JPS5848789A - Refrigerating device - Google Patents

Abstract

PURPOSE:To maintain the amount of lubricating oil in an operating compressor at proper amount by a method wherein the compressor, to be stopped upon number of operating sets controlling operation, and a suction pipe are connected through a solenoid valve, in the refrigerating device consisting of the compressors, provided in parallel and connected with each other by an oil equalizing pipe. CONSTITUTION:In a condition wherein the solenoid valve 11 is closed, a part of liquidous refrigerant medium discharged from the compressor main body 4a is mixed with and boiled in the lubricating oil in the compressor 1a, and vapor of the refrigerant medium, changed into buffles, is mixed with the lubricating oil, the most of it is flowed into the stopping compressor 1b through the oil equalizing pipe 5 and the lubricating oil stays in the stopping compressor 1b, therefore, the lubricating oil in the operating compressor 1a becomes insufficient. In this case, when the solenoid valve 11 is opened, the lubricating oil in the stopping compressor 1b is discharged into a suction pipe 8b due to a pressure difference, it is discharged into the operating compressor 1a through the suction pipe 8a together with the vapor of the refrigerant medium, the lubricating oil in the compressor 1a is increased, and whereby the insufficient lubrication or the trouble of seizure due to the incomplete lubrication may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system in which at least two compressors are connected in parallel and each compressor is controlled to save energy.

As shown in Fig. 1, in the conventional seed refrigeration system, the refrigerant discharged from two compressors 1a and 1b installed in parallel passes through discharge pipes 6i and 6b and piping 7 to a condenser (Fig. (not shown), is cooled by a cooling source and liquefied, is depressurized by a pressure reducing device (not shown), and is then introduced to an evaporator where it evaporates and exhibits its refrigerating ability.

The refrigerant vapor generated in the evaporator flows through the suction pipes Ba and Bb into the compressors 1a and 1b through the piping 9, and is compressed by the compressor bodies 4a and 4b.
The liquid flows through the machine 1b, and is further discharged through the pipe 7 through the discharge pipes 6m and 6b, respectively. The compressors 1m and 1b are connected to a pressure equalizing pipe 5 in order to keep the lubricating oil level at an appropriate level.

In the above-mentioned refrigeration system, when one compressor, for example, 1 m, is operated, most of the refrigerant vapor compressed by the compressor main body 4a is absorbed into the gap between the rotor 2a of the motor of the compressor 1a and the stator 3m. A part of the refrigerant vapor flows into the stop compressor 1b through the oil equalizing pipe 5, passes through the gap between the rotor 2b and the stator 3b of the motor, and is discharged from the discharge pipe 6b. .

During such single unit operation, during so-called wet compression in which liquid refrigerant is mixed in the refrigerant discharged from the compressor body 4m, a part of the liquid refrigerant discharged from the compressor body 4a is It flows into the lubricating oil and is heated by the lubricating oil, causing a phenomenon of boiling. This boiling foamy refrigerant vapor mixes with the lubricating oil, and this mixture increases in volume. A part of the mixture is discharged through the gap between the rotor 2a and stator 3a of the motor of the operating compressor 1m, but most of the remaining part is discharged into the stop compressor lb through the oil equalizing pipe 5 along with the flow of refrigerant vapor. and is separated into refrigerant vapor and lubricating oil. This separated refrigerant vapor is transferred to the rotor 2 of the motor.
The lubricating oil is discharged from the discharge pipe 6a through the gap between the lubricating oil b and the stator 3b, and the other lubricating oil remains in the compressor lb.

In such a state, the lubricating oil in the operating compressor la increases by an appropriate amount, and the oil level rises and becomes higher than the position of the oil equalizing pipe 5. There is a force that tries to return inside. However, the pressure inside the compressor is higher in the operating compressor 1a than in the stopped compressor 1b by an amount corresponding to the flow pressure loss of the refrigerant vapor, so the compression y
The function is to suppress the lubricating oil in Ib from returning to the compressor 1a. For this reason, there is a risk that the lubricating oil lid in the operating compressor la is insufficient, resulting in poor lubrication, and as a result, the operating compressor has the disadvantage of causing stiffness.

