US3863672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual action pilot
Assignee: BWB Controls Inc
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Filing: 1973-09-06
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Granted: 1975-02-04
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Expires: 1993-09-06
Abstract
Abstract A dual action high-low pressure sensing pilot valve comprising an elongated valve body incorporating a single pressure receiving piston and a pair of independently adjustable compression spring biased valve actuating pistons selectively operable by the single pressure piston.
Inventors
- 👤 Gerold F Theriot
- 👤 Frank M Hoofnagle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:57
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/0401; F15B13/0402; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7723; Y10T137/7725; Y10T137/8593; Y10T137/87169; Y10T137/87217; Y10T137/87225
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
315 words
A pilot valve comprising a valve body, a bore within said body, first and second valve pistons movably disposed within said bore, said pistons being movable both as a unit and independently of each other, a control fluid inlet in communication with said bore, a control fluid outlet in communication with said bore, a control fluid bleed port, a pressure sensing inlet in said body, biasing means biasing said first and second valve pistons to a first position responsive to sensing of pressure below a predetermined minimum pressure where said control fluid inlet is blocked and said control fluid outlet is communicated with said bleed port, pressure means moving said first and second valve pistons as a unit to a second position responsive to the sensing of a predetermined pressure at said pressure sensing inlet, at which second position said control fluid inlet is communicated with said control fluid outlet and said bleed port is blocked, said biasing means comprises first and second compression springs respectively associated with said first and second valve pistons, the second spring being of greater rigidity than the first spring and maintaining said second piston in a fixed position relative to said first piston in said first and second positions, the first spring controlling movement of said first and second pistons as a unit from the first to the second position, said pressure means moving said first and second valve pistons to a third position responsive to sensing an excess of pressure at said pressure sensing inlet thereby causing a blocking of said control fluid inlet, said pressure sensing means comprising a unitary pressure piston positioned inwardly of said pressure sensing inlet and operatively engaged with said valve pistons, and including means for independently adjusting the biasing force of the first spring without affecting the force required to move the second piston from the second piston to the third position.
Claim 2
Dependent Claim
315 words
A pilot valve comprising a valve body, a bore within said body, first and second valve pistons movably disposed within said bore, said pistons being movable both as a unit and independently of each other, a control fluid inlet in communication with said bore, a control fluid outlet in communication with said bore, a control fluid bleed port, a pressure sensing inlet in said body, biasing means biasing said first and second valve pistons to a first position responsive to sensing of pressure below a predetermined minimum pressure where said control fluid inlet is blocked and said control fluid outlet is communicated with said bleed port, pressure means moving said first and second valve pistons as a unit to a second position responsive to the sensing of a predetermined pressure at said pressure sensing inlet, at which second position said control fluid inlet is communicated with said control fluid outlet and said bleed port is blocked, said biasing means comprises first and second compression springs respectively associated with said first and second valve pistons, the second spring being of greater rigidity than the first spring and maintaining said second piston in a fixed position relative to said first piston in said first and second positions, the first spring controlling movement of said first and second pistons as a unit from the first to the second position, said pressure means moving said first and second valve pistons to a third position responsive to sensing an excess of pressure at said pressure sensing inlet thereby causing a blocking of said control fluid inlet, said pressure sensing means comprising a unitary pressure piston positioned inwardly of said pressure sensing inlet and operatively engaged with said valve pistons, and including means for independently adjusting the biasing force of the first spring without affecting the force required to move the second piston from the second piston to the third position.
Claim 3
Dependent Claim
41 words
The pilot valve of claim 1 including means for independently adjusting the biasing force of the second spring without affecting the force required to move the first and second pistons as a unit from the first position to the second position.
Claim 4
Dependent Claim
106 words
The pilot valve of claim 2 wherein said first piston comprises an elongated sleeve engaged at one end by the associated first spring and having a second end aligned with said pressure sensing inlet and said pressure piston, said second piston extending through said first piston and being engaged by the associated second spring at the end thereof corresponding to the spring engaged end of the first piston, abutment means limiting the spring induced movement of the second piston relative to the first piston, the second end of the second piston projecting beyond the second end of the first piston for engagement with the pressure piston.
Claim 5
Dependent Claim
18 words
The pilot valve of claim 3 wherein said pressure piston presents different size alternatively usable pressure receiving faces.
Claim 6
Dependent Claim
106 words
The pilot valve of claim 1 wherein said first piston comprises an elongated sleeve engaged at one end by the associated first spring and having a second end aligned with said pressure sensing inlet and said pressure piston, said second piston extending through said first piston and being engaged by the associated second spring at the end thereof corresponding to the spring engaged end of the first piston, abutment means limiting the spring induced movement of the second piston relative to the first piston, the second end of the second piston projecting beyond the second end of the first piston for engagement with the pressure piston.
Claim 7
Dependent Claim
268 words
A pilot valve comprising a valve body, a bore within said body, first and second valve pistons movably disposed within said bore, a control fluid inlet in communication with said bore, a control fluid outlet in communication with said bore, a control fluid bleed port, a pressure sensing inlet in said body, biasing means biasing said first and second valve pistons to a first position responsive to sensing of pressure below a predetermined minimum pressure where said control fluid inlet is blocked and said control fluid outlet is communicated with said bleed port, pressure means moving said first and second valve pistons as a unit to a second position responsive to the sensing of a predetermined pressure at said pressure sensing inlet where said control fluid inlet is communicated with said control fluid outlet and said bleed port is blocked, said pressure means moving said first and second valve pistons to a third position responsive to sensing of excess pressure at said pressure sensing inlet causing a blocking of said control fluid inlet, said biasing means comprising first and second compression springs respectively associated with said first and second valve pistons, said first spring controlling movement of said first and second pistons as a unit from the first to the second position, said second spring controlling movement of the second piston from the second position to the third position independently of the biasing force of the first spring, and means for independently adjusting the biasing force of the first spring without affecting the force required to move the second piston from the second position to the third position.
Claim 8
Dependent Claim
268 words
A pilot valve comprising a valve body, a bore within said body, first and second valve pistons movably disposed within said bore, a control fluid inlet in communication with said bore, a control fluid outlet in communication with said bore, a control fluid bleed port, a pressure sensing inlet in said body, biasing means biasing said first and second valve pistons to a first position responsive to sensing of pressure below a predetermined minimum pressure where said control fluid inlet is blocked and said control fluid outlet is communicated with said bleed port, pressure means moving said first and second valve pistons as a unit to a second position responsive to the sensing of a predetermined pressure at said pressure sensing inlet where said control fluid inlet is communicated with said control fluid outlet and said bleed port is blocked, said pressure means moving said first and second valve pistons to a third position responsive to sensing of excess pressure at said pressure sensing inlet causing a blocking of said control fluid inlet, said biasing means comprising first and second compression springs respectively associated with said first and second valve pistons, said first spring controlling movement of said first and second pistons as a unit from the first to the second position, said second spring controlling movement of the second piston from the second position to the third position independently of the biasing force of the first spring, and means for independently adjusting the biasing force of the first spring without affecting the force required to move the second piston from the second position to the third position.
Claim 9
Dependent Claim
41 words
The pilot valve of claim 6 including means for independently adjusting the biasing force of the second spring without affecting the force required to move the first and second pistons as a unit from the first position to the second position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |