressure to be supplied to the back pressure chamber (b) of the unloader piston (a) is bypassed to the suction side of the compressor, the unloader piston (a)
Of the compressor (c) by moving the unloader piston (a) to open the bypass hole (i) by the urging force of the spring (s).
It is a known technique that the operating capacity of the compressor (cp) is controlled in two stages by setting the operating capacity of p) to the unload state, which is a predetermined ratio in the full load state.

(Problems to be Solved by the Invention) In the above-mentioned conventional apparatus, when the compressor (cp) is operated in a full load state, even when the refrigeration cycle is switched, for example, when performing a reverse cycle defrost operation, As shown in the figure, high pressure is supplied to the back pressure chamber (b) of the unloader piston (a) with the on-off valve (h) turned off and closed.

However, in that case, there are the following problems.
That is, as shown in FIG. 9, the discharge line and the suction line are rapidly switched at the start and end of the defrost operation, so that the high pressure decreases (see the solid line in the figure), while the low pressure increases. (Refer to the solid line in the figure) The difference almost disappears. Then, the back pressure of the unloader piston (a) decreases with a predetermined time delay with respect to the decrease of the high pressure (see the broken line in the figure), and urges the unloader piston (a) away from the bypass hole (i). The biasing force of the spring (s) and the back pressure are balanced and become unstable.
Therefore, there is a problem that so-called chattering occurs in which the unloader piston (a) vibrates due to a slight change in pressure. Also, such chattering has resulted in a loss of reliability of the compressor (cp).

The present invention has been made in view of the phenomenon that the back pressure of the unloader piston decreases with such switching of the refrigeration cycle, and that the decrease occurs with a predetermined time delay with respect to the decrease in high pressure. Is to effectively prevent chattering of the unloader piston by providing a means for stabilizing the position of the unloader piston in the cylinder at the time of switching the refrigeration cycle.

(Means for Solving the Problem) A first means for solving the problem in order to achieve the above object is to control the back pressure of the unloader piston at a low pressure for a predetermined time at the time of switching the refrigeration cycle.

Specifically, the first solution means, as shown in FIG. 1 (excluding the broken line portion), is directed to a refrigerating device having a main refrigerant circuit (9) configured to be able to switch refrigerating cycles.
And a compressor (1) arranged in the main refrigerant circuit (9)
The cylinder (46) is arranged on the discharge side of the cylinder, and the cylinder (46) is provided with a bypass hole (45) which opens a part of the compressed refrigerant to the suction side so as to be able to bypass the cylinder (46). A pressure space (46a) is formed, and when the back pressure space (46a) is in a high pressure state, the back pressure space (46a) is moved so as to be expanded to close the bypass hole (45) to close the compressor (1). While the back pressure space (46a) is in a low pressure state, the back pressure space (46a) is moved so as to reduce the bypass pressure space (46a).
An unloader piston (48) that opens 5) to switch the compressor (1) to an unloading state, and a spring (49) that biases the unloader piston (48) in the direction in which the back pressure space (46a) contracts. Set up. On the other hand, the discharge pipe (8a) of the compressor (1) is branched off to form an unloader piston (48).
High pressure supply passage (10) communicating with the back pressure space (46a) of the pressure reduction mechanism (13) through the three pressure reduction mechanisms (13), and the compressor (1) downstream of the pressure reduction mechanism (13) of the high pressure supply passage (10). Suction pipe (8b)
And an on-off valve (15) for opening and closing the unload passage (14) for bypassing high pressure to the intake side, and an opening / closing valve (15) for refrigerating the main refrigerant circuit (9). At the time of cycle switching, the high pressure from the high pressure supply passage (10) is introduced into the suction pipe (8b) of the compressor (1), and the back pressure space (46a)
A switching operation control means (61) forcibly opening the opening / closing valve (15) for a predetermined time is provided so as to suppress the introduction of high pressure into the structure.

A second solution is to prevent backflow of the back pressure of the unloader piston to the discharge side at the time of switching the refrigeration cycle, so that the back pressure of the unloader piston generated with a predetermined time delay from the decrease in the high pressure. It is to prevent the decline.

Specifically, as shown in FIG. 1 (excluding the dotted line portion), assuming a refrigeration system (excluding the switching operation control means (61)) having the same configuration as the first solving means, Prevents the flow of refrigerant to the discharge pipe (8a) side between the joint (P) of the high pressure supply passage (10) with the discharge pipe (8a) and the joint (Q) of the unload passage (14). The check valve (11) is provided.

A third solution means is that in the first or second solution means, the compressor (1) compresses the refrigerant by the scroll mechanism (31), and the bypass hole (45) is provided in the scroll mechanism (31). The structure is opened to the internal compression chamber (40).

(Operation) With the above configuration, in the invention of claim (1), the switching operation control means (61) is provided at the time of switching the refrigeration cycle of the refrigeration system.
As a result, the on-off valve (15) is forcibly opened and the back pressure of the unloader piston (48) is controlled so as to decrease to a low pressure level. Therefore, the unloader piston (48) is controlled by the biasing force of the spring (49). The bypass hole (45) is maintained in the open position for a while, and chattering of the unloader piston (48) is prevented.

According to the invention of claim (2), in the high pressure supply passage (10), the discharge pipe (P) is provided between the joint (P) with the discharge pipe (8a) and the joint (Q) with the unload passage (14). Since the check valve (11) for blocking the flow of the refrigerant to the 8a) side is provided, the unloader piston (48) is provided at the time of switching the refrigeration cycle.
Since the backflow of the high pressure supplied as the back pressure of the compressor to the discharge pipe (8a) side is blocked, even if the high pressure decreases on the discharge pipe (8a) side of the compressor (1), the unloader piston (48) The decrease in back pressure is suppressed, and chattering is prevented.

According to the invention of claim (3), in the invention of claim (1) or (2), when the compressor (1) is of a scroll type, due to its structure, the refrigerant pressure during the compression stroke. The back pressure of the unloader piston (48) is received by the unloader piston, and a state in which the urging force of the spring (49) and the back pressure are in balance tends to occur. By the action, chattering of the unloader piston (48) is prevented.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows the structure of the outdoor unit (A) of the air conditioner according to the first embodiment of the present invention.
The compressor (1), the oil separator (2) for separating the oil in the refrigerant discharged from the compressor (1), and the switching during the indoor cooling operation as shown by the solid line in the figure. , A four-way switching valve (3) that switches during heating operation as shown by the broken line in the figure,
An outdoor heat exchanger (4) that functions as a condenser during cooling operation and an evaporator during heating operation, an electronic expansion valve (5) that regulates the refrigerant flow rate during cooling operation, and reduces the refrigerant during heating operation, and a liquid refrigerant. A receiver (6) for accumulating water and an accumulator (7) for separating a liquid component in the suction refrigerant are arranged. Although not shown, the indoor unit includes an indoor heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, and an indoor side that reduces the refrigerant during cooling operation and adjusts the refrigerant flow rate during heating operation. An electronic expansion valve is arranged, each of the above devices is connected to a refrigerant pipe (8) so that the refrigerant can flow, and heat is transferred so that heat obtained by heat exchange with the outdoor air is applied to the indoor side. A refrigerant circuit (9) is constructed.

Then, a high pressure supply passage (10) connected to a bypass hole (45) in the compressor (1) described later from a joint (P) which is one point on the discharge pipe (8a) of the compressor (1). Is provided in a branched manner, and the high pressure supply passage (10) has a filter (12) and a capillary tube (13) as a pressure reducing mechanism.
And are sequentially provided from the above-mentioned joining portion (P). Also,
The capillary tube (13) in the high-pressure supply passage (10)
An unloading passage (14) for connecting the refrigerant to a suction pipe (8b) of the compressor (1) from a joint (Q) which is a point between the compressor and the compressor (1), The unload passage (14) is provided with an opening / closing valve (15) for opening and closing the unload passage (14).

Here, regarding the detailed structure of the compressor (1),
As will be described with reference to the drawings, the compressor (1) includes a scroll mechanism (31) for compressing a refrigerant in a closed casing (1a) to generate a high pressure state, and the scroll mechanism (31).
An unload mechanism (32) for switching the pressure state of the refrigerant discharged from the high pressure to an intermediate pressure which is a predetermined ratio of the high pressure is arranged.

The scroll mechanism (31) is a fixed scroll (33).
And a movable scroll (34). Each of the fixed scroll (33) and the movable scroll (34) has an end plate (3
Wraps (37) and (38) are erected vertically on one side of 5) and (36). Both scrolls (33) and (34) face the front faces of the end plates (35) and (36). And the laps (37) and (38) are meshed with each other. In the fixed scroll (33), a flange (35a) is continuously provided on the outer peripheral edge of the end plate (35) and is fixed to the casing (1a) by the flange (35a), and the inside of the casing (1a) is fixed scroll (33). ) It is divided into an upper high pressure chamber (1b) and a low pressure chamber (1c). Further, a scroll shaft (36a) is provided at the center of the rear surface of the end plate (36) of the movable scroll (34), and the movable scroll (34) fixes the fixed scroll (33) by the scroll shaft (36a). It is only possible to revolve against.

The wraps (37) and (38) of the fixed scroll (33) and the orbiting scroll (34) make multi-point contact (39) on their side faces, and the other scroll end plates (36) and (35) at their end faces. ) And contact (3
A closed chamber (40) is formed between 9). Also, the flange (35a) and the wrap (37) of the fixed scroll (33).
And a discharge port (42) is formed in a substantially central portion of the end plate (35), and a low pressure is applied from the suction port (41). The refrigerant gas is supplied to the closed chamber (40), and the high pressure refrigerant gas is discharged from the closed chamber (40) into the high pressure chamber (1b) through the discharge port (42). In addition, (43) is a discharge pipe joint that connects the high pressure chamber (1b) of the compressor (1) and the discharge pipe (8a), (44) is a demister for removing oil in the discharge refrigerant, (44a) Is a demister cover that holds the demister (44).

Next, the unloader mechanism (32) is used as a main device.
A cylindrical cylinder (46) having a central axis in the up-down direction, which is arranged at an intermediate position of the fixed scroll (33), and the fixed scroll (33) and the movable scroll (34) at the end surface of the cylinder (46). Closed chamber (40) between both wraps (37), (38)
A bypass hole (45) opening to the cylinder, a bypass passage (47) provided obliquely below the cylinder of the cylinder (46) for bypassing the refrigerant to the low pressure chamber (1c), and a cylinder (4).
6) It is slidable up and down in the inside, and the upper part is wound around a large diameter stepped cylindrical unloader piston (48) and around the small diameter part of the unloader piston (48) in the cylinder (46). , A spring (49) for urging the unloader piston (48) upward, and a spring (49) provided above the cylinder (46), which is installed in the back pressure chamber (46a) of the cylinder (46) from the high pressure supply passage (10). An unloader lid assembly member (50) having an introduction passage (10a) for introducing high pressure, and the unloader assembly member (5)
0), which is fitted into the upper part of the unloader operating pipe (51) and has a bottom open, and a cylindrical unloader operating pipe (51) with a bottom, and the unloader operating pipe (51) which is horizontally attached to the upper side of the unloader operating pipe (51).
And a gauge joint (52) with a check valve, which connects the cylinder part (51a) and the high-pressure supply passage (10) so that the refrigerant can flow therethrough.

That is, when the on-off valve (15) is turned off and closed, the discharge pressure from the compressor (1) remains in the unload mechanism (32) via the high-pressure supply passage (10) and the introduction passage (10a). As a result of being introduced into the back pressure chamber (46a) of the cylinder (46), the unloader piston (48) moves downward against the urging force of the spring (49) to close the bypass hole (45), When the on-off valve (15) is turned on and opened, high pressure is bypassed to the suction side through the unload passage (14), and as a result, the back of the unloader piston (48) supplied from the high pressure supply passage (10). The pressure decreases, the unloader piston (48) moves upward by the urging force of the spring (49), and the bypass hole (45) opens.

As shown in FIG. 4A or 4B, the bypass hole (45), the cylinder (46), the bypass passage (47), the unloader piston (48) and the spring (49) are all scrolls (33). , (34) two closed chambers (40), (40)
It is provided in two places corresponding to.

When the bypass hole (45) is closed,
As shown in FIG. 4A, the sealed chambers (40) between the scrolls (33) and (34), the wraps (37), and (38) are all in the final discharge state during the revolution of the movable scroll (34). By maintaining the sealed state up to this point, the high pressure compressed in the entire stroke is discharged from the compressor (1), but when the bypass hole (45) is opened, as shown in FIG. 4B, the movable scroll ( Since the sealed state is broken up to the intermediate stroke of 34), only the refrigerant compressed from the intermediate stroke to the final stroke is discharged, and the high pressure of the compressor (1) is reduced to a predetermined value (50%). Will be.

In addition, in FIG. 2, (Hps) is arranged in the discharge pipe (8a), a high pressure switch for stopping the compressor (1) when the high pressure rises excessively, (Lps) in the suction pipe (8b). Placed,
A low pressure switch for stopping the compressor (1) when the low pressure falls excessively, (Ps) is arranged in the discharge pipe (8a),
Before the discharge pressure reaches the over-rise value at which the high pressure switch (Hps) operates, the open / close valve (15) is opened to keep the compressor (1) in the unload state and the outdoor fan (4a) is turned on. It is a pressure switch for switching from a high air volume to a low air volume during a heating operation and from a low air volume to a high air volume during a cooling operation.

Here, as a feature of the present invention, for example, when the compressor (1) is operated in a full load state during heating operation, when defrost operation or oil recovery operation is started, or when defrost operation or oil recovery operation is completed, At the time of cycle switching such as switching to operation, as shown in FIG. 5, forcibly open the on-off valve (15) for a predetermined time n seconds (n is, for example, about 30 seconds), that is, The back pressure of the unloader piston (48) of the unloader mechanism (32) is reduced to a low pressure level. That is,
It is avoided that the high pressure in the discharge pipe (8a) decreases and the back pressure of the unloader piston (48) balances with the urging force of the spring (49) as the cooling and heating cycle is switched, and the back pressure is further reduced. By lowering it to the level, the unloader piston (48) is held in the upper unload position by the urging force of the spring (49). By the above control, the switching operation control means (61) is configured to control the opening / closing valve (15) to be forcibly opened for a predetermined time when the refrigeration cycle of the main refrigerant circuit (9) is switched.

Therefore, in the invention of claim (1), for example, at the time of cycle switching such as the start or end of the reverse cycle defrost operation, the switching operation control means (61) forces the on-off valve (15) for a predetermined time. It is opened and the back pressure of the unloader piston (48) is controlled to drop to a low pressure level.

Here, as in the prior art, in the case where the open / close valve (15) is closed and the full load state is maintained as it is even at the time of cycle switching, the high pressure is reduced due to the cycle switching as shown in FIG. In the load mechanism (32), the back pressure of the unloader piston (48) decreases, and the upward biasing force of the spring (49) and the unloader piston (4)
8) It becomes an unstable state that balances with the back pressure. Moreover, the unloader piston (48) has two scrolls (33),
Since upward pressure is applied by the pressure from the closed chamber (40) in the compression stroke by (34), the height of the unloader piston (48) reverses due to slight changes in the pressure state during the compression stroke. Chattering may occur.

On the other hand, in the present invention, the switching operation control means (61) opens the on-off valve (15) as shown in FIG. 5 during the predetermined time during cycle switching, and the unloader piston (48).
Since the back pressure of the cylinder is controlled so as to be reduced to a low pressure level, the unloader piston (48) is positioned above the cylinder (46) for a predetermined time by the biasing force of the spring (49). Such chattering of the unloader piston (48) can be effectively prevented.

Next, a second embodiment according to the invention of claim (2) will be described. FIG. 6 shows the configuration of the air conditioner according to the second embodiment, (11) is the discharge pipe (8a) of the high-pressure supply passage (10).
The check valve is provided between the joint (P) and the filter (12) and prevents the refrigerant from flowing to the discharge pipe (8a) side. That is, even when the high pressure drops during cycle switching, etc., the discharge pipe (8a) is fed from the high pressure supply passage (10) side.
The refrigerant does not flow backward to the side and the back pressure of the unloader piston (48) in the compressor (1) does not decrease. The other configurations are the same as those in the first embodiment.

