JPH0454297A - Rust-proof method for inside of oil-free screw compressor main body - Google Patents

Abstract

PURPOSE:To prevent rust from being generated within a compressor main body, by fitting to a compressor discharge piping system, a piping system consisting of, in parallel, an automatic opening/closing valve, a suction tank and an automatic opening/ closing valve, and conducting surely the security of dry compressed air and the reclamation of a suction agent during a compressor operation. CONSTITUTION:As the 1st step, a dry air feed valve 9 and a compressed air introduction valve 10 are closed, and also a vacuum feed valve 14 is opened. Then, water sucked at a suction agent within a suction tank 8 evaporates, as the inside of the tank 8 falls into a vacuum condition by means of a vacuum generator 13. As the 2nd step, the valve 10 is opened simultaneously with the closing of the valve 14, and compressed air is stored within the tank 8, and then, the valve 10 is closed. then, compressed air stored within the tank 8 is stored as dry air whose water is sucked by means of the suction agent. In the 3rd step, the dry air feed valve 9 is opened after a compressor stop, and dried compressed air is fed into the inside of the compressor main body 1, and the compressor main body 1 inside is filled with dry air, and the condition of water being dewed is dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an effective method for preventing rust inside the compressor body of an oil-free screw compressor.

[Conventional technology]

Conventional oil-free screw compressors do not take proactive measures to prevent rust inside the compressor body. This is because the rotor and casing, which are the main parts that make up the compressor body, have a fairly complex shape and require high-precision machining. The problem is that the conditions are far from being acceptable to the market.

The prior art related to the present invention, as shown in Japanese Patent Publication No. 3g-25969, involves alternately feeding compressed air into two types of adsorption tanks filled with adsorbent to take out dry air and regenerate the adsorbent. Devices for continuously extracting dry air are known.

[Problem to be solved by the invention]

As mentioned in the above-mentioned prior art, the main body of an oil-free screw compressor is very expensive, and therefore no active rust prevention measures are taken. For this reason, when the compressor is in continuous operation, there are not many conditions for rust to form inside the compressor body, and there is almost no problem, but when the compressor is stopped, rust remains inside the compressor body. Moisture contained in the air condenses on the rotor and casing surfaces, gradually causing rust. When this rust flakes off for some reason, it gets stuck between the rotors rotating at high speed in a small gap, or between the rotor and the casing, causing many troubles such as locking of the rotor.

An object of the present invention is to provide an oil-free screw compressor that solves the above-mentioned problems of the prior art in an inexpensive manner and has high reliability.

[Means to solve the problem]

In order to achieve the above objectives, a piping system consisting of an automatic on-off valve, an adsorption tank, and an automatic on-off valve is installed in parallel to the discharge piping system consisting of the primary cooler, check valve, and secondary cooler of the oil-free screw compressor. A vacuum generator, typified by an ejector, was attached to the piping after the secondary cooler, and the piping was configured to be connected between the vacuum generator and the adsorption tank via an automatic on-off valve.

[Operation] In the above configuration, operate the compressor, first close the automatic on-off valves installed before and after the adsorption tank, then open the automatic on-off valve installed on the piping connecting the vacuum generator and the adsorption tank. In this state, the vacuum generator creates a vacuum inside the adsorption tank, so the moisture adsorbed on the adsorbent in the adsorption tank is removed and the adsorbent cannot be regenerated. When the adsorbent has been sufficiently regenerated, the automatic on-off valve that was in the open state is closed, and the automatic on-off valve after the adsorption tank is opened to store compressed air in the adsorption tank, and the automatic on-off valve is closed again. The compressed air stored in the adsorption tank has moisture adsorbed by an adsorbent and is stored as dry air.

If this dry compressed air is supplied to the inside of the compressor body by opening the automatic on-off valve in front of the adsorption tank after the compressor is stopped, the inside of the compressor body will be filled with dry air, so dew will condense inside the compressor body. Therefore, the problems with the prior art can be solved.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG.

In Fig. 1, 1 is the main body of the oil-free screw compressor, 2 is the primary cooler 23, which is the check valve, 4 is the secondary cooler, and 5 is the primary cooler 23, which is the check valve.
is a compressed air supply valve, and the discharge piping system is also 6.
7 is an unloader valve, and 7 is a suction filter, and these constitute the suction piping system.

