JPS62210281A - Underwater screw compressor - Google Patents

Abstract

PURPOSE:To make the start safe and smooth by making every groove-shaped working space formed at every groove of a screw always capable of communicating with both an auxiliary outlet and a high pressure gas outlet and discharging water in a compressor to a separation tank before the start. CONSTITUTION:Every groove-shaped working space formed at every groove 31 of a screw 27 is capable of communicating with both an auxiliary outlet 21 and a high pressure gas outlet 25. Accordingly, when a valve 18 between a suction pipe 3 and a compressor 1 and a valve 19 between a compressed air source 20 and a separation tank 5 are closed, a water supply valve 15 is opened, and a 3-way valve 17 is changed over to introduce high pressure air in the compressed air source 20 to the high pressure gas outlet 25 before starting a compressor 1, the high pressure air enters every groove-shaped working space to open the auxiliary outlet 21. Since water is removed by discharging from an outlet chamber 24 to the separation tank 5, the inside of the compressor is brought to a condition where little water is left, making safe and smooth start possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a submersible screw compressor that is installed and used underwater. Here, the screw compressor has 2
It includes both a shaft type and a single shaft type (a coneworm type in which at least one gate rotor is connected to one screw shaft).

[Prior art]

In the case of submersible screw compressors operated underwater,
Water may fill the working space within the casing during the shutdown period. If you try to start the engine in this state, water is incompressible, so there is a risk that it will generate extremely high pressure and cause damage, and you will not be able to start the engine in this state. To deal with this, it has been considered to open an auxiliary discharge port to relieve the pressure when the pressure in the working space exceeds that, thereby preventing the occurrence of abnormally high pressure.

[Problem that the invention seeks to solve]

However, even in such a case, when draining the water filled in the casing, the water is about 1000 times as strong as air.
A large amount of power is required to pump water with specific gravity, and additional power is also required to open the auxiliary discharge hole, which is set to be closed during normal operation, and discharge the water. This was accompanied by the problem of increasing the size of the device.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a submersible screw compressor that can be started while being filled with water, so that the capacity of the prime mover does not need to be increased.

[Means for solving problems]

The present invention, as a means to solve the above problems,
A water injection type screw compressor that houses a screw shaft in a casing having a suction port and a discharge port and injects water into a compression working space, and a submersible screw compressor that has a water supply route for injection. a high-pressure gas supply path connected to the high-pressure gas source and opening in the casing with a plurality of high-pressure gas outlets, facing the compression working space, into which the high-pressure gas is guided. A plurality of auxiliary discharge ports with a pressure adjustment mechanism are provided, which open when the pressure exceeds a predetermined limit pressure to communicate the compression working space with another space, and each groove shape formed for each groove of the screw shaft is provided. The auxiliary discharge port, the discharge port, and the high-pressure gas outlet are arranged so that all of the compression working space can always communicate with the auxiliary discharge port or any one of the discharge ports and the high-pressure gas outlet. An object of the present invention is to provide a submersible screw compressor characterized by:

[For production]

By having the above configuration, the present invention guides the high pressure gas from the high pressure gas source to the working space without rotating the compressor even if the working space is filled with water at startup, and each The water in the groove-like working space can be removed from the discharge port or the auxiliary discharge port, and safe and smooth startup is possible without increasing the capacity of the motor for driving the compressor.

〔Example〕

Embodiments of the present invention will be described using an example of a single-shaft coneworm type screw compressor in which two gate rotors mesh with each other on both sides of one screw shaft.

In Fig. 1, 1 is a screw compressor placed underwater, which is driven by a driving force R2 such as a motor, which draws air above the water surface through a suction pipe 3 and discharges it through a discharge duct 4. Connected to the tank 5, the water stored in the separate tank 5 passes through the valve 19 and water injection pipes 6a and 6b under the pressure of the discharged air, and enters the working space of the compressor 1 for cooling, sealing, lubrication, etc. Injected.

