JPH0810085B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention includes an oil recovery device on the discharge side of a compressor, and cools the oil recovered by the oil recovery device with an oil cooler and returns it to the compressor. The present invention relates to the refrigerating apparatus, and more specifically, to a countermeasure against a high level abnormality of the oil level in the oil recovery device.

(Prior Art) Conventionally, as a countermeasure plan at the time of high level in this seed oil recovery device, the one disclosed in JP-A-2-183766 is known. When a high level is detected in the oil recovery unit, this type closes the motor-operated valve that constitutes the expansion mechanism of the refrigeration system for a predetermined time to extremely reduce the amount of intake gas sucked into the compressor, I run out of gas on the machine,
Forcibly raise the temperature of the discharge gas, reduce the amount of refrigerant gas that dissolves in the oil, reduce the volume of oil accumulated in the oil recovery unit,
It is designed to lower the oil level. In this way, avoiding high-level abnormalities is to prevent oil from accumulating in the condenser, evaporator, etc. installed downstream of the oil recovery unit, and to prevent the oil recovery unit and compressor from being sucked. This is for the purpose of preventing a large amount of oil from being transferred to the suction side of the compressor at the time of operation stop and causing oil compression at the time of restart, through a pressure equalizing pipe generally interposed between the side and the side.

(Problems to be Solved by the Invention) However, in the measures described in the above publication, the time loss of stopping and restarting the compressor can be saved as compared with the one in which the compressor is immediately stopped at the time of a high level abnormality, and the evaporator is used. Although it is possible to reduce the temperature fluctuations of the generated cold water, etc., since the amount of suction gas sucked into the compressor, that is, the amount of refrigerant passing through the evaporator is extremely reduced, the cooling capacity in the evaporator is almost lost, Eventually, there arises a problem that the temperature of cold water or the like generated in the evaporator fluctuates.

An object of the present invention is to avoid a high level abnormality in an oil recovery device while being able to almost eliminate the disturbance of the temperature distribution in the secondary device such as an evaporator without changing the circulation amount of the refrigerant. It is to provide a refrigerating device that can be used.

(Means for Solving the Problem) Therefore, in the present invention, in order to achieve the above object, an oil recovery device (2) is provided in the discharge path of the compressor (1), and the oil recovery device (2) is provided with an oil recovery device. A refrigeration system in which an oil cooler (4) is provided in an oil return path (3) connecting an outflow port and an oil injection port of the compressor (1), wherein the oil cooler is provided in the oil return path (3). A bypass passage (5) for bypassing a part of the oil passage in (4) is provided, and an opening / closing means (6) for opening and closing the bypass passage (5) and the height of the oil accumulated in the oil recovery unit (2). High level detection means (7) for detecting the level limit value,
An opening / closing control means (8) for controlling the opening / closing means (6) to open for a predetermined time when a high level is detected by the detection means (7) is provided.

Further, in the above structure, a bypass passage (50) that bypasses the oil cooler (4) is provided in place of the bypass passage (5) that bypasses a part of the oil passage in the oil cooler (4).

Furthermore, in order to ensure the safety of the refrigerating apparatus in each of the above-mentioned configurations, the compressor is controlled when the high level is re-detected by the high level detecting means (7) after the opening / closing means (6) is open controlled for a predetermined time. An operation stopping means (9) for stopping (1) is provided.

(Operation) When the high level of the oil recovery device (2) is detected by the high level detection means (7), the opening / closing means (6) is opened by the opening / closing control means (8) and the bypass passage (5) is opened. The oil returned from the oil collector (2) to the compressor (1) is the oil cooler (4).
The oil will flow by bypassing a part of the oil passage in. This reduces the pressure loss in the oil cooler (4),
The amount of the return oil increases, the oil level in the oil recovery unit (2) can be promoted to decrease, and the cooling area in the oil cooler (4) decreases, so the temperature of the return oil increases and The amount of the refrigerant gas that dissolves in the oil recovery unit (2) can be reduced, the volume of oil accumulated in the oil recovery unit (2) can be reduced, and the oil level in the oil recovery unit (2) can be reduced. Moreover, at this time, since the compressor (1) does not stop and the refrigerant circulation amount hardly changes, the temperature fluctuation in the secondary side device such as the evaporator can be almost eliminated.

