As the water is heated it becomes lighter, rises to the top of the boiler, and passes along the flow pipe.
From this point the " return " pipe drops, usually at the same rate as the flow pipe rises; and in due course the water reaches its starting point, the boiler, and is again heated and again circulated through the system.
4) acts on precisely the same principle, but in place of two pipes being placed in adjacent positions one large main makes a complete circuit of the area to be warmed, starting from and returning to the boiler, and from this main flow and return branches are taken and connected with radiators and other heating appliances.
5) a rising main is taken directly from the boiler to the topmost floor of the building, and from this branches are dropped to the lower floors, and connected by means of smaller branches to radiators or coils.
This steam condensing adds to the water in the pipe and naturally causes an overflow, which is led back to the boiler and re-used.
In districts where the water is hard, this arrangement considerably lengthens the life of the boiler, as Alternative method with separate return pipe ?
Boiler Tap to, empty +G the same water is used over and over again, and no fresh deposit of fur occurs.
6) has many advantages, for it is safe, the boiler is small High and is easily managed, the temperature is well under control and may be regulated to suit the changing weather, and the small pipes present a neat appearance in a room.
The boiler consists of similar pipe coiled up to form a fire-box, inside which the furnace is lighted.
For large public buildings, factories, &c., heating by steam is generally adopted on account of the rapidity with which heat is available, and the great distance from the boiler at which warming is effected.
In the low pressure two pipe system the flow pipe is carried to a sufficient height directly above the boiler to allow of its gradual fall to a little beyond the most distant point at which connexion is to be made with the return pipe, which thence slopes towards the boiler.
The one-pipe system is similar in principle, the pipe rising to its greatest height above the boiler and being then carried around as a single pipe falling all the while.
In small houses all requirements may be satisfied with a boiler heated by the kitchen fire.
For large buildings where large quantities of hot water are used an independent boiler of suitable size should be installed.
Every installation is made up of a boiler or other water heater, a tank or cylinder to contain the water when heated, and a cistern of cold water, the supply from which to the system is regulated automatically by a ball valve.
The flow pipe starts from the top of the boiler and is connected near the top of the cylinder, the return pipe joining the lower portions of the cylinder and boiler.
The supply from the cold water cistern enters the bottom of the cylinder, and thence travels by way of the return pipe to the boiler, where it is heated, and back through the flow pipe to the cylinder, which is thus soon filled with hot water.
12 the cylinder is placed in proximity to the boiler; this is the usual and most effective method, but it may be placed some distance away if desired.
All draw off services are taken off from the flow pipe which connects the boiler with the tank.
A suitable proportion between the size of the tank or cylinder and that of the boiler is 8 or io to 1.
In the choice of a boiler of this description it should be remembered that rapid heating, economical combustion of fuel, and facilities for cleaning, are requisites, the absence of any of which considerably lowers the efficiency of the apparatus.
The lime deposit or " fur " is a poor conductor of heat, and it is therefore most detrimental to the efficiency of the system to allow the interior of the boiler or any other portion to become furred up. Further, if not removed, the fur will in a short time bring about a fracture in the boiler.
The boiler evaporated 184 cub.
The second group consists of experiments made on a boiler belonging to the Great Eastern Railway Company.
7 he torque exerted on the driving-axle by the steam engine just at starting may be that due to the full boiler pressure acting in the cylinders, but usually the weight on the coupled wheels is hardly sufficient to enable advantage to be taken of the full boiler pressure, and it has to be throttled down by the regulator to prevent slipping.
In one company dinner was ready, and the soldiers were gazing eagerly at the steaming boiler, waiting till the sample, which a quartermaster sergeant was carrying in a wooden bowl to an officer who sat on a log before his shelter, had been tasted.