Fume hood sash sensing apparatus
US5117746A · kind A · utility
Inventor
Key dates
| Filing date | Jul 2, 1990 |
| Grant date | Jun 2, 1992 |
| Priority date | — |
| Expiry date | Jul 2, 2010 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF24C15/2021
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An apparatus for sensing the extent to which the sash or sashes covering the access opening of a fume hood are open. The apparatus includes a source of electromagnetic energy at a selected AC frequency below 10.sup.6 MHz, with a preferred frequency range being from 10 KHz to 100 KHz. The source preferably includes a wire coil connected to an oscillator of the selected frequency with the detector for the AC signal also preferably including a wire coil. Suitable elements are also provided for controlling the amount of electromagnetic energy from the source wire coil which reaches the detector wire coil as a function of sash opening. For the various embodiments, the apparatus may be arranged (a) with either one or both of the coils mounted in a fixed bar, control elements being mounted to the sashes; (b) with both coils mounted to sashes; or (c) with a single coil, either fixedly mounted or mounted to a sash, being used as both the source and detector coil, control elements being selectively mounted to the sashes. Embodiments which are variations on the three basic types discussed above are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.