Imperforate bowl: centrifugal separators – With means for exchanging heat – Comprising or including means for cooling
Reexamination Certificate
1999-11-17
2001-05-08
Walker, W. L. (Department: 1723)
Imperforate bowl: centrifugal separators
With means for exchanging heat
Comprising or including means for cooling
C494S015000, C494S039000, C494S041000, C494S046000, C494S083000, C384S467000, C384S476000
Reexamination Certificate
active
06228016
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns a sealing device to separate two openings, which are arranged at a distance from each other in an outer casing of a shaft suspension unit, which is arranged during operation to rotatably support a shaft of a centrifugal separator in at least one bearing, the shaft extending through at least one of said openings into a space surrounding the shaft formed inside the outer casing.
BACKGROUND OF THE INVENTION
In shaft suspension units of this kind the shaft and parts connected thereto and rotating with the shaft during operation entrain the air or other gas, which is located in this space. This air or gas contains oil drops in the form of an oil mist, which is used to lubricate bearings arranged in the shaft suspension unit. By the rotation of the air the air pressure will be different in different parts of the space, which means that the air pressure as a rule is different at the two openings. This causes an often very high air flow in through the one opening and out through the other opening, whereby the oil drops are lost for their purpose and pollute the surroundings of the shaft suspension unit. Furthermore, particles, bacteria etc. might enter the shaft suspension unit and decrease the lifetime of the bearings or create colonies of bacteria.
In U.S. Pat. No. 4,654,023 there is shown a centrifugal separator with a shaft suspension unit, which has an opening through which the shaft of the centrifugal separator extends. At this opening there is arranged a mechanical sealing, which has a sealing element, which is connected to the shaft, and a sealing element, which is connected to a stationary outer casing of the shaft suspension unit, and which effectively prevents air or gas flow through the opening.
However, mechanical sealings of this kind are complicated, expensive and often consume a high effect. Furthermore, they are worn out quickly at the very high number of revolutions of centrifugal separators. Since they are difficult and time consuming to replace this involves high labour and downtime costs.
SUMMARY OF THE INVENTION
The object of the present invention is to accomplish a sealing device of the kind initially described, which separates the two openings and is simple but still it prevents effectively an air flow through the two openings without being worn out and involve high labour and downtime costs.
According to the present invention this is accomplished by providing a sealing device of this kind with a first sealing element connected to the outer casing and a second sealing element connected to the shaft, the sealing elements surrounding the shaft and together dividing the space in two departments connected to one opening each and forming there-between a narrow gap surrounding the shaft with no direct contact with each other, the gap being arranged during operation to prevent a flow of gas between the two departments. One of the sealing elements is provided with at least one channel, which has an opening in the central part of the gap, for the supply of a sealing liquid under pressure to the gap during operation in such a way that sealing liquid flows out of the opening through the gap filled up with sealing liquid in a direction to and out into the two departments.
In a preferred embodiment of the invention the opening of the channel is arranged in a recess surrounding the shaft, the recess being formed in the first sealing element and is open towards the second sealing element.
Hereby a sealing device is accomplished, which effectively prevents airflow through the two openings.
Suitably, the sealing liquid consists of an oil, which continuously is supplied to the shaft suspension unit for the lubrication and/or cooling of the bearing. At least a portion of the oil, which flows out into a department from the gap, is conducted to the bearing located in this department. To accomplish this elements present in this department and rotating with the shaft are used, the elements creating during operation an air circulation conducting the oil in the form of drops to the bearing.
In a special embodiment of the invention it comprises a conduit for return conducting a portion of the oil flowing out into one department from the gap directly to a collecting vessel.
REFERENCES:
patent: 4654023 (1987-03-01), Foldhazy
patent: 6117063 (2000-09-01), Szepessy et al.
patent: 2343506 (1974-04-01), None
patent: 0054502 (1982-06-01), None
patent: 0756897 A1 (1997-02-01), None
patent: 422391 (1935-01-01), None
patent: 361080 (1973-10-01), None
International Search Report.
Kristensen Aksel
Nilsson Sven-Åke
Öhlander Carl Peder
Pitkämäki Jouko
Sandblom Robert
Alfa Laval AB
Fish & Richardson P.C.
Fleming Michael A.
Walker W. L.
LandOfFree
Sealing device for a centrifugal separator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sealing device for a centrifugal separator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sealing device for a centrifugal separator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2537197