EP2868928A1 - Pompe centrifuge et procédé de pompage d'une substance - Google Patents

Pompe centrifuge et procédé de pompage d'une substance Download PDF

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Publication number
EP2868928A1
EP2868928A1 EP20130190981 EP13190981A EP2868928A1 EP 2868928 A1 EP2868928 A1 EP 2868928A1 EP 20130190981 EP20130190981 EP 20130190981 EP 13190981 A EP13190981 A EP 13190981A EP 2868928 A1 EP2868928 A1 EP 2868928A1
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EP
European Patent Office
Prior art keywords
cavity
impeller
centrifugal pump
volute casing
medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP20130190981
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German (de)
English (en)
Inventor
Reijo Puittinen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sulzer Pumpen AG
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Sulzer Pumpen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sulzer Pumpen AG filed Critical Sulzer Pumpen AG
Priority to EP20130190981 priority Critical patent/EP2868928A1/fr
Publication of EP2868928A1 publication Critical patent/EP2868928A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
    • F04D7/04—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous
    • F04D7/045—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous with means for comminuting, mixing stirring or otherwise treating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/445—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/18—Rotors
    • F04D29/22—Rotors specially for centrifugal pumps
    • F04D29/2261—Rotors specially for centrifugal pumps with special measures
    • F04D29/2288—Rotors specially for centrifugal pumps with special measures for comminuting, mixing or separating

Definitions

  • the present invention relates to a centrifugal pump and a method of pumping a medium.
  • the present invention relates especially to a centrifugal pump having a novel impeller - volute casing construction.
  • the centrifugal pump and the method of the present invention are especially suitable for pumping fibrous paper or board making suspensions.
  • the main components having an influence on the pumping characteristics of a centrifugal pump are the volute casing or volute and the impeller.
  • the impeller is formed of a hub and working vanes attached to the hub.
  • the hub is provided with a central hole for fastening the impeller to the shaft of the pump.
  • the above described impeller i.e. the one having merely a hub and working vanes, is called an open impeller. If the hub is extended radially outwardly by means of a so called rear plate to which the working vanes are arranged at their rear edges, the impeller is called a semi-open impeller, i.e. the front edges of the working vanes being free or open.
  • the impeller is called a closed impeller.
  • the volute casing comprises normally a front wall of the pump starting from the suction inlet and continuing radially outwardly, substantially following the shape of the front edges of the working vanes of the impeller, to form a cavity to which the impeller pumps the medium to be pumped.
  • the cross sectional area of the cavity increases in the direction of rotation of the impeller up to the discharge outlet opening to which is normally arranged a tangential pressure outlet duct for discharging the medium further in the process.
  • the outlet duct is usually situated radially outside of the impeller for minimizing pressure losses. The point where the discharge flow separates from the flow continuing its circulation in the volute is called a cutwater.
  • the cavity has a wall the cross section of which is in a radial plane annular, sometimes almost circular, except for the opening at its inner section where the impeller feeds the pumped medium into the cavity.
  • the opening is, naturally, located to the radially innermost part of the volute.
  • volute casings There are two basic types of volute casings, namely single suction or double suction types.
  • a centrifugal pump When a centrifugal pump is of single suction type, it draws liquid from one axial side of the pump and pumps it radially out of the pump.
  • double suction pumps the pump draws the liquid from both opposite axial sides of the pump, and pumps the liquid radially out of the pump.
  • impellers too, i.e. the impellers are also single suction or double suction types.
  • the double suction impellers may also be open, semi-open or closed like the single suction impellers.
  • the dimensioning of the impeller in relation to the cavity of the volute casing is in prior art centrifugal pumps normally such that the impeller and especially the working vanes thereof, extend in radial direction at most into the above mentioned opening, but not any further.
  • the described structure is supposed to give the pump the best available efficiency and head.
  • centrifugal pumps Another problem found in prior art centrifugal pumps is, when pumping fibrous suspensions, the tendency of the fibers to form flocs, i.e. small groups of fibers attached to each other, in the suspension.
  • a further problem may be experienced as difficulties in pumping if the turbulence level in the spiral is not high enough. If such a pump is feeding paper making stock to the headbox and the flocs end up onto the wire of the paper machine, the flocs reduce the quality of the end product, and at their worst create holes in the web.
  • an object of the present invention is to develop a new type of a centrifugal pump and a method of pumping a medium capable of solving at least one of the above discussed problems.
  • Another object of the present invention is to develop such a novel centrifugal pump and a method of pumping a medium that reduces the pulsation level compared to the prior art centrifugal pumps.
  • a further object of the present invention is to develop such a novel centrifugal pump and a method of pumping a medium that reduces the tendency of floc formation.
  • a centrifugal pump for pumping a medium
  • the centrifugal pump having a shaft, an impeller on the shaft and a volute casing housing the impeller; the impeller having working vanes each having an outer edge and a front edge; the volute casing having a circumferentially extending cavity having a cross section formed by a wall; the wall having a rear wall section with a radially inner edge, an inner wall section with an inner edge and an opening for allowing medium pumped by the impeller to enter the cavity in radial direction directly from the impeller; the volute casing further having a cutwater radially outside of the impeller, the cutwater separating a pressure outlet duct from the cavity, the pressure outlet duct being located radially outside of the impeller wherein the cross section of the cavity is oval such that the cavity has wherein the oval cavity has a first axial end and a second axial end, the opening being located at the inner circumference of the first axial end, the
  • At least one of the objects of the present invention is fulfilled by a method of pumping a medium with a centrifugal pump of claim 1, wherein
  • centrifugal pump and the method of the present invention bring about several advantages in comparison to prior art centrifugal pumps. At least the following advantages may be listed:
  • FIG 1 is a general cross sectional illustration of a prior art centrifugal pump showing only the volute casing 10 and the impeller 30.
  • the components, i.e. the volute casing 10 and the impeller 30 have been shifted apart in axial direction such that their structure would be easier to comprehend.
  • the volute casing 10 comprises an inlet or suction opening 12 the inner surface of which is formed of a wear plate 14.
  • the wear plate 14 is a replaceable and axially adjustable annular plate that extends in the direction of the flow from the inlet opening towards a pressure outlet duct (not shown) in the outer circumference of the volute casing 10.
  • the purpose of the wear plate 14 is to protect the volute casing 10 itself when pumping such medium that tends to wear the components used for pumping.
  • the wear plate 14 is to be able to adjust the running clearance of the impeller. In other words, when the wear plate has worn to a certain extent, it may be moved closer to the impeller so that the running clearance of the impeller may be brought back to correspond to that of a new pump.
  • the wear plate 14 is not a necessary component of the volute casing 10, but the casing surface itself may be open to the medium to be pumped (see for instance Fig. 5 ).
  • the wear plate is normally used with open or semi-open impellers as a closed impeller itself (see for instance Fig. 7 ) has a front plate preventing the wear of the volute casing.
  • the volute casing 10 comprises further a cavity 16 into which the impeller pumps the medium via opening 19 and in which the medium to be pumped circulates (in the circumferential direction) before being discharged from the pump via the discharge or pressure outlet (not shown).
  • the cavity 16 of the volute casing 10 is substantially circular of its cross section and traditionally located immediately (radially) outside of the impeller 30 such that the medium may be pumped by the impeller via the opening 19 radially outwardly into the cavity without any additional restrictions. The same positioning applies to the pressure outlet duct of the volute casing, too, i.e.
  • the opening 19 is arranged in the centre region of the inner circumference of the cavity 16, whereby the cavity extends substantially symmetrically to both sides of the radial centreline plane of the opening 19.
