Pumps are devices used to move fluids, such as gases or liquids. Displacement of fluid is achieved by physical or mechanical means. Pumps may be used to evacuate gas from a confined space, thereby creating a vacuum. Conversely, pumps may also be used to draw in gas from one environment to another. In another example, pumps may be used to pressurize a sealed volume or to generate a pressure gradient along a restricted flow path.
Most pumps are not suitable for miniaturization as they possess mechanical parts or require a low backing pressure that makes it necessary to use a backing pump. Miniaturized pumps, such as micropumps and mesoscale pumps, can suffer from poor performance and reliability, or introduce undesired vibrations into a system.
Thermal transpiration pumps work by maintaining a temperature difference across an orifice under rarefied conditions. However, there is room for improvement in throughput, range of pressure under operating conditions, operating voltage, energy efficiency, and other aspects affecting cost, manufacturability and performance.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent upon a reading of the specification and a study of the drawings.
USPTO Backgrounds
USPTO Backgrounds