Patent Grant
9714573
The present invention relates to a rotor mechanism, in particular the present invention relates to a fully submersible rotor mechanism for moving fluid.
Pumps traditionally fall into two major groups: rotor-dynamic pumps and positive displacement pumps. Their names describe the method used by the pump to move fluid. Rotor-dynamic pumps are based on bladed impellers which rotate within the fluid to impart a tangential acceleration to the fluid and a consequential increase in the energy of the fluid. The purpose of rotor-dynamic pumps is to convert this kinetic energy into pressure energy in the associated piping system. A positive displacement pump causes a liquid or gas to move by trapping a fixed amount of fluid or gas and then forcing (displacing) that trapped volume into the discharge pipe. In both these types of pumps the fluid motion can be considered as moving in two dimensions along a plane.
No matter what type of pump is used, they all have one common design feature: the mobile part (rotor or turbine) is located in a rugged sealed case (stator). This design primarily increases the weight and size of the pump. The pump also requires many different parts such as bushings, gears seals etc. Given that a pump with high productivity Q (liter/min) requires a very high rotation speed (RPM) these additional mechanical parts result in a variety of different negative effects in terms of vibration, friction losses, noise, large power consumption and pulsation of the fluid stream which reduce the reliability of the pump.
A volumetric rotor machine has been developed for use in hydro mechanical engineering which does not require a waterproof case because the areas of high and low pressure are formed within the rotating units The rotor machine is formed of six rotors fixed in an axial direction on motionless, mutually perpendicular axes. Each rotor has the form of a truncated cone with two symmetric spiral recesses provided on the lateral surface of the rotor which acts to co-operate with the adjacent rotors. Channels of low pressure are formed in the mechanism by the periodic creation of a working chamber from the greater end faces of each of the rotors and channels of high pressure, by creating a working chamber from the small end faces of each of the rotors wherein the central part of the machine and the respective end faces form a cavity of high pressure and in one or more axes of the rotors, axial chambers are created. The mechanism is operated by being submerged in liquid and the surrounding liquid enters the mechanism from all sides in contrast to conventional pumps which as a rule, have a single inlet or suction port.
This volumetric machine was invented by A. V. Vagin in 1972 and was registered in the State Register of Inventions of the U.S.S.R. on Jan. 14 1975, as Invention Certificate 470190, now published as SU470190. As the original document is in Russian, we provide a translation of the description herein.
A general view of the volumetric rotor machine is shown in
The volumetric rotor machine contains six identical rotors, 1-6 each having the form of a truncated cone with two spiral recesses formed on the lateral surface. The recesses are formed such that their minimums lie coaxially with a conic rotor surface with an angle u1 at the top where
u1=arccos√⅔=35° 15′ (1)
and the edges lie coaxially with a conic rotor surface with an angle u2 at the top, where
u2=arccos√⅓=54° 15′ (2)
wherein the tops of both conic surfaces coincide with the top of a rotor. The lateral surface of a rotor in a spherical system of coordinates (r, u, φ) is described by the equations:
u=arccos(t/√3)
and
φ=arcsin[(t2+t−2)/√2(3−t2)]+φ0(r)
with 1≦t≦√2 (3)
where φ0(r) is any monotonous function defining a view of spiral deepening and edges on a lateral surface of a rotor.
In the equations (3) the dependence φ(u) is essential at r=constant and for the function φ(r) at u=constant, monotony is important only. In other words, the form of section of a rotor by spherical surface with the centre in its top is the key factor and a twisting of a rotor in a spiral around its axis at transition from one horizontal section to another, defined by the additive φ0(r), should only be monotonous. The form of the face surfaces of the rotors is not essential.
Plane CC is the main axial plane of a rotor. Mutually perpendicular axes 7 of rotors are crossed at one point. The tops of all six rotors lie on a point of crossing of the semi-axes. Mutual orientation of rotors means that axial planes of rotors 1 and 2 pass through axes of rotors 3 and 4, the main axial planes of rotors 3 and 4 pass through axes of rotors 5 and 6 and the main axial planes of rotors 5 and 6 pass through axes of rotors 1 and 2.
