Liquid purification or separation – Filter – Within flow line or flow line connected close casing
Reexamination Certificate
2000-02-04
2001-11-20
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
Filter
Within flow line or flow line connected close casing
C210S459000, C210S497300, C169S013000
Reexamination Certificate
active
06318564
ABSTRACT:
TECHNICAL FIELD
This invention relates to pipe line strainers.
BACKGROUND
Pipe line strainers are designed for installation in the water supply connection to automatic sprinkler, water spray deluge, foam-water deluge, or standpipe fire protection systems. The strainers are used in systems where it is necessary or desirable to protect spray nozzles, sprinklers and/or other types of discharge outlets from obstruction by debris that may be present in the water supply. A typical strainer consists of a body that defines a conduit providing water flow from an inlet to an outlet, with a basket screen therebetween to stop debris having dimensions greater than, e.g., about ⅛ inch which may be present in water supply.
SUMMARY
According to the invention, a pipe line strainer comprises a strainer body having an inner body wall surface and defining a flow passageway, and further defining a strainer inlet in communication with the flow passageway and a strainer outlet or outlets spaced from the strainer inlet along the flow passageway in a direction for fluid flow generally from the strainer inlet toward the strainer outlet or outlets. The flow passageway extends generally between the strainer inlet and the strainer outlet or outlets. The pipe line strainer further comprises a strainer basket disposed within the flow passageway between the strainer inlet and the strainer outlet or outlets, the strainer basket comprising a strainer basket wall defining a plurality of through apertures of predetermined cross dimension for flow of fluid from the strainer inlet toward the strainer outlet or outlets. The strainer basket wall divides the flow passageway into a first region of flow upstream of the strainer basket wall and a second region of flow downstream of the strainer basket wall, with fluid transported from the first region for flow to the second region for flow through the plurality of through apertures of the strainer basket. At least one of the first region of flow and the second region of flow has an unequal distribution of flow velocity and/or an unequal distribution of flow volume due to increasing or decreasing incremental flow cross sectional area in the direction for fluid flow.
Preferred embodiments of the invention may include one or more of the following additional features. At least the first region of flow has the unequal distribution of flow, or unequal flow velocity, in part due to decrease in incremental flow cross sectional area in the direction for fluid flow. Preferably, the strainer basket wall has an inclined surface (relative to the inner body wall surface) opposing the strainer outlet, and/or the strainer basket wall is conical in shape with decreasing diameter in the direction for fluid flow or the strainer basket wall has a right conical shape with decreasing diameter in the direction for fluid flow and/or the strainer basket wall is coaxial with the strainer body. The second region of flow has the unequal distribution of flow, in part due to increase in incremental flow cross sectional area in the direction for fluid flow coinciding with at least one of: a direction of increasing volumetric flow within the second region of flow and a direction of increasing flow velocity within the second region of flow. Preferably, the increase in incremental flow cross sectional area coincides with at least the direction of increasing volumetric flow, or the direction of increasing flow velocity, within the second region of flow, the strainer basket wall having an inclined surface (relative to the inner body wall surface) opposing the strainer outlet, and/or the strainer basket wall being conical in shape with decreasing diameter in the direction for fluid flow or the strainer basket wall having right conical shape and/or the strainer basket wall being coaxial with the strainer body. Preferred embodiments of the invention may also include a strainer with an outlet having its axis generally transverse to the axis of the second region for flow. At the junction of the second region and outlet, the increase in incremental flow cross-sectional area coincides with at least the direction of increasing flow velocity, preferably the strainer outlet being defined by a surface of reducing diameter in the direction of fluid flow. The first region of flow defined by the strainer basket wall has an approximately cylindrical shape, and the second region of flow defined by the strainer basket wall with the inner wall surface of the strainer body has an approximately annular outer shape. The strainer outlet has an incremental cross-sectional area in the direction of fluid flow, and a region of the strainer outlet having a relatively higher incremental cross-sectional area is aligned coincident with at least one of: a region about the strainer basket at the junction with the outlet having a flow area relatively less than a coincident flow area of the strainer outlet, and/or a flow region about the strainer basket having a fluid flow velocity higher than a coincident fluid flow velocity of the strainer outlet. In preferred embodiments of this aspect of the invention, the strainer outlet may have a junction region downstream of the inner body wall surface, with the junction region having a reducing profile of a conical reducer. In the area of the intersection of the second region of flow and the outlet, the approximately cylindrically shaped basket wall may also have a conical shape, the second region of flow in the direction of fluid flow having increasing area for fluid flow toward regions of relatively higher volumetric flow.
An objective of the invention is to provide a strainer which is relatively small in size and which has relatively low friction loss, as desirable in fire protection systems. Another objective of the invention is to provide a low cost strainer with low friction losses, i.e. a small pressure drop between the strainer inlet and strainer outlet as water passes through the strainer.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
REFERENCES:
patent: 711535 (1902-10-01), Scholl
patent: 1273656 (1918-07-01), Paget
patent: 1704634 (1929-03-01), Snider
patent: 2465404 (1949-03-01), Sonntag
patent: 2647636 (1953-08-01), Rafferty
patent: 4961847 (1990-10-01), Amr
patent: 5132013 (1992-07-01), Thompson
Approval Standard: Strainers for Use With Water Spray Systems; Class No. 5551; Jun. 26, 1963; reissued Aug. 1, 1970; Factory Mutual Research Corporation; p. 3.
Subject 321, Outline of Investigation for Pipeline Strainers; Issue No. 2; Jun., 1991; Copyright 1989, 1991 Underwriters Laboratories Inc.; p. 6.
Pipe Line Strainer Model A; Grinnell Corporation, Exeter, NH; Printed in U.S.A. 9-82 (Pamphlet).
Pipe Line Strainer Model B-1; Grinnell Corporation, Exeter, NH; Printed in U.S.A. 1-93 (Pamphlet).
Archibald Thomas E.
Ringer Yoram
Drodge Joseph W.
Fish & Richardson P.C.
Grinnell Corporation
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