JPH11337194A - Chiller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent refrigerating machine oil from being fed excessively from an oil tank to a compressor even if the difference between the inner pressure of the oil tank and the low pressure of refrigeration cycle increases. SOLUTION: The chiller has a refrigeration cycle comprising a condenser 8, a throttle 9, and an evaporator 10 coupled sequentially through piping and a plurality of compressors 12 having oil separators 3, 4 on the delivery side coupled in parallel through piping between the condenser 8 and the compressors 12. Oil level controllers 6, 7 of compressors 1, 2 fixed to the low pressure section thereof are coupled through piping with the oil separators 3, 4 and an oil tank 5 is coupled through piping with the low pressure side of refrigeration cycle via a check valve 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus used for a super showcase, a refrigerator, a thermostat, etc., and relates to a compressor using an HCFC-based or HFC-based refrigerant as a refrigerant.
The present invention relates to oil level control of a compressor of a refrigerator equipped with more than one unit.

[0002]

2. Description of the Related Art FIG. 8 shows a refrigerating apparatus equipped with, for example, two compressors. In the drawing, reference numeral 1 denotes a first low-pressure shell compressor, 2 denotes a second low-pressure shell compressor, and 3 denotes a first low-pressure shell compressor. 1 is an oil separator, 4 is a second oil separator, 5 is an oil tank, 6 is a first mechanical oil regulator, 7 is a second mechanical oil regulator, 8 is a condenser, 9 is a throttle device, Reference numeral 10 denotes an evaporator, 11 denotes a pressure control valve, and a condenser 8, a throttle device 9, and an evaporator 10 are connected in series with a pipe, and the condenser 8 and the evaporator 1 are connected.
A first low-pressure shell-type compressor 1 and a second low-pressure shell-type compressor 2 each having a first oil separator 3 and a second oil separator 4 on the discharge side during a period of 0 are connected in parallel by piping. Constructs a refrigeration cycle. The first oil separator and the second oil separator are connected to an oil tank 5, respectively, and the first mechanical oil regulator 6 and the second mechanical oil regulator 7 are each a first low pressure shell type. The compressor 1 and the second low-pressure shell type compressor 2 are connected to a low-pressure portion of the compressor 2 and are also connected to an oil tank 5. Further, the oil tank 5 is connected to the refrigeration cycle on a low pressure side via a pressure regulating valve 11.

The operation of this device is as follows. Refrigeration oil discharged together with refrigerant gas from the first low-pressure shell compressor 1 and the second low-pressure shell compressor 2 is supplied to a first oil separator 3 and a second oil separator. The refrigerant gas was separated from the refrigerant gas by the separator 4, and a low pressure and a constant differential pressure were obtained by the pressure regulating valve 11 installed in the pipe connecting the oil tank 5, which is a pressure relief circuit to the low pressure side, and the low pressure side of the refrigeration cycle. The oil is temporarily stored in the oil tank 5 maintained at the intermediate pressure. The first mechanical oil regulator 6 and the second mechanical oil regulator 7 attached to the first low-pressure shell compressor 1 and the second low-pressure shell compressor 2 respectively float the refrigerating machine oil. The oil level is detected by the compressor 1,
2 to keep the oil level constant. That is, the needle valve is opened by the lowering of the float following the lowering of the oil level to a predetermined height due to the decrease of the refrigerating machine oil, and the refrigerating machine oil is supplied from the oil tank 5 by the above-mentioned differential pressure. By the supply, the float rises to a predetermined height, the needle valve closes, the supply of the refrigerating machine oil is stopped, and the oil level of the compressors 1 and 2 is kept constant.

[0004]

However, the internal pressure of the oil tank 5 rises due to the high pressure rise due to the rise of the outside air temperature, and the relief amount of the pressure regulating valve 11 mounted on the pressure relief circuit from the oil tank 5 to the suction side. When the pressure difference between the internal pressure of the oil tank 5 and the low pressure of the refrigerating cycle increases, and the differential pressure exceeds the operating differential pressure of the mechanical oil regulators 6 and 7 attached to the compressors 1 and 2, the refrigerating machine oil Excessively flowed into the compressors 1 and 2 from the oil tank 5 in some cases. If excess oil is supplied to the compressor, the amount of oil lifted to the compression chambers of the compressors 1 and 2 increases, and the compressors 1 and 2 perform oil compression, thereby shortening the life.

