Chapter hvac engineering Fundamentals: Part 1 Introduction

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Chapter Six
Figure 6.1
Pressure-reducing station.
Figure 6.2
Two-stage pressure-reducing station.
through orifices. If greater pressure reductions are required, it is nec-
essary to use two or more stages, as shown in Fig. 6.2, or to use an
oversized PRV, preferably sized by the manufacturer.
6.2.3
Steam condensate
Condensate is usually returned to the boiler for reuse. In small sys-
tems, this can sometimes be done by gravity. In most systems, pump-
ing is required. The condensate flows by gravity to a collecting tank
from which it is pumped directly to the boiler or to a boiler feed sys-
tem, as described in Chap. 7.
Condensate is basically distilled water. It often includes dissolved
carbon dioxide, making a weak but corrosive carbonic acid. The cor-
Design Procedures: Part 4
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