| 摘要 |
<p>Cooling apparatus comprises a cooling chamber such as a freezing tunnel 2 having a pipeline 4 for introducing liquid nitrogen into it and an exhaust passage 14 for cold nitrogen vapour. The exhaust passage 14 extends through a rotary regenerative heat exchanger 20. Downstream of the heat exchanger 20 is a fan 26 operable to draw the exhaust gas through the heat exchanger 20. A second passage 28 extends through the heat exchanger 20 and is arranged for the flow therethrough of relatively warm air, whereby, in operation, the air is able to transfer heat to the exhaust gas in the heat exchanger 20. <IMAGE></p> |
