VFDs can cut costs and improve control

The paper on which this article is based was presented at the Institute of Hospital Engineering Australia’s (IHEA) 60th National Conference in 2009.

Medical suction has evolved over many years and, as technology has advanced, so has medical suction plant. Medical suction was achieved in its early days via handoperated devices similar to a bellows, followed by via mechanically-driven reciprocating piston pumps, which are still used today. The breakthrough came with the introduction of rotary technology, in the form of the liquid ring vacuum pump using water as a sealing medium. This technology has had several adaptations over the years, in that many different seal liquids have been used. The latest is glycol in a full liquid recovery system. The glycol is mixed with water and, as water evaporates in a vacuum, the systems require regular topping up. While there have been some very successful full oil seal systems, oil temperatures have to be kept under constant watch. The next significant advance was the advent of rotary vane vacuum pumps using oil as a lubricant. These pumps were equipped with oil mist eliminator exhaust filters to collect the oil vapour. In recent years advances have been made in many areas of engineering and industry, and the world of vacuum pumps is no exception. The advances in medical suction have been quite significant, and, coupled with the new technology in vacuum pumps, are quite innovative. This new technology has seen the use of new materials for manufacture, oil-free technology, much longer vane life, and increased pump efficiency. Also introduced have been claw pumps for general industrial applications.

Two key advances