When looking at the specification of float switches, you will find a parameter called Specific Gravity. What is the meaning of this parameter?
Specific Gravity is the ratio of object density to that of water. It’s related to but not the same as density.
Sometimes it’s also called Liquid/Fluid Specific Gravity. Since the specific gravity of water is 1 at sea level, liquids and substances with a specific gravity lower than 1 will float in water. Thus, before selecting the right level sensor for your application, it is important to understand this parameter.
For example, LLF59Y100JC from Cynergy 3 has a low specific gravity (around 0.45). This device will float well in most petroleum products ranging from 0.7 to 0.86 specific gravity. If using a float switch with a specific gravity of 0.8 such as RSF78Y100RN from Cynergy 3, it will float well in water but will sink in alcohol which has around 0.72 specific gravity.
Below are specific gravity figures for different liquids:
|LIQUID||Specific Gravity @ 60°F / 15.6°C|
|Tap Water (Reference)||1.0|
|Automotive Oil||0.88 – 0.94|
|Carbon Tetrachloride CCl4||1.59|
|Crude Oil||0.79 – 0.86|
|Diesel Fuel Oils 20||0.82 – 0.95|
|Gasoline||0.68 – 0.74|
|Kerosene||0.78 – 0.82|
|Jet Fuel (av)||0.62|
|Lard Oil||0.91 – 0.93|
|Machine Lubricants||0.88 – 0.94|
|Milk||1.02 – 1.05|
|Sodium Chloride 5%||1.037|
|Sodium Hydroxide (caustic soda)||1.22|
|Sulphuric Acid 95%||1.839|
|Sulphuric Acid 20%||1.14|
|Turpentine||0.86 – 0.87|