Spiral rotors on lateral surfaces of rotors adjoin on the length to deepening on lateral surfaces of the next rotors so that periodic creation of working chambers inside the device form a cavity of high pressure 8 and in one or several axes of rotors, channels of high pressure the through channels of the working medium are executed and connected with the cavity 8 and the exhaust 9.
Channels of low pressure 10 are formed by periodic disclosing of working chambers from the side of the greater end faces of rotors.
The device possesses one internal rotary degree of freedom—turn of one of the rotors around the axis on any angle necessarily entails turn of the other rotors around of the axes on the same angle. At turn of rotors around the axes, the chamber inside the device remains closed and its volume periodically changes.
In an initial position, such as that shown in
Positions φ=90° (see
Each quarter turn of the rotors in positions φ=45°, 135°, 225°, 315° gives a spasmodic change of volume of the working chamber from V up to Vmax. At one turn of the rotors in the chamber, the value of the volume which is forced or sucked away is equal to
ΔV=4(Vmax−Vmin) (4)
The attitude of ΔV to total volume of design V is equal
ΔV/V≈0.5 (5)
There are some major drawbacks in using this volumetric rotor machine. This design creates high pressure cavities between the internal (central cavity at end faces of rotors) and the external (outer faces of the rotors) spheres of the mechanism. The pressure zones generated create a systemic imbalance that drives fluid through the device creating a flow. As the device is configured, the gearing mechanism (the axles 7) is an integral part of the volume capture mechanism. This means that the device cannot retain pressure like other positive displacement pumps, by using seals in the contacted surfaces of the cavities. This limitation reduces the effectiveness of the design considerably as a large amount of pressure is lost through the mechanism and not imparted to the fluid in flow.
This is exacerbated by the fact that the gears 7 fill a major portion of the high pressure cavity 8. Cavity 8 is therefore not a free space cavity which would only contain fluid. Additionally, the high pressure cavity 8 is relatively small, as the radius of the inner surface 12 (see
Additionally, the device operates by being held stationary at the exhaust 9. Thus, the other five rotors can rotate about their axes 7, but the rotor containing the exhaust 9 must remain stationary as the exhaust line must be stationary. The arrangement is therefore limited to a single exhaust line. It has been found, in use, that the flow rate restrictions in the exhaust line increase back pressure through the mechanism resulting in the expulsion of fluids through the inlets which makes the entire mechanism inefficient.
The back pressure, coupled with the high pressure experienced in pulses through the mechanism also causes rapid wear and damage at the edges of the rotors.
DE19738132 to Jaitner describes a multi-element compression machine which has at least three elements rotating about fixed axles and with spiral interlocking surfaces which are out of contact to provide a minimum spacing. The elements rotate at a constant speed and generate new compression volumes which pass through the machine in a more laminar way than with conventional compression engines. No special seals are required for a high efficiency compression action.
Like Vagin, this machine also compresses the fluid which will therefore have the same disadvantages in back pressure.
U.S. Pat. No. 4,979,882 to the Wisconsin Alumni Research Foundation discloses a spherical rotary machine which may be embodied as a pump, internal combustion engine, compressor or similar other device includes an outer shell with a substantially spherical interior surface, an inner shell including a substantially spherical outer surface centered within the outer shell, and six rotary pistons located between the inner and outer shell. Each piston is rotatable about its own central axis, the six axes being orthogonally centered on the center of the machine. Each piston includes a top convex spherical surface conforming substantially in shape to and located adjacent to the spherical interior surface of the outer shell, a bottom concave spherical surface conforming substantially in shape to and located adjacent to the spherical outer surface of the inner shell, and an oval conical side surface which is substantially defined by lines which are substantially radial with respect to a point near the machine center. The oval side surface of any single piston at least nearly touches tangentially along generally radial lines the oval side surface of each of its four adjacent pistons so that any three pistons which are all adjacent to each other form a displacement chamber which varies in size as the pistons simultaneously rotate. Each piston is operably connected to a gear which is interconnected with the gears of the other pistons to regulate the relative positions of the pistons to ensure that all the pistons rotate with identical speed and direction with respect to the center of the machine. These gears may be located within or without the outer shell of the machine.
