US3285214A

US3285214A - Mechanism for use in conjunction with the intake opening of a water jet propelled hydrofoil vehicle

Info

Publication number: US3285214A
Application number: US486344A
Authority: US
Inventors: Jr Roy A Patton
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-09-10
Filing date: 1965-09-10
Publication date: 1966-11-15
Anticipated expiration: 1983-11-15

Description

Nov. 15, 1966 R. A. PATTON, JR 3,235,214 MECHANISM FOR USE IN CONJUNCTION WITH THE INTAKE OPENING OF A WATER JET PROPELLED HYDROFOIL VEHICLE Filed Sept. 10, 1965 5 SheetsSheet l INVENTOR ROY A. PATTON Jrv BYM MN M ATTORNEYS Nov. 15, 1966 R. A. PATTON, JR 3,285,214

MECHANISM FOR USE IN CONJUNCTION WITH THE INTAKE OPENING OF A WATER JET PROPELLED HYDROFOIL VEHICLE Filed Sept. 10, 1965 5 Sheets-Sheet 2 INVENTOR ROY A. PATTON, Jr.

ATTORNEYS Nov. 15, 1966 PATTON, JR 3,285,214 MECHANISM FOR USE IN CONJUNCTION WITH THE INTAKE OPENING OF A WATER JET PROPELLED HYDROFOIL VEHICLE Filed Sept. 10, 1965 5 Sheets-Sheet 5 EIE El INVENTOR ROY A. PATTON Jr.

BY Z/ J 911 l ATTORNEYS United States Patent 3,285,214 MECHANESM FOR USE IN CONJUNCTION WITH THE INTAKE OPENING OF A WATER JET PRO- PELLED HYDROFGIL VEHICLE Roy A. Patton, .Jr., 6030 N. Shore Drive, Grabill, Ind. Filed Sept. 16, 1965, Ser. No. 486,344 7 Claims. (Cl. 11466.5)

The present invention relates generally to a mechanism for use in conjunction with the intake opening of a water jet propelled hydrofoil vehicle, and more particularly to a mechanism for improving the operation of the intake port in such a vehicle.

One type of jet propelled hydrofoil vehicle is a boat provided with an engine driven pump which draws water through intake openings respectively located in hydrofoil members which are secured to the bottom of the boat. The pump imparts a high velocity to the water and discharges the water from the rear of the boat. This high velocity discharge of water from the rear of the boat provides the boats locomotion.

During normal operation of the boat, the relative velocity between the water and the hull of the boat varies; and thus, the water entering the intake port enters at varying velocities. The range of the velocities of water entering the intake port of such a boat generally is suflicient to require the intake port to be adjustable in size. Efficient jet boat operation depends upon the availability and delivery of water at the pumps capacity at all times and under all phases of boat operation. Many jet boats heretofore have been designed with an intake opening of a size that ensures efficient operation only under a small range of operating conditions. When the boat is standing still, just prior to acceleration, or is moving slowly, the opening is sufficient if it is large enough to permit the pumps fluid capacity to flow theret'hrough. As the boat picks up speed, the relative velocity of the water aids in the delivery of water to the pump as long as the flow remains generally laminar. As soon as turbulence develops, however, the fluid will vortex, froth, or in other ways develop air pockets in the water entering the intake opening, thereby presenting to the pump a mixture of air and water rather than water alone. Such a mixture in flowing through the pump may have deleterious effects on the pump and will cause a loss of thrust. It has long been suspected that the deleterious effects on the pump may include the actual fracturing of the turbine-like blades of the pump. It is therefore desirable under some conditions to have a somewhat larger intake opening than that theoretically efficient for slow speeds so that an increased volume of mixture may be presented to the pump, thereby regaining a part of the water volume lost. At relatively high speeds, the relative velocity of the fluid impinging on the intake opening aids in the compression of the air-water mixture by the pump resulting in a gain in elficiency. Opposing this gain in efficiency is a drag and a loss of power caused by the compression of the air-water mixture and what is commonly called ram jet action. It is therefore desirable to compress only that amount of mixture that will result in the proper amount of water being fed to the pump, thereby to hold the drag and the ram jet action to a minimum. This calls for a reduction in the size of the intake opening, possibly beyond the size used for slow speeds. Any change in the size of the intake opening is, of course, preferably made without making any change in the shape of the opening which would tend to encourage turbulent flow.

