UFC 3-280-03
23 JULY 2003
As described previously in Subparagraph 2-4.6.3, two types of filter plate and
media washing systems can be used, depending on the specific filter press application.
Filter media water washing systems are described in detail in Subparagraph 2-4.6.3.1.
The frequency can be based on experience and the operator can occasionally check
the media for buildup of residual cake deposits and monitor the cumulative filtrate flow
versus time intervals that occur over the normal filtration cycle.
Acid washing, as described in Subparagraph 2-4.6.3.2, is used primarily for
filter presses that include chemical conditioning with lime. This type of washing is used
to free impregnated solids, such as lime scale buildup, that cause a decrease in the
filter loading rate and an increase of the filtration cycle time.
2-9.6.1.2 Other Cleaning Considerations. In addition to plate and filters, the
hydraulics and pneumatics also need to be clean. Elements that may require periodic
cleaning or replacement include oil and air filters. A summary of periodic cleaning
requirements is presented in Table 2-10. In addition to these items, additional
recommendations for periodic cleaning are provided by manufacturer's specifications.
2-9.6.1.3 Additional Housecleaning Design Considerations. A major component
that requires housecleaning is the sludge cake handling system. For example, the cake
handling system may consist of a conveyor that may bounce and roll and cause sludge
to splatter or cling and accumulate at each transfer point. A cake breaker may also
contribute to these effects. To remedy this situation, the number of transfer points and
distances of drop should be minimized. Other remedies include the use of flexible
chutes and skirt boards. V-shaped or rounded drip trays that are wider than the
conveying system can also be installed beneath the conveyer to collect wash down
water and allow it to drain. Additional housekeeping design considerations for direct
disposal of sludge cake into storage receptacles are also presented in Subparagraph 2-
4.8.2.
2-9.6.2
Lubrication. All moving parts that are subject to wear should be lubricated.
As shown in Table 2-10, several areas of the filter press require normal preventative
maintenance and lubrication. For the specific applications, the press manufacturer's
specifications should be followed. Accessible grease fittings should be provided for
grease-type bearings and those bearings should be provided with relief ports to prevent
buildup of pressure that may damage them or their seals. The oil reservoir should also
be liberally sized, properly vented, and have an overflow opening to prevent overfilling.
In addition to lubricating the filter press equipment, supporting equipment
such as air compressors should be periodically lubricated. For the frequency of main-
tenance and specific lubrication details, the specific manufacturer's details should be
followed.
2-9.6.3 Inspections. In addition to cleaning and lubrication, periodic inspections are
also an important aspect of preventative maintenance. Inspections of the plates and
filter media can find torn filter media at the stay bosses or perimeter of the plates, stay
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