Patent GB-445533-A (GB)
Title: Improvements in controlling apparatus for air conditioning systems
IPC: F24F11/00
Filed: 1934-09-07
Abstract: 445,533. Automatic control of temperature and humidity. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Sept. 7, 1934, No. 25785. Convention date, Sept. 8, 1933. [Class 38 (iv)] A device for controlling the atmospheric conditions in an enclosed space has two control means respectively for heat and humidity, by the combination of which a resultant effective temperature or comfort condition is produced. A third control means for predetermining the desired effective temperature is also provided, the three control means being correlated so that adjustment of the third control means brings about any adjustment of the other two necessary to produce the required effective temperature. Also, adjustment of either the heat or humidity control brings about adjustment of the other necessary to maintain a predetermined ratio between them. A humidity responsive device 21, of the kind described in Specification 429,827, [Group XX], consisting of two sets of hairs 24 stretched between supports, operates a movable contact 25 which co-operates with fixed contacts 26, 27 to open or close contact when a predetermined humidity is reached. This hwnidistat is set by a lever 30 pivoted at 31, and forming a pointer 32 on a scale 34 calibrated in per cent of relative humidity. The contacts 25, 26, 27 are connected to a humidifying or de-humidifying apparatus. A thermostat 22 is formed by a bi-metallic strip 36 which carries a contact 39 moving between fixed contacts 40, 41. The thermostat is adjusted by movement of a member 42 and lever 43 having a pointer 44 moving over a scale 46. The contacts 39, 40 and 41 are connected to a heater or cooler for the air which is being conditioned. The levers 30, 43 are connected by an arm 47 pivoted at 481 and having links 48, 49 pivoted at 50, 53 to the levers and at 51, 52 to the arm. The arm 47 is pivoted at 48<1> to a third lever 54 having a pointer 56 moving over a scale 58 which is calibrated in terms of comfort condition or effective temperature. Movement of the pilot lever 54 may by adjustment of the friction at the pivots, be made to operate only the lever 43 while the lever 30 remains stationary, or the lever 30 while the lever 43 remains stationary. By shifting the pivot 48<1> the ratio of the amount of relative movement imparted to the levers 30 and 43 may be altered. Thus, to prevent condensation on cool surfaces, if it be desired to maintain an effective temperature of 64 F., and it is found that the humidity is too high, the lever 30 is moved so that its pointer 32 indicates a lower percentage of relative humidity but by virtue of the linkage the lever 43 of the thermostat is also moved according to the ratio existing between the humidity and dry bulb temperature at the effective temperature. In Fig. 6 is shown a setting for an effective temperature of 76 by moving the pointer 56 and lever 54 to 54<1>, the lever 30 of the humidstat remaining stationary, but the pointer 44 of the thermostat being moved to 82. In Fig. 9, the pivot on which the arm 47 moves is caused to move longitudinally of the arm to vary the ratio of movement between the levers 30 and 43 for each setting if effective temperature. A sliding carriage 67 carries the pivot of arm 47, and flanges 69, 76 support rollers 74, 77 over which runs a chain 78 held at one end by a fixed pin 79 and at the other by the pivot 52. On movement of the lever 54 to the right, i.e. away from the pin 79 the chain causes the carriage 67 to move towards the pivot 52, and changes the distances between the pivot of the lever 47 and the pivots 51, 52 respectively. The effective temperature may be controlled automatically and caused to vary for example during the night and day by clockwork 90 as shown in Fig. 16 in which the clockwork rotates a cam 91 which moves a follower 93 and link 94 attached to the lever 54, the pointer of which indicates the effective temperature.