US2149155A

US2149155A - Propelling device for ships

Info

Publication number: US2149155A
Application number: US204134A
Authority: US
Inventors: Albert F Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-04-25
Filing date: 1938-04-25
Publication date: 1939-02-28
Anticipated expiration: 1956-02-28

Description

Feb. 28, 1939. I N N 2,149,155

PROPELLING DEVICE FOR SHIPS Filed April 25, 1938 3 Sheets-Sheet 2 FIGURE 6 FIGURE 8 AF? Anderson INVENTOR.

BY WWW ATTORNEY.

Feb. 28, 1939. A. F. ANDERSON PROPELLING DEVICE FOR SHIPS Filed April 25, 1938 S Sheets-Sheet 3 Q mmbwbl AFTAnderson INVENTOK ATTORNEY.

Patented Feb. 28, 1939 UNITED STATES PATENT OFFICE 'lClaims.

This invention relates to improvements in ships propellers of the type employing a thrust casin having a passageway or conduit extending entirely through it in the direction of travel and in which is positioned an impeller which operates to produce a flow of water or other fluid through it and to expel the same at the discharge end at an increased velocity.

This invention relates more particularly to an improvement in the propeller shown and described in U. S. Letters Patent No. 2,112,948, granted to me on April 5, 1938.

It is well known that the resistance which a body offers to movement through water or air can be greatly modified by its shape and bodies which are shaped to offer the least resistance are said to be streamlined.

It is an object of this invention to produce a propeller thrust casing designed to offer a mini- 90 mum of resistance to movement through a fluid.

In propellers of the type here under consideration, a thrust casing is attached to the hull of the vessel to be propelled, usually to the bottom of a ship and in any other suitable position on an airship. The casing is provided with a passageway extending in the general direction of ship travel, and through which the water or air is flowed under the action of an impeller positioned therein, the cross sectional area of the passage:

way being greatest at the inlet and decreasing progressively towards the discharge opening, the ratio of the areas of the intake and the discharge openings being preferably 2 to 1. Since the same quantity of water flows past any given transverse plane in the same time, itis evident that the velocity at the discharge is twice that at the intake and the passageway is so designed that the increase in velocity is attained by continuous positive acceleration.

The efiicie'ncy of a propeller of the type here under consideration is dependent, to a great extent, on the type of impeller used and on the position of the impeller, relative to the flow of fluid. It is also desirable to employ a construction in which the impeller is not subjected to any thrust in the direction of its axis of rotation, as it is in screw propellers. By avoiding end thrust, thrust bearings can'be dispensed with.

It has been found that by positioning an impeller, of the centrifugal pump type, in the casing, and in the passageway, in such a manner. that its plane of rotation is inclined to the direction of a line joining the centers of the inlet and the discharge openings and inwhich the fluid enters the eye of the impeller and leaves the impeller chamber at the peripheral edge thereof I nearest the discharge opening, all as will be hereinafter described and shown on the drawings, an

- increased efllciency is obtained. so Having-thus, in a general way, described the with'the axis of rotation of the impeller.

Y A-A Fig. 1;

Figure 3 is a section taken on line CC Fig. 1; 10 Figure 4 is a section taken on line 3-3 Fig. 2; Figure 5 is a section taken on line D-D Fig. 1; Figure 6 is a side elevation of a propeller unit, showing the same mounted for rotation in an opening in the ship's bottom; 15

Figure 7 is a bottom plan view of the propelling .unit shown in Fig. 6;

Figure 8 is a fragmentary vertical section through the discharge end of the casing, showing adjustable means for varying the cross-sectional areas of the outlet; and

Figure 9 is a section, on a vertical plane, through a propeller unit designed for use on airships.

In the drawings reference numeral ll designates a portion of the frame comprising the bottom ll of a ship. The ships bottom has a rectangular opening for the propeller that has been designated in its entirety by number II. The propeller assembly comprises a frame of rectangular shape, having an outer frame member I3 provided along its upper edge with an outwardly extending flange ll that overlaps the upper flat surface lSof the frame II. The propeller assembly is secured in place by suitable bolts or 35 other means that have not been shown.

Supported by the frame of the assembly is a thrust casing whose bottom has been designated by number I 6 and whose sides have been designated by number I'I. Extending longitudinally through the casing is a eway comprising three sections A, B and C, designating respectively the inlet, the impeller chamber and the discharge opening. The passageway, section A, is enclosed by side walls It and a top I! and has 4 a vertical partition 20 that divides it into two parts and terminates in a'circular opening 2| that is concentric with the impeller and through which water or other fluid flows into the eye of the impeller. The impeller chamber B is formed by an enlargement of the passageway and its plane is upwardly and forwardly inclined with respect to a line joining the centers of the intake and the outlet openings. In the drawings the inlet section A of the eway has been 55 shown as upwardly and rearwardly curved and its axis, at the opening II, is practicalk pang impeller housing has a removable section 2!,

provided withflangecll tbatfltagainltflamec so 24. The removable section has an axial opening 25 through which the impeller shaft 28 extends,

astuflingboxflservestopreventleakageat this point. Section 22 has spaced integral portions 28 that connect it with an annular end member 2! to which the electric motor II is attached. Themotorisalsoattachedtoabace 3i. Secured to the forward end of shaft 2' is an impeller 32 having curved vanes 33. Hg. 3.

The impeller chamber has a special conduit flanditsbottomcommunicateswiththedischarge section of the The impellerisusuallyrotatedinthedirectionofthe arrowinl'lg.3andproducesaflowotfluidtmm the inlet to the outlet. It will be observed that the discharge from the impeller chamber takes place at its lowest point and in a direction approximately parallel with the plane of impeller rotation, the discharge section 0 of the passageway slopes downwardly and in a gen tle curve as shown in Fig. 1.

In order to prevent turbulence, to change the direction of the fluid and to receive thrust forces, the discharge pmage has been provided with a plurality of thrust vanes It whose inner, or forward ends are curved in the opposite direction to that in which the impeller rotates. The resultants of the forces acting on the fluid at this point are resisted by the curved ends of vanes Ii.

From Fig. 4 it will be seen that the vertical depth of the discharge section C decreases in the direction of impeller rotation. This is for the purpose of inducing a greater proportion of fluid to flowout while making the least change in its direction of flow.

The velocity of the buid flowing through the propeller is usually very high and on this account the passageway is not made unnecessarily long; as the loss of efliciency from this source is directly proportional to its length.

However, this loss is more than compensated for in some instances; as when engines having horizontal power shafts are employed and the impeller and chamber must be accommodated to this pomtion, the way then is extended and circinnvoluted accordingly; but its cross sectional areas are pmsressively changed to produce the required continuous acceleration of the fluid; otherwise. losses of energy are incurred which reduce the efliclency of the propeller still further.

In the embodiment of the invention illustrated inFigs. lto5,thecasingisnotrotatablebutis fixed and it can therefore not be used to steer the ship but only to propel it. Let us assume that the propeller described above is attached to an ocean going ship The e through the casing is always full of water since the casing is immersed.

When the impeller is rotated in the direction indicated by the arrow in Fig. 3, water is forced to flow from the intake to the outlet and, since the, cross sectional area of the eway decreases towards the'discharge end to an area substantially one-hall of that of the intake opening, the water will be increased in velocity twofold. This increase is accomplished by a gradual decrease in the cross sectional area of the passageway and results in a continuous positive increase in acceleration. 'Ihe force required toacceleratethewatervariesdirectlyastheacceleration and the energy with the mass and the square of the velocity. It is evident that the velocity at which the water is discharged has a great meet on the more 1cm but serious practical considerations make it more economical to move a greater mass than to employ very high velocities.

Although these propellers operate at their maximum efllciency, which corresponds to a theoretical condition representing 100% efllciency, whenthewateroriluid is at velocities or twice that of the ship. yet it is sometimesdesirabletochangetheratiobetweenthe areas oftheintakeandthewtletopenings and hillgjasimplemeansforthislllrmehasbeen shown. In the modifled construction shown in Fig.8,theupperwalloi'thedischargesection0 of the 1 is provided with reaction 38 thatcanberockedaboutthepivotfl. Abolt 38 isattached totheuppersurface ofthe movable section by a pivot II and extends through astufllngboxllintotheship. hunt is moimted for rotation in a bracket 42 and is held from longitudinal movement by circular flanges. When the nut is rotated bolt 38 moves upordowninaccordancewiththedirection of rotation and this varies the cross sectional area of the outlet.

It is sometimes desirable to be able to use the propeller for steering the ship and when this is desired the propeller frame is made round instead of square and is mounted for rotation in a round opening in the ship's bottom. In Fig. 6 the frame "a is circular and is provided with an annular flange I! that is positioned in a groove in the frame Ila. The propeller frame is provided around its upper edge with a worm gear thatisengagedbyaworm lisecuredbetween suitable bearings attached to the ship. When the worm is rotated the propeller frame is turned about a vertical axis. Means for rotating the worm has not been shown but any suitable mechanism such as is used for rudder control can be used. It is evident that when the propeller is rotatable, a rudder becomesunnecessary.

In Fig. 9 I have shown how a propeller of the typeabovedescribedcanbeappliedtoanairship and substituted for the ordinary propeller.

Numeral l6 designates the nacelle in which is positioned the motor 41. Shaft 28a carries an impeller 32. The inlet section of the fluid passage which corresponds to section A in Fig. l, hasbeendasAoandisshortand straight with forwardly flared wall. The outlet Ca communicates with the impeller chamber Be at the lowest point thereof and curves rearwardly sothattheairwillbedischarged rearwardly along the nacelle suri'ace.'

In addition to having a propeller at the nose, others may be provided at various places as indicated by numeral "a.

