Method and apparatus for controlling flow of work materials
US4403764A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 8, 1981 |
| Grant date | Sep 13, 1983 |
| Priority date | — |
| Expiry date | Oct 8, 2001 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16K7/06
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An improved method for precision control of a wide variety of work material liquids and an improved pinch valve incorporating that method is disclosed. The method involves constricting a discrete site on a resilient tube having liquids flowing therethrough to pinch off flow, then moving the constriction upstream to maintain flow stoppage and create a partial vacuum to cause positive suck back, the distance the constriction is moved being selectively determinable to selectively adjust suck back. An apparatus for practicing the method comprises an external roller shutoff member which is movable in a direction to intersect with and then move counter to work material flow within a resilient tube to compress the tube against a ramp and gives positive repeatable shutoff of the flow. The further upstream movement of the roller shutoff member after reaching the shutoff position allows the natural resilience of the tube to return from its compressed to its natural uncompressed position and thereby create a partial internal vacuum which in turn creates a positive suck back of work material at the outlet to provide dripless precise shutoff. The flow through the tube is unobstructed when the v…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.