"but I would be very careful about any type of switch or relay in the vicinity of the tank, especially under the cap. Note that the Robertshaw transmitter is rated "intrinsically" safe whatever that means."
http://www.engineeringtoolbox.com/ha...ion-d_345.html
The electrical classification of a propane tank would probably be Class 1 Div 2 which indicates that hydrocarbon vapor could be present in abnormal situations e.g. a leak during filling.
In this classification, intrinsically safe equipment is required.
http://en.wikipedia.org/wiki/Intrinsic_safety
Safety of design cannot be stressed enough when it comes to dealing with hydrocarbons, especially when vapor can exist.
I ran across this use of load cells for a large propane tank (I have been considering a similar problem for a 275 gallon heating oil tank in the basement)
http://www.propanecouncil.org/uploadedFiles/11722.pdf
While they were not happy with the cost effectiveness of their result, the concept of using a load cell is appealing. For a fill/no fill decision I would think a single load cell would be sufficient. Mounting such a device in an as-built situation may be an issue however.
Mark
http://www.engineeringtoolbox.com/ha...ion-d_345.html
The electrical classification of a propane tank would probably be Class 1 Div 2 which indicates that hydrocarbon vapor could be present in abnormal situations e.g. a leak during filling.
In this classification, intrinsically safe equipment is required.
http://en.wikipedia.org/wiki/Intrinsic_safety
Safety of design cannot be stressed enough when it comes to dealing with hydrocarbons, especially when vapor can exist.
I ran across this use of load cells for a large propane tank (I have been considering a similar problem for a 275 gallon heating oil tank in the basement)
http://www.propanecouncil.org/uploadedFiles/11722.pdf
While they were not happy with the cost effectiveness of their result, the concept of using a load cell is appealing. For a fill/no fill decision I would think a single load cell would be sufficient. Mounting such a device in an as-built situation may be an issue however.
Mark
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