Our representative in Virginia, PBE Inc., asked me to make a call with them to try and solve the customer’s compressed air problems. The primary products produced at this facility are apple juice and apple sauce. Problem: Product rejections resulting from wet compressed air downstream of the dryersįor this troubleshooting call, I visited an apple processing plant in the Shenandoah Valley region of northern Virginia. Case 2: Product rejections resulting from wet compressed air downstream of the dryersĪpplications: Dry 300 scfm of compressed air to -40 FPDPĭry 700 scfm of compressed air to +35FPDP A systems approach finally led me to the source of the trouble. In this case the lack of dry air had nothing to do with the dryers. Sometimes the problem is where you least expect it to be. Once I closed the by-pass valve and dried out the sample cell on the plant’s dew point meter, the dew point came back into specification.Įven though I eventually solved the problem, I should have looked at the piping and valves sooner. Take note: Wet Compressed air + Dry Compressed air = Wet Compressed Air. Wet air upstream of the dryer was escaping past the dryer, mixing with the dried air. So I went back and traced all the piping between the compressors and the dryers. The customer strongly believed that our dryers were not performing. After this, I fast cycled the dryer to make sure it was sequencing properly. This dryer operates on an 8 hour cycle(4 hours drying, 4 hours regenerating) so I had to wait for an hour or so to make sure the regenerating tower was coming up to the proper temperature. I then asked the customer to bring the HB-5000 blower purge dryer on line. So how was moisture appearing downstream of the dryer? The puzzle was still not solved. In this case, the moisture indicator on the dryer was blue. Pink crystals indicate that wet air is exiting the dryer. Blue crystals mean the dryer’s outlet air is dry. This is a small clear tube filled with color changing silica gel crystals. Next, I looked at the visual moisture indicating stick on the dryer’s gauge panel. Too much pressure in a regenerating tower of heatless dryer causes problems. I needed to confirm that the each tower pressure gauge read zero during regeneration. Now, I watched the heatless dryer to make sure it was cycling properly. Next, I checked the automatic condensate drains on the after-cooler separators and pre-filters. I started by looking at the compressors to confirm operating pressures, temperatures, and flow rates to the dryers. Had I been in his shoes, I’d have felt the same way. The customer insisted something was wrong with our dryers. Still wet air was somehow getting downstream.
The operator then put heatless dryer on line. When I arrived on site, the customer told me that he could not maintain the specified -40 dew point with the blower purge dryer. This customer has a 5000 SCFM Van Air Systems, model HB-5000, externally heated blower purge dryer and a 5000 SCFM Van Air Systems, model HL-5000, heatless dryer as a backup. Case 1: Wet air downstream of the dryerĪpplication: Dry 5000 scfm of compressed air to -40F Pressure Dew Point (PDP) Here are some descriptions of a few recent troubleshooting calls I have personally made, where the systems approach worked well. This means looking at a complex range of problems and solutions, not just what you suspect the problem to be. The key to helping the customer is to take your time and properly analyze the installation. I first try find a solution over the phone, but sometimes it actually requires a on-site inspection of the customer’s plant air system.
Over the years we have built a great reputation for helping customers solve issues with their compressed air systems regardless of what brand equipment has been installed. I get calls on every make and model imaginable.
I’m asked quite often to troubleshoot compressed air dryers when they're not working.
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