Therefore, in the invention of claim (2), in the high pressure supply passage (10), the discharge is performed between the joint (P) with the discharge pipe (8a) and the joint (Q) with the unload passage (14). Tube (8
Since the check valve (11) for blocking the flow of the refrigerant to the a) side is provided, when the cycle is switched such as when the reverse cycle defrost operation is started or stopped, as shown by the solid line in FIG. The high pressure in the discharge pipe (8a) of the machine (1) momentarily drops, but the check valve (11) prevents the high pressure supplied to the unloader piston (48) from flowing back to the discharge pipe (8a) side. Therefore, the back pressure of the unloader piston (48) decreases with a predetermined time delay with respect to the decrease in high pressure in the discharge pipe (8a) as in the conventional case (see the broken line in the figure).
Will be suppressed. Therefore, it is possible to prevent chattering of the unloader piston (48).

According to the invention of claim (3), in the invention of claim (1) or (2), when the compressor (1) is provided with the scroll mechanism (31) as in each of the above-mentioned embodiments, its structure is high. , Due to the reaction force against the back pressure of the unloader piston (48) due to the refrigerant pressure during the compression stroke, the chattering of the unloader piston (48) is likely to occur due to the pressure change during the compression stroke. In such cases,
In the present invention, the chattering of the unloader piston (48) can be prevented by the effect of the invention of the above-mentioned claim (1) or (2).

In each of the above-described embodiments, the scroll type compressor is used as the structure of the compressor (1), but the present invention can be similarly applied to a normal reciprocating compressor. There is no end.

(Effect of the invention) As described above, according to the invention of claim (1),
A bypass hole that bypasses part of the discharged refrigerant is provided inside the compressor, and the bypass hole is opened and closed by the movement of the unloader piston that is urged by the spring in the direction to open the bypass hole. While being configured to switch to the load state, a high pressure supply passage that bypasses the discharge pipe is provided, high pressure is introduced as a back pressure by the unloader piston, and an unload passage is provided from the high pressure supply passage to the suction pipe through an on-off valve. When the on-off valve is closed, the back pressure of the unloader piston is made high to maintain the compressor in the full load state, while when the on-off valve is opened, the back pressure of the unloader piston is made low to unload the compressor. In this way, when switching the refrigeration cycle, the on-off valve is forcibly opened for a predetermined time. Chattering can be prevented effectively reduced by the unloader piston by the balance between the back pressure of the biasing force and unloader piston spring.

According to the invention of claim (2), in the refrigerating apparatus having the same configuration as that of the invention of claim (1), between the joint of the high pressure supply passage with the discharge pipe and the joint of the unload passage. Since a check valve was installed to block the flow of refrigerant to the discharge pipe side, when the refrigeration cycle was switched, the back pressure of the unloader piston returned to the discharge pipe via the high pressure supply passage due to the decrease in high pressure, and the unloader piston It is possible to prevent the back pressure from decreasing, and thus to prevent chattering due to the balance between the back pressure of the unloader piston and the urging force of the spring.

According to the invention of claim (3), in the invention of claim (1) or (2), when the compressor is constituted by a scroll mechanism, the compression of the refrigerant from the closed chamber of the scroll mechanism. Chattering of the unloader piston is likely to occur due to the change in force, but the effect of the invention of the above-mentioned claim (1) or (2) can prevent chattering.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 5 show the first embodiment of the present invention, FIG. 2 is a refrigerant piping system diagram showing the overall configuration of the air conditioner, and FIG. 3 is a portion showing the internal structure of a scroll type compressor. Longitudinal section,
FIG. 4A and FIG. 4B are internal cutaway views of the scroll for explaining the difference in compression stroke between the full load state and the unload state of the unloader mechanism of the compressor, and FIG. 5 is the opening and closing of the open / close valve when switching the refrigeration cycle. FIG. 6 is a refrigerant pipe system diagram showing the configuration of the air conditioner according to the second embodiment. 7 to 9 show a conventional technique, FIG. 7 is a partial cross-sectional view showing a configuration example of an unloader mechanism, FIG. 8 is a time chart diagram showing opening / closing of an on-off valve, and FIG. 9 is switching of refrigeration cycle. FIG. 6 is a characteristic diagram showing changes in high pressure and low pressure, and changes in back pressure of the unloading piston. 1 ... Compressor 8a ... Discharge pipe 8b ... Suction pipe 9 ... Main refrigerant circuit 10 ... High pressure supply circuit 11 ... Check valve 13 ... Capillary tube (pressure reducing mechanism) 14 ... Unload passage 15 ... … Open / close valve 31 …… Scroll mechanism 32 …… Unloader mechanism 45 …… Bypass hole 46 …… Cylinder 48 …… Unloader piston 49 …… Spring 61 …… Switching operation control means P, Q …… Joining section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimasa Doi 3-12, Chikko Shinmachi, Sakai City, Osaka Prefecture Daikin Industrial Co., Ltd. Sakai Plant's seaside factory (56) Reference JP 62-17572 (JP, A) Special Kai 60-159566 (JP, A) JP 54-23238 (JP, A)

