Intermittent pilot type burner control with a single control relay
US5020988A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 22, 1990 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Oct 22, 2010 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23N2235/18
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A burner control system for an intermittent pilot burner system uses a single pole double throw relay to control first and second electromagnetic valves respectively supplying fuel for both burners and for the main burner only. The normally open contact pair supplies the current for the first and the normally closed contact pair supplies the current for the second valve. By selecting the valve supplying fuel for both burners to be of the type which has an appreciably higher pull-in current than drop-out current, and by shunting the relay's normally open contacts with a properly selected resistor, only a single relay is necessary. This resistor is selected to supply current sufficient to hold the valve open (current greater than the drop-out value) after the valve has received pull-in current through the closing of these normally open contacts, but insufficient to open the valve. Use of a single relay reduces cost, size, and power, and increases safety of the control system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.