Recirculation from pump discharge through a cyclone separator, delivering clean fluid to the seal chamber and solids to pump suction.
API Seal Plan 31 is like Plan 11 with a bypass from pump discharge via cyclone separator.
- Similar to Plan 11, with the addition of a cyclone separator.
- Cyclone separator needs at least a 25 psi [1.7 bar] differential between pump discharge and the seal chamber for optimum performance.
- For use with services containing solids with a specific gravity at least twice that of the process fluid.
- The difference in pressure between the two separator outlets should be as close to zero as possible.
- Maximum particle size in the process should be less than one quarter the size of the inlet orifice.
- If the process stream is very dirty or is a slurry, Plan 31 is not recommended.
- Solid particles are centrifuged from the stream and routed back to pump suction.
- Cyclone separator must be monitored for abrasive wear which reduces performance.
- Easy elimination of solid particles
- Cyclone separator facilitates clean flush
- Constant maintenance checks for cyclone separators required