Many of those in HVACR are working to make the industry a better place, each in their own special way. For Arlyn L. (“Duke”) Moore, Reno Area technical director for Duke Craft LLC, making the industry better means inventing a product to make technicians’ jobs easier.


The Story of the Invention

Moore is the founder of Duke Craft LLC and the inventor of Duke’s Oil Drain Tool, a semi-hermetic compressor oil removal tool. He traces his history with refrigeration technology back to the 1970s, where he served aboard the USS Andrew Jackson, a ballistic missile submarine. There, he was introduced to all of the technology that makes submarines possible, including air tanks, water tanks, as well as air and fluid transfer using pneumatics and hydraulics.

“That was the first time I was ever exposed to tank fittings,” Moore said. “Which I later used when I first came up with the idea for my device.”

Following his service in the Navy, Moore was employed with various commercial refrigeration contractors, as well as a few of the industry’s refrigeration equipment manufacturers: Hussmann, Tyler and Hill Phoenix. He grew in his career path, at times responsible for a crew of technicians or tech support for a manufacturer, even some Advansor Booster direct expansion CO2 systems.

In the early ’90s, the HVACR industry went through a refrigerant transition that shifted away from chlorine refrigerants. Moore knew that switching the refrigerant (performing a retrofit) in a system involved changing the system’s oil multiple times. This nearly always caused a significant mess, as there was no convenient place to put a bucket to catch oil draining from a compressor. Technicians came up with their own solutions, sometimes rigging up a trough to drain the oil.

Moore looked at the problem and saw a solution: a tube with a tank fitting that screws into the side of a compressor, since almost all compressors have a ¼-inch NPT (national pipe taper) fitting on the side of them, for access to crankcase pressure.

“This product is very useful when performing the oil change, which is the first step in the process of a refrigerant gas retrofit procedure or gas change,” he said.

He explained how to use the tool: A technician pumps the compressor down to zero psi, as they normally would do to repair a leak or change a pressure control. Next, the technician removes the plug from the crankcase pressure port and screws Duke’s Oil Drain Tool into the side of the crankcase, insuring that the copper tube is in contact with the bottom of the crankcase. A clear plastic hose included in the package with the tool is attached to the drain valve and guided into a bucket. When the crankcase is pressurized again, the oil will leave the compressor, pass through the drain tool, and drain into the bucket without any sort of mess. The product can be used on a wide variety of semi-hermetic compressors, as well as a few scroll compressors and a few screw compressors. It works on compressors with both 45° and 90° crankcase pressure ports.

Moore said that his idea isn’t revolutionary — people have been using the general concept for over a 100 years when servicing equipment. He has seen technicians use crude versions of their own drain tools that they created themselves. But he hadn’t seen anyone designing and manufacturing efficient, easy-to-use, fully adjustable drain tools, so he took it upon himself to create one.


The Creation Process

Moore worked through the design of the product, testing various types of valves to see which ones allowed the oil to flow the best from the compressor. Schrader valves and needle valves didn’t work as well as he wanted, as they were slow and cause the oil to foam up. Full port valves, in contrast, did the trick, but in the end, he decided on a custom-made solution: a full port brass valve with a ¼-inch compression fitting on one side, and a ¼-inch flare fitting on the other with a knurled handle. This design allows technicians to change out the fittings quickly if the copper tubing gets damaged, even providing extra parts in the package. He also added a wingnut slide fitting that allows the drain tool to be screwed into a compressor easily even if someone’s hands are a little slippery from oil.

The products were initially made by hand in Moore’s garage until he found a manufacturer that could mass-produce them. Now, he’s working on selling the products to wholesalers, which will help the products get to his target audience of HVACR technicians.


The Complete Packaged System

Moore decided that to help introduce Duke’s Oil Drain Tool to his target audience of HVACR technicians, he would include a detailed set of instructions and a template for use.

By using Moore’s system, by taking a few measurements and following the instructions, technicians can pre-bend the copper tubing to fit almost any compressor. A four-foot clear plastic hose is included to anticipate the empty crankcase and prevent refrigerant venting.


Latest Product Improvement

Due to requests from customers, Moore has added a one-piece adapter fitting to be included in the package to reduce the “slide fitting,” in order to be able to fit the 1/8th inch NTP crankcase pressure ports found on the 1-½ hp and smaller semi-hermetic compressors.

The product can be viewed on Duke Craft LLC’s website.