water pump engineering

[Charles B]

A drill pump uses rubber flanges to create suction in order to draw water into it, through a garden hose and then expel it. It is a simple design but the friction caused by it being airtight makes it extremely hard to turn. If I used a smaller diameter hose, would it need less suction to draw and expel the water?

[LucidDreamer]

Sounds like a trick question on a physics exam, but ill give it a shot. My guess is no; reducing the diameter of the hose will not reduce the amount of needed suction. By reducing the diameter of the hose you are suctioning the same amount of water as a larger diameter hose but at a faster rate. The increased speed would create more friction and might actually make the wheel harder to turn. To make it easier to turn you could increase the size of the wheel on the pump.

[rbp6]

Lucid I'd have to disagree with you on one point. It would seem to me that you'd actually be sucking much less water up per second than a larger hose. Compare drinking from a straw to sucking from a hose. I'm sure that the hose would give you more per second and also require more power to maintain.

 

Though you're right, increasing the size of the wheel is probably the easiest way to fix his problem. Other than just making everything motorized.

[YT2095]

the larger the bore on your hoses (inlet and outlet) the easier it will be on your pump.

constriction at either end (makes no difference) will build pressure, and that pressure will be directly rellated to the strain on your motor, take it to exterems to see what I mean, fill the line with water and block the inlet or outlet, soon your pump and motor will protest!

the larger the bore, the less work is wasted in pressure, you`ll just get a clean throughput