JPH0953588A - Oil separation device for oil-cooled compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure clean discharge air by providing a separator tank of a vertically long cylindrical vessel with an inner cylinder in its upper part, a gas inlet on its side surface, and a gas outlet on its upper surface, so that the center line of gas inlet on the side surface in plan view and the radial direction of the axis of the separator tank are offset. SOLUTION: A separator tank 5 is provided with a gas inlet 15 on the side surface of the tank 5, and a gas outlet 16 on its upper surface. The tank is constituted in such a way that, denoting by D the inside diameter of the tank 5, d1 the outside diameter of an inner cylinder 8, and x the distance between the center line of the gas inlet 15 on the side surface in plan view and the axis of the separator tank 5 respectively, d1/D is 0.4 or more, and x/D is 0.2 or more. When the discharge gas of a compressor enters the tank 5, it collides both with the inner circumferential surface of the tank 5 and with the outer circumferential surface of the inner cylinder 8, and the oil content drops due to the swirl between both surfaces. Further, when the remaining oil content enters the fiber layer of an oil separation filter, the particles of oil is aggregatedly grown, and is separated from the discharge gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil separator for an oil-cooled compressor that injects oil into a working chamber.

[0002]

2. Description of the Related Art Conventionally, in an oil-cooled rotary compressor, lubricating oil is injected into the compressor in order to lubricate each part of the compressor and cool the compressed gas. The jetted lubricating oil is mixed in the discharge gas.As described in Japanese Utility Model Publication No. 54-31365, the lower part is provided with an oil tank, the upper part is provided with a cylindrical protective cylinder, and an oil separator with a demister structure. The lubricating oil is separated from the oil, and the discharge gas without oil is discharged.

The lubricating oil collected in the oil tank contains dissolved air bubbles, and when the compressor stops, the air bubbles dissolved in the oil expand as the pressure decreases, and the oil separator tries to fill up. A forming phenomenon occurs. In order to prevent this, in the above-mentioned conventional technique, an opening is provided on the side surface of the protective cylinder so that the inside and outside of the protective cylinder are evenly pressured.

[0004]

The area of the opening of the protective cylinder needs to be large enough to eliminate the pressure difference between the inside and outside of the protective cylinder. When the opening becomes large, the gas in the oil separator becomes large. The discharge gas with a large amount of oil may directly enter from the inlet, which causes a problem that the mist concentration at the outlet of the demister becomes high.

Further, even if there is no pressure difference between the inside and outside of the protective cylinder, if the distance between the oil surface and the demister is insufficient, the oil is immersed in the demister due to forming, and the oil is discharged together with the discharge gas when the compressor is started. There was a problem that the oil was contaminated with oil, and it was impossible to miniaturize the oil separator.

The object of the invention is to ensure clean discharge air.

[0007]

In order to achieve the above object, the present invention provides a separator tank from the discharge side of a compressor,
Oil separation filters are provided separately in this order, and the separator tank is a vertically long cylindrical container, with an inner cylinder on the top, a gas inlet on the side,
A gas outlet is provided on the upper surface, the center of the gas inlet on the projection surface from the side surface and the separator tank are offset in the radial direction, and the oil separation filter is composed of a fiber layer such as glass wool.

[0008]

[Operation] A large amount of oil is contained in the discharge gas of the compressor, and when the discharge gas enters the separator tank, most of the oil is removed due to collision between the inner peripheral surface of the separator tank and the outer peripheral surface of the inner cylinder, and swirling of both surfaces. Drop (primary separation). Further, the remaining oil enters the oil separation filter, and the fine particles of the oil are coagulated and grown by passing through the fiber layer to completely separate the oil from the discharge gas (secondary separation).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an explanatory view of the oil-cooled screw compressor oil separation device of the present invention. A suction filter 3 is provided on the suction side of the compressor body 1 via a suction pipe 2. On the discharge side, a separator tank 5 is provided via a discharge pipe 4, and an oil separation filter 7 is further provided via a connecting pipe 6.
An inner cylinder 8 is concentrically provided on the upper portion of the separator tank 5, and oil 9 is stored on the lower portion. The separator tank 5 is connected to the oil cooler 11 via the oil supply pipe 10, and is further connected to the compressor body 1. Oil separation filter 7
A fiber layer 12 is provided inside, and the bottom of the fiber layer 12 is connected to the suction side of the compressor body 1 via an oil recovery pipe 13.

2 and 3 show a separator tank 5 having a gas inlet 15 on the side surface of the tank 5 and a gas outlet 16 on the upper surface. In these figures, the inner diameter of the tank 5 is D, the outer diameter of the inner cylinder 8 is d1, the inner diameter of the gas inlet 15 is d2, the distance between the center of the gas inlet 15 and the axis of the separator tank 5 on the projection plane from the side is x, and When the distance from the center of the gas inlet 15 to the lower end of the inner cylinder 8 is h2, d1 / D is 0.4 or more, x / D is 0.2 or more, and h2 is 0.5d2 or more. It Further, h1 is about d2 to 2d2.

The operation of the screw compressor thus configured will be described. When the rotor 14 is rotated by an electric motor (not shown), air is sucked into the compressor body 1 through the suction filter 3. The sucked air mixes with the oil injected due to the pressure difference between the separator tank 5 and the compressor body 1, and becomes high pressure air and is discharged to the discharge pipe 4. The injected oil removes the compression heat of air, reduces internal leakage, and lubricates the rotor.