The injected water is discharged together with air into the separate tank 5, separated from the air by gravity and separator tough, stored in the separate tank 5, and circulated. The air separated from the water passes through a check valve 8, a discharge pipe 9, and a diffuser plate 10.
Sprayed into the water.

Since the water level in the separate tank 5 changes due to evaporation, condensation, infiltration, etc., level switch 1 is used to keep it constant.
1 to detect the water level and perform water level control. That is, when the water level rises above a predetermined level, the drain valve 12 is opened by the operation of the level switch 11, and the water in the separate tank 5 is discharged into the water via the drain valve 2, the check valve 13, and the drain pipe 14. Ru. When the water level falls below a predetermined level, the level switch 11
The water supply valve 15 opens by the operation. An external water supply source is connected to the water supply pipe 16a, and the three-way valve 17 is normally connected to the water supply pipe 16a.
16b are connected to each other, water from the external water supply source is supplied into the working space of the compressor 1 through the water supply pipe 16b, the water supply valve 15, and the injection pipe 6b, which serve as a replenishment route for injection water. Ru.

20 is a compressed air source as a high pressure gas source, and a three-way valve 1
By switching 7, it is brought into communication with the water supply pipe 16b.

When discharging the water filled in the compressed Jal for startup, etc., close the valves 18 and 19, connect the external compressed air source 20 to the water supply pipe 16b by switching the three-way valve 17, and turn off the water supply. The valve 15 is opened regardless of the signal from the level switch 11 (at this time, the drain valve 12 is opened by the signal from the level switch 11. Therefore, the opening of the injection pipe 6b to the casing and the communication between the working space and the discharge duct 4) As will be described later, high-pressure air from the compressed air aZO enters the working space from the water injection pipe 6b and pushes out the filled water into the separate tank 5.The compressed air further enters the separate tank 5. When the water level drops to a predetermined reference water level, the drain valve 12 is closed by the action of the level switch 11.At this time, almost no water remains in the working space of the compressor jal, and the compressor 1 is immediately turned off. It is now safe to start.

The structure of the compressor 1 is shown in FIG. 2 and FIG. 3, which is an exploded view.

29 is a casing, and there is one screw 2 in it.
7 is rotatably supported. 28 is on both sides of the screw 27 (only one is shown in the figure. The other one is on both sides of the screw 27
It is a gate rotor that rotates by meshing with the groove (located on the other side of the As a result, the volume of the groove-shaped working space partitioned by the land 32 and the gate rotor 28 is reduced and compressed, and finally the fluid is discharged from the discharge port 26 into the discharge chamber 24.

25 is a high-pressure gas outlet that allows high-pressure air to flow out from the compressed air source 20 in order to eliminate water in the compressor 1, and also serves as an inlet for water for circulation and replenishment; The holes are opened in the casing 29 and arranged at the same pitch as the grooves 31 as shown in FIG. 3, and the diameter of the opening hole is larger than the width of the land 32 as shown in FIG. The high pressure gas discharge port 25 communicates with either a31.

Reference numeral 21 denotes an auxiliary discharge port, which is normally closed by a valve body 22 biased by a spring 23, and opens when a predetermined limit pressure is applied. A plurality of auxiliary discharge ports 21 are provided and open in the casing 29, and as shown in FIG. The diameter of the opening hole of the auxiliary discharge port 21 is larger than the width of the land 32, and when it is opened, it is always connected to either groove 31.
The discharge chamber 24 also communicates with the discharge chamber 24.

The auxiliary discharge port 21 is configured to open when compressed air from the compressed air source 20 is introduced from the high pressure gas outlet 25 and the pressure in the working space becomes high.

In this way, all of the groove-like working spaces formed for each groove 31 of the screw 27 can always communicate with either the auxiliary discharge port 21 or the discharge port 26 and the high-pressure gas outlet 25. , prior to starting the compressor 1, the valve 18.
19 is closed, the water supply valve 15 is opened, and the three-way valve 17 is switched to guide high pressure air from the compressed air source 20 to the high pressure gas outlet 25. The high pressure air enters each groove-shaped working space and flows through the auxiliary discharge port 21.
is opened to remove water from the discharge chamber 24 to the separate tank 5, and almost no water remains in the compressor 1, making it possible to start safely and smoothly.