When a bypass passage (50) that bypasses the oil cooler (4) is provided instead of the bypass passage (5) that bypasses a part of the oil passage of the oil cooler (4), an oil recovery device is used. At the high level in (2), the oil returns from the two paths of the bypass passage (50) and the oil cooler (4), so that the amount of return oil can be increased, and the oil in the oil recovery unit (2) can be increased. In addition to promoting the reduction of the surface, the oil that does not pass through the oil cooler (4) returns to the compressor (1), so the temperature of the return oil rises and the amount of refrigerant gas that dissolves in the oil can be reduced, and the oil recovery The volume of oil accumulated in the vessel (2) can be reduced, and the oil level in the oil recovery vessel (2) can be lowered.

Further, the operation stop control of the compressor (1) by the operation stop means (9) makes it possible to ensure the safety of the device when a high level abnormality that cannot be corrected by the bypass control occurs.

(Embodiment) The refrigerating apparatus shown in FIG. 1 comprises a screw type compressor (1) driven by a motor (10), and the compressor (1)
From the discharge side of the oil collector (2), which is directly connected to the oil separator (21) having the demister (20) and the oil tank (22), the water-cooled condenser (30) with the cooling water pipe (31), Expansion mechanism (35) and cold water withdrawal pipe (51) consisting of motor-operated valves and temperature-sensitive expansion valves
The evaporator (52) in which the pipe is connected is sequentially connected. Further, an oil cooler (4) is provided in an oil return path (3) connecting the oil outlet (23) of the oil collector (2) and the oil inlet (11) of the compressor (1), The compressor (1) is provided with good lubrication and sealing. Further, a pressure equalizing pipe (13) having an opening / closing valve (12) opened when the compressor is stopped is provided between the upper part of the oil recovery unit (2) and the suction side of the compressor (1). .

In the oil cooler (4), a large number of partition bodies (41) are arranged in a staggered manner in the jacket (40), and the oil cooler (4) has a meandering shape between the oil introduction port (42) and the oil removal port (43). An oil passage (44) is formed, and the oil passage (44) flows between the first header (46) to which the water pipe (45) is connected and the second header (47) on the other side. It has a cooling pipe (48) for cooling oil.

 Incidentally, (14) and (15) are check valves.

With the above configuration, the oil passage (4
An intermediate outlet (49) for taking out the oil flowing in 4) is provided on the way, and the latter half of the oil passage (44) is located between the intermediate outlet (49) and the oil return path (3). A bypass passage (5) is provided, and in the bypass passage (5),
An opening / closing means (6) composed of a solenoid valve (SV1) for opening / closing the bypass passage (5) is provided.

High level detection means (7) for detecting the high level limit value of the oil accumulated in the oil recovery device (2) in the oil recovery device (2).
And a low level detecting means for detecting a low level limit value (70)
Are provided.

Further, there is provided an opening / closing control means (8) for controlling the opening / closing means (6) to open for a predetermined time of about several tens of seconds when the high level is detected by the height level detecting means (7), and the opening / closing means is also provided. After the control means (8) controls the opening / closing means (6) to open for a predetermined time, when the high level is re-detected by the high level detecting means (7), the compressor (1)
An operation stopping means (9) for stopping the operation is provided. The low level detecting means (70) stops the compressor (1) immediately when a low level is detected.

The opening / closing control means (8) and the operation stop means (9)
Is composed of the electric circuit shown in FIG. 2, and its operation and action will be described below with reference to the flow chart shown in FIG.

