This scale drawing for a solar-powered fluidyne shallow well pump is an attempt to design a well pump capable of providing water for people and vinyards in remote arid areas in and around Mendoza Province in Argentina and, if successful, may become a basis for water supply in other areas.
This fluidyne engine has a 100 mm bore, and both the well pipe and the U-shaped pipe have a 50 mm inside diameter. The check valves are of the 'flapper' type that open upward in response to pressure from below, are closed by gravity, and sealed by the weight of the water above.
The energy source is a parabolic trough concentrator which delivers air heated to 725°F/384°C into the space between an insulating jacket and the fluidyne engine's hot head.
The fluidyne engine converts the heat energy to mechanical energy in the form of alternating high and low pressures in the descending U-shaped pipe, which joins the well pipe at a T-fitting. Immediately above and below the T-fitting are check valves which permit water to flow only upward.
During the low-pressure portion of the cycle, water is drawn upward from the bottom of the well through the lower half of the well pipe, through the lower check valve, and into the U-shaped pipe.
Then, during the high-pressure portion of the cycle, the water is pushed back out of the U-shaped pipe into the well pipe, through the upper check valve, through the upper portion of the well pipe, and the water already at the top of the well pipe is discharged.
The two check valves and the T-fitting are located near the middle of the well pipe to avoid drawing sand into the check valves during the low-pressure portion of the cycle, and to ensure that there is sufficient water above the check valves to produce enough back pressure to seal them securely.
The loop in the U-shaped pipe is intended to prevent air from being drawn into the fluidyne engine if/when the well pipe is not filled with water. The loop should be long enough that if air is drawn from the well pipe, it will not pass the bottom of the loop.
Note: This design was quickly obsoleted by a single-piston inline version.
Team Argentina - Mendoza
Just to keep the record straight, the real work on this project is being done in Argentina by a group that has already designed and built a conventional Stirling engine. You can learn more about their work by visiting their web site.
(After sending the design, I never received any feedback so have no way of knowing if they actually built/installed any fluidyne pumps.)