An extremely simple Hermetically Sealed, Positive Displacement Linear Pump is presented that would electro-magnetically shuttle a floating piston inside of a tube. The proposed Linear Pump will eliminate potential leak paths and multiple maintenance problems for the LOX pumps at the Kennedy Space Center. The Linear Pump consists of only three parts and is based upon a Permanent Magnetic Linear Coupler, a linear motor, and a free-piston internal combustion engine. The three parts are: 1 or 2 free pistons that are electro-magnetically shuttle back & forth inside of a cylindrical linear motor and 2 or 4 check valves that control the direction of fluid. A leak-proof, low maintenance Linear Pump that can handle adverse conditions is immediately needed in the hazardous chemical, cryogenic and nuclear industries. The pump can operate in a stepper motor fashion and vary its pumping speed from maximum to 0% output. By connecting a linear shaft to the free piston, the Linear Pump can become an Electro-Mechanical Actuator or a combined Reciprocating Control Valve/EMA. By removing electrical power, the EMA could easily be back-driven. All moving parts (poppets on the check valves and the free-piston) operate within the confines of the sealed fluid. By replacing the poppet check valves with EMA valves, we can operate the pump as a small scale hydroelectric generator. POTENTIAL COMMERCIAL APPLICATIONS A highly economical, robust, low maintenance, hermetically sealed, Free Piston Linear Pump will have major advantages over most positive displacement and centrifugal pumps in applications where the fluid does not contain particulates that will prevent the proper operation of the check valves. The proposed hermetically sealed pump will eliminate all maintenance and hazardous emissions (and their clean air purges) associated with dynamic seals and rotary bearings. The proposed linear pump can be placed in-line of low viscous fluid systems and act as either the primary or the boost pumping system. By connecting a linear shaft to the free piston, the Linear Pump can become an Electro-Mechanical Actuator or a combined Hermetically Sealed Control Valve/EMA. The biggest reason why EMA?s are not being considered for use in the $2.5B per year Aerospace Actuator Market is that they can not be back-driven. By removing electrical power, the EMA could easily be back-driven.
