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Knowledge for
the Sulphuric Acid Industry

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Maintenance and
Inspection - Cooling Towers
September 10, 2003
Introduction
The
following inspection checklist provides a general guide of what to look for when
performing a cooling tower inspection. The checklist is general in nature so some of
the points may not apply to your particular installation.
The
results from a thorough cooling tower inspection will enable the plant to properly plan
repairs and maintenance. A properly maintained cooling tower will provide trouble
free and reliable operation.
Maintenance and Inspection Schedule
| Daily |
- Check
operation of cooling water pumps for excessive noise, vibration, etc.
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| Weekly |
- Inspect
trash screen and remove accumulated debris
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| Shutdown |
- Perform a
detailed inspection of system.
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Inspection
Checklist
| Tower Casing |
- Check for leaks, holes, cracks or general deterioration in the
structure.
- Make sure access doors are in good working condition and that
doors shut tightly when tower is in operation.
- Check steel casing for corrosion or scale build-up.
- Check wood casing for signs of decay, soft rot or plywood
delamination.
- Check Fiberglass for evidence of brittleness or cracking.
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| Structure |
- Steel Structures
Inspect steel structures for corrosion, particularly loss of metal.
Spot check the tightness of bolted joints.
Check for corrosion near welded joints on galvanized steel towers.
- Wood Structures
Inspect wood structures for wood decay, cracks, fractures and rot in wood members.
Perform both visually and by tapping with a hammer. A dull, low-pitch sound
indicates softness, while a higher pitch sharp sound indicates sound wood. Probe
soft spots with a sharp object to determine the extent of the damage. Pay particular
attention to the wood around fasteners as well as the bottom of columns.
- Fiberglass or Plastic Structures
Inspect fiberglass or plastic structures lloking for evidence of tearing of
cracking. Spot check the tightness of bolted joints.
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| Fan Deck |
- Check the general condition of the fan deck material looking
for leaks, holes, cracks or general deterioration in the structure.
- Check for the presence of tripping hazards.
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| Cooling Tower Access |
- Stairs
Check for evidence of wood decay or steel corrosion.
Check for loose treads, handrails or stringers.
Check that all hardware is in good condition and tight.
- Ladders
Check the general condition of the material.
Check that all hardware is in good condition and all connections between the tower
and ladder are secure.
- Walkways
Check the general condition of the material.
Check for loose treads or handrails.
Check that all hardware is in good condition and tight.
Particular attention should be paid to any damage or deterioration that may pose a
potential hazard to personnel.
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| Cold Water Basin |
- Check for excessive build-up of sludge or debris. Clean
as required.
- Check condition of sump, sump screen. Clean as required.
- Check the general condition of the basin material.
- Check for any signs of leaks or breakdown of sealing material.
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| Distribution Basins |
- Check the general condition of the material.
- Check for leaks.
- Check that all hardware is in good condition and tight.
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| Piping |
- Examine all supports.
- Check for leaks at all connections.
- Check the general condition of all piping looking for signs of
corrosion or deterioration.
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| Spray Nozzles |
- Check for missing or damage.
- Check for clogged or blocked nozzles.
- Check that all nozzle components are in place and working
properly (i.e. splash plates).
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| Tower Fill |
- Splash Fill
Check the condition of the splash bars. Check for sagging, broken, missing,
heavily-scaled pieces.
Check the support grids.
Check the support members for deterioration and damage.
- Film Fill
Check for build-up of scale, algae or other contaminants on the surface of the
fill.
Check for damaged sheets or sections.
Check the support members for deterioration and damage.
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| Drift Eliminators |
- Check for cleanliness and that all air passages are clear.
- Check the condition of the seals to assure that water can't
bypass the drift eliminators.
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| Louvers |
- Make sure all louvers are in place.
- Check for excessive scale build-up or biological growth.
- Check the condition of the support members.
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| Mechanical Systems |
- Gear Boxes
Check the oil level and condition. Drain off a small sample and check it for
water, metal shavings or sludge. Add or replace the oil as required.
Check for oil leaks and replace seals as required.
Check the backlash and endplay in the gear and record values for future reference.
Check the mounting of the gear box to ensure it is tight and in good condition.
- Couplings and Drive Shafts
Check the coupling alignment.
Check the mid-span bearing (if so equipped) and lubricate are specified in
manufacturer's instructions.
Check the drive shaft for corrosion or damage.
- Belt Drives
Check the condition of the pulleys noting any corrosion or loss of metal.
Check for proper belt tension and alignment.
Check the condition of the belts. If the belt shows signs of wear, gouges or
cracks they should be replaced.
Check the fan shaft bearings for proper lubrication, tightness and that the seals
are in good condition.
Check the support structure for corrosion or damage.
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| Fans |
- Check fan blades for corrosion or erosion.
- Check for excessive build-up of deposits.
- Check the connection between the blades and the hub.
- On fans with variable-pitch blades, carefully measure the
pitch angle of each blade and re-adjust to the manufacturer's recommendations if required.
- Operate the fan and check for excessive vibration that may
indicate an out of balance condition.
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| Fan Stacks |
- Check the condition of the material.
- Check that all hardware is in good condition and tight.
- Check for leaks or holes.
- Measure the fan blades tip clearance all around the stack
using the longest fan blade. Adjust tip clearance as per the manufacturer's
instructions if required.
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The condition of the cooling tower
is important not only from the performance point of view but also from a health point of
view. Cooling towers are ideal breeding grounds for water born bacterial, such as
Legionella bacteria. Cleanliness of all parts of the tower will minimize the chance
of these bacteria growing in the cooling water system
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