Patent GB-641767-A (GB)
Title: Improvements in or relating to air conditioning apparatus
IPC: F24F3/04
Filed: 1946-02-13
Abstract: 641,767. Heating and cooling buildings. CARRIER ENGINEERING CO., Ltd. Feb. 13, 1946, No. 15463/48. Convention date, Aug. 12, 1939. Divided out of 641,712. [Classes 64(ii) and 64(iii)] Relates to apparatus for attemperating and ventilating buildings by the circulation of treated air and comprises a central air-conditioning station from which conditioned air is delivered at relatively high pressure and constant rate to a plurality of local units each provided with tempering means to effect as required cooling or heating of the air circulated to the several enclosures in which the units are situated. Flow control means combined with each unit for modulating the flow of heating or cooling medium through a heat exchange device associated with each unit may be a valve. Air is drawn from the outer atmosphere into the casing 25 of a central station conditioning plant by a fan 26 which delivers the air to a distributing main' 27. Air passes into the casing through a filter 28 then over a cooling coil 29 to be subsequently heated by a coil 30 before passing to the main 27. In winter a pre-heating coil 40 receiving steam from the main 36, heats the air so that moisture is absorbed from humidifying sprays 43, the moistened air is then cooled and reheated as before. The steam supply main 36 also heats the coil 30 and the heatexchange coils of the several units. Thermostats 39, 42 control valves 38, 41 controlling the supply of steam to coils 30 and 40 respectively. The coil. 29 is supplied with coolant by a pump 33 from a source 35, a closed expansion tank 50 being connected in the return circuit 32. Pipes 44, 45 are provided for connection to a natural source of coolant in cold weather. Secondary circulation.-Air passes from the distributing main 27 through vertical risers 52, 52<SP>1</SP> to zones A, B respectively, where it is distributed to the units 53 by lateral connections 54, provision being made for reducing the pressure as described in Specification 641,712, [Group X]. A pipe 55 connects the coolant source to a header 56 which supplies each of the local units. A temperature control instrument 57, provided for each zone A, B, is preferably sensitive to air velocity and wind direction as well as temperature. When a need for cooling in the zone is indicated a three-way or proportioning valve 59 is opened so that a pump 60 draws coolant from the header 56 and delivers it through a riser 63 and lateral connections 66 to the units 53, the coolant being returned through a pipe 67. The pumps 60 can also draw coolant through bye-pass line 68 from the return line 67. By varying the proportions of coolant drawn from the header 56 and the return line 67 variation in temperature of the coolant delivered to the units 53 is obtained. Under winter operating conditions the pump 60 draws only from the bye-pass line 68, the liquid then passing to a second proportioning valve 65 through lines 62, 69 in variable proportions. A heater 70 included in line 69 is supplied with steam from the main 36 the supply of steam being modified by a valve 71 connected to the control instrument 57. Crossover pipes 72. 74 are provided so that the direction of flow through pipes 63 and 67 may be reversed under winter operating conditions by adjustment of three-way valves 73, 75. Shut-off valves 76, 77 may be used to isolate the piping of each zone. Cooling coil 29 may be interrupted by shutoff valves 78, 79. A valve 80 is opened to include the expansion tank 50 in the circulating systems. When the local units are controlled manually cross-over pipes 72, 74 and valves 73, 75 are omitted. Local Units (Fig. 2) - Each unit comprises a cabinet 82 having air inlet and outlet grilles 83, 84 and a plenum chamber 85 supplied with air by the lateral connection 54, the supply being controlled by a valve 87, held in the desired position by lock-nuts 90. Sound-absorbing baffles 92 force the air into a circuitous path through the chamber 85 to extension chambers 93, Fig. 4, whence it emerges through nozzles 94 at relatively high velocity into a mixing chamber 95, where it mixes with air flowing in through grille 83. Air is discharged from the chamber 95 past vanes 96 through the outlet grille 84. The vanes may be obtained by punching a solid plate 97 to form apertures 98. Air passing in through grille 83 passes over a heat-exchange coil 99 provided with plate or spiral fins. Liquid from the lateral supply line 66 passes to a twin shut-off valve 100 which also interrupts the return flow through line 101. A control valve 103 described in Specification 641,770, [Group XXIX], is connected to a continuation 107 of supply line 66. Some of the liquid delivered to the valve through continuation 107 is discharged through a pipe 108 to the heat exchange coil 99, the rest of the liquid being returned to the pipe 109 through bye-pass 111. The heat-exchange coil returns the liquid through a connection to the return pipe 109. By manipulating a handle 112 the valve 103 can be regulated to vary the proportions of liquid sent to the heat-exchange coil and the byepass 111, the total supply through pipe 66 and the return connection 101 being maintained at a constant rate. The coil 99 has an air vent 113. Any precipitation from the coil 99 is caught by a drain pan 114 which discharges it to a trough 115, whence it passes by a drain connection 116 to an auxiliary condensate pan 117 and thence to a drain (not shown). An automatic control valve described in Specification 641,770 may place the manually operated control valve 103. This valve is controlled by an element filled with a volatile fluid, such as ether, expanding into a pressure tube in operable relationship with an expansible bellows within the valve. Thermal indicator.-For manual control of the valve 103, a thermal indicator comprising a bulb placed in heat-exchange relation with the supply line 107 and communicating with an expansible bellows is supplied. The bellows carries an indicator plate sliding beneath apertures in the top of the cabinet 82, as described in Specification 641,768, [Group XX]. Pipe joints.-The sections of the riser pipe 52, which may be of galvanized steel, are assembled by providing a belled portion at one end of a section into which is fitted the un-belled end of the above section. A wedging member placed in the belled portion has a circumferential groove above which are vertical slits. To the riser pipes 52 are welded nipples interally recessed to receive flexible conduits 1 secured to tubes to form the lateral connections 54 as described in Specification 641,712. The pipes are enclosed by housings as described in Specification 641,769, [Group X].