Fume hood controller
US4528898A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1984 |
| Grant date | Jul 16, 1985 |
| Priority date | — |
| Expiry date | Mar 5, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB08B15/023
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A fume hood controller system in which the sash position is monitored by a transducer which provides a signal indicative of the area of the hood opening. A variable speed controller responsive to the sash position signal to provides a fan speed which varies as a function of the sash opening. An optional circuit monitors the power drawn by the motor and compares the actual power drawn by the motor with the expected power for the present sash position. If the actual power falls below the threshold, an alarm signal is generated indicating a reduced air flow in the fume hood. Additionally, motor overload may be detected by comparing the motor speed control signal with the actual motor speed. An alternate embodiment is shown in which the present invention may be used to control a single blower which exhausts a plurality of fume hoods while maintaining a substantially constant face velocity in each hood.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.