Patent GB-387326-A (GB)
Title: Improvements relating to the treatment of water
IPC: C02F1/68
Filed: 1931-07-24
Abstract: 387,326. Purifying water. ALLEN, F D C ;14, Church Road, HahweU, London. July 24 1931, No, 21187. [Class 46.] The addition of reagent to a stream of water is controlled by the varying head of water in a vessel having an open discharge orifice through which a secondary stream of water, varying in the same sense as the main stream, is passed. The secondary stream may be deflected from the main stream as by means of weir having a large notch for the tnain stream and a small notch for the secondary stream. An alternative device for deflecting a secondary stream is shown in Fig. 2. The main stream flows through a pipe 20 having an apertured diaphragin 28. Branches 24, 36 connect the pipe 20 above and below the diaphragm 22 with compartments 28, 32 on either side of a diaphragm 34 of a valve 30 which controls the dicharge of liquid from the compartment 28. The pressures in the. compartments 28, 32 willthus be kept equal and this ensures that there will be the same pressure drop across a constriction 26 in the branch 24 as across the diaphragm 22. The flow through the valve 30 will thus be proportional to the main flow. Fig. 3 shows a device for maintaining a secondary flow proportional to the main flow though not necessarily deflected from it. The gauging disc 50 of a flow meter of the Deacon type, situated in the main flow is connected by a cable 46 to one element of a sleeve valve 44 having ports 40, 42, by which the discharge of liquid from a tank 36 is kept proportional to the main flow, the liquid level in the tank 36 being kept constant by means of a float-operated supply valve 38. Fig. 4 shows one means by which the secondary flow of liquid may regulate the supply of a reagent, especially of a gaseous reagent such as chlorine. The secondary flow is delivered to a vessel 16 having a discharge orifice 18 the size of which may be adjustable. The upward thrust on a float 52 due to the head of liquid above the orifice 18 is communicated by a rod 54 to the diaphragm 56 of a valve 60 which regulates the supply of the chlorine to a compartment 62, the pressure in which is thus made to depend upon the liquid level in the vessel 16. The chlorine is delivered from the compartment 62 to the main liquid flow through a connection 64 and a constriction which ensures that the rate of flow varies as the square root of the pressure. A modification of this apparatus is described in which no float is provided but the vessel 16 is suspended from one arm of a suitably counterbalanced lever, the other arm of which communicates thrust to the diaphragm 56. Fig. 10 shows an arrangement in which the thrust of the rod 54 is communicated to the diaphragm 56 through a body of liquid in a flexible capsule 72 of the bellows type. In order to make allowance for variation in pressure of the main flow at the point where the reagent is admitted thereto, a second bellows capsule 94 connected by a pipe 100 to the point referred to, may be provided. Fig. 8 shows an arrangement by which the secondary flow of water can regulate the supply of a liquid reagent. A float 86 in the vessel 16 is connected by a cord 82 or lever to a vertically movable siphon 80 by which reagent is discharged from a tank 76 in which it is maintained at a constant level by a float valve 78. The depth of the siphon outlet below the liquid level in the tank 76 is equal to the distance of the liquid level in the vessel 16 above the outlet 18. A flexible pipe the inlet end of which is connected to the cord 82 or lever may be substituted for the siphon, the outlet end of the pipe passing through the wall of the tank 76.