Patent GB-138640-A (GB)
Title: Improvements in temperature controllers
IPC: G05D23/12
Filed: 1920-02-04
Abstract: 138,640. Tagliabue Manufacturing Co., C. J., (Assignees of Roesch, A.). Aug. 28, 1914, [Convention date]. Thermostats.-The supply of heating or cooling medium to a vulcanizer or like apparatus is automatically controlled for a period of time in such a way that the temperature is caused to vary according to any predetermined time-temperature curve, and means are provided for discontinuing the heating or cooling at the end of the predetermined time. In the arrangement shown, the supply of steam through a pipe 50, Fig. 1, to a vulcanizer 13 is controlled by a valve 49 operated by a diaphragm 48, the air pressure on which is regulated by a double-faced valve 35, Fig. 2, in a valve body 37<a> located in the pipe system 47, 40, 41 communicating between the diaphragm 48 and a tank 42 for compressed air. One face 35 of the valve regulates the passage 38 from the pipe 40, while the other face 36 regulates the passage 39 opening to the atmosphere. The valve stem 34 is actuated in one direction by the air pressure, and in the opposite direction by a projection 15<a> on a pivoted lever 15, which at its lower end carries a clock-work mechanism in a casing 17. Mounted on the hour spindle 20 of the mechanism is a cam 21 which is shaped in accordance with the predetermined time-temperature curve and abuts against a roller 24 carried by the lower end of a lever 25 pivoted on the main-lever 15. A strong spring 32 is arranged between the upper ends of the two levers 15, 25 and a weak spring 33 between the lower end of the lever 25 and the frame 10 supporting the levers. A contact 27 carried by the lever 25 engages a capsule 29 in communication with a thermo-sensitive element 31 in the vulcanizer 13. In operation, any undue rise of temperature in the vulcanizer would cause the contact 27 to be driven to the right, causing the levers 15, 25 to pivot in unison, and withdrawing the projection 15a from the valve stem 34, thus allowing compressed air to pass into the pipe 47 and partially close the valve 49, and thereby lessening the supply of steam. At the same time, the rotation of the cam 21 by clock-work continually adjusts the position of the contact 27 and thereby determines the varying temperature at which the capsule 29 engages the contact 27. At the end of the predetermined time, a stop 69, Fig. 3, carried by the cam 21 engages a pivoted lever 60, which is tilted so as to complete an electric circuit through an alarm 68 and also to permit the air pressure in the tank 42 to operate a valve 56 in a casing 55 and to pass by a pipe 71 to a diaphragm 72 controlling a valve 73 which allows a rapid escape of steam from the vulcanizer 13. Simultaneously with these operations. the roller 24 passes into a depression on the cam 21 and allows the spring 32 operating between the levers 15, 25 to move the cam 21 to the left and the projection 15a to the right, the latter movement permitting the air pressure in the pipe 40 to open the valve 35 fully and completely close the steam supply valve 49. The vulcanizer may be fitted with a drain valve 79, and with a sensitive member 82 connected with a temperature recorder 80.