Rotary Vane compressors manage ratios up to 7:1 in compression applications.
Ro-Flo rotary vanes have a MAWP of 200 psig (13.6 barg).
Rotary Vane compressors are not sensitive to high inlet pressures
Rotary Vane compressors are capable of operating in very deep vacuum ranges
Liquid Ring compressors can manage ratios up to 4:1
Multi-stage Liquid Rings can reach discharge pressures up to about 200 psig
Liquid Rings are not tolerant of high inlet pressures
Liquid ring compressors are capable of operating in very deep vacuum ranges
Rotary vanes require a small amount of oil which is continuously injected for lubrication purposes – including the compression chamber
Rotary vane lubricant is usually coalesced and captured downstream of the compressor
Liquid rings do not require lubricant injection into the compression chamber – the vanes do not contact the housing
Oil is required for the compressor bearings and seals. Oil may also be used as the sealing fluid.
Rotary vane compressors can be used with a Variable Frequency Drive to maximize operational efficiency.
Rotary vane efficiency is not affected by gas inlet temp.
A liquid ring compressor has an impeller that churns a rotating ring of liquid (motive liquid) to form the compression chamber seal. This process can consume twice the power of a vane compressor
The efficiency of a liquid ring compressor is affected by the gas inlet temperature
Liquid ring compressors require several stages of filtration of the motive liquid, which requires additional pumps/power
Ro-Flo sliding vane compressors are water jacketed to provide thermal stabilization of the cylinder and remove heat from the bearings.
Process gas is typically cooled by a heat exchanger downstream of the compressor
A large portion of the heat is absorbed by the sealing fluid. This fluid will need to be cooled and will need to be removed from the process stream.
Rotary Vane compressors can tolerate almost any gas, as well as varying compositions with standard metalurgy
Liquid ring compressors are sensitive to the gas composition being compressed
Liquid ring compressors require special alloys to prevent corrosion and/or erosion.
Gas composition must be managed to prevent cavitation damage to the rotor.
Sliding vane capacity control is most commonly implemented via a variable speed drive (VSD) or gas recycle loop.
Typically the only way to control capacity of a liquid ring is gas recycle loop or suction throttling.
Hand tools are needed for basic maintenance. A complete repair can be completed by properly trained machine shops.
Requires maintenance at a qualified repair facility, typically the OEM.