[0005] In addition, when the refrigeration cycle is stopped due to the pump down, the low pressure is suddenly pulled in.
The pressure regulating valve 11 provided on the pressure relief circuit from the pressure to the suction side cannot follow up, and the differential pressure between the internal pressure of the oil tank 5 and the low pressure of the refrigeration cycle increases sharply, and the compressors 1, 2
, The refrigerating machine oil may excessively flow from the oil tank 5 into the compressors 1 and 2. Compressor 1, 2
When excessive oil is supplied to the compressor, the amount of lift of the oil of the compressors 1 and 2 to the compression chamber increases, and the compressors 1 and 2 perform oil compression, thereby shortening the service life.

Further, when a large amount of liquid refrigerant is started from a stagnation state on the low pressure side of the compressors 1 and 2 due to a long-term stoppage of the refrigeration cycle, a sudden low pressure change occurs and the oil tank 5 moves from the suction side to the suction side. The pressure regulating valve 11 installed on the pressure relief circuit cannot follow up, and the pressure difference between the internal pressure of the oil tank 5 and the low pressure of the refrigeration cycle rapidly increases, and the mechanical oil regulator 6 attached to the compressors 1 and 2 7, the refrigerating machine oil sometimes excessively flows from the oil tank 5 into the compressors 1 and 2. When excessive oil is supplied to the compressors 1 and 2, the amount of oil lifted into the compression chambers of the compressors 1 and 2 increases, and the compressors 1 and 2 perform oil compression and shorten the life. Become.

In the case where the refrigeration cycle is stopped for a long period of time as described above, the liquid refrigerant falls into the refrigerating machine oil of the compressors 1 and 2, and the refrigerant that has fallen at the start of the refrigeration cycle evaporates, which is called oil forming. A phenomenon occurs. At this time, the oil regulators 6 and 7 malfunction, and stable oil level control cannot be performed.

Further, the mechanical oil regulators 6 and 7 mounted on the compressors 1 and 2 have some leakage even within the range of the operating differential pressure, and the oil levels of the compressors 1 and 2 may become higher than necessary. .

[0009] The above-mentioned problem has been conventionally used.
The problem is not only HCFC-based refrigerants but also HFC-based refrigerants.
Also, due to its characteristics, the HFC-based refrigerant may generate sludge and clog the orifices of the oil regulators 6 and 7.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the differential pressure between the internal pressure of the oil tank and the low pressure of the refrigeration cycle is reduced by an increase in the internal pressure of the oil tank, a decrease in the pressure on the low pressure side of the refrigeration cycle, and the like. An object of the present invention is to prevent the refrigerating machine oil in the oil tank from being excessively supplied to the compressor even if it becomes larger, and to stably return the refrigerating machine oil from the oil tank to an appropriate amount. Even if the refrigerant cycle is stopped for a long period of time, the refrigerant oil in the oil tank is excessively supplied to the compressor even if the refrigerant suddenly evaporates at the time of start-up due to stagnation of the refrigerant into the refrigerant oil and oil forming occurs. It is an object of the present invention to prevent the refrigerating machine oil in the oil tank from being returned to the compressor in an appropriate amount stably. It is another object of the present invention to stably return a proper amount of refrigerating machine oil to a compressor even when a hydrofluorcarbon which easily generates sludge is used as a refrigerant.

[0011]

According to a first aspect of the present invention, a condenser, a throttle device, and an evaporator are sequentially connected to a pipe, and a plurality of oil separators are provided between the condenser and the evaporator on the discharge side. A refrigeration cycle in which the compressors are connected in parallel with pipes, an oil level controller of the compressor attached to the low-pressure section of the compressor, and an oil level controller of the oil separator and the compressor, respectively, and It has an oil tank connected to the low pressure side of the refrigeration cycle via a check valve.

Further, a second invention provides a condenser, a throttle device,
A refrigeration cycle in which a plurality of compressors each having an oil separator on the discharge side are connected in parallel between the condenser and the evaporator by connecting pipes to the evaporator in sequence, and compressors attached to low-pressure parts of the compressors, respectively. The oil tank connected to the oil level controller of the oil separator and the compressor, and the oil tank connected to the low pressure side of the refrigeration cycle via a pressure regulating valve. A first timer means for attaching an oil supply valve to the pipe between the oil level controllers, delaying the operation of the oil supply valve when the refrigeration apparatus starts, and opening the oil supply valve after a predetermined time has elapsed from the start of the refrigeration apparatus; Things.

