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CIP Spray Device Design and Application 171
permanent installation in the housing. To spray clean afilter housing requires a
means of keeping the housing essentially empty,which is accomplished by injecting
air into the CIP supply line at the beginning of each phase of the CIP program, and
during periods of recirculation. This air injection approach results in the development
of apocket of air in the housing, and allows the sprays to function as intended.
Experimentation has demonstrated the ability to achieve flow rates of 50 gpm
(190 Lpm) through a filter housing, sufficient to provide a velocity of 5fpm
(1.5 m/sec) through 2-in. piping in the circuit, and upwards of 80 gpm
(300 Lpm), when required, tosimultaneously clean avessel downstream ofthe
filter housing, while accumulating only 1to3gal (3.8–11L)inthe housing.
Aspray-type CIP device as shown in Figure 8isrequired when the filter
housing has nozzle connections on the dome in addition to the spray nozzle
connection. This spray provides the necessary upward vector to assure coverage
in the additional dome nozzles. Alarger hole in the bottom of the machined element
is sized to pass solution not required to clean the housing, and maintain operation at
alow-pressure drop.
Figure 9illustrates adisk distributor type CIP device applicable to any filter
housing free of nozzles in the top dome. The width of the slot between the disc and
the dome is based on flow rate and desired pressure drop through the housing.
Figure 10 is aphoto of an experimental setup in which atest dome fitted with adisk
distributor sized for 50 gpm and 5psi was rotated to discharge horizontally.The full
film of water cascading off the edge of the dome projected several feet as ahollow
tube of water.
The flow rates and operating pressure drop for these sprays are determined
by other elements of the CIP circuit when the filter housing is being cleaned with
piping and adownstream vessel or other equipment. Deliberate incorporation of air
in the CIP stream requires special consideration for handling the CIP return flow.
Rupture disk
Spray tube hole
FIGURE 8 If afilter housing is fitted with nozzles in the top dome area, aspray-type device of short
length and capable of being drilled for awide variety of flow and pressure requirements is used to
direct streams to the multiple nozzles, as when cleaning larger vessels.