| 摘要 |
<p>808,022. Automatic temperature control systems. KELVIN & HUGHES Ltd. April 20, 1956 [Feb. 18, 1955], No. 4928/55. Class 38 (4). [Also in Group XL (c)] In an automatic temperature control system, an unspecified device detects temperature deviations and controls intermittently either a heater or a cooler as appropriate, there being a time delay before either the heater or the cooler is energized. The device 11 has a movable contact 12 which is stated to oscillate between contacts 13, 14, the proportions of each cycle during which the contacts 13, 14 are energized depending upon the sense and magnitude of the temperature error. Whilst a contact, e.g. 13, is energized, its associated valve 24 is cut-off by negative bias from rectifier 43 applied to the suppressor grid, and the " heater " relay 16 is de-energized. The valve 24 is connected as a Miller integrator so that as soon as contact 13 opens, the anode current rises, until after a predetermined time-delay the relay 16 is energized to actuate an undisclosed heater. Relay 17 actuating an undisclosed cooling device is similarly controlled. When the temperature is correct, contacts 13, 14 are each energized for half the cycle of the device 11. The time delay introduced by the integrators is preferably made equal to this half-cycle so that under correct conditions neither relay has time to be energized, and the appropriate relay is energized for periods proportional to any deviation. In a second embodiment, the time delay is effected by a thermistor in series with each relay.</p> |
