IOV Thermostat

Forum to discuss all areas of lighthouse technology such as optics, fuels, fog signals, radiobeacons, daymarks, construction, etc.

Postby island » Fri Apr 22, 2005 3:30 pm


Thank you for sharing your experience with us. And from your experience what was the most troublesome problem one might have keeping the IOV operating properly?

I like you description of observing the lens rotation from the ground below. At 8 minutes per revolution, a first order lens would be rotating at about 1/2 inch per second which would be difficult to observe from the ground 70 feet below.

Concerning the thermostat, I do not know what temperature was expected with the IOV lamp operating properly. The gauge or dial indicator on the thermostat diagram I have shows a temperature range from 180 to 600 degrees F. The mid point is 390 degrees.

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Postby Fred » Sat Apr 23, 2005 12:10 pm


There is some information on Chance lamps at :-

They were down to there simplist form when I used them,the main consideration when lighting was that enough time was allowed for the pre-heater to heat the vaporiser,otherwise when you opened the feed valve you would have a jet of paraffin,which if ignited would result in loads of sooty specks everywhere,a cleaning job for the culprit who would almost certainly remember the next time (No it never happpened to me)

The other thing was regular cleaning,you then had no problems.

The main body and mixing chamber were washed in soapy water,the vaporiser and bunsen we heated with a blowlamp,which dried and helped carbonise any debris.Then the nipple bolt and cleaning bolts were removed and the inside of tubes cleaned with a corkscrew shaped wire brush,with the 55 mm vaporiser a scraper was used to clear the passageway between the two tubes and the nipple cleared with the apropiate sized wire.
The bunson tube took the time,since each individual hole was pricked and cleaned and hopefully any bits would then be blown out of the feed tube.
The lamp was then reassembled returned to the lightroom and given a check operation.

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Postby island » Mon Apr 25, 2005 5:59 pm


Thank you for the description of the Chance lamp operation. This lamp differs somewhat from the IOVs used by the US Lighthouse Service but the operation was very similar.

One concern mentioned in the IOV instructions was that of fuel cleanliness. It was recommended the fuel be filtered when filling the carrier from the storage container and again when filling the lamp tank from the carrier.

Concerning flame temperature, it was stated that if the lamp surges or the mantle rises it it too hot. If the lamp spits flame occasionally it is too cool. If the lamp flame is too blue around the sides too much fuel is being burned. This may be caused by to cool a lamp, to great a pressure or too large a vaporizer nozzel. There should always be a slight blue flame around the mantle. Optimum operating pressures were 40 psi for a 35mm lamp and 60 psi for a 55mm lamp.

Instuctions were obviously helpful, but it also very important for successful operation that the keeper carefully observe and understand the behavior charateristics of his specific lamp.
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