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Pumps and Hydraulics, Part 1 (of 2)

Chapter 59: DOMESTIC ELECTRIC PUMPS.
By N. Hawkins
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About This Book

A practical manual that begins with a historical survey and the principles of hydro-mechanics, hydrostatics and pneumatics, then examines flow under pressure, gravity, and friction. It surveys water-pressure machines, water wheels and turbine types, and hydraulic apparatus including jacks, presses, accumulators and rams. The work classifies pumps and provides detailed, illustrated treatments of hand, belted, electric, steam (single, duplex and compound), centrifugal, rotary, jet and injector types, plus compressors, pulsometers and fire and mining applications. Practical guidance on valves, management, calculations, rules, tables and a glossary round out the text.

DOMESTIC ELECTRIC PUMPS.

Fig. 238.

Fig. 239.

In many places the pressure on the mains is insufficient to raise the water to the upper floors or through improperly designed systems of piping the pressure may be so diminished as to make the flow extremely weak or the difficulty in securing proper water supply may be due to inconvenient location with reference to water mains. The automatic electric house tank pumping plant has been designed and perfected to meet these conditions; the electric plant is connected to some power or lighting circuit and provided with an automatic attachment requiring no more care than can be given by any casual attendant. Such an installation avoids the smoke, ashes, dust and objectionable odors that accompany steam or gas plants.

The accompanying diagram shows the general arrangement of the automatic electric house system used with a tank in the upper part of the building and the pump in the basement or cellar. The operation is as follows:

When water is being delivered to the tank, the float rises until the upper knob makes forcible contact with the switch lever, opening the switch and stopping the pump. When water is withdrawn from the tank, the float falls until the lower knob makes contact with the switch lever, which again closes the switch and starts the pump. The supply of water is thus maintained within the tank without the aid of an attendant. The accompanying illustration, Fig. 238, shows a Worthington house tank pump of 500 gallons per hour capacity belted to a General Electric direct current motor, the pump and motor being mounted on the same base.

Table of Capacity.

Diameter
of Plungers		 Length
of Stroke		 Revolutions
per Minute		 Gallons
per Minute		 Maximum
Water
Pressure
in Lbs.		 Gallons
per Hour		 Feet 1 H.P.
Will Pump
Against		 Feet 2 H.P.
Will Pump
Against
2 4 45 9.8 150 500 175 300
23⁄4 4 45 18.5 75 1,000 80 175
3 4 45 21.8 60 1,200 70 140
33⁄4 4 45 34.4 40 1,800 50 100

The above useful table is inserted to show the capacities, revolutions, size of plungers, etc., in these electrically driven pumps, the automatic feature of which is truly admirable.

It must be remembered that the number of combinations between small electric motors and proportionate pumps for water, gas, air, etc., afford an endless field for the exercise of engineering skill.