| 摘要 |
1,006,549. Centrifugal fans. P. LEROY, and B. CHANTEMERLE. June 8, 1962 [June 14, 1961], No. 22222/62. Heading F1C. [Also in Divisions F4, H2 and H5] An electrically-driven centrifugal fan-heater comprises a casing having a shape the outline of which is substantially that of a spiral in the first two quadrants of rotation of the fan and, in the third quadrant, an oblique straight line forming an obtuse angle with that wall of the casing which is furthest from the axis of the fan, the wall being substantially parallel to the axis of a discharge opening of the fan-heater. Fig. 1 shows the new fan casing in full lines, a conventional fan casing being shown in broken lines for comparison. Whereas the straight wall 6 flanking the discharge opening of the conventional casing and substantially parallel to the axis of the discharge opening is connected directly to the spiral wall of the casing, the corresponding wall 10 of the new casing is connected to the spiral wall through a substantially straight wall 12 tangential to the spiral and forming an obtuse angle with the wall 10. As shown, the junction between the walls 10 and 12 may be rounded off. The casing is formed from two sheet metal pressings joined together at flanges 16, Figs. 2 and 3, in a medium plane transverse to the impeller axis. Heater elements 22, held by supports 21 of steatite or other refractory insulating material, are disposed between each of several parallel plates 19, the heater assembly being carried by a metal frame 18 which is a detachable push fit in the discharge opening. A voltage adjusting panel 33 (see Division H2), mounted by means of straps 31 in a cut-out 30 in the casing flanges, enables two halves of the heater elements, and two halves of the motor winding, to be connected either in series or parallel to suit the supply voltage. A thermostat is provided with an adjusting knob 24. The assembly may be mounted in a box 53, Fig. 7, provided with slots 55 for the flow of air to the inlet opening 26. |
