US3545892A

US3545892A - Magnetically-coupled pump

Info

Publication number: US3545892A
Application number: US845639A
Authority: US
Inventors: Frederick N Zimmermann
Original assignee: March Manufacturing Co
Current assignee: March Manufacturing Co
Priority date: 1969-07-07
Filing date: 1969-07-07
Publication date: 1970-12-08
Anticipated expiration: 1987-12-08

Description

Dec. 8, 1970 F. N. ZIMMERMANN 3,545,892

5 MAGNETICALLY-COUPLED PUMP Original Filed March 6, 1968 5Sheets-Sheet 1 :70 75,92 4? J20 EZ.

3 65 III F 5 h 63-15 4.

1N VEN 500 Jaza EAMK M z/Mm E/aMAnN GZMV/I,

Arm/MEX.

Dec. 8, 1970 F. N. ZIMMERMANN MAGNETICALLY-COUPLED PUMP Original Filed March 6, 1968 5 Sheets-Sheet 2 INVENTOR- rREm/mwmmm/m ArMRA/Ey Dec. '8, 1970 F. N. ZIMMERMANN MAGNETICALLY-COUPLED PUMP 5 Sheets-Sheet 5 Original Filed March 6, 1968 INVENTOR FREDERICK N. Zi MMER MANN AIIORNEX.

ec. 8, 19 0 F. N.ZIMMERMANN 3,545,392

MAGNETICALLY-COUPLED PUMP Original Filed March 6, 1968 5 Sheets-Sheet L fig. 15.

Jcz 5 J05 .105 78 .703

Ar RNEI.

Dec. 8,1970 F. N. ZIMMERMANN MAGNETICALLY-COUPLED PUMP Original Filed March 6, 1968 5 Sheets-Sheet 5 1IIVEN 'I'OR. Fae-05m OK A Z/mMH WAA A Fl 5 2 0.

A T 7012 IVE).

United States Patent US. Cl. 417-373 20 Claims ABSTRACT OF THE DISCLOSURE In rotary pumps of the magnetically-coupled type, the pump is formed in separable sections one of which constitutes a body portion and the other a closure portion, there being a protuberant inlet chamber and duct formation projecting from the side of one section, and a protuberant magnet well and surrounding alignment formation on the side of the other section adapted to be circumscribed by a driving magnet rotated thereabout by a motor unit removably conjoined with the pump, there being a rigid non-metallic ring member interposed between the pump and motor units and having annular flange and socket formations cooperative with the pump and motor to align the latter and the driving magnet accurately for very close air-gap clearance about the magnet well, the ring member being non-metallic and having low heat conductivity to serve as a barrier to conductive heat transfer between the pump and motor unit, such heat transfer being further reduced by supporting the driving magnet in a carrier formation which is an integral part of a fan structure proximate to both the motor and pump.

This application is 'a continuation of application Ser. No. 710,958 filed Mar. 6, 1968 now abandoned.

The disclosed improvements relate to magneticallycoupled centrifugal pumps coinjoined with a driving motor contrived as a unitary motor and pump assembly, some of the important features of novelty pertaining to the provision of a pump unit comprising separable body members including a body portion and a cover plate structure therefor, said members being characterized in that a protuberant inlet chamber and duct formation constitute an integral part of one of said members, and a protuberant magnet well and heat-barrier seating means constitute an integral part of the other body member; further features relating to the provision of a non-metallic heat barrier and alignment ring of stable rigid material having good heat insulating and resisting qualities and annular flange or collar formations adapted to interfit with seating formation on the pump unit and a motor head or cage to prevent conductive heat transfer between the units and also to align the motor unit with the magnet Well containing the internal coupling or drive magnet to be maintained between the external driving magnet and the well containing the internal coupling or drive magnet to afford a low magnetic air gap.

Still another feature of the improvements relates to the provision of further means for preventing heat transfer in the form of a ring-like carrier for the external driving magnet which is formed as an integral part of an air impeller or fan rotating in the motor head cage contiguously to the magnet well in the pump unit.

Patented Dec. 8, 1970 p ce The disclosures hereafter set out relate generally to improvements in a type of centrifugal pump of the magnetically-coupled class disclosed in applicants reissue patent No. Re. 26,094 and certain copending applications, namely: Ser. Nos. 584,171; 655,109; 663,161; and 679,777 all in Group 343.

Other features of novelty and utility relate to details of the construction and operation of the embodiments described hereinafter by way of example of preferred forms of construction in view of the annexed drawings in which:

FIG. 1 is a side elevation of a first form of the pump assembly in which the magnet well and heat barrier seat form part of the cover plate and the inlet chamber forms part of the body member;

FIG. 2 is a side elevation of a modified form of the assembly in which the magnet well and seat for the alignment and heat barrier means forms part of the pump body, while the inlet chamber and inlet duct formations are integral parts of the cover plate structure;

FIG. 3 is a side elevation of the magnet-carrying fan structure;

FIG. 4 is a rear elevation of the magnet-carrying fan structure;

FIG. 5 is an exploded assembly view of parts of the assembly of FIG. 1;

FIG. 6 is an elevational view of the motor head cage in the motor unit of FIG. 5;

FIG. 7 is a perspective view of the heat barrier and alignment employed in the embodiment of FIG. 1;

FIG. 8 is a magnified cross-sectional fragment of the heat barrier ring shown in FIG. 7;

FIG. 9 is a side view of the body of the pump unit of FIG. 1 with the cover plate removed to expose the impeller chamber, inlet chamber and impeller spindle;

FIG. 10 is an elevation of the inside face of the integral cover plate and magnet well complementary to the body portion depicted in FIG. 9;

FIG. 11 is an obverse exterior elevational view of the cover plate and magnet well structure shown in FIG. 10;

FIG. 12 is an external elevation of the pump body obverse to the side seen in FIG. 9;

FIG. 13 is an endwise view of the pump unit of FIGS. 9 to 12 shown partly in elevation and partly in section;

FIG. 14 is an endwise view of the modified pump unit depicted in FIG. 2 as seen partly in elevation and partly in section;

FIG. 15 is an exploded assembly view of the modified construction of FIG. 2 showing the pump unit in endwise elevation, the heat barrier and alignment ring partly in elevation and partly in section, the motor cage in elevation, the combination magnet carrier and fan means partly in section and partly in elevation; and a portion of the driving end of the motor in elevation;

FIG. 16 is a side elevation of the modified form of the pump unit shown in FIGS. 2 and 14, and showing the cover plate With integral inlet chamber and duct;

FIG. 17 is an elevational view of the opposite side of the modified pump structure shown in FIG. 16;

FIG. 18 is an elevational view of the cover plate of the modified pump unit exposing the inlet chamber and impeller spindle footed therein;

FIG. 19 is an elevational view of the interior of the pump body of FIG. 17 exposing the impeller chamber and integral magnet well;

FIG. 20 is a magnified fragmentary cross section of the heat barrier and alignment ring employed in the modified assembly;

The form of the apparatus seen in FIG. 1 comprises a pump unit and a motor unit 50 joined as a unitary assembly by means of long through bolts 47 passing through bores in the pump unit to engage in a head structure or cage 49 on the proximate end of the motor, there being interposed between these units a ring-like heat barrier and alignment means 44.

The pump unit comprises a cast body section 21 (FIG. 13), having formed integrally therewith a protuberant inlet chamber 22 from which extends upwardly an inlet duct and threaded pipe nipple formation 23. A discharge duct and threaded nipple 24 extends downwardly from an endwise portion of the body, the relative positioning of these ducts being evident in FIG. 9 which also exposes the interior of the impeller chamber 25 and the subjoined inlet chamber 22 in which is footed an impeller spindle 26, there being an integral boss 27 (FIG. 13) provided centrally of the inlet chamber and having a blind bore into which the end of the spindle is press fitted, said spindle extending outwardly through the impeller chamber and somewhat beyond, as shown in FIG. 13.

Within the pump body is a blade-type impeller 28 (FIG. 13) preferably of molded plastic and having a hub portion 29 through which is extended a bearing sleeve 30 adapted to receive a substantial length of the spindle 26. Joined to the impeller is a cylindrical coupling magnet 31 rotatable therewith and projecting substantially through and beyond the open side of the pump body to be freely housed in a sealing well.

Situated at intervals about the margin of the body casting as in FIG. 9, are radially-salient projections or tabs 33 in each of which are sets of

dual bores

34A, 34B, the former penetrating entirely through the projections to receive motor-mounting through-bolts 47, while the bores 34B are blind and tapped to receive cover plate retaining screws 40, as will appear.

When the impeller and coupling magnet are installed in the pump body, the latter is sealed at its open side 35 by a cover structure comprising a plate portion 36 (FIGS. 11 and 13), from which extends a protuberant magnet well 37 integral therewith and having a wall section as thin as possible consistent with strength with the object of keeping the magnetic air gap as narrow as possible between the internal and external coupling magnets, the outer periphery of the internal driven coupling magnet accordingly being rotated as closely as possible to the inner periphery of the well.

