Plumbing Experiences.—No. 2.
The plumber thus being confronted by the problem of no water in the upper stories of the building, resorts to storage on a small scale and recommends that a tank be placed in the upper part of the building, sufficient in size to meet the daily demand.
The experience thus far proves that during the day the bath tub, water closets and wash basins get no water, but after the day’s draught throughout the city is somewhat diminished, water will flow until the morning hour returns and cessation of flow is again inaugurated. This feature of water distribution is common to all large cities after a number of years experience. To plumbers of thought they can very readily determine by observation how much loss of head is due to the daily flow of water for distribution in the city in which they practice their profession. The tank method is a safe one to provide for creating head during the day; in fact it is the only method to adopt in absence of pressure from city mains during the day. The tank should always be large enough to meet every want incident to the requirements of a hot and cold water supply. The lack of tank room is an oversight, and the result is that complications in the way of connections and check valves are obliged to be made by plumbers in order to economize the tank supply depending partially upon the street service for a water supply in the lower stories. One branch pipe should be maintained for a direct drinking water supply independent of the tank water.
A daily diminishing pressure soon makes it impracticable to depend upon the increased night pre^ure to fill the tank in the upper stories of buildings on elevated planes and recourse must be had to pumps. The plumber of New York city, particularly above any other phase of his practice, has had more to do with pumps than plumbers of other cities.
It is pretty well recognized among plumbers that a separate rising main pipe to the tank is the best plan. Yet it is to be admitted that a little more care and judgment can be used regarding the method of suction. Rather than connecting the same direct to the service pipe, the best plumbing practice is exhibited in the construction of a watertight suction tank made of boiler iron of liberal capacity in cubic feet, to which the service main is attached and from which the suction is taken and connected direct to pump, care being taken that the suction of the pump does not exhaust the contents of the tank. In other words that the inflow of the supply to the tank more than equals the ability of the suction to create a vacuum in the tank. Again the advantage of a. water-tight suction tank is found that if the pressure from the street main should raise the water through the pump valves and into the rising main, then there is less lift for the pump—equal to the pressure the water may be raised in the rising main.