SPX Cooling Technologies 800 User Manual
>ViÊNÊ>ÊÀÞÊ}ÊNÊ>ÀiÞ
}Ê/iV}iÃ
Marley Class 800 Mechanical Draft Cooling Tower
/
/
User Manual 95-1356A
Warning
▲ Caution
▲ Note
Notice
The following defined terms are used throughout this manual to bring
attention to the presence of hazards of various risk levels, or to important information concerning the life of the product.
Indicates presence of a hazard which can cause severe personal
injury, death or substantial property damage if ignored.
Indicates presence of a hazard which will or can cause personal injury
or property damage if ignored.
Indicates special instructions on installation, operation or maintenance
which are important but not related to personal injury hazards.
These instructions assist in obtaining efficient, long life from Marley
cooling equipment. Direct questions concerning cooling tower operation and maintenance to your Marley sales office or representative.
Always include your tower serial number when writing for information or ordering parts. Look for this number on the nameplate near
the access.
2
Contents
General ................................................................................................... 4
Before Start-up ....................................................................................... 5
Initial Starting Procedure ........................................................................ 7
Routine Starting Procedure .................................................................... 8
Operation ................................................................................................ 9
Freezing Weather Operation ................................................................. 11
Temperature Control and Energy Management ................................... 13
Maintenance ......................................................................................... 15
Cleaning ............................................................................................... 17
Water Treatment ................................................................................... 18
Seasonal Shutdown Instructions .......................................................... 20
Spare Parts and Accessories ............................................................... 21
Troubleshooting .................................................................................... 22
Safety ................................................................................................... 24
Inspection and Maintenance Schedule ................................................ 25
Inspection Checklist ............................................................................. 26
3
General
A cooling tower, like any heat exchanger, exchanges all heat imposed
upon it from one fluid to another fluid. For a cooling tower, heat from the
water is put into the air. The plant process replenishes the heat to the
water, typically at another heat exchanger such as a condenser. A cooling
tower differs from many heat exchangers in that heat is transferred in two
forms—sensible and latent heat. As heat is transferred from the water, the
air temperature increases (sensible) and the air’s water content, or humidity, also increases (latent). As the heat load, inlet air wet-bulb temperature,
or airflow on a cooling tower changes, the cooling tower will respond by
finding a new equilibrium with the process. The cooling tower will still dissipate all the heat from the process, but at new water temperatures.
The cooling tower cold water temperature is the supply water temperature
to the condenser, and changes in the cold water temperature usually affect
efficiency of the plant output. Although the reduced cold water temperatures that result from maximum fan power utilization are usually beneficial
to plant output, the amount of fan power affects the cost of running the
cooling tower. As these variables interact on a cooling tower, the operator
must find the proper trade-off between these opposing forces.
These instructions will assist in obtaining efficient, long life from Marley
cooling equipment. Direct questions concerning tower operation and
maintenance to your Marley sales office or representative. Always include
your tower serial number when writing for information or ordering parts.
Look for this number on the nameplate near the tower access.
4
▲ Caution
Before Start-up
Safety
Temporary safety barricades should be placed around any exposed
openings in the operating (or nonoperating) tower, safety harnesses
should be worn by personnel where appropriate, and other safety
precautions should be taken in compliance with OSHA regulations
and standards.
Cleaning
Clean any nozzles that are clogged. Remove any sediment from the cold
water basin, sump and screens. Use a water hose to flush cold water
basins.
If you are restarting or recommissioning a previously used tower, see
Warning note on page 17.
Inspection
It is imperative that all operating assemblies be inspected before they are
placed in operation. The following is a list of components to be checked
before starting the tower:
• Check drive shaft alignment. Realign if necessary. See Marley Drive
Shaft Service Manual.
• Check tightness of bolts that attach mechanical equipment support to
the tower structure. Check tightness of bolts in fan cylinder joints and
fan cylinder anchorage.
• Check concrete structural surfaces for spalling and cracks. Repair as
necessary.
• Check tightness of the following bolted joints in the fan and drive assemblies:
– Fan hub clamp bolts. See Marley Fan Service Manual for correct
torque setting.
– Fan hub cover bolts, where applicable.
– Geareducer® and motor mounting bolts.
– Drive shaft coupling and guard bolts.
• Check Geareducer oil for sludge or water by draining off and testing a
sample as outlined in the Marley Geareducer Service Manual. Check
Geareducer oil level at “oil level” mark on the side of the case. Add oil
as required. The oil level placard must be adjusted so that its “full” mark
is at the same elevation as the “full” mark on the side of the Geareducer
case. Check oil lines to be sure there are no leaks and all joints are tight.
➠
5
Before Start-up
See Geareducer Service Manual for oil filling procedure and list of
recommended lubricants.
• Rotate fan by hand to be sure of free rotation and ample tip clearance.
See Marley Fan Service Manual.
• Check motor insulation with a “Megger.” See maintenance section of
Marley Electric Motor Service Manual.
• Lubricate the motor according to motor manufacturer’s instructions.
• Test run each fan separately for a short time. Check for excessive vibration or unusual noise. If either is present, see Troubleshooting on pages
22 and 23 of this manual. Fan must rotate clockwise when viewed from
above. Recheck Geareducer oil level.
• Check functioning of make-up water supply.
• Make sure the blowdown or bleed-off will carry the proper amount of
water. (See Blowdown on page 18.)
Operate Water System
Complete steps 1 thru 4 under Initial Starting Procedure on page 7. Circu-
late water over the tower continuously for several days before starting the
mechanical equipment and putting the tower into continuous operation.
▲ Caution
Do not circulate water over the tower in freezing weather without a
heat load. (See Caution note on page 8.)
6
Initial Starting Procedure
1— Fill the cold water basin and circulating water system to a level 1/2”
(13 mm) below the overflow.
2— Bypass valve should be closed unless start-up is in cold weather. (See
Routine Starting Procedure on page 8.)
3— Prime and start the circulating water pumps one at a time. Increase the
flow of circulating water gradually to design water rate to avoid surges
or water hammer which could damage the distribution piping.
4— When flow has stabilized at or near the design rate, adjust water
make-up to maintain the level that the water has pumped down to
in the cold water basin. (See Cold Water Collection Basin on page
10.) This should coincide reasonably with the recommended operating
water level indicated on the Marley project drawings.
5— Start the fan(s). After 30 minutes operating time, to permit Geareducer
oil to come up to operating temperature, check motor load with watt
meter, or take operating volt and ampere readings and calculate motor
horsepower. Refer to Marley Fan Service Manual for instructions.
▲ Caution
If it is necessary to adjust fan pitch to pull correct contract horsepower, measure results when circulating design water rate at design
hot water temperature. Horsepower will change with air density. Lock
out all electrical service before entering fan area.
7
▲ Caution
Routine Starting Procedure
After periods of routine shutdown, the following restarting procedure
should be followed:
• Start the circulating water pump(s). Increase the flow of circulating water
gradually to design water rate to avoid surges or water hammer which
could damage the distribution piping.
Circulating cold water over a tower in freezing weather will cause ice
to form, which may cause damage to the fill system. Water should be
bypassed directly to the cold water basin until the heat load causes
its temperature to rise above 70°F (21°C), at which time it may be
directed over the tower. Also, towers must not be operated with
reduced water rate and/or no heat load during freezing weather. If
a bypass is used, do not modulate.
• Start the fan(s). On multi-cell towers, only as many fans should be started
as are needed to produce the desired cold water temperature. If the
tower is equipped with two-speed motors, fans may be progressively
started at half speed, increasing to full speed as necessary to maintain
the desired cold water temperature. (See Temperature Control and
Energy Management on pages 13 and 14.)
8
Operation
Tower Performance
The following is intended to serve as a guideline for the operation of this
counterflow mechanical draft cooling tower. The owner may use this information to develop preliminary operating procedures. As operational experience with the system accumulates, more definitive responses to specific
conditions will be developed by the owner’s operating personnel.
Keep the tower clean and the water distribution uniform to obtain continued
maximum cooling capacity. (See Caution note on page 15 and Warning
note on page 17.) Do not allow excessive deposits of scale or algae to
build up on the filling or eliminators. Keep the nozzles free of debris to
assure correct distribution and cooling of water. Uniform water distribution
over the entire fill plan area is vital to the efficient operation of a film-filled
cooling tower.
The capacity of a tower to cool water to a given cold water temperature
varies with the wet-bulb temperature and the heat load on the tower. As
the wet-bulb temperature drops, the cold water temperature also drops.
However, the cold water temperature does not drop as much as the wetbulb temperature. (Wet-bulb temperature is the temperature indicated
by the wet-bulb thermometer of a sling or mechanically aspirated
psychrometer.)
▲ Caution
A tower does not control the heat load. For a given heat load, the quantity of water circulated determines the cooling range. The hot and cold
water temperatures increase with higher heat loads. (Cooling range is
the temperature difference between the hot water coming into the
cooling tower and the cold water leaving the tower.)
Fan Drive
Air is caused to move through the tower by the operation of electric motordriven fans. At full speed, these fans are designed (and pitched) to move
the amount of air required to accomplish the design thermal performance.
Proper utilization of these fans provides the operator a means by which
to adjust the level of thermal performance to suit the requirements of the
load. (See Temperature Control and Energy Management on pages
13 and 14.)
If two-speed motors are used, allow a time delay of a minimum of
20 seconds after de-energizing the high speed winding and before
energizing the low speed winding. Tremendous stresses are placed
on driven machinery and motor unless the motor is allowed to slow
to low speed rpm or less before the low speed winding is energized.
➠
9
Loading...