GB2177456A - Centrifugal pump - Google Patents

Abstract

The pump comprises an impeller 9 provided with a tooth 18 for engaging a tooth 10 of a rotor 7. The rotor has a projection 8 for centering the rotor in its housing and is partly surrounded by a magnetic core 14. The impeller 9 has a projection 19 which engages a seat 20 in the rotor and is driven by the engagement of the teeth 18, 10. Holes 21 in the impeller allow water to enter the rotor housing to assist centering of the rotor. A volute 3 has an inlet pipe 30 provided with a pin 32 for centering the impeller. <IMAGE>

Description

SPECIFICATION Centrifugal pump This invention relates to a centrifugal pump.

Known type centrifugal pumps usually have a configuration whereby the impeller alone is shown to be placed in a sealed chamber, the rotor and core being housed externally of the same.

Such embodiments involve the use of specific seals and of particular centering means for the impeller, all this involving considerable complexity of assembly and maintenance.

Thus, it is an aim of this invention to eliminate the foregoing drawbacks of known types, by providing a centrifugal pump which has extreme constructional simplicity, leaving out the utilisation of particular seal devices.

Within the above aim it is an object of the invention to provide a centrifugal pump which combines with the preceding feature that of having a considerable simplicity in the centerings.

It is a further object of the invention to provide a centrifugal pump which affords quick and easy maintenance thereof, and, which can be economically manufactured by utilizing ordinary equipment.

According to one aspect of the invention, this aim, and these and other objects which will be apparent hereinafter, are achieved by a centrifugal pump comprising a pump body, removably associable with a volute, characterised in that it has a sealed seat, for a rotor, externally whereof there is removably associable a magnetic core, said rotor being provided with means of centering and engagement with matchingly shaped engagement means rigid with an impeller and removably associable therewith, said impeller being locatable in a preformed seat and having throughgoing holes as well as a seat for a centering means, said volute having a pluralityy of elements for sealed engagement with the pump body, and being orientable with respect to the same.

Further features and advantages of the invention will be apparent from the detailed description of a particular embodiment thereof shown by way of illustration in the accompanying drawing sheets, where: Figure 1 is a perspective view of the pump; Figure 2 is a cut-away exploded view of that same pump; Figure 3 is a bottom plan view of the pump; Figure 4 is a perspective view of the impeller; Figure 5 is a sectional view taken on a longitudinal centre plane; Figures 6 and 7 are sectional views illustrating a further embodiment.

With reference to the foregoing figures, the centrifugal pump 1 is essentially comprised of a pump body 2 and a volute 3.

The pump body 2 has a sealed seat 4 of essentially cylindrical shape having, at the closed lower zone 5, a seat 6 concentrical therewith.

Internally of the seat 4 there is placed a rotor 7 having downwardly a centering means 8 shaped to match the seat 6, at the top end of the rotor, there being present a means of engagement for an impeller9 consisting of a tooth 10 projecting radially therefrom.

The longitudinal axial extension of the seat 4 is slightly greater than the length dimension defined by the rotor 7. Peripherally connected to the free end of the rotor 7 and extending perpendicularly therearound, there being provided a plane 11 having an annular element 12 extending upwardly therefrom; this consists essentially of an elevation presenting a seat for an O-ring 12a, the elevation of the element 12 being in the form of a circular annulus arranged concentrically with the longitudinal axis of the seat 4.

Downwardly of the plane 11 at the exterior of the pump body 2, there are provided one or more longitudinal abutment teeth 13, adapted for locating the position of maximum insertion of the pump body 2 into a magnetic core 14, and leave an air gap therearound.

The centrifugal impeller 9 has one or more radial vanes 15 interconnected at the bottom edges thereof to a plane 16 having a slightly smaller outside diameter than that of the element 12, the impeller 9 also has an essentially cylindrical seat 17 extending along the longitudinal centre axis thereof.

