Miscellaneous Mechanical Components
Makeup valve -
The makeup valve is a valve that introduces fresh water into the
collection basin to maintain the desired collecting basin water
The overflow is a drain that prevents the collecting basin from
The partition is a baffle within a multicell cooling tower that is
used to prevent air and/or water flow between adjacent cells.
The plenum is the internal cooling tower area between the drift
eliminators and the fans.
Speed reducer -
The speed reducer is a right-angle gear box that transmits
power to the fan while reducing the driver speed to that
required for optimal fan performance.
The sump is a depressed portion of the collecting basin from
which cold water is drawn to be returned to the connected
system. The sump usually contains strainer screens, antivortex
devices, and a drain or cleanout connection.
Distribution system -
The distribution system is that portion of a cooling tower that
distributes water over the fill area. It usually consists of one or
more flanged inlets, flow control valves, internal headers,
distribution basins, spray branches, metering orifices, and other
Forced Draft Cooling Towers
Forced draft cooling towers are very similar to induced draft cooling towers. The primary
difference is that the air is blown in at the bottom of the tower and exits at the top. Forced draft
cooling towers are the forerunner to induced draft cooling towers. Water distribution problems
and recirculation difficulties discourage the use of forced draft cooling towers.
Natural Convection Cooling Towers
Natural convection cooling towers, illustrated in Figure 12, use the principle of convective flow
to provide air circulation. As the air inside the tower is heated, it rises through the tower. This
process draws more air in, creating a natural air flow to provide cooling of the water. The basin
at the bottom of the tower is open to the atmosphere. The cooler, more dense air outside the