Types of Tubing for Pneumatic Applications
When designing a pneumatic system, there are many options for the system’s tubing. Depending on its use, the tubing material could vary widely.
The five most common types of tubing are polyethylene, nylon, urethane, copper, and stainless steel.
For many years polyethylene was the most common type of pneumatic tubing due to its low cost, flexibility, and wide range of color-coding options. It is suitable for most push-to-connect fittings, compression fittings with a plastic sleeve, and some barb fittings. However, polyethylene will kink if bent too far, and is only rated to 80-125 psi depending on its size. Other drawbacks include limitations in temperature and chemical compatibility, and the tubing wall’s ability to wear out and fall out of a push-to-connect fitting due to its softness.
Nylon tubing is more expensive than polyethylene, but its higher price brings many advantages. It has a harder wall, a wider range of chemical compatibility, and a wider window of operating temperatures. It can also be purchased in different thickness and hardness, providing higher operating pressures up to 400 psi. However, due to this added toughness, nylon is generally less flexible. As such, it requires more room to bend and is usually only found on the interior of pneumatically actuated equipment. Though it is available in many colors, nylon is naturally transparent, making it an ideal replacement for glass in level gauges on tanks.
Urethane tubing is the most flexible of all types. It has a soft wall, making it easy to use in tight routes. It is also popular for its aesthetically-pleasing characteristics, as it is available in a wide array of bright colors to match many machines. It is slightly more expensive than polyethylene, but unless you are buying it in large quantities, the price difference will likely be marginal. The softness of the wall, which brings the advantage of high flexibility, also brings disadvantages, such as low pressure and the potential for lack of compatibility with push-to-connect fittings where urethane is inideal. Push-to-connect applications often call for a harder tubing with a heavy wall, as this can increase the pressure drop through the tube.
Copper was the original material used in pneumatic tubing, but was largely replaced following the introduction of plastic and push-to-connect fittings. Nevertheless, there are still certain applications where the rigidity and durability of copper proves advantageous. For extreme applications, stainless steel can provide temperature and chemical resistance capabilities beyond those of plastic. Stainless steel, combined with instrumentation style compression fittings, is often worth the extra cost and effort when used in critical or harsh applications.
The three most important factors to consider when choosing one of these materials are flexibility, compatibility, and cost. Additionally, before choosing a material, it can be helpful to consider the acronym S.T.A.M.P., which stands for Size, Temperature, Application, Media, and Pressure. If all of these factors are taken into account, you can be pretty certain your pneumatic system has safe and reliable tubing. Once you have made your decision, the final step is to get your tubing from a trusted source. For tubing of all types and much more, look no further than ASAP Aviation Procurement.
Owned and operated by ASAP Semiconductor, ASAP Aviation Procurement can help you find all types of parts for the aerospace, defense, civil aviation, electronics, IT hardware, and industrial markets. Our account managers are always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@asap-aviationprocurement.com or call us at 1-714-705-4780. Let us show you why we consider ourselves the future of purchasing.