Backflow preventer

Details Backflow preventer Backflow preventer

2006-10-31

2006-10-31

Rivell, John (Department: 3753)

Fluid handling

Line condition change responsive valves

Direct response valves

C137S541000, C137S542000, C251S297000

Reexamination Certificate

active

07128088

ABSTRACT:
A backflow assembly including a housing with a passage having at least one check valve positioned therein to permit fluid flow in one direction while preventing fluid flow in the reverse direction. The check valve includes a valve head connected to a stem having an outer surface. A hump extends radially outward from the outer surface of the stem. The stem is guided by a bushing during opening and closing of the valve. The bushing includes at least one retention member that moves along the outer surface of the stem during opening and closing of the valve. The interaction between the retention member and the hump on the outer surface of the stem causes a higher friction loss during opening and closing of the valve than other portions of the outer surface.

REFERENCES:
patent: 144844 (1873-11-01), Gould et al.
patent: 2267902 (1941-12-01), Eddins
patent: 2701579 (1955-02-01), Hasselquist
patent: 2711186 (1955-06-01), Argibay
patent: 4232704 (1980-11-01), Becker et al.
patent: 4284097 (1981-08-01), Becker et al.
patent: 5085076 (1992-02-01), Engelmann
patent: 5113899 (1992-05-01), Yonezawa
patent: 5584315 (1996-12-01), Powell
patent: 5711341 (1998-01-01), Funderburk et al.
patent: 6502598 (2003-01-01), Engelmann
“The AMES Challenge”, Ames Fire & Waterworks, Sacramento, CA, 4 pages.

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