Improvements in mixing or pumping devices

Abstract

 A mixing or pumping device in which a plurality of rotor blades (13) are mounted on a rotor shaft (7) and disposed within a housing (3). The rotor shaft is supported in a first bearing (35,37) adjacent to the housing and a second bearing (39,41) which is located between the first bearing and an end of the shaft which, in use, is coupled to a motor for driving the shaft. Conduit means (51) extend from the housing to the second bearing, the conduit means including a section (43) which bypasses the first bearing. In use, material is drawn into the housing in an axial direction and forced radially outwardly by the rotating blades. Other material within the housing is forced along the conduit means to the second bearing, where it serves as a lubricant.

Description

[0001] This invention relates to mixing or pumping devices.

[0002] Known devices for mixing material within a vessel or pumping material from a vessel include a motor which is mounted above the vessel and a rotor element and a housing which depend from the motor. The rotor element comprises a plurality of rotor blades secured to a lower end of a shaft which has its upper end coupled to an output shaft of the motor. The housing is supported by pillars which extend downwardly into the vessel from the motor casing.

[0003] For devices which employ a shallow mixing or pumping vessel and a short rotor shaft, lateral movement is reduced by supporting the shaft at or near its lower end, in which case a bearing is provided between the shaft and the housing of the device. For deeper vessels and longer shafts it is desirable to provide an additional support between the housing and the motor, in which case a second bearing is required.

[0004] The first, or lower bearing is immersed throughout mixing or pumping and is lubricated by material which is forced upwardly by the rotating element. The second, or upper bearing may be above the level of material within the vessel, however, and in any event the path for material from the rotor element to the upper bearing is effectively blocked by the lower bearing.

[0005] According to the present invention a mixing or pumping device comprises a plurality of rotor blades disposed within a housing and supported by an elongated rotor shaft, first bearing means which are disposed between the rotor shaft and support means therefor at a location adjacent to the housing, second bearing means which are disposed between the rotor shaft and the support means at a location between the first bearing means and an end of the shaft which is remote from the rotor blades and, in use, is coupled to an output shaft of a motor, and conduit means which extend from the housing to the second bearing means and which comprise a section which is located radially outwardly of, and serves to bypass, the first bearing means, the rotor blades being adapted, when they are immersed in material within the vessel and the rotor shaft is rotated, to cause material to be drawn in an axial direction into the housing and to force material within the housing in a radially outwardly direction, whilst other material within the housing is forced along the conduit means to the second bearing means, there to provide a lubricating action.

[0006] The support means for the rotor shaft may comprise a tubular member which is coaxial with the shaft, the first and second bearing means being disposed between the shaft and respective opposite ends of the tubular member. In this case, the space between the rotor shaft and the tubular member may form a further section of the conduit means.

[0007] Suitably, communication between the housing and the conduit means may be effected via an aperture in an axially outer end of the housing and guide means may be provided within the housing for directing material within the housing towards the said aperture. The guide means may comprise a cylindrical guide element disposed coaxially of the rotor shaft and radially outwardly of the volume swept out by the rotor blades.

[0008] The rotor blades may be secured to one side of a circular rotor plate which is mounted on the rotor shaft, and aperture means may be formed in the plate so that material within the housing can move through the plate to the conduit means.

[0009] The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a side elevation of a pumping device according to the invention;

Figure 2 is a vertical section of a part of the device of Figure 1; and

Figures 3 to 5 are scrap sectional views of modified forms of the device shown in Figures 1md 2.

[0010] Figures 1 and 2 of the drawings show a device according to the invention for pumping material, which may be a liquid or a mixture of a liquid and a solid, out of a deep vessel. The device includes a rotor element 1 and a housing 3 for the rotor element and, in use, depends from a motor 5 mounted above the pumping vessel (not shown).

[0011] The rotor element 1 of the present device, includes an elongated rotor shaft 7 of length sufficient for the shaft to extend downwardly from the motor 5 to a location adjacent the bottom of the pumping vessel. The shaft 7 is made in two sections which are releasably coupled together by a coupling 9.

[0012] At its upper end the rotor shaft 7 is adapted for coupling to an output shaft of the motor 5. Secured to a lower end of the shaft 7 is a circular plate 11 which is disposed coaxially of the shaft. Four rotor blades 13 are secured to a lower side of the rotor plate 11, each blade 13 being disposed in a vertical plane, perpendicular to the rotor plate 11, and each extending inwardly from the periphery of the plate to a location two-thirds of the way towards the axis thereof.

[0013] The housing 3 of the device includes a first member which forms a generally cylindrical side wall 15 and a lower end wall 17 thereof and a second member in the form of a circular top plate 19. Four pillars 21 support the housing 3 below the motor 5 in a position coaxially of the rotor shaft 7, each pillar 21 being secured to the motor casing at its upper end and being secured to the top plate 19 of the housing 3 at its lower end.

[0014] An inlet 23 to the housing 3 is formed by a central aperture in the lower end wall 17. An outlet 25 from the housing 3 is formed by an aperture in the top plate 19, this outlet being located radially outwardly of the volume swept out by the rotor blades 13 when the device is in use. A curved guide member 27 is provided in the space within the housing 3 which is immediately below the outlet 25, for the purpose of guiding material upwardly towards the outlet. An outlet pipe 29 extends upwardly from the outlet 25 to a vertical location adjacent the motor 5 and above the top of the pumping vessel.

[0015] The rotor shaft 7 extends downwardly from the motor 5 to the rotor element 1 via a central aperture 31 in the top plate 19 of the housing 3. Support means for the lower end of the shaft 7 include a tubular member 33 which has a short tubular insert 35, formed with an external flange, welded to its lower end. A lower end of the insert 35 is fitted into the central aperture 31 in the top plate 19 and the member 33 extends upwardly therefrom, coaxially of the shaft 7. A flanged bush 37 which is into a central bore in the insert 35 provides a bearing surface for the shaft 7. Additional support for the rotor shaft 7 is provided at a location adjacent to an upper end of the member 33 and a short distance below the coupling 9 between upper and lower sections of the shaft 7. A second bush 39, fitted into a flanged insert 41 at the upper end of the member 33, serves as a second bearing for the shaft 7.

[0016] Extending upwardly from the pump housing 3 to the second bearing 39 are conduit means along which material for lubricating the bearing 39 is conveyed.

[0017] The conduit means include a lower bypass section 43 which includes the space between the tubular member 33, a cylindrical element 45 which is disposed coaxially of and radially outwardly of the member 33 and has its lower ends welded to the top plate 19 of the pump housing 3, and an annular plate 47 which is located between the member 33 and an upper end of the cylindrical element 45. The cylindrical element 45 has an internal diameter smaller than the diameter of the volume swept out by the rotor blades 13 when the device is in use and inlets to the conduit means, which are also included in the bypass section 43, are formed by a series of apertures 49 in the top plate 19 of the housing 3. Each aperture 49 has a radial location intermediate those of the member 33 and the cylindrical element 45.

[0018] A further upper section 51 of the conduit means is formed by the space between the rotor shaft 7 and the member 33, communication between the upper section 51 and the lower section 43 being provided by a series of apertures 53 in the member 33.

[0019] To assist in guiding material within the pump housing 3 upwardly into the conduit means, guide means in the form of a cylindrical guide element 55 are provided within the housing 3, coaxially of a rotor shaft 7. The guide element 55 has an external flange at its upper end and this flange is secured to the undersurface of the top plate 19 of the housing 3. From the top plate 19 the guide element 55 extends downwardly to a vertical location adjacent the lower surface of the rotor plate 11. Between the guide element 55 and the rotor plate 11 there is a clearance of approximately 5 thou. ins.

[0020] Further assistance in urging material upwardly towards the conduit means is provided by a series of four holes 57 in the rotor plate 11. The holes 57 are so arranged that each in.turn moves through positions vertically beneath respective inlets 49 to the conduit means as the rotor plate 11 is rotated. Each hole 57 extends through the rotor plate 11 in a direction inclined to the axis of the rotor shaft 7.

[0021] The present device has a rotor shaft 7 which is approximately 5 feet 6 inches long and 1¼ inches in diameter and, in use, is rotated at 3,000 r.p.m. The housing 3 of the device has a diameter of 114 inches. The device can be used to pump material from a vessel which is approximately 6 feet deep and 3 feet 6 inches in diameter.

[0022] When the device is used for pumping liquid or a mixture of liquid and a solid from a deep vessel, the motor 5 is mounted above the vessel and the housing 3 and rotor element 1 are suspended from the motor, a short distance above the bottom of the vessel. Initially, the surface of material within the vessel is above the upper end of the second bearing 39 for the rotor shaft 7.

[0023] Upon rotation of the rotor blades 13 material at the bottom of the vessel is drawn upwardly into the pump housing 3 via the inlet 23 in the bottom wall 17 of the housing. Material within the housing 3 is urged in a radially outwardly direction.

[0024] Material which is below the cylindrical guide element 55 is forced radially outwardly beyond that element, towards the side wall 15 of the housing. The material has a circumferential component of velocity and impinges against the curved guide member 27, which serves to guide the material upwardly into the outlet pipe 29.

[0025] Further material is forced upwardly, through the holes 57 in the rotor plate 11 and into the space between the plate 11 and the top plate 19 of the pump housing 3. Some of this material moves into the space between the lower bearing 37 and the rotor shaft 7 and serves as a lubricant for the bearing 37. The remainder of the material is forced upwardly through the apertures 49 and travels via the lower section 43 and the upper section 51 of the conduit means to the upper bearing 39. This material provides lubrication of the upper bearing 39.

[0026] As pumping proceeds, the level of material in the vessel falls and eventually the level is below the upper bearing 39. This does not, however, affect the supply of material along the conduit means to lubricate the upper bearing 39.

[0027] In a first modification of the device described above, shown in Figure 3, a lower, bypass section of the conduit means is formed by a pipe 61 which extends upwardly from a single aperture in the top of a pump housing 63 to a single aperture in a tubular support member 65.

[0028] Figure 4 shows a second modification in which a bypass section 71 for the lower bearing is provided by axially extending holes 73 in an insert 75 at the lower-end of a tubular support member 77.

[0029] A further device, shown in Figure 5, has an upper bearing 81 supported by a support 83 which is independent of the support for a lower bearing 85. In this device the conduit means is formed by a pipe 87 extending from a pump housing 89 to the upper bearing 81.

[0030] A further modification of the device of Figures 1 aid 2 has a rotor element formed of blades directly secured to a rotor shaft, there being no rotor plate. With this device some material is forced upwardly towards the conduit via the spaces between the rotor blades.

[0031] In a further device according to the invention (not shown in the.,drawings) which is intended for mixing a solid with a liquid, disintegrating a solid within a liquid or homogenising a mixture of two liquids or a liquid and a solid, the pump housing 3, guide member 27, guide element 55 and outlet pipe 29 of the device shown in Figures 1 and 2 are replaced by a housing which serves as a stator element. This stator element has a cylindrical side wall whose internal diameter is only slightly greater than the diameter of the volume swept out by the rotating rotor blades 13. Apertures in the side wall serve as outlets from the stator element. In use of this device, material is subjected to mixing, disintegration and homogenisation as it moves radially outwardly between the rotor blades 13 and the stator element and through the outlets in that element. Other material is forced upwardly via apertures in the rotor plate to the space between the rotor plate and the top plate of the housing and then travels via the conduit means to the upper bearing, as described above.

[0032] Further devices according to the invention (not shown) have three or more axially spaced bearings for the rotor shaft, material for lubricating each bearing above the lowest being provided with conduit means for bypassing the or each bearing therebelow.

Claims

1. A mixing or pumping device comprising a plurality of rotor blades disposed within a housing and supported by an elongated rotor shaft, first bearing means which are disposed between the rotor shaft and support means therefor at a location adjacent to the housing, second bearing means which are disposed between the rotor shaft and the support means at a location between the first bearing means and an end of the shaft which is remote from the rotor blades and, in use, is coupled to an output shaft of a motor, and conduit means which extend from the housing to the second bearing means and which comprise a section which is located radially outwardly of, and serves to bypass, the first bearing means, the rotor blades being adapted, when they are immersed in material within the vessel and the rotor shaft is rotated, to cause material to be drawn in an axial direction into the housing and to force material within the housing in a radially outwardly direction, whilst other material within the housing is forced along the conduit means to the second bearing means, there to provide a lubricating action.

2. A device as claimed in claim-1, wherein the support means for the rotor shaft comprise a tubular member which is coaxial with the shaft, the first and second bearing means being disposed between the shaft and respective opposite ends of the tubular member.

3. A device as claimed in claim 2, wherein the space between the rotor shaft and the tubular member forms a further section of the conduit means.

4. A device as claimed in claim 3, wherein a cylindrical element is disposed coaxially of and radially outwardly of the tubular member and the bypass section of the conduit means comprises the space between a section of the tubular member and a section of the cylindrical element.

5. A device as claimed in claim 3, wherein a pipe extends from the housing to an aperture in a side wall of the tubular member, the pipe forming a part of the bypass section of the conduit means.

6. A device as claimed in claim 3, wherein the first bearing means are fitted into a central bore in a tubular insert which is fitted into one end of the tubular member, and the bypass section of the conduit means comprises at least one axially extending hole in the tubular insert.

7. A device as claimed in claim 1, wherein the bypass section of the conduit means comprises a pipe which extends from the housing to the second bearing means.

8. A device as claimed in any one of the preceding claims, wherein communication between the housing and the conduit means is effected via an aperture in an axially outer end of the housing, and guide means are provided within the housing for directing material towards the said aperture.

9. A device as claimed in claim 8, wherein the guide means comprise a generally cylindrical element which is disposed coaxially of the rotor shaft and radially outwardly of the volume swept out by the rotor blades.

10. A device as claimed in any one of the preceding claims, wherein the rotor blades are secured to one side of a circular rotor plate which is mounted on the rotor shaft, and aperture means are formed in the plate so that material within the housing can move through the plate to the conduit means.

Drawing