GB982804A - Improvements in or relating to units for supplying air or other gas having a desiredproperty, such as temperature - Google Patents

Abstract

982,804. Ventilation; air heaters. AEROFLOW DYNAMICS Inc. Aug. 3, 1962, No. 29999/62. Headings F4S and F4V. An air or other gas supply unit, particularly an air heating and ventilating unit comprises a casing 11 through which air is blown by a fan (not shown) and is divided into two sets of internal passages 56, 57 separated by horizontal partitions (Fig. 5 being a sectional view turned to the vertical position), winged dampers 64, 65 mounted pivotally at the front edge of the partitions controlling the proportions of the gas flow through the two passages. As shown, alternate passages 57 contain transversely disposed hairpin type steam heating elements 81 which extend from inlet and outlet steam headers at the side of the casing. Each damper includes two curved wings one of which extends into a heating passage 57 and one into an unheated or by-pass passage 56. Single-wing dampers 68, 69 are disposed at the outer edges of the two extreme side passages. Adjacent dampers 64, 65 are arranged to rotate in opposite directions so that restriction of the air flow through one set of passages is accompanied by simultaneous increase in airflow through the other set of passages the convexly-curved form of the damper wings resulting in uniformly low resistance to airflow through the unit at all positions of the dampers. The heating passages 57 are slightly wider than passages 56 to compensate for the presence of the heating elements and the corresponding damper wings are longer than those in the by-pass passages. A motor 101 mounted externally to the casing operates through a mechanical linkage to adjust the positions of the dampers in dependence upon the temperature of the blended air streams as measured by a thermostat control (not shown). The linkage mechanism is arranged so that upon complete closure of the heating passages a switch 131 is closed to operate a second motor 132 which operating through a further system of links closes a set of dampers 90 at the exhaust end of the heating passages. The dampers 90 serve to prevent hot air leaking into the air flowing from the by-pass passages when the heating passages are intended to be completely shut off.