STRAIGHT GLOBE VALVE.
ANGLE GLOBE VALVE.
It is to be noted that all suction pumps receive their water by reason of the pressure of the atmosphere on the surface of the water in the supply tank or well. This atmospheric pressure is about 15 pounds to the square inch, and is sufficient to support a column of water 28 to 33 feet high, 33 feet being the height of a column of water which the atmosphere will support theoretically at about sea level. At greater altitudes the pressure of the atmosphere decreases. Pumps do not work very well when drawing water from a depth over 20 or 22 feet.
Water can be forced to almost any height by pressure of steam on the plunger, and it is taken from deep wells by deep well pumps, which suck the water 20 to 25 feet, and force it the rest of the way by pressure on a plunger.
The amount of water pumped is regulated by a cock or globe valve in the suction pipe.
A Cross-head boiler pump is a pump attached to the cross-head of an engine. The force of the engine piston is transmitted to the plunger of the pump.
The pump portion works exactly the same, whether of the independent or cross-head kind.
The cut represents an independent pump that uses the exhaust steam to heat the water as it is pumped (Marsh pump).