The present invention aims to eliminate the above-mentioned drawbacks and maintain an appropriate amount of lubricating oil in the operating compressor, so it is possible to
A refrigeration system in which Ia machines are connected to each other by an oil equalizing pipe is characterized in that the compressor, which is stopped during unit control operation, and the suction pipe are connected via a solenoid valve.

An embodiment of the present invention will be described below with reference to FIG. The same reference numerals as those shown in FIG. 1 indicate the same parts.

In Fig. 2, 1b is a compressor that is installed in parallel with compressor 1a and is stopped when one unit is in operation, 8M, 8b is a 1m compressor.
, 1b, respectively, and these two plate inlet pipes 8
The other ends of a and 8b are connected to each other. 10 is an oil return pipe connecting both plate inlet pipes 8a, 6b and the bottom of the compressor 1b;
11 is a solenoid valve provided in the oil return 1'' 110.
Since it is the same as the conventional example shown in the figure, the explanation will be omitted.

Next, the operation of this embodiment configured as described above will be explained.

When the solenoid valve 11 is in the closed state, as explained in the conventional example (Fig. 1), during wet compression when one unit is operated, a part of the liquid refrigerant discharged from the compressor main body 4a is absorbed into the lubricating oil in the compressor la. The lubricating oil heats it up and boils.

Therefore, the refrigerant vapor that has become foamy in the compressor la mixes with the lubricating oil in the compressor la to form a mixture. Most of this mixture flows into the stop compressor 1b through the oil equalizing pipe 5, and the lubricating oil remains in the stop pressure Jimmlb, so that the lubricating oil in the operating compressor la is insufficient.

When the solenoid valve 11 is opened in this state, the lubricating oil in the stop compressor lb is discharged into the inlet pipe 8b due to the pressure difference,
Suction pipe 8 with refrigerant vapor! After flowing into the compressor body 4a of the operating compressor 1a, it is discharged into the compressor la. For this reason, the lubricating oil in the compressor la, which has been in short supply until now, increases, so it is possible to prevent lubrication failure that often occurs due to lack of lubricating oil and the occurrence of steering accidents in the compressor la that occur due to this. Can be done.

If the opening time of the electromagnetic valve 11 is maintained longer than the time necessary for the amount of lubricating oil in the operating compressor la to become appropriate, the amount of lubricating oil flowing into the operating compressor 1m will exceed the appropriate amount. Since this excess oil amount is returned to the stop compressor 1b via the oil equalizing pipe 5, the lubricating oil in the operating compressor la is maintained at an appropriate amount. However, if the solenoid valve 11 is kept open for a long time,
Since high-pressure refrigerant vapor leaks to the low-pressure side and reduces the efficiency of the compressor, it is preferable to appropriately control the opening and closing of the solenoid valve 11.

As explained above, according to the present invention, when performing a number control operation, by always keeping the amount of lubricating oil in the operating compressor at an appropriate level, it is possible to prevent lubrication failure due to lack of lubricating oil and This makes it possible to prevent the occurrence of accidents involving the steering of the operating compressor.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional refrigeration system, and FIG. 2 is a sectional view of a main part of an embodiment of the refrigeration system of the present invention. 1a, 1b...Compressor, 5 river oil pipes, Bm, 6b...
・Suction pipe, lo...Oil return pipe, 11...Solenoid valve. Agent Patent attorney Toshiyuki Usuda 1 Inkomu ¥ 2 Diagram n

Claims (1)

[Claims] In a refrigeration system in which a refrigeration cycle is constituted by at least two compressors, an evaporator, a condenser, and a pressure reducing device installed in parallel, and the compressors are connected to each other by an oil equalizing pipe, the number of units is controlled. A refrigeration system characterized in that a compressor that is stopped at certain times and a suction pipe are connected via a solenoid valve.