PSI-Polymer Systems Inc. Introduces Low Viscosity Seal For Bolt Type Screen Changers Conover, NC (October 16, 2013)
PSI-Polymer Systems has recently introduced a new seal, applicable to any of its bolt type screen changers and divert valves, which prevents material leakage on extremely low viscosity polymers and fluids.
With bolt-type screen changers and divert valves, there is a correlation between the viscosity of the polymer and the ability of the screen changer to maintain a reliable, leak free seal. This is because the precisely machined clearance between the housing and bolts relies on the viscosity of the polymer to create a balance between providing minimal lubrication between the housing and bolts while also inhibiting flow across the bolt L/D to the atmosphere. Until now, low and very low-viscosity melts have been problematic for bolt-type screen changers because of the limitations on the clearances that must be maintained.
Common with hot melt adhesives and low viscosity polymers, these leaks are a serious problem, as they not only create a mess and require shutting down the machine for repair and cleaning, but they also can become a serious fire and safety hazard.
As a solution to this common problem, PSI has invented a seal technology that will work effectively for polymers with extremely low viscosities. So far, the new seal has been successfully tested on viscosities as low as 1 cP (toluene, etc) to 300,000 cP and has proven capable of sealing nitrogen at over 2,000 psi. The design is equally effective at higher viscosities that can be handled by existing seal types. It can be used in any PSI piston type screen changer unit or divert valve, and is ideal for processing high melt materials, adhesives, solvents, etc.
“This seal is a perfect solution for the leaks that many of our customers experience when using low viscosity polymers,” said Glenn Woodcock, President of PSI-Polymer Systems. “It’s always been our goal to continue to be leaders and innovators in our industry. We know that our customers’ success is tied to our own success, and this new seal will help all of our customers improve their products’ efficiency and quality.”
The new seal is currently holding a provisional patent, awaiting pending status.