Compressed Air Fail: The Quick Tool Test

A fiberglass parts manufacturer was having problems with its tools. Despite repeated replacements, its grinding and cutting tools just weren’t performing well; they lacked power and were causing reduced productivity. The tool supplier was contacted to reach an acceptable solution. He, in turn, contacted a compressed air auditor to see if anything could be done.

 The auditor did a quick walkthrough and spotted some obvious problems. The plant personnel, it seemed, loved retractable 50- and 100-ft hose reels—because they kept the tool hoses all nicely rolled up and off the floor. To increase the flexibility and ease of connection, they connected these reels to the main piping system using two 1/4-in. quick couplers, on each end of an interconnecting hose. Some of the hoses were a bit too short, so another section of hose was connected using 1/4-in. quick couplers. And at the end of the hose one more quick connect coupler was used.

The air auditor fashioned a simple test connection, a T with a gauge on it, to detect how much pressure the tool was actually getting when it was running. With the tool off and no flow in the hose, the pressure was 118 psi. With the trigger pulled, the pressure at the tool was 44 psi. For adequate performance, this tool requires an operating pressure above 90 psi.

An experiment was performed where only one full flow quick connect coupling was used at the tool, with the same size hose but the hose reel removed. All other connections were replaced with threaded standard fittings. This time, when the tool trigger was pulled, the pressure fell to 92 psi at the tool, still a significantly high pressure drop of 26 psi, but enough to allow proper tool performance. The employees liked the performance so well that they refused to allow the auditor to remove his full flow connectors.

Plans are to upgrade to various sized hoses matched to the connected tool, with a target pressure differential of less than 10 psi. This improvement will allow the compressor pressure to drop by 10 psi, saving on air compressor power (every 2 psi reduction saves 1% power) and artificial demand (every 1 psi reduction reduces flow about 0.9%).

A quick took tester made of parts totaling less than $100 can save thousands of dollars.