US1066988A - Propeller. - Google Patents

Description

W. R. BOUTWELL. PROPELLER.

APPLICATION FILED 11.4, 1912.

1,066,988, Patented July 8, 1913.

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WILLIAM R. BOUTWELL, 0F NORFOIlK, VIRGINIA.

PROPELLEB.

Specification of Letters Patent.

Application filed April 4, 1912. Serial No. 688,562.

To all whom it may concern:

Be it known that I, WILLIAM R. BourwELL, a citizen of the United States, residin at Norfolk, in the county of Norfolk an State of Virginia, have invented new and useful Improvements in Propellers, of which the following is a specification.

My invention. relates to propellers, and more especially to screw propellers used for driving ships and other water craft as well as air ships, my more particular purpose being to lessen or alleviate the trouble due to back ressure against the front faces of the propefier blades and the slug ish centering of the medium around the hu owing to. the back wash of the water or air as the vessel moves forward.

More particularly stated my invention comprehends a propeller so formed as to cause water or air as the case may be, to flow through the propeller blade at points located ad acent to the forward or cutting edge thereof-this water or air flowing in such direction as to meet the back wash and to divert the same, causing it to be discharged between consecutive blades of the pro eller.

y invention further relates to the provision of means associated with each propeller blade, for diverting the backwash of water or air from the front faces of the blades and thereby preventing to a great extent the objectionable vortex which obtains about the hub and lower part of the propeller blades.

I have made-the discovery that with most propeller blades of simple construction, when used for driving a vessel forward through the water, there is apt to develop considerable ressure against the front faces of the propeller blades due towater known as back wash, and this causes a substantial retardation in the forward movement of the vessel. I have also made the discovery that it is practicable to divert the flow of the back wash to some extent and cause the same to be discharged from the front face of the blade in such manner as to offers. minimum of resistance to the forward movement of the vessel and without impinging of the openings above referred to and disposed adjacent to the operative or cutting edge of the blade of the propeller; and also by adding upon the propeller blade, :1 second blade having preferably a form hereinafter described, this second blade being so located that when the propeller turns, the second blade causes an outward and upward flow of water adjacent to the front face of the propeller blade, thereby reducing to a minimum the vortex at the hub.

Reference is made to the accompanying drawing forming a part of this specification in which like letters indicate like parts.

Figure 1 a fragmentary elevation of a screw propeller, the front face thereof being the one viewed by the observer. 'Fig. 2 is a section on the line 2-2 of Fig. 1 and showing the'propeller as it would be seen by an observer standing beyond the same according to Fig. 1 and looking downward. Fig. 3 is-a diagram illustrating the effect of back wash against the forward or front face of an ordinary propeller blade of simple construction. Fig. 4 is a diagram show ing how the openings in the propeller blade are used, in my invention, for diverting the flow of the back wash from the front face of the propeller blade.

The propeller hub is shown at 5, and carries a number of propeller blades 6 which as here shown are of simple construction. Each propeller blade is provided with openings 7, in this instance circular holes, dis posed adjacent to one edge 8, this being the forward or cutting edge of the blade as the propeller is turned in a suitable direction to drive the vessel ahead. The row of holes or openings 7 has generally the proximate curvature of the adjacent edge 8 of the propeller blade. A deflecting blade 9, having generally the form of a half lune, is

provided with a flange 10 integral with it and of arcuate fOlll'l llllS flange being secured by fastenings 11 directly upon the front face of the propeller blade. The half lune deflecting blade 9 may be cast integral with the propeller blade, or may be secured to it in any suitable and desirable manner. The deflecting blade 9 when brought into the position indicated in Fig. 1, and seen by an observer looking strai ht down upon it has, in appearance, a su stantially trian- Patented July 8, 1913.

gular form as will be understood from Fig.

' -a little water to. flow from the rear of each' curvature, being convex upon its outer" face and concave upon its inner face, as .will be understood from Fig. 1. I

According to Fig. 1 the propeller is turning in a clockwise direction. According to Fig. 2 the propeller blade shown in section is moving toward the left.

A general idea of the purpose of this invention and of the manner in which it overcomes the difiiculties above suggested may be obtained by analysis of Figs. 3 and 4. Fig.

3 shows a propeller blade of ordinary construction, as the blade would be seen by an observer standing at the rear of the .propeller and looking downwardly upon the blade, the latter, in this instance, belng supposed to turn toward the left. The primar discharge of. the water or air by the bla e in consequenceof its rotation, is to the rear of the blade. The rotary motion of the blade and the discharge of water or air thereby causes a flow of water or air against the front face of the blade as indicated by the large arrow in Fig. 3. This flow of water or air is what I designate as back wash, and which I desire to divert'in orderto alleviate or reduce the resistance due to forward movements'of the vessel.

