Gas separation: processes – Deflecting – Centrifugal force
Reexamination Certificate
2002-09-17
2004-11-23
Chiesa, Richard L. (Department: 1724)
Gas separation: processes
Deflecting
Centrifugal force
C055S385300, C055S403000, C055S406000, C055S407000, C055SDIG001, C060S311000
Reexamination Certificate
active
06821319
ABSTRACT:
The present invention relates to a method and an apparatus for cleaning of gas, by means of centrifugal force, from solid or liquid particles suspended in the gas and having a larger density than the gas. The invention is intended for use above all in connection with cleaning of so called crankcase gases, i.e. gases formed in a combustion engine, from particles in the form of oil and/or soot. Alternatively, however, it may be used in other connections.
More closely the invention concerns cleaning of gas in a way such that the gas is conducted through a chamber, which is delimited by a stationary housing, and is caused to rotate in the chamber by means of a rotor kept in rotation around a rotational axis, the particles by upcoming centrifugal force being separated from the gas and thrown towards the stationary housing.
An apparatus for cleaning of gas in this way is known for instance through each one of the patents DE 35 41 204 A1 and DE 43 11 906 A1, which describe cleaning of crankcase gases coming from a combustion engine.
Thus, DE 35 41 204 A1 shows an apparatus of this kind, in which the rotor is formed as a turbine or pump wheel, which is adapted to be brought into rotation by gas to be cleaned entering from below into said chamber. The gas to be cleaned is caused to flow through the turbine or pump wheel from its centre to its periphery, where it leaves the turbine or pump wheel, rotating at the same speed as this wheel. Particles are separated from the gas rotating in the chamber by centrifugal force, and cleaned gas leaves the chamber through an outlet at the upper part thereof. Particles separated from the gas deposit onto the surrounding wall of the chamber, liquid particles coalescing on the surrounding wall and liquid, thereafter, running down it and further out through an outlet situated at the bottom of the chamber.
DE 43 11 906 A1 shows a similar apparatus for cleaning of crankcase gases, in which the rotor is adapted to be driven by means of pressurized lubricating oil coming from the combustion engine, the crankcase gases of which are to be cleaned in the apparatus. The driving lubricating oil is supplied to the rotor at its centre and leaves the rotor through tangentially directed outlets situated at a distance from the rotational axis of the rotor. The rotor constitutes in itself, in this case, a device for cleaning of the driving lubricating oil. The cleaned lubricating oil is released in the lower part of the chamber, through which the crankcase gases shall pass in order to be cleaned, and is returned therefrom to the lubricating oil system of the combustion engine. The crankcase gases are caused to pass axially through a narrow space delimited in the chamber between the rotor and the surrounding stationary housing. Gas rotating in the space is freed from particles suspended therein, which particles deposit onto the inside of the stationary housing, where liquid particles coalesce and liquid thus formed, thereafter, flows towards an outlet.
The two above described known apparatuses for cleaning of crankcase gases have rather a poor efficiency when it comes to separation of particles from a through flowing gas.
The object of the present invention primarily is to accomplish a method of cleaning gases, particularly crankcase gases, which is substantially more effective than the above described gas cleaning methods. It is suggested that a certain previously known technique, other than the one mentioned above for cleaning of crankcase gases, is utilised and improved.
Thus, it is suggested, in accordance with what has initially been said, that
a rotor is kept rotating around a rotatonal axis in a chamber delimited by a stationary surrounding wall, which rotor comprises a stack of conical separation discs arranged coaxially with each other and concentrically with said rotational axis, the separation discs being provided with radially outer surrounding edges,
the gas to be cleaned is conducted through interspaces formed between the separation discs from gas inlets to gas outlets situated at differently large distances from the rotational axis of the rotor, so that the gas is caused to rotate with the rotor and the particles, as a consequence of upcoming centrifugal force, are brought into contact with the insides of the separation discs, and
separated particles by the rotation of the rotor are caused first to move a distance in contact with the separation discs substantially along the generatrices thereof towards said surrounding edge and then are thrown from the separation discs towards said surrounding wall.
Technology of this kind is previously known for instance through U.S. Pat. No. 2,104,683 and U.S. Pat. No. 3,234,716. In each one of these patent specifications it is described how particles having been brought into contact with the insides of the conical separation discs are moved by means of centrifugal force towards the surrounding edges of the separation discs.
U.S. Pat. No. 2,104,683 describes (with reference to
FIG. 2
) that particles in the areas of the radially outermost parts of the separation discs are influenced substantially only by centrifugal forces and move substantially along the generatrices of the separation discs, i.e. in straight paths along radii drawn from the rotational axis of the rotor, whereas particles in the areas of the radially inner parts of the separation discs also and to a very large degree are influenced by flowing gas and, thereby, move in a direction forming an angle with these generatrices. The flowing gas may move substantially freely between the separation discs and may adopt a flow direction determined by among other things the speed by which the gas enters the interspaces between the separation discs and the degree of influence from the rotating separation discs.
U.S. Pat. No. 3,234,716 describes (with reference to the
FIGS. 3 and 4
) how particles are separated in the interspaces between conical separation discs. After having got into contact with the insides of the separation discs the separated particles move substantially radially outwardly from the rotational axis of the rotor towards the surrounding edges of the separation discs.
For improvement of the separation efficiency upon use of this previously known technique it is suggested according to the invention
that separated particles moving in contact with the separation discs substantially along the generatrices thereof are caught and conducted, together with other particles caught in a similar way, further towards the said surrounding edges of the separation discs along paths forming an angle with said generatrices and
that separated particles are caused to leave said paths and are thrown from the separation discs substantially only in limited areas spaces from each other along the surrounding edges of the respective separation discs.
The improvement hereby obtainable is that particles which have once been separated from the gas have increased possibilities in comparison with use of the previously known technology to remain separated from the gas and, thus, not to be entrained again by gas flowing at a large velocity through the space through which the particles have to pass on their way from the rotor to the surrounding stationary surrounding wall. Thus, the particles are collected by means of guiding or conducting members, after which they are conducted further on by means of the centrifugal force towards the surrounding edges of the separation discs while being agglomerated or coalesced to larger particles. In an agglomerated form or as relatively large drops the separated particles are then thrown towards the stationary surrounding wall in limited areas distributed along the surrounding edges of the separation discs, whereas between such areas spaces are left for gas flow into or out of the interspaces between the separation discs.
The gas to be cleaned may be brought to flow between the separation discs either in a direction from or in a direction towards the rotational axis of the rotor. It is preferred that the flow is taking place in the direction
Borgström Leonard
Carlsson Claes-Göran
Franzen Peter
Inge Claes
Lagerstedt Torgny
Alfa Laval AB
Chiesa Richard L.
McCormick Paulding & Huber LLP
LandOfFree
Method and an apparatus for cleaning of gas does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and an apparatus for cleaning of gas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and an apparatus for cleaning of gas will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3340058