It is therefore the primary object of this invention to provide an improved mechanism for use in conjunction 3,285,214 Patented Nov. 15, 1966 with the intake opening of a water jet propelled hydrofoil vehicle for varying the size of the intake opening.

It is another object of this invention to provide an improved mechanism for selectively varying the size of an intake opening which is substantially circular without substantially varying the shape of the opening.

It is still another object of this invention to provide an improved mechanism for varying the size of an intake opening which does not alter the smoothly shaped oonfiguration of the intake opening.

It is still further an object of this invention to provide a mechanism for varying the size of an intake opening which is hydraulically or pneumatically actuated.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of one embodiment of a water jet propelled hydrofoil vehicle which utilizes the device of this invention;

FIG. 2 is a cross-sectional view of the vehicle illustrated in FIG. 1 taken substantially along the section line 22;

FIG. 3 is a fragmentary, broken-away and enlarged view of one of the four hydrofoil members which are secured to the hull of the vehicle illustrated in FIG. 1; and

FIG. 4 is a fragmentary front view of the hydrofoil member illustrated in FIG. 3.

In the broader aspects of this invention there is provided a hull, an engine mounted in the hull, a pump mounted in the hull and being operatively connected to the engine, and one or more hydrofoil members having inlet ports therein. The hydrofoil members are hollow and connected to the inlet duct of the pump and have means therein for controlling the size of the intake inlet port. The hull further 'has means including the exhaust duct of the pump mounted therein for propelling the hull in response to operation of the engine and the pump.

Referring now to the drawings, a liquid, jet propelled hydrofoil boat 10 is shOWn having a hull 12, a conventional marine engine 14 mounted in the hull and operatively connected by a shaft 16 to a pump 18 which has a discharge opening 20 at the rear of the boat. Secured to the hull 12 are four hydrofoil members 22. Hydrofoil members 22 depend below the bottom 24 of the hull 12 and generally comprise an enlarged portion 28 and a neck portion 26 extending between the portion 28 and the hull 12.

Referring now specifically to FIGS. 3 and 4, there is shown one of the hydrofoil members 22. Since all of the hydrofoil members 22 are substantially identical, the description of one will SUifiCG for the description of the remaining members. Enlarged portion 28 has a substantially rigid shell 30 which is generally circular in cross-section and has a longitudinal axis 32. Shell 30 has an interior surface 36 and an open end or intake port 34 defined by a smoothly rounded lip 35. Shell 30 further is streamlined in the general direction of the axis 32 away from the open end 34 and is connected to the neck portion 26 by means of a collar 38. Neck portion 26 extends through the shell 30* and terminates within the enlarged portion 28 at the distal end 40 thereof. Extending between the lip 35 and the distal end 40 is flexible, self-supporting and resilient interior liner 42 which has

opposite ends

44 and 46. Liner 42 is secured adjacent to

ends

44 and 46, respectively, to the lip 35 and the neck portion 26 thereby forming a continuous and smoothly shaped passage between the open end 34 of the enlarged portion 28 and the neck portion 26. Liner 42 defines a throat portion 48 intermediate the open end 34 of the enlarged portion 28 and the neck portion 26. Liner 42 further defines an annular space 50 intermediate the shell 30 and the liner 42. Positioned within the annular space 50 is a resiliently expandable and generally toroidal or doughnut-shaped member 52. While member 52 is generally circular in cross-section when not in position, member 52 is flattened between the interior surface 36 of the shell 30 and the liner 42 when positioned in space 50. Connected to the member 52 is an inlet tube 54 and an exhaust tube 56. Inlet tube 54 and exhaust tube 56 are encased in a tubular cover 59 within neck portion 26 and extend the full length of the neck portion 26 and into the hull 12, as will be hereinafter described.

In a specific embodiment of this invention, the boat 10, the hull 12, the engine 14, and the pump 18 can all be made of materials from which conventional boat hulls, engines and pumps are made. The exterior shell 30' of the portion 28 and the neck portion 26 of the hydrofoil members 22 can be made of any substantially rigid and strong material, such as metal, reinforced polyester materials, or similar materials. The interior liner 42 preferably is m ade of resilient, flexible and self-supporting polyester sheet material. The toroidal member 52 and the inlet and

exhaust tubes

54 and 56, respectively, are preferably made of rubber, synthetic rubber or rubber-like materials. Neoprene has proven to be satisfactory.

In the specific embodiment illustrated, the interior liner 42 is formed adjacent to its

opposite ends

44 and 46 to join with the lip 35 adjacent to the opening 34 and the end 40 of the neck portion 26 in an overlapping fashion. Lip 35 and neck portion 26 are secured to the liner by adhesives or the like and a retaining ring 58 adjacent each of the

ends

44 and 46 to hold each of the joints in overlapping relationship.

Each of the neck portions 26 of the respective hydrofoil members 22 are secured to the hull 12 as aforementioned and illustrated in FIG. 1. Referring now to FIG. 2, there is shown both the manner in which the respective neck portions 26 of each of the hydrofoil members 22 are connected to the inlet duct 60 of the pump 18 and the mechanism by which the toroidal members 52 can be selectively expanded and contracted. First, referring to the connection of the respective hydrofoil members 22 to the pump 18, there is shown a hollow manifold 62 having four

legs

64, 66, 68 and 70, respectively. Each of the legs 64 through 70, respectively, is connected with the neck portion 26 of one of the hydrofoil members 22. Further, each of the leg members 64 through 70 extend from the respective hydrofoil members 22 into the main body portion 72 of the manifold 62. Body portion 72 has at one end a flange 74 which is secured to a flange 76 of the inlet duct 60 of the pump 18. Thus, by means of the manifold 62 and the respective hydrofoil members 22, water flowing into each of the intake ports 34 located in the enlarged portions 28 of the hydrofoil members 22 flows into the throat portion 48- and into the interior of the neck portions 26, and thence, into the manifold mem-' ber 62 and into the pump 18.

As aforementioned, the inlet and

exhaust tubes

54, 56 leading to each of the toroidal members 52 within the respective hydrofoil members 22 extend upwardly through the full length of the neck portions 26 and into the hull 12.

Tubes

54 and 56 from each of the toroidal members 52 in each of the respective hydrofoil members 22 further extend into the respective legs 64 through 70 of the manifold 62 and into the

conduits

78, 80, 82 and 84, respectively, connecting with the manifold 62. Conduits 78 through 84 and the

respective tubes

54 and 56 contained therein connect into a second manifold device 86 which is connected to a conventional pump and motor combination 88. Each of the

tubes

54 and 56 has a oneway check valve therein (not shown). The pump of the combination 88 is in turn connected to a fluid reservoir 90 by means of connecting

tubes

92 and 94. In this manner, the interior of each of the toroidal members 52 is connected by means of the

tubes

54 and 56, the manifold member 86, the pump of the combination 88, and the connecting

tubes

92 and 94 to the fluid reservoir 90.

In a specific embodiment, the reservoir 90, the conduits 78 through 84, and the

tubes

92 and 94 can be made of any suitably strong and durable material. Metal, plastic and like materials have proven satisfactory for the conduits 78 through 84, the

tubes

92 and 94, and the reservoir 90. The motor and pump combination 88 can be conventional in all respects.

In operation, the boat 10 operates similarly in most respects to other water jet propelled hydrofoil vehicles. In response to the operation of engine 14, pump 18 is operated thereby providing a suction at the inlet 60 thereof. Water enters each of the intake ports 34 in response to the suction of the pump 18 and is sucked through the respective throat portions 48 and int-o the respective neck portions 26. The water is then sucked upwardly through the neck portions 26 and into the manifold 62 and into the pump 18. Between the intake ports 34 and the pump 18, the continuous conduit defined by the lip 35, liner 42, neck portion 26 and manifold 62 is smoothly shaped. When the boat is standing still or is moving slowly, the water flows smoothly through this continuous conduit without turbulence. Pump 18 imparts a high velocity to the water and exhausts the water through the exhaust duct 20 in a high velocity stream 100, as shown in FIG. 1. Stream acts to propel the 'boat much in the same way as an airplane is propelled by a conventional jet engine. As the 'boat 10 picks up speed, the relative velocity between the boat 10 and the water increases thereby providing that the water entering the intake ports 34 of the respective hydrofoil members 22 enters with an increased velocity. This increased water velocity results in the flow of the water between the opening 34 and the pump 18 to be at a higher velocity than when the boat 10 was stationary. As the boat 10* increases in speed, the velocity of the water between the intake ports 34 and the pump 18 will likewise increase. As aforementioned, as the velocity of the water flowing to the pump 18 increases, a certain water velocity will be reached when turbulent flow will predominate within the hydrofoil members 22 if the size of the intake port 34 is not made smaller. Since such flow is undesirable, the apparatus of this invention provides for adjusting the size of the intake ports 34 in the region of the throats 48 in order that the development of turbulent flow within the hydrofoil members 22 may be retarded and laminar flow may be emphasized.

For example, each of the intake ports of the respective hydrofoil members 22 can be reduced in size by operating the motor-pump combination 88 to transfer fluid from the reservoir 90 through the

pipes

92 and 94 and the inlet tubes 54 into the respective toroidal members 52. The check valves aforementioned (not shown) Within tubes 56 prevent fluid from flowing into tubes 56.

This fluid being pumped into the toroidal members 52 expands the toroidal members radially inwardly against the liner 42 thereby causing a necking down and reduction in size of the throat portion 48 of the liner 42 as indicated by the dashed lines 102. Since the expansion of the toroidal members 52 is a result of pressure being exerted by the fluid within each of the toroidal members 52, in all directions, the liner 42 is moved away from shell 30 an equal distance measured along each radial line of direction. This movement of the liner 42 results in a reduction of the cross-sectional size of the throat portion 48 thereof without a corresponding change in cross-sectional shape. By this means, a smaller cross-sectional area of the inlet ports 34 is achieved while the initial shape of the ports, illustrated in FIG. 4 to be circular in cross-section, and the smoothly shaped configuration of the conduits defined by the lips 35, liner 42, neck portions 26 and manifold 62 are substantially retained. This reduction in size of the inlet ports 34 results in the restriction of flow of water into the respective neck portions 26 and the manifold 62 thereby lowering the velocity of the water therein and maintaining the flow to the pump 18 in a predominantly laminar form.

Similarly, whenever the intake ports of the respective hydrofoil members 22 are desirably increased in size, for example when the velocity of the boat 10 decreases, the motor-pump combination 88 is operated to transfer fluid from the toroidal members 52 back into the reservoir 90 by way of the respective exhaust tubes 56 and the

pipes

92 and 94. Fluid flow in the inlet tubes 54 is prevented by the check valves therein (not shown) aforementioned. When sufiicient fluid has been withdrawn from the toroidal members 52, toroidal members 52 resiliently contract in size and the respective liners 42 resiliently will move radially outwardly toward the shells 30 thereby enlarging the cross-sectional size of the throat portions 48. When enough fluid has been withdrawn from the toroidal members 52, the liners 42 will assume the position shown in FIGS. 3 and 4 in solid lines which corresponds to the maximum port size.

Thus, in all stages of operation, the volume of water required by the pump desirably smoothly flows through the neck portions 26 and the manifold 62 to the pump 18 in predominantly laminar flow. The throat portion 48 which can be adjusted in size as aforementioned operates to restrict the flow of water therethrough thereby to allow only that volume of water required by the pump 18 into the respective neck portions 26. In this manner, laminar flow is assured within the neck portions 26 and the manfold 62.

Turbulence can and does occur within the enlarged portions 28 between the intake opening 34 and the throat portion 48 at the higher boat velocities. This turbulence, in the extreme case, is caused by both the relatively high velocity of the water entering the enlarged portions 28 through the intake ports 34 and by the fact that more water enters the enlarged portions 28 than is allowed to pass through the throat portions 48, thereby requiring some of the water within the portions 28 to flow out of the intake ports 34 against the incoming flow of water. This reverse flow of water within the enlarged portions 28 and the turbulence resulting therefrom is what is commonly called and above-referred to as ram jet action. Accompanying this ram jet action is a compression of the air-water mixture entering the intake ports 34 as a result of the turbulent condition existing within the enlarged portions 28. Both the ram jet action and the aforementioned compression cause a drag which acts against the movement of the hydrofoil members 22 through the water. While the turbulent air-water mixture is desirably compressed thereby allowing into the neck portion 26 and the manifold 62 substantially all water, the drag resulting from this compression and the ram jet action is desirably minimized. On the other hand, since some compression of the turbulent air-water mixture is desirable, the ram jet action cannot altogether be eliminated. Ram jet action, therefore, is resent at the higher boat velocities. At extremely high boat velocities, ram jet action may result in the development of turbu lence not only within the enlarged portions 28 but also immediately in front of the enlarged portions 28 thereby creating a turbulent flow pattern extending for a finite distance on both sides of the intake port 34.

As shown in FIG. 1, whenever the boat 10 acquires a certain velocity, the hull 12 is lifted out of the water entirely leaving only the enlarged portions 28 of the respective hydrofoil members 22 in the water. Since the entire hull 12 is out of the water, the exhaust duct 20 of the pump 18 is also out of the Water and the stream 100 discharging from the duct 20 extends rearwardly of the boat for an appreciable distance above the surface of the water. Thus, the only drag occurring on the boat and at the higher operating speeds is the drag occurring from the hydrofoil members 22 themselves. For this reason, the reduction in the drag by means of adjusting the size of the intake ports as above-described is substantial and permits higher velocities to be obtained by the boat 10 than heretofore possible.

In the specific embodiment illustrated, the operation of the pump-motor combination 88 either expands or contracts each of the toroidal members 52 by the same amount. However, in a specific embodiment, each of the inlet and

exhaust tubes

54 and 56 could be provided with a valve therein (not shown) for selectively adjusting each of the respective intake ports of the respective hydrofoil members 22 independently of the others.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What is claimed is:

1. In combination, a hull having a longitudinal axis and a bottom, an engine mounted in said hull, a pump mounted in said hull and having inlet and exhaust ducts, said pump being operatively connected to said engine, means including said exhaust duct for propelling said hull in response to operation of said engine and pump, a plurality of hydrofoil members secured to said hull and depending below said bot-tom, each hydrofoil member having an enlarged portion at the distal end thereof and a neck portion extending between said enlarged portion and said hull, said enlarged portions and neck portions each being hollow, said enlarged portions each having an open end facing in a direction opposite that which said exhaust duct faces thereby forming an intake port, a manifold device mounted in said hull and connected to said pump inlet duct, said manifold device extending between the respective neck portions of said hydrofoil members and interconnecting each of the same with said inlet duct of said pump, each of said hydrofoil members and said manifold device being a continuous and smoothly shaped conduit extending between the respective intake ports and said pump inlet duct, and means within each of said enlarged portions of said hydrofoil members for selectively controlling the size of the respective intake ports whereby laminar flow of water to said pump may be emphasized over turbulent flow.

2. The combination of claim 1 wherein each of said enlarged portions of said hydrofoil members further comprises a rigid exterior shell and a flexible, self-supporting and resilient interior liner mounted therein, said liner having opposite ends, one of said liner ends being secured to said shell adjacent to said open end, the other of said liner ends being secured to said neck portion of the same hydrofoil member, said liner connecting said open end with the interior of the last-mentioned neck portion, said liner defining an annular space between said liner and shell, said liner being free to resiliently move away from said shell intermediate said liner ends, a resiliently expandable and generally toroidal member positioned in said annular space, and wherein said means includes said liner, said toroidal member and a second means for selectively expanding and contracting said toroidal member to move said liner radially away from said shell an equal distance measured along each radial line of direction.

3. The combination of claim 1 wherein each of said enlarged portions is streamlined in the general direction of said hull axis.

4. In combination, a hull having a longitudinal axis and a bottom, an engine mounted in said hull, a pump mounted in said hull and having inlet and exhaust ducts, said pump being operatively connected to said engine, means including said exhaust duct for propelling said hull in response to operation of said engine and pump, a hydrofoil member secured to said hull and depending below said bottom,

said member having an enlarged portion at the distal end thereof and a tubular neck portion extending between said enlarged portion and said hull, means within said hull for connecting said tubular neck portion to said inlet duct of said pump, said enlarged portion having an open end facing in a direction opposite that which said exhaust duct faces thereby forming an intake port, said enlarged portion having a rigid exterior shell and a flexible, self-supporting and resilient interior liner, said liner being secured to and extending between said shell adjacent to said open end at one of said liner ends and said neck portion at the other of said liner ends, said liner defining a smoothly shaped conduit with said neck portion and an annular space between said shell and liner, a resiliently expandable and generally toroidal, hollow member positioned in said annular space, a pump and fluid reservoir means mounted in said hull and connected to said toroidal member for selectively enlarging and contracting the same, said toroidal member being in contact with both said shell and said liner intenmediate said opposite lliner ends, said liner being selectively mowable radially inwardly of said shell from a normal position at the urging of said toroidal member in response to operation of said pump and fluid reservoir means, said liner being resiliently returned to said normal position when said toroidal member is fully contracted, whereby the size of said port can be controlled.

5. The combination of claim 4 wherein said toroidal member is made of rubber-like material, and said pump and fluid reservoir means comprises a tank and an air compressor.

6. In combination, a hull having a longitudinal axis and a bottom, an engine mounted in said hull, a pump mounted in said hull and having inlet and exhaust ducts, said pump being operatively connected to said engine, means includ-v ing said exhaust duct for propelling said hull in response to operation of said engine and pump, a hydrofoil member secured to said hull and depending below said bottom, said hydrofoil member being hollow and having an opening adjacent the distal end thereof, said hydrofoil member being connected to said inlet duct within said hull, and means within said hydrofoil member and said hull for selectively and variably restricting the flow therethrough.

7. The combination of claim 6 wherein said hydrofoil member further comprises a rigid exterior shell and a movable interior liner mounted in said shell, said liner extending from said open end for a partial length of said hydrofoil member and defining with said hydrofoil member a, smoothly shaped, continuous conduit between said opening and said pump; and wherein said means includes said liner and a second means Within said hydrofoil member and said hull for moving said liner towards and away from said shell.

References Cited by the Examiner UNITED STATES PATENTS 2,409,433 10/1946 Hunter 230-114 FOREIGN PATENTS 829,174 6/1938 France.

MILTON BUCHLER, Primary Examiner.

ANDREW H. FARRELL, Examiner.

Claims

1. IN COMBINATION, A HULL HAVING A LONGITUDINAL AXIS AND A BOTTOM, AN ENGINE MOUNTED IN SAID HULL, A PUMP MOUNTED IN SAID HULL AND HAVING INLET AND EXHAUST DUCTS, SAID PUMP BEING OPERATIVELY CONNECTED TO SAID ENGINE, MEANS INCLUDING SAID EXHAUST DUCT FOR PROPELLING SAID HULL IN RESPONSE TO OPERATION OF SAID ENGINE AND PUMP, A PLURALITY OF HYDROFOIL MEMBERS SECURED TO SAID HULL AND DEPENDING BELOW SAID BOTTOM, EACH HYDROFOIL MEMBER HAVING AN ENLARGED PORTION AT THE DISTAL END THEREOF AND A NECK PORTION EXTENDING BETWEEN SAID ENLARGED PORTION AND SAID HULL, SAID ENLARGED PORTIONS AND NECK PORTIONS EACH BEING HOLLOW, SAID ENLARGED PORTIONS EACH HAVING AN OPEN END FACING IN A DIRECTION OPPOSITE THAT WHICH SAID EXHAUST DUCT FACES THEREBY FORMING AN INTAKE PORT, A MANIFOLD DEVICE MOUNTED IN SAID HULL AND CONNECTED TO SAID PUMP INLET DUCT, SAID MANIFOLD DEVICE EXTENDING BETWEEN THE RESPECTIVE NECK PORTIONS OF SAID HYDROFOIL MEMBERS AND INTERCONNECTING EACH OF THE SAME WITH SAID INLET DUCT OF SAID PUMP, EACH OF SAID HYDROFOIL MEMBERS AND SAID MANIFOLD DEVICE BEING A CONTINUOUS AND SMOOTHLY SHAPED CONDUIT EXTENDING BETWEEN THE RESPECTIVE INTAKE PORTS AND SAID PUMP INLET DUCT, AND MEANS WITHIN EACH OF SAID ENLARGED PORTIONS OF SAID HYDROFOIL MEMBERS FOR SELECTIVELY CONTROLLING THE SIZE OF THE RESPECTIVE INTAKE PORTS WHEREBY LAMINAR FLOW OF WATER TO SAID PUMP MAY BE EMPHASIZED OVER TURBULENT FLOW.