JP3234681B2 - Oil-cooled screw compressor - Google Patents

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 adapted to lubricate a rotor chamber.

[0002]

2. Description of the Related Art Conventionally, an oil-cooled screw compressor shown in FIG. 3 has been known (Related device: Japanese Utility Model Application Laid-Open No. 64-25490). As shown in the figure, an oil separation and 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 separation element 15 is provided at an upper portion in the oil separation and recovery device 14, and an oil reservoir 16 is provided at a lower portion. In addition, the on-off valve 17
Is connected to the drain passage 18 having an oil supply passage 19 and the oil supply passage 19.

The oil supply flow path 19 is divided into two flow paths 21 and 22 by a temperature control valve 20, and one flow path 21 is provided with an oil cooler 23. , 22 is X
They meet at a point and communicate with a rotor chamber, a bearing, a shaft seal, and the like in the compressor body 12. The amount of oil flowing through each of the flow paths 21 and 22 is adjusted by the temperature control valve 20 so that the temperature on the inlet side of the temperature control valve 20 is maintained within a desired range. The drain water deposited in the oil reservoir 16 opens the on-off valve 17 and opens the drain passage 18.
Is discharged from

[0004]

Today, all users tend to save labor and labor, and the same applies to the maintenance of the apparatus. The work of draining the drain water from the bottom of the oil separation and recovery unit 14 is also required. 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 the drain water from collecting in the oil separation / collection unit 14, the temperature in the oil separation / collection unit 14 is set to 75 ° to
It is necessary to keep it at 80 ° C. or higher. That is, the temperature control valve 20
The temperature at the inlet side of the former was about 65 ° C.
It is necessary to maintain the temperature in the range of ° C. to 80 ° C. or more, and the type of the wax must be changed. Conventionally, before the operation of the compressor, an operation of draining the drain water from the bottom of the oil separator / collector 14 has been performed.

Further, by keeping the temperature on the inlet side of the temperature control valve 20 high, there is an advantage that the precipitation of drain water can be prevented, but on the other hand, the lubrication temperature of the rotor chamber in the compressor body 12 increases, and the rotor temperature increases. A problem arises in that the gas in the room is overheated and the performance of the compressor is reduced.
In other words, in order to improve the performance of the compressor, it is considered that the lubrication temperature to the rotor chamber is optimally 45 ° C. to 55 ° C. In this case, the drain water is collected by the oil separation and recovery unit 14. A problem arises in that precipitation occurs, which is contrary to labor saving. The present invention has been made to solve such a conventional problem, and it is possible to prevent the precipitation of drain water in the oil separation and recovery unit without lowering the performance of the compressor, and to eliminate the need for draining operation. It is intended to provide an oil-cooled screw compressor.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an oil separation and recovery device provided in a discharge passage extending from a discharge port of a compressor body to separate and recover oil separated from compressed gas. In an oil-cooled screw compressor provided with an oil supply passage for supplying into a rotor chamber in a compressor body, the oil supply passage is filled into a suction side space in the rotor chamber through an oil cooler. The first flow path portion is branched into a second flow path portion for lubricating without passing through an oil cooler to a discharge port side space portion in a rotor chamber that does not communicate with a discharge port in the compressor body. At the same time, a temperature control valve for controlling the oil amount in each of the flow path portions was provided at this branch point such that the temperature on the inlet side was maintained within a desired range.

[0007]

With the construction as described above, the low-temperature oil cooled by the oil cooler is supplied to the suction-port side space in the rotor chamber, and the oil-cooled space is supplied to 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 and recovery apparatus is maintained at a high temperature at which drain water does not precipitate.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an oil-cooled screw compressor according to a first embodiment of the present invention. Portions common to those in the compressor shown in FIG.
In this embodiment, the oil supply passage 1 is formed by branching into a first passage portion 2 and a second passage portion 3 by a 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-side space in the rotor chamber, the bearing, and the shaft seal. The suction-port-side space may or may not communicate with the suction port of the compressor body 12.

The second flow path section 3 supplies high-temperature oil to the discharge port side space in the rotor chamber which does not communicate with the discharge port in the compressor body 12 without passing through an oil cooler. Things. Since the space communicating with the discharge port has a high pressure and cannot supply oil, the space on the discharge port side is limited to a position that does not communicate with the discharge port. In the compressor having the above-described configuration, the suction gas in the suction port side space in the rotor chamber is cooled by the first flow path portion 2, so that the performance of the compressor is reduced without reducing the suction gas amount. And the temperature of the discharge-side space in the rotor chamber is prevented from becoming too low by the second flow path portion 3, and the inside of the oil separation and recovery unit 14 can be maintained at a high temperature at which drain water does not precipitate. It is formed. Therefore, without reducing the performance of the compressor, the precipitation of drain water in the oil separation and recovery unit 14 is prevented, and the drain removal operation is not required.

FIG. 2 shows an oil-cooled screw compressor according to a second embodiment of the present invention, which is different from the compressor shown in FIG. Are substantially the same except that a bypass flow path 5 having an electromagnetic on-off valve 4 is newly provided. Corresponding parts are denoted by the same reference numerals and description thereof is omitted. Then, in this embodiment, the temperature in the oil separation and recovery unit 14 is low at the time of startup, and all 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 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 flow path extending from the discharge port of the compressor body, In an oil-cooled screw compressor provided with an oil supply passage for supplying into a rotor chamber in a compressor body, the oil supply passage is lubricated into a suction port side space in the rotor chamber via an oil cooler. One flow path portion and a discharge port side space portion in the rotor chamber that does not communicate with the discharge port in the compressor body,
Each of the above-mentioned flow path portions is formed so as to be branched into a second flow path portion to be lubricated without passing through an oil cooler, and at this branch point, the temperature of the inlet side is kept within a desired range. Is provided with a temperature control valve for adjusting the oil amount.

[Brief description of the 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 and recovery device

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04C 18/16 F04C 29/02 331 F04C 29/04

Claims (1)

(57) [Claims] An oil supply passage for supplying oil separated and recovered from compressed gas to a rotor chamber in the compressor body by an oil separation and recovery device provided in a discharge passage extending from a discharge port of the compressor body. In the oil-cooled screw compressor provided with the oil supply passage, the oil supply passage is connected to a suction port side space in the rotor chamber, a first passage portion for injecting oil through an oil cooler, and a discharge port in the compressor body. The discharge port side space in the rotor chamber which does not communicate with the second flow path portion to be lubricated without passing through the oil cooler is formed so as to be branched. An oil-cooled screw compressor characterized by being provided with a temperature control valve for adjusting the amount of oil in each of the flow passage portions so as to be kept within the range.