Further, a third invention provides a condenser, a throttle device,
A refrigeration cycle in which a plurality of compressors each having an oil separator on the discharge side are connected in parallel between the condenser and the evaporator by connecting pipes to the evaporator in sequence, and compressors attached to low-pressure parts of the compressors, respectively. The oil tank connected to the oil level controller of the oil separator and the compressor, and the oil tank connected to the low pressure side of the refrigeration cycle via a pressure regulating valve. A refueling valve installed between the oil level controllers and a first for detecting the oil tank internal pressure
And a second pressure sensor that detects the low pressure side pressure of the refrigeration cycle, and receives the detection values of both pressure sensors, calculates the differential pressure, and closes the refueling valve when the differential pressure exceeds a predetermined value. A first refueling valve control device that opens the refueling valve when the differential pressure becomes equal to or less than a predetermined value.

A fourth invention provides a condenser, a throttle device,
A refrigeration cycle in which a plurality of compressors each having an oil separator on the discharge side are connected in parallel between the condenser and the evaporator by connecting pipes to the evaporator in sequence, and compressors attached to low-pressure parts of the compressors, respectively. The oil tank connected to the oil level controller of the oil separator and the compressor, and the oil tank connected to the low pressure side of the refrigeration cycle via a pressure regulating valve. A refueling valve mounted between the oil level controllers, a first temperature sensor for detecting the temperature of the refrigerant gas in the oil tank, and a temperature of the refrigerant gas inside the compressor or a temperature of the refrigerant gas sucked into the compressor. Second
The temperature sensor and both temperature sensors receive the detected values, convert them to pressure, calculate the differential pressure, close the refueling valve when the differential pressure exceeds a predetermined value, and close the refueling valve when the differential pressure falls below the predetermined value. And a second oil supply valve control device to be opened.

According to a fifth aspect of the present invention, in the second to fourth aspects, a second timer means for measuring an elapsed time since the refueling valve is closed is provided, and the measured value of the second timer means is a predetermined value. When the value is reached, the fuel supply valve is opened.

The sixth invention is the first to fifth inventions.
In the present invention, a hydrofluorocarbon is used as a refrigerant, and a sludge catching device is provided in a pipe between an oil tank and an oil level controller.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration diagram of a refrigeration apparatus according to Embodiment 1. FIG. 1 shows a refrigeration cycle equipped with two compressors as an example.
Is a first low-pressure shell compressor, 2 is a second low-pressure shell compressor, 3 is a first oil separator for the first low-pressure shell compressor 1, and 4 is a second low-pressure shell compressor The second oil separator for the compressor 2, 5 is an oil tank, 6 is for the first low-pressure shell-type compressor 1, a first mechanical oil regulator which is an oil level controller of the compressor, and 7 is a second oil separator. 2 is a second mechanical oil regulator for the low-pressure shell-type compressor 2 which is an oil level controller of the compressor, 8 is a condenser, 9 is a throttle device, 10 is an evaporator,
Reference numeral 12 denotes a check valve, which includes a condenser 8, a throttle device 9, and an evaporator 1.
0 are connected in series with a pipe, and a first low-pressure shell-type compressor 1 and a second low-pressure compressor each having a first oil separator 3 and a second oil separator 4 on the discharge side between the condenser 8 and the evaporator 10. The refrigeration cycle is configured by connecting low-pressure shell-type compressors 2 in parallel with piping. The first oil separator 3 and the second oil separator 4 are respectively connected to an oil tank 5, and the first mechanical oil regulator 6 and the second mechanical oil regulator 7 are respectively connected to a first low pressure While being connected to the low-pressure part of the shell-type compressor 1 and the second low-pressure shell-type compressor 2,
It is connected to the oil tank 5. Further, the oil tank 5 is connected to the refrigeration cycle on a low pressure side via a check valve 12.

The operation of this device is as follows. Refrigeration oil discharged together with the refrigerant gas from the first low-pressure shell compressor 1 and the second low-pressure shell compressor 2 is supplied to the first oil separator 3 and the second oil. The gas was separated from the refrigerant gas by the separator 4, and a low pressure and a constant differential pressure were obtained by a check valve 12 installed in a pipe connecting the oil tank 5 as a pressure relief circuit to the low pressure side and the refrigeration cycle low pressure side. The oil is temporarily stored in the oil tank 5 maintained at the intermediate pressure. The first mechanical oil regulator 6 and the second mechanical oil regulator 7 attached to the first low-pressure shell type compressor 1 and the second low-pressure shell type compressor 2 respectively use the float in the refrigerating machine oil. The oil level is detected and the compressors 1, 2
Is kept within a certain range. That is, as the oil level falls to a predetermined height due to the decrease of the refrigerating machine oil, the float lowers to a predetermined height, the needle valve opens, and the refrigerating machine oil is discharged from the oil tank 5 by the differential pressure. Supplied, the float rises to a predetermined height by the supply of the refrigerating machine oil, the needle valve closes, the supply of the refrigerating machine oil is stopped, and the oil level of the compressors 1 and 2 is kept within a certain range. Like that.

In the present embodiment, the oil tank 5 and the piping connection on the low pressure side of the refrigeration cycle are connected via a general pressure regulating valve 11 in the prior art, whereas in the present embodiment, the oil tank 5 side is connected. Check valve 12 communicating with lower pressure side
Connected through. The non-return valve 12 has better followability to pressure fluctuations than the general pressure regulating valve 11, prevents the differential pressure from rising due to sudden pressure fluctuations, and always operates within the operating differential pressure range of the mechanical oil regulators 6,7. By maintaining the differential pressure, stable oil level control can be performed.

Embodiment 2 FIG. 2 shows a configuration diagram of a refrigeration apparatus according to Embodiment 2. FIG. 2 shows 2 as an example.
1 shows a refrigeration cycle in which two compressors are mounted, and the components corresponding to those in FIG. 1 of the first embodiment are denoted by the same reference numerals and description thereof is omitted. In FIG. 2, 11 is a pressure regulating valve, 1
Reference numeral 7 denotes an oil supply valve 17 provided in a pipe between the oil tank 5 and mechanical oil regulators 6 and 7, which are oil level controllers of the compressor. Reference numeral 18 denotes an oil supply valve 17 when the refrigeration apparatus is started. This is a timer which is a first timer means for delaying the valve opening operation and opening the fuel supply valve 17 after a predetermined time has elapsed from the start of the refrigerating apparatus.

The operation of the refrigeration cycle and the mechanical oil regulators 6 and 7 in this embodiment is the same as that described in the first embodiment, except that an oil supply valve 17 and a timer 18 are installed, and At start-up, the elapsed time from start-up is measured by a timer -18, and after a predetermined time has elapsed from start-up, the refueling valve 17 is changed from closed to open. Even when the refrigerant is laid down in the compressor and vigorous forming occurs when the refrigerating apparatus is started, and the mechanical oil regulators 6 and 7 malfunction, a predetermined period of time during which the forming is reduced and the malfunction does not occur. Since the oil supply valve 17 is closed, unstable control of the oil level due to malfunction of the oil regulators 6 and 7 at the time of starting the refrigeration system can be prevented. Also, by using the check valve 12 as the pressure regulating valve 11 as in the first embodiment, a sudden pressure change exceeding the operating differential pressure range of the mechanical oil regulators 6 and 7 occurs even at the time other than the start. Even in the case where the pressure relief adjustment of the pressure adjustment valve 11 cannot keep up, it is possible to prevent excess refrigerating machine oil from flowing into the compressor, and to supply an appropriate amount of oil from the oil tank 5 to the compressor.

Embodiment 3 FIG. 3 and 4 show a third embodiment.
FIG. 1 is a diagram showing a configuration of a refrigeration apparatus according to the first embodiment. 3 and 4
Shows a refrigeration cycle equipped with two compressors as an example. Components corresponding to FIG. 1 of the first embodiment and FIG. 2 of the second embodiment are given the same reference numerals and description thereof is omitted.
3, reference numeral 13 denotes a first pressure sensor for measuring the internal pressure of the oil tank 5, and reference numerals 14 and 15 denote compressors 1 and 2, respectively.
The second pressure sensor, which is attached to the refrigeration cycle and measures the low pressure side pressure of the refrigeration cycle, receives the detection values of the respective pressure sensors, and receives the first pressure sensor 13, the second pressure sensors 14, 15, Is a first refueling valve control device that calculates the differential pressure of the fuel oil, closes the refueling valve 17 when the differential pressure exceeds a predetermined value, and opens the fueling valve 17 when the differential pressure becomes equal to or less than the predetermined value. . Then, a sudden pressure change occurs which exceeds the operating differential pressure range of the mechanical oil regulators 6 and 7 which are the oil level controllers of the compressor, and a pressure difference of the pressure regulating valve 11 that cannot keep up. Even if a state in which the pressure becomes large, by closing the oil supply valve 17, it is possible to prevent excess refrigerating machine oil from flowing into the compressor and to supply an appropriate amount of refrigerating machine oil. Stable oil level control is possible to keep the oil level within a certain range.

