Resilient Isolators
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| Illustration 1 | g00745665 |
(1) Rubber element | |
Each isolator has four rubber elements. The most usual cause for failure of the isolator is oil contamination of the rubber elements. Inspect the rubber elements of each isolator for the following conditions.
- Swelling
- Blistering
- Cracking
Perform the following procedures when deterioration of the rubber elements is initially observed:
- Record the observation in a log.
- Check the alignment of the driven equipment.
After deterioration of the rubber elements is initially observed, the rubber elements must be carefully inspected. Any further deterioration of the rubber elements must be recorded. The isolator must be repaired or replaced if rapid deterioration of the rubber elements is observed.
Deterioration of the rubber elements is usually accompanied by settling of the isolator. Settling of the isolator will result in misalignment between the engine and the driven equipment.
Ensure that the covers are in the correct position and that the O-rings are in good condition. This will help prevent water from entering the top of the mount. Water may cause the adjustment screw and/or the locknut to seize.
Measure the Height of the Isolators
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| Illustration 2 | g00705353 |
There are two methods of measuring the heights of the isolator:
Acceptable - This method does not take into account deformation of the bed of the engine. Measure the loaded height of each isolator. Use an inside micrometer and measure dimension (A) between the top of the soleplate and the bottom of the engine support assembly. All measurements must be taken at the location that was marked by the manufacturer of the vessel at the time of the engine commissioning.
Preferred - This is the most accurate method. This method will ensure that each of the mounts are carrying the same load. Measure each corner of each isolator (B) and record the average height of the four measurements from each isolator.
Compare the measurement to the height that is stamped on the mounting foot of the engine or compare the measurement to the specifications from the report from the engine commissioning. If the measurement has changed ± 1 mm (± 0.04 inch) from the recorded height, the height of the mounting foot must be adjusted back to the original specifications. See this Operation and Maintenance Manual, "Engine Mounts-Inspect" for information on adjusting the engine mounts.
Note: It is important to keep accurate records of all of the measurements so that trends can be developed for the life of the isolators.