JPS6152906B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a centrifugal refrigerator, particularly to a lubrication system.

FIG. 1 shows the refrigerant gas and lubricating oil system of a conventionally known centrifugal refrigerator.

In the figure, 1 is a centrifugal compressor (hereinafter referred to as a compressor), 2 is a speed increaser for the compressor 1, 3 is a motor, 4 is an oil sump chamber, 5 is a motor room, and 6 is a motor chamber 5 and an oil sump. A seal that partitions the chamber 4, 7 a seal that partitions the oil reservoir chamber 4 and compressed refrigerant gas, 8 a condenser, 9 an expansion valve, 10 an evaporator, 11 an oil tank, 12 an oil pump, 13 an oil supply pipe, 1
4 is an oil return pipe from the oil reservoir chamber 4 to the oil tank 11, 15 is a pressure equalizing pipe between the oil tank 11 and the compressor suction side, and 16 is an expansion valve for cooling the motor.

Next, the refrigerant gas system and oil system will be explained. The refrigerant gas vaporized in the evaporator 10 is compressed in the compressor 1, liquefied in the condenser 8, depressurized in the expansion valve 9, and enters the evaporator 10 again to form a refrigeration cycle.
A portion of the refrigerant liquid condensed in the condenser 8 passes through a motor cooling expansion valve 16 and is used to cool the motor. The lubricating oil is passed through the oil supply pipe 13 by the oil pump 12 to lubricate lubricated parts such as the compressor bearing (not shown) and the speed increaser 2, and then is sent to the oil reservoir chamber 4 through the accumulated oil return pipe 14. Return to oil tank 11.

The oil tank 11 is connected to the compressor 1 by a pressure equalizing pipe 15.
Since the pressure is equalized with the suction side of the lubricating oil, the pressure is kept low during operation, making it easy to return oil from the oil reservoir chamber 4 to the oil tank 11, and minimizing the mixing of refrigerant gas into the lubricating oil.

(Note: The higher the pressure, the greater the mixing rate of refrigerant gas into lubricating oil.) Conventional refrigerant gas and lubricating oil systems are configured as described above, so the internal pressure of the oil tank is equal to the start-up of the compressor. At the same time, it decreases rapidly. As a result, the refrigerant gas mixed in the lubricating oil in the oil tank rapidly foams (so-called forming), reducing the volumetric efficiency of the oil pump and making it impossible to secure the necessary amount of oil supply, causing the refrigerator to malfunction. This caused problems with driving.

This idea was made to eliminate the drawbacks of the conventional ones as mentioned above, and in order to prevent the internal pressure of the oil tank from dropping suddenly, a part of the high pressure gas on the discharge side of the compressor flows into the oil reservoir chamber. This provides a centrifugal refrigeration system that can maintain stable refueling.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 2, reference numeral 17 denotes pressure regulating means consisting of a capillary tube provided in the middle of a pipe that communicates the discharge side of the compressor 1 with the oil reservoir chamber 4. Note that the other symbols are the same as those in FIG. 1, and therefore their explanation will be omitted.

By appropriately selecting the inner diameter and length of the capillary tube which is the pressure adjusting means 17, the oil reservoir chamber 4,
By maintaining the oil return pipe 14 and the oil tank 11 at appropriate pressures, forming can be suppressed and troubles such as poor oil supply when starting up the refrigerator can be prevented.

Instead of the capillary tube, a pressure regulating device such as an orifice or a pressure regulating valve may be used as the pressure regulating means.

In addition, as shown in Fig. 3, a flow path opening/closing means 18 such as a stop valve or an automatic valve is provided either before or after pressure regulating equipment such as a capillary tube, and the oil sump chamber is opened only for the necessary time when starting the refrigerator. It is also possible to allow refrigerant gas to flow in. Furthermore, the present invention can be similarly applied to a system in which an oil tank and an oil reservoir are integrated.

As described above, according to this invention, since a part of the high-pressure refrigerant gas is excessively introduced into the oil reservoir chamber, the degree of forming during startup can be suppressed to a small level. Therefore, there is an effect of preventing troubles in the lubrication system.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of refrigerant gas and lubricating oil in a conventional centrifugal refrigeration system, Fig. 2 is a system diagram of refrigerant gas and lubricating oil in a centrifugal refrigeration system according to an embodiment of this invention, and Fig. 3 is a system diagram of refrigerant gas and lubricating oil in a conventional centrifugal refrigeration system. FIG. 3 is a system diagram showing another embodiment of the invention. In the figure, 1 is a compressor, 2 is a speed increaser, 3 is a motor, 4 is an oil reservoir chamber, 5 is a motor chamber, 6 is a seal, 7 is a seal, 8 is a condenser, 9 is an expansion valve, 10
1 is an evaporator, 11 is an oil tank, 12 is an oil pump, 13 is an oil supply pipe, 14 is an oil return pipe, 15 is a pressure equalization pipe, 16 is an expansion valve for cooling the motor, and 17 is a pressure regulating means. In addition, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A refrigeration cycle in which high-pressure refrigerant gas compressed by a compressor is sent to a condenser and liquefied, the pressure is reduced by an expansion valve, the gas is vaporized by an evaporator, and the gas enters the compressor; A centrifugal refrigeration system having a lubrication cycle in which lubricating oil in an oil sump chamber connected to the oil tank enters an oil tank and is sent from the oil tank to a lubricated part connected to the oil sump chamber by an oil pump. A centrifugal refrigeration system characterized in that a part of the high-pressure refrigerant gas compressed by the compressor flows into the oil sump chamber through a pressure regulating means. 2. The centrifugal refrigeration apparatus according to claim 1, wherein the pressure adjustment means is constituted by a capillary reach tube. 3 A refrigeration cycle in which high-pressure refrigerant gas compressed by a compressor is sent to a condenser and liquefied, then depressurized by an expansion valve, vaporized by an evaporator, and enters the compressor, and an oil connected to the compressor. In a centrifugal refrigeration system having a lubrication cycle in which lubricating oil in a reservoir chamber enters an oil tank and is sent from this oil tank to a lubricated part connected to the oil reservoir chamber by an oil pump, the compressor A portion of the compressed high-pressure refrigerant gas is passed through a pressure regulating means and a channel opening/closing means connected in series with the pressure regulating means, and the channel opening/closing means is operated only for the time required to start up the compressor. A centrifugal refrigeration device characterized in that the oil is opened to flow into the oil storage chamber. 4. The centrifugal refrigeration apparatus according to claim 8, wherein the pressure regulating means is composed of a capillary reach tube, and the flow path opening/closing means is composed of an automatic opening/closing valve.