  • the cavity 16 has an annular wall 18, starting from a rear wall section 20 or rather from an inner edge 22 thereof and terminating to an inner wall section 24 with an edge 26. The edges 22 and 26 leave the opening 19 therebetween via which the impeller pumps the medium into the cavity 16.
  • the edge 22 of the rear wall section 20 of the volute casing 10 defines a central rear opening 28 via which the impeller may be brought into the volute casing 10.
  • the volute casing may, however, be formed of several parts.
  • the front wall including the inlet or suction opening may be a part separate to the part forming the cavity.
  • the impeller 30 illustrated in Figure 1 is a so called semi-open impeller, i.e. having a hub 32 with a central opening/hole 34 for the shaft, working vanes 36 and a rear plate 38.
  • the working vanes 36 have a front edge 40, which is, over its entire length, facing the volute casing 10 and arranged, in an assembled centrifugal pump, at a certain distance from the volute casing 10 or (if used) from its wear plate 14, and a radially outer edge 42, which faces the opening 19 to the cavity 16 of the volute casing 10.
  • the rear plate 38 of the impeller 30 has an outer edge 44 which is arranged in close proximity of the inner edge 22 of the rear wall section 20 of the cavity 16.
  • the impeller has so called rear vanes, i.e. vanes at the rear side of its rear plate 38, the outer edge 44 of the rear plate 38 leaves a gap in both axial and radial direction between itself and the inner edge 22 of the rear wall section 20 of the cavity 16 for the medium pumped by the rear vanes to enter the cavity 16.
  • FIG 2 is a schematical axial cross sectional illustration of a single suction centrifugal pump in accordance with a preferred embodiment of the present invention.
  • the impeller 130 of the embodiment of Figure 2 is equal to the impeller 30 of Figure 1 , i.e. it is a semi-open impeller, and has the same elements, whereby the same reference numerals are used except that each of them is preceded by '1'.
  • the volute casing 110 is basically similar to the one shown in Figure 1 , in other words, its cross sectional area grows circumferentially, i.e.
  • volute casing 110 in the direction of the rotation of the impeller, and it is located immediately (radially) outside of the impeller 130 such that the medium may enter the cavity 116 via opening 119 without any additional restrictions.
  • the same approach applies to the pressure outlet duct of the volute casing 110, too, i.e. it extend to the entire axial width of the volute casing 110 and is positioned to depart tangentially from the cavity 116, whereby it is located at the same radial plane with the impeller 130 and the cavity 116.
  • the volute casing 110 has a few interesting differences.
  • the cross section of the cavity 116 is not any more circular or round as in prior art pumps, but it is oval.
  • the cross section of the cavity 116 or the volute casing is compressed or reduced in radial direction whereby it has expanded or increased in axial direction.
  • the word "oval” includes both elliptical and such substantially quadrangular shapes that have well-rounded corners for ensuring easy spiral circulation of the medium in the cavity 116.
  • An essential feature of the volute casing 110 or the cavity 116 of the present invention is that the opening 119 introducing the medium from the impeller to the cavity 116 is not located centrally at the inner circumference of the cavity 116, but at an axial end, or a first axial end, of the cavity. This means that the cavity 116 is located asymmetrically in relation to the radial centreline plane of the opening 119.
  • the above described construction of the volute casing ensures an efficient recirculation of the medium back to the impeller.
  • the overall diameter of the volute casing 110 is smaller than that of the volute casing 10 in the prior art Figure 1 .
  • the main reason for this structural feature is that the cross sectional area of the oval volute casing increases mostly in axial direction from the rear wall section towards the side of the inlet of the pump, i.e. asymmetrically in relation to the opening 119 arranged for the impeller and/or the medium to be pumped in the volute casing.
  • the cross sectional area of the volute casing grows equally in both radial and axial directions, i.e. symmetrically in relation to the opening leading from the impeller to the volute casing.
  • the rear wall section 120 of the cavity 116 of the volute casing 110 does not any more extend to the entire radial width of the cavity 116 as it did in the prior art volute casing 10 of Figure 1 , but the impeller rear plate 138 extends radially outwardly such that it, in a way, forms a part of the rear wall of the cavity 116.
