Inspection and repair on FLENDER B2-SV-09-D gearbox

This client from Belgium came to us with this FLENDER B2-SV-09-D. We inspected the gearbox and performed a repair. After a succesful testrun we shipped the gearbox back to the client.

This report shows the results of visual inspection on the cooling tower fan gearbox. GBS was commissioned to determine the state of the gearbox. The state of the gearbox can be considered unacceptable, this conclusion due to corrosion of the bearings and pitting on the 2nd stage.

The surface-bonded corrosion will cause indentations on the teeth and the bearings. In addition, free particles of corroded material will be transported through the gearbox into the oil and accelerate the wear of bearings and gears.

Pitting has been observed on the output gear. Several factors influence this, including surface roughness, lubrication and tooth maturation. The damage is characterized by small pits in the tooth flank as a result of surface weakening. Pitting can be stabilized or progressive, in the latter case it can develop into heavier pitting, peeling and peeling.

In addition to corrosion of the interior of the gearbox, the unprotected metal on the outside of the gearbox is also corroded, particularly relevant on the races of the seals. The corrosion will accelerate the wear of the seals and cause oil leakage. In addition, water can enter the gearbox due to the reduced sealing of the seals.

We advise:

- Carry out a complete overhaul of the gearbox, ie replacement of all bearings and seals
- Renew the treads of the seals
- To renew the gear of the 2nd stage as a result of pitting
- Mount an oil filter
- Clean the gearbox internally
- Perform a visual inspection and a vibration measurement annually.