Recently Ravebo was requested by Vroon Offshore B.V. to mobilize an engineer for one of their vessels to carry out the annual calibration & certification of their Georim GBA-155 15PPM bilge alarm.
An oily water separator is a piece of equipment that separates the oily water mixtures (and other contaminants) what comes out the vessels’ bilge that can be harmful to the World’s oceans. In order to protect the environment the IMO published regulations that all vessels build after 2005 have to be equipped with an oily water separator that is able to achieve clean bilge water to a purity of under 15ppm. These separators must also be fitted with an alarm system that will automatically shut down the pumping overboard when the quality of the water exceeds the 15 ppm limit. The bilge alarm continuously measures the concentration of oil in water and generates an alarm when the oil concentration exceeds the 15ppm level.
When carrying out the calibration on a 15PPM Bilge alarm, below process includes but not limited to the following procedures:
1. Testing with clean water, to adjust 0PPM
2. Testing with test gain liquid, to see if the unit recognizes the required PPM value (this is normally 5 or 15PPM) correctly.
3. Re-testing again with clean water, to see if unit recognizes 0PPM.
4. Perform a simulation test (i.e. testing if overboard valve is triggered and closes at the required PPM value but at a max of 15PPM. The response time of this unit should not exceed 5 seconds.
5. Checking of the sensor unit, manually done by our engineer.
6. Checking that GMT time and date are correct.
7. Checking that the units’ data logger is functioning correctly and that data is being logged correctly. The unit is required to hold a minimum of 18 months of data and should be able to display this or a print for official inspections if requested by the authorities.
Whilst carrying out the service, it became clear that there was a problem with the unit, as it was constantly showing high incorrect values. After carrying out the normal adjustments on the main PCB without success, further troubleshooting was required. This troubleshooting soon led us to the measuring cell. The measuring cell was giving false readings to the master unit. Having carried out the normal cleaning, glass tube replacement and value measuring without success it was decided with the vessel that the measuring cell should be replaced. After the change out, we again carried out the tests, making minor adjustments where required. Having completed several tests and demonstrations to the vessel, the unit was given its clean bill of health and our certification.