Seal Selection for CFG Pump on Slurry Duty

[plantprowler]

We have an application where a somewhat dilute slurry needs to be pumped. What are the best options for a seal for this duty?

The slurry is a saturated salt brine (Na2SO4) with max. 5% solids (w/w) at 95 C. The flowrate is approx. 100 m3/hr at the differential head of 1.5 barg. The solids are hard and crystalline.

The stream is innocuous, inexpensive and non-toxic so some leaks can be tolerated and not absolute isolation is needed. But air leaks must be avoided since the pump suction comes from an evaporator under vacuum (120 mmHg abs) and air leaks cause foaming. A tall leg of approx. 6 m height provides the NPSH for the pump.

Any other tips for specifying / selecting the seal? What are general experiences with pump seals on slurry duty?

 

[micalbrch]

My recommendation would be a stuffing box packing with sealing water ring and connection to avoid air entrance.

 

[TenPenny]

Your application is relatively common. You'll probably want a seal with hard faces and a quench so that the salt crystals can be dissolved. Also think about what happens on shut down, the salt may tend to crystallize on the seal faces.

I recommend you talk to one of the 'good' seal vendors. This application is nothing that unusual, but can cause grief if not done correctly.

Seals on slurry duties are quite common.

 

[niteshgargeck]

I would suggest to use stuffing box packing with lantran ring with grease holes or a water ring. Mech seal will be very expensive because you will have to select an outside flushing fluid in sealing plan.

 

[gempump]

The shaft seal could use the packing seal(most widely used), expeller seal and mechanical seal.I think this pump is small,you may use mech seal which is not very expensive.

Heavy-Duty Centrifugal Slurry Pump Manufacturer

http://www.gempump.com