8 is an adsorption tank filled with adsorbent,
A dry air supply valve 9 that can be automatically opened and closed is installed before and after the adsorption tank 8.
and a compressed air inlet valve 10 are installed, respectively, and these piping systems are provided with piping 11. 12 in parallel. Additionally, a vacuum generator 13 is provided between the secondary cooler 4 and the compressed air supply valve 5.
The vacuum generator 13 is connected to the adsorption tank via a vacuum supply valve 14 that can be automatically opened and closed.

The compressor is operated, and the three automatic opening/closing valves shown in FIG. As a first step, the dry air supply valve 9 and the compressed air introduction valve 10 are closed, and the vacuum supply valve 14 is opened. In this state, the interior of the adsorption tank 8 is brought into a vacuum state by the vacuum generator 13, so that the moisture adsorbed on the adsorbent in the adsorption tank 8 evaporates, thereby regenerating the adsorbent. When the adsorbent has been sufficiently regenerated, the vacuum supply valve 14 is closed as a second step, and at the same time the compressed air introduction valve 1 is closed.
0 is opened to store compressed air in the adsorption tank 8, and then the compressed air introduction valve 10 is closed again. The compressed air stored in the adsorption tank 8 is stored as dry air with moisture adsorbed by the adsorbent. In the third step, after the compressor has stopped, the dry air supply valve 9 is opened to supply dry compressed air into the compressor main body 1, and the compressor main body 1 is filled with dry air. Since there is no condition for moisture to condense inside the main body 1, if the steps from the first stage to the third stage explained above are performed automatically every time the compressor is started and stopped, as a result, the inside of the compressor main body 1 will be reduced. Since rust prevention can be ensured, a highly reliable oil-free screw compressor can be provided.

When the compressor is stopped, the compressed air in the front stage of the check valve 3 passes through the unloader valve 6 and is converted to the atmosphere by the suction filter in several tens of seconds, so the dry air is released from the air that is supplied afterwards. effective.

In addition, the size of the adsorption tank 8 is very small, such as the volume in the front stage of the check valve 3, so a volume of about 2Q is sufficient, and the adsorbent packed in the adsorption tank 8 is generally activated alumina, etc. However, if you use an adsorbent such as carbon molecular sieve, it will adsorb not only moisture in the air but also oxygen molecules at the same time, making it dry and providing air with a low oxygen concentration, so the rust prevention effect will be even greater. Become.

In addition, if you close the compressed air supply valve 5 after the compressor stops as shown in Figure 1, there will be no problem, but if this valve is not closed, the air will accumulate in the air tank set up ahead. It is possible that a large amount of compressed air leaks into the compressor main body 1 side, albeit in a very small amount, from the check valve 3, so the price will be somewhat high, but if you use the configuration shown in Figure 2, you will be completely safe. I think so. That is, in FIG. 2, the compressed air supply valve 5 shown in FIG. 1 is replaced with an automatic opening/closing valve 15.

If another automatic on-off valve 16 is installed between this valve and the check valve 3, when the compressor stops, the automatic on-off valve 1
If the valve 5 is closed and the automatic on-off valve 16 is opened, the pressure inside the check valve 3 and the automatic on-off valve 15 becomes atmospheric pressure, which solves the problem.

〔Effect of the invention〕

According to the present invention, by installing a simple and inexpensive device, it is possible to regenerate the adsorbent and secure dry compressed air while the compressor is operating, so that this dry compressed air can be compressed after the compressor is stopped. By supplying it into the compressor body, it is possible to prevent rust from forming inside the compressor body.

[Brief explanation of the drawing]

1 and 2 are flow sheets showing different embodiments of the present invention. 8... Adsorption tank, 9... Dry air supply valve, 10...
Compressed air introduction pipe, 11.12...Piping, 13...Vacuum generator. 14...Vacuum supply valve, 15.16...Automatic opening/closing valve.

Claims (1)

[Scope of Claims] 1. A discharge piping system comprising a primary cooler, a check valve, and a secondary cooler of an oil-free screw compressor, wherein the discharge piping system includes an adsorption tank filled with an adsorbent and the adsorption tank. A piping system with automatic on-off valves that can be automatically opened and closed is installed in parallel before and after the tank, and a vacuum generator is installed on the piping system after secondary cooling, and the connection between the vacuum generator and the adsorption tank is automatically opened and closed. A method for preventing rust inside an oil-free screw compressor main body, characterized in that the piping is configured to be connected through a valve.