JPH05164416A - Refrigerator - Google Patents

Abstract

PURPOSE:To provide a refrigerator that is environmentally preferable because the coolant in the coolant circuit is not discharged when the condenser is replaced or separated by providing a valve in the piping between the condenser and liquid receiver and a check valve in the piping that applies the pressure on high pressure side to an oil return pipe and capacity control valve. CONSTITUTION:The piping between a condenser 5 and liquid receiver 6 is provided with a valve 61, and an oil return pipe 10 is provided with a check valve 32 and, at the same time, the piping for applying the pressure on the high pressure side to a capacity control valve 33 is provided with a check valve 45. With this constitution, when the condenser 5 is replaced or separated, at first the service valves 54, 55 on the discharge sides of compressors 2,3 are closed, and the valve 61 between the condenser 5 and liquid receiver 6 is closed. With these closing actions only the channels on the suction side and discharge side of the condenser 5 can be shut off from the coolant circuit. The coolant that is discharged to the outside when the condenser 5 is replaced or separated is, therefore, a small amount of the coolant that is left in the piping on the suction side of the condenser 5 and in an oil separator 4 and in the condenser 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device for cooling a refrigerating / refrigerating showcase, a prefabricated refrigerator or the like used in a convenience store, a supermarket or the like.

[0002]

2. Description of the Related Art Heretofore, this type of refrigerating apparatus has been used in the actual construction of Sho 56
As described in JP-A-8876, etc., a plurality of compressors, oil separators, condensers, liquid receivers, pressure reducing devices, and evaporators are connected by piping, and separated by the oil separators. The oil is returned to each compressor by an oil return pipe. Further, this type of refrigerating device is usually charged with a refrigerant on site because it is usually installed outdoors.

[0003]

However, when the condenser is replaced or separated after installation, most of the refrigerant in the refrigerant circuit is discharged and the refrigerant is wasted, which is environmentally preferable. Absent. In addition, in this type of refrigeration system, a compressor may be provided with a discharge gas bypass type capacity control mechanism. In this case, not only the gas release but also the capacity control valve due to back pressure change after replacement of the condenser. However, there is a problem that the refrigeration system becomes unstable.

The present invention has been made in view of the above point, and even when the condenser is replaced or separated after the refrigerating apparatus is installed, the refrigerant in the refrigerant circuit is not discharged and the refrigerating apparatus is environmentally preferable. The purpose is to provide.

[0005]

According to the present invention, a plurality of compressors, oil separators, condensers, liquid receivers, pressure reducing devices, and evaporators are connected by pipes, and separated by the oil separators. The returned oil is returned to each compressor by an oil return pipe, and a discharge gas bypass type capacity control valve is provided in the compressor, and a high pressure side pressure and a low pressure side pressure are selectively applied to the back pressure of this capacity control valve. In order to control the capacity, an opening / closing valve is provided in the pipe between the condenser and the liquid receiver, a check valve is provided in the oil return pipe, and a high pressure side pressure is applied to the capacity control valve. A check valve is provided in the pipe.

[0006]

According to the refrigerating apparatus of the present invention, when the condenser is replaced or separated, first, the service valve on the discharge side of each compressor is closed, and the condenser between the condenser and the liquid receiver is closed. By simply closing the on-off valve, the suction side and discharge side paths of the condenser can be cut off from the refrigerant circuit,
The refrigerant discharged to the outside of the circuit during replacement and separation of the condenser is only a small amount of the refrigerant remaining in the suction side piping of the condenser, in the oil separator and in the condenser. It is possible to provide an environment-friendly refrigeration system that can prevent its release into the atmosphere and does not adversely affect the destruction of the ozone layer.

Since the oil return pipe is provided with a check valve, the pressure in the oil return pipe does not drop when the condenser is replaced, and the reverse flow of oil due to a malfunction can be prevented.

Further, since the check valve is also provided in the pipe for applying the high pressure side pressure to the capacity control valve, the back pressure of the capacity control valve changes when the condenser is replaced, and the capacity control valve malfunctions. The stable capacity control of the refrigeration system can be continuously performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 is a refrigerating apparatus. This device includes a 7-hp fully enclosed scroll compressor 2 and a 5-hp fully enclosed scroll compressor 3, an oil separator 4, a condenser 5, a liquid receiver 6, and expansion valves 7a and 7b. , Evaporators 8a, 8b,
The accumulators 9a and 9b are connected by piping. An on-off valve 61 for separating the condenser 5 is connected to a pipe between the condenser 5 and the liquid receiver 6.

