Engineering Bulletin No 1: Boiler and Furnace Testing | Page 8

through cracks in the
brickwork, leaks around the frames and edges of cleaning doors, and
holes around the blow-off pipes. There are also other places where such
air can leak in.
Take a torch or candle and go over the entire surface of your boiler
setting--front, back, sides, and top. Where the flame of the torch is
drawn inward there is an air leak. Plaster up all air leaks and repair the
brickwork around door frames where necessary. You should go over
your boiler for air leaks once a month.

In regard to best methods of firing soft coal, see Technical Paper No.
80 of the Bureau of Mines, which may be obtained from your State
Fuel Administrator.
Dirty heating surfaces cause low efficiency because they prevent the
heat in the hot gases from getting through into the water. Therefore,
keep the shell and tubes free of soot on one side and scale on the other.
Soot may be removed by the daily use of blowers, scrapers, and
cleaners. The problem of scale and pure feed water is a big one and
should be taken up with proper authorities on the subject.
There are many things that may be done to increase the efficiency of
the boiler and to save coal. For convenience a number of these points
are grouped in the following list:
WHAT TO DO. | WHY. | 1. Close up all leaks in the boiler | To prevent
waste of heat due to setting. | excess air admitted. | 2. Keep shell and
tubes free from | To allow the heat to pass easily soot and scale. | into
the water. | 3. Use grates suited to the fuel | To prevent loss of unburnt
coal to be burned. | through air spaces. | 4. Fire often, and little at a | To
obtain uniform conditions and time. | better combustion. | 5. Cover all
thin spots and keep | To prevent burning holes in bed fire bed level. |
and admitting excess air. | 6. Do not allow clinkers to form | Because
they reduce the effective on side or bridge walls. | area of the grate. | 7.
Keep the ash pit free from ashes | To prevent warping and burning out
and hot clinkers. | of the grates. | 8. Do not stir the fire except when |
Because stirring causes clinker necessary. | and is likely to waste coal. |
9. Use damper and not ash-pit doors | Because less excess air is to
control draft. | admitted by so doing. | 10. See that steam pipes and
valves | Because steam leaks waste heat are tight. | and therefore coal. |
11. Keep blow-off valves tight. | Because leaks of hot water waste |
coal. | 12. Cover steam pipes and the tops | To prevent radiation and
loss of of boilers. | heat.
Make a boiler test under the conditions of operation as they now exist
in your plant. Then make all possible improvements as suggested in
this bulletin, make another test afterwards and note the increase in the
equivalent evaporation per pound of coal used.

Remember that the firing line in the boiler room can be just as patriotic
and helpful as the firing line at the front.
Table of factors of evaporation.
===================================================
========================= Feed | Steam pressure in pounds per
square inch, gauge.
temperature,|--------------------------------------------------------------- °F. |
30 | 50 | 70 | 80 | 90 | 100 | 110 | 120
------------+-------+-------+-------+-------+-------+-------+-------+------- 32
| 1.2073| 1.2144| 1.2195| 1.2216| 1.2234| 1.2251| 1.2266| 1.2279 35 |
1.2042| 1.2113| 1.2164| 1.2184| 1.2203| 1.2219| 1.2235| 1.2248 38 |
1.2011| 1.2082| 1.2133| 1.2153| 1.2172| 1.2188| 1.2204| 1.2217 41 |
1.1980| 1.2051| 1.2102| 1.2122| 1.2141| 1.2157| 1.2173| 1.2186 44 |
1.1949| 1.2020| 1.2071| 1.2091| 1.2110| 1.2126| 1.2142| 1.2155 47 |
1.1918| 1.1989| 1.2040| 1.2060| 1.2079| 1.2095| 1.2111| 1.2124 50 |
1.1887| 1.1958| 1.2009| 1.2029| 1.2048| 1.2064| 1.2080| 1.2093 53 |
1.1856| 1.1927| 1.1978| 1.1998| 1.2017| 1.2033| 1.2049| 1.2062 56 |
1.1825| 1.1896| 1.1947| 1.1967| 1.1986| 1.2002| 1.2018| 1.2031 59 |
1.1794| 1.1865| 1.1916| 1.1937| 1.1955| 1.1972| 1.1987| 1.2000 62 |
1.1763| 1.1835| 1.1885| 1.1906| 1.1924| 1.1941| 1.1956| 1.1970 65 |
1.1733| 1.1804| 1.1854| 1.1875| 1.1893| 1.1910| 1.1925| 1.1939 68 |
1.1702| 1.1773| 1.1823| 1.1844| 1.1862| 1.1879| 1.1894| 1.1908 71 |
1.1671| 1.1742| 1.1792| 1.1813| 1.1832| 1.1848| 1.1864| 1.1877 74 |
1.1640| 1.1711| 1.1762| 1.1782| 1.1801| 1.1817| 1.1833| 1.1846 77 |
1.1609| 1.1680| 1.1731| 1.1751| 1.1770| 1.1786| 1.1802| 1.1815 80 |
1.1578| 1.1650| 1.1700| 1.1721| 1.1739| 1.1756| 1.1771| 1.1785 83 |
1.1548| 1.1619| 1.1669| 1.1690| 1.1708| 1.1725| 1.1740| 1.1754 86 |
1.1518| 1.1588| 1.1638| 1.1659| 1.1678| 1.1694| 1.1710| 1.1723 89 |
1.1486| 1.1557| 1.1608| 1.1628| 1.1647| 1.1663| 1.1679| 1.1692 92 |
1.1455| 1.1526| 1.1577| 1.1597| 1.1616| 1.1632| 1.1648| 1.1661 95 |
1.1424| 1.1495| 1.1546| 1.1566| 1.1585| 1.1602| 1.1617|