Such a pump, with the “pit-man” extending from the pump upwards into the tower, is shown in Fig. [465]. This figure is introduced to show the tank connections with a regulator on the base of a four-post tower. The float in the water tank throws the mill in or out of gear according as the water rises or falls in the tank.
When the tank is filled with water it pulls the mill out of gear and stops the pump; as a result there can be no overflow or waste. The tank is thus not allowed to become empty and permit its drying apart, inducing leakage. But through the medium of the float in the tank, when the water has been lowered but a few inches, the mill is again put in gear and the tank refilled to the desired height, at which the float is set.
Note.—These have long been erroneously termed windmill pumps dating to the time when wind furnished the power for driving the grist mills used in grinding grain, etc. More properly they may now be named windmotors or airmotors.
The syphon pump here illustrated, Fig. [464], is used to force water from shallow wells to elevations. The cylinder or barrel is situated within the standard and very convenient for inspection. It has an air chamber which is detachable.
Fig. 464.
The subject of tanks and cisterns is one almost vital to the successful operations of ordinary windmills, owing to the irregularity of the power to be utilized by the use of aermotors.
In another part of this work this important subject will be further explained and illustrated.
One of the most valuable special features of this windmill is its governor. It is so contrived that it insures immunity of the mill from injuries in destructive storms. It consists of a steel coiled spring of great resiliency, located at the base of the vane frame. Its strength is of such a character as to hold the wheel in the teeth of the wind under all ordinary conditions but is sure to yield under greater pressure.