Axial flow pump having a non-circular outlet cross-section

Abstract

The invention relates to a hydraulic pump (10) comprising a pump shaft (52) and a casing (46) delimiting a liquid circulation duct (44) in which the cross-section of the outlet orifice (12) is flattened and is oriented such that the liquid outlet direction (14) is inclined from a longitudinal axis (22) of the pump shaft passing through the casing, the casing comprising a first segment (100a) in which the inside surface (102a) has a circular cross-section centred on said longitudinal axis (22) and surrounding a pump impeller (60) supported on the pump shaft (52). According to the invention, the first segment (100a) has a downstream end starting from which the cross-section of the casing inside surface becomes flattened.

Claims

1. Hydraulic pump comprising a pump shaft and a casing delimiting a liquid circulation duct in which the cross-section of the outlet orifice is flattened and that is oriented such that the liquid outlet direction is inclined from a longitudinal axis of the pump shaft passing through said casing, the casing comprising a first segment in which the inside surface has a circular cross-section centred on said longitudinal axis and surrounding a pump impeller supported on the pump shaft, wherein said first segment has a downstream end from which the cross-section of the casing inside surface becomes flattened, and wherein said flattened cross-section of the outlet orifice is generally rectangular in shape, wherein the casing comprises a second segment formed in continuity with the first segment, the second segment having an inside surface with a variable cross-section and being arranged entirely around the pump shaft, and being centred on the longitudinal axis over its entire length, said casing comprising an elbow formed in continuity with the second segment, and an outlet segment formed in continuity with the elbow, the pump shaft crossing said casing at the elbow, said elbow and the outlet segment having an internal surface with the same cross-section, this cross-section being identical to the cross-section of the outlet orifice located at the downstream end of said outlet segment.

2. The pump according to claim 1, wherein the cross-section of the inside surface of the downstream end of the second segment is identical to the cross-section of the inside surface of the outlet orifice of the pump.

3. The pump according to claim 1, further comprising a pump shaft support system installed inside said circulation duct, the system comprising a support structure fixed to the casing and a rotational guide bearing of the pump shaft supported by the support structure, wherein the pump further comprises an opening in the casing from which a conduit for passage of the pump shaft extends inside said circulation duct as far as the shaft support system, and in that the pump shaft extends freely through said conduit.

4. An aquatic activity zone designed to generate a water current using at least one pump according to claim 1.

5. The aquatic activity zone according to claim 4, further comprising: a slide surface that defines a slope; and a water reservoir, wherein the at least one pump is fed from said water reservoir and oriented so as to spray water on said surface.

6. The pump according to claim 1, wherein the circular cross-section lies on an imaginary plane that is perpendicular to said longitudinal axis.

7. The pump according to claim 1, wherein the elbow is formed downstream from the first segment.

8. The pump according to claim 7, wherein a cross-section of the inside surface upstream of the elbow is identical to the cross-section of the inside surface of the outlet orifice of the pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This description will be made with reference to the appended drawings among which;

(2) FIG. 1 shows a diagrammatic side view of an aquatic activity zone according to a preferred embodiment of this invention;

(3) FIG. 2 shows a top view of the aquatic activity zone in FIG. 1;

(4) FIG. 3 shows a perspective view of one of the pumps installed in an aquatic activity zone shown in the previous figures;

(5) FIG. 4 also shows a perspective view of one of the pumps with some covers removed to improve visibility of the pump components;

(6) FIG. 5 is a diagrammatic view showing immersion of one of the pumps in the aquatic activity zone;

(7) FIG. 6 is a sectional view taken along line VI-VI in FIG. 5;

(8) FIG. 7 shows a perspective view of the pump shown in FIGS. 3 to 6, partially cut in a plane of symmetry of the liquid circulation duct;

(9) FIG. 8 shows a sectional view of a part of the pump shown in FIG. 7, this view being taken on line VIII-VIII in FIG. 9;

(10) FIG. 9 is a sectional view taken along line IX-IX in FIG. 8;

(11) Ia FIG. 10 is a view similar to the view in FIG. 7, on which the different segments of the liquid circulation duct have been identified;

(12) Ia FIG. 11 is a front view of the pump shown in FIG. 10;

(13) FIG. 12a is a sectional view taken along one of the lines A-A and A-A in FIG. 10;

(14) FIG. 12b is a sectional view taken along line B-B in FIG. 10; and

(15) FIG. 12c is a sectional view taken along any one of the lines C-C, C-C and C-C in FIG. 10.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

(16) Firstly with reference to FIGS. 1 and 2, the figures show an aquatic activity zone 1 according to a preferred embodiment of the invention. In this case, artificial conditions for practicing a sports or leisure activity such as <<surf>>, <<bodyboard>> or <<wakeboard>>, or any other similar activity in the domain of slides, will be created in the zone 1.

(17) Firstly, the activity zone comprises a water reservoir 2 that in this case is retained in an artificial pool 4. In the embodiment shown, it is a wholly artificial zone 1 that can be disassembled and reassembled on site, including the pool 4. It should be noted that alternatively, the artificial pool 4 could be a fixed non-transportable artificial pool, without going outside the scope of the invention.

(18) The zone 1 also comprises a slide surface 6, positioned above the pool 4. Alternatively, this slide surface 6 may be arranged at least partly within the pool 4, preferably in the upstream part of this pool 4.

(19) The surface 6 defines a possibly progressive slope. This slope is preferably formed by an inflatable structure taking up the required slope, and on which a fabric is stretched to create a smooth surface on which water can easily flow. Preferably, the fabric is fixed to the inflatable structure and designed such that it becomes tensioned as the structure is inflated.

(20) Moreover, the zone 1 comprises a plurality of pumps specific to this invention, these pumps 10 being arranged side by side along the direction transverse to the slope 6. Each pump has one part immersed in the water container 2 and is arranged facing a low point of the slide surface 6. Moreover, as can be seen in FIG. 1, the pump has an outlet orifice 12 oriented such that the liquid escapes along a liquid outlet axis 14 parallel to the low end of the slide surface 6.

(21) Therefore during operation, each hydraulic pump 10 sprays a laminar jet 10 on the slide surface 6, water flowing from the bottom to the top of the slope until reaching an end downstream from the slope at which there is a water reception well 16 from which water is rerouted back into the pool 4. Consequently, the water circuit in the activity zone 1 is a closed circuit.

(22) Moreover, the activity zone 1 comprises a multitude of safety elements 20 surrounding the slide surface 6 so that a person sliding on it cannot accidentally fall off it. Such safety elements 20 are preferably inflatable shock absorbing elements, or similar elements made of foam. Similar elements may be provided in front of the part of each pump 10 above the water surface, so that the person sliding on the surface 6 cannot accidently strike this pump part.

(23) The layout of the different pumps can be adapted to the needs encountered, particularly concerning spacing, inclination, depth in the pool, or the jet orientation to create parallel and/or divergent and/or convergent jets. These parameters can be fixed at the time of assembly, or they can be changed during operation.

(24) The outlet orifice 14 has a flattened cross-section capable of discharging a stretched water jet. A flattened section preferably refers to a generally rectangular or elliptical shaped section with major axis parallel to the generating line of the slide surface 6. Therefore this outlet orifice is oriented along the axis 14 that is inclined relative to the longitudinal axis 22 of a pump shaft (not marked in FIG. 1), this pump shaft preferably being vertical. Preferably, the inclination between axes 14 and 22 is of the order of 90, but more generally may be between 60 and 120, although other values could be adopted without going outside the scope of the invention, depending on needs encountered.

(25) With reference to FIGS. 3 to 6, the figures show specific means by which each pump 10 can be placed in the pool 4, in the position shown in FIG. 1. Firstly, note that the pump is provided with gripping means 26 in the form of a handle that can be retracted into the pump when the pump is not being moved. The pump is also fitted with wheels 28 at the front and the back of this pump along the direction of the axis 22, at the bottom of the pump. Consequently, the pump can be moved along a horizontal surface 30 leading to the pool 4, running on this surface 30 by pushing or pulling on the gripping handle 26. The pump can thus be displaced by rolling with its axis 22 parallel to the support surface 30, as far as an end of the pool 4 where pump support means 32 are provided fixed to the surface 30. These means comprise two clevises 34 each supporting a guide roller 36 that fits into complementary rails 38 provided on the bottom of the pump. Consequently, when one of the front wheels penetrates between two clevises as shown on the view on the left of FIG. 5, the pump can be centred so as to make the rollers 36 correspond with the rails 38. Therefore these elements 36, 38 may engage before the pump is pivoted to be inclined at 90, to obtain the final position in which the longitudinal axis of the pump shaft 22 is parallel to the vertical direction. This tipping operation is done while lowing the pump into the pool 4, by displacement of rollers 36 along the rails 38. This operation can be done comfortably by an operator standing up in zone 30, while manipulating the assembly using the gripping handle 26. Lowering the pump 10 is stopped when each roller 36 reaches the bottom of its corresponding rail 38, in the position shown in FIG. 1. In this position, the front wheels bear in contact with the vertical wall of the pool 4, while the weight of the pump is resisted essentially by engagement between the rollers and the rails.

(26) With reference more specifically to FIGS. 7 to 9, the figures show a part of any one of the pumps 10, each of which preferably has the same design. Note that each pump will output a high flow, for example of the order of 100 to 600 m.sup.3/h.

(27) The pump 10 is fitted with a platform 40 supporting a motor 42 below which there is a circulation duct 44 delimited by a casing 46. The part that will be above the water is the part containing the motor 42 located above the platform 40, while the part that will be immersed comprising the liquid circulation duct 44 is located under this platform 40. Not also that the pump will be covered with protective covers, both on the immersed part and on the part above the water, although they are not shown entirely. For example, the cover 48 shown in FIG. 7 surrounds the circulation duct 44 and its casing 46 that delimits it.

(28) The outlet orifice 12 with its flattened cross-section is located at the downstream end of the circulation duct 44 in the general shape of in inverted <<L>>. The upstream end of this duct communicates with a tapered water intake 50. Therefore the shape of this intake 50 is tapered to become larger in the outwards direction, as far as a lower cover 48 through which water penetrates into this intake.

(29) The pump 10 comprises a pump shaft 52 that is therefore oriented along the longitudinal axis 22 on which it is centred. This shaft comprises a top end called the connection end that is coupled in rotation to a rotating part 54 of the motor 42 and more precisely is coupled to an output shaft 56 from this rotating part, also called the drive shaft. The coupling is made through appropriate mechanical means 58 that are for example in the form of an Oldham joint or a universal joint. These mechanical coupling means 58 are preferably located under the platform 40. Moreover, the pump shaft 52 and the drive shaft 56 are coaxial, although a small misalignment between these two shafts can be tolerated due to the nature of the mechanical coupling means 58, and also due to the design selected for the passage of the shaft through the casing 46, as will be described below.

(30) Moreover, the pump shaft 52 has a bottom end on which a pump impeller 60 in the form of a simple screw is fitted. This screw is located in the upstream part of the liquid circulation duct, close to the intake 50.

(31) The shaft 52 is guided in rotation by a support system 64 comprising a support structure 66 fixed onto the casing 46. This support structure 66 comprises a shell 68 that will be placed in contact with or close to the inside surface of the casing 46, and radial arms 70 extend inwards from this shell as far as a reaming 72 with its centre on the axis 22. Moreover, the support system 66 comprises a rotational guide bearing 74 housed in the reaming 72 that supports it. This bearing 74 has an outside surface with circumferential grooves in which friction seals and seals 76 are preferably arranged, in contact with the reaming 72. The bearing 74 is located close to the bottom end of the shaft 52 supporting the screw 60. It guides this pump shaft 52 in rotation due to an inside surface with which this shaft is in contact. Preferably, it is a bearing through which a flow of cooling water and/or lubrication water can pass, in the form of a water-lubricated bearing, or water lubricated liner, or a <<hydrolube>> ring. As can be seen in FIG. 9, the hydrolube ring 74 has an inside surface with very small axial grooves 80 through which water can circulate along the shaft 52. The top end of the hydrolube ring 74 is contacted in a sealed manner, preferably through an O-ring 82, through a shaft passage conduit 84 in the form of a tube with a circular cross-section centred on the axis 22.

(32) This tube 84 extends like a well into the circulation duct 44, starting from the casing opening 87 close to the mechanical connection means 58. Therefore the tube 84 extends vertically along axis 22 from the opening 87 to which it is connected in a leak tight manner, as far as the hydrolube ring 74 to which it is also connected in a leak tight manner. One of the special features is that the shaft 52 passes freely through the tube 84, a radial clearance being provided so that the pump shaft 52 can move and/or bend inside this tube, to be able to handle a misalignment problem between this pump shaft 52 and the drive shaft 56. The selected radial clearance and the length of the free shaft in the tube 84 from the support system 64 are such that they are capable of absorbing significant misalignments, for example of the order of one or several millimetres.

(33) Also, the shaft 52 is guided in rotation between its connection end and its opposite end on which the screw 60 is fitted only by the hydrolube ring 74. The annular space 86 between the shaft 52 and the tube 84 is preferably left entirely free, allowing the evacuation of a very small flow of cooling and/or lubrication water introduced from the grooves 80 in the hydrolube ring 74. This flow is obviously negligible compared with the pump flow outlet through the outlet orifice 12. This flow is preferably evacuated by gravity through the top end of the tube surrounded by the casing opening 87 in a sealed manner.

(34) Since the connection between the bottom end of the tube and the hydrolube ring 74 is leak tight, the entire flow circulating in the annular space 86 is derived from the passage of liquid through the calibrated grooves 80 in the hydrolube ring.

(35) In this configuration, it should be noted that the pump shaft 52 is not held in place along the axial direction by the system 64, such that the pump shaft can be easily inserted/extracted during fabrication and maintenance operations. Similarly, when the motor is separated from the platform 40 and the screw 60 is pulled out from the bottom end of the pump shaft 52, the assembly composed of the motor 42 and the shaft 52 can easily be extracted/inserted axially without any other assembly/disassembly operations, simply by sliding the shaft 52 through the internal surface of the hydrolube ring 74.

(36) The hydrolube ring 74 is preferably the only wear part in the pump, and can be replaced from the intake 50 very easily, simply by removing the screw 60 to obtain access to it.

(37) As can be seen more clearly in FIG. 7, the casing 46 is preferably made of two parts, each of the two parts preferably being made from a single piece. These two parts are preferably symmetric about a median vertical plane of the circulation duct 44. Thus, by providing two half-parts like two half-shells, each with a half-cavity to form the casing opening 87, it is thus possible to insert the top end of the tube 84 between these two half-shells. If necessary, a seal can be made by using one or several seals between the opening 87 and the top end of the tube 84.

(38) Note also that the opening 87 is provided with a shoulder 89 to enable axial thrust on the tube 84, to push the tube into contact with the hydrolube ring 74. Preferably, each half-shell that defines part of the duct 44 over its entire length, is made from a non-metallic material, for example plastic or a composite material. The same applies for the shaft passage tube 84 that could alternatively be incorporated in these half-shells.

(39) It should also be noted that for the attachment of the structure 66 on the casing 46, the shell 68 is provided with radial projections 89 that fit into recesses 91 formed on the inside surface of the casing. This cooperation between the projections 89 that resemble plates and the recesses 91 prevents rotation and translation movements along the axis 22 between the casing 46 and the structure 66. This also enables precise angular indexing of the support structure 66 relative to this casing 46.

(40) It is also shown that the hydrolube ring 74 is preferably made of brass, bronze or stainless steel.

(41) As can be seen better in FIGS. 4 and 7, the casing has its two half-shells 46a, 46b that are assembled to each other by bolts 93 connecting casing flanges 95 provided on these two half-shells.

(42) FIGS. 10 to 12c show details of the design of the liquid circulation duct 44. Firstly, near the bottom part, the circulation duct is defined by a first casing segment 100a with a constant circular cross-section, centred on the axis 22. This segment surrounds the screw 60 supported by the pump shaft 52. A second segment 100b is provided starting from the downstream end of this first segment 100a, also centred on the axis 22. This second segment 100b is in downstream continuity with the first segment 100a, and is specific in that it has an inside surface with a variable cross-section, becoming flatter towards the outlet end. FIG. 12a shows the shape of the cross-section of the internal surface 102a of the first segment, therefore this circular shape is invariable between the centre of the segment 100a and its downstream end. FIG. 12b shows the inside surface 102b at the centre of the second segment 100b, this cross-section having a flattened shape in which the large dimension is larger than the diameter of the section shown in FIG. 12a, and in which the small dimension along the direction of the height is less than this diameter. Thus, the cross-section of the inside surface 102b of this casing portion changes progressively along the entire length of this second segment 100b from a circular shape to a flattened rectangular shape as shown in FIG. 12c, corresponding to the downstream end of this second segment.

(43) There is a 90 elbow 100c located in downstream continuity with the second segment 100b, the cross-section of this elbow remaining unchanged, with the shape shown in FIG. 12c. Similarly, an outlet segment 100d is located in downstream axial continuity of the elbow 100c, and also has an internal surface with a cross-section identical to that of the elbow and the downstream end of the second segment. This cross-section is then identical to the cross-section of the outlet orifice 12 located downstream from its outlet segment 100d. Therefore it should be understood that the inside surfaces 102c and 102d of the elbow 100c and of the outlet segment 100d have a constant cross-section with the same shape as that shown in FIG. 12c. Obviously, the only exception to this constant shape cross-section is at the part of the elbow containing the opening 87, although the general rectangular shape remains unchanged in elbow sections passing through this opening 87.

(44) Consequently, in starting and completing the flattening of the cross-section of the circulation duct before the elbow through which the pump shaft 52 passes, the dimensions of the pump 10 along the direction of the axis 14 can be reduced, while producing a high performance laminar jet at the discharge from the outlet orifice 12.

(45) Note also that, as an example for guidance only, the area of the circular cross-section in FIG. 12a is practically the same as the area of the outlet rectangular cross-section in FIG. 12c, the ratio between these areas being between 0.9 and 1.1. The variation of the ratio between the areas of the cross-sections preferably lies within this interval of values along the entire length of the circulation duct.

(46) Obviously, those skilled in the art can make various modifications to the invention as described above only as non-limitative examples.