  • the working vanes 136 of the impeller 130 are made to extend in radial direction into the cavity 116 via the opening 119.
  • the rear plate 138 of the impeller 130 i.e. its radially outer edge 144 extends in radial direction to the same diameter as the working vanes 136.
  • the pump rear wall (not shown) may be made to fill the gap.
  • the opening 128 in the rear of the volute casing 110 has at least the same diameter (in practice slightly larger) than that of the impeller 130 at its largest, i.e. that of the outer edges 142 of the working vanes 136 or that of the outer edge 144 of the rear plate 138, whichever extends radially farther from the axis of the impeller 130.
  • the working vanes 136 of the impeller 130 extend radially farther away from the axis than the edge 126 of the inner wall section 124 of the annular wall 118 of the cavity 116 of the volute casing 110.
  • the diameter of the edge 126 of the inner wall section 124 is 80 - 90 % of the diameter of the impeller, i.e. that of the outer edges 142 of the working vanes, to be more specific.
  • the edge 126 of the inner wall section 124 may be located not only as an integral part of the volute casing but also as the outer edge of the wear plate 114.
  • the outer rim of the wear plate 114 may be considered to form a part of the inner wall section 124.
  • the edge 126 of the annular wall 118 of the cavity 116 of the volute casing 110 extends to the side plate or wear plate 114, and, in fact, is a part thereof.
  • the edge 126 of the annular wall 118 which may be a part of the side plate 114 or integrated to the volute casing 110, may form a kind of a deflector directing the recirculating flow more or less in outward direction and not only axially towards the impeller 130.
  • the edge 126 forms a deflector it means structurally that the edge 126 extends deeper into the cavity 116 or radially more outwardly than the radially innermost surface of the inner wall section 124.
  • the fourth difference is the reduced radial distance between the inlet opening 112 and the cavity 116 in the volute casing 110, which is due to the reduced overall diameter of the volute casing 110 and the existence of the same inlet opening 112 diameter.
  • the distance is so small that the wear plate 114 may be easily extended to cover the entire distance.
  • the wear plate may also be made shorter, i.e. in line with the teachings of Figure 1 , for instance, or the wear plate may be entirely left out (see for instance Fig. 5 ). This depends mainly on the intended use of the pump.
  • FIGs 3 and 4 illustrate in more detail the differences between the prior art centrifugal pump ( Figure 3 ) and the centrifugal pump of the present invention ( Figure 4 ).
  • the Figures show clearly how the impeller vanes 136 of the impeller 130 of the invention, i.e. those of Figure 4 extend in radial direction deep in the cavity 116, whereas vanes 36 of the prior art pump do not extend in the cavity 16 at all, but just feed the pumped medium into the cavity 16.
  • the outer edges 142 of the working vanes 136 of the present invention are located radially farther from the axis of the pump than the inner edge 126 of the inner wall section 124 of the wall 118 of the cavity 116.
  • the front edge 140 of the working vanes 136 follows the inner surface of the volute casing, or the wear plate 114, or both with a small running clearance up to the inner edge 126 of the inner wall section 124, and extends radially outwardly therefrom into the cavity 116. This is especially important in view of the operation of the pump of the present invention, as explained in more detail in the following.
  • the impeller of the centrifugal pump feeds the pumped medium radially outwardly in the volute casing, whereby the medium starts to follow the inside surface of the wall 18/118 of the volute casing 10/110.
  • the pumped medium advances along a spiral path in the cavity 16/116 of the volute casing up to the cutwater (shown in Figure 6 ), which is located just radially outside of the impeller in the opening 19/119.
  • the both circumferentially and spirally flowing medium is divided such that a part of the medium continues to follow the spiral path in the cavity 16/116 and another part is discharged from the pump via the pressure outlet.
