| 摘要 |
1,102,277. Air heaters. SVENSKA FL€KTFABRIKEN A.B. 10 May, 1965 [11 May, 1964], No. 19646/65. Heading F4S. In a tubular heat exchanger in which outdoor air is heated in passing over hot water tubes 2 (arrows A-B), means for preventing freeze-up of the tubes under conditions of low outdoor air temperature comprise a thermostat 5, 6, 7 associated with manoeuvering means (not shown) for either shutting off the outdoor air stream from the heat exchanger, or for mixing room air with the air stream passing to the heat exchanger, the temperature sensing part 5 of the thermostat being located in an active part of the heat exchanger (e.g. the lowest tube 2) close to the water outlet 4. This temperature sensing part 5 is of a diameter such as to ensure that the volumetric flow in the tube portion surrounding said part is less than the flow in the other tubes 2 of the heat exchanger. |
