Air pressure gauge
US4166397A · kind A · utility
Inventor
Key dates
| Filing date | Apr 27, 1978 |
| Grant date | Sep 4, 1979 |
| Priority date | — |
| Expiry date | Apr 27, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L7/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An air pressure gauge comprises a tube of rigid transparent material closed at one end and open at the other for connection to a source of pressure to be measured. The tube has graduated notches along its length and is constituted by at least two cylindrical portions connected together. One portion is adjacent the open end and the other smaller portion extends toward the closed end of the tube. A resilient piston slides in the tube and comprises a plurality of separate coaxial elements of which the outer forms a seal against the inner walls of the tube portion of greater diameter and the inner forms a seal against the inner walls of the portion of smaller diameter. The friction opposing the relative sliding between the two elements is greater than that opposing the sliding of the outer element against the inner walls of the tube portion of greater diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.