Again, like Vagin, this machine compresses the fluid and includes axles of the gearing mechanism which pass through and interrupt the high pressure cavity within the substantially spherical interior surface. In this way it has the same disadvantages as for Vagin. Additionally, there is no twist on any of the pistons, so the machine would not achieve movement of fluid from the outer surface through the exhaust as without the twist there is no means of fluid capture.
US 2006/0210419 to Searchmont LLC describes a rotary machine which can be either a pump or an internal combustion engine has a housing enclosing a plurality of rotor spindles lying on the surface of an imaginary cone for driving an output shaft positioned at the vertex of the imaginary cone. The spindles have a beveled gear on one end and engaging an output shaft and a conical bearing on the other end. Angled eccentric rotors are mounted to each spindle shaped to maintain tangential sliding contact with two adjacent rotors to form a compression or combustion chamber. A spherical version of a compressor or an engine uses a plurality of rotary pistons each of which is eccentrically mounted and forms a spherical segment. Each rotary piston is mounted for tangential sliding contact with at least two other rotary pistons to form a displacement chamber therebetween. The rotary pistons use a generally “tear drop” shape. A rotary pump has a housing having a manifold for distributing intake and exhaust air. The pump has a plurality of lobe shafts, each having an eccentrically mounted rotor attached thereto mounted in the housing to form a compression chamber in the middle of the rotor when the rotors are all in contact with each other during rotation.
Like the other prior art, this machine is designed to compress the fluid, as required of a combustion engine. The rotary pistons lack a twist angle and thus fluid capture is not achieved to move the fluid between an outer surface of the machine, to a central cavity and then via a port back to a position at the outer surface.
It is an object of the present invention to provide a rotor mechanism which obviates or mitigates at least some of the disadvantages of the prior art.
According to a first aspect of the present invention there is provided a rotor mechanism for use in moving fluid, the rotor mechanism comprising:
In this way, a large uninterrupted free space cavity is formed in the centre of the rotor mechanism which is not impinged by a gearing mechanism. This allows for transfer of a larger volume of fluid which reduces the likelihood of back pressure and allows a seal to be created between the moving rotors so that pressure is maintained as would be expected in a positive displacement pump.
Preferably, the rotor mechanism body is supported in an external frame. In this way, there is no requirement for an internal gearing mechanism and axles are not required to be mounted through the rotors. This provides a highly compact design which can be of low weight and small dimensions.
More preferably, the frame comprises a plurality of arcs. In this way, the outer surface of the body is left unobstructed for the transfer of fluid. Preferably, the frame supports the body on a plurality of bearings. In this way, the rotor units can move independently of the frame.
Preferably, at least two rotor units have a port through the rotor unit. In this way, multiple exhaust ports can be present which increases the exit volume and thereby further reduces the possibility of back pressure.
Preferably, each rotor unit is operable to co-operate with adjacent rotor units such that during rotation plural channels are created in which fluid is carried in one direction between the outer surface of the mechanism body and the central free space cavity. The direction of travel will be dependent on the direction of rotation of the rotors. Preferably, each rotation fills the channel and seals each end thereof to create a temporary chamber. In this way, a plurality of ports is temporarily created at the outer surface of the body. The temporary ports may act as input or output ports depending on the direction of rotation of the rotor units.
Preferably, each rotor unit has at least two lateral surfaces which are arranged to provide the rotor unit with a truncated double helix form. In this way, the truncated double helix form of the lateral surfaces of the rotor units provides an arrangement to create the channels.
Preferably the rotor mechanism is provided with six rotor units. In this way, the rotor mechanism can be designed around the three axes model of the prior art. More preferably, each rotor unit comprises a conical screw rotor, having an axis at right angles to adjacent rotor units and which is twisted at an angle over a length of a truncated cone. The angle provides the rotation angle of the double helix form of lateral surfaces. Preferably, each rotor unit has the same dimensions. In this way, the length and angle can be used to determine the volume of fluid through the channels and in the central cavity with respect to the radius of the outer surface of the body.
