PRIME MOVERS AND POWER PLANT MACHINERY.
SETTINGS FOR HORIZONTAL RETURN TUBULAR BOILERS.
The quality of brick to be used for boiler settings depends upon
the permanency of the installation and the temperature to be resisted.
Sound, hard-burned red brick can be used for facing, and at other
places where they are protected from the heat. The best quality of
fire brick should be used for linings if high overloads or other ex-
treme conditions of service are likely. Second-grade fire brick can
be used for the better type of fire-box settings where normal condi-
tions prevail. If the boiler is not often subjected to overload most
of the setting can be made of third-grade fire brick, except at the
most exposed places.
Formerly in the California oil fields, when a battery of boilers was
installed, they were bricked up together. Recently, however, many
of the oil companies have bricked up the boilers separately and
often find this method more satisfactory. A 40-horsepower Cali-
fornia-type return tubular boiler, bricked up separately with a 21-
inch wall, requires about 10,000 red brick, 2,000 fire brick, 800
pounds of fire clay, and 8 barrels of lime.
In the California fields, temporary settings are made of common
red brick and adobe by using about 3,500 brick for side and end
walls. As such settings are inefficient and waste fuel, they are going
out of use.
BACK ARCHES FOR HORIZONTAL RETURN TUBULAR BOILERS.
The back arch should be so built that the flue gases do not come
in contact with and overheat that part of the boiler shell above the
water level. The common back-arch construction seen in oil fields,
with the back wall built above the level of the top flues and bricked
over horizontally with fire brick or common brick resting on the
arch bars, often causes trouble if the boiler is overloaded; the sup-
porting arch bars burn out and the back arch falls Furthermore,
every time that work has to be done on the flues the back arch and
end wall have to be torn out. The hinged-back arch, shown in Plate
III, C, at a, consists of special fire brick set in casings hinged at the
lower and outer end. It is being installed with good results in many
of the return tubular boilers in oil-field plants. Those oil com-
panies using this type of back arch claim that it is durable, gives
ready access to the flues, and eliminates the delay, labor, and expense
incident to the tearing down and rebuilding of the old type of back
Many tests have shown that a boiler without insulation will radiate
heat to the surrounding atmosphere at the approximate rate of 3
George, H. C. Surface Machinery and Methods for Oil-Well Pumping. Washington D.C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc12407/. Accessed August 28, 2015.