PROBLEM: Melted pipework in pretreatment tunnel

A UK engineering firm contacted SNP due to issues in a client’s pre-treatment tunnel for vehicle painting.

During some planned maintenance, pipework had been replaced with product found in stock which SNP had previously supplied. After restarting the process, the pipework used to replace the original pipework had melted, as per the image below.

The engineers could see the problem was confined to Stage 1 of the tunnel where temperatures were highest.

THE DIAGNOSIS

Having supplied the original pipework, and due to the fact that the coloured components of the system used are easily identifiable, SNP engineers were able to confirm immediately that the pipework was made in polyvinyl chloride (PVC).

This was as specified and intended by the client for use in Stage 4 of the tunnel where temperatures were lower.

However, the correct pipework for Stage 1, where temperatures could reach 80°C, was specified and supplied in chlorinated polyvinyl chloride (CPVC).

CPVC, a thermoplastic produced by chlorination of PVC, is able to withstand higher temperatures (up to 100°C) than standard PVC (up to 60°C). SNP also identified that, in one area, the 1¼” pipework was connected to 1½” pipework which would also have impacted the process.

THE PRODUCT

SNP are the exclusive European distributors for the industry-leading Uni-Spray pre-treatment spraying system used in the client’s spray tunnel. The Uni-Spray range consists of nozzles, quick-release adjustable nozzle holders, complete risers, quick-release pipe couplers and pipe supports.

Uni-Spray is the manufacturer that initially led the move 20 years ago from stainless steel spraying systems to high-quality plastics. Uni-Spray’s Quik-Disconnect Riser Assemblies are made exactly to client specifications and are ready to install. They aim to make the operation and maintenance of pre-treatment tunnels as simple as possible, using tough, durable components which are adjustable, colour-coded and can be disconnected quickly and easily.

Uni-Spray products come in a large range of sizes and materials. As well as PVC and CPVC, versions are available in PolyPro, Kynar and stainless steel. The pipework can also undergo custom bending to precisely meet clients’ design configurations.

CONCLUSION

SNP was able to quickly supply new CPVC pipework to get the process up and running again. The Uni-Spray system remains the most comprehensive on the market, suitable for all sizes of pre-treatment tunnels. Care must be taken during maintenance, however, to ensure effective performance.

Correctly installed, the benefits of the Uni-Spray system include:

• Easy to specify
• Easy to identify and replace components
• Robust and available in a range of materials, making it suitable for even harsh environments and high temperatures
• Quik-Disconnect system reduces maintenance downtime
• Cost-effective