How To Prevent Pressure Drops

Issue 1

Compressed air serves as the essential utility for operation, and its performance limitations are determined by the supply available. To effectively utilize EXAIR products and pneumatic equipment, it is crucial to establish a method for transferring compressed air from the source to the point of use. This can be accomplished through three primary means: pipes, hoses, and tubes.

As compressed air travels through the distribution system, it experiences friction against the inner surfaces of pipes, tubes, and hoses. Factors such as the diameter of the pipe, its length, the number of bends, and the smoothness of the inner wall contribute to this friction. Consequently, a reduction in air pressure occurs due to this resistance. Additionally, pressure drops can also happen at the point of use, particularly if the line is inadequately sized, which can significantly affect the performance of the equipment being powered.

When designing and maintaining a compressed air system, it is essential to take pressure measurements at various locations to detect and resolve potential issues before they escalate. The Compressed Air Challenge recommends specific points for regular pressure assessments to accurately gauge the operating pressure of your system.

  • Inlet to compressor (to monitor inlet air filter) vs. atmospheric pressure
  • Differential across air/lubricant separator
  • Inter-stage on multistage compressors
  • After-cooler
  • At treatment equipment (dryers, filters, etc.)
  • Various points across the distribution system
  • Check pressure differentials against manufacturers’ specifications. If high pressure drops are noticed, this indicates a need for service.

After taking the necessary measurements, you should sum the recorded pressure drops and subtract this total from your compressor’s operating range. The resulting value represents the actual operating pressure at the point of use.

If your distribution system is correctly sized and the pressure drops across your equipment are within acceptable limits, any pressure drop observed at the point of use suggests a lack of sufficient air volume. This issue may stem from restrictive fittings or inadequately sized air lines, hoses, or tubes. It is essential to ensure that the point of use product is installed in accordance with the manufacturer’s specifications for compressed air.

If you have questions about pressure drops, or anything regarding EXAIR and our products, please do not hesitate to reach out.

Jason Kirby
Application Engineer
Email: jasonkirby@exair.com
Twitter: @EXAIR_jk

Preventing Pressure Drop in a Compressed Air Distribution System

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

Compressed Air and Pressure Drop: Explained

A critical component to optimal performance of any compressed air operated product is ensuring sufficient compressed air flow. Simply put, inadequate air flow won’t allow you to get the job done.

 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 finished surface of the inner wall all play a part in this. 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 line is undersized, this pressure drop will be great enough to impact the performance of the product. 

When designing and maintaining your compressed air system, pressure measurements should be taken at varying points to identify (and fix) any issues before they create a greater problem down the road. According to the Compressed Air Challenge, these are the places you should take regular pressure measurements to determine your system 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
  • At treatment equipment (dryers, filters, etc.)
  • Various points across the distribution system
  • Check pressure differentials against manufacturers’ specifications. If high pressure drops are noticed, this indicates a need for service.

*More recent compressors will measure pressure at the package discharge, which will 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. This could be due to restrictive fittings or undersized air lines, hose, or tube. Check that the point of use product is properly plumbed to compressed air per the manufacturer’s specifications.

EXAIR Products are designed to minimize this pressure drop by restricting the flow of compressed air. The more energy (pressure) that we’re able to bring to the point of use, the more efficient and effective that energy will be. 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 up the line. In the other photo with a modular style hose, some pressure is able to build up but if it gets too high the hose will 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, keep the compressed air 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. 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

Optimizing Compressed Air: 6th Step – Lower the Pressure!

The last step in EXAIR’s Six Steps to Optimizing Your Compressed Air System centers around air pressure. Unless you’re controlling your air pressure for each individual application, there’s a strong chance you can achieve quite a bit of savings by lowering the air pressure just upstream.

In any application necessitating the use of compressed air, pressure should be controlled to minimize the air consumption at the point of use. Pressure regulators are available to control the air pressure within the system and throttle the appropriate supply of air to any pneumatic device. As the last of the six steps to optimizing your compressed air system, controlling air at the point of use can often be overlooked.

Pressure Regulators “dial in” performance to get the job done without using more air than necessary.

Pressure regulators utilize a control knob that is turned to either increase/decrease tension on a spring. The spring puts a load on the diaphragm which separates internal air pressure from the ambient pressure. Typically made of a flexible rubber material, these diaphragms react very quickly to changes in the air supply. By either increasing or decreasing the flow of air based on the load on the diaphragm, downstream pressure remains fairly constant.

While one advantage of a pressure regulator is certainly maintaining consistent pressure on your compressed air devices, using them to minimize your pressure can result in dramatic savings to your costs of compressed air. As pressure and flow are directly related, lowering the pressure supplied results in less compressed air usage. EXAIR recommends operating your Intelligent Compressed Air Products at the minimum pressure necessary to achieve a successful application. If you notice a desirable result at a pressure of 60 PSIG, or even less, there’s no need to run full line pressure. In-line point of use pressure regulators are the simplest and most reliable way to allow you to dial down the pressure for any compressed air operated product.

When selecting a pressure regulator for your application, it’s critical that it is appropriately sized to supply adequate volume to the point of use devices downstream. Doing so, minimizes the risk of experiencing “droop”. Droop is a decrease in outlet pressure from the specified setting due to an increase in flow rate.  Droop occurs when the demand at the point of use exceeds the volume of air that the regulator can supply. By ensuring the pressure regulator is rated to deliver a sufficient volume of air, you’ll reduce the chances of experiencing droop. EXAIR offers pressure regulators in kits along with many of our products. We’ve done the hard part for you and made sure they’re properly sized!

If you’re looking for ways to help lessen the demand on your compressor, EXAIR’s team of Application Engineers will be happy to help. Reach out to us via phone, chat, or e-mail and see for yourself just how easy it can be to start saving compressed air!

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD