SPX Cooling Technologies Cooling Tower 600 User Manual

Marley Class 600 Cooling Tower

/ Flexibility of Design /

Class 600 cooling towers are a direct descendent

of the Doubleﬂow

and patented by Marley in 1938. In 1957, Marley’s

development of hanging ﬁll, wide indented louvers, and

stable FRP velocity-recovery fan cylinders enabled the

evolution of that Doubleﬂow tower into the classic Class

600 shape and function that has set the standard for

splash-ﬁll crossﬂow towers for the past half-century.

In addition to form and function, the Class 600

tower has also established a high standard for ease of

maintenance. The open accessibility and cleanability of its

key components—ﬁll, drift eliminators, water distribution

system, and mechanical equipment—takes the drudgery

out of maintenance.

After 50 plus years of industrial market leadership,

the Class 600 continues to be the tower of choice for

users who know the value of thermal performance,

dependability, operational reliability, structural integrity,

and a host of other beneﬁts that have become

synonymous with the Marley name.

crossﬂow tower that was designed

Class 600 cooling towers are available in various cell

sizes, ﬁll air travels, and ﬁll heights. Within each of these

cell plans, several aspects of the basic design can be

varied in order to achieve optimum operating economy.

The choices include variations in ﬁll type and density,

fan type and size, fan cylinder height and shape, drift

eliminator type and density and water distribution method

and operating head.

For each basic cell size, the designer can choose

from a signiﬁcant number of possible component

combinations. Several of these may result in economical

selections capable of the thermal performance

requirements, but only one will optimally satisfy the fan

horsepower, pump head, plan area, and other evaluation

parameters that may have been imposed by the owner’s

speciﬁcations.

Our design engineers review each cooling tower

application to assure that the components selected

will work together as efﬁciently as possible. Computer

optimization assures maximum cooling from a given tower

cell size for each set of design performance conditions.

/ Mechanical Equipment /

Fans

Marley designed and manufactured fans are used on

all Marley crossﬂow towers. The fan selection and fan

speed for a given tower are based on tower cell size,

system losses, and horsepower requirements. Depending

on fan size, blade material is FRP (ﬁber reinforced

polyester), GRE (glass reinforced epoxy), or cast

aluminum alloy. Above 20′-0″ diameter, Marley’s HP7000

hollow core fan with erosion-resistant leading edge is

standard. Large fan hubs are heavy-duty steel plate and

ductile cast iron components, hot dip galvanized after

fabrication. Smaller fan hubs are either epoxy-coated cast

iron or heat-treated aircraft aluminum alloy plate. All fans

are assembled with series 300 stainless steel hardware,

and all materials have been selected for the harsh cooling

tower environment.

Marley fans are applied in accordance with data

from model tests conducted in the wind tunnel at the

SPX Cooling Technologies’ Research and Development

Center. Model fan designs are tested in simulated cooling

towers, and are ﬁne-tuned to maximize efﬁciencies

at actual conditions. The commercially available fans

used by other cooling tower suppliers lack this design

advantage. Consequently, they are often applied at ﬂow

and pressure conditions for which they are ill suited.

Unpredictable lower efﬁciencies result, with proportional

reduction in tower capacity.

Fan Cylinders

Venturi-shaped FRP cylinders combine minimal

entrance losses with close blade tip clearances to

produce optimum fan performance. As cylinder heights

increase, cylinders are progressively ﬂared to promote

recovery of velocity pressure—allowing fans to move

the required amount of air at signiﬁcantly reduced

horsepower.

Unlike those used on other towers, Marley fan

cylinders have exceptionally large entrance diameters

which contribute to the “eased inlet” effect so necessary

to good fan performance. Smaller entrances do not

provide sufﬁcient transition to deter turbulent ﬂow at the

fan. Marley fan cylinders are through-bolted to the fan

deck and supporting framework. The combination of

a large foundation “footprint” and through-bolting has

enabled Marley fan cylinders to withstand wind velocities

in which other fan cylinders have failed.

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