A critical component to optimal performance of any compressed air-operated product is ensuring sufficient compressed air flow volume is available. Simply put, inadequate air flow won’t allow you to get the job done. When troubleshooting an application for EXAIR Products, the vast majority of problems occur due to pressure drops in the system not allowing the product to work optimally. Oftentimes, this can be something as simple as using an undersized air hose or supply line. Imagine trying to suck a thick milkshake through a coffee stirrer, compared to a wide-mouth straw. You’re not going to have much success with a coffee stirrer, but the increased cross-sectional area of the wide-mouth straw allows you to suck it up and enjoy it comfortably. The same concept is true for supplying air to your products. If there’s a restriction, it won’t work properly! Let’s talk about what you can do to ensure you’re operating effectively.
As compressed air moves through the distribution system, it encounters friction inside the walls of the pipe, tube, hose, etc. The diameter of the pipe, length, number of direction changes, and surface finish of the inner wall all play a part in the total amount of friction applied. A drop in air pressure will occur as a result of this friction. In addition to pressure drops experienced due to the distribution system, they can also occur at the point of use. If the compressed air supply line is undersized, the pressure drop will manifest and be great enough to impact the performance of the product.
When designing and maintaining your compressed air system, pressure measurements should be taken across varying points to identify (and fix) any issues before they create a greater pressure drop problem down the road. According to the Compressed Air Challenge, these are the places you should take regular pressure measurements to determine your system’s net operating pressure:
- Inlet to compressor (to monitor inlet air filter) vs. atmospheric pressure
- Differential across air/lubricant separator
- Inter stage on multistage compressors
- After cooler
- On treatment equipment (dryers, filters, etc.)
- Various points across the distribution system
- Check pressure differentials against a manufacturer’s specifications. If high pressure drops are noticed, this indicates a need for service on the affected equipment.
Newer compressors will measure pressure at the package discharge, which would include the separator and after cooler.
Once you’ve taken these measurements, simply add the pressure drops measured and subtract that value from the operating range of your compressor. That figure is your true operating pressure at the point of use.
If your distribution system is properly sized and the pressure drops measured across your various equipment are within specifications, any pressure drop noticed at the point of use is indicative of an inadequate volume of air being transmitted across the distribution system. This could be due to restrictive fittings or undersized air lines, hose, or tubing. Check that the point of use product is properly plumbed into the compressed air supply per the manufacturer’s specifications.
EXAIR Products are designed to minimize this pressure drop by restricting the flow of compressed air at the point of use. The more energy (higher pressure) that we’re able to bring to the point of use, the more efficient and effective that energy will be at operating point of use equipment. The photo below shows two common examples of inefficient compressed air usage. With an open-ended blow off, a pressure drop occurs upstream inside the supply line. If you were to measure the pressure directly at the point of use, while in operation, you’d find that the pressure is significantly lower than it is at the compressor or further upstream in the compressed air distribution system. In the other photo, with a modular-style hose, some pressure is able to build up. But if it gets too high the hose connection can blow apart. These types of modular style hose are not designed to be used with compressed gases.
EXAIR’s Super Air Nozzles, on the other hand, restrict compressed air volume flow to a lower level to keep the compressed air pressure high, right up to the point of discharge, and minimize the pressure drop. This, in addition to the air entrainment, allows for a high force while maximizing efficiency by reducing the amount of air consumed. If you’d like to talk about how an EXAIR Intelligent Compressed Air Product could help to minimize pressure drop in your processes, give us a call.
Tyler Daniel, CCASS
Application Engineer
E-mail: TylerDaniel@EXAIR.com
X: @EXAIR_TD
