Patent GB-102156-A (GB)
Title: Improvements in and relating to Apparatus for Regulating Humidifying and Heating Systems.
Inventor: THOMPSON ALBERT WILLIAM
IPC: F24F3/14
Filed: 1916-11-08
Abstract: 102,156. Thompson, A. W., and Comfort, E. W. Nov. 10. 1915, [Convention date] Hygrometric apparatus. - Relates to hygrometric apparatus of the wet and dry bulb type for controlling automatically the humidity of the temperature of the air in a room. Two expansible members with equal coefficients of expansion are exposed, the one to the dry-bulb temperature, and the other to the wet-bulb temperature of the atmosphere of the room, and tile differential expansion of the two members is adapted to control a source of energy for effecting the supply of moisture or heat to the room. The apparatus is mounted in a closed casing divided, as shown in Fig. 1, into communicating compartments 3, 4, 5, containing respectivelv the wet-bulb device, the dry-bulb device, and indicating and transmitting mechanism. The expansible members of the wet and dry bulb devices respectively are a hollow cylinder 14, preferably of ebonite, seated on a bracket 16, and a similar cylinder 17 seated on a bracket 19. The upper ends of the cylinders 14, 17 are internally threaded to receive the externally threaded heads 27, 28 of rods 25, 26 of invar steel or like non-expansible material. The lower ends of the rods 25, 26 are connected by leaf springs 23, 24 to the arms 21, 22 respectively of a lever 20 of inverted-T shape, and the upper end of this lever is adapted to bear through a screw 29 on a spring-controlled lever 31 arranged to control the outlet from a compressed-air conduit 35. To permit of vertical movement of the lever 20 when the wet and dry bulb devices expand or contract together, its lower end is connected to the casing by an horizontal link. To enable the effective length of the dry-bulb member 17 to be varied, the head 28 is mounted on the rod 26, as shown in Fig. 3, by forming on the the rod 26 a screw-thread of the same pitch as that in the interior of the member 17. The adjustment is effected by rotating a knob 42 attached to a member 38 mounted in a bracket 39. and fitted with rods 43, 44 extending through holes in the head 28. The member 17 is slotted longitudinally and is graduated, as shown in Fig. 1, to indicate the position of adjustment. Air from the room enters the apparatus by an inlet 12 at the base of the compartment 5 and passes out through a conduit 13 at the top of the compartment 3. To maintain the member 14 at the wet-bulb temperature, it is covered with a mantle of filter-paper, muslin, or like material which receives water supplies froma sprayer 50 discharging into the conduit 13. The water passes through a filtering-annulus 58 to a trough 57, and thence by a tube or rod 59 to the mantle. To indicate the wet and dry bulb temperatures, two thermometers are mounted on the doors of the casing with the bulbs within the casing adjacent to respectively the cylinder 14 and to the cylinder 17, the wet bulb having a covering of absorbent material. The valve (not shown) for regulating the supply of moisture or heat to the room is normally closed by compressed air supplied to a conduit 94, 95 through a relay valve 87, Fig. 5, which is normally held open against a spring 91 by compressed air introduced into a chamber 65 behind a diaphragm 70. The compressed air is supplied through a pipe 72, Figs. 1 and 4, to a chamber 73 filled with filtering-material 76, and the filtered air passes by a pipe 82, to the valve 87, and by a pipe 69 to the chamber 65, with which the conduit 35 also communicates. Upon operation of the lever 20 to release air from the conduit 35, the diaphragm 70 is moved away from the stem 86 of the valve 87, allowing the valve to be closed by the spring 91 and allowing air to escape through hollow stem 86 from the conduit 94, whereupon the main regulating-valve is opened to supply moisture or heat to the room until the lever 20 is moved to its former position, allowing the diaphragm 70 again to open the valve 87. A sensitive action of the diaphragm is obtained by providing a restricted passage 78, Fig. 4, between the chamber 73 and the pipe 69.