UFC 3-280-03
23 JULY 2003
After completing several recirculation cycles, turn the acid pump off. After the
acid pump is turned off, follow with an air blowing cycle, similar to that
described for the normal sludge filtration cycle, to purge acid from the filter
press.
Close all acid feed and recirculation valves.
Open all normal press operation valves.
2-9.5.2 Variable-Volume Press Operation. A typical sequence of operation for a
variable-volume plate and frame filter press is described below. For this sequence of
operation, it is assumed that the variable-volume press system is fully automatic and
equipped with a core blowing system and a fully automatic wash system that allows a
high-pressure water wash on both sides of the filter media. The typical automatic
operation sequence is as follows:
2-9.5.2.1 The closure device is engaged, closing all the chambers of the press.
2-9.5.2.2 The feed pump is started, and the feed is introduced at the initial specified fill
flow rate and pressure.
2-9.5.2.3 After the initial fill cycle is completed, high-pressure water is pumped into the
diaphragms at the minimum specified pressure, causing the diaphragms to expand and
the sludge to dewater to its appropriate dryness.
2-9.5.2.4 After the sludge is dewatered to the appropriate dryness, the feed pump is
stopped and compressed air is blown through the feed pipe and filtrate manifold to
remove any remaining liquids. The water in the diaphragms is also removed, and the
diaphragms are returned to their original position.
2-9.5.2.5 The hydraulic closure device is then depressurized and the filter plates are
separated, allowing the sludge cake to discharge.
2-9.5.2.6 Following sludge cake removal, the filter media are washed on both sides, if
required, and then returned to its original position.
2-9.6
Maintenance Requirements. Maintenance for filter presses includes
measures to keep normal operation on track, such as cleaning and lubrication, and
preventive maintenance, such as periodic inspections and replacement of worn
equipment. A summary of typical parameters and schedule of normal and preventative
maintenance is presented in Table 2-10.
Table 2-10. Typical parameters and schedule for normal and preventive mainte-
nance for filter press equipment.
General
Category
Item
Daily
Weekly
Monthly
Annually
Plate and
Check for cloth holes or cloths out of
X
2-84
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