JPH0735067A - Oil-cooled screw compressor - Google Patents

Abstract

PURPOSE:To provide an oil-cooled screw compressor with which the eduction of drain water in an oil separator/collector is prevented and which eliminates necessity for draining works with no risk of impairing the performance of the compressor. CONSTITUTION:Oil is separated and collected from the compressed gas by an oil separator/collector 14 furnished in a discharge path 13 which extends from the discharge port of the body 12 of compressor, and an oil supply path 1 to supply this collected oil to the rotor chamber in the compressor body 13 is provided with the first path section 2 to inject oil into the suction port side space in the rotor chamber through an oil cooler 23 and the second path section 3 which, without interposition of the oil cooler 23, injects the oil into the discharge port side space in the rotor chamber out of communication to the discharge port in the compressor body 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-cooled screw compressor for lubricating a rotor chamber.

[0002]

2. Description of the Related Art Conventionally, an oil-cooled screw compressor shown in FIG. 3 is known (related invention: Japanese Utility Model Laid-Open No. 64-25490). As shown in the figure, an oil separation / recovery device 14 is provided in a discharge passage 13 extending from a discharge port of a compressor body 12 that rotatably accommodates a pair of male and female screw rotors 11 that mesh with each other. An oil separating element 15 is provided in the upper part of the oil separating and collecting device 14, and an oil reservoir 16 is provided in the lower part. Further, the opening / closing valve 17 is provided in the oil sump portion 16.
The drainage removal flow path 18 having the above is connected to the oil supply flow path 19.

The oil supply flow passage 19 is divided into two flow passages 21 and 22 by a temperature control valve 20, an oil cooler 23 is provided in one flow passage 21, and the two flow passages 21 are provided. , 22 is X
They join at a point and communicate with the rotor chamber, bearing, shaft seal portion, etc. in the compressor body 12. The temperature control valve 20 adjusts the amount of oil flowing in each of the flow paths 21 and 22 so that the temperature on the inlet side of the temperature control valve 20 is maintained within a desired range. Further, the drain water deposited in the oil sump 16 opens the on-off valve 17 to open the drain drain passage 18
Emitted from.

[0004]

Today, any user has a strong tendency to save labor and labor, and the same applies to the maintenance of the device, and the work of draining the drain water from the bottom of the oil separation and recovery unit 14 is performed. There is a strong demand for eliminating the need. For example, when the discharge pressure of the compressor body 12 is 7 atg, in order to prevent drain water from accumulating in the oil separation / recovery device 14, the temperature in the oil separation / recovery device 14 is set to 75 ° ~.
It is necessary to keep the temperature above 80 ° C. That is, the temperature control valve 20
The temperature at the inlet side of the conventional is about 65 ° C.
It is necessary to keep the temperature above 80 ° C to 80 ° C, and it is necessary to change the type of wax. Incidentally, conventionally, a work of draining drain water from the bottom of the oil separation and recovery unit 14 has been performed before the operation of the compressor.

Further, by keeping the temperature on the inlet side of the temperature control valve 20 high, there is an advantage that drain water can be prevented from precipitating, but on the other hand, the temperature of lubricating the rotor chamber in the compressor body 12 becomes high, and the rotor chamber becomes hot. The gas in the room is overheated, which causes a problem that the performance of the compressor is deteriorated.
In other words, in order to improve the performance of the compressor, it is considered that the oiling temperature to the rotor chamber is optimally 45 ° to 55 ° C. In this way, the drain water is collected in the oil separation / recovery device 14. There is a problem in that it is deposited and runs counter to labor saving. The present invention has been made to solve the problems of the related art, without draining the performance of the compressor, it is possible to prevent the precipitation of drain water in the oil separation and recovery device, and drain work is unnecessary. It aims to provide an oil-cooled screw compressor.

[0006]

In order to solve the above-mentioned problems, the present invention provides an oil separated and recovered from a compressed gas by an oil separation and recovery device provided in a discharge passage extending from a discharge port of a compressor body. An oil-cooled screw compressor having an oil supply passage for supplying the oil to the rotor chamber in the compressor body, the first passage portion for injecting oil into the suction port side space in the rotor chamber via an oil cooler; A second flow passage portion for injecting oil is formed in the oil supply flow passage in the space on the discharge port side in the rotor chamber that does not communicate with the discharge port in the compressor body, without an oil cooler.

[0007]

With the above structure, the low temperature oil cooled by the oil cooler is supplied to the suction port side space in the rotor chamber, and the oil cooling process is performed in the discharge port side space in the rotor chamber. High temperature oil is supplied without passing through the vessel, and the temperature in the oil separation / recovery vessel can be maintained at a high temperature at which drain water does not precipitate.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an oil-cooled screw compressor according to a first embodiment of the present invention, and parts common to those of the compressor shown in FIG.
In this embodiment, the oil supply passage 1 is formed by branching into the first passage portion 2 and the second passage portion 3 by the temperature control valve 20. An oil cooler 23 is provided in the first flow path portion 2,
The oil cooled by the oil cooler 23 can be injected into the suction port side space in the rotor chamber, the bearing, and the shaft seal portion. This suction port side space may be communicated with the suction port of the compressor body 12, or may not be communicated with the suction port.

The second flow path portion 3 supplies the oil of high temperature to the space on the discharge port side in the rotor chamber, which does not communicate with the discharge port in the compressor body 12, without an oil cooler. It is a thing. Since the pressure in the space communicating with the discharge port is high and oil cannot be supplied, the space on the discharge port side is limited to a position that does not communicate with the discharge port. In the compressor configured as described above, since the suction gas in the suction port side space in the rotor chamber is cooled by the first flow path portion 2, the suction gas amount does not decrease and the performance of the compressor deteriorates. The second flow path portion 3 prevents the temperature of the discharge side space in the rotor chamber from becoming too low, and keeps the oil separation / collector 14 at a high temperature at which drain water does not precipitate. Has been formed. Therefore, the drain water is prevented from precipitating in the oil separation / recovery device 14 without degrading the performance of the compressor, and the drain removal work is unnecessary.

FIG. 2 shows an oil-cooled screw compressor according to a second embodiment of the present invention. The compressor shown in FIG. 1 is between the first flow passage portion 2 and the second flow passage portion 3. Other than that the bypass flow path 5 having the electromagnetic on-off valve 4 is newly provided, the other parts are substantially the same, and corresponding parts are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, the temperature inside the oil separation / collector 14 is low at the time of startup, and the oil is guided to the second flow path portion 3 by the temperature control valve 20, but the opening / closing valve 4 is opened only at the time of startup. Oil is guided from the second flow path 3 to the first flow path 2 via the bypass pipe flow path 5 so that the oil can be smoothly operated at the time of startup.

[0011]

As is apparent from the above description, according to the present invention, the oil separated and recovered from the compressed gas by the oil separation and recovery device provided in the discharge passage extending from the discharge port of the compressor body is In an oil-cooled screw compressor provided with an oil supply passage for supplying into a rotor chamber in a compressor body, a first passage portion for injecting oil into a suction port side space in the rotor chamber via an oil cooler; A second flow passage portion for injecting oil is formed in the oil supply flow passage in the space on the discharge port side in the rotor chamber that does not communicate with the discharge port in the main body of the machine, without an oil cooler. Therefore, the low-temperature oil cooled by the oil cooler is supplied to the inlet side space in the rotor chamber, and the high-temperature oil is supplied to the discharge port side space in the rotor chamber without passing through the oil cooler. As a result, the temperature inside the oil separation / recovery device can be maintained at a high temperature at which drain water does not precipitate, and it is possible to prevent the precipitation of drain water in the oil separation / recovery device without degrading the performance of the compressor. This has the effect of eliminating the need for drainage work.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an oil-cooled screw compressor according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of an oil-cooled screw compressor according to a second embodiment of the present invention.

FIG. 3 is an overall configuration diagram of a conventional oil-cooled screw compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil supply flow path 2 1st flow path part 3 2nd flow path part 12 Compressor main body 13 Discharge flow path 14 Oil separation collection device

Claims (1)

[Claims] 1. An oil supply passage for supplying the oil separated and recovered from the compressed gas by an oil separating and collecting device provided in a discharge passage extending from the discharge opening of the compressor body into a rotor chamber in the compressor body. In the provided oil-cooled screw compressor, the first flow path portion for injecting oil into the inlet side space in the rotor chamber via the oil cooler and the rotor chamber in the rotor chamber that does not communicate with the discharge port in the compressor body An oil-cooled screw compressor, characterized in that a second flow passage portion for oil injection is formed in the oil supply flow passage without interposing an oil cooler in the discharge port side space portion.