Inductive Pump

An Inductive pump is a magnetically regulated positive displacement pump used to pump liquids and gases. It is capable of handling many corrosive chemicals as well as solvents and gases. It is characterized by a single piston that reciprocates within a magnetic field and therefore doesn’t require a dynamic seal to link the piston to an outside mechanical power source. Check valves are placed at both ends of the piston housing allowing the simultaneous suctioning and pumping that reverses with each stroke. This is known to reduce pulsations especially at higher flow rates. The piston and housing are constructed of materials that are inert to many liquids and gasses. Because the piston and housing are non-plastic materials the positive displacement chamber does not change in dimension from flexing and distortion thus allowing inductive pumps to remain very accurate with no significant changes over time. Inductive pumps are extremely accurate as each stroke contains the same volume created by a solid piston inside a solid chamber. The number of strokes can be counted or timed to determine the total volume delivered. They can be used in sterile and controlled environments as they will not leak to the outside of the housing even if the piston has experienced wear.

Inductive pumps are considered highly accurate and energy efficient. Inductive pumps use two primary parameters to control flow, they are Rate and Dwell. Rate is used to determine the number of strokes per second or in any given time interval. Dwell is used to control the length of time the energizing coil remains on during the Rate cycle. Essentially if the piston has completed its stroke and is waiting for the reverse cycle to occur, there is no need to continue energizing the coil as most of this energy will be converted to heat as no more work is being done by the piston. The Dwell setting allows adjustment of this ON time during the rate cycle. Also the Dwell setting allows for a true pressure control parameter for the pump. By reducing the Dwell time even further one can reduce the total energy applied to the piston during the pumping cycle. This can reduce the maximum output pressure during pumping. This differs from many other pumps as they commonly reduce flow to reduce pressure in a given circumstance, however if an occlusion occurs to the output channel other pumps tend to build up to their maximum pressure until they either burst the tubing or damage their internal mechanism. Inductive pumps can be shut off at the outlet and will not exceed the pressure they are set at. Pumping against a close output does not cause damage to the pump.

The Inductive Pump was first patented in the United States by Laurence R. Salamey in 1998 U.S. patent number 5 713 728 and again in 1999 U.S. patent number 5 899 672. An additional patent has been filed for in 2014 by Salamey. The pump was originally designed as an improvement to peristaltic and diaphragm pumps as they were susceptible to fracturing of the pumping chamber with use due to their flexing of plastic parts. Inductive pumps were found to be an improvement to accuracy and length of service before repairs were required. Over time Salamey continued to develop his understanding of magnetic fields and their use for propagation of force with the inductive pump. This has led to further refinements and increased efficiency. Additionally inductive pumps have developed the ability to achieve much higher pressures in excess of 3,000 psi. The same inductive pump technology can be applied to very small pumps delivering volumes in the micro-liter range to much larger pumps delivering volumes in the 10 gallon per minute range. Understanding of magnetic field propagation has led to increased design simplicity which is a hallmark of inductive pumps. There are very few moving parts and no mechanical linkages. The piston is the only moving part aside from the check valves and it is driven by an electrically controlled magnetic field.

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Wikipedia