Fail-safe valve relay driver circuit for gas burners
US5085574A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 12, 1989 |
| Grant date | Feb 4, 1992 |
| Priority date | — |
| Expiry date | Oct 12, 2009 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23N2235/14
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A fail-safe gas valve driver circuit controlling the gas supply line of a gas burner, which circuit in its essential circuit elements (FIG. 1) includes an appropriate switching means (S1) effectively feeding a pulsed DC wave form into the rest of the valve relay driver circuit, operatively consisting only of a capacitor (C1) in series with a gas valve relay (K1), which in turn is in parallel with a diode (D1). In operation, the valve relay coil is energized by charging the capacitor with the switch connected to a positive DC voltage source (V.sub.dc ; FIG. 1A), and then grounding the positive end of the capacitor (switch connected to ground) applying a negative voltage across the coil of the relay (FIG. 1B). When the capacitor is again connected to the positive DC voltage source by the switch, the current in the relay coil is sustained by the diode (FIG. 1C). The switch is operated at a sufficiently high rate so the current in the relay coil has insufficient time to decay significantly during the charging cycle of the capacitor before being replenished during the capacitor discharge cycle. With this circuitry the gas supply valve (G.V.) will always go to, or be maintained in, a clo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.