Part 43 (2/2)

The pitch of all pipe should be in the direction of the flow of steam

Wherever a rise is necessary, a drain should be installed Alland each such drop leg and any low points in the systee pu where there is danger of a water pocket

Branch lines should never be taken from the bottom of a main header but where possible should be taken froine supply pipe should have its own separator placed as near the throttle as possible

Such separators should be drained to the drainage system

Check valves are frequently placed in drain pipes to prevent stea any portion of the system that may be shut off

Valves should be so located that they cannot form water pockets when either open or closed Globe valves will for to which they are connected unless set with the steate valves le

Where valves are placed directly on the boiler nozzle, a drain should be provided above theh pressure drains should be trapped to both feed heaters and waste headers Traps and meters should be provided with by-passes Cylinder drains, heater blow-offs and drains, boiler blow-offs and similar lines should be led to waste The ends of cylinder drains should not extend below the surface of water, for on starting up or on closing the throttle valve with the drains open, water may be drawn back into the cylinders

TABLE 64

RADIATION FROM COVERED AND UNCOVERED STEAM PIPES

CALCULATED FOR 160 POUNDS PRESSURE AND 60 DEGREES TEMPERATURE

+---------------------------------------------------------------------+ |+------+---------------------------+----+----+----+-----+-----+-----+| || | | | | | | | || || Pipe | |1/2 |3/4 | 1 |1-1/4|1-1/2| || ||Inches| Thickness of Covering |inch|inch|inch|inch |inch |Bare || |+------+---------------------------+----+----+----+-----+-----+-----+| || |B t u per lineal foot | | | | | | || || | per hour |149 |118 | 99 | 86 | 79 | 597 || || |B t u per square foot | | | | | | || || | per hour |240 |190 |161 | 138 | 127 | 959 || || 2 |B t u per square foot | | | | | | || || | per hour per one degree | | | | | | || || | difference in temperature|770|613|519|445 |410 |3198|| |+------+---------------------------+----+----+----+-----+-----+-----+| || |B t u per lineal foot | | | | | | || || | per hour |247 |193 |160 | 139 | 123 |1085 || || |B t u per square foot | | | | | | || || | per hour |210 |164 |136 | 118 | 104 | 921 || || 4 |B t u per square foot | | | | | | || || | per hour per one degree | | | | | | || || | difference in temperature|677|592|439|381 |335 |2970|| |+------+---------------------------+----+----+----+-----+-----+-----+| || |B t u per lineal foot | | | | | | || || | per hour |352 |269 |221 | 190 | 167 |1555 || || |B t u per square foot | | | | | | || || | per hour |203 |155 |127 | 110 | 96 | 897 || || 6 |B t u per square foot | | | | | | || || | per hour per one degree | | | | | | || || | difference in temperature|655|500|410|355 |310 |289 || |+------+---------------------------+----+----+----+-----+-----+-----+| || |B t u per lineal foot | | | | | | || || | per hour |443 |337 |276 | 235 | 207 |1994 || || |B t u per square foot | | | | | | || || | per hour |196 |149 |122 | 104 | 92 | 883 || || 8 |B t u per square foot | | | | | | || || | per hour per one degree | | | | | | || || | difference in temperature|632|481|394|335 |297 |285 || |+------+---------------------------+----+----+----+-----+-----+-----+| || |B t u per lineal foot | | | | | | || || | per hour |549 |416 |337 | 287 | 250 |2468 || || |B t u per square foot | | | | | | || || | per hour |195 |148 |120 | 102 | 89 | 877 || || 10 |B t u per square foot | | | | | | || || | per hour per one degree | | | | | | || || | difference in temperature|629|477|387|329 |287 |283 || |+------+---------------------------+----+----+----+-----+-----+-----+| +---------------------------------------------------------------------+

Covering--Magnesia, canvas covered

For calculating radiation for pressure and terees, use B t u figures for one degree difference

Radiation from Pipes--The evils of the presence of condensed steahly discussed above and in so from radiation, while it cannot be wholly obviated, can, by proper installation, be greatly reduced

Bare pipe will radiate approximately 3 B t u per hour per square foot of exposed surface per one degree of difference in temperature between the steaure may be reduced to from 03 to 04 B t u for the saives the radiation losses for bare and covered pipes with different thicknesses of

Many experiments have been made as to the relative efficiencies of different kinds of covering Table 65 gives so fro, Jacobus, Brill and others

TABLE 65

APPROXIMATE EFFICIENCIES OF VARIOUS COVERINGS REFERRED TO BARE PIPES +--------------------------------+ |+-------------------+----------+| || Covering |Efficiency|| |+-------------------+----------+| ||Asbestocel | 768 || ||Gast's Air Cell | 744 || ||Asbesto Sponge Felt| 850 || ||Magnesia | 835 || ||Asbestos Navy Brand| 820 || ||Asbesto Sponge Hair| 860 || ||Asbestos Fire Felt | 735 || |+-------------------+----------+| +--------------------------------+

Based on one-inch covering

The following suggestionssurfaces of all pipes, all high pressure steas, heaters and separators, should be covered with non-conductingwill iine and boiler branches, should be covered with 2 inches of 85 per cent carbonate of nesia or the equivalent Other lines may be covered with one inch of the sae surfaces should be covered with blocks, except where such material would be difficult to install, in which case plastic es the covering should be tapered back froe in order that the bolts may be removed

All surfaces should be painted before the covering is applied Canvas is ordinarily placed over the covering, held in place by wrought-iron or brass bands

Expansion and Support of Pipe--It is highly i be so run that there will be no undue strains through the action of expansion Certain points are usually securely anchored and the expansion of the piping at other points taken care of by providing supports along which the piping will slide or by ers Where pipe is supported or anchored, it should be fro structure and not from boilers or prieneral be of any of the nu supports that are available Expansion is taken care of by such a e radius bends where necessary

It was for would actually expand under steam temperatures about one-half the theoretical amount due to the fact that the exterior of the pipe would not reach the full temperature of the steam contained It would appear, however from recent experiments that such actual expansion will in the case of well-covered pipe be very nearly the theoretical a when heated under a working pressure of 190 pounds, the stearees, expanded 8 inches; the theoretical amount of expansion under the conditions would be approximately 9-35/64 inches