An emergency call was placed to a compressed air auditor recently to help solve a problem with a new collating machine at a local printing. This plant had previously upgraded their compressed air system to state-of-the-art variable speed drive control and had been able to drop their plant pressure by 20 psi due to the resulting very precise pressure control.
The collator was installed during a plant shutdown the previous weekend and was having major problems. The only way the production team was able to get it to work was to jack the main plant compressed air pressure by 25 psi. But even then, there were still issues requiring even higher pressure than the compressed air system could reliably supply.
The auditor arrived and very quickly discovered a problem by watching the main pressure regulator on the input of the collator. Each time the main pneumatic actuators within the machine changed state, the pressure indicator on the regulator dropped from 110 psi down to 50 psi. This indicated a significant pressure restriction between the main compressed air line feeding the machine and the regulator. In their haste to install the collator, the plant personnel had used standard 1/4-in. rubber hose to connect to the main line. The hose had standard issue quick connect couplers on each end adding to the pressure differential.
An analysis of the collator showed that the actuators consumed quick pulses of air that required 1/2-in. or larger feed lines. The 1/4-in. feed lines were standard issue for the plant. Due to a purchasing policy for compressed air, the plant did not stock any larger fittings in their stores for use for machine and tool hook-up. In this case, the policy proved to be short sighted and was costing the company significant amounts inlost production and was increasing the compressed air costs about 10% due to higher pressure.
The fittings and hoses were eliminated and the machine was hard piped into the main compressed air supply. The plant pressure returned to normal.
Learn more about solving pressure differential problems in the Compressed Air Challenge webinar scheduled for November 2013. Visit www.compressedairchallenge.org for more information.
By Ron Marshall for the Compressed Air Challenge
Filed Under: Pneumatic Tips