A modification of this embodiment will be described with reference to FIG. In FIG. 4, reference numeral 25 denotes a timer which is a second timer means for measuring an elapsed time after the refueling valve 17 is closed. First pressure sensor-13 and second pressure sensor-1
The difference between the detected pressures of the first and second oil supply valves 1 and 4
6. When the differential pressure exceeds a predetermined value, the fuel supply valve 17 is closed, and the elapsed time since the fuel supply valve is closed is counted by timer-2.
5, the refueling valve 17 is opened after a lapse of a predetermined time in which the differential pressure is expected to be equal to or less than a predetermined value. In the present modified example, the same effect can be obtained as compared with the case where the first refueling valve control device 16 opens and closes the refueling valve 17 by a differential pressure. Therefore, the first refueling valve control device 16
Can be simplified. Further, the check valve 1 is used as the pressure regulating valve 11.
By using 2, the reliability of oil level control of the compressor is further improved.

Embodiment 4 5 and 6 show a fourth embodiment.
FIG. 1 is a diagram showing a configuration of a refrigeration apparatus according to the first embodiment. 5 and 6
Shows a refrigeration cycle in which two compressors are mounted as an example. Components corresponding to the drawings in the first to third embodiments are given the same reference numerals, and description thereof is omitted. 5, reference numeral 19 denotes a first temperature sensor for detecting the temperature of the refrigerant gas in the oil tank 5, and reference numerals 20 and 21 denote compressors 1 and 2.
The second temperature sensors 22 attached to the compressors 1 and 2 for detecting the temperature of the internal low-pressure gas refrigerant or the temperature of the refrigerant gas sucked into the compressors 1 and 2 are the same as those of the respective temperature sensors. The detected value is input, converted into a pressure from an approximate expression of physical properties, and a differential pressure is calculated. When the differential pressure exceeds a predetermined value, the fuel supply valve 17 is closed. This is a second refueling valve control device that opens the valve 17. Then, a sudden pressure change occurs which exceeds the operating differential pressure range of the mechanical oil regulators 6 and 7 which are oil level controllers of the compressor, and the pressure relief of the pressure control valve check valve 11 catches up with the adjustment. Even if there is such a situation that the pressure difference becomes large, it is possible to prevent the excess refrigerating machine oil from flowing into the compressor by closing the refueling valve 17 and to supply an appropriate amount of the refrigerating machine oil. The point that the oil level can be stably controlled so as to keep the oil level in the compressor within a certain range is the same as that described in the third embodiment.

As shown in FIG. 6 as a modification of the present embodiment, the detection of the first temperature sensor 19 and the second temperature sensors 20 and 21 is the same as in the modification of the third embodiment. Based on the value, when the differential pressure calculated by the pressure conversion exceeds a predetermined value, the fuel supply valve 17 is closed, and the elapsed time since the fuel supply valve is closed is measured by the timer 25 as the second timer means. Alternatively, the refueling valve 17 may be opened after a lapse of a predetermined time in which the differential pressure is expected to be equal to or less than the predetermined value. In the present modified example, the same effect as opening and closing the oil supply valve 17 by the differential pressure in the first oil supply valve control device 16 is obtained.
Since the valve 7 is opened based on the time measured by the timer 25, the first refueling valve control device 16 can be simplified. Similarly, the reliability of the oil level control of the compressor is further improved by using the check valve 12 as the pressure regulating valve 11.

Embodiment 5 FIG. 7 shows a configuration diagram of a main part of a refrigeration apparatus according to Embodiment 5. In the figure,
Reference numerals 6 and 7 denote a first mechanical oil regulator and a second mechanical oil regulator which are oil level controllers of the compressors respectively corresponding to the two compressors. A sludge trapping device such as a strainer and a filter is provided in a pipe connecting the first mechanical oil regulator 6 and a pipe connecting the oil tank 5 and the second oil regulator 7. Other configurations are the same as those described in the first to fourth embodiments. According to the present embodiment, when the refrigerating machine oil is supplied from the oil tank 5 to each of the oil regulators 6 and 7, the mixed sludge is captured by the sludge capturing device 23 and the orifices of the oil regulators 6 and 7 are clogged. And the oil level of the compressor can be controlled stably. The present embodiment is effective for all refrigerants, but is particularly suitable for HFCs where sludge is easily generated.
System refrigerant (R404A, R407C, R410A, R50
7A). The installation position of the sludge catching device 23 is as shown in FIG. 7 by connecting pipes between the oil tank 5 and each of the oil regulators 6 and 7 and providing the sludge catching device 23 in a branch pipe of each oil regulator.
Can be prevented from becoming defective at the same time even if clogged with sludge. Also, even if the oil regulator 5 and the oil regulators 6 and 7 are provided in a common connecting pipe, the clogging of the orifices of the oil regulators 6 and 7 can be prevented, and stable oil level control of the compressor can be achieved. Of course, it is possible.

In each of the above-described embodiments, two compressors have been described. However, the number of compressors is not limited to two, and may be three or more, or one. Also, as a compressor,
Any type can be used as long as it is a low-pressure shell type. As the oil level controller, in addition to a mechanical oil regulator, a refrigerating machine oil based on a differential pressure based on a result of a liquid level detecting means and a liquid level detecting means of a compressor, such as a combination of a float switch and a solenoid valve. What is necessary is just to be provided with the supply and supply cutoff means. Further, in each of the above-described embodiments, an example is shown in which one oil supply valve 17 is installed in a common pipe portion on the oil tank 5 side of the pipe connecting the oil tank 5 and each of the oil level controllers 6 and 7. The oil supply valves 17 may be individually controlled for each compressor based on the pressure difference between the oil tank 5 and each compressor by installing the oil level controllers 6 and 7 in the branch pipes. By doing so, even if an abnormally high differential pressure is generated for each compressor, each compressor does not suffer from excessive refueling or insufficient refueling, and stable oil level control of a plurality of compressors becomes possible.

[0028]

As described above, the refrigerating apparatus according to the first aspect of the present invention has a condenser, a throttling device, and an evaporator connected in series to a pipe, and has an oil separator on the discharge side between the condenser and the evaporator. A refrigeration cycle in which a plurality of compressors are connected in parallel with pipes, a compressor oil level controller attached to each of the low-pressure sections of the compressor, and an oil separator and compressor oil level controllers. Since it has an oil tank connected to the low pressure side of the refrigeration cycle via a check valve and piping,
When the differential pressure rises due to sudden pressure fluctuations caused by a rise in the internal pressure of the oil tank due to a high pressure rise due to the rise of outside air, etc., the check valve has good followability to the pressure fluctuations. It can be within the operating differential pressure range of the controller, it is possible to prevent the refrigerating machine oil in the oil tank from being excessively supplied to the compressor, and it is possible to stably return the refrigerating machine oil from the oil tank to an appropriate amount, Stable oil level control can be performed.

The refrigeration apparatus according to the second invention comprises a plurality of compressors having a condenser, a throttle device, and an evaporator connected in series with a pipe, and having an oil separator on the discharge side between the condenser and the evaporator. A refrigeration cycle connected in parallel with a pipe, an oil level controller of the compressor attached to each of the low-pressure sections of the compressor, and an oil separator and an oil level controller of the compressor. An oil tank connected to the low-pressure side of the refrigeration cycle via a pipe, and a pipe between the oil tank and the oil level controller of the compressor. Since the first timer means for opening the refueling valve after a lapse of a predetermined time from the start of the refrigerating apparatus is provided, when the refrigerating apparatus is started for a long time after the refrigerating apparatus is stopped, a large amount of refrigerant is laid in the compressor, and Violently at startup Even if the oil level controller of the compressor malfunctions due to the occurrence of foaming, the oil supply valve is closed for a predetermined period of time so that the forming becomes small and the malfunction does not occur. It is possible to prevent unstable control of the oil level due to malfunction of the oil level controller of the machine.

