There are many options for choosing the right vacuum system retrofits for you. Many types of vacuum pumps are available, each with different displacement capacities and ultimate vacuum levels. There are four types of freeze-drying commonly used in laboratories: evaporation, concentration, and freeze-drying.
Rotary Vane
Traditional Rotary Vane (RV) vacuum pumps are often preferred because they are less expensive than other vacuum pumps, have smaller parts, and can be used in multiple applications; traditional asme vessels are often preferred. To ensure a tight seal, oil is used to lubricate all moving parts and remove heat from the rotors.
Solvents that aren’t captured or recovered from the RV vacuum pump before entering it can condense in oil and cause damage to the inside of the pump. When using an RV pump, collecting any evaporated vapors downstream of the pump is necessary. These vapors can be collected and protected by Cold Traps or condensers.
Diaphragm
Diaphragm vacuum system installations are dry pumps. They use a pulsing motion to open and close valves to move air. This eliminates the need to use oil. The valves are often made of polytetrafluoroethylene, making the pump resistant to corrosives and less susceptible to damage from vapors.
They can be more expensive upfront, but they don’t require any oil. This means that their maintenance and operation costs are much lower than those of oil pumps. Although they can handle viscous liquids and can be used with many samples, the applications for daily pumps are limited to those that require higher vacuum levels.
Hybrid Combination
High vacuum Pumps, also called Combination Vacuum Pumps, have both a Rotary Vacuum Pump and a Diaphragm Pump in one vacuum pump. The diaphragm pumps keep the oil under negative pressure in combination pumps to reduce or eliminate vapors from the RV pump and condense into the oil. This design allows oil to last 10 times longer than RV pumps.
Scroll
Scroll vacuum pumps are dry pumps that use two spiral scrolls to compress air and vapors and then move them towards the exhaust. They can be more expensive up front, but they are very economical to operate over the pump’s life.
