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Contactless centrifugal pumpRelated Patent Categories: Pumps, Motor Driven, Electric Or Magnetic Motor, Pump Magnetically Coupled To Rotary DriveContactless centrifugal pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070183908, Contactless centrifugal pump. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] This invention relates to the field of centrifugal pumps and in particular to a frictionless or contactless centrifugal pump. BACKGROUND OF THE INVENTION [0002] Contactless centrifugal pumps are known in the prior art. [0003] One known type of contactless centrifugal pump has a one-piece rotor and impeller including several permanent magnets inside the rotor. About the outer circumference of the casing that surrounds the impeller are two layers (top and bottom) of electromagnets, and a corresponding number of gap detection sensors. The upper layer of electromagnets uses the sensor signals to adjust the repulsion and attraction force of each electromagnet, to set the gap between the rotating rotor and the casing, as well as the vertical position. The lower layer of electromagnets is powered by an alternating current, causing the rotor to rotate. These are driven by a driver, which contains a micro CPU. In the course of stopping, as the rotor decelerates it can be attracted to and touch the electromagnet's core, causing wear. Additionally, this pump is structurally complex, making maintenance relatively difficult for persons other than specialists. Moreover, only relatively small capacity pumps (under 1 KW) of this type are typically made, and this type of pump is relatively expensive when compared to other pumps. [0004] Another known type of contactless centrifugal pump is described in Japanese Patent Publication No. 2005-090478, which is illustrated in FIG. 19 of this disclosure. In this pump, the impeller 40 is directly connected to a metal torque cylinder 41, and is able to rotate within a "can" structure 35. By rotating the magnets on the inside and outside of the can with a motor 37, rotational force is generated in the torque cylinder, which causes rotation thereof. As the impeller is free, and the casing outflow 32 is towards the top of the structure, the liquid pressure within the casing 30 is such that P1<P2. Accordingly, the impeller will float upwards and the center of the impeller O2 can become higher than the center of the casing O1. In order to keep the difference between P1 and P2 at a minimum, the inner wall 31 is attached to the casing. However, when adjusting flow volume and discharge head, keeping P1 and P2 balanced is difficult. As the impeller rises, the torque cylinder can become caught on the can structure 35. As the impeller tilts, the impeller touches the casing at points Q1 and Q2, and the can and torque cylinder touch at points Q3 through Q6. On the inner surface of the casing, wedge devices 33,34 are attached, however when the impeller is tilted, their repulsive force is sharply decreased. (40-L, 41-L) show the position of the impeller and torque cylinder when they are tilted. Moreover, since the torque cylinder is cylindrical in shape, the magnets 36 must be attached to a cylindrical yoke, placing limits on both the number and size of magnets and the radius of effect (RD) to the impeller. Therefore the impeller output is constrained. Also, since the discharge mouth is directly connected to the inner surface of the can, the discharge pressure is equal to the internal pressure. Since the can has electromagnetic material property and thickness constraints placed on it, and pressure resistance constraints thereon, ultimately there are discharge head constraints. SUMMARY OF THE INVENTION [0005] A centrifugal pump for use with a liquid forms one aspect of the invention. This pump comprises a hollow casing arrangement, a rotor and a magnet arrangement. The hollow casing arrangement defines an interior, an axis intersecting the interior, an intake port for receiving said liquid in use and communicating same to said interior and a discharge port communicating with the interior. The rotor is positioned in said interior and is rotatable about said axis in spaced relation to said hollow casing arrangement. The rotor includes a drive member; a shaft extending axially from the drive member; and an impeller coupled to said drive member by said shaft for rotation therewith and adapted to cause fluid from said interior to be ejected through said discharge port upon said rotation. The magnet arrangement is disposed outside said interior and is adapted to drive rotation of said drive member about said axis in use through the creation of a rotating magnetic field. [0006] A centrifugal pump for use with a liquid and a motor forms another aspect of the invention. The pump comprises a hollow casing arrangement, a rotor and a magnet arrangement. The hollow casing arrangement defines an interior, an axis intersecting the interior, an intake port for receiving said liquid in use and communicating same to said interior and a discharge port communicating with the interior. The rotor is positioned in said interior and is rotatable about said axis in spaced relation to said hollow casing arrangement. The rotor includes an impeller adapted to cause fluid from said interior to be ejected through said discharge port upon said rotation. The magnet arrangement is disposed outside said interior, is coupled to said motor in use and is adapted to drive rotation of said rotor about said axis in use through the creation of a rotating magnetic field. The rotor and casing arrangement are adapted