When designing a compressed air pipeline, remember that size matters. The internal size of the pipe, along with the pressure and air volume, determine the velocity of the compressed air in the pipeline. The higher the velocity, the higher the pressure drop in the pipe work from the compressor room to the point of use. High-pressure drops increase your energy costs and affect production rates.
What generally happens is that shop floor staff complain about low compressed air pressure. This leads to operators increasing the air compressor’s discharge pressure, which in turn means that for every 1 bar increase in pressure, you are paying an extra 7% on your power bill. The increase in pressure will also increase the discharge temperature and the wear and tear on the compressor, and may also affect the air/oil reclaimer life span.
This is when bigger is better. Do not use 15 m/s as a guide for main line sizing. Use the 6 m/s selection guide. These guides are for bar applications, which will change if the pressure is lower or higher. Slower air velocities equate to lower pressure drops. This means better compressor performance and less power wasted. Use the higher speed chart for very short air take-off points only, nothing else.
The charts do not show the pressure drops for valves, bends, tee pieces or flex hoses. These charts are merely a guide – treat them cautiously. The manufacturers of compressors often set a bad example for pipe sizing. We frequently see very small undersized outlets on air compressor packages. This suits the manufacturer as the piping is cheaper and easier to fit into tightly engineered compressor packages.
Check the charts above and oversize the piping accordingly, especially in the compressor room. Low speed equates to less back pressure. High velocities and bad pipe design lead to compressors bouncing from load to unload. This is not good for the controls, the filtration system, the air dryer or the compressor system itself.
Use a correctly sized air receiver to act as a buffer between the compressor and its ancillaries, such as dryer and filters. This will reduce your load and offload cycles and improve compressed air quality. High velocities and pressure drops in the compressor room frequently lead to the air compressor fighting for lead position or control. If possible, install a compressor controller where you determine the lead and lag air compressor as it will generally save you a small fortune on energy costs, compressor repairs and maintenance. Lower air speeds also improve compressed air filtration and reduce pressure drops across the filter bank.
Call us for a copy of ‘Compressed Air Piping Design Hints’.
PC-based control for additive machine tools Beckhoff Automation
Editor's Choice Electrical switching & drive systems & components
IRPD is a specialist in additive machine tools. Development is heavily focused on high system throughput and consistently high process quality. This goal was achieved with the help of PC- and EtherCAT-based control and drive technology from Beckhoff.
Read more...A guide to common hydraulic system contaminants CT Hydraulics (Nqoba)
Editor's Choice Hydraulic systems & components
Every engineer, machine designer and maintenance professional understands that the heart of any reliable hydraulic system is its fluid. But the moment that fluid is compromised, your system’s life expectancy and your peace of mind drop dramatically.
Read more...Top questions about pressure gauges SA Gauge
Editor's Choice Pneumatic systems & components
Some questions never go out of date, and in our industry, a few have been asked for decades. At SA Gauge, we hear them every week. Here are the ten questions we hear most often, and the practical answers that can save time, money and frustration.
Read more...A technological leap with the proportional valve terminal Festo South Africa
Editor's Choice
Festo continually makes bold technological leaps to keep pace with global advancements. Controlled Pneumatics is redefining the boundaries of compressed air technology to meet the demands of today’s most advanced applications.
Read more...PC-based control optimises robotic parts handling on plastics machinery Beckhoff Automation
Editor's Choice
NEO is a cartesian robot developed by INAUTOM Robótica in Portugal for parts removal on plastics machinery. Its aim is to increase system productivity. NAUTOM Robótica has entered into a strategic partnership with Bresimar Automação to increase the working speed of the cartesian robots using advanced control and motion solutions from Beckhoff. The result is a comprehensive, future-proof automation solution for its entire family of cartesian robots.
Read more...Heavy impact, smart control Axiom Hydraulics
Editor's Choice Hydraulic systems & components
Every now and then a project lands on your desk that’s equal parts heavy machinery and fine control - a tantalising mix for any engineer. A client approached Axiom Hydraulics with a project exactly like this.
Read more...Driving fluid power forward
Editor's Choice
The National Fluid Power Association is developing its latest Industrial Technology Roadmap for 2025, showing how hydraulics and pneumatics are changing to meet new industrial demands.
Read more...World’s hottest engine
Editor's Choice Electrical switching & drive systems & components
Scientists have built the world’s smallest engine. It’s also the world’s hottest. It could provide an unparalleled understanding of the laws of thermodynamics on a small scale, and provide the foundation for a new, efficient way to compute how proteins fold.
Read more...Reinventing the wheel
Editor's Choice Electrical switching & drive systems & components
Once a curiosity in the early automotive age, in-wheel motors are now re-emerging with real promise. From electric cars to commercial vehicles and even aircraft, they are on the verge of transforming transportation engineering.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version