Reference numeral 10 is an oil return pipe connecting the oil separator 4 and the compressors 2 and 3, and the oil return pipe is branched from the middle and is connected to the compressors 2 and 3 by branch pipes 10a, 10
b. 11 and 12 are solenoid valves attached to the respective branch pipes 10a and 10b, and 11a and 12a are the respective branch pipes 10a and 10a.
Capillary tube attached to 10b, 13, 1
Reference numeral 4 is an oil level adjuster attached to each of the compressors 2 and 3.
Reference numeral 32 is a check valve provided in the oil return pipe 10.

Since the oil level adjusters 13 and 14 have the same structure, the structure will be described by taking the oil level adjuster 13 as an example. The container body 15 is formed by drawing a copper pipe and has an opening 16 in the upper portion. An insertion tube 17 made of a copper tube which is inserted from the opening 16 of the container body and fixed in the container body, and the lower end of which is closed by drawing, and stoppers 18 and 19 which are fixed to the upper and lower positions of the insertion tube. A float 20 vertically movably inserted into the insertion tube 17 between the stoppers 18 and 19, and a magnet 28 built in the float.
A substrate 22 having a reed switch 21 inserted into the insertion tube 17, and the insertion tube 17 led out from the substrate 22.
The epoxy resin material 25 for sealing the lead wire 24 drawn out from the upper end opening 23 of the inside of the collar 29 fixed to the upper portion of the insertion tube 17, and one end brazed to the upper side surface of the container body 15 and the other end. Is composed of a pressure equalizing pipe 26 connected to the lower upper side of the compressor 2, and an oil equalizing pipe 27 having one end brazed to the lower side surface of the container body 15 and the other end connected to the lower lower side of the compressor 2. ing.

The oil level adjusters 13 and 14 are electrically connected to a control device 31 via a lead wire 24, and the control device 31 operates on the basis of signals from the oil level adjusters. It controls the opening / closing operation of the valves 11 and 12.

In the oil level controller 13, the reed switch 21 is excited when the amount of oil in the container 15 is proper, that is, when the oil level is between points A and B in FIG. No signal is output because the contact is opened. Next, when there is a large amount of oil in the container 15, that is, when there is a large amount of oil in the compressor 2 (when the oil level reaches point A), the float 20 rises and the reed switch 21
Is no longer excited and an OFF signal is generated, so that an OFF signal is output from the control device 31 to the solenoid valve 11, and the solenoid valve 11 is closed. Therefore, the oil is not supplied from the oil separator 4 to the compressor 2, and the oil level in the compressor 2 is maintained at an appropriate level. When the oil in the container 15 is low, that is, when the oil in the compressor 2 is low (when the oil level is below the point B), the float 20
Is lowered, the reed switch 21 is not excited, an ON signal is generated, the ON signal is output from the control device 31 to the solenoid valve 11, and the solenoid valve 11 is opened. Therefore, oil is supplied from the oil separator 4 to the compressor 3 via the oil return pipe 10 and the branch pipe 10a. This oil supply is stopped when the oil level in the container 15 rises and reaches a level slightly exceeding point B. That is, since the reed switch 21 has hysteresis, the reed switch 21 is excited by the magnet 28 around the point B, and the OFF signal is output due to the opening of the contact due to this excitation. Is stopped by closing.

The same oil level control is performed on the oil level adjuster 14.

Reference numeral 33 is a capacity control valve built in the compressor 3, and this capacity control valve 33 bypasses some of the gas compressed in the high pressure chamber 34 to the intermediate pressure chamber 35.
7, a pressure introducing pipe 39 for applying a back pressure into the valve chamber 38, a high pressure introducing pipe 41 connecting the pressure introducing pipe 39 and the high pressure side pipe 40, the pressure introducing pipe 39 and the low pressure side pipe 42.
And a low-pressure pressure introducing pipe 43 that connects
A solenoid valve 44 and a check valve 45 are connected to the high pressure introduction pipe 41, and a solenoid valve 46 is connected to the low pressure introduction pipe 43. When the capacity of the refrigerating apparatus 1 is controlled, the capacity control valve 33 is opened by opening the electromagnetic valve 46 and closing the electromagnetic valve 44 to apply back pressure on the low pressure side, and the discharge gas of the compressor 3 is discharged. Bypass a part of the device to control the capacity of the device. When the capacity control is not performed, the electromagnetic valve 44 is opened, the electromagnetic valve 46 is closed, and the back pressure on the high pressure side is applied to close the valve, and the compressor 3 is operated at the normal capacity.

