Patent GB-190916947-A (GB)
Title: Improvements in Regulating Apparatus.
Inventor: MACHLET GEORGE
Filed: 1909-07-20
Granted: 1910-08-22
Abstract: 16,947. Machlet, G. July 20. Burners, regulating and controlling.-A generally-applicable regulating-apparatus, which may be used with furnaces for hardening steel and heating metal, &c., or with other heating or cooling apparatus, and for starting or stopping mechanism, and specially suitable for use with indicators having delicate index needles, comprises two levers which are alternatively caused to dip at predetermined points in the path of the indicator, and which when intercepted by it cause opposite changes in the condition of the apparatus ; when the indicator has moved so as to indicate a certain condition of the apparatus to be regulated, it intercepts the then moving lever, which is automatically latched out of use, and effects a change in the condition of the apparatus which causes the indicator to move towards, and eventually to intercept, the other lever, now automatically set in motion. The levers may be operated by the oscillating arm of a diaphragm motor actuated by compressed air. The invention is illustrated as applied for regulating and controlling the temperature of a furnace. The furnace burners 2, Fig. 5, are supplied with air and gas from pipes 63, 64 respectively, through a regulating-valve 61, divided into two parts by a partition 65 and operated by a diaphragm 58. A thermo-electric element 3 is connected to the moving coil 7 of a galvanometer or volt-meter 6, the needle 8 of which shows on a scale 9 the furnace temperature. Two levers 10, 75, having projections 11, 77, Fig. 41, and so arranged that when one is operating the other is latched out of use, are arranged over a portion of the scale, and as the needle swings over from zero while the furnace is being initially heated, the projection 11 repeatedly dips in the path of the needle. These levers are operated through universal joints 25, 80 by bent levers 29, 82, swinging on a common axis 24 and connected to springs 22, 87 which tend to force the teeth 11, 77 into the path of the needle. The reciprocating arm 15 of the compressed-air engine 13 actuates the levers 29, 82 through the connected levers 16, 86, which oscillate about the common shaft 17 and are secured by a spring 33 to a fixed stud 35 on the frame. As the bent end 20 of the arm 15 performs its downward stroke, the shoulder 18 engages the pin 21 on the connected levers, oscillating them about the shaft 17 and allowing the bent end 30 of the lever 29 to fall as the inclined edge 32 passes beneath it. The spring 33 at first opposes the movement, but when the connected levers pass the dead-centre the spring swings them over until they are arrested by the bent lever end 30 coming into contact with an abrupt edge 36 on the lever 16, Fig. 7. On the up-stroke of the arm 15, the shoulder 19 lifts the pin 21 and the spring 33 swings the connected levers back into their original position. The projection 11 has meanwhile dipped idly into and out of the needle's path. Eventually the needle 8 swings beneath the projection 11, accidental movement past it being prevented by a guard 37, and stops its downward motion. The lever end 30 is thus prevented from falling along the inclined edge 32, misses the edge 36, and allows the lever 16 to be pulled over by the spring 33. The part 42 of the lever edge raises the lever end 30 into engagement with a latch 40, Fig. 9, pivoted at 41 upon the framework, which the pin 39 on the connected levers simultaneously moves into position. The needle guard 37 is thus raised clear of the needle, which is then capable of indicating any further temporary increase in the furnace temperature. Fixed to the latch 40 is a latch 85, and as the former is thrown into gear and renders the lever 29 inoperative, the latter is pushed over and so releases and renders operative the lever 82. The bent end 83 of this now engages the lever 86 and these operate similarly to the previously-described action of the levers 29, 16. At each reciprocation of the lever 15, the lever end 83 moves along the incline 89 and striking the edge 90, Fig. 15, arrests the connected levers, the projection 77 meanwhile dipping in the needle's path, until the volt-meter needle is arrested by the guard 78 and stops the downward movement of the projection. The lever end 83 then misses the stop 90, and is raised by the cam-edge 91 of the lever 86 into engagement with the latch 85, which is moved into position by the pin 21, Fig. 17. Simultaneously the projection 77 and its needle guard are raised out of the needle's path, and the catch 40 is swung back to release the lever 29, which again begins to reciprocate the projection 11 in the path of the needle. The pin 39 of the connected levers is prolonged and acts between shoulders 48, 49 on a valve-rod 44, Fig. 5, so that when the projection 11 is engaged by the volt-meter needle and the pin 39 swings to its upper limit, the valve 92 is raised, and the space beneath the diaphragm 58 is cut off from the compressed air pipe 93 and connected by a pipe 54 and ports 100 with the exhaust pipe 55. The diaphragm 58 falls and the valve 61 nearly cuts off the supply of air and gas to the burners. When the furnace temperature falls and the needle 8 consequently recedes and engages the prejection 77, the pin 39 is swung over to its lowest position and the valve 92 is dropped so as to cut off the pipe 54 from the exhaust 55 and connect it by ports 96, 100 with the compressed-air pipe 93. The diaphragm 58 and the valve 61 are raised and a full supply of gas and air is admitted. As the furnace temperature again rises, the needle 8 swings back to the projection 11 and the fuel supply is again reduced. The temperature is thus kept within narrow limits. The levers 10, 75 are pivoted upon an arm on a cuplike support in two parts 101<a>, 101<b>, Figs. 5 and 41, secured together by screws. The cup is capable of being rotated by a worm-wheel segment 108 on its upper part which is actuated by a worm 107, and the levers 10, 75 can thus be adjusted to any part of the scale 9. Rests 38 are provided to support the needle when it engages a projection 11 or 77. The rests 38 may be cast together, and may have inner and outer flanges 111, 110; they may be supported by an arm extending from a part inside the box. The arm 15 is operated by a reciprocating diaphragm 12, compressed-air supply to which is regulated by a distributing-valve 116. A spring 119 coiled round a fixed rod or fulcrum 147, Figs. 23 and 25, engages at one end a swivelled pin 149 on the arm 15, and at the other end the valve 116. On the framework is pivoted a latch 144, Fig. 35, provided with a spring 152 and having a shoulder 145 which engages a lug 146 on the valve and so retains this in the up or down position. Fig. 28 shows the diaphragm commencing the down-stroke. The compressed air from the pipe 93 passes by way of the passage 127, the ports 130, 131, and the passage 133 to the upper side of the diaphragm, the air exhausting from the underside by the passage 122, Fig. 25, and the ports 125, 126 to the exhaust pipe 57. When the arm 15 reaches the bottom of its stroke, a pin 154 on it strikes the latch arm 155, releases the pin 146, and so allows the spring 119 to snap the valve into its upper position, Fig. 23, in which it is held by the latch 144. Compressed air then enters from the passage 127, through the ports 130, 125 and passage 123, to the space beneath the diaphragm, which is thus raised. Air exhausts from the space above the diaphragm through the passage 133, the ports 131, and passage 137 to the exhaust pipe 57. When the arm 15 reaches its upper limit, a pin 150 strikes the latch arm 151, Fig. 23, and releases the valve 116, which is forced down to its lower position by the spring. The diaphragm descends again, the valve 116 being held down by the latch until the down-stroke is completed. The speed of the air-engine is regulated by the throttle screw 138, Fig. 28.