An injector generator for use in geomechanical pumped storage systems includes a power end and a fluid end. The fluid end has one or more fluid chambers each having a fluid inlet and outlet that are controlled by rotary valves. The fluid end can function as a pump or as a motor driven by fluid pressure from the geomechanical storage formation.

A diaphragm pump assembly can include a pump drive chamber, a first pump diaphragm chamber, and a second pump diaphragm chamber. The assembly can include a pump motor configured to rotate a motor shaft extending into the pump drive chamber. The assembly can include a cam connected to the motor shaft and configured to rotate in response to rotation of the motor shaft. The assembly can include a drive yoke having a yoke frame and a yoke pocket having a first wall and a second wall parallel and opposite the first wall. First and second pistons can connect to the drive yoke and to first and second diaphragms, respectively. The diameter of the cam can be less than and within 5% the width of yoke pocket and the yoke can be configured to move the pistons along a straight line.

Peristaltic pumps are described herein. In certain embodiments, a peristaltic pump includes a plunger, a first biasing member, and a second biasing member. The plunger is movable to selectively engage a pumping volume of a tubing segment to expand the pumping volume to draw fluid flow into the pumping volume and to contract the pumping volume to conduct fluid flow from the pumping volume. The first biasing member is configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment during the expansion of the pumping volume. The second biasing member is configured to urge the plunger toward the tubing segment to contract the pumping volume.

A fluid system may include a first fluid path including a blender configured to mix fluid with proppant. The fluid system may include a second fluid path, fluidly isolated from the blender, including a pump. The fluid system may include a mixing pump configured to receive first fluid containing proppant from the first fluid path and second fluid free of proppant from the second fluid path. The mixing pump may include a cylinder defining a bore. The mixing pump may include a first intake valve configured to control flow of the first fluid, a second intake valve configured to control flow of the second fluid, and an outlet valve configured to control flow of a mixture of the first fluid and the second fluid.