what is the maximum particle size that can be pumped with a pump with mechanical seal?

Question

it is a pp centrifugal chemical process pump

Answer 1

The mechanical seal on a centrifugal pump has nothing to do with maximum particle size. That is a characteristic of the impeller design. Some open impeller designs are intended to pump heavy or large particles and even debris. Some closed impeller designs will show this size limitation in the pump specification.
Inquire from the pump manufacturer's representative.

Answer 2

It all really depends on the service of the process fluids and plant standards. Usually when the pump is needing a seal pot containment is an issue. Pressurizing the seal pot with the nitrogen forces the barrier fluid to be pushed into the primary seal and into the process fluid. If in the event the primary seal sees a catastrophic failure the pressurization of the secondary seal limits the emmisions to the atmosphere. API plans 53's and 54's are also used when the process fluid is very dirty or at elevated temperatures. Hope this helps. --C.

Answer 3

The appropriate answer is very much dependent on the type of solid material being pumped, size of the particle, liquid properties such as viscosity, and perhaps even concentration of the particles.

One critical factor is settling rate - you must insure velocity is high enough to prevent particles from settling anywhere in the sytem, even if they are pumped successfully.

If the particle is an emulsion particle (liquid suspended in another liquid), care must be taken to prevent excess shear which can destabilize the emulsion. Usually emulsion particle size is 1 micron or less.

If the particle is a solid, it's properties must also be considered - is it frangible or breakable if shear is too high?

Some pumps such as Moyno are designed to pump cherries with pits intact. I would consider pits "large" particles. Of course, pump factors such as physical size, suction head, discharge head, etc. are also important.

It seems like a simple question, but handling particles can be difficult if all factors are not carefully considered and addressed.

Answer 4

I suggest you do a web search for John Crane seals or Borg Warner seals because the answer to your question may vary depending on exactly what kind of seal you want. There are simple mechanical seals and seals designed specifically to handle fluids up to and including slurries.

Partical size, type and quanitity all can have a impact of the mechanical seal. Real "sticky" particles can be a special problem.