GB344914A - Improvements relating to the ventilation of enclosures - Google Patents

Abstract

344,914. Ventilating enclosures. CARRIER ENGINEERING CO., Ltd. and SAINTY, C. L., 24, Bucking- ham Gate, London. Dec. 9, 1929, No. 37718. [Class 137.] Relates to methods of controlling a ventilating air stream of sensibly constant density. Where a main air stream supplies a number of enclosures means are provided for maintaining constant the difference between atmospheric pressure and the total or static pressure in the main duct irrespective of variations in the amounts of air taken by the individual enclosures. In the case of a single stream the quantity and velocity of the air supplied are maintained constant. As shown in Fig. 1, a fan 1 draws fresh air from an inlet 2 past a conditioning device 3 or past a heater 3b and air for recirculation from a duct 4 and delivers the mixture to a series of enclosures 8, 9, 10 through a main duct 6 and secondary ducts 7. Air is withdrawn from the enclosures by a fan 11 through a main duct 12 and secondary ducts 13. Manually or automatically adjusted dampers 15, 16 regulate the air supply to the individual enclosures and may be so arranged that atmospheric pressure or a pressure slightly above atmospheric is maintained. In a modification the recirculation duct 4 is omitted. In order that an alteration in a damper 15 of one enclosure may not affect the air supply to the remaining enclosures, a pressure regulator 20 responsive to the total or to the static pressure is fitted within the main duct 6 and actuates a damper 24 to maintain constant the difference between the said duct pressure and the pressure of the still atmosphere. A similar control system may be located in the main extraction duct 12. The regulator 20 is connected to the inside of a bellows forming a diaphragm valve 21, the exterior surface of the bellows being exposed to atmospheric pressure. Any change in the pressure difference allows more or less compressed air from a supply 22 to pass to an air lever motor 23 operating the damper 24. For maintaining a constant supply in a duct, the regulator is responsive to pressures at different points and operates differentially to vary the resistance such as a damper 40, Fig. 6. As shown in Fig. 7 the regulator is responsive to the difference between the static and total pressures of the air stream.