Turbomolecular Pumps

Turbomolecular pumps (TMP) for ultra-high vacuum are known as THE application for AMBs. Whereas contamination-free operation could be achieved by other bearing technologies none of them is suited to operate under vacuum conditions. The very particular shape of a TMP turbine, with or without Holweck stage, makes for highly gyroscopic systems that simply cannot be realized with analog or basic control approaches. MECOS has long standing experience of providing digital controllers for turbomolecular pumps with suction rates of well above 2000 l/s where the size of the turbine wheel exacerbates the challenge of robust and stable operation.

Turbomolecular pumps furthermore face a variety of very stringent requirements such as

Very low levels of vibration during operation
Resistance to corrosive gases
Small footprint of the equipment

and they are typically deployed in larger numbers making integration into an existing communication environment at the customer site a necessity.

The design of the MMC2A, digital on-board controller for the HiPace MC is a fine example of cooperation between MECOS and Pfeiffer Vacuum where multiple mechanical and electrical interfaces had to be managed and where integration of the magnetic bearings into the pump required close cooperation.

Oil-Free Down to the Last Molecule

In the case of Pfeiffer Vacuum's HiPace MC contamination-free and ultra-high vacuum operation certainly where key requirements. The design challenge of this machine consisted of integrating the complete AMB and motor control unit into the pump in order to reduce the footprint of the equipment and to avoid cable connections. The resulting control unit MMC2A now directly sits on the pump and is cooled by the pump's water circuit. Connection to the cartridge is achieved by a vacuum-tight circular connector.
Photo courtesy Pfeiffer Vacuum, Asslar, Germany.