Rotary Lobe Pumps vs. Sliding Vane Pumps
General Principle of Operation:
The above pumps are both rotary positive displacement pumps. This results in their capability to pump any given flow rate desired within their range at any given pressure desired within their range.
Sliding Vane Pumps have vanes that slide in and out as the shaft turns and rotates the vanes within an elliptical casing.
LobePro Rotary Lobe Pumps have 2 shafts kept in timing by gears. Fluid is trapped in the lobe cavities on the suction side of both shafts and then forced around the outside case until discharged on the other side. The lobes do not touch each other. Typical operating speed in clean liquid is from 500 to 650 rpm.
Advantages of LobePro Rotary Lobe Pumps:
- The fluid being pumped by sliding vane pumps must be very clean otherwise contaminates may cause the vanes to stop sliding and the pump to fail. Rotary lobe pumps can handle hard contaminates below 3 mm in size and compressible contaminates that are considerably larger.
- Sliding Vane Pump Manufacturers recommend a strainer 4 times the area of the intake pipe be installed which must be cleaned regularly to avoid pump starvation. A filter and subsequent frequent cleaning labor is not necessary with a LobePro rotary lobe Pump reducing the installation and maintenance costs, and improving the NPSH available. If filtration is required by other system components like flow meters, it can be reduced size, installed on discharge side.
- Sliding vane pumps either cannot operate in reverse or can only be operated for 10 minutes in reverse with reduced output. LobePro pumps will operate in either direction indefinitely at full speed. This allows the same pump to be used for both loading and unloading saving trouble, time and cost.
- Sliding vane pumps mention states that they are self priming but do not specify the maximum suction lift. Rotary Lobe pumps will self prime with water up to 25 ft.
- LobePro pumps have oil lubricated cartridge seals. As a result, LobePro pumps can be run dry for a period of time.
Disadvantage of Rotary Lobe Pumps:
The initial investment may be greater for a rotary lobe pump because it is more costly to build. This is usually made up for by less downtime and maintenance.