Narrow-outlet splitter for a personal propulsion system

A novel two-way splitter having reduced distance between outlets, while enabling smooth, efficient fluid flow (e.g., water flow) is provided. In a variant, the splitter includes a first pipe and a second pipe meeting at an interface near the inlet and extending away from the inlet, wherein portions of the first pipe and the second pipe proximal to the inlet are substantially helical and are intertwined with each other. In another variant, the first and second pipes have first portions proximal to the inlet which extend vertically side by side away from the inlet, such that the width of each first portion decreases and the depth of each first portion increases as a vertical distance from the inlet increases.

TECHNICAL FIELD

The present invention, in some embodiments thereof, relates to devices and systems based on water jet for propelling a user to fly above a surface.

BACKGROUND OF THE INVENTION

Flight has always been a dream of mankind. In modern history, this dream has been achieved, and various flying vehicles have been produced to enable people to fly. Generally, these vehicles, such as airplanes or helicopters, enclose the user (pilot or passenger) and allow little freedom to the passenger's control of the flight.

Some personal propulsion systems have been designed to carry a single person while providing the user increased control of the user's flight via motion of the user's body.

U.S. Pat. No. 8,336,805 describes a propulsion device comprising a body arranged for receiving a passenger and engaging with a thrust unit supplied with a pressurized fluid from a compression station. The arrangement of such a device offers great freedom of movement through the air or under the surface of a fluid. U.S. Pat. No. 8,336,805 also discloses a propulsion system in which the compression station can be remote in the form of a motorized marine vehicle.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

The aim of the present invention is to increase the user's freedom of movement while using a personal propulsion system. Another aim of the present invention is to improve stability a personal propulsion system.

FIG. 1illustrates a personal propulsion system100as known in the prior art. A pump102pumps a fluid122(e.g., water) from a fluid reservoir (e.g., sea, lake, pool), and sends a fluid flow124through a flexible tube106. The tube is connected to a splitter109, which is attached to two nozzles110and111. The splitter109splits the flow124into two flows that enter the nozzles and are ejected as flows126and128. The nozzles110and111are located below a platform113which supports the user, and face away from the user. In this manner the nozzles110and111eject fluid flows126and128away from the user, and propel the user in a direction opposite to that of from the ejected fluid's flow. The user can change the orientation of the nozzles by changing the orientation of his or her body. In some embodiments, the platform113is replaced by two separate platforms or foot mounts, each associated with a respective nozzle. Each platform or foot mount is joined to a respective foot of the user.

The inventor has found that reducing the spacing between the outlets of a two-way splitter improves the performance and handling of the personal propulsion system. Commonly, reducing the spacing between the outlets of the splitter entails increasing/sharpening the curvature of the pipes that make up the splitter. This, however, generally introduces turbulence in the flow of the fluid, and degrades the performance of the system.

Thus, an aim of the present invention is to provide a novel two-way splitter having reduced distance between outlets, while enabling smooth, efficient fluid flow (e.g., water flow).

Therefore, an aspect of some embodiments of the present invention relates to a flow splitter configured for splitting a first fluid flow into two second flows and for changing a direction of each second flow with respect to a direction of the first flow. The flow splitter comprises an inlet, configured for receiving the first flow, and a first pipe and a second pipe meeting at an interface near the inlet and extending away from the inlet, such that the interface divides a first cross-sectional area of the inlet into two second cross-sectional areas. Portions of the first pipe and the second pipe proximal to the inlet are substantially helical and are intertwined with each other. The first pipe and the second pipe have a first outlet and a second outlet respectively at ends of the respective pipes, the first and second outlet facing away from each other.

In a variant, central axes of the first and second pipe at the outlets form substantially right angles with a central axis of the splitter at the inlet.

Optionally, central axes of the first and second pipe at the outlets form an angle of about 180 degrees between each other.

In another variant, a cross-sectional surface of the inlet is circular or oval, such that cross sectional surfaces of the pipes at the inlets are D-shaped. The cross-sectional surface of each pipe smoothly morphs from the D-shape into an oval shape at the respective outlet.

In yet another variant, a cross-sectional surface of the inlet is circular or oval, such that cross sectional surfaces of the pipes at the inlets are D-shaped. The cross-sectional surface of each pipe smoothly morphs from the D-shape into an oval shape along the pipe. The cross-sectional surface of each pipe smoothly morphs from the oval shape along the pipe to a circular shape at the respective outlet.

In a further variant, the interface is a panel extending between two points of a circumference of the inlet.

Optionally, the interface has an aerodynamic shape, configured for maintaining low drag in the second flows.

Optionally, an edge of the interface proximal to the inlet has a frontal cross section perpendicular to the interface's larger surface having a parabola's shape, such that a vertex of the parabola is a point of the interface that is farthest from the outlets.

In yet a further variant, a cross sectional of each pipe is about constant along at least a portion of the respective pipe.

Another aspect of some embodiments of the present invention relates to a flow splitter configured for splitting a first fluid flow into two second flows and for changing a direction of each second flow with respect to a direction of the first flow. The flow splitter comprises: an inlet, configured for receiving the first flow. A first pipe and a second pipe meeting at an interface near the inlet and extending away from the inlet, such that the interface divides a first cross-sectional area of the inlet into two second cross-sectional areas. The first and second pipes have first portions proximal to the inlet which extend vertically side by side away from the inlet, and second portions distal from the inlet which curve from each other at respective angles and end at respective outlets. For each of the first portions, a width for any vertical point is the largest horizontal distance perpendicular to the interface between the interface and an inner surface of the pipe. For each of the first portions, a depth for any vertical point is the largest horizontal distance parallel to the interface between two points at an inner surface of the pipe. For each of the first portions, the width decreases and the depth increases as a vertical distance from the inlet increases.

In a variant, a cross-sectional area of the each pipe is substantially constant along the respective pipe.

In another variant, central axes of the first and second pipe at the outlets form substantially right angles with a central axis of the splitter at the inlet.

Optionally, central axes of the first and second pipe at the outlets form an angle of about 180 degrees with each other.

In another variant, the interface is a panel extending between two points of a circumference of the inlet.

Optionally, the interface has an aerodynamic shape, configured for maintaining low drag in the second flows.

Optionally, an edge of the interface proximal to the inlet has a frontal cross section perpendicular to the interface's larger surface having a parabola's shape, such that a vertex of the parabola is a point of the interface that is farthest from the outlets.

According to some embodiments of the present invention relates to an apparatus for a personal propulsion system. The apparatus comprising: a helical flow splitter described above having a diameter of about 4 inches at the inlet and a distance between outlets of about 6 inches, and two nozzles attached to the respective outlets of the flow splitter, the nozzles configured for receiving the fluid from the flow splitter and having respective exits for emitting respective jets at a angles substantially perpendicular to the central axes of the first and second tubes at the outlets. A distance between the exits of two nozzles is equal to or less than about 27 inches.

In a variant, the apparatus includes two foot mounts, each foot mount being configured for being secured to a respective foot of a user, and each foot mount being joined to a respective nozzle and/or to a respective bearing which joins the respective nozzle to the respective outlet, wherein each nozzle exit is vertically aligned with a respective foot mount.

In another variant, the apparatus includes two foot mounts, each foot mount being configured for being secured to a respective foot of a user, and each foot mount being joined to a respective nozzle and/or or to a respective bearing which joins the respective nozzle to the respective outlet. A distance between any nozzle exit and a central axis of the flow splitter at the intake is smaller than a distance between a center of any of the foot mounts and the central axis.

According to some embodiments of the present invention relates to an apparatus for a personal propulsion system. The apparatus includes: a flat flow splitter as described above having a diameter of about 4 inches at the inlet and a distance between outlet of about 6 inches, and two nozzles attached to the respective outlets of the flow splitter, the nozzles configured for receiving the fluid from the flow splitter and having respective exits for emitting respective jets at a angles substantially perpendicular to the central axes of the first and second tubes at the outlets. A distance between the two nozzles is equal to or less than about 27 inches.

In a variant, the apparatus includes two foot mounts, each foot mount being configured for being secured to a respective foot of a user, and each foot mount being joined to a respective nozzle and/or to a respective bearing which joins the respective nozzle to the respective outlet, wherein each nozzle exit is vertically aligned with a respective foot mount.

In another variant, the apparatus includes two foot mounts, each foot mount being configured for being secured to a respective foot of a user, and each foot mount being joined to a respective nozzle and/or to a respective bearing which joins the respective nozzle to the respective outlet, wherein a distance between any nozzle exit and a central axis of the flow splitter at the intake is smaller than a distance between a center of any foot mount and the central axis.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

From time-to-time, the present invention is described herein in terms of example environments. Description in terms of these environments is provided to allow the various features and embodiments of the invention to be portrayed in the context of an exemplary application. After reading this description, it will become apparent to one of ordinary skill in the art how the invention can be implemented in different and alternative environments.

Before describing embodiments of the present invention, it should be noted, that the terms “cross-sectional area” and “cross-sectional surface” of a pipe refer to the surface of a pipe that is perpendicular to the central axis of the pipe.

Referring now toFIGS. 2-4, drawings are provided illustrating a two-way helical splitter200, according to some embodiments of the present invention.FIG. 2is a top view of the splitter200.FIG. 3is a side view of the splitter200.FIG. 4is a perspective view of the splitter200.

The splitter is a tube which includes an inlet201and two outlets202and204. The flow is separated at the inlet by a panel206at the inlet. The panel206divides the cross-sectional surface of the inlet in two surfaces. Optionally, the inlet is circular or oval, and the panel divides the surface of the inlet into two D-shaped surfaces. The panel206is the interface at which two pipes212and214connect to form the intake201. The first flow passes through the first pipe212to reach the first outlet202. The second flow passes through the second pipe214to reach the second outlet204.

Portions of the pipes212and214that are near the inlet are substantially helical, and the outlets202and204face away from each other at opposite directions. The helical portions of the pipes are intertwined with each other. In some embodiments of the present invention, central axes of the outlets form angles of about 90 degrees with the central axis of the inlet. In this manner, the flows are bent by about 90 degrees from the inlet to the respective outlets. Optionally, central axes of the pipes form an angle of about 180 degrees. The helical shape of the pipes212and214bends each fluid flow to soften the bend angle over a smooth, wide radius curve. The helical path enables maintaining a low curvature along the pipes212and214, while reducing the spacing between outlets. Therefore, on the one hand, lower curvature improves the flow efficiency, decreases turbulence, and thus decreases the energy spent by the pump to pump the fluid from the fluid reservoir to the outlets. On the other hand, the reduced distance between outlets improves performance and handling of the personal propulsion system.

The panel206optionally has an aerodynamic shape, to reduce drag in the flow and to maintain a smooth flow through the splitter200. In a non-limiting example, the lower edge of the panel206is shaped like a parabola where the vertex of the parabola is the lowest point of the panel (i.e., a point of the interface that is farthest from the outlets).

In some embodiments of the present invention, the outlets have oval shape. In a variant, each pipe smoothly morphs the D-shape at the entry into oval-like shape at the respective outlet. According to some embodiments of the present invention, the outlets have circular shapes. To achieve this shape, each pipe smoothly morphs the D-shape at the entry into an oval-like shape along the pipe, and then morphs the oval-like shape into a circular shape at the respective outlet.

In some embodiments of the present invention the cross sectional area in the pipes is maintained substantially constant in at least a portion of each pipe. This feature decreases turbulence and increases the efficiency of the fluid flows.

It should be noted that in some embodiments of the present invention, the inlet's cross-sectional area is split into two substantially equal portions by the panel. In a variant, the inlet's cross-sectional area is split by the panel into two unequal portions.

Reference is now made toFIGS. 5-7, which are drawings illustrating a flat splitter300, according to some embodiments of the present invention.FIG. 5is a perspective view of the splitter300.FIG. 6is a front view of the splitter300.FIG. 7is a side view of the splitter300.

The flat splitter300is a tube which has an inlet301and two outlets302and304. The flow entering the flat splitter is split at or just after the inlet, by a panel/interface306which divides the cross-sectional surface of the inlet into two parts. Optionally, the inlet is circular or oval, and the panel divides the surface of the inlet into two D-shaped surfaces. The panel306extends parallel to normal axis of the cross-sectional surface of the intake, and divides the tube into two pipes312and314having outlets302and304, respectively. The pipes312and314extend side by side vertically away from the inlet and then curve away from each other and from the panel to release the respective fluid flows from the respective outlets302and304facing away from each other. Optionally the outlets' normal axes are at about 180 degrees from each other.

As it can be clearly seen inFIGS. 6 and 7, along the straight portions of each pipe, the width of the each pipe decreases while the depth of each pipe increases as the distance from the inlet grows. The width at any vertical point may be defined as the largest horizontal distance perpendicular to the interface/panel between the interface/panel and the inner surface of the pipe. A depth for any vertical point is the largest horizontal distance parallel to the interface/panel between two points at an inner surface of the pipe. For example, the width w1 near the base of the pipe314is larger than the width w2 located farther than the base of the pipe314. The depth d1 (at the same point as the width w1) is larger than the depth d2 (at the same point as the width w1).

Because the width of the pipes narrows, the curvature of each pipe is gentler (i.e. having a larger radius of curvature) than the curvature of a pipe known in the art. As shown inFIG. 6, the shape of a pipe which is part of a two-way splitter known in the art having a decreased distance between outlets has a first straight portion a, a second curved portion b, and a third straight portion c. The curved portion b has a tight curvature (i.e., as a small radius of curvature), which compromises the flow efficiency of the fluid through the pipe. In contrast, the shapes of the pipes312and314describe gentler curves from the inlet to the respective outlets302and314, without compromising flow efficiency, and enabling a narrow distance between the outlets.