Referring to Fig. 4, the effect of providing the openings 7 W111 be observed. The primary tendency of these openings is to admit propeller blade to the front thereof as indicated by the small arrow at the extreme 'left of Fig. 4. The small arrows indicate the courseof this water or air. The water or air thus passing through the openings 7 is met by the Water or'air of the back Wash, and tends to divert the flowof the back wash, as. indicated by the series of large arrows-in Fig. 4. That is to say, a little water or air from the rear of the propeller blades, after passing through the openings 7, mixes with the back wash, and the entire volume of water or air making up this admixture now flows substantially midway beblades.

tween two consecutive propeller blades, as indicated in Fi 4.. It is important, in diverting the bee wash-from the front face of a propeller blade, not to divert the back wash against the next consecutive propeller blade, butrather to have themixture of the back wash, and water=for diverting the same, flow as a unitary stream between consecutive It is true that the volume of water or air comprising back wash is much greater than volume of water or air assing through the openings is sufiicient to ivert theback wash to aslight extent, and this is allthat is nec-' essary in order to prodnce a subtial rewardly from the center of rotation, and con-.

Tovercoming the tendency to pocket around the hub. i

1,oee,ese

lief from the "pressure due to the back wash against the front face of the propeller blade. The deflecting blades 9 are very useful in coacting withthe openings for the purpose of causing the back wash to be removed from the front face of the propeller blade. The curvature of each deflecting. blade 9 is such that, when theblade is turning, the volume of water or air flowing against the front or-forward face of'the bladeis pushed outsequentlylis discharged as nearly as practicable from the outer end of the blade rather than from ortions thereof adjacent to the hub. This is of material advantage, as the action of the deflecting blade 9, by removing a portion of the back wash, tends to prevent the back pressure due to-the back wash from retarding the general forward movement of the propeller through the water, as'well as It appears that the openings 7, in order to have their greatest efiiciency, should be preferably located near the periphery of the propeller blade. If locatedtoo far inward from the edges of the blade, the, water or air admitted through the openings does not effectively divert the flow of the back wash as above described. The shape-of the openings is a matter of minor importance and the angle at-which the openings extend through the blade ma be varied according to circumstances. Or inarily, the openings may have the form of plain round holes extending at right angles directly through the 'ler. Not only does the peripheraldischarge avoid hubbing, but it also avoids undue pressure due to back wash against the front faces of the blades, even at considerable distances outwardly from the hub. The deflecting blade 9 also tends to prevent hubbing as well as to deflect the back wash which otherwise tends" to make back presslfi'e against the pro-.

peller blade. The peripheral discharge due in) the openings 7 and the flowof water or air due to movements of the deflecting blade 9, therefore, coact together to produce, the 125 common object of diverting the back wash I from the front facesof the propeller blades and the sluggish water around the h b. M j

I do not'limit myself to the precise construction shown, nor to the use of my device .180

in any particular fluid medium, though I have in mind more particularly a propeller suitable for use in either water or air.

I claim,

1. In a propeller, the combination of a propeller blade having a number of perforations near its forward edge adapted to admit therethrough a small portion of the fluid propelled, said perforations being disposed at an angle directing the fluid against the back wash whereby to direct the latter between two adjacent propeller blades, and a diverting blade mounted upon the front face of said propeller blade and having one end located nearer the center of rotation than the opposite end thereof whereby to divert outwardly the flow of back wash against the front face of the propeller blade.

2. In a. propeller, the combination of a propeller blade and a diverting blade mounted upon the front face of said propeller blade, the forward end of said diverting blade being located nearer the center of &

rotation than the opposite end thereof whereby the flow of back wash against the front face of said propeller blade is diverted outwardly.

3. In a propeller, the combination of a revoluble propeller blade and a diverting blade mounted upon the front face of said propeller blade, said diverting blade being wider at one of its ends than at its opposite end, the wide end of said diverting blade being farther than the narrow end thereof from the center of rotation in order to divert outwardly the flow of back wash otherwise tending to press against the adjacent face of said propeller blade.

In testimony whereof I haw hereunto set my hand in presence of two subscribing witnesses.

\VILLIAM R. BOUTVVELL.

\Vitnesses JAs. R. PEAKE, JOHN D. WATSON.

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