It will be seen from the above description that the propeller forming the subject matter is dei ned for efllclency and simplicity, that it does not impose its propulsive thrust on the impeller shaft and that its installation is more easily eilected than the ordinary screw propeller and the maximum efllciency attainable is greater.

with the shape of blades used in the type of impeller shown in Fig. 3. the direction 01 flow oi the fluid can be reversed by reversing the direc= Having described the invention what is claimed as new is:

1. A ship propulsion mechanism comprising in combination, an elongated casing having a passageway extending longitudinally therethrough and adapted to be secured to a ship, one end of the passageway being the inlet and the other end the outlet, a line joining the centers of the inlet and the outlet being substantially parallel with the direction of ships travel, the cross sectional area of the passageway decreasing progressively from the inlet to the outlet opening, in a manner to produce continuous acceleration of a fluid flowing therethrough, a portion of the passageway forming an impeller chamber, an impeller of the radial discharge centrifugal type, mounted for rotation in the chamber, the axis of rotation of the impeller being upwardly and forwardly inclined with respect to the direction of travel, and means for changing the cross sectional area of the outlet whereby the velocity of discharge can be varied.

2. A ship propeller mechanism, comprising in combination, an elongated casing having a passageway extending therethrough in the direction of ship travel, the front end serving as the intake for water and the rear end as the outlet, the wall of the passageway having an enlarged zone serving as an impeller chamber, positioned at an intermediate point, the plane of the zone being upwardly inclined in the direction of the intake, an impeller mounted to rotate in the enlarged zone about a power shaft upwardly inclined in the direction of the outlet, the casing having a portion of the impeller chamber wall removable, the removable portion having an opening for the power shaft, the intake and the discharge openings being aligned with the direction of ships travel, the under wall surface of the intake and discharge openings connecting respectively with the eye and the lowermost portion of the impeller chamber by curved portions.

3. An elongated propeller thrust casing adapted to be attached to a ship, the casing being exteriorly streamlined to reduce resistance tb movement through water to a minimum, the casing having a passageway extending from one end to the other in the direction of ships travel, the endsof the passageway being substantially parallel, means comprising a fluid impeller positioned in the passageway for acting upon water contained therein to increase its velocity, said impeller being rotatable in a plane upwardly inclined in the direction of the intake, the outlet being below the lower edge of the impeller, means comprising walls having curved surfaces, for changing the direction of the fluid stream as it leaves the impeller, means comprising the walls of the intake opening to direct the fluid to the eye of the impeller, the passageway decreasing in cross section from the intake to the discharge whereby the fluid passing through the same will be increased in velocity from intake to outlet, and means comprising a pivoted wall section for changing the cross sectional area of the outlet p ning.

4. A hydraulic propeller unit for attachment to a ship's hullhaving an opening in its bottom comprising a frame having an outwardly extending flange for supporting the frame in the opening, a thrust casing attached to the frame, the casing having a passageway, the intake and the discharge openings of the passageway being located below the level of the under surface of the frame, a portion of the passageway being enlarged to form an impeller chamber, both ends of the passageway curving upwardly towards the impeller chamber, a single eye impeller in the chamber, mounted for rotation about an axis substantially parallel with the axis of the communicating end of the intake passage, the upper end of the discharge passage being substantially parallel with the plane of rotation of the impeller.

5. A ship propulsion mechanism comprising, in combination, a casing having a passageway extending therethrough and adapted to be attached to a ship, one end of the passageway being the inlet and the other end the outlet, a line joining the centers of the inlet and the outlet being substantially parallel with the direction of ship travel, the cross sectional areas of the passageway decreasing progressively from the inlet to the outlet opening in a manner to produce continuous acceleration of a fluid flowing therethrough, a portion of the passageway forming an impeller chamber, an impeller of the radial discharge centrifugal type operatively mounted in the chamber, and means for changing the cross sectional area of the outlet whereby the velocity of discharge can be varied.

6; A ship propeller mechanism, comprising, in combination, a casing having a passageway extending therethrough in the direction of ship travel, the front end serving as the intake and the rear end as the outlet, the passageway having an enlarged zone serving. as an impeller chamber, positioned at an intermediate point, an impeller mounted to rotate in the enlarged zone, a power shaft passing through the casing wall and operatively connected with the impeller, the casing having a portion of the impeller chamber wall removable, the removable portion having an opening for the power shaft, the intake and outlet openings being aligned with the direction of ship travel, the intake and outlet openings connecting respectively with the eye and the peripheral portion of the impeller chamber by passageways having curved walls.

'7. In combination with a ship having an opening in the bottom of its hull, a propulsion apparatus positioned in the'opening, said apparatus comprising a thrustcasing having a passageway extending therethrough, one end forming an inlet and the other the outlet, the distance between the inlet and the outlet being less than the corresponding dimensions of the opening whereby the casing may be inserted from the inside of the ship, an intermediate portion of the passageway being enlarged to form an impeller chamber, a line joining the inlet and outlet openings being substantially parallel with the direction of ship travel, a continuous wall attached to the casing above the inlet and outlet opening, the wall being of a size and shape to fit the opening in the hull, the upper edge of the wall having an outwardly extending element for projecting over the wall of the opening in the ships. hull to support the casing, the inlet and outlet openings being positioned wholly below the hull, the passageways connecting the inlet and outlet openings curving upwardly to an impeller chamber which is positioned within the hull, the portion of the casing below the hull being streamlined.

ALBERT F. ANDERSON.