Time delayed shut-down circuit for recirculation pump
US3963375A · kind A · utility
72Cited by
6References
1Claims
0Family size
Inventor
Key dates
| Filing date | Mar 12, 1974 |
| Grant date | Jun 15, 1976 |
| Priority date | — |
| Expiry date | Mar 12, 1994 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04B49/06
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A circuit is provided for shutting off the motor of an intermittently activated, electrically powered fluid recirculation pump to prevent the pump motor from burning out its windings or bearings. A power control relay is energized to activate the pump motor for a predetermined period of time, allowing the pump to reach steady state flow condition, after which a time delay relay opens and current flows to the power control relay through a pressure switch. The pressure switch opens to shut-off the recirculation pump motor whenever the pump discharge pressure falls below a predetermined minimum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.