Even if the auxiliary discharge port 21 is filled with water during operation, it opens before the pressure becomes high and the water is discharged into the discharge chamber 2.
4 to prevent equipment damage.

In the above embodiment, the water supply pipe 16b is the water supply route for injection.
, the water supply valve 15, the water injection pipe 6b, and the cavity pressure gas outlet 25 are shared with the high-pressure gas passage for high-pressure air from the compressed air tX20, and are switched by the three-way valve 17, but the high-pressure gas passage Separately, an injection water replenishment path may be provided, and water may be injected into the working space from an injection port that is separate from the high-pressure gas outlet 25 and is common to the circulation water injection port.

Although a single-shaft cone worm type screw compressor has been described above, a two-shaft screw compressor also exhibits similar effects.

Further, in the above embodiment, the auxiliary discharge port 25 is connected to the casing 29.
Although the example in which the opening is opened on the inner surface of the screw 27 is shown, the opening is opened in the groove 31 of the screw 27 to face the working space, and a communication passage is provided by penetrating the shaft end of the screw 27 and a part of the casing 29. It may be configured to communicate with the discharge chamber 24.

〔Effect of the invention〕

According to the present invention, when starting a compressor, water filling the operating space is effectively removed, and furthermore, the submersible system enables smooth and safe starting without increasing the capacity of the driving motor of the compressor. It is possible to provide a screw compressor for use in the present invention, which has extremely great practical effects.

[Brief explanation of drawings]

The drawings relate to an embodiment of the present invention, and Fig. 1 is a flow diagram of the entire device. Fig. 2 is a vertical cross-sectional view of the compressor. Fig. 3 is a developed view of the screw surface. Fig. 4 is a diagram showing the land and high-pressure gas. It is an explanatory view showing dimensional relationship with an outlet. 1... Compressor 17... Three-way valve 2...
Prime mover 18... Valve 3... Suction pipe
19...Valve 4...Discharge duct 20.
...Compressed air source 5...Separate tank 22...
Valve body 6a, 6b...Water injection pipe 23...Spring 7...
・Separator 24...Discharge chamber 8...Check valve 25...High pressure gas outlet 9...Discharge pipe
26...Discharge port 10...Diffuser plate
27...Screw 11...Level switch 2
8... Gate rotor 12... Drain valve 29
...Casing 13...Check valve 3o...
・Suction port 14...Drain pipe 31...Groove 15
... Water supply valve 32 ... Land 16a, 16
b-...Water pipe patent applicant Ebara Corporation Representative Patent attorney Pharmacist Yori Nejiru 1) Kojibe
Tadashi Takagi 1st plan 1. ! :13 i4 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A water-injection type screw compressor in which a screw shaft is housed in a casing having a suction port and a discharge port, and water is injected into a compression working space, and an underwater injection water supply path. A screw compressor for use in a screw compressor, comprising: a high-pressure gas source; and a high-pressure gas supply path connected to the high-pressure gas source and opening in the casing with a plurality of high-pressure gas outlets, facing the compression working space; When the high-pressure gas is introduced into the chamber and exceeds a predetermined critical pressure, the pressure gas is opened and the compression working space is communicated with another space.
A plurality of auxiliary discharge ports with a pressure adjustment mechanism are provided, and all of the groove-shaped compression working spaces formed for each groove of the screw shaft are always connected to one of the auxiliary discharge ports, or one of the discharge ports, and A submersible screw compressor, characterized in that the auxiliary discharge port, the discharge port, and the high-pressure gas outlet are arranged at a position where they can communicate with a high-pressure gas outlet. 2. The underwater screw compressor according to claim 1, wherein the auxiliary discharge port opens on the inner surface of the casing. 3. The underwater screw compressor according to claim 1, wherein the auxiliary discharge port opens in a groove portion of the screw shaft. 4. The underwater screw compressor according to claim 1, wherein the injection water supply path is switchably connected to the high-pressure gas supply path.