As the width of each pipe decreases, the depth of each pipe increases, as can be seen onFIG. 7. The increase in depth ensures that the cross-sectional area of each pipe is maintained substantially constant along the pipe's length. As mentioned above, this feature helps reduce turbulence in the flow through the pipes.

Optionally, the panel306has an aerodynamic shape, to reduce drag in the flow and to maintain a smooth flow through the splitter300. In a non-limiting example, the lower edge of the panel306is shaped like a parabola the vertex of which is the lowest part of the parabola.

In some embodiments of the present invention, the outlets have an oval shape. In a variant, each pipe smoothly morphs the flat shape near along the substantially straight section of the pipe to an oval-like shape at the respective outlet. According to some embodiments of the present invention, the outlets have circular shapes. To achieve this shape, each pipe smoothly morphs the flat shape near along the substantially straight section of the pipe to an oval-like shape before the outlets, and then morphs the oval-like shape into a circular shape at the respective outlet.

The shapes of the splitters200and300enable a decreased distance between the outlets, and therefore a decreased distance between the nozzles joined to the outlets. By using the splitters200and300, the inventors have constructed a splitter having a diameter of about 4 inches at the inlet and a distance between outlets of about 6 inches. Using dual row 10 mm ball bearings to connect each outlet to a respective nozzle, the distance between the exits of the nozzles is below 27 inches.

Referring now toFIGS. 8-10, schematic drawings are provided illustrating user-side apparatuses of a personal propulsion system, each having a respective different configuration of the foot mounts joined to the user's feet in.FIG. 8illustrates an example in which the distance between the foot mounts is larger than the distance between the exits of the nozzles.FIG. 9illustrates an example in which the distance between the foot mounts is about equal to the distance between the exits of the nozzles.FIG. 10illustrates an example in which the distance between the foot mounts is smaller than the distance between the exits of the nozzles.

Thanks to the decreased distance between the outlets splitters200and300, the inventors have constructed and tested a personal propulsion apparatus in which the foot positions on the platform113ofFIG. 1are located right above the exits of the nozzles, without increasing the distance between the user's feet. In another embodiment, instead of using a single platform113, the inventors have used foot mounts114and115. The foot mounts114and115are joined to respective nozzles110and111and/or to respective bearings400and402(which may or may not be present), each bearing joining the respective nozzle to the respective outlet of the splitter. Each foot mount is located above a respective nozzle, such that the foot position on each foot mount is right above the exit of the respective nozzle. Using a splitter of the present invention having an inlet diameter of about 4 inches and an outlet distance of about 6 inches, as well as dual row 10 mm ball bearings attached to respective outlets, the inventors have designed a user side apparatus of a personal propulsion system in which the jets emitted by the nozzles are under the user's feet, and the user has a comfortable stance in which the distance between the user's feet and the distance between the jets are around 21.6 inches. In contrast, in the prior art, because of the large distance between the outlets of the splitter, aligning the foot with the exits of the nozzles, would require the user to spread the user's legs and maintain an uncomfortable stance while using the personal propulsion system. It should be noted that the distance between jets can further be decreased by either connecting the nozzles to the splitter without bearings, or by improving bearing design to decrease the size of the bearings.

Aligning the nozzles' exits (and therefore the source of thrust) with the user's feet causes a more predictable response to the user's control inputs. The user feels more “connected” to the personal propulsion system, and this makes the user feel more in control and stable.

As mentioned above, in some embodiments of the present invention, each nozzle is joined to the respective outlet of the splitter via a respective bearing. This bearing is configured for enabling a rotation of the nozzle with respect to the splitter. In this manner, the user is able to use his/her body stance to control the direction of the jets (i.e., the direction of thrust). Since the feet of the user are right above the exits of the nozzles, the weight of the rider is placed directly above the line of thrust. In this manner the load on the bearings is decreased, and the friction of the bearings' movement during use is decreased, thereby prolonging the lifetime if the bearings.

In some embodiments of the present invention, the decreased distance between the outlets of the splitter, enables the distance between exists of the nozzles to be smaller than the distance between the user's feet. For example, a splitter having an inlet having a diameter of about 4 inches and a distance between outlets between 4 and 6 inches, can be connected to two nozzles via respective dual row 10 mm ball bearings, in which the distance between the exits of the nozzles is below 20 inches. A jet span narrower than the user's stance can increase responsiveness and maneuverability of the personal propulsion system.