Quantcast Impressed Current Cathodic Protection System
 

Click here to make tpub.com your Home Page

Page Title: Impressed Current Cathodic Protection System
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 

or drydocking. The system must be reactivated within
HULL POTENTIAL SETTING OF SHIPS
2 hours after the activity is completed. You must
ENTERING BRACKISH OR FRESH WATER.--
NEVER energize the system if the ship is out of the
As a ship enters a port or bay that is river-fed, the
water (drydocked).
resistivity of the water will change as the salinity
changes. Operation of the ICCP system will be
Before the reference electrode is connected to the
affected by the changing water resistivity. The
controller, check the voltage between the reference
operator will notice the ICCP system operating at
electrode and the steel hull; it should be approximately
higher voltage outputs and lower current outputs. The
0.6 volt dc. The hull will be negative (-) and the
lower current output is caused by the higher
reference electrode will be positive (+). If the voltage
is zero, the reference electrode has an open lead, or the
impedance of the water. A higher voltage output is
lead or electrode is shorted to the hull. When the
required to drive the same current in the higher-
voltage is 0.6 volt or higher, the ship is receiving
resistivity electrolyte. The operator will record this
cathodic protection from an external source, which
condition on the ICCP log. Do not take action to
could be zinc anodes or an electrical leakage.
correct this condition by equipment recalibration
while the ship is in brackish water.
Inspect the controller and power supply wiring to
ensure the unit is properly grounded. Before
CATHODIC PROTECTION LOG.-- Normal
connecting the anode leads to the power supply, check
operating procedures require maintaining a Cathodic
for possible shorts. The voltage developed between a
Protection Log of the ICCP system operation on
disconnected platinum anode and the steel hull will
NAVSEA Form 9633/1 (fig. 11-14, view A, and
range from 1.0 to 2.0 volts dc. This can be read on a
11-14, view B). The readings will be recorded on these
high-impedance voltmeter. The polarity of the anode
logs daily and submitted to NAVSEA monthly, Logs
is positive (+) and the polarity of the hull is negative
submitted to NAVSEA are analyzed to identify those
(-). If this voltage is zero, you could have an open lead
systems that are not operating correctly. After analysis
wire or a shorted anode. When the voltage reads
of the logs is complete, a response is sent to the ship or
between 2.0 to 5.0 volts, it indicates that the anode lead
type command (TYCOM) indicating the operational
is immersed in seawater.
status of the equipment as interpreted from the logs.
HULL POTENTIAL SETTING OF SHIPS IN
This response will recommend corrective actions to be
SEAWATER.-- The ICCP system is designed to
taken, if required.
operate automatically and requires a minimum
Output Check.-- A particularly significant value
amount of maintenance. The operator normally sets
recorded on the log is the output check. The values
the hull potential at -0.85 volt. When the voltage
recorded will range from practically zero to 1.0 volt,
between the hull and the reference electrode is more
representing 100 percent current output. If the values
positive than the voltage set by the operator, the output
of the controller increases. This causes an increase in
range between 0.3 and 0.5 volt, the system is operating
the anode current output from the power supply until
at 30 to 50 percent capacity.
the voltage between the hull and the reference
Power Supply. --The daily current output is
electrode approaches the set voltage. A voltage
recorded for each power supply. Ampere values may
between the hull and the reference electrode that is
vary, depending on the power supply, maximum
negative to the set voltage causes a decrease in
output, and current demand. Two capacities of power
controller output, thereby decreasing the anode
supplies are used, 0 to 150 amperes and 0 to 300
current output.
amperes.
The optimum range of polarization or hull-to-
ICCP MAINTENANCE.-- The ICCP mainte-
reference electrode potential for a ship with an
nance will be performed according to the Planned
ordinary steel hull is from a -0.80 to a -0,90 volt to
Maintenance System (PMS). Take daily meter
the silver/silver chloride reference electrode.
readings on the panel and record them on the log. A
Increased anode current will result in hull potentials
quarterly check must be performed on the shaft
more negative than the optimum amount. Increasing
grounding assembly. Every 24 months the panel
the negative potential does not provide more
meters must be calibrated according to PMS require-
protection. If exceeded, this will result in hydrogen
generation at the hull surface.
ments.
11-14

Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc.