Abstract 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.
IN A TUBULAR HEAT EXCHANGER FOR HEATING OUTDOOR AIR HAVING A LEAST ONE TUBE CONNECTED AT ONE END TO A REMOTE SORUCE SUPPLYING HEATED WATER AND AT THE OTHER END TO A RETURN PIPE, AND INLET FOR INTRODUCING OUTSIDE AIR TO SAID HEAT EXCHANGER AND AN OUTLET FOR DISCHARGING THE HEATED OUTDOOR AIR FROM SAID HEAT EXCHANGER, SAID INLET HAVING CONTROL MEANS FOR REDUCING THE COOLING EFFECT OF OUTDOOR AIR UPON THE WATER FLOWING THROUGH SAID TUBE; THE IMPROVEMENT COMPRISING AN ANTIFREEZE THREMOSTAT FOR OPERATING SAID CONTROL MEANS INCLUDING A SENSING BODY IN SAID TUBE IN THE FLOW PATH OF THE WATER CLOSE TO AND UPSTREAM OF THE WATER RETURN PIPE.
Claim 2
Dependent Claim
111 words
IN A TUBULAR HEAT EXCHANGER FOR HEATING OUTDOOR AIR HAVING A LEAST ONE TUBE CONNECTED AT ONE END TO A REMOTE SORUCE SUPPLYING HEATED WATER AND AT THE OTHER END TO A RETURN PIPE, AND INLET FOR INTRODUCING OUTSIDE AIR TO SAID HEAT EXCHANGER AND AN OUTLET FOR DISCHARGING THE HEATED OUTDOOR AIR FROM SAID HEAT EXCHANGER, SAID INLET HAVING CONTROL MEANS FOR REDUCING THE COOLING EFFECT OF OUTDOOR AIR UPON THE WATER FLOWING THROUGH SAID TUBE; THE IMPROVEMENT COMPRISING AN ANTIFREEZE THREMOSTAT FOR OPERATING SAID CONTROL MEANS INCLUDING A SENSING BODY IN SAID TUBE IN THE FLOW PATH OF THE WATER CLOSE TO AND UPSTREAM OF THE WATER RETURN PIPE.