Vacuum drying system with cryopumping of solvent recovery feature
US5263268A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1992 |
| Grant date | Nov 23, 1993 |
| Priority date | — |
| Expiry date | Jan 13, 2012 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF26B25/006
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
In the drying of solvents-containing material in a vacuum concentrator and which involves condensation of evolved solvents in a cold trap, simplified and inexpensive flow blocking devices are provided intervening an outlet of the cold trap and an inlet to the vacuum pump with which the concentrator is evacuated. The flow blocking practiced allows cryopumping effect to ensue between the concentrator and cold trap such being the agency by which solvent vapor outflows from the concentrator and is recovered by condensation thereof in the cold trap. Near complete solvent recovery can be achieved and carryover of solvent to the vacuum pump is reduced to insignificant measure. In one form, flow blocking is attained by use of a simple pressure differential valve. This valve will stay closed as long as absolute pressure differential acting on the valve is a desired value, such as one corresponding to difference of condition of vacuum at pump inlet and at the upstream end of the valve, such differential being one at which cryopumping conditions exist. If the differential is greater, the valve will open to reconnect system flow to the vacuum pump which continues until cryopumping condition is…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.