The refrigeration apparatus according to the third aspect of the present invention comprises a plurality of compressors having a condenser, a throttle device, and an evaporator sequentially connected to a pipe and having an oil separator on the discharge side between the condenser and the evaporator. A refrigeration cycle connected in parallel with a pipe, an oil level controller of the compressor attached to each of the low-pressure sections of the compressor, and an oil separator and an oil level controller of the compressor. An oil tank connected to the low pressure side of the refrigeration cycle via a pipe, an oil supply valve mounted between the oil tank and an oil level controller of the compressor, a first pressure sensor for detecting an oil tank internal pressure, and a refrigeration cycle A second pressure sensor for detecting the low pressure side pressure and the detection values of the two pressure sensors, calculate the differential pressure, close the refueling valve when the differential pressure exceeds a predetermined value, the differential pressure is equal to or less than the predetermined value Open the refueling valve when Since the first refueling valve control device is provided, forming occurs when the refrigerating device is started, and the oil level may decrease within the time until the forming becomes small and the malfunction becomes small. Also, as soon as the differential pressure recovers to the predetermined value, the oil supply valve is opened, so that the refrigerating machine oil can be supplied to the compressor with good followability. In addition, even if the differential pressure rises and exceeds the operating differential pressure of the oil regulator, a signal to close the refueling valve is sent from the refueling control device and the refueling valve is closed, so that the refrigerating machine oil is supplied to the compressor. Excessive inflow can be prevented. Since the pressure is directly detected and controlled by the pressure sensor, the control method is simplified.

A refrigerating apparatus according to a fourth aspect of the present invention includes a plurality of compressors having a condenser, a throttle device, and an evaporator connected in series with a pipe, and having an oil separator on the discharge side between the condenser and the evaporator. A refrigeration cycle connected in parallel with a pipe, an oil level controller of the compressor attached to each of the low-pressure sections of the compressor, and an oil separator and an oil level controller of the compressor. Oil tank connected to the low pressure side of the refrigeration cycle via a pipe, an oil supply valve mounted between the oil tank and an oil level controller of the compressor, and a first temperature sensor for detecting a refrigerant gas temperature in the oil tank And a second temperature sensor for detecting the temperature of the refrigerant gas inside the compressor or the temperature of the refrigerant gas sucked into the compressor, receiving the detection values of both temperature sensors, converting the pressure into pressure, calculating the differential pressure, and calculating the differential pressure. Refuel when the specified value is exceeded Was closed, because the pressure difference has a second oil supply valve controller to open the refueling valve When equal to or less than a predetermined value, follower at startup of the refrigeration apparatus - is timing occurs, follower -
Even if the oil level drops within the time until the ming becomes smaller and the malfunction becomes smaller, the oil supply valve is opened as soon as the differential pressure recovers to the predetermined value. Can be supplied. In addition, even if the differential pressure rises and exceeds the operating differential pressure of the oil regulator, a signal to close the refueling valve is sent from the refueling control device and the refueling valve is closed, so that the refrigerating machine oil is supplied to the compressor. Excessive inflow can be prevented. Since an inexpensive temperature sensor can be used, the cost can be reduced.

Further, the refrigeration apparatus according to the fifth aspect of the present invention is the refrigeration apparatus according to the second to fourth aspects, further comprising a second timer means for measuring an elapsed time since the fuel supply valve was closed. When the measured value reaches a predetermined value, the refueling valve is opened, so that control for closing the refueling valve and then opening the refueling valve becomes easy.

A refrigeration apparatus according to a sixth aspect of the present invention is the refrigeration apparatus according to the first to fifth aspects, wherein a hydrofluorocarbon is used as a refrigerant and a sludge trapping device is provided in a pipe between an oil tank and an oil level controller. Therefore, even if an HFC-based refrigerant that easily generates sludge is used, sludge clogging of the oil level controller of the compressor can be prevented, and stable oil level control of the compressor can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a refrigeration apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a configuration diagram of a refrigeration apparatus according to Embodiment 3 of the present invention.

FIG. 4 is a configuration diagram of a modification of the refrigeration apparatus according to Embodiment 3 of the present invention.

FIG. 5 is a configuration diagram of a refrigeration apparatus according to Embodiment 4 of the present invention.

FIG. 6 is a configuration diagram of a modification of the refrigeration apparatus according to Embodiment 4 of the present invention.

