Fan-blower.

Application filed Tune 19,1909. Serial No. 503,207.

To dll whom it may concern :

Be it known that I, William J. Montgomery, a citizen of of the United States, residing at Jeannette, in the county of West5 moreland and State of Pennsylvania, have invented certain new and useful Improvements in Fan-Blowers, of which the following is a specification, reference being had therein to the accompanying drawing.

. This invention relates to fans and has as its object to provide a fan particularly adapted for the work of mine ventilation and is constructed so as to secure a maximum of efficiency combined with the quali15 ties of mechanical simplicity and durability.

Figure 1 is a perspective view of a fan embodying my improvements. Fig. 2 is another perspective view showing the fan as seen from the side opposite that shown in 20 Fig. 1. Fig. 3 is a view of one of the blades as it is shaped when in assembled position. Fig. 4 is a vertical section of the fan through the axis of the shaft.

The fan shaft 1 is mounted in bearings 25 formed in the upper end of the standards 2, 2, which are bolted to the base plate 3. The driving hub 4 is keyed to the fan shaft and is formed with a radially extending flange 5 to which is bolted the disk ΐ which fits ' ³⁰ snugly around the fan shaft.

The fan blades 8 are each formed from generally rectangular blanks provided at their inner ends with flanges 9, 9 extending in opposite directions in the plane of the ³⁵ fan at an angle of approximately 60° to the plane of the fan. The blades when fastened in place form acute angles with the plane of the fan. The flanges upon corresponding edges of the blades are riveted to 40 the disk 7, and the flanges formed upon the opposite edges of the blades are riveted to the sheet metal ring 10, the greater diameter of which is the same as the diameter of the disk 7. The inner circumference of the 45 ring approximately coincides with the circle of the inner edges of the blades, and the width of the ring is about equal to the length of one of the flanges 9. The ring is entirely unsupported, except by the blades 8, ⁵⁰ and has no mechanical connection with the shaft 3 in any other manner. The blades extend outwardly from the peripheries of the disk 7 and ring 10 to a point within close proximity to the surrounding station55 ary circular casing 6, which is rigidly mounted upon the base plate 1 and is shown in the drawings as formed from a single steel band.

The rear outer corner of each blade is connected to the forward outer corner of 60 the blade next behind it by means of an adjustable stay rod 11. By means of these stay rods the blades can be twisted until they assume a warped or spiral shape, and this distortion can be so magnified that the 65 perpendicular distance between adjacent blades is approximately the same at any 1'adial distance from the center of the fan.

The number of blades is so proportioned to the size of the fan and the angular rela- 70 “θη °f the .plane the blade to the plane XL 11 , ⁿ i^{s sucp} the radial edges of the blades overlap each other slightly and the stay rods 11 are disposed substantially perpendicular to the planes of the blades. 75 this overlap is produced in part bv the somewhat tapering shape of the blade'from its inner and narrower to its outer and wider edge.

This fan is adapted to drive air from it 80 along lines perpendicular to the plane of its circumference. In such fans difficulty has been· heretofore experienced because of the reentry of the air within the fan spaces at the center of the exit side of the fan. The 85 disk 7, by means of which the blades are supported, effectually prevents any such back current of air.

The. air is drawn toward the fan upon its inlet side at all points within the area of the 90 fan circle, excepting, of course, the area occupied by the ring 10 and the shaft 1. Air is drawn into the air spaces between the ring 10 and the fan shaft, is then given a centrifugal motion by the suction action of 95 the fan blades, and is lastly deflected along lines at right angles to the plane of the fan and discharged. By thus utilizing the central parts of the inlet side of the fan, the pressure of which the fan is capable is 100 greatly augmented and the presence of the disk 7 is prevented from interfering with the capacity of the fan. Air is also received by the fan blades upon the inlet side at points between the ring 10 and the casing 105 6, Undesirable centrifugal action of the fan blades near their outer ends is prevented by .causing the blades to assume the twisted spiral shape, already described, and it has been found by experiment that when 110

1,136,827 the blades are so constructed the air is driven forward from the fan at approximately the same velocity at all radial distances, in spite of the greatly varying linear velocity of the 6 different portions of the blade, corresponding to the radial distance of such portions from the fan shaft.

The disk 7 should have at least one-fifth the diameter of the fan as a whole, and it 10 has been found by experiment that when the diameter of this disk is about one-half, the efficiency of the fan is at a maximum.