Title:
Fan and fan blade
United States Patent 2079044


Abstract:
This invention relates to motor driven fans and Particularly to propeller fans wherein the blade construction Is based on the airfoil principle, that is, where the blade has a streamline body whose maximum thickness is located approximately one third the distance from the leading edge and recedes...



Inventors:
Santmyer, Lewis B.
Application Number:
US63220432A
Publication Date:
05/04/1937
Filing Date:
09/08/1932
Assignee:
Joseph, Beck A.
Primary Class:
Other Classes:
415/106
International Classes:
F04D29/32
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Description:

This invention relates to motor driven fans and Particularly to propeller fans wherein the blade construction Is based on the airfoil principle, that is, where the blade has a streamline body whose maximum thickness is located approximately one third the distance from the leading edge and recedes from the maximum thickness to both the leading and trailing edges.

An object of this invention is the provision of a fan having a blade structure Provided with only one cutting edge and one trailing edge.

Another objectIs the provision of a blade for fans, so arranged that it has but one cutting edge and one trailing edge within the circle defined by the tip of the blade when rotating.

Another object is to increase the eficiency of a fan by the use of but a single blade.

The herein disclosed embodiment illustrates a Practical means of reducing the invention to practice. In the drawing: Figure 1 is a front elevation of a fan assembly embodying the invention.

" Figure 2 is a side elevation thereof with the support annulus in section.

Figure 3 is a front elevation of an alternative form of blade. * Figure 4 Is a section through the blade of Fig.

1 at a right angle to Its radial axis.

Figure 5 is a section through the counterweight at a right angle to its' adtlal axis.

For purposes of illustration the fan is shown as an assembled ventilatop unit consisting of a Ssupport annulus 10 apertured as at I Ilto recelve securing elements by which it is fastened in a wall or other support, and carrying an attached frame made up of a cross-piece 12 and a central brace 13. t The fan motor 14 is attached to the frame 40 15 extends axially through the annulus 1. a Mounted on the motor shaft is a single airfoil c blade 18 having a cutting edge 17 and a trail- c ing edge 18 which meet at the blade tip Is. The r blade is so disposed on the motor shaft that its r tip 19 occupies the plane of the annulus, being a spaced slightly inwardly therefrom. At Its hub a the blade IS is provided with a streamlined coun- t terweight portion 20.

. In the alternative embodiment shown in Fig- pue 3 the blade 16' is shaped'substantially as a Paddle with a relatively long curved cutting edge urv' and asimilarly curved trailing edge 18' and fo curved tip 19'. This blade is also provided With \ Sa streamlined counterweight portion 20'. t -The particular shape of blade is Immaterial so Ul long as there is but one cutting edge and but one trailing edge within the circle defined by the bladede when in rotation.

Numerous tests have been conducted with two types of twenty six inch fans, one the conven- 6 tional two blade type with two cutting edges and typ e made by taking the identica conventional two blade type removing one of the blades and properly counterbalancing to form same into a single blade, with one cutting edge and one trailing edge in accordance with my invention, the diameter of the fan circle being the same.

Tests for H. P. input and air delivery were taken and showed that the same H. P. consumed in driving the two blade fan would drive a single blade fan and produce about one-third more cubic feet of air.

The two blade type fan produced approximately thirty-five per cent more cubic feet of air than the single blade fan but required about one hundred and ten per cent increase in H. P. nput to Produce this additional thirty-five per cent cubic feet of air.

By the practice of this invention a material reduction in operating cost is made possible and efficiency is increased. The single blade is adapted to replace multiple blade units merely by substitution on thefan motor shaft or spindle.

I claim: 1. A rotary fan blade having only one cutting 30 edge and one trailing edge in a circle defined by the blade tip when the blade is rotating.

2. In a fan, a rotatable unit, and a single blade attached to said unit for rotation therewith, said )lade having only one cutting edge and only one railing edge within the area defined by the tip )f the blade when in rotation.

3. A fan comprising a support, a motor carried hereby, a shaft driven from said motor, and An airfoil blade on said shaft presenting only one 40 utting edge and one trailing edge within the lrcle defined by the tip of the blade when in otation.

4. A fan, blade comprising an airfoil section nd counterweight having a total length slight- 45 r greater than the radius of a circle defined by he tip of the blade when rotating.

5. In a fan;a driven shaft, a single Integral onelece blade and counter-weight mounted theren to turn therewith .50 6. In a fan, a blade and a counter-weight therer, said counter-weight being streamlined.

7. A fr.n blade and a counter-Weight integral Lere'With, said counter-weight being stream- 65 8. In a fan, a driven shaft, and a single airfoil blade on said shaft and perpendicular thereto, said blade being entirely airfoil in a dimension coextenrsive with the radius of a circle defined by the tip of the blade when rotating, and a streamlined counterweight beyond its airfoil portion, the total length of said airfoil portion and counterweight being only slightly greater than the radius of a circle defined by the tip o10 of the blade when rotating.

9. In a fan, a motor, a shaft driven from said motor, a single blade mounted on said shaft, said blade having but one leading edge and but one trailing edge within a circle defined by the tip of the blade when rotating, and a counterweight 6 therefor, said counterweight being streamlined.

LEWIS B. SANTMYER.