Preferably a radius of the inner surface of a rotor unit is greater than half a radius of an outer surface of a rotor unit. In this way, the radius of the free space cavity is greater than half the radius of the outer body so that fluid is not compressed in entering the free space cavity or restricted on exiting the port.
Preferably, the radius of the outer body and the length and twist angle of the rotor units are selected to substantially eliminate any fluid compression through the rotor mechanism. In this way, the mechanism acts as a positive displacement pump in contrast to the prior art mechanism. Additionally, the rotor mechanism can pump up to around half the volume of the outer body on a single rotation of the rotor units. In this way, a high capacity low pressure pump is formed.
Preferably, the radius of the outer body, the length and twist angle of the rotor units and dimension of the ports are selected to substantially equalize the volume of fluid travelling through the rotor mechanism. In this way, hydraulic losses due to large volumetric discrepancies creating high pressures are eliminated.
Preferably, a spiral edge of each rotor making up the free space central cavity, has a coil of just equal to 180 degrees in order to completely isolate the central cavity from the environment. In this way, the rotor mechanism can be considered as ‘not blown’ as compared to known designs of turbine and centrifugal pumps which are blown or have permeability.
In an embodiment, a first rotor unit is held stationary and the remaining rotor units rotate synchronously around three mutually perpendicular axis which converge at a central point of the central cavity of the rotor mechanism. In this way the rotor mechanism can operate in the same fashion as the prior art volumetric rotor mechanism, but can have additional exhaust ports to more efficiently move the fluid through the mechanism. This can provide a spherical high capacity low pressure submersible pump. Such a pump finds use as a bilge pump for sea vessels.
Preferably the rotor mechanism is further provided with a drive unit which in use, acts upon one of said rotor units operable to rotate in order to actuate and drive the rotatable rotor units. The drive unit may be any motor arrangement as known to those skilled in the art. The mechanism can be operated at very low values of RPM and thus a small motor unit having its drive shaft connected to an axis of a rotor unit can be used in contrast to the large two stage hydraulic pump arrangements of the prior art.
Alternatively, the drive unit may operate in the rotor mechanism by means of an electromagnetically induced rotation. One or more rotor units may include windings in the rotor or around an axis thereof, coupled with a magnetic source of opposing pole, an induced rotational force can be delivered by electrical supply to the windings. In this way, a very compact spherical high capacity low pressure pump is formed as either an AC or DC motor.
Alternatively, a spherical generator can be formed in which rotation of the rotor units is carried out by an external force and electricity is generated by moving the windings across the magnetic field. In this embodiment, fluid (or any method of imparting rotation) is input through the port in a rotor unit and exits through the temporary ports on the outer surface. This provides a spherical high capacity low pressure electrical generator. More preferably, the application of a fluid through a port induces rotation of a rotor unit which thereby operates the rotor mechanism.
Advantageously, one or more rotor units may include windings on an axis thereof with a core located within the windings, which by the application of a fluid through a port causes rotation of the rotor unit and windings to induce electrical flow at each core to provide a spherical turbine.
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawing of which:
Reference is initially made to
The rotor units 30 are solid elements in the form of a conical spiral arranged on an axis 31. The rotor units 30 are positioned such that the axis 31a-31f of each rotor unit 30 is at right angles to the axis 31a-31f of the adjacent rotor units. Each rotor unit 30 is arranged so as to cooperate with one another such that the petal shaped outer surface 32 of each rotor unit 30 is curved concavely out from the rotor mechanism 20 and contributes to the outer surface 22 of the rotor mechanism body 21. This is best seen in
Without an internal gearing structure 7, as in the prior art, the rotor units 30 are held together by use of a frame 50, illustrated in
On the rotor units 30 which do not include ports 40, a bearing axle 44 is fixed into the outer surface 32 of the rotor unit 30. The axle 44 does not extend through the rotor unit 30 and is only embedded sufficiently to turn with the rotor unit 30. Preferentially ports 40 face each other, when more than one is present. In this embodiment two are shown, but there may be up to six in i.e. one per rotor unit 30, if desired. Each arc section 52 has a twin set of bearing rings 64 arranged centrally and axially on the arc. The bearing rings 64 slide over the axles 44 and allow the axles 44 together with their attached rotor unit 30 to rotate independently of the frame 50.
