The radiation used in direct steam heating is made up of cast iron radiators of various forms, pipe radiators and circulation coils.

Cast Iron Radiators

The general form of cast iron sectional radiators has been shown in Fig. 2. They are made up of sections, the number depending upon the amount of heating surface required. Fig. 37 shows an intermediate section of a radiator of this type. It is simply a loop with inlet and outlet at the bottom. The end sections are the same, except they have legs as shown in Fig. 38. These sections are connected at the bottom by special nipples so that steam entering at the end fills the bottom of the radiator, and being lighter than the air rises through the loops and forces the air downward and toward the farther end, where it is discharged through an air-valve placed about midway of the last section. There are many different designs varying in height and width, to suit all conditions. The wall pattern shown in Fig. 4 is very convenient when it is desired to place the radiator above the floor, as in bath rooms, etc.; it is also a convenient form to place under the windows of halls and churches to counteract the effect of cold down drafts. It is adapted to nearly every place where the ordinary direct radiator can be used and may be connected up in different ways to meet the various requirements.