Local mechanical seals, pumps and complementary pump products supplier Mechanical Rotating Solutions (MRS) commends the Belzona 1321 two-part ceramic-filled epoxy coating for its ability to provide erosion- and corrosion-resistance in metal surfaces.

Recently, MRS was called to repair a badly damaged swing check valve and used Belzona 1321 to refurbish the valve and address cavitation that occurred around the valve seat.

“This particular valve is mounted with a disc that swings on a hinge or shaft. The disc swings off the seat to allow forward flow and when the flow is halted, the disc swings back on to the seat to block reverse flow,” says MRS MD Franscois Steenkamp.

As the swing check valve is used to avert the reverse flow of fluids or gases, any failure can lead to leakage, contamination, loss of pressure and, in some cases, complete system failure.

“Cavitation damage is a form of hyper-erosion that can destroy both valves and piping, which can result in unacceptable process failures and also significantly shorten the life span of the valves in the system,” explains Steenkamp.

Having gained extensive experience servicing collieries around the Mpumalanga province, MRS has frequently made use of Belzona 1321 Ceramic S-Metal.

The solvent-free epoxy coating has “outstanding chemical resistance” and will bond to almost any rigid surface for the protection and refurbishment of metal surfaces subject to severe erosion-corrosion as found in coal mines.

Typical applications of this innovative protective coating include impellers, water box ends and flange faces. Steenkamp explains that valves are a very important part of any piping system and are not failproof.

“Once you have established that you have a faulty swing check valve or any other valve in the system, partnering with an experienced valve professional, such as MRS, can facilitate the selection and installation of the proper replacement, fully optimised to the client’s system.”

A fully refurbished pressure reducing valve needs to meet the high demands associated with a new product while saving on replacement costs. The system needs to ensure a reduction in high, unstable upstream pressure to maintain precise stable downstream pressure, regardless of changing upstream pressure or flow, and requires only existing line pressure to operate.

In another recent project, MRS refurbished a 10 inch pressure reducing valve showing signs of cavitation around the valve seat, which caused valve failure and a subsequent threat to the systems’ integrity.

“We found that the combination of a Belzona 1321 coating, and Belzona 1111 to rebuild the damaged areas, to be the most suitable in refurbishing the areas most affected by cavitation on the pressure reducing valve,” explains Steenkamp.

Belzona 1111 Super Metal epoxy is renowned for its high resistance to heat and wear. It is a cold-curing 100% solids epoxy composite reinforced with silicon steel alloy. This material can be used for various applications including bonding, shimming, forming, rebuilding, wrapping, patching, sealing and filling.