Explain the action of the ordinary suction pump.

When the pump boxes are raised in the barrel of the pump, they exhaust the air to a certain extent, leaving behind a partial vacuum. When this happens there is nothing to counteract the atmospheric pressure, which is exerted on the surface of the water in the well. This pressure at once forces water up into the pump, from which it passes out through a spout.

What are the pumps most commonly in use?

The suction pump, the lift pump, and the force pump.

Theoretically, how high can water be drawn by suction?

A trifle over thirty-three feet.

Practically, how high can water be drawn by suction?

Not much over twenty-eight feet, and very often circumstances will not allow it to be drawn much over twenty-five feet.

What causes make this difference in the height to which water can be raised?

At the sea level, atmospheric pressure is greater than at the top of a mountain. Then too, the pump boxes are not so perfect as to leave a perfect vacuum, and atmospheric pressure is counterbalanced to some extent by the friction of the water on the pipe, by bends in the pipe, and by long horizontal runs.

Can water be drawn from as great a depth on a high elevation as on a lower one, or not, and why?

It cannot be drawn so great a distance, for atmospheric pressure is less on the higher elevation.

Explain the action of the lift-force pump.

In this pump there is a check valve opening upward in the delivery pipe. There is also a valve in the piston. As the piston travels up, a partial vacuum is created, and water enters the pump as in the case of the suction pump described above. When the piston travels down, it compresses the water, thereby closing the lower valve and forcing the water through and above the piston. As the piston now travels up, the weight of the water closes the piston valve and the water is lifted. The lifting of the water forces open the check valve in the discharge pipe which has been kept closed by the weight of the water standing in this pipe. The water which has been lifted, is now forced through this check valve into the discharge pipe. As soon as the force which keeps open this valve is withdrawn, the weight of water in the discharge pipe keeps the valve closed until water is again raised on the next stroke.

Explain the action of the force pump.

In the force pump as in the lift-force pump, there is a check valve in the delivery pipe, but the piston of the force pump is solid. Water enters the pump by means of suction. When the piston travels down, it closes the lower valve and compresses the water in the pump, forcing it into the discharge pipe, and forcing the check valve open. When this pressure is withdrawn, the weight of the water closes the check valve until compression again forces more water into the discharge pipe.

Name different ways in which a water supply may be procured where there is no city pressure.

By means of gravitation or by means of syphonage from a spring or other supply above the point of delivery; by means of the hydraulic ram, when the source of supply is lower than the point of delivery, and a fall can be secured from the source of supply to the ram; and by means of the pump worked either by hand, by windmill, or by engine.