Where was the last perforated tube you saw? Chances are, it was around the exhaust on a semi truck or a motorcycle. That’s an application where the tube does at least two jobs, and arguably, three. It muffles sound coming out the exhaust, it keeps fingers away from hot surfaces within, and it looks good. Exhaust systems are just one perforated tube application though: there are many others, usually out of sight. Here’s a look.
Perforated Tube Functions
To appreciate where and how perforated tubes are used it helps to understand how they work. Rather obviously, a perforated tube is a tube with holes. These holes let fluids pass through. The size and shape of each hole govern how easily and how quickly the flow takes place. In addition, the total area of holes, referred to as the “open area” controls the overall fluid flow rate.
Fluids can be liquids or gases. Liquid applications are often for filtration but can also be to control flow rate. Gas applications are often related more to how the gas transmits sound rather than filtration – acoustics, in other words.
Holes can pass more than fluids though. Heat and light are two examples, and then there’s also electromagnetic energy – radio waves or microwaves – which holes can filter.
Filtration – The Top Perforated Tube Application
Fluid filters, like those used in lubrication systems, are one of the most common applications for perforated tubes. However, the tube itself contributes little to filtration. In most systems there’s some kind of fine mesh material – a textile or maybe fiberglass or wire wool – that actually does the particulate trapping.
The role of the perforated tube is to support this filtration media, holding it in place and letting fluid flow. Hole size and open area are important in managing the fluid, particularly to ensure even distribution across the filter material. The holes themselves though are too big to filter any but the largest particles.
Flow Control Applications
Irrigation and drainage are examples of flow control applications. A pattern of small holes can regulate the rate at which water comes out of or can flow into a pipe. In addition, the oil and gas production industries use perforated tubing to manage fluid flow, and for a degree of filtration.
Like filtration, acoustic applications of perforated tubes work in two ways. Holes themselves let air transmit sound through the pipe, and the size of hole influences the frequencies passed and attenuated. However, in mufflers the perforated tube also holds the sound muffling material in place. Sound muffling perforated tubes are seen on trucks and motorcycles, but also on static engines and generators where the noise would otherwise cause a nuisance.
A second benefit of perforated tubing in a muffler is that, as an outer sheath, it prevents burns by keeping fingers and other body parts away from the hot inner piping. This guarding or shielding attribute is used in many similar applications involving heat or light where you want energy to pass through but in a safe manner.
Also under the heading of shielding, perforated tubes can protect something inside from electromagnetic radiation. Alternative, put the source inside the tube and protect what’s outside from electromagnetic interference (EMI.) (For an example, study the window in a microwave oven and you might notice that you’re looking through a piece of perforated metal with a very large open area. The holes let light through, so you can see in, but microwaves can’t get out.)
Architecture and Design
Lighting is another good perforated tube application. Here the perforation pattern can be engineered to create a wide variety of interesting effects.
Two related applications are architecture and interior design. With an almost limitless number of material and hole pattern combinations, (holes don’t have to be round,) perforated tubing can create countless interesting aesthetic shapes, patterns and textures. And don’t overlook the potential for custom perforation patterns that show off a logo or brand name!
The more you look for perforated tube applications, the more you’ll uncover. Two examples we’re proud of our work on the metal torch used at the 2006 Olympic games, and the pieces we supplied to NASA for the Mars Rover.
In the torch, perforations at the end of the tube let the flame engulf the body of the torch. That made it look like a traditional wooden torch. On the Rover mission, we supplied parts that helped ensure it touched down safely on the Red Planet. We “landed” that job because we’d previously supplied perforated tube for the Space Shuttle.
If the list of perforated tube applications seems long, the list of markets that use our tubing is even longer. From motocross aftermarket mufflers to paper milling, water treatment and oil fields in Azerbaijan, you’ll find it turns up in the most unexpected places.
Bring Us Your Applications
If you’ve noticed perforated tubes at all it was probably in a decorative application. Even on semi truck exhausts they’re largely decorative. As we’ve explained here though, applications go far wider. Really, any time there’s a need to regulate, restrict or control flow – of a gas, liquid or even light – a perforated tube might help. We’re always interested in new applications, so if you think you might have one we’d like to talk.