Inertia safety switch

INERTIA SAFETY SWITCH

The inertia switch has the task of interrupting the electrical supply for the electric fuel pump if the vehicle undergoes violent deceleration (impact) to prevent fuel from escaping and creating a fire hazard if the fuel manifold or the supply pipe are damaged.

The switch is made up of a steel ball in a conical shaped housing kept in position by the attraction force of a permanent magnet.

Under the action of the acceleration due to the inertia force the ball can be released from the magnetic clip and gradually come out of the conical housing with an upwards movement depending on the angle of the cone.

Above the ball there is a rapid attachement mechanism which forms a normally closed (NC) circuit. When struck by the ball, the mechanism changes position to the normally-open (NA) circuit, thereby interrupting the electrical supply to the electric pump causing it to cut out.

The calibration of the switch causes its operation at acceleration above 1.2 g (about 11.7 m/s², corresponding to an impact at a speed of around 25 Km/h).

The switch can be restored by pushing the upper button protected by a flexible cover.

After an apparently slight impact, if there is a smell of fuel or there are leaks from the fuel system, do not turn the switch back on, but search for the problem and eliminate it to prevent the risk of fire.
If this is not the case and there are no leaks and the vehicle can be driven again, press the button to reactivate the electric pump.

SINGLE-ACTING ANTI-FLOW VALVE

This is a safety valve fitted in the fuel return pipe near the tank.

The valve allows the return of fuel to the tank preventing it, however, from flowing out in the opposite direction if the pipe breaks.