Downwardly of the plane 16 the impeller also has a means of abutment engagement with the tooth 10 of the rotor 7 consisting essentially of a second tooth 18 interacting with the tooth 10; at the seat 17 there projects downwardly a centering element consisting of a cylindrical element 19, correspondingly shaped to match a seat 20 formed at the upper end of the rotor 7.

The tooth 18 is shown to have the form of a segment of a circle having a slightly smaller diameter than that of the seat 4, and is accommodated therein.

The impeller 9 also has, at the plane 16, one or more through holes 21.

Peripherally to the plane 11 of the pump body 2 there are present one or more elements 22 for mounting the volute 3 thereon, the elements 22 may consist of, for example, a plurality of lugs having a threaded hole 23, for co-operation with correspondingly threaded bolts.

The volute 3 is shown to consist of a hollow body 24, of substantially cylindrical shaped, removably associable with the pump body 2, the volute body 24 being provided with an annular base 25 adapted to rest on the plane 11 and having an internal diameter approximately equal to the exterior diameter of the annular element 12.

Perpendicularly to the annular base 25 there are present a plurality of fastening elements 26 consisting of cylinders having an axial bore 27 adapted to axially coincide with the plurality of lugs 23 by rotating the volute 3 relatively to the pump body 2, until the axial bores 27 are in axial alignment with the threaded holes of the lugs 23, thereafter, fixing means such as bolts may be inserted and suitably tightened to effectively unite the pump body 2 and the volute 3.

The volute body 24, associable with the pump body 2, is partly shaped to match the annular element 12, and defines on its interior a chamber 28 for containing the impeller 9, upwardly of said chamber there being formed in the body 24 an opening 29 communicating with a cylindrical suction conduit 30 of the pump.

At the opening 29 there is made rigid with its walls a centering means, not blocking the opening itself, consisting of a cylindrical element having a pin 32 projecting into the chamber 29 and shaped to match the seat 17 formed on the impeller 9, the axis of that pin coinciding, therefore, with that of the seat 4, in the pump body 2.

Laterally on the volute body 24 there is formed a further opening 33 in communication with a cylindrical conduit 34 constituting the pump delivery conduit.

The plane 11 of the pump body 2 may have one or more seats 35 for fastening means and a support.

The operation of the centrifugal pump 1 is the following: initially into the chamber 4 of the body 2 there will be placed the rotor 7, positioning the centering means 8 in the preformed seat 6 and the tooth 10 in the proximity of the plane 11.

Subsequently the impeller 9 will be mounted, taking care to arrange the cylindrical element 19 on the inside of the seat 20 formed on the end of the rotor 7, this allowing for optimum centering of the impeller itself, the holes 21 facilitating the initial passage of fluid inside the seat 4 and allowing therefore self-centering of the rotor in use by forming between it and the walls of the seat 4 a film, e.g. of water; the motion transmission taking place through the interaction of the tooth 10 with the tooth 18.

The following stage of the assembly will consist of superimposing the volute 3 on the body 2, inserting the pin 32 at the seat 17 formed on the impeller 9, that arrangement allowing optimum centering of the elements making up the pump, the rotor and impeller having the same rotation axis.

The seal between the pump body and volute is provided by the peripheral circumferential abutment engagement relationship existing between the exterior lateral surface of the annular element 12 and the interior lateral surface of the annular base 25, with the interposition of the O-ring 12a.

In Figures 6 and 7 there is shown a variation of the centrifugal pump, 101.

Therein the rotor 107 and impeller 109 have a common centering means 136 consisting of a steel pin 137 inserted into the throughgoing seats 117 and 120.

The pin diameterwill be such asto allowfor rotation of the rotor and impeller, its end 138 being inserted and locked in the matchingly shaped seat 139 formed at the lower zone 105 of the rotor 107.

The other end 140 of the pin 137 has an annularly grooved seat 141 for accommodating a matchingly shaped locking element 142 associable with the end itself.

The element 142 is accommodated in a matchingly shaped seat 143 formed at the end of the impeller facing the suction conduit 130 and prevents the same from moving axially in that direction.

Advantageously, the vanes 115 of the impeller have a slightly smaller height dimension than the centre body 144, thereby avoiding any possible interference inside the body 144 itself.

Naturally the materials employed as well as the dimensions may be any ones depending on requirements.

Claims (8)

1.A A centrifugal pump comprising a pump body, removably associable with a volute, characterised in that it has a sealed seat; for a rotor, externally of which there is removably associable a magnetic core, said rotor being provided with means of centering and engaging with matchingly shaped engagement means rigid witter an impeller and removably associable therewith, said impeller being locatable in a preformed seat and having throughgoing holes as well as a seat for a centering means, said volute having a plurality of elements for sealed engagement with the pump body and being orientable with respect to the same.

2. A centrifugal pump as in Claim 1, comprising a pump body which is characterised in that it has a sealed seat of essentially cylindrical shape having a closed first end and an open second end, at the former there being formed a further concentrical seat of a smaller size for a matchingly shaped centering means rigid with the rotor, at the peripheral edge of the latter there being placed a plane having an element formed by an elevation having a substantially circular annular shape arranged to be concentricai with the sealed seat, said element having a seat for sealing means adapted for sealing engagement with the volute, peripherally to said plane there protruding one or more elements for attaching the volute.

3. A centrifugal pump as in Claims 1 and 2, comprising a rotor which is characterised in that it has an outside diameter and a length slightly smaller than the corresponding dimensions of the sealed seat, said rotor having, at its end adjoining the open one of the sealed seat, a centering means, and means of engagement, said centering means being composed of a hollow cylindrical seat with an axis coincident with the centre one of the rotor and matchingly shaped to an element depending from the impeller, said means of engagement being composed of a tooth projecting radially to the centering means as far as at the peripheral edge of the rotor.

4. A centrifugal pump as in Claims 1,2 and 3 comprising an impeller which is characterised in that its wings are interconnected by a plane downwardly of which there protrudes a hooking means and an engagement means rigid with the rotor, said hooking means being composed of a tooth having the shape of an arc of a circle whose outside diameter is shown to be concentrical with and approximately equal to that of the sealed seat formed in the pump body.

5. A centrifugal pump as in Claims 1 and 4 comprising an impeller which is characterised in that it has, at the centre axis, a cylindrical seat for a matchingly shaped centering means consisting of a pin to the lateral surface whereof there are secured one or more small radial bridges of connection to the inner lateral surface of the suction conduit, the plane of said impeller having one or more through holes and a slightly smaller outside diameter than the inside diameter of the elevation protruding from the pump body.

6. A centrifugal pump as in Claims 1,2 and 5 comprising a volute which is characterised in that it consists essentially of a cylindrical body of an intermediate diameter to that of the elevation of the pump body, radiused to an annular base and superimposable on the plane of the pump body itself, through a zone having a step-like discontinuity, upwardly of said base there being rigid a plurality of means of hooking on the pump body consisting of some mutually equidistant cylinders having a through bore superimposable on that of lugs protruding from the pump body.

7. A centrifugal pump as in Claims 1 and 6 comprising a volute consisting of a cylindrical body which is characterised in that it defines, jointly with the plane of the pump body, a seat for the impeller, on the lateral surface of which there being formed an opening communicating with the delivery conduit.

8. A centrifugal pump as in the preceding claims which is characterised by that it has a centering means common to the rotor and impeller, said means consisting of a pin insertable in through seats formed along the longitudinal axis in said rotor and impeller, one end of said pin having an annularly grooved seat for a matchingly shaped element for blocking axial movement of the impeller, the other end being insertable under pressure into a seat formed at the closed end of the pump body, said blocking element being housed in a matchingly shaped seat formed at the end of the impeller facing the suction conduit.