Students build high-vacuum system

Clay Rumsey, an applied physics major, explained on Tuesday to Weber State University students about his building of the high-vacuum system and how it works. This was part of a seminar where physics students show the projects they have worked on as a requirement.

Rumsey built from the ground up a high-vacuum system that varies in uses from industrial manufacturing to scientific research. Some of these uses involve thin film processes, car manufacturing, freeze-drying and manufacturing high-quality steels.

“We use vacuum for a lot of different things,” Rumsey said.

Rumsey started with a vacuum pump. John Sohl, a physics professor at WSU, picked up a used vacuum chamber for $2,500. An original cost for a new one would be $30,000.

Rumsey said the goal was to have a portable system, an easy-to-access chamber and a large chamber. Since he and the team he worked with kept changing the design on it, he created a 3-D model to figure out the problems that needed to be fixed.

“We can take this right into the shop and use it,” Rumsey said.

Rumsey said he needed a metal plate to hold everything together, but he had to be careful with scratches and avoid leaks. He had to keep fingerprints off the equipment as well as keep it from out-gassing and getting water vapor on the inside. Rumsey said the smallest scratches can still be a problem with getting particles into the system.

While Rumsey milled the plate, Rick Schroeder, another student at WSU, built the cart to mount the plate on and even painted it purple for school pride.

The next step was to rebuild the rotary vane pump, which cost $450, as opposed to buying a newer pump at $4,700. The pump pushes gas out while also pulling in gas pressure.

“After we fixed it, our pressure was almost at full magnitude, which was better than we had before,” Rumsey said.

The system requires oil. Rumsey said motor oil is not preferred because it has a lot of contaminants that can get into the system. For the mechanical pump, it would cost $65 per gallon of oil.

“We didn’t use that,” Rumsey said.

The system uses several gauges, such as the strain gauge, thermocouple gauge and an ion gauge. All of these are used to measure atmospheric pressure in the vacuum. With the ion gauge, molecular density is measured in the system.

Rumsey said in reality, they are fixing problems. It’s never in true equilibrium, and there will almost always be a leak. He is trying to prevent outside leaks using a detector on loan from the University of Utah.

In the end, Rumsey said, he put 800-1,000 hours into building this system. He has plans for future use of the system, involving more automation to the system, mounting hardware on it and bypassing the diffusion pump. He can do a variety of things with the system.

“The idea is not to just have a thing that’s not just a student project, but a lot of students from here on out can use this,” Rumsey said.

Rob Lemmons, a WSU freshman majoring in electronics, said he was able to follow everything.

“I like to come out and see things like this, even if I don’t understand it,” Lemmons said. “It’s not just numbers on a chalkboard. It’s actually how you take this from a chalkboard and make this something real.”

Roger Saunders, a former major in physics, said he thought it was cool how the team saved huge amounts of money by building the system and still could have problems even if they bought it new.

Saunders said he plans on going to more of these seminars.

“I keep checking the Internet for them,” Saunders said.

The WSU Physics Department posts its events on the WSU calendar, and there are more to come.