Patent GB-687583-A (GB)
Title: Improvements relating to means for discharging liquids from vessels
IPC: E03D1/12
Filed: 1950-04-14
Abstract: 687,583. Siphon-discharge water-wastepreventers. NICCOLAI, R. April 14, 1950 [April 21, 1949], No. 9262/50. Class 26 A device for discharging liquids from receptacles, e.g. water-waste-preventing cisterns, comprises a tank divided into two compartments, one having pipes 6, 7, 9, 10 forming a double siphon - the inlet A of which is in the cistern and the outlet B of which communicates with the discharge pipe C - and the other forming a hydrostatic trap which communicates with the inlet pipe 6 of the double siphon through an aperture 11, in the partition separating the trap from the first compartment, slightly below the summit 13 of the wall between the pipes 6, 7, the priming of the double siphon being effected by reducing the pressure-head within the trap by means of a small controlling siphon 16, 17, 18. In the form shown, when water is admitted to the cistern, after the device has been assembled therein, it rises in the pipe 6, some flowing via the aperture 11 into the ducts 1-4 and some overflowing at 13 so that, as the water continues to rise, a column of water is formed in the pipe 9 between the levels 24 and 35. As the cistern water level continues to rise, the air in the pipe 7 is compressed and, via an aperture 5, depresses the water in the ducts 1 and 2 so elevating it in the ducts 3, 4. When the water in the ducts 3, 4 reaches the level 25 it primes the controlling siphon 16, 17, 18'which discharges via an aperture 19 into the pipe 10 and so prevents the water level rising beyond level 25. When the head of water in the cistern exceeds that between levels 14 and 25 in the trap, the air in the ducts 1, 2 is forced under level 14 and the pressure in the pipe suddenly reduced so the double siphon 6, 7, 9, 10 primes and discharges the cistern. On the next filling, the rising water in the cistern flows into the trap and the pipe 9 as before but when the water in the ducts 3, 4 rises to the level 25 the controlling siphon does not prime owing to an air lock in the pipe 17 caused by the water remaining in the base of the controlling siphon from the previous filling. The water in the ducts 3, 4 thus continues to rise to the level 15 and, since the maximum head in the cistern is arranged to be less than that between the levels 14 and 15, the trap is in hydrostatic equilibrium. When the button 23 is operated the air thus compressed in the pipes 20 and 22 overflows some of the water in the pipe through the aperture 19 and into the outlet so that the controlling siphon primes and reduces the water level in the ducts 3, 4. When the head between the level 14 and the water level in the ducts 3, 4 is reduced to less than the head in the cistern, the air in the ducts 1, 2 is forced under the level 14, the double siphon 6, 7, 9, 10 primes and the cistern flushes. A small siphon 30, 31, primed by the flushing water ensures that the double siphon 6, 7, 9, 10 is completely emptied after each flush. The push-button 23 may be eliminated, the cistern flushing automatically when the head of water in the cistern exceeds the head between the levels 14 and 15.