Rotary expansible chamber devices – Interengaging rotating members – Like rotary members
Reexamination Certificate
2000-04-14
2001-02-06
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Interengaging rotating members
Like rotary members
C418S206700, C418S142000, C418S144000
Reexamination Certificate
active
06183231
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to rotary pumps and more particularly to gear pumps.
2. Description of the Related Art
Rotary pumps have been developed for a number of different uses, ranging from fire engine apparatus to volumetric dosing of commercially important materials. Rotary pumps may be classified according to structural features of their material propelling elements. One commercially important type of rotary pump is the gear pump, in which one or more pairs of intermeshing gears propel material with their gear teeth. Examples of these types of pumps are given in U.S. Pat. Nos. 1,005,586; 2,176,322; 3,096,719; 3,427,984; 2,967,487, and in a modified, related form in U.S. Pat. Nos. 3,170,408; 3,171,590; and 4,787,831.
Pumps of the above-described type can be employed with a single shaft, with the gear teeth in contact with an appropriately shaped casing, to trap the material to be transported between the gear and the casing. Pumps may also employ a pair of intermeshing gears designed to propel materials between intermeshed teeth. Pumps may be distinguished by the configuration of the gears and may, for example, utilize spur gears as well as screw-type or helical gears.
Regardless of the types of gears employed, design challenges have arisen to minimize leakage of material flowing through the pumps while providing adequate rotational support for the shafts on which the gears are mounted. These and other improvements in gear pumps are constantly being sought. For example, it is desirable in some applications to be able to clean a pump “in place” without requiring the pump to be removed and disassembled at a remote cleaning location.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a gear pump having a pair of intermeshed gears which propel material through the pump.
Another object of the present invention is to provide a gear pump which can be cleaned “in place” to a degree sufficient for commercially important applications.
A further object of the present invention is to provide a gear pump of the above-described type which can be simply and economically manufactured from a minimum of inexpensive parts.
These and other objects of the present invention, which will become apparent from studying the appended description and drawings, are provided in a gear pump having a housing means for defining an internal cavity with a flow entrance and a flow exit communicating with the internal cavity, a first shaft, a first pump gear mounted on the first shaft, a first gear seal carried by the first shaft, a second shaft, a second pump gear mounted on the second shaft, a second gear seal carried by the second shaft, rolling element bearings carried by the housing means so as to be spaced from the first and the second gear seals and so as to mount the first and the second shafts to the housing in intermeshing rotation with one another, first and second housing seals carried by the housing means for mating engagement with the first and the second gear seals, respectively, the first and the second housing seals spaced from the first and the second shafts, respectively.
REFERENCES:
patent: 1005586 (1911-10-01), Webb
patent: 2176322 (1939-10-01), Barrett
patent: 2933047 (1960-04-01), Judkins
patent: 2967487 (1961-01-01), Nagely
patent: 3059584 (1962-10-01), Cottell
patent: 3096719 (1963-07-01), McAlvay
patent: 3170408 (1965-02-01), Hill et al.
patent: 3171590 (1965-03-01), Bentele et al.
patent: 3173374 (1965-03-01), Beimfohr
patent: 3427984 (1969-02-01), Slevin
patent: 3473476 (1969-10-01), Davidson
patent: 3632240 (1972-01-01), Dworak
patent: 4182602 (1980-01-01), Dworak et al.
patent: 4293290 (1981-10-01), Swanson
patent: 4407645 (1983-10-01), Haigh et al.
patent: 4527966 (1985-07-01), Laumont
patent: 4606712 (1986-08-01), Vondra
patent: 4787831 (1988-11-01), Thomas et al.
patent: 5370514 (1994-12-01), Morita et al.
patent: WO 91/00429 (1991-01-01), None
Standard handbook for Mechanical Engineers, McGraw-Hill Book Company, cover pages and pp. 14-16 (copyright 1967).
A two-page article entitled “Custom Pumps,” a printout from the website of the pump manufacturer. The subject matter shown in the print-out is undated, but is believed to be prior art. Also included, as part of this document, are two pages of enlarged photocopies of the TASKMASTER Pump shown at the bottom of p. 1 of the print-out materials.
A four-page Catalog No. 37 entitled Heavy Duty Gear Pumps: from Northern Division of McNally Industries, Inc. The catalog is undated but is believed to be prior art.
A six-page brochure entitled “Northern Gear Pumps.” The brochure is undated but is believed to be prior art.
Denion Thomas
Kennedy Covington Lobdell & Hickman LLP
Trieu Theresa
United Dominion Industries, Inc.
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