| 摘要 |
<p>1,000,549. Thermo-electric devices. YORK SHIPLEY Ltd. Nov. 13, 1962 [Nov. 24, 1961], No. 42963/62. Heading H1K. A thermo-electric couple normally supplied with rectified alternating current, for cooling purposes, may be coupled directly to an alternating current supply when it is desired to heat the device. The thermo-couple 23 is in heat-exchange relation with a heat-conducting element 25 on which is placed a container 26 to receive objects to be refrigerated. Uni-directional current, to effect the desired cooling, is obtained from the secondary winding 12 of transformer 10 through rectifiers 15, 16 and a centre-tap lead 17, and ripple is removed by a choke 21. When it is desired to heat the unit, for defrosting, a switch arm 30 is moved from contact 29 to contact 28 so that alternating current, through a further lead 27, is passed directly through the thermocouple. This, acting merely as a resistance, consequently becomes heated. Arcing at the contact 29, which would arise from the inductance of the coil 21, is avoided by a short-circuiting rectifier 22.</p> |
