DriSteem Vaporstream Especificações descarregar pdf (Página 71)

P a g e 6 6 • D R I - S T E E M D e s i g n G u i d e

D R I - S T E E M D e s i g n G u i d e • P a g e 6 7

degradation of steam quality, and heat transfer capability. Install

drip legs at all low points and natural drainage points in the

system, such as at the ends of mains and at the bottoms of risers,

and ahead of pressure regulators, control valves, isolation valves,

pipe bends, and expansion joints. On straight horizontal runs

with no natural drainage points, space drip legs at intervals not

exceeding 300' (91.4 m) when the pipe is pitched down in the

direction of the steam flow and at a maximum of 150' (45.7 m)

when the pipe is pitched up, so that condensate flow is opposite

of steam flow. These distances apply to systems where valves are

opened manually to remove air and excess condensate that forms

during warm-up conditions. Reduce these distances by about half

in systems that are warmed up automatically.

• Insulate piping well to avoid unnecessary heat loss.

• Pitch return lines downward in the direction of the condensate

flow at " per 10' (0.4%).

Elevating condensate from a pressurized steam humidifier

In certain installations, it is not possible to drain the humidifier

steam trap by gravity. The condensate must be lifted. Generally,

lifting condensate is not recommended, but it can be done

successfully by observing the following rules:

• Steam pressure. Theoretically, 1 psi (6.9 kPa) of steam pressure

lifts condensate about 2' (0.6 m). But in practice, because of pipe

friction, pressure drop through a steam trap, and back pressure

in a return line, we recommend that you consider the maximum

lift to be 6" per psi (0.2 m per 6.9 kPa) of steam pressure at the

trap. For example, a steam pressure of 5 psi (34.5 kPa) provides a

Pitch " per 10' (0.4%)

Elevated condensate return main

" (DN15) threaded

Inverted bucket steam trap

Check valve

(swing type)

Condensate return ow

Figure 67-1:

Elevating condensate

Maximum lift = 6" per psi

(0.2 m per 6.9 kPa) of steam

pressure at the trap, lifting up

to 5' (1.5 m) maximum

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DriSteem Vaporstream Especificações Página 71