Operating and Service Instructions
1. TOWER CONSTRUCTION
1.1 Type: CTS incorporates an induced-draft counter-flow design with an axial flow fan mounted on top of the tower to draft air out. The low internal pressure loss and circular-shaped design ensure optimum efficiency and space economy.
1.2 Casing: The F.R.P. (fiberglass reinforced polyester) is composed of fiberglass mat laminated from unsaturated polyester resin. The high structural strength of the material protects the unit against impact and cracking. Gel coat is then applied to form a smooth surface and protect it from ultra violet rays.
1.3 Water Basin: Also made of F.R.P. material. The circular-shaped basin with a cylindrical suction sump keeps cavitation of the pump to a minimum. A drain connection is provided for removal of accumulated dirt from the basin.
1.4 Tower Support Framework
-T-25 –T-2175: The F.R.P. base legs are incorporated with the water basin in a single unit to withstand wind pressure and vibration.
-T-2200 –T-3000: Provided with hot-dip galvanized steel to resist corrosion and rust.
1.5 Motor Support Framework: Made of hot-dip galvanized steel to resist corrosion and rust.
1.6 Air Inlet Louver: The P.V.C. plastic mesh is fitted on the air inlet to prevent foreign material from falling into the basin of water splashing out of the basin.
1.7 Filling: Made of rigid polyvinyl chloride sheet which is embossed and corrugated in a honeycomb configuration. It provides maximum air-to-water contact for highest thermal efficiency.
1.8 Sprinkler Device: Consists of a set of sprinkler pipes and one sprinkler head that is mounted on top of the stand pipe on the cooling tower. The sprinkler is rotated by the pressure of circulating water. There are numerous holes in the sprinkler pipe to allow the water to jet out as the pump impacts rotation.The speed can be controlled by adjusting the sprinkling angle in accordance with the water flow rate. There are two types of sprinkler heads.: T-25 –T-260: The outer casing is made of nylon material; the sliding part is lubricated by the water. T-270 –T-3000: The whole body is made of aluminum alloy and is fitted with sealed type bearings to take thrust and radial loads and to ensure that the sprinkler head revolves smoothly.
1.9 Fan Blade: The cooling tower blades move large volumes of air quietly and efficiently.T-25 –T-230: Made of reinforced plastic material, the blades are coupled to the fan hub by bolts and glue. T-240 & Above: Made of aluminum alloy, the blades are freely adjustable by the pitch angle scale of the fan hub.
2. PREPARATIONS FOR STARTING
2.1 Open the drain at the bottom of the water basin and wash dust and dirt away while scrubbing the water basin with a brush.
2.2 Trial Circulation Water: Fill water in the water basin to the level where the discharge from the ball tap stops. Slowly rotate the sprinkler by hand to check whether it is free. Start the circulating pump, and after washing the interior of the tower and the water pipes thoroughly, refill the circulating water.
2.3 Checking The Tower: After the circulation test, check if there is any dirt or foreign matter sticking to the interior of the tower or the outlets of the sprinkling pipes. Check to see if the speed reducer belt has been adjusted correctly.
After confirming that that the fan revolves smoothly by turning it by hand, check the state of the gap between the tip of the blades and the tower casing. Measure the supplied voltage and make sure that the power supply is in the regulated type. Revolve the fan for a short time and make sure that air is blown upward. Revolve the fan two or three hours to see if any vibrations or abnormal sounds are generated.Slowly move the float of the ball tap up and down and make sure the discharge and control system of water is accurate.In case the tower has been left idle for a long time, check the fol-lowing points and make sure that nothing is wrong. Confirm the insulation of the motor with a meter (see that it is 1MW or above using a 500V meter). See that no loose nuts are found at various important junctions such as the tightened places of fan driving motor and the junctions between the supporting base and the tower casing. Turn the sprinkler with hand and see if it operates smoothly.
3.1 Pump Driving: In order to make the circulating water fill every part of the circulation system, revolve the circulation pump for a short while, to drain the air out of the piping of the circulating water. Before entering steady operation, confirm again that the water basin is filled to the specified level, and then start the pump. Gradually open the adjusting valve and adjust it so that the water will reach the volume specified on the name plate of the cooling tower. When circulation of water becomes steady, check to see if the sprinkler is revolving smoothly and properly.
3.2 Fan Driving: Clean up the surroundings of the tower and make sure that no foreign matter is near the air inlet and outlet.When the equipment goes into steady operation, measure phase voltages and phase currents to see if the motor is operating at the rated current range indicated on the name plate.
4. CAUTIONS DURING OPERATION
4.1 Performance: Since the cooling performance will be affected by the volume of the circulating water, be sure to maintain the regulation water flow at all times.Keep the interior of the tower always clean and take care that no scale or moss grows.
4.2 Water Level: When the level of the water in the water basin drops, air is sucked in and “cavitation” may develop; therefore, it is necessary to keep the water at the proper level at all times.
4.3 Functioning: Pay close attention to the vibration, noise, temperature of the cooling water and electric current during operation and make sure that nothing goes wrong. Vibrations or noises come mainly from the moving parts in the speed reducer and the fan, be careful not to overlook even a slight defect.
5. MAINTENANCE AND CONTROL
5.1 Sprinkler Pipe: The sprinkler pipe must be clean without blockage. If there is some foreign material retarded in the pipe, take the following steps: Loosen the set screw or lock nut on sprinkler device, then remove sprinkler pipe and clean. Align the dot mark on sprinkler head and reinstall.
For T-25 –T-215 models, they are fitted with type A and B pipe (the hole pitch is different to assure even water distribution.
5.2 Sprinkler Head: The sprinkler head rotation will slow or even stop if scale is stuck to it. In this case, check it as follows:
A.T-25 –T-260 - remove set screw cap on top of sprinkler head.-loosen nut and washer, then take head off.-clean it with fresh water and check if any component is worn out.
B. T-270 –T-3000 - remove the cap and take cir clip off.-pull the rotary part off the fixing part and check: replace if necessary.
5.3 Tower Casing: No coating is needed for the tower casing as it is made of F.R.P. If it becomes soiled, wipe it with soap or a water-soaked piece of cloth and then wash it thoroughly with water.
5.4 Water Basin: As dust and dirt are liable to get into the water basin, open the drain at the bottom of the drop-in tank from time to time and wash it clean. This applies also to the water basin in particular, as sediments are liable to accumulate near the outlet, so keep the tank clean so that the strainer mesh will not be clogged.
5.5 Filling: No special care is needed if the control of the quality of water is adequate during operation.
5.6 Fan:Watch the surface of the blades carefully to see that no damage develops and make sure that proper space is maintained between the internal wall of tower casing and the tip of blades.
5.7 Coating: It is desirable to periodically re-coat the metal parts as they are subject to rusting.
6. V-BELT SPEED REDUCER
With increasing public awareness of noise, our engineers have developed a v-belt drive to reduce operating noise levels.This new drive produces much lower noise levels than those obtained from conventional gear drives of the equivalent size. The V-belt is a wide angle (60°C) and is made of a special polyurethane compound with polyester tension cords (tensile member). Very compact V-belt drives are possible with this belt.With proper maintenance, the V-belt drive will operate reliably; however, proper maintenance is essential and the following instructions are very important.
6.1 Belt Adjustment: Before operation, open the adjustment access cover and check whether the washer on the adjusting bolt is aligned with the adjusting gauge. (Ref. Fig. A) Tighten the adjusting nut if necessary. During operation, the belt may stretch, allowing belt slip and abrasion. Hence, the belt tension should be checked according to the following: 50 hours after commissioning. Thereafter, carry out 3 checks, each at 100 hour intervals.
After the 4thcheck, at 350 hours, then check each month.
Off-Season Shut Down –For a long-time shut down, slacken the adjusting nut 4-5mm to prevent bolt stretch. Re-adjust belts prior to putting the cooling tower back into service.Adjustment Precaution –If a gap exists between the adjusting gauge and the washer, the belts are too slack. If the washer and the adjusting nut overlap the adjusting gauge, the belts are too tight.The life of the belts depends on the maintenance of proper tension. The adjusting gauge is factory set and should not be altered.
6.2 Testing of Drive Operation: After checking the belt adjustment, spin the fan by hand to see whether it is free. If it spins freely and smoothly, start the fan motor. After 2 to 4 hours operation, check amperage and voltage and compare the readings with motor nameplate data. Check the motor temperature and check noise and vibration.
6.3 Maintenance: The following work should be performed.
Drive Section: Clean out the inside of the driving section annually.
Motor Insulation: Before putting the tower into service in each cooling season, check the motor insulation with a 500 Volt Meter. A resistance greater than 1MW is acceptable.
Bearings: Although it is unnecessary to lubricate the sealed bearings, an annual change of grease will extend their life. To repack the bearings, remove the seal plates with a sharp tool inserted as indicated by the arrow in Fig. B. Replace the seal plates after replacing the bearings.
7. PRECAUTIONS IN PROLONGED IDLENESS
Unless the circulation water is drained, it may freeze in winter and cause the pipes to crack. If the drain of the drop-in tanks kept open, rain-water and snow water will not accumulate in it. Make sure that tightening bolts on the various parts of the tower, especially on the moving parts are tight. As the cooling tower is installed on top of the roof, it is desirable to cover up the tower casing and the air exhaust outlet.
8. WATER TREATMENT
Bacterial Contamination: Bacterial contamination of recirculated water in the cooling tower is possible.It is therefore recommended that, after the cooling tower is commissioned, a regular maintenance program be investigated. This should included treatment of the recirculated water. As we are not experts in this field, we strongly recommend that a reputable water treatment company be consulted for the treatment of the system’s recirculated water.