US4249556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Isolating and backflow preventing valve assembly
Assignee: Ecolab Engineering GmbH
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Filing: 1978-10-25
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Granted: 1981-02-10
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Expires: 1998-10-25
Abstract
Abstract A liquid supply system in which liquid is only supposed to flow from a high-pressure upstream portion to a low-pressure downstream portion is provided with a backflow preventer and upstream thereof with an isolating valve assembly. The backflow preventer opens completely whenever the pressure upstream of itself drops below a predetermined minimum, thereby draining the conduit downstream of itself to prevent reverse flow in the line. The isolating valve assembly continuously monitors the pressure in the upstream and downstream conduit portions and shuts a cutoff valve between these portions whenever the pressure differential between the two portions falls below a predetermined minimum, while simultaneously depressurizing or draining the downstream portion. The operation of the isolating valve assembly therefore ensures that in case of a sudden pressure surge downstream of the backflow preventer the cutoff valve will close until the downstream portion has been depressurized sufficiently to actuate the backflow preventer. The isloating valve assembly has a pair of pistons that operate the cutoff valve either directly or through a solenoid, and which are isolated from each other in separate cylinders to eliminate mixing of the liquids in the upstream and downstream conduit portions. A pilot valve may be connected to the cylinder of one of these pistons for applying to this one cylinder the relatively high pressure in the upstream conduit portion when the valve is supposed to operate, and the other cylinder is normally continuously pressurized with this upstream pressure.
Inventors
- 👤 Alfred Waletzko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:15
CPC Classifications
E; E03; E03C; E03C1/00; E03C1/02; E03C1/10; E03C1/104; E03C1/108; F; F16; F16K; F16K17/00; F16K17/20; F16K17/22; F16K17/32; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544; Y10T137/2557; Y10T137/2559; Y10T137/2574; Y10T137/2579; Y10T137/2589; Y10T137/3149; Y10T137/3185; Y10T137/3294; Y10T137/3331; Y10T137/7722; Y10T137/7758; Y10T137/7761; Y10T137/7762; Y10T137/7781; Y10T137/7783
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
266 words
An isolating valve assembly for use in combination with a conduit through which liquid is only supposed to flow from a high-pressure upstream portion to a low-pressure downstream portion, said assembly comprising: a cutoff valve between said portions and having a cutoff-valve member displaceable between a closed position blocking fluid flow between said portions and an open position permitting fluid flow between said portions; a drain valve having a drain conduit connected to said downstream portion, a vent line opening outside said portions generally at atmospheric pressure, and a drain-valve member displaceable between a closed position isolating said drain conduit from said vent line and an open position connecting said drain conduit to said vent line; an operator having an upstream compartment, a downstream compartment, and an operating member exposed in opposite directions in and partially defining said compartments, said operating member being operatively connected to both of said valve members and being jointly displaceable therewith between one end position corresponding to said open position of said cutoff-valve member and said closed position of said drain-valve member and another end position corresponding to said closed position of said cutoff-valve member and said open position of said drain-valve member; and conduit means connecting said upstream and downstream portions to said upstream and downstream compartments for pressurizing same and holding said operating member in said one end position when the pressure in said upstream portion exceeds that in said downstream portion by a predetermined minimum and for displacing said operating member into said other end position when the pressure differential between said portions falls below said predetermined minimum.
Claim 2
Dependent Claim
266 words
An isolating valve assembly for use in combination with a conduit through which liquid is only supposed to flow from a high-pressure upstream portion to a low-pressure downstream portion, said assembly comprising: a cutoff valve between said portions and having a cutoff-valve member displaceable between a closed position blocking fluid flow between said portions and an open position permitting fluid flow between said portions; a drain valve having a drain conduit connected to said downstream portion, a vent line opening outside said portions generally at atmospheric pressure, and a drain-valve member displaceable between a closed position isolating said drain conduit from said vent line and an open position connecting said drain conduit to said vent line; an operator having an upstream compartment, a downstream compartment, and an operating member exposed in opposite directions in and partially defining said compartments, said operating member being operatively connected to both of said valve members and being jointly displaceable therewith between one end position corresponding to said open position of said cutoff-valve member and said closed position of said drain-valve member and another end position corresponding to said closed position of said cutoff-valve member and said open position of said drain-valve member; and conduit means connecting said upstream and downstream portions to said upstream and downstream compartments for pressurizing same and holding said operating member in said one end position when the pressure in said upstream portion exceeds that in said downstream portion by a predetermined minimum and for displacing said operating member into said other end position when the pressure differential between said portions falls below said predetermined minimum.
Claim 3
Dependent Claim
64 words
The valve assembly defined in claim 1, further comprising means connected in said conduit downstream of said closable valve and including a backflow preventer for venting said conduit downstream of said closable valve when the pressure upstream of said backflow preventer falls below a predetermined minimum pressure, said drain conduit being connected to said downstream portion between said closable valve and said backflow preventer.
Claim 4
Dependent Claim
22 words
The valve assembly defined in claim 1 wherein said means includes a conduit connected between said downstream compartment and said downstream portion.
Claim 5
Dependent Claim
47 words
The valve assembly defined in claim 1, wherein said conduit means includes a pilot valve connected to said downstream compartment and between said upstream and downstream portions for applying to said downstream compartment the pressure in said upstream portion when said pressure differential falls below said minimum.
Claim 6
Dependent Claim
44 words
The valve assembly defined in claim 4 wherein said pilot valve is a spool valve having a valve member having one end exposed to the pressure in said upstream conduit portion and an opposite end exposed to the pressure in said downstream conduit portion.
Claim 7
Dependent Claim
25 words
The valve assembly defined in claim 5 wherein said one end of said valve member is of smaller effective surface area than said opposite end.
Claim 8
Dependent Claim
53 words
The valve assembly defined in claim 5 wherein said ends of said valve member are of generally the same effective surface area, said spool valve including a spring bearing against said valve member in a direction opposite the direction in which said pressure of said upstream portion is effective on said valve member.
Claim 9
Dependent Claim
54 words
The valve assembly defined in claim 5 wherein said valve body is displaceable between one end position connecting said downstream compartment to said upstream portion, an other end position venting said other compartment to the atmosphere, and through an intermediate position connecting said other compartment neither to said upstream portion nor to the atmosphere.
Claim 10
Dependent Claim
47 words
The valve assembly defined in claim 5 wherein said pilot valve has a housing formed with outwardly open throughgoing holes exposing said valve member intermediate its said ends to the atmosphere, whereby fluid effective on said one end and fluid effective on said opposite end cannot mingle.
Claim 11
Dependent Claim
61 words
The assembly defined in claim 1 wherein said operating member includes an upstream piston and a downstream piston and a stem axially extending between said pistons and establishing therebetween a predetermined minimum axial spacing, said operator having upstream and downstream cylinders respectively housing said pistons and forming the respective compartments, said compartments being on opposite axial faces of the respective pistons.
Claim 12
Dependent Claim
21 words
The valve assembly defined in claim 10 wherein said drain means includes a spool valve in part formed by said stem.
Claim 13
Dependent Claim
64 words
The valve assembly defined in claim 10 wherein said cutoff valve is a membrane valve connected between said portions and having a membrane pressurizable to open said cutoff valve, said operating means including a pilot valve connected to and operated by said pistons and connected between said upstream portion and said membrane for pressurizing same when said pressure differential is greater than said minimum.
Claim 14
Dependent Claim
81 words
The valve assembly defined in claim 12, further comprising reversing means including a first valve connected between said pilot valve and said membrane and a second valve connected to said downstream portion for respectively disconnecting said pilot valve from said membrane and draining said downstream portion when electricity is applied to said first and second valves and for connecting said pilot valve to said membrane and closing said second valve when no electricity is applied to said first and second valves.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |