Patent GB-643865-A (GB)
Title: Improvements in or relating to an electrical chlorine concentration limit indicator
IPC: C02F1/76
Filed: 1947-06-24
Abstract: 643,865. Determining physical qualities of material; resistance measurements. WALLACE & TIERNAN PRODUCTS, Inc. June 24, 1947, No. 16644. Convention date, July 13, 1946. [Class 37] [Also in Group XXXVII] In a chlorine injection system for chlorinating aqueous liquids an electrical instrument is provided responsive to a relatively high concentration of chlorine in a relatively small stream of water added to the liquid to be chlorinated.. The aqueous liquid to be chlorinated passes through a main pipe 1 having a branch pipe 2 through which a stream of water passes. Chlorine is supplied from a chlorinator 3 to the throat 5 of a Venturi in the pipe 2 so as to maintain in the stream of water a concentration of chlorine many times that required for the liquid in the main 1. A predetermined portion or all of the liquid flowing through the pipe 2 is passed through a cell 6 having electrodes 9 of silver or other metal comparatively inert to chlorine. The electrodes are connected in an A.C. circuit comprising the low-tension secondary of a transformer 15, a rheostat 16, and a full-wave rectifier 17. The D.C. output of the rectifier 17 is supplied to the winding 19 of a relay 20, the rotor of which comprises a permanently magnetized disc 23 of magnetic material of high retentivity. A projection 24 of this disc is welded to an offset portion 25 of the rotor support, which is pivoted and carries a pinion 29. This meshes with teeth formed on a sector 30, which is connected by a flexible spring 33 to a rigid support 32. The spring 33 carries a contact 34 co-operating with a stationary contact 35 so as to close a circuit when the concentration of chlorine in the cell 6 falls below a predetermined amount. This circuit includes a second relay 38 which closes a circuit containing a lamp 48, serving as a visual signal, and the primary of a step-down transformer 49. Across the secondary of this is a buzzer 50 and a full-wave rectifier 51, the D.C. output of which is connected to the winding 54 of a recording instrument 55, which records on a circular chart carried by a member 57 rotated by a synchronous motor 58. A pen 59 is carried by an arm 60 rigid with a bracket rotatable about a screw 62 by which the radius at which the pen 59 marks the chart may be varied. Also mounted for rocking movement about the screw 62 is a frame comprising end members 66, 6 7 connected by a cross-bar 68. The bracket carrying the arm 60 loosely embraces the cross-bar 68 so that this bracket and the frame may be rocked simultaneously about the axis of the screw 62. The frame is connected by a link 69 and spring 71 with an armature 70, which is normally held in its " off " position by a spring 73. When the winding 54 is energized, the armature 70 is attracted and the pen 59 is brought into contact with the chart so that a line is marked thereon for the time during which the chlorine concentration is below the desired amount. The radius at which the pen operates may be changed daily by rotating the screw 62, so that a separate line is marked for each day. Specification 548,174 is referred to.