such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said hollow casing arrangement. [0007] According to other aspects of the invention, the impeller may be a closed impeller. As well, the hollow casing arrangement may include: a central casing defining a hole through which the shaft extends; a front casing defining, in combination with the central casing, a portion of the interior in which the impeller is positioned; and a rear casing defining, in combination with the central casing, a portion of the interior in which the drive member is positioned. Additionally, in use, the intake port may be horizontally disposed relative to said impeller and the discharge port may be upwardly disposed relative to said impeller. [0008] According to another aspect of the invention, the rotor and casing arrangement may be shaped such that: a first portion of the space between the rotor and the casing arrangement, in use, measured radially, undulates in magnitude around the impeller for stabilizing the rotor against radial movement; and a second portion of the space between the rotor and the casing arrangement, in use, measured axially, undulates in magnitude around the impeller for stabilizing the rotor against axial movement. [0009] According to other aspects of the invention, measured radially, in the direction of rotation of the rotor, in each undulation in the first portion the space between the rotor and the casing arrangement may gradually decrease and then quickly increase. As well, measured axially, in the direction of rotation of the rotor, in each undulation of the second portion the space between the rotor and the casing arrangement may gradually decrease and then quickly increase. [0010] According to other aspects, the impeller may have projecting from axially opposite sides thereof a pair of circular flanges, arranged coaxial with the axis; the casing may have defined therein a pair of circular channels in which the flanges rotate; the channels may have defined therein a plurality of first wedge-shaped protuberances; and the spaces between the flanges, channels and first wedge-shaped protuberances may define the first portion. [0011] According to another aspect of the invention, the first wedge-shaped protuberances may be circumferentially spaced-apart from one another and disposed radially outwardly from the flanges. [0012] According to another aspect of the invention, the casing arrangement may have defined thereon, on axially opposite sides of and in spaced relation to the impeller, a plurality of second wedge-shaped protuberances; and the spaces between the impeller and the second wedge-shaped protuberances may define the second portion. [0013] According to another aspect, the second wedge-shaped protuberances may be formed on a pair of annular inserts fitted in hollows formed, respectively, on the front and central casing. [0014] According to another aspect of the invention, the rotor and casing arrangement may be shaped such that a third portion of the space between the rotor and the casing arrangement, in use, measured radially, undulates in magnitude around the drive member for stabilizing the rotor against radial movement. [0015] According to another aspect of the invention, measured radially, in the direction of rotation of the rotor, in each undulation of the third portion the space between the rotor and the casing arrangement may gradually decrease and then quickly increase. [0016] According to another aspect of the invention, the drive member may have projecting in an axial direction therefrom a circular flange, arranged coaxial with the axis; the casing arrangement may have defined therein a circular channel in which the flange rotates in use; the channel may have defined therein a plurality of first wedge-shaped protuberances; and the space between the flange, channel and first wedge-shaped protuberances may define the third portion. [0017] According to another aspect of the invention, the first wedge-shaped protuberances may be circumferentially spaced-apart from one another and disposed radially outwardly from the flange projecting from the drive member. [0018] According to another aspect of the invention, said adaptation of the rotor and casing arrangement, such that said liquid supports said rotor in use for rotation substantially about said axis in spaced relation to said hollow casing arrangement, may comprise: a first wedge device which arrests radial translation of the rotor in use; and a second wedge device which arrests axial translation of the rotor in use. [0019] According to another aspect of the invention, the pump may further comprise a first wedge device which arrests radial translation of the rotor in use; and a second wedge device which arrests axial translation of the rotor in use. [0020] According to other aspects of the invention, the shaft may have positioned thereon at least one wing for arresting liquid flow from the impeller towards the drive member in use. [0021] According to another aspect of the invention, at least one wing may be a a spiral wing. Continue reading about Contactless centrifugal pump... Full patent description for Contactless centrifugal pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Contactless centrifugal pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Contactless centrifugal pump or other areas of interest. ### Previous Patent Application: Electronically commutated motor with bearing chamber defined by opposing abutment surfaces Next Patent Application: Vacuum pump Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Contactless centrifugal pump patent info. 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