During normal operation, the main power contact (27) is on and the cold water thermostat (23W) installed in the cold water extraction pipe (51)
E) and the interlock contact points (AXP) of the water circulation pump of the cold water extraction pipe (51) and the cooling water pipe (31) are all turned on, and the motor (10) of the compressor (1) is started and stopped. The relay (CM) is excited and its make contact (CM-
a1) (CM-a2) is turned on. Also, solenoid valve (SV1)
Is de-energized and the valve is closed (step in FIG. 3).

In this state, when the high level is detected by the high level detecting means (7) (step), the high level contact (330H) is turned on to excite the relay (330HX), and its make contact (3
30HX-a1) (330HX-a2) are turned on, and the first and second timers (T1) (T2) are excited. Here, the time limit of the first timer (T1) is set to, for example, 5 seconds, and the time limit of the second timer (T2) is set to, for example, 35 seconds, which is longer than that.

Thus, when the excitation of the first timer (T1) is continued for 5 seconds after the high level contact (330H) is turned on (step), the timed make contact (T1-a) is turned on and the solenoid valve ( SV1) is excited and the bypass passage (5) is opened (step). When the high-level contact (330H) is turned on and excitation of the second timer (T2) is continued for 35 seconds (step), the timed break contact (T2-b) is turned off and the solenoid valve ( SV1) is de-energized and the bypass passage (5) is closed (step). If the high level contact (330H) is turned off within 5 seconds after the first timer (T1) is excited, the solenoid valve (SV1) is not excited and the valve is not opened. This is because the case where the oil level rises extremely temporarily is excluded from the target of bypass control, and at the same time, reliable high level detection is performed. or,
Even if the solenoid valve (SV1) is once energized by the first timer (T1) and the valve is opened, if the high-level contact (330H) is turned off within 35 seconds, the process returns from step to the solenoid valve (SV1). ) Is de-energized at that point and closed. This is because the oil level falls below the high level limit and the need for bypass control is eliminated.

From the above, when a high level is detected, the bypass passage (5) is opened for a maximum of 30 seconds, and by this bypass control, most of the return oil passing through the oil cooler (4) is in the oil passage. Without passing through the latter half part of (44), it is withdrawn from the intermediate outlet (49) and returned to the compressor (1). For this reason, the pressure loss in the oil cooler (4) is reduced, the amount of return oil is increased, the oil level in the oil recovery device (2) can be promoted, and the oil cooler (4) can be used. Since the cooling area of the oil is reduced, the temperature of the return oil rises, the amount of the refrigerant gas dissolved in the oil can be reduced, and the volume of the oil accumulated in the oil recovery unit (2) can be reduced. The oil level in 2) can be lowered rapidly. Moreover,
At this time, the compressor (1) does not stop, and the circulation amount of the refrigerant flowing through the evaporator (52) hardly changes, so that there is almost no fluctuation in the temperature of the cold water generated in the evaporator (52). Can be done.

On the other hand, when the high level contact (330H) is turned on, the second timer (T2) continues to be excited for 35 seconds and bypass control is performed for a maximum of 30 seconds, but the high level does not disappear (step). The timed make contact (T2-a) of the second timer (T2) is turned on, and further, for example, 5
The third timer (T3) with a time limit of seconds is excited, and when the excitation is continued for 5 seconds (step), the time changeover contact (T3-c) is changed over and the timer relay (5T) is de-excited. Then, the break contact (5T-b) is returned from the off state to the on state, the relay (5X) is excited, and the break contact (5X-b) is turned off.
The relay (CM) that starts and stops the motor (10) of the compressor (1) is de-energized, and the operation of the compressor (1) is stopped (step).

At the same time, by switching the time limit switching contact (T3-c) of the third timer (T3), the self-holding relay (330H
Z) is excited, its make contact (330HZ-a) is turned on, the alarm lamp (OL1) is turned on, and the high level abnormality of the oil level is warned. (3R) is a reset switch that turns off the lamp.