FIG. 7 is a main part configuration diagram of a refrigeration apparatus according to Embodiment 5 of the present invention.

FIG. 8 is a configuration diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

1,2 compressor, 3,4 oil separator, 5 oil tank, 6,7 oil level controller, 8 condenser, 9 throttle device,
DESCRIPTION OF SYMBOLS 10 Evaporator, 11 Pressure control valve, 12 Check valve, 13
First pressure sensor, 14, 15 Second pressure sensor, 16 First refueling valve control device, 17 Refueling valve, 18
First timer means, 19 first temperature sensor, 2
0, 21 second temperature sensor, 22 second refueling valve control device, 23 sludge trapping device, 25 second timer means.

Claims (6)

[Claims] 1. A refrigeration cycle in which a condenser, a throttle device, and an evaporator are sequentially connected to a pipe, and a plurality of compressors each having an oil separator on a discharge side are connected in parallel between the condenser and the evaporator. And an oil level controller of the compressor attached to the low pressure section of the compressor, and a pipe connection to the oil separator and the oil level controller of the compressor, respectively, and the refrigeration through a check valve. A refrigeration system including a low-pressure side of the cycle and an oil tank connected to a pipe. 2. A refrigeration cycle in which a condenser, a throttle device, and an evaporator are sequentially connected to a pipe, and a plurality of compressors each having an oil separator on a discharge side are connected in parallel between the condenser and the evaporator. Connecting the oil level controller of the compressor mounted on the low-pressure section of the compressor, the oil separator and the oil level controller of the compressor, and connecting the oil level controller of the compressor to the refrigeration cycle via a pressure regulating valve. An oil tank connected to the low-pressure side of the oil tank, and an oil supply valve is attached to a pipe between the oil tank and the oil level controller of the compressor, delaying the operation of the oil supply valve when the refrigeration apparatus is started, A refrigeration apparatus comprising: first timer means for opening the fuel supply valve after a predetermined time has elapsed from the start. 3. A refrigeration cycle in which a condenser, a throttle device, and an evaporator are sequentially connected to a pipe, and a plurality of compressors each having an oil separator on a discharge side are connected in parallel between the condenser and the evaporator. Connecting the oil level controller of the compressor mounted on the low-pressure section of the compressor, the oil separator and the oil level controller of the compressor, and connecting the oil level controller of the compressor to the refrigeration cycle via a pressure regulating valve. An oil tank connected to the low pressure side of the compressor, an oil supply valve mounted between the oil tank and an oil level controller of the compressor, a first pressure sensor for detecting the oil tank internal pressure, and a refrigeration cycle. A second pressure sensor for detecting the low pressure side pressure, and the detection values of the two pressure sensors are received, the differential pressure is calculated, and when the differential pressure exceeds a predetermined value, the refueling valve is closed, and the differential pressure is reduced. It has fallen below the specified value A first refueling valve control device for opening the refueling valve. 4. A refrigeration cycle in which a condenser, a throttle device, and an evaporator are sequentially connected to a pipe, and a plurality of compressors each having an oil separator on a discharge side are connected in parallel between the condenser and the evaporator. Connecting the oil level controller of the compressor mounted on the low-pressure section of the compressor, the oil separator and the oil level controller of the compressor, and connecting the oil level controller of the compressor to the refrigeration cycle via a pressure regulating valve. An oil tank connected to the low pressure side of the oil tank, an oil supply valve mounted between the oil tank and an oil level controller of the compressor, and a first temperature sensor for detecting a refrigerant gas temperature in the oil tank. A second temperature sensor that detects a refrigerant gas temperature inside the compressor or a refrigerant gas temperature sucked into the compressor, receives detection values of the two temperature sensors, converts the pressure into pressure, calculates a differential pressure, Prescribed differential pressure When the value exceeds, close the refueling valve,
A refueling valve control device for opening the refueling valve when the differential pressure becomes equal to or less than a predetermined value. 5. A fuel supply system comprising: a second timer for measuring an elapsed time since the fueling valve is closed; and when the measured value of the second timer reaches a predetermined value, the fueling valve is opened. The refrigeration apparatus according to claim 3 or 4, wherein: 6. The refrigerating apparatus according to claim 1, wherein a hydrofluorocarbon is used as a refrigerant, and a sludge catching device is provided in a pipe between the oil tank and the oil level controller. .