The oil and gas industry needs a simple and compact pump that could deal with slurry and other highly viscous or erosive fluid. The pump should also be able to fit in limited space of a borehole while maintaining comparable or higher efficiency than the current applications. Inspired by the algebraic screw, a new design of power transmission device, named as Transmission Roller, is introduced in this work and incorporated into a diaphragm pump. This mechanism converts rotary motion into linear motion and shows promises of high efficiency with its compact structure. Similar mechanisms have never been used in a hydraulic application before. A pump prototype utilizing the Transmission Roller is built and tested with water to prove its functionality. The transmission efficiency of the transmission roller prototype is 73.6%. The Transmission Roller efficiency for the final production pump design is expected to be 96.3%, higher than other designs of the same kind.