Many technologies have been used to provide vacuum for chemical and pharmaceutical processes. Some examples include steam jet ejector systems using the Venturi effect to draw a vacuum, liquid-ring vacuum pumps using water as a sealant and rotary vane vacuum pumps using a once-through sealing system. Each of these technologies continues to have a place in chemical and pharmaceutical applications, but dry screw vacuum technology is preferred in most chemical and pharmaceutical applications since no operating fluid is required to compress the process gas.
In a screw vacuum pump, two interlocking screw-shaped rotors rotate in opposite directions. The process vapours are drawn in, trapped between the cylinder and screw chambers, compressed, and transported to the gas outlet.
During the compression process, the screw rotors do not contact each other or the cylinder. Precise manufacturing and minimal clearance between the moving parts enable this and guarantee an ultimate pressure of Advantages of Dry Screw Vacuum Pumps:
- Dry compression, no contamination or reaction possible between process gas and operating fluid
- Ultimate vacuum
- Energy efficient
- Can be designed for nearly all process gases thanks to material selection and temperature regulation
Summary
The choice of vacuum technology is influenced by rising energy costs, environmental regulations and increasing costs of water treatment and hazardous waste disposal. As a result, the market has been pushed to seek vacuum technologies that will provide high efficiency while minimizing waste streams.
Dry screw vacuum pumps can be the right choice in that they can provide high efficiency while reducing additional waste streams through the elimination of operating fluids, whether they be steam, water or oil. As stated above, dry screw pumps are frequently integrated into custom-designed vacuum systems incorporating components to optimize the operation and capability of the vacuum pump concerning flow capacity and vacuum level and to protect the pump and parts.
Reference: pumpsandsystems.com