14. Evaluate Surface Characteristics
Surface characteristics can also play a role in tubing selection. Questions to consider include: Does the tubing or hose need to have a mirror-smooth interior surface for efficient transfer with little to no friction? Will it transport granular materials, dry powder, or another substance where the surface condition is not a crucial matter? What about the outside? Should it be smooth, or does it need a surface texture like ribbing to make it easy to grip and hold on to? Surface properties can also affect electrical conductivity and static dissipation.
15. Consider Weight
Some single-layer tubing is very lightweight and a perfect match for applications where overall weight is a concern. Some hoses are multilayered and heavy. Add metal fittings and clamps to form an assembly, and that increases the weight. The overall weight of the tubing, hose, and/or assembly components used in an application needs to be considered. It is essential that the hose assembly's weight does not pull on other equipment.
16. Check for Abrasion Resistance
If the application involves rubbing of the tubing or hose against other equipment, it is critical that both the tubing or hose and, of course, the other equipment can withstand that abrasion. Certain tubing materials like polyurethane are better suited to abrasion resistance than others (silicone, for example). Corrosion resistance is another concern that is sometimes overlooked. Perhaps the liquid in the application is acidic. If so, it needs to flow through tubing or hose that can withstand it. Consider, too, the environment the tubing or hose will be in and whether corrosive fluids will come into contact with the tubing or hose.
17. Research Alternative Materials
Research each need individually to make sure the application is not being overengineered or that the tubing or hose is more than what is needed. Also consider coextrusions, which can save costs. Sometimes demanding performance characteristics required for the inside of a hose can differ from those needed on the outside. Hytrel®-lined PVC is one example — oil-resistant Hytrel makes up the interior while durable PVC protects the outside.
18. Know Packaging Requirements
Packaging should also be considered. It can dictate whether a 100-ft coil of tubing or hose acceptable or whether 20 straight pieces, each five feet long, is more appropriate. Consider whether it must it be bagged, double bagged for extra cleanliness, or boxed, or whether stacked coils on a wooden pallet are acceptable. Knowing how the tubing or hose will be used can help determine your packaging needs, allow for easier handling, and result in less waste. The product can be packed so that it's ready to use upon delivery.
19. Explore Custom Options
This can relate closely to packaging requirements. For instance, if the end use of the tubing or hose requires that it be cut into 6-in. pieces, why not have it delivered that way? Other customization can include special colors, heat-formed shapes, thermally bonded tubing, printing, coiling, molded components, or hose assemblies. Don't consider only stocked products — know the ultimate use of the tubing or hose to determine whether a custom product will save time and cost.
20. Don't Forget about Fittings and Clamps
In most cases, the tubing or hose must be attached to other equipment. Fittings and clamps come in many different materials — from nylon to PVDF, fluoropolymer to brass — so it is important to select the best match for the application. For some applications, a system can be built from one material (polypropylene, nylon, polyethylene, or fluoropolymer). Remember that the fitting's material must also be compatible with your application.
For any given medical application, it is important to consider everything from chemicals to flexibility when selecting the tubing. Applying the tips described above should help designers select the right tubing, avoiding situations that can lead to downtime add unnecessary cost.
This article was written by Alex Kakad, Product Manager for NewAge Industries, Southampton, PA. For more information, visit here.