By the above operation stop control of the compressor (1), the safety of the refrigeration system can be achieved when a high level abnormality that cannot be corrected by the bypass control occurs.

By the way, in the embodiment shown in FIG. 1, the bypass passage (5) is provided so as to bypass a part of the oil cooler (4), but as shown in FIG. A bypass passage (50) may be provided to bypass 4). In this case, it is preferable that the bypass passage (50) is made of a thin tube or the like so that part of the return oil passes through the oil cooler (4) so that the temperature of the return oil does not rise abnormally.

Also in this case, the control shown in FIG. 2 and FIG. 3 is performed when the oil recovery device (2) is at a high level, and there are two paths, the bypass passage (50) and the oil cooler (4). Since the oil is returned from the oil, the amount of the return oil can be increased, the lowering of the oil level in the oil recovery device (2) can be promoted, and the oil that does not pass through the oil cooler (4) returns to the compressor (1). Therefore, the temperature of the return oil rises, the amount of refrigerant gas dissolved in the oil can be reduced, and the volume of oil accumulated in the oil recovery device (2) can be reduced, and the oil level in the oil recovery device (2) can be reduced. It is possible to reduce the pressure quickly, and if there is an oil level rise that cannot be corrected by the bypass control by the bypass passage (50), the compressor (1) is stopped and the safety of the device can be achieved.

(Effect of the Invention) As described above, in the present invention, when the oil recovery device (2) is at a high level,
By controlling the return oil bypass by the bypass passage (5 or 50), the disturbance of the temperature distribution in the secondary equipment such as the evaporator can be almost eliminated, while avoiding the high level abnormality in the oil recovery device (2). can do.

Further, by providing the operation stopping means (9) and stopping the compressor (1) at the time of a high level abnormality that cannot be corrected by the bypass control, the safety of the device can be ensured.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing a first embodiment of a refrigerating apparatus according to the present invention, FIG. 2 is an electric circuit diagram of a control unit, FIG. 3 is a flow chart showing its operation, and FIG. 4 is a second embodiment. It is a piping system diagram showing. (1) ...... Compressor (2) ...... Oil collector (3) ...... Oil return path (4) ...... Oil cooler (5) ...... Bypass passage (6) ...... Opening and closing means (7) ...... High level detection means (8) …… Opening / closing control means (9) …… Operation stop means (50) …… Bypass passage

Claims (3)

[Claims] 1. An oil recovery device (2) is provided in a discharge path of a compressor (1).
A refrigerating apparatus having an oil cooler (4) in an oil return path (3) connecting the oil outlet of the oil collector (2) and the oil inlet of the compressor (1), The oil return path (3) is provided with a bypass passage (5) for bypassing a part of the oil passage in the oil cooler (4), and an opening / closing means (6) for opening and closing the bypass passage (5), The high level detection means (7) for detecting the high level limit value of the oil accumulated in the oil recovery device (2) and the opening / closing means (6) for a predetermined time when the high level is detected by the detection means (7) An opening / closing control means (8) for controlling the opening of the refrigerator is provided. 2. An oil recovery unit (2) is provided in the discharge path of the compressor (1).
A refrigerating apparatus having an oil cooler (4) in an oil return path (3) connecting the oil outlet of the oil collector (2) and the oil inlet of the compressor (1), The oil return path (3) is provided with a bypass passage (50) for bypassing the oil cooler (4), an opening / closing means (6) for opening and closing the bypass passage (50), and the oil recovery unit (2). ), A high level detecting means (7) for detecting a high level limit value of the oil accumulated in
A refrigeration system comprising: an opening / closing control means (8) for controlling the opening / closing means (6) to open for a predetermined time when a high level is detected by the detection means (7). 3. An operation stopping means (9) for stopping the compressor (1) when the high level is re-detected by the high level detecting means (7) after the opening / closing means (6) is controlled to open for a predetermined time. The refrigerating apparatus according to claim 1 or 2, further comprising: