Energy/work required to use a bicycle/vacuum pump

The pump dynamics is mathematically described by a First Order Differential Equation. You have to write the differential equation and then solve it before you can calculate the energy expenditure. You also have to know the spring constant and the damping coefficient of the pump to get actual real numbers.

I hope this is helpful

Get a spring scale and observe the average force while moving the handle at the steady rate of your choice through the full stroke against the pressure. Force times distance equals energy (or work if you want to call it so). It's as simple as that.

This method should get you within 10%. Add that inaccuracy amount as part of the safety factor. Note that this gets you the total energy, both the potential energy created in the fluid and the amount lost to friction.

More sophisticated methods of measuring force and moving the piston at a constant velocity will get you more accurate readings as your situation may be require, especially in view of incremental variabilities in both force and velocity.

Note that the force will also vary with the pressure in the line that can be expected to change as you exhaust air from the system. There can also be some load variation with velocity at slower speeds if there is appreciable air leakage back through the valves or piston seals of the pump which will affect the pressure differential across the piston.

Ed Weldon

Remember that there's a difference between pressurizing (pump down-stroke) and evacuating (pump up-stroke with valve reversed).

The maximum pressure differential when pumping out is limited to ~1 bar, but there is no such limit when pressurizing.

To a 1^st approximation, force to move piston is just (pressure difference) x (piston area).

work = force times distance.

force = the difference between the vacuum you desire and atmosphere where you are at plus the friction of your system

distance is the length of the pump pull times the number of cycles you plan to pull.

go for it.....

The last I remember on the engery required was 5 to 7 lbs per sq inch of vaccum.