  • the medium entering substantially tangentially to a first axial end 116' of the oval cavity 116 is efficiently guided to a spiral flow along the wall of the cavity to the second axial end 116" of the cavity and from there back to the first axial end 116' of the cavity into communication with the working vanes.
  • the spiral flow is much more efficient in the pump of the present invention, as in prior art pumps the flow enters the cavity along the diameter thereof and not tangentially whereby an efficient spiral flow cannot be formed as two counter rotating flows are formed in the spiral.
  • the working vanes 136 of the present invention extend into the cavity 116, they increase the rotational velocity of the spiral flow in the cavity 116, as a part of the medium rotating already in the cavity reaches the vanes, the front edges 140 of the working vanes 136 to be more specific, i.e.
  • the vanes 136 when rotating inside the cavity 116, subject the spirally rotating medium flow to strong shear forces, especially by means of their front edges 140.
  • the shear forces may be utilized in several different ways. An option is to introduce one or several chemicals (as discussed later in connection with Figure 7 ) into the cavity 116, i.e. to the spiral flow advancing towards the working vane region, where the strong shear force field is able to mix the chemical/s efficiently with the pumped medium.
  • the shear forces may also be utilized when pumping medium that includes flocs or tends to allow floc formation, the medium being paper making stock, for instance. In such a case, the flocs are loose groups of fibers that, if entering the wire section of the paper making machine, reduce the quality of the end product. Now that the medium, for instance paper making stock, is subjected to strong shear forces by the front edges 140 of the working vanes 136 the shear forces break the already formed flocs and prevents the formation of any new flocs.
  • the above described impeller - volute casing configuration improves also the struggle against the pulsation. It has been understood for a long time that the pulsation is for the most part caused by, on the one hand, the pressure difference over the working vane, and, on the other hand, the abrupt change in velocity caused by a working vane passing the blunt cutwater.
  • the pressure difference over the working vane is considerably reduced due to the more efficient spiral or recirculating flow at the outer edge area of the working vanes of the impeller.
  • the impeller is at one side thereof open to the spiral flow is that the spirally advancing or recirculating flow is able to enter the space between the working vanes, i.e.
  • the areas of reduced pressure at the trailing surfaces of the working vanes are, in a way, filled with the spirally advancing medium balancing the pressure difference significantly.
  • a feature aiding in receiving the flow between the vanes is an advantageous, but not necessary, inclining of the working vanes towards the flow.
  • the working vanes are not necessarily at right angles to the impeller rear plate but inclined against the direction of rotation, i.e. the leading angle between each working vane and the rear plate is less than 90 degrees.
  • Circle 126 may be considered to correspond to the outer circumference of the working vanes of a prior art pump, which, as has been discussed in connection with Figure 1 , do not extend into the cavity of the volute casing at all. In such a case the length of a pressure pulse the working vane creates is considered to be the angular dimension it takes for the working vane to pass the cutwater.
  • the pulse length is intentionally increased for reducing the pulse strength by inclining the working vanes in relation to the direction of the cutwater such that, firstly, a leading edge (normally the front edge, whereby the leading angle of the working vane is sharp) of the working vane passes the cutwater, and, secondly, for a while later, the trailing edge, i.e. the edge attached to the rear plate of the impeller, of the vane passes the cutwater.
  • the pulse length varies between 0 (used in cases when the pulsation is not taken into consideration at all) and about 30 degrees.
  • the pulse length is much longer as the actual cutwater may be considered to be a U-shaped element, i.e. formed of the cutwater 150 of Figure 6 and the edge 126 of the inner wall section of the oval cavity 116.
  • the pulse is considered to start when the outer edge of the working vane 136 starts to descend in relation to the edge 126 of the inner wall section.
  • This is shown in Figure 6 by line L, which meets the circle 142/144 representing the outer circumference of the working vanes 136 at such a point that the leading surface of the working vane 136 meets the point where the extension of the wall (lower one in Figure 6 ) of the outlet duct 152 forms a tangent to the circle 126, i.e. to the edge 126 of the inner wall section of the oval cavity 116.
  • the pulse length is shown in Figure 6 by angle ⁇ , i.e. from the cutwater 150 to line L.
  • the diameter of the pump of the present invention has a smaller diameter than the prior art pump.
  • the diameter of an actual centrifugal pump utilizing the present invention may be reduced by tens of percents. This means in practice that pumps having a higher output may be positioned in the same space with conventional pumps having a lower output.
  • Another measure saving space may be taken by increasing the opening angle of the pressure outlet duct, as the spirally advancing flow remains longer on the wall of the cone (shape of the internal surface of the pressure outlet duct) due to the stronger spiral flow maintaining stable outlet duct flow and a high outlet velocity better.
  • the length of the pressure outlet duct may be shortened (this feature is discussed in more detail in connection with Figure 6 ) whereby the pump occupies a smaller place. All these reductions in the pump dimensions mean, not only savings in space, but also savings in manufacturing costs.
  • the impeller - volute casing configuration of the present invention brings about the following may be mentioned. Firstly, it is evident that the radial forces of the pump are somewhat reduced, which is mainly due to the more uniform spiral flow in the cavity of the volute casing. Secondly, it could be argued that keeping the front edges 140 of the working vanes open in the cavity 116, i.e. without a front plate of a closed impeller the head will be reduced, but the performed tests have shown that the reduction is relatively small.
  • FIG. 5 is a schematical axial cross sectional illustration of a double suction centrifugal pump in accordance with a preferred embodiment of the present invention.
  • the same structural features as discussed in connection with the embodiments of Figures 2 and 4 have been taken into use in a double suction pump.
  • the numbering of the components follows the earlier Figures with the exception that now reference numerals of Figure 1 are preceded by '2'.
  • the outer edges 242 of the working vanes 236 of the impeller 230 extend clearly inside the cavities 216 of the volute casing 210.
  • the option of having no wear plate has been shown.
  • the medium to be pumped advances from the inlets 212 to the cavities 216 along the surface of the volute casing 210, and the front edges of the working vanes 236 follow the inner surface of the volute casing 210 at a small running clearance.
  • Figure 6 is a schematical radial cross sectional illustration of a centrifugal pump in accordance with a preferred embodiment of the present invention.
  • the cross section may be considered to relate to both embodiments discussed above, i.e. to both single suction pumps and double suction pumps.
  • the reference numerals refer to the components introduced in connection with Figures 2 and 4 .
  • Figure 6 also shows the cutwater 150, which is located radially outside of the impeller 130 and divides the medium flow recirculating or actually spirally advancing in the cavity 116 to a partial flow being discharged from the pump via pressure outlet duct 152 and another partial flow that continues to circulate and recirculate in the cavity 116.
  • Figure 6 also shows the working vanes 136 of the impeller 130, the outer edges 142 of the working vanes, or the outer edge 144 of the rear plate 138, when they are located on the same diameter as well as the inner edge 126 of the annular wall 118 of the cavity 116 of the volute casing 110.
  • Figure 6 additionally shows the opening angle ⁇ of the pressure outlet duct 152.
  • the cross section of the pressure outlet duct 152 is, at its left hand end, circular, whereby the overall shape of the outlet duct transforms from the oval cross section of the volute casing to circular shape.
  • the opening angle ⁇ of the pressure outlet duct is in traditional centrifugal pumps in a radial plane at most about 6 degrees.
  • the opening angle ⁇ may be increased to about 9 to 11 degrees without causing flow separation in the diffuser (influencing stability of the pumping).
  • the length of the pressure outlet duct measured from the apex of the outlet duct is one meter when the opening angle is 6 degrees the length required with an opening angle of 11 degrees is only about 55 cm, i.e. the reduction here is 45%.
  • the corresponding reduction is, in practice, in the least tens of percents.
  • FIG. 7 illustrates schematically an axial cross sectional view of a single suction centrifugal pump in accordance with a third preferred embodiment of the present invention.
  • the impeller 330 of the single suction centrifugal pump is a partially closed impeller, i.e. provided with a front plate 350 so that for the majority of their length the working vanes 336 are located between the front plate 350 and the rear plate 338 of the impeller 330.
  • the inner edge 326 of the inner wall section 324 of the annular wall 318 of the cavity 316 of the volute casing 310 is, in fact, an extension of the inner wall section 324 and is located in the front plate 350 of the impeller 330 such that the working vanes 336 extend radially outwardly from the inner edge 326.
  • the front plate 350 which is sometimes called a side plate, is arranged at a distance from the volute such that an annular chamber 352 is left therebetween.
  • the annular chamber 352 is, in an additional preferred embodiment of the present invention, provided with an inlet conduit 354 for introducing chemical to the annular chamber 352.
  • the chemicals that may be added by using the pump of the present invention include, but are not by any means limited to, chlorine dioxide (ClO 2 ), hydrogen peroxide (H 2 O 2 ), sodium hydroxide (NaOH), sulfuric acid H 2 SO 4 , calcium hydroxide (Ca(OH) 2 ), Polyacrylamide (PAM), ferric sulfate (Fe 2 (SO 4 ) 3 ), oxygen O 2 , etc.
  • chlorine dioxide ClO 2
  • hydrogen peroxide H 2 O 2
  • NaOH sodium hydroxide
  • sulfuric acid H 2 SO 4 calcium hydroxide
  • Ca(OH) 2 ) 2 calcium hydroxide
  • PAM Polyacrylamide
  • ferric sulfate Fe 2 (SO 4 ) 3
  • oxygen O 2 etc.
  • the chemical is introduced via the gap 356 into the cavity 316, the chemical enters the spirally recirculating flow to such a location that the flow immediately after receiving the chemical enters the area of the front edges 340 of the working vanes 336 that subject the flow to a strong turbulence, which ensures even and quick mixing of the chemical among the liquid to be pumped.
  • the present invention may be applied in connection with both open, closed, partially closed and semi-open impellers as well as with single or double suction centrifugal pumps.
  • the introduction of chemical/s to the volute discussed in more detail in connection with Figure 7 may be applied in connection with any other embodiment of the invention, and that the partially closed impeller structure discussed in Figure 7 may, naturally, be applied in centrifugal pumps without the chemical introduction, too.
  • a chemical may be introduced in the annular chamber shown in Figure 4 between the wear plate 114 and the volute, and from the annular chamber to the cavity 116 via a gap or grooves similar to that/those discussed in connection with Figure 7 .
  • the chemical introduction into the annular chamber in the volute casing may be performed by means of any conduit leading through the wall of the annular chamber.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP20130190981 2013-10-31 2013-10-31 Pompe centrifuge et procédé de pompage d'une substance Withdrawn EP2868928A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP20130190981 EP2868928A1 (fr) 2013-10-31 2013-10-31 Pompe centrifuge et procédé de pompage d'une substance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20130190981 EP2868928A1 (fr) 2013-10-31 2013-10-31 Pompe centrifuge et procédé de pompage d'une substance

Publications (1)

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EP2868928A1 true EP2868928A1 (fr) 2015-05-06

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105422512A (zh) * 2016-01-12 2016-03-23 中国船舶重工集团公司第七0四研究所 离心泵侧向式螺旋形压出室
US11193504B1 (en) 2020-11-24 2021-12-07 Aquastar Pool Products, Inc. Centrifugal pump having a housing and a volute casing wherein the volute casing has a tear-drop shaped inner wall defined by a circular body region and a converging apex with the inner wall comprising a blocker below at least one perimeter end of one diffuser blade
USD946629S1 (en) 2020-11-24 2022-03-22 Aquastar Pool Products, Inc. Centrifugal pump
WO2022150871A1 (fr) * 2021-01-16 2022-07-21 Weir Slurry Group, Inc. Chemise principale pour une pompe
USD986289S1 (en) 2020-11-24 2023-05-16 Aquastar Pool Products, Inc. Centrifugal pump

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GB338214A (en) * 1929-08-15 1930-11-17 Karl Werner Process for the precipitation of cellulose acetate solutions
US2992617A (en) * 1958-10-23 1961-07-18 Worthington Corp Centrifugal pump with self-priming characteristics
GB1116817A (en) * 1964-07-14 1968-06-12 Egger & Co Impeller pump, for example, a radialflow pump or axialflow pump
JPH07167086A (ja) * 1993-12-13 1995-07-04 Kobe Steel Ltd 固気混合気用の遠心圧縮機
US6171078B1 (en) * 1997-09-04 2001-01-09 Sulzer Electronics Ag Centrifugal pump
CN2809288Y (zh) * 2005-05-26 2006-08-23 石家庄工业水泵有限公司 压滤机给料专用泵
KR200443477Y1 (ko) * 2007-10-08 2009-03-19 주식회사 금호펌프 액체와 가스의 혼합물용 원심펌프
EP2226505A1 (fr) * 2009-03-03 2010-09-08 KSB Aktiengesellschaft Roue vortex dotée de bords coupants
CN202082110U (zh) * 2011-06-07 2011-12-21 张意立 一种外拐角喷水高浓度离心纸浆泵

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB338214A (en) * 1929-08-15 1930-11-17 Karl Werner Process for the precipitation of cellulose acetate solutions
US2992617A (en) * 1958-10-23 1961-07-18 Worthington Corp Centrifugal pump with self-priming characteristics
GB1116817A (en) * 1964-07-14 1968-06-12 Egger & Co Impeller pump, for example, a radialflow pump or axialflow pump
JPH07167086A (ja) * 1993-12-13 1995-07-04 Kobe Steel Ltd 固気混合気用の遠心圧縮機
US6171078B1 (en) * 1997-09-04 2001-01-09 Sulzer Electronics Ag Centrifugal pump
CN2809288Y (zh) * 2005-05-26 2006-08-23 石家庄工业水泵有限公司 压滤机给料专用泵
KR200443477Y1 (ko) * 2007-10-08 2009-03-19 주식회사 금호펌프 액체와 가스의 혼합물용 원심펌프
EP2226505A1 (fr) * 2009-03-03 2010-09-08 KSB Aktiengesellschaft Roue vortex dotée de bords coupants
CN202082110U (zh) * 2011-06-07 2011-12-21 张意立 一种外拐角喷水高浓度离心纸浆泵

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105422512A (zh) * 2016-01-12 2016-03-23 中国船舶重工集团公司第七0四研究所 离心泵侧向式螺旋形压出室
US11193504B1 (en) 2020-11-24 2021-12-07 Aquastar Pool Products, Inc. Centrifugal pump having a housing and a volute casing wherein the volute casing has a tear-drop shaped inner wall defined by a circular body region and a converging apex with the inner wall comprising a blocker below at least one perimeter end of one diffuser blade
USD946629S1 (en) 2020-11-24 2022-03-22 Aquastar Pool Products, Inc. Centrifugal pump
US11408441B1 (en) 2020-11-24 2022-08-09 Aquastar Pool Products, Inc. Centrifugal pump
USD971966S1 (en) 2020-11-24 2022-12-06 Aquastar Pool Products, Inc. Centrifugal pump
USD986289S1 (en) 2020-11-24 2023-05-16 Aquastar Pool Products, Inc. Centrifugal pump
US11668329B1 (en) 2020-11-24 2023-06-06 Aquastar Pool Products, Inc. Centrifugal pump
WO2022150871A1 (fr) * 2021-01-16 2022-07-21 Weir Slurry Group, Inc. Chemise principale pour une pompe

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