Operating Instructions RF-2000
8
1.6 Precautions on Static Electricity
Liquid chromatography using flammable organic solvents as mobile phase requires
proper care against fire, explosion, etc. Particularly, among various possible
accidents, those caused by static electricity are difficult to anticipate, and tend to
occur only with unexpected conditions which often make countermeasures
insufficient. At a site where preparative liquid chromatography is practiced, a large
amount of flammable substances may be used. Therefore, once an accident
happens, it could lead to tremendous damage. The mechanism of accident caused
by static electrical discharge and preventive measures are described below. Take
due care in safety measures in handling of equipment.
1.6.1 Mechanism of Static Electrical Discharge Accident (Example)
Accidents caused by static electricity take place through the following processes.
When liquid is fed at high speed through a small-diameter tube like the pipe of a
liquid chromatograph, static electrical charge occurs by friction between solid and
liquid as shown in the figure below
Fig.: Occurrence of Static Electricity by Friction between Solid and Liquid
When the charged liquid is collected in an insulated vessel, the static charge
accumulates gradually, and the voltage can easily reach a few kilovolts. If some other
conductive object is brought near the vessel, electricity is discharged at a certain
distance from the vessel releasing heat energy. If flammable gas of sufficient
concentration exists nearby, ignition is caused by this energy.
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