Claims (3)

[Claims] 1. A refrigeration system having a main refrigerant circuit (9) configured to be capable of switching refrigeration cycles, wherein a cylinder (46) is provided on the discharge side of a compressor (1) arranged in the main refrigerant circuit (9). A back pressure space (46a) is formed between the cylinder (46) and a bypass hole (45) that opens a part of the compressed refrigerant to the suction side so as to be able to bypass the cylinder (46). When the back pressure space (46a) is in a high pressure state, the back pressure space (46a)
While the compressor is moving to expand the valve to close the bypass hole (45) and put the compressor (1) into a full load state, while the back pressure space (46a) is in a low pressure state, the back pressure space (46a) is closed. An unloader piston (48) that moves so as to reduce and opens the bypass hole (45) to switch the compressor (1) to an unloading state, and a direction in which the unloader piston (48) reduces the back pressure space (46a). While the spring (49) for urging the compressor (1) is provided, the pressure reducing mechanism (1) is branched from the discharge pipe (8a) of the compressor (1) into the back pressure space (46a) of the unloader piston (48).
And a high pressure supply passage (10) communicating with each other via a high pressure supply passage (10), which is provided between the high pressure supply passage (10) downstream of the pressure reducing mechanism (13) and the suction pipe (8b) of the compressor (1). , An unload passage (14) for bypassing the high pressure to the suction side, an opening / closing valve (15) for opening and closing the unload passage (14), and a high pressure supply when the refrigeration cycle of the main refrigerant circuit (9) is switched. The on-off valve (for a predetermined time) is introduced for a predetermined time so that high pressure from the passage (10) is introduced into the suction pipe (8b) of the compressor (1) to suppress introduction of high pressure into the back pressure space (46a). A refrigeration system comprising: a switching operation control means (61) for forcibly opening 15). 2. A refrigeration system having a main refrigerant circuit (9) configured to be capable of switching refrigeration cycles, wherein a cylinder (46) is arranged on the discharge side of a compressor (1) arranged in the main refrigerant circuit (9). And a bypass hole (45) for opening a part of the discharged refrigerant to the suction side in the cylinder (46) so that the refrigerant can be bypassed.
When the back pressure is high, the bypass hole (45) is closed to put the compressor (1) in a full load state, while when the back pressure is low, the bypass hole (45) is opened to unload the compressor (1). Unloader piston (48) for switching to a state and a spring (4) for urging the unloader piston (48) toward the back pressure side.
9) and a high pressure supply passage (10) branching from the discharge pipe (8a) of the compressor (1) and communicating with the back pressure side of the unloader piston (48) via the pressure reducing mechanism (13). , The high pressure supply passage (10)
An unload passage (14) provided between the downstream side of the pressure reducing mechanism (13) and the suction pipe (8b) of the compressor (1) for bypassing high pressure to the suction side, and the unload passage. (1
Open / close valve (15) for opening / closing 4) and the high pressure supply passage (1)
Check valve for blocking the flow of the refrigerant toward the discharge pipe (8a) between the joint (P) with the discharge pipe (8a) and the joint (Q) with the unload passage (14). (11) A refrigeration system comprising: 3. A compressor (1) compresses a refrigerant by a scroll mechanism (31), and a bypass hole (45) is opened to a compression chamber (40) inside the scroll mechanism (31). The refrigerating apparatus according to claim 1, wherein the refrigerating apparatus is a refrigerator.