on 3/1/2008 10:57 AM Tom J said the following:
The differences in hand pump depth lift depends upon whether the pumping mechanism (the pipe, rod, and piston) is lifting the water or sucking it up. If below the surface, yes, the water can be lifted to many heights, because it is lifting (pushing up) the water, rather than sucking it up. If the piston is at ground level, then the piston has to first evacuate the air from the pipe which causes a vacuum in the pipe. It doesn't matter whether the pump is hand powered or motor powered. The vacuum created by evacuating the air is replaced by the water that the ambient barometric pressure pushes down on the surface of the water. When in the Navy, my battle station was damage control. We used a portable water pump called a Handy Billy. It had a gas engine that drew water from a long hose that was dropped into the flooded area. It's maximum lift was listed as 30 feet. If the water level in the flooded area was more than 30' from the pump, then the Handy Billy could be moved to a lower deck that was within the 30' limit, if possible, and its discharge could be hosed to a higher level and over the side, or through discharge ports in the side. The pump then becomes a lifting and pushing pump The most use of the discharge port that was in our shop was to wrap a piece of wire around our AM radio antenna and hang the other end out the port, so we could pick up a signal. :-) The Handy Billy could also be used to fight fires when the ship's power was lost, drawing its water from the sea (as long as the sea level was not more than 30' below the pump), and using the discharge hose as a fire hose.