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EXAMPLE: Given a system with 50 psig steam pressure entering the pressure reducing
valve, at a flow of 800 lbs. / hr. of steam and a reduced pressure of 5 psig, find the
smallest sizes of upstream and downstream piping for reasonably quiet steam velocities.
UPSTREAM PIPING: Enter the velocity chart at ‘A’ for 800 lbs. / hr. Move horizontally to
point ‘B’ where the 50 psig diagonal line intersects. Follow up vertically to ‘C’ where an
intersection with a diagonal line falls inside the 4,000 – 6,000 foot / minute velocity
band. Actual velocity at ‘D’ is about 4,000 feet / minute for 2” upstream piping.
DOWNSTREAM PIPING: Enter the velocity chart at ‘A’ for 800 lbs. / hr. Follow
horizontally to point ‘E’ where the 5 psig diagonal line intersects. Move up vertically to
‘F’ where an intersection with a diagonal line falls inside the 4,000 – 6,000 ft/minute
velocity band. Actual velocity at ‘G’ is about 5,500 ft/minute for 3” downstream piping.
7.0 SYSTEM START-UP
7.1 After installation
After the equipment has been completely installed, the following procedures should be
followed.
7.1.1 Inspect all pipe connections to be sure they are correctly and securely connected.
Examine all controls and valves to assure that each is operating freely and properly
lubricated where necessary.
7.1.2 Thoroughly flush vessel and all associated piping until there is no indication of
rust or foreign material. Spray valves and vessel nozzles should be freed of all large
pieces of mil scale or debris.
7.1.3 Ascertain that all instruments and gauges are operating and indicating correctly.
7.2 Initial Start-Up, Cold (No steam available)
7.2.1 Open vent valve completely, exhausting to atmosphere.
7.2.2 Close valve between deaerator and feed pump.
7.2.3 Admit water to deaerator by opening gate valve in make-up water line. Fill
storage section to operating level, as shown on drawing.
7.2.4 Open valve in boiler feed pump suction piping.
7.2.5 Start boiler feed pump and fill boiler with cold water.
7.2.6 Close valve in deaerator make-up water line.
7.2.7 Open scrubber drain valve (in systems equipped with scrubber drain) and drain
scrubber.
7.2.8 Slowly admit steam, when available, to deaerator until normal operating pressure
is obtained. Gradually open the manual valve in the make-up water line, admitting
water at a rate sufficiently slow to maintain a positive steam pressure in the vessel. This
will be evidenced by a continuous escape of steam through the vent. The incoming
water should be manually controlled until it reaches a point sufficient for the water inlet
float valve to maintain a proper level. At this level, manual control will no longer be
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