EXHAUST STEAM HEATING.
Fig. 144.
Taking the experiments as a whole, it will be seen that in a flue 6 inches in diameter, the maximum speed of current which can be obtained with economy is about 200 feet per minute; and this was realized with a gas consumption of 1 cubic foot per hour—1 cubic foot of gas removing 2,460 cubic feet of air.
It should, however, not be required of any system of heating to more than aid in ventilation. It is the architect’s or builder’s performance to so arrange lower and upper openings to drive out the bad air.
Heating by Exhaust Steam.
There are two methods of warming by steam heat—one with live steam direct from the boiler, and the other with exhaust steam. These two are frequently carried out in combination, and in fact generally so where exhaust steam is used at all for warming.
In nearly all manufacturing establishments, office buildings, etc., the exhaust steam produced will very nearly, if not quite supply sufficient exhaust steam to furnish all the heat required for heating the building during average weather, although in extremely cold weather, a certain amount of live steam might be necessary to use in connection with the exhaust to supply the required amount of heat.
A simple and convenient device operating upon the suction principle has been found to be most efficient. By this the exhaust steam is drawn almost instantly through the most extensive piping; preventing condensation, freezing and hammering, after which it is condensed and purified, and fed back into the boiler by the means of a reciprocating pump.
It is claimed that a given quantity of exhaust steam can be circulated by this vacuum system and uniformly distributed through double the amount of heating pipes than could be accomplished by the same quantity of exhaust steam when forced into the heating system by pressure.