JPH10220885A - Refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of a plate type cooler by the pressure fluctuation of lubricating oil, in a refrigerating machine, cooled by a method wherein refrigerant, discharged out of a compressor, is circulated in the sequence of a condenser, an expansion valve and an evaporator while a part of liquid refrigerant, extracted out of the condenser, is circulated into the evaporator through a plate type oil cooler and lubricating oil, lubricating the required lubricating places of a compressor, is cooled through heat exchange between the refrigerant in the plate type cooler. SOLUTION: The pressure fluctuation of lubricating oil near a plate type oil cooler 17 is detected by a pressure sensor 20 and when the detected pressure has exceeded a preset pressure, a controller 21 outputs to a solenoid opening and closing valve 22 to open the same. According to this operation, the pressure of pressurized gas, such as N2 or the like which is filled into an accumulator 26 from a gas vessel 23 through a valve 24, is impressed on the lubricating oil near the plate type coil cooler 17 to restrain the pressure fluctuation of the lubricating oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigerator such as a centrifugal refrigerator.

[0002]

2. Description of the Related Art A system diagram of a conventional centrifugal chiller is shown in FIG. During operation of the turbo refrigerator, the gas refrigerant discharged from the turbo compressor 8 is condensed and liquefied in the condenser 10 and is expanded.
It is adiabatically expanded by being squeezed by 11, vaporized and vaporized by the evaporator 12, again enters the turbo refrigerator 8, is sucked into the impeller 14 via the suction valve 15, and is compressed again.

[0003] The impeller 14 is driven by a motor 13 via a shaft 19, which is supported by a bearing 9.

A part of the liquid refrigerant condensed and liquefied in the condenser 10 is supplied to a valve.
The oil enters the plate-type oil cooler 17 through the coolant passage 17.
b flows into the evaporator 12, where it merges with the liquid refrigerant coming through the expansion valve 11 and evaporates.

On the other hand, the lubricating oil in the oil tank 1 is
, And enters the oil cooler 17 and is cooled by exchanging heat with the liquid refrigerant in the course of flowing through the oil flow path 17a. Next, the lubricating oil enters the turbo compressor 8 and after lubricating the bearing 9 and other necessary lubricating points, is discharged from the drain discharge port 18 and returns to the oil tank 1. Reference numeral 2 denotes an oil level gauge attached to the oil tank 1.

[0006]

In the above-mentioned conventional turbo chiller, since the lubricating oil comes into contact with the gas refrigerant in the atmosphere in the process of flowing through the turbo compressor 8, a large amount of the refrigerant dissolves in the lubricating oil. . When the lubricating oil is cooled by exchanging heat with the refrigerant in the oil cooler 17, the refrigerant dissolved in the lubricating oil flash-evaporates, so that a steep oil pressure fluctuation (150 to 20
(0HZ, amplitude 50K), and this pressure fluctuation is repeatedly applied to the partition wall that separates the refrigerant flow path 17b and the oil flow path 17a of the oil cooler 17, so that the partition wall may be broken by high cycle fatigue. Was.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and the gist of the present invention is that a refrigerant discharged from a compressor is supplied to a condenser, an expansion valve and an evaporator. In this order, a part of the liquid refrigerant extracted from the condenser circulates through the plate type oil cooler to the evaporator, and the lubricating oil for lubricating the required lubrication points of the compressor is the plate type oil. In a refrigerator cooled by exchanging heat with a refrigerant in a cooler, pressure fluctuation of lubricating oil near the plate-type oil cooler is detected, and when this exceeds a preset value, the gas pressure is increased. A refrigerator is characterized in that it is applied to lubricating oil near a plate-type oil cooler to suppress its pressure fluctuation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIG. In the vicinity of the oil cooler 17, there is provided a strain gauge type high-speed response type pressure sensor 20 for detecting the pressure of the lubricating oil flowing into the oil cooler 17, and the detected pressure of the pressure sensor 20 is controlled by the controller 21.
Is input to When the detected pressure exceeds the preset pressure, the controller 21 outputs the detected pressure to the electromagnetic on-off valve 22 to open it.

Then, a pressurized gas composed of N ₂ gas or the like previously filled in the accumulator 25 from the cylinder 23 via the valve 24 flows into the oil cooler 17 through the gas pipe 26 and the electromagnetic switching valve 22. Applied to the oil, this steep pressure fluctuation of the lubricating oil is suppressed. Other configurations and operations are the same as those of the conventional one shown in FIG. 2, and corresponding members are denoted by the same reference numerals and description thereof is omitted.

It is also possible to detect the pressure of the lubricating oil flowing out of the oil cooler 17 in the vicinity thereof and apply a pressurized gas to the lubricating oil. The present invention is not limited to the centrifugal chiller, and is of course applicable to all types of chillers having a plate-type oil cooler.

[0011]

According to the present invention, the pressure fluctuation of the lubricating oil near the plate type oil cooler is detected, and when the pressure fluctuation exceeds a preset pressure, the gas pressure is changed to the lubricating amount near the plate type oil cooler. Since the applied pressure is applied to the oil to suppress its pressure fluctuation, it is possible to prevent the partition wall of the plate type oil cooler from being broken by the fluctuation of the pressure of the lubricating oil.

Accordingly, it is possible to prevent the refrigerator from becoming inoperable due to a decrease in oil pressure or a decrease in oil amount due to the lubricating oil flowing into the refrigerant system in the oil cooler.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional turbo refrigerator.

[Explanation of symbols]

 8 Compressor 9 Bearing 13 Motor 14 Impeller 15 Intake valve 19 Shaft 18 Drain outlet 10 Condenser 11 Expansion valve 12 Evaporator 17 Oil cooler 17a Oil flow path 17b Refrigerant flow path 20 Pressure sensor 21 Controller 23 Gas cylinder 24 Valve 25 Accumulator 26 Gas pipe 22 Solenoid on-off valve 1 Oil tank 3 Oil pump

Claims (1)

[Claims] 1. A refrigerant discharged from a compressor circulates through a condenser, an expansion valve and an evaporator in this order, and a part of the liquid refrigerant extracted from the condenser passes through a plate type oil cooler to the evaporator. In the refrigerator, the lubricating oil circulating to the required lubricating points of the compressor is cooled by exchanging heat with the refrigerant in the plate-type oil cooler. A refrigerator that detects pressure fluctuations and applies a gas pressure to lubricating oil near the plate-type oil cooler when the pressure fluctuations exceed a preset value to suppress the pressure fluctuations.