By using pairs of bearing rings 60,64 at each of the six axes 31 of the rotor mechanism 20, the axes are cantilevered for support.
Each of the rotor units 30 is now considered in greater detail with
With reference first to
As can be seen from
With reference to
In use, the six rotor units 30 are located within the frame 50. In an embodiment of a submersible or bilge pump, a single port 40 is present and the connection 62 will be made to tubing to be routed overboard. On one axle 44, there will be located a DC motor to turn the axle into a drive shaft and cause rotation of the rotor unit 30 to which the axle 44 is affixed. A low rpm is all that is required as the motor is only turning the single rotor unit. The rotor mechanism body 21 in it's frame 50 is submerged in water.
The rotation of a single rotor unit 30 by the motor impels the other rotor units to turn synchronously about their axis 31. With reference now to
It will be appreciated that when three or more rotor units 30 are interlinked perpendicular to one another the driving functionality of the arrangement will act continuously with a driving edge 34′ acting on one rotor unit 30 for a 180° turn after which it will act on another adjacent rotor unit 30. As there are two driving edges 34′, 36′ per rotor unit 30 a continuous driving process through a rotation of 360° is achieved.
The interlocking helical form of rotor units 30a-f, when arranged to form the rotor mechanism 20 of
Referring back to
If each of the rotor units 30 are formed in such a manner that the spiral edge of each rotor unit 30 provides a coil at equal to 180 degrees at the closed point, then the internal cavity 42 is completely isolated from the environment 28. Such a design is referred to as ‘not blown’, which provides for the possibility of pumping at high pressure. This is in contrast to known designs of turbine and centrifugal pumps in braked conditions which are blown or have permeability. Preferentially, the radii of the central cavity 26 and body 21 is selected together with the length of rotor, angle of rotation and volume of outlet to provide near constant volume of fluid through the rotor mechanism so that back pressure is avoided. In particular, the radius of the central cavity 26 is made greater than half the radius body 21. This also reduces the pressure differential through the rotor mechanism so that the fluid is never compressed and prevents damage to the rotor units.
As detailed above with reference to a submersible or bilge pump, the rotor mechanism 20 can be driven by any external motor.
Further embodiments of the present invention are provided by incorporating a magnet and coil arrangement at the axes 44. An example of this embodiment is shown in
By applying an electric current to the windings 82, a magnetic field is generated which imparts a rotational force on the accompanying rotor unit 30. The corollary is also useful, in that if the rotors 30 are moved by any means of propulsion, the magnets 80 will rotate and the coils 82 will move through the magnetic fields of the magnets 80, establishing a current in the windings and thus creating electricity.
The principle advantage of the present invention is that it provides a rotor mechanism which does not require an enclosed waterproof housing.
A further advantage of the present invention is that it provides a rotor mechanism which does not compress the fluid as it moves through the mechanism.
A yet further advantage of the present invention is that it provides a pump achievable at very low values of RPM.
Further advantages of the present invention are realized in that it has a high compactness of design (low weight and small dimensions); low number of elements to give a simplicity in design and construction; low level noise; low level of vibration; constancy of stream of a pumped over product; small friction losses and small power consumption compared with pumps of similar productivity.
Modifications may be made to the invention herein described without departing from the scope thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1204111.7 | Mar 2012 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/GB2013/050527 | 3/4/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/132237 | 9/12/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4979882 | Wipf | Dec 1990 | A |
| 7625193 | Chadwick | Dec 2009 | B2 |
| 20060210419 | Chadwick, II | Sep 2006 | A1 |
| Number | Date | Country |
|---|---|---|
| 19738132 | Sep 1999 | DE |
| 1849958 | Oct 2007 | EP |
| 470190 | Jan 1975 | SU |
| Number | Date | Country | |
|---|---|---|---|
| 20150010413 A1 | Jan 2015 | US |