A large amount of oil is mixed in the discharge air, and when entering the separator tank 5, a large oil is generated by collision between the inner peripheral surface of the separator tank 5 and the outer peripheral surface of the inner cylinder 8 and swirling of both surfaces. The particles fall and accumulate in the separator tank 5. Further, when the discharged air contained in the residual oil enters the fiber layer 12 of the oil separation filter 7, the fine particles of oil are coagulated and grown to be completely separated from the air. The oil separated in the fiber layer 12 collects at the bottom of the fiber layer 12, but if left unattended, it causes a so-called re-scattering phenomenon in which it is carried away by the clean air again, and the separation performance of the oil separation filter 7 is significantly increased. Lower. Therefore, the collected oil is the oil recovery pipe 1
It is returned to the suction side of the compressor body 1 through the compressor 3.

The oil 9 accumulated in the separator tank 5 is constantly circulated through the oil cooler 11 and the compressor body 1, and is in contact with the air during that time. Therefore, when the circulating oil contains dissolved air bubbles and the compressed air in the oil tank 5 is released due to, for example, the compressor stopping, the air bubbles expand. The amount of bubbles contained in the circulating oil is about 10% at the maximum in the discharge pressure state, and when the operating pressure ratio is 8, it rises to about twice the oil level of the oil tank. But separator tank 5
Since the oil separation filter 7 and the oil separation filter 7 are separated from each other, the fiber layer 12 is not oiled by forming. Therefore, the oil does not flow out after the oil separation filter 7 in the restart, and clean compressed air is obtained.

The air discharged from the oil separation filter is almost clean, but contains a few PPM of oil when viewed microscopically. The outlet mist concentration of the oil separation filter is influenced by the inlet mist concentration of the oil separation filter, and there is a limit to the inlet mist concentration of the oil separation filter in order to allow the mist concentration of usable air. If the capacity of the separator tank is sufficient, it will be below this limit value even if there is no offset in the inner cylinder or gas inlet, but these are necessary conditions for downsizing the separator tank.

Generally, in an oil separation filter composed of a fiber layer such as glass wool, it is necessary to set the inlet mist concentration of the filter to several thousand PPM or less in order to set the outlet mist concentration of the filter to several PPM. Therefore, in a small-sized separator tank, it is necessary to improve the efficiency of primary separation by optimizing the gas inlet and outlet positions of the separator tank and the internal structure of the tank.

FIG. 4 is a graph showing the relationship between the inner cylinder diameter (d1 / D) and the outlet mist concentration of the oil separation filter, obtained from an experiment using the gas inlet offset (x / D) as a parameter. Further, when the minimum values of the respective diagrams in FIG. 4 are plotted, the result as shown in FIG. 5 is obtained. From FIGS. 4 and 5, it is understood that the value of d1 / D is 0.4 or more and the value of x / D is 0.2 or more in order to obtain clean compressed air of several PPM or less. d
The upper limit of 1 / D is about 0.8 because the discharge air passage is secured. The upper limit of x / D is d2 / 2D, which is the maximum offset. Further, in FIG. 6, the longer the distance h2 from the gas inlet to the lower end of the inner cylinder, the better the separation efficiency, but the difference is small, and h2 / d2 of about 1 to 3 is sufficient.

[0018]

According to the present invention, the compressed air in the separator tank is released when the compressor is stopped, and the oil is not soaked in the filter layer even when forming occurs, and when the compressor is restarted. Also, clean compressed air can be obtained. Further, primary separation of air and oil is large in a small separator tank, and compressed air of several PPM or less can be obtained even during normal operation by the secondary separation of the oil separation filter.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an oil separation device of an oil-cooled screw compressor according to the present invention.

FIG. 2 is a vertical sectional view of a separator tank of the oil separation device.

3 is a sectional view taken along line AA of FIG.

FIG. 4 is a diagram showing a relationship between d1 / D and mist concentration.

FIG. 5 is a diagram showing a relationship between x / D and mist concentration.

FIG. 6 is a diagram showing a relationship between h2 / d2 and mist concentration.

[Explanation of symbols]

5 ... Separator tank, 7 ... Oil separation filter, 8 ... Inner cylinder, 12 ... Fiber layer, 15 ... Gas inlet, 16 ... Gas outlet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukazu Aoki 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Hitachi, Ltd., Air Conditioning Systems Division (72) Masaaki Toda 390 Muramatsu, Shimizu City, Shizuoka Hitachi Shimizu Engineering Co., Ltd. In the company

Claims (3)

[Claims] 1. An oil-cooled compressor equipped with an oil separator for injecting oil into the working chamber of the compressor from the outside and separating gas and oil on the discharge side, wherein a separator tank is provided from the discharge side of the compressor,
An oil separation filter is provided in this order, and the separator tank is a vertically long cylindrical container provided with an inner cylinder on the upper side, a gas inlet on the side surface, and a gas outlet on the upper surface, the inner diameter of the separator tank is D, the inner cylinder diameter is d1, from the side surface. When the distance between the center of the gas inlet and the axis of the separator tank on the projection plane of x is x, d1 / D
Is 0.4 or more and x / D is 0.2 or more. 2. The oil separation device for an oil-cooled compressor according to claim 1, wherein the oil separation filter is composed of a fiber layer such as glass wool. 3. The oil separation device for an oil-cooled compressor according to claim 1, wherein the separator tank and the oil separation filter are separately provided and connected by a pipe.