Low flow application, water hammering, improper selection or installation are all factors that contribute to swing check valve malfunctioning, wear, and ultimately failure.
Mechanical Rotating Solutions were called upon to repair a badly damaged swing check valve using its innovative Belzona 1321, a 2-part ceramic filled epoxy coating designed to provide erosion and corrosion resistance of metal surfaces.
According to Franscois Steenkamp, Managing Director of MRS, swing check valves use a hinged swinging disc to stop and control the movement of fluid in a system. “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 onto the seat to block reverse flow.”
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. During the refurbishment of the swing check valve MRS addressed the issue of cavitation around the valve seat causing valve failure and a subsequent 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 shortening the lifespan of the valves in the system. MRS addressed the cavitation issue by refurbishing their clients’ swing check valve by using Belzona 1321 (Ceramic S-Metal).” Says Steenkamp.
The swing check valve before refurbishment
Having gained extensive experience servicing collieries around the Mpumalanga province MRS has frequently made use of Belzona® 1321 (Ceramic S-Metal), This 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 includes impellers, water box ends and flange faces.
Valves are a very important part of any piping system and are not fail proof. “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 optimized to the client’s system.”
The swing check valve after refurbishment using Belzona® 1321
In another recent project, MRS refurbished an 10” Pressure Reducing Valve showing signs of cavitation around the valve seat causing 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. Belzona 1111 Super Metal epoxy is well known for its high resistance to heat and wear. Belzona 1111 (Super Metal) 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. A fully refurbished pressure reducing valve needs to meet the high demands associated with a new product whilst 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.