Reference numeral 47 is a refrigerant injection pipe for injecting a part of the liquid refrigerant discharged from the liquid receiver 6 into each of the compressors 2 and 3 to cool the compressor. The refrigerant injection pipe is branched from the middle to branch pipes 47a reaching the compressors 2 and 3,
47b and each branch pipe has a solenoid valve 48, 49.
And the control valves 50 and 51 are connected. In the refrigerant injection circuit, the solenoid valves 48 and 49 are opened at the same time when the refrigeration system 1 is operated, and the branch pipes 47a and 4 are opened.
The liquid refrigerant flowing through 7b is throttled by the control valves 50 and 51 to be in a gas-liquid mixed state and supplied to the compressors 2 and 3. Here, the control valves 50 and 51 are controlled by the temperature sensitive tubes 52 and 53 provided in the discharge pipes 54 of the compressors 2 and 3 depending on the discharge gas temperature so as to obtain a predetermined degree of superheat with respect to the condensation pressure. The opening is adjusted linearly.

54 and 55 are discharge side service valves provided at the discharge ports of the compressors 2 and 3, 56 and 57 are suction side service valves, 58 and 59 are strainers, and 60 is a liquid pipe service valve.

In the refrigerating apparatus 1 constructed as described above, since the opening / closing valve 61 is provided in the pipe between the condenser 5 and the liquid receiver 6, when the condenser 5 is replaced or separated, First, the discharge side service valves 54, 55 of the compressors 2, 3
The suction side and discharge side paths of the condenser 5 can be cut off from the refrigerant circuit only by performing the work of closing the on-off valve 61 and closing the on-off valve 61, and discharged to the outside of the circuit when the condenser 5 is replaced or separated. Since only a small amount of refrigerant remains in the suction side pipe 40 of the condenser 5, in the oil separator 4 and in the condenser 5, many refrigerants in the circuit are released to the atmosphere. It is possible to provide the refrigerating apparatus 1 that can be prevented and does not adversely affect the destruction of the ozone layer and is environmentally preferable.

Further, since the oil return pipe 10 is provided with the check valve 32, the pressure in the oil return pipe 10 does not drop when the condenser 5 is replaced, and the oil reverse flow due to the malfunction occurs. Can be prevented.

Further, since the check valve 45 is also provided in the high pressure introducing pipe 41 for applying the high pressure side pressure to the capacity control valve 33, the back pressure of the capacity control valve 33 changes when the condenser 5 is replaced. The capacity control valve 33 is prevented from malfunctioning, and stable capacity control of the refrigeration system 1 can be continuously performed.

[0022]

As described above, according to the present invention, when exchanging or separating the condensers, first, the service valve on the discharge side of each compressor is closed so that the space between the condenser and the receiver is reduced. It is possible to cut off the suction side and discharge side paths of the condenser from the refrigerant circuit simply by closing the opening / closing valve of the condenser, and the refrigerant discharged to the outside of the condenser circuit when the condenser is replaced or separated is Since only a small amount of refrigerant remains in the suction side pipe, in the oil separator, and in the condenser, it is possible to prevent a large amount of refrigerant in the circuit from being released into the atmosphere, and to destroy the ozone layer. It is possible to provide an environment-friendly refrigeration system that does not adversely affect.

Further, since the oil return pipe is provided with the check valve, the pressure in the oil return pipe does not drop when the condenser is replaced, and the reverse flow of oil due to a malfunction can be prevented.

Further, since the check valve is also provided in the pipe for applying the high pressure side pressure to the capacity control valve, the back pressure of the capacity control valve changes when the condenser is replaced, and the capacity control valve malfunctions. The stable capacity control of the refrigeration system can be continuously performed.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing a refrigerant circuit diagram of a refrigeration apparatus of the present invention.

FIG. 2 is a vertical sectional view of an oil level adjuster.

FIG. 3 is a sectional view showing a main part of an oil level adjuster.

[Explanation of symbols]

 2,3 Compressor 10 Oil return pipe 11,12 Solenoid valve 13,14 Oil level controller 32 Check valve 33 Capacity control valve 41 High pressure introduction pipe 44,46 Solenoid valve 45 Check valve 61 Open / close valve

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshio Ida 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A plurality of compressors, an oil separator, a condenser, a liquid receiver, a decompression device, and an evaporator are connected by piping, and the oil separated by the oil separator is connected by an oil return pipe. In addition to returning to the compressor, a discharge gas bypass type capacity control valve is provided in the compressor, and capacity control is performed by selectively applying high pressure side pressure and low pressure side pressure to the back pressure of this capacity control valve. An on-off valve is provided in the pipe between the condenser and the liquid receiver,
A refrigeration system comprising a check valve provided in the oil return pipe and a check valve provided in a pipe for applying a high pressure side pressure to the capacity control valve.