Rotary kinetic fluid motors or pumps – Bearing – seal – or liner between shaft or shaft sleeve and... – Seal
Patent
1996-05-17
1998-07-14
Kwon, John T.
Rotary kinetic fluid motors or pumps
Bearing, seal, or liner between shaft or shaft sleeve and...
Seal
415231, 4151742, F04D 2910
Patent
active
057794456
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a pump for pumping a high-purity liquid, such as a high-purity chemical or ultrapure water used in a VLSI (very large scale integrated) circuit manufacturing system, without internally producing any trace of dust and, more specifically, to a noncontaminative centrifugal pump provided with a noncontact shaft seal assembly providing an accurate gap to allow a required leakage from the associated system, and having a structure that does not produce dust by abrasion and inhibits foreign matter from entering the casing of the noncontaminative centrifugal pump.
BACKGROUND ART
Generally, in a centrifugal pump for pumping pure water or the like, the entire wetted surfaces of the component parts are finished by grinding to increase impurity eliminating accuracy, and the component parts are formed of materials of an appropriate grade to prevent ionization. However, as regards the shaft seal assembly, a rotating ring is pressed with a spring against a fixed ring in sliding contact, tolerating the production of particles by abrasion as a natural result, and efforts have been entirely devoted to eject the particles produced by abrasion from the system. Although research on materials for forming abrasion-resistant surfaces are made, such materials are expensive and there is little prospect of successfully constructing a noncontaminative pump using such expensive materials.
Such a prior art centrifugal pump has been satisfactorily employed in the field where a liquid of a purity of: a comparatively low level is used. However, the prior art centrifugal pump is unsatisfactory for use in a system that handles a liquid of a very high purity, such as an ultrapure water system, and unsolved problems still reside therein.
It is an object of the present invention to provide a centrifugal pump of an ordinary, simple construction, eliminating plays in bearings by using a hydraulic thrust produced by the pressure produced by an impeller, provided with a shaft seal assembly forming a gap of an adjusted size between slipping surfaces, facilitating maintenance and inspection and conforming to requirements for pumping a high-purity liquid.
DISCLOSURE OF THE INVENTION
The present invention provides a noncontaminative centrifugal pump for pumping a high-purity liquid, such as a high-purity chemical or ultrapure water used in VLSI circuit manufacturing systems without producing any trace of dust. A pump in accordance with the present invention comprises a casing 1, a rotor comprising an impeller 5 and a main shaft 6, and a shaft seal assembly disposed in a portion of the casing 1 through which the main shaft penetrates the casing 1 and comprising a rotating ring 8a that rotates together with the rotor, and a fixed ring 8b disposed fixedly opposite to the rotating ring 8a. The fixed ring 8b is fixed to a seal case 9, and the seal case 9 is fitted in a boss of the casing 1 and connected to the casing 1 by screw thread engagement or the like so as to be movable relative to the casing 1 for positional adjustment to adjust the size of a gap e between the slipping surfaces properly without disassembling the pump while the pump is in operation as well as while the pump is stopped and to be fixed after positional adjustment.
The impeller 5 has main impeller vanes 5a for applying pressure to the liquid with centrifugal force, and outvanes 5b for counterbalancing an axial thrust generated by the produced pressure and acting on the impeller 5. The outside diameter and the shape of the outvanes 5b are designed so that an axial thrust acts in one direction on the impeller 5. This axial thrust biases the main shaft 6 in one direction to remove a play attributable to clearances between the components of a bearing 12, such as a ball bearing, and holds the main shaft 6 stably at an appropriate position to secure stably the gap e between the respective slipping surfaces of the rotating ring 8a and the fixed ring 8b in an appropriate size. The position of the seal case 9 is adjusted properly so that th
REFERENCES:
patent: 963593 (1910-07-01), Legros
patent: 1967316 (1934-07-01), Meeker
patent: 3652180 (1972-03-01), Choquette et al.
Kawamoto Masahiro
Tanimoto Tetsuya
Yokota Hiroshi
Kabushiki Kaisha Yokota Seisakusho
Kwon John T.
LandOfFree
Noncontaminative centrifugal pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Noncontaminative centrifugal pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noncontaminative centrifugal pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1875950