The internal configuration of the cover plate is depicted O in FIG. 10, it being observed also that there are integral tab projections 38 disposed at intervals radially about the periphery of this plate in each of which is a set of

dual holes

38A, 38B matching the like sets of holes and bores in the body casting. An annular prominence or land 39 is formed on the inside face of the cover plate with its circumferential periphery set inwardly of the margins of the plate portion so as to fit closely into the cavity of the pump or impeller chamber, there being a sealing means -G in the preferred form of an O-ring stretched about this land to be pressed against an annular ledge 35L at the open side of the pump body (FIGS. 9 and 13) when the cover plate is secured in assembly therewith, as by means of the fillister-head body or closure screws 40 (FIGS. 1 and 5), each fitted into one of the holes 38B and turned home in the corresponding tapped body bores 34B.

As seen in FIG. 11, the outer face of the cover plate includes an annular moat or recess 41 constituting a ringseating socket surrounding the magnet well (FIG 13 also) and having an inside diameter closely fitting the alignment collar 43 on the appertaining side of a ring-shaped heatbarrier means 44 (FIGS 7 and 8), the latter having on its opposite side another and slightly smaller annular alignment flange or collar 45 (FIG. 8 also) adapted to interfit with a socket formation 57X on the motor head cage, as will appear hereafter. The heat ring 44 is rigid and has a plurality of radially salient ears or tabs 46 each provided with a set of

dual holes

48A, 48B registering with the sets of holes in the

tabs

33 and 38 on the pump body and closure plate, such that when the pump is sealed by application of the closure plate, the heat ring may be pressed into position thereon with its collar 43 snugly engaged in the cover plate recess 41 and the sets of holes in the tabs on the pump body, the closure plate and the ring all registering and the ring fitting flush against the rim of the closure plate by reason of the accommodation of the screw heads 40H in the counter-bores 48B (FIGS. 1, 13).

The electric motor 50 employed in the motor unit may be of conventional construction but it is fitted at its driving and attachment end proximate to the pump with a special head cage 49 (FIGS. 1, 5 and 6) comprising a square base casting 51 adapted to fit against the motor field frame or stack and having tapped bores 52 for bolts 53 attaching the same to said motor stack. Formed integrally with the head casting are large exterior posts 55 separated by intervening grille bars 56 constituting cooling grids, the outer ends of which terminate in integral juncture with a ring member 57, the internal periphery of which constitutes the afore-mentioned receiving socket 57X for the alignment collar 45 on the appertaining side of the heat ring, FIG. 6.

The outermost face of each of the large cage posts 55 has a seating configuration generally matching that of the

salient tabs

33, 46, on the pump and ring components, as well as a set of dual bores, one of which, at 58A, is tapped to receive the long through bolts 47 passing from the far side of the pump body through the tab holes 34A, cover plate holes 38A and heat ring holes 48A. The remaining bore 59 in each cage post is a relief bore for removal of metal to avoid warping stresses due to the substantial disparity in the adjoining metal thicknesses.

Mounted on shaft 60 of the driving motor (FIGS. 3 to 6) is a magnet-carrying fan comprising an integrally formed hub portion 62 from which radiate impeller vanes 63 terminating in integral attachment with magnet supporting means which may take the form of a ring 64 in which the annular driving magnet 65 is secured as by press fit cementing or other means.

The length of the driving magnet in an axial direction is such as to permit it to fully surround the like dimension of the internal driven magnet sealed within the pump well, and a portion 65A (FIG. 5) of the driving magnet assembly and carrier ring projects somewhat beyond the cage casting in order that the magnet may enter the moat or socket recess 41 about said well in circumambient driving relation fully surrounding the inner magnet (FIGS. 1 and 5).

The heat ring 44 is formed of a rigid material having low heat conductivity, capable of standing elevated temperatures, and one which is not subject to any appreciable cold flow and preferably is machineable as well as moldable. Such a material can be had in a mixture of a synthetic plastic material of the class of polysulfone mixed with glass of powder consistency, one suitable type of which is available on the market under the proprietary name of Sulfill. Such a material will readily withstand temperatures as high as 400 F., and has the requisite hardness and stability to take and maintain the accurate flanged configurations disclosed herein to serve the purposes both of blocking conductive heat transfer and maintaining accurate alignment of the motor unit with its driving magnet in optimal close rotative clearance about the driven magnet shield or well, it being understood that the smaller the air gap between the magnets the greater will be the coupling torque.

The heat-ring-alignment means is of particular significance in pump structures employing cylindrical magnets having polar flux action in directions principally radial to the axis of rotation for coaction with the similarly acting flux from a circumambient driving magnet in which arrangements the magnitude of the magnetic air gap requires that the annular driving magnet rotate as closely as possible about the Well containing the driven inner magnet, it being assumed that the wall thickness of the well will be optimally as small as possibly consistent with strength, and that the inner magnet will rotate with its inner periphery as close as possible to the inner surface of the well.

In addition to its utility in aligning the motor unit and its driving magnet with the magnet well, the interposed ring means greatly reduces heat transfer due to conduction between the pump and motor and vice versa, it being understood that such pