Browse Prior Art Database

Vacuum Detector With Hysteresis

IP.com Disclosure Number: IPCOM000084032D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Beistle, RG: AUTHOR

Abstract

The mechanism as depicted schematically shows a tube flowmeter which provides a reliable and low-cost vacuum detector.

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Vacuum Detector With Hysteresis

The mechanism as depicted schematically shows a tube flowmeter which provides a reliable and low-cost vacuum detector.

Flowmeter 10 comprises housing 1 with stepped designed cavities 12. Sphere 2 is loosely contained within the stepped cavity. Stop or travel limit means 3 controls the travel of sphere 2 within the cavity 12. A light source 4 is positioned for incidenting light rays within the cavity. Light detector 5 is positioned opposite to light source 4 for collecting the rays and outputting a signal whenever the ray path is not blocked by sphere 2. Seal 6 provides sealing for the cavity 12.

In operation, with no vacuum applied at port 14, sphere 2 will be at rest against lever stop 3. As the vacuum pressure is increased at port 14, fluid flow will increase in the direction shown by arrow 16 until sphere 2 is raised in the larger diameter of cavity 12. As there is no taper to cavity 12, the sphere 2 will continue to rise until it reaches step 18 in cavity 12. When the smaller diameter 18 is reached, the force lifting sphere 2 will increase, lifting sphere 2 to the upper stop 3. Less flow (therefore less vacuum) is required to support sphere 2 at this point than is required to lift sphere 2 away from the lower stop 3.

The hysteresis is determined by the ratio of the two diameters in cavity 12. The operating point is determined by the mass and diameter of sphere 2, and the ratio of sphere 2 diameter to the larger diameter of cavi...