Apparatus for visually indicating when a pool filter is dirty
US3939796A · kind A · utility
3Cited by
5References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1974 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Sep 27, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/8326
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Apparatus for indicating when a swimming pool filter needs to be cleaned, which comprises a flexible diaphragm covering an opening in the conduit on the inlet side of a pool filter and a housing covering the diaphragm with a movable piston member inside the housing and engaging the surface of the diaphragm. Spring means urges the piston against the diaphragm to counteract pressure of water in the conduit against the diaphragm. A movable flag is operated by the piston means to indicate through a window in the housing when the piston has moved a predetermined distance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.