| 摘要 |
<p>808,900. Automatic temperature control. S.A.F.F.A. SOC. P.A. FABRICHE FIAMMIFERI ED AFFINI. June 3, 1955 [July 12, 1954], No. 22684/57. Divided out of 808,899, ]Group VIII]. Class 38 (4). In a system for controlling the temperature of the rollers of a machine for the continuous production of relief pattern packing paper wherein the rollers are heated by electrical resistances, control is effected by three thermocouples fitted to the rollers, one controlling the temperature limit and the other two maintaining the temperature difference within predetermined limits. The heaters 2, Fig. 4, which are within the rollers 1 and are evenly spaced around the periphery are " star " connected to a three-phase supply through slip-rings on the shaft and the temperature of the rollers is detected by a thermocouple 39, the end of which is inserted into a groove between a pair of discs 3, 3<SP>1</SP>. The heater resistances 2, 2<SP>1</SP> are connected to the mains through the contacts 18, 18<SP>1</SP>, Fig. 1, of relays 16, 16<SP>1</SP> and both relays are released when the output of thermocouple 12 opens contact 15 of a contact voltmeter 11 in response to the rollers reaching the temperature determined by the setting of a trip arm 10. Thermocouples 20, 21 which are connected in series opposition control, by the sign and magnitude of their difference of output, the arm 22 of electromagnetic apparatus 23 to tilt a mercury switch 27 in the appropriate direction. Relay 16 or 16<SP>1</SP> is thus operated to interrupt the current supply to the hottest roller when the temperature difference exceeds the limit set by feelers 25, 26. The expansion of mercury in a bulb 30 which is coupled to roller 1<SP>1</SP> by a roller 31 is arranged to control the speed of the pattern rollers in proportion to their temperature through a piston 34 in a cylinder 33, and a cam 36 which regulates a governor through a lever 37. The speed control may alternatively be effected electrically or electronically.</p> |
