Trigger mechanism for siphon apparatus

In a liquid siphon for discharging liquid from a tank at the end of a discharge cycle;

• said siphon having a flow pathway comprising a plurality of legs and a plurality of bends interconnecting said legs;
• one of said bends comprising a first liquid trap having a predetermined maximum fill level associated with the tank being substantially empty and one of said bends comprising an air trap;
• said air trap being positioned upstream of said first liquid trap;
• said siphon also including filling means to fill said first liquid trap after discharging said liquid from said tank and before a subsequent filling of the tank;
• the improvement comprising a device for eliminating liquid received from said filling means in excess of the amount required to achieve the maximum fill level in said first liquid trap associated with the tank being substantially empty and for triggering the discharge of the liquid from said tank when the liquid therein reaches a predetermined level;
• said device comprising:
• (a) a second liquid trap having an outlet at a downstream end thereof and an inlet at an upstream end thereof;
• said outlet having a level being not elevated above the maximum fill level of said first trap associated with the tank being full;
• and
• (b) flow means connecting said inlet of said second liquid trap and said first liquid trap and cooperating with said filling means, such that when said first liquid trap is filled greater than said maximum fill level associated with the tank being substantially empty by said filling means, then excess liquid in said first liquid trap flows through said flow means to said second liquid trap and such that when no excess liquid is in said first liquid trap, then said flow means communicates with said air trap.