JP3754236B2 - Oil-free screw compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil-free screw compressor, and more particularly to an oil-free screw compressor that can remove moisture in a supersaturated compressed fluid after operation is stopped and prevent rusting easily (rust prevention). It is.
[0002]
[Prior art]
In a screw compressor, the rotor and casing or rotors rotate without contact while maintaining a slight gap between them, so there is no need to inject lubricating oil into the casing, and it operates as an oil-free compressor. It is widely used for various gas compressions in the chemical industry because there is no concern of lubricating oil entering the fluid. However, since no lubricating oil is used, moisture in the supersaturated compressed fluid may condense during the process of returning the device to room temperature after the operation is stopped, which may cause corrosion and rusting of the compressor and piping.
[0003]
Therefore, as a conventional technique for the purpose of preventing rust, as described in JP-A-4-54297, dry air dried in an adsorption tank by self-pressure is enclosed in a pipe, As described in Japanese Patent Publication No. -128595, some pipes were sealed from a gas cylinder filled with dry air and inert gas.
[0004]
[Problems to be solved by the invention]
In the above prior art, a dedicated pressure vessel such as an adsorption tank or a gas cylinder is required, and since dry air is enclosed in supersaturated air in the compressed air piping, it is not completely dry, but humidity is not reduced. It was something that could only be reduced.
[0005]
Therefore, the object of the present invention is to prevent moisture condensation by reducing the humidity inside the compressor body and piping without installing a dedicated pressure vessel for the purpose of rust prevention. An object of the present invention is to provide an oil-free screw compressor capable of preventing internal rust.
[0006]
[Means for Solving the Problems]
The present invention that achieves the above object is characterized in that, in an oil-free screw compressor, when the high-pressure fluid on the high-pressure side is opened to the atmosphere between the high-pressure side and the low-pressure side piping of the compressor body, A means for evacuating the low-pressure fluid and releasing it into the atmosphere is provided.
[0007]
Yet another aspect of the present invention, the oil-free screw compressor, a check valve between the means to the high pressure side of the pipe and vacuuming of the compressor body is provided, it was or high pressure side of the compressor body Is provided with a means for supplying a rust preventive or dry gas to the low pressure side pipe, and when releasing the high pressure fluid on the high pressure side to the atmosphere, the rust preventive or dry gas is evacuated to prevent the inside of the compressor body and the pipe . To supply rusting agent or dry gas.
[0008]
According to the present invention, the supersaturated air is discharged out of the apparatus by the vacuuming means, and at the same time, the drying effect by the vacuum can be obtained. In addition, according to another feature, the inside of the pipe is in a negative pressure state, so there is an effect of sucking a rust preventive agent or dry gas, etc., and the compressor body and the inside of the pipe can be rusted without installing a pressurized tank. it can.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on an embodiment shown in the drawings.
FIG. 1 is a piping system diagram of an oil-free screw compressor according to the present invention.
FIG. 1 shows an example of a two-stage compression system, in which 1 is a low-pressure stage compressor body composed of an oil-free screw compressor, 2 is a high-pressure stage compressor body composed of an oil-free screw compressor, and 3 is a both-compressor body 1 2 is an intermediate cooler provided in the middle of the pipe connected to 2, 4 is a rear cooler provided on the output side pipe of the high pressure stage compressor body 2 via a check valve 12, and 13 is a high pressure stage compressor body 2. It is an air tank which stores the obtained compressed air.
[0010]
Reference numeral 9 denotes an ejector as a evacuation means provided in a pipe provided with the intermediate cooler 3 via an electromagnetic valve 5, and a supply air port is connected to the rear cooler 4 via an electromagnetic valve 6. Reference numeral 14 denotes an air filter provided in the input side piping of the low-pressure stage compressor body, and reference numeral 15 denotes a controller for the solenoid valves 5 and 6. Reference numerals 7 and 8 are electromagnetic valves for connecting and connecting the cylinders 10 and 11 serving as a rust preventive source or a dry gas source to the compressor bodies 1 and 2 as required. Open / close control is performed together with 5 and 6.
[0011]
In the embodiment of the present invention, when the solenoid valve 5 and the solenoid valve 6 are opened by the controller 15 after the compressor is stopped, the high-pressure compressed air remaining in the rear cooler 4 or the like is ejected from the solenoid valve 6. When the air is supplied to the air 9 and released into the atmosphere, the intermediate cooler 3, the low-pressure compressor main body 1, the high-pressure compressor main body 2, and the low-pressure supersaturated air inside the pipe connecting them are also ejected. Is sucked (evacuated) and released into the atmosphere. Therefore, even if each compressor body 1, 2 and each pipe is at room temperature, there is no supersaturated air already in the pipe and the like, so there is no condensation, and the entire piping system can be kept dry. it can.
[0012]
When the solenoid valves 7 and 8 are opened in accordance with the opening of the solenoid valves 5 and 6 after the compressor is stopped, the source of the rust preventive agent or the dry gas in the cylinders 10 and 11 is compressed because the inside of the pipe is in a negative pressure state. It is sucked into the machine main bodies 1 and 2. As a result, the rust preventive agent or the dry gas is supplied to the compressor main bodies 1 and 2 and the inside of the pipe, so that the rust preventive effect can be improved or the state can be further dried.
[0013]
In addition, you may attach the cylinders 10 and 11 which enclosed the vaporization rust preventive agent through the solenoid valves 7 and 8 in the position which pinches | interposes both compressor main bodies 1 and 2. FIG.
[0014]
Also in this case, when the solenoid valves 7 and 8 are opened in accordance with the opening of the solenoid valves 5 and 6 after the compressor is stopped, the rust preventive agent vaporized inside the cylinders 10 and 11 is compressed because the inside of the pipe is in a negative pressure state. It is sucked into the machine main bodies 1 and 2. Thereby, the rust preventive agent is supplied to the compressor main bodies 1 and 2 and the inside of the pipe, and the rust preventive effect can be improved.
[0015]
The compressed air supply source to the ejector 9 may be the air tank 13 or a dedicated small compressor. In this case, since the compressed air source has a larger capacity than that of the rear cooler 4, if the electromagnetic valves 5, 6, 7 and 8 are intermittently controlled and evacuated, the rust preventive effect is provided for a long time. I can do things.
[0016]
Further, instead of the vaporizing rust preventive cylinders 10 and 11, a dehumidified and dried air cylinder or a dehumidifier may be used. Thus, dry air can be supplied by suction by the ejector 9.
[0017]
The cylinders 10 and 11 and the output side of the solenoid valve 6 may be connected, and high pressure fluid may be pumped into the cylinder. In this case, since the flow velocity in the container is increased, the rust preventive agent is quickly vaporized in the cylinders 10 and 11, and the rust preventing effect can be further enhanced.
[0018]
Although the two-stage screw compressor has been described in the above embodiment, it may be three or more stages, or may be applied to a single-stage screw compressor. Further, the present invention may be applied to a reciprocating type compressor.
[0019]
【The invention's effect】
As described above, according to the present invention, without installing a dedicated pressure vessel or the like for the purpose of preventing rust, the humidity of the compressor body or the inside of the piping is reduced to prevent moisture condensation, and the compressor An oil-free screw compressor capable of preventing rusting inside the main body and piping can be obtained.
[Brief description of the drawings]
FIG. 1 is a piping system diagram of a two-stage compressor using an oil-free screw compressor showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Low pressure stage compressor body 2 ... High pressure stage compressor body 3 ... Intermediate cooler 4 ... Rear coolers 5, 6, 7, 8 ... Solenoid valve 9 ... Ejector 10, 11 ... Cylinder 12 ... Check valve 13 ... Air Tank 14 ... Air filter 15 ... Controller

Claims (2)

In oil-free screw compressors,
A check valve is provided in the high-pressure side pipe of the compressor body, and a high-pressure fluid is discharged into the atmosphere from the high-pressure side pipe downstream of the check valve. An oil-free screw compressor comprising an ejector for evacuating a low-pressure fluid upstream of the check valve by a high-pressure fluid from a pipe and releasing it into the atmosphere.   The low pressure fluid is evacuated from a low pressure side pipe of the compressor main body according to claim 1, and is a high pressure side pipe of the compressor main body. An oil-free screw compressor comprising a gas supply means.

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