Patent GB-910293-A (GB)
Title: Pneumatic control head, particularly for weighing machines
Inventor: KIRKHAM JOSEPH EDWARD
IPC: G01G19/22
Filed: 1959-12-10
Abstract: 910,293. Weighing-apparatus. BRISTOWES MACHINERY Ltd. March 8, 1961 [Dec. 10, 1959], No. 41978/59. Class 143. [Also in Group XXIX] An automatic pneumatic weighing machine has control heads in each of which a bleed valve is actuated from a spindle whose rotation is controlled by a weight-sensing device, the actuation being through magnetic attraction. When a button 46 is depressed it opens a valve 47 and compressed-air flows from an air line 39 through a control head 35, bleed valve 9a and line 45 to a control valve 49. The bleed valve 9a is already open because of the position of an arm 37 on a spindle controlled by a weight-severing device. The control valve 49 operates to allow compressed-air to operate a valve 54, via line 50, valve 52, and line 53, and the valve 54 operates to allow air from an air line 40 to operate a pneumatic exit valve 32 of a storage container and aggregate of one sort commences to fall into one compartment of a divided weigh hopper 30. Similarly, a valve 57 moves to operate an exit valve 34 and binder commences to fall into a weight hopper 31. Weight-sensing device, of known design, controlled by the hoppers 30, 31 move arms 37, 38 in control loads 35, 36 in the directions X, Y. The bleed valves may be altered in position according to the weight of aggregate required to be fed. Thus, when the weight in the hopper 31 is such that the arm 38 carries opposite a bleed valve 9d, this valve opens through magnetic attraction (see Group XXIX) and air flows through a line 58 to operate a valve 55 which in turn closes the valve 57 and stops the air supply to the exit valve 34 which closes and cuts off the supply of binder. Similarly, when the desired weight is in the hopper 30, the arm 37 carries opposite a bleed valve 9b which operates the valve 52 which, first, operates the valve 54 to shut the exit valve 32 and cut-off the supply of aggregate and, secondly, operates a valve 59 to supply compressed-air through a line 60 to a valve 61 which in turn opens the exit valve of a storage container with aggregate of another sort, which commences to fall into the other compartment of the weigh hopper 30. The weight-sensing device controlled by the weighing hopper 30 cause the arm 37 to continue to rotate until it comes opposite a bleed valve 9c, the position of which is set for the weight of the second aggregate, and the valve 9c opens, causing air to be supplied to the valve 59 which operates the valve 61 to close the exit valve 33. After the material has been weighed out in the required proportions, air flows through a line 67, following the last operation of the valve 59 and operates valves 68, 69 to open doors 63, 65 and allow the binder and one sort of aggregate to fall into a mixer 66 and the air in the line 67 also causes a piston 72 to start timing switches 70, 71, the object of which is to mix one aggregate with the binder for a certain time before another is added and to control the overall mixing time. When, after the pro-set interval, the switch 71 closes, a valve 73 operates to open a door 64 and allow the other sort of aggregate to drop into the mixer 66. When the mixing time has elapsed, a valve 74 operates to cause a door 75 to open below the mixer and release the mixture. Suitable interlocks may be provided between the feeds and release doors, and over-riding manual control of the exit valves.