A Pitcher Pump's Handle Is Leaking

Pitcher Pumps

• Today's cast iron pitcher pumps use a design more than 100 years old, but the piston or suction pump concept dates back to the 1500s. Conventional pitcher pumps lift water no farther than 20 feet if operated at sea level, and the practical lift distance drops as altitude increases. Pitcher pumps only appear to lift water. The pump's piston actually creates a partial vacuum above the water in the well pipe. Atmospheric pressure pushing on the water outside the pipe forces water in the pipe higher. As the pump moves more of the air out, the water rises up the pipe.

Plunger Valve

• Pitcher pumps depend on two leather valves to move water and air through the pipe. The plunger valve on the piston seals the gap between the piston and the walls of the pump. The plunger valve, a cup-shaped piece of leather curling up around the bottom of the piston, must create an air-tight seal or the pump can't move water. Pouring water into the pump's top primes the pump by swelling the leather plunger valve shut. As the pump handle lifts, the plunger valve opens and the piston drops. As the handle falls, the valve expands and seals the chamber as the piston rises, creating a vacuum in the pipe.

Flapper Valve

• A leather flapper valve similar to the ball valve in a toilet tank opens as the piston rises, letting air out of the pipe. When the piston falls, the flapper valve seals the pump chamber, preventing the water from falling back. Another stroke of the pump handle brings the water level higher, and eventually the water reaches the pump chamber. Water passes through the flapper valve, which closes and holds the water in the pump. The plunger valve collapses as the piston lowers, but seals on the up-stroke and lifts water to the pump spout, where it pours out. If the operator keeps pumping, water keeps flowing.

Problems

• The gap at the top of the pump stays open to allow priming and let air escape. Some water lifts to the top of the pump, past the pitcher pump's spout, and spills over the top. Where the pump lifts water only a short distance, slowing pump action helps keep water flowing smoothly with less splashing. For longer lifts, operators must use all their strength and speed because the leather valves of pitcher pumps often seal imperfectly. A tiny valve leak can let water drop back faster than the pump lifts it out. Once water flows out the spout, don't stop pumping until you have enough water.