GB902738A - Improvements in or relating to air conditioning systems - Google Patents

Abstract

902,738. Unit and valve apparatus for ventilating. INTERNATIONAL ANEMOSTAT HOLDING CO. Ltd. Jan. 27, 1961 [Jan. 27, 1960], No. 3222/61. Class 137. Relates to a ventilating duct including a pivoted valve moved towards closed position by an increase in the static upstream air pressure, the movement being lower for a change of pressure at higher pressures than for a change of pressure at lower pressures so that the rate of air flow is kept constant. According to the invention, the reduction in passage area in the duct due solely to movement of the valve with increasing pressure is not great enough and the valve co-operates with an orificed plate, the orifices in which are so dimensioned that they are closed at a higher rate by the valve at low pressures than they are at higher pressures. The Specification also describes admission valves for hot and cold air, all the valves being embodied in unit apparatus. Unit apparatus (Fig. 1).-Hot and cold air under pressure can enter a mixing chamber 30 through inlets 26, 28 controlled by flap valves 48, 50 operated in antiphase by a thermal element in the room. The valves have on their surfaces which are swept by the air fins 74 which are oppositely inclined so that the hot and cold air streams are caused to swirl anticlockwise and clockwise at the front and back respectively of chamber 30 before finally mixing. The valves are mounted on holders 52 so that they can be interchanged to swirl the two streams in the opposite directions. The mixed air then passes from chamber 30 into upper chamber 38 through constant flow valve 36 and then passes into the room through top aperture 46. Chamber 38 and a baffle plate 42 are lined and covered with sound-deadening material 40. Hot and cold air valves (Fig. 1).-Valve holders 50 are pivoted at 56 in chamber 30 and their free ends are pivoted at 60 to links 108, 110 connected at a common point 112 to one arm 88 of a bell-crank 96. This is swung about its pivot 90 by a pneumatic cylinder 114 and connecting rod 102, the cylinder being controlled by a thermostat in the room. Rod 102 can be connected to the bell-crank either at 104 or at 106 so that the hot and cold supplies 26, 28 can be reversed. Constant flow valve 36 (Figs. 6 and 7).-This comprises a rectangular duct 132 having an inlet defined by a flange 142 and gasket 144. A flap valve 146 has lateral pins 152, 154 working in bearings 160, 162 and an outward extension of pin 152 carries a crank 170, the outer end of which is connected to a tension spring 168 at 172. When the valve is fully open as shown, pin 152, connection 172 and the anchorage 178 of the spring are nearly in line so that a relatively small increase in upstream air pressure will allow a relatively large movement of the valve towards duct closing position. At higher pressures, however, the valve being already partially closed, a rise in pressure will only move the valve a relatively small amount because crank 170 will lie at a substantial angle to the spring axis. This differential effect is, however, insufficient and an arcuate plate 194 spans the duct and has apertures 198 progressively closed by movement of the valve. As shown, apertures 198 are relatively large at the parts 200 first occluded by the closing valve and relatively small at the parts 204 last occluded by the closing valve. A transverse extension 196 of plate 194 has permanently open apertures 206.