Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-12-07
2001-08-14
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S201100, C418SDIG001
Reexamination Certificate
active
06273693
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a screw compressor, particularly to a screw compressor with a simple construction suitable for efficiently separating oil from discharge gas.
In a conventional screw compressor, as disclosed in Japanese Patent Unexamined Publication No. 10283/1993, a mesh demister is provided in a discharge chamber such that the former includes the whole of a cross section of the latter. There is such a structure that discharge gas discharged from a discharge casing into the chamber is passed through the mesh demister to separate oil contained in the discharged gas.
The efficiency of such a mesh demister separating oil is connected with the speed of gas passing. Either of the speed and flow rate of gas discharged into the discharge chamber has a distribution in a cross section of the chamber. So the gas passes through the mesh demister at uneven speeds and flow rates. More specifically, either of the speed and flow rate near the outlet of a discharge passage of the discharge casing is greater than that of the other parts.
That is, in the whole of the mesh demister, the flow rate in the downstream part of the discharge outlet is great but the speed therein is far from the optimum passing speed for the mesh demister. This causes a problem of remarkably reducing the oil separation efficiency. For solving this problem, some measures were hitherto conventionally taken, e.g., an obstacle plate is provided independently in the chamber or modifying flow passage of discharge gas to change the direction of gas flow and thereby make the flow rate distribution in the chamber even.
However, those measures also have such problems as that the fixing portion of the independent obstacle plate is apt to be damaged, oil scatters again immediately after colliding, and the performance of the compressor deteriorates with an increase in pressure loss due to change of the flow direction.
SUMMARY OF THE INVENTION
The present invention is made in view of the above-mentioned problems, and it is an object of the present invention to provide a screw compressor with a simple construction, high efficiency of separating oil from discharge gas, and a small amount of oil entrained out of the compressor.
A screw compressor as achieves the object of the present invention comprises a casing including at least one pair of male and female rotors engaging with each other, an electric drive motor and a bearing member; a discharge casing provided with a discharge passage for gas and attached to the casing; a discharge chamber provided therein with a main demister for oil separation, a wall of said discharge chamber being joined with the casing such that the discharge chamber contains the discharge casing; and at least one auxiliary demister disposed at a local position immediately behind or near the downstream side of an outlet of the discharge passage so as to be perpendicular to the flow direction of gas at the outlet.
At least one obstacle plate may be disposed on the downstream side of the auxiliary demister.
According to another aspect of the present invention, a screw compressor comprises a discharge casing provided with a discharge passage for gas compressed by male and female rotors engaging with each other; a discharge chamber containing the discharge casing; a main demister disposed in the discharge chamber; and an auxiliary demister disposed on the upstream side of the main demister in the discharge chamber so as to be opposite to an outlet opening of the discharge passage. A member may be disposed on the upstream side of the main demister in order to uniformize each distribution of the speed and flow rate of discharge gas from the discharge passage in the discharge chamber. An obstacle plate may be disposed between the auxiliary and main demisters.
According to another aspect of the present invention, a screw compressor comprises a discharge casing provided with a discharge passage for gas compressed by male and female rotors engaging with each other; a discharge chamber containing the discharge casing; a main demister disposed in the discharge chamber; a frame disposed so as to cover an outlet opening of the discharge passage; an obstacle member disposed in the frame such that discharge gas from the discharge passage collides against the obstacle member; and an auxiliary demister disposed on the upstream side of the obstacle member in the frame. A mesh-like demister is desirably disposed as the main demister so as to contain the whole of a cross section of the discharge chamber.
Other and further objects, features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:
REFERENCES:
patent: 2455297 (1948-11-01), Curtis
patent: 3312387 (1967-04-01), Cassidy
patent: 3408828 (1968-11-01), Soumerai
patent: 3820923 (1974-06-01), Zwiefel
patent: 3820924 (1974-06-01), Cassidy
patent: 4913634 (1990-04-01), Nagata
patent: 5246357 (1993-09-01), Sjoholm
patent: 5494412 (1996-02-01), Shin
patent: 0146098 (1982-09-01), None
patent: 0285689 (1989-11-01), None
patent: 0060416 (1991-02-01), None
patent: 30-026879 (1991-02-01), None
patent: 5-010283 (1993-01-01), None
patent: 5-133334 (1993-05-01), None
patent: 6-042476 (1994-02-01), None
patent: 8-144982 (1996-06-01), None
Patent Abstracts of Japan, vol. 15, No. 155 (M-1104) Apr. 18, 1991.
Patent Abstracts of Japan, vol. 14, No. 60 (M-0931), Feb. 5, 1990.
Patent Abstracts of Japan, vol. 17, No. 282 (M-1420) May 31, 1993.
Hida Takeshi
Nozawa Shigekazu
Urashin Masayuki
Yamazaki Noriyuki
Antonelli Terry Stout & Kraus LLP
Denion Thomas
Hitachi , Ltd.
Trieu Theresa
LandOfFree
Screw compressor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Screw compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Screw compressor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2538209