Cooling Tower Fan Blade Balancing

Where is the 0 65 in sec at 1200 cpm coming from.

Cooling tower fan blade balancing.

The purpose of a cooling tower is removal of excess heat from water used in industrial processes to cool various systems. These balance categories are ordered from a less sensitive group hvac to the most sensitive fans which include those for petrochemical processes and computer chip manufacturing. Thru balancing of the cooling tower fan we were able to reduce the 1x rpm fan vibration levels significantly from 72 mills to 2 5 mills at 330 rpm or from 19 mills to 0 6 mills at 240 rpm. And the fan has three fiberglass blades.

We also offer shop services balancing motor armatures flywheels and crankshafts. The principles presented however can be generally applied to many rotating components. The air flow is produced by the fan which is driven by the motor either in direct drive or by gear speed reducer. The air movement and control association intl inc s amca standard 204 balance quality and vibration levels for fans recognizes five different fan application categories bv 1 bv 2 bv 3 bv 4 and bv 5 for the required balancing grade during manufacturing of the fan see table.

This document covers impellers while systems see amca standard 204 and ansi standard s2 19 are covered by air. This document is intended to apply specifically to system vibration and mechanical balancing as related to fans and blowers. Possible causes were unbalance due to dirty or damaged fan blades or a problem with the gearbox mounting structure. Frequencies present at cooling towers.

Fan speed motor speed blade pass frequency. The latter would allow the gearbox to rock in a direction parallel to the input shaft. A likely structural natural frequency was identified at 310 cpm. The equipment we have balanced ranges from small blowers to the largest of cooling tower fans.

The vibration levels at both motor fan speed are to be measured at the motor while the vibration levels at the blade pass frequency is to be measured at the fan shroud or stack. The fan was balanced to 0 5 mils but there was a high 0 65 in sec at 1200 cpm. Dynamic balancing of the cooling tower fan. Dynamic balancing cornell balancing offers on site service to perform single and two plane balancing service of all rotating equipment.

Removal of the heat from the water is done carried out by the flow of the water counter or across to an air flow.