US3720858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Relay timing system
Assignee: Columbia Gas System Service Corp
•
Filing: 1971-07-20
•
Granted: 1973-03-13
•
Expires: 1991-07-20
Abstract
Abstract A timing system having a pair of conductors connected to an alternating voltage source through a switch. The system includes a first charging circuit across the pair of conductors consisting of a first condenser, a diode and an impedance whereby the condenser charges at a given rate. A second charging circuit across the pair of conductors, consisting of a rectifier, a trigger tube and a second condenser and current limiting resistance, acts as a timing circuit. The second condenser receives incremental charges and after a predetermined delay charges above a predetermined minimum value. A third charging circuit is connected across the trigger tube and second condenser and includes a resistance and a third condenser, with a second trigger tube and a resistance across the third condenser. When the second condenser reaches the above predetermined minimum value, the voltage on the third condenser fires the second trigger tube and generates a voltage pulse across its resistance which is supplied to the igniting electrode of a silicon control rectifier which conducts to discharge the first condenser through the operating coil of a relay. The discharge current from the first condenser rises above the pull-in value for the relay and remains above the hold-in value for the relay for a predetermined time after which it drops below such hold-in value. The relay is shown controlling the solenoid valve for a gas burner system. The gas burner system is provided with flame igniter and flame monitoring means. The flame monitoring means is provided with switches which cause the relay to remain closed in the presence of the flame, to remain in an open state upon failure of the flame to ignite and to recycle the system once upon a subsequent flame failure. The entire system can be recycled by opening the switch to the voltage source and then reclosing it.
Inventors
- 👤 G Mercier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:51
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/20; F23N5/203; F23N5/02; F23N5/10; F23N5/102; F23N2223/00; F23N2223/22; F23N2223/26; F23N2223/28; F23N2225/00; F23N2225/08; F23N2227/00; F23N2227/28; F23N2227/38; F23N2229/00; F23N2231/00; F23N2231/06; F23N2231/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
203 words
A timing system comprising: a. a pair of conductors; b. first switch means for connecting said conductors to a voltage source; c. a first condenser; d. a charging circuit for said condenser connected to said conductors, said charging circuit having a time constant of a value to cause the charge on said condenser to rise above a predetermined minimum value after a first time delay following the operation of said first switch means; e. a discharge circuit having a predetermined discharge impedance and comprising said condenser, the operating member of a relay, and a second switch adapted to close in response to a voltage impulse; f. timing means responsive to the operation of said first switch means for generating such voltage impulse after a second time delay in excess of said first time delay; g. said discharge impedance being sufficiently low to cause the discharge current from said condenser, so charged above said minimum value, to rise above the pull-in value of said relay, and the time constant of said discharge circuit being sufficiently high to cause said discharge current to remain above the hold-in value for a third time delay and to drop below said hold-in value after said third time delay.
Claim 2
Dependent Claim
203 words
A timing system comprising: a. a pair of conductors; b. first switch means for connecting said conductors to a voltage source; c. a first condenser; d. a charging circuit for said condenser connected to said conductors, said charging circuit having a time constant of a value to cause the charge on said condenser to rise above a predetermined minimum value after a first time delay following the operation of said first switch means; e. a discharge circuit having a predetermined discharge impedance and comprising said condenser, the operating member of a relay, and a second switch adapted to close in response to a voltage impulse; f. timing means responsive to the operation of said first switch means for generating such voltage impulse after a second time delay in excess of said first time delay; g. said discharge impedance being sufficiently low to cause the discharge current from said condenser, so charged above said minimum value, to rise above the pull-in value of said relay, and the time constant of said discharge circuit being sufficiently high to cause said discharge current to remain above the hold-in value for a third time delay and to drop below said hold-in value after said third time delay.
Claim 3
Dependent Claim
203 words
A timing system comprising: a. a pair of conductors; b. first switch means for connecting said conductors to a voltage source; c. a first condenser; d. a charging circuit for said condenser connected to said conductors, said charging circuit having a time constant of a value to cause the charge on said condenser to rise above a predetermined minimum value after a first time delay following the operation of said first switch means; e. a discharge circuit having a predetermined discharge impedance and comprising said condenser, the operating member of a relay, and a second switch adapted to close in response to a voltage impulse; f. timing means responsive to the operation of said first switch means for generating such voltage impulse after a second time delay in excess of said first time delay; g. said discharge impedance being sufficiently low to cause the discharge current from said condenser, so charged above said minimum value, to rise above the pull-in value of said relay, and the time constant of said discharge circuit being sufficiently high to cause said discharge current to remain above the hold-in value for a third time delay and to drop below said hold-in value after said third time delay.
Claim 4
Dependent Claim
203 words
A timing system comprising: a. a pair of conductors; b. first switch means for connecting said conductors to a voltage source; c. a first condenser; d. a charging circuit for said condenser connected to said conductors, said charging circuit having a time constant of a value to cause the charge on said condenser to rise above a predetermined minimum value after a first time delay following the operation of said first switch means; e. a discharge circuit having a predetermined discharge impedance and comprising said condenser, the operating member of a relay, and a second switch adapted to close in response to a voltage impulse; f. timing means responsive to the operation of said first switch means for generating such voltage impulse after a second time delay in excess of said first time delay; g. said discharge impedance being sufficiently low to cause the discharge current from said condenser, so charged above said minimum value, to rise above the pull-in value of said relay, and the time constant of said discharge circuit being sufficiently high to cause said discharge current to remain above the hold-in value for a third time delay and to drop below said hold-in value after said third time delay.
Claim 5
Dependent Claim
104 words
A system as in claim 1 in which said voltage source is an alternating voltage source and in which said timing means comprises: a. a second condenser; b. charging means for delivering a pulse of charging current to said second condenser during each alternate half cycle of said alternating voltage and for limiting the value of said pulse to a limited value which will produce an incremental rise in the charge on said second condenser; and c. pulse producing means, responsive to said second condenser being charged to a predetermined value substantially in excess of any such incremental rise, for generating said voltage impulse.
Claim 6
Dependent Claim
69 words
A system as in claim 2 in which charging means comprises: a. a series circuit connected between said conductors and including a half-wave rectifier, an impedance, a trigger device adopted to conduct current when the voltage across it rises above a predetermined value, and said second condenser; b. said last named impedance being sufficiently high to limit the value of said pulse of charging current to said limited value.
Claim 7
Dependent Claim
79 words
A system as in claim 3 in which said pulse producing means comprises: a. a circuit connected across said second condenser and comprising said trigger device, and impedance and a third condenser; and b. a circuit connected across said third condenser comprising a second trigger device adapted to conduct current when the voltage across it rises above a predetermined value, and an impedance; c. said voltage impulse being generated across said impedance upon conduction of said second trigger device.
Claim 8
Dependent Claim
59 words
A system as in claim 2 also comprising: discharge dissipating means connected across said second condenser and operable, upon actuation of said first switch for disconnecting said conductors from said voltage source, to dissipate the charge on said second condenser substantially to zero; whereby upon reclosure of said first switch the initial timing operation of said system is resumed.
Claim 9
Dependent Claim
135 words
A system as in claim 1 also comprising: a. a device adopted to be set in operation by the actuation of said relay; b. disconnect means also responsive to the actuation of said relay for opening said charging circuit to said first condenser; c. means responsive to the operation of said device for closing an alternative charging circuit to said first condenser and for opening said alternative charging circuit upon failure of said device to operate; d. the impedance of said alternative charging circuit being of a value to hold the charge on said first condenser at a value to maintain its discharge current through said relay above said hold-in value; e. whereby, upon such failure, the discharge current from said first condenser will decay below said hold-in value and said relay will become deactivated.
Claim 10
Dependent Claim
124 words
A system as in claim 1 in which said timing circuit includes: a. a second condenser adopted to be charged from said conductors at the end of said second time delay, to a predetermined voltage; b. means responsive to said predetermined voltage to generate a periodic series of said voltage impulses, the time between successive of said voltage impulses being less than that required for said first condenser to acquire a charge sufficient to deliver a discharge current through said second circuit having a value above said pull-in value; c. whereby after said discharge current has dropped below said hold-in value, subsequent discharges of said first condenser through said operating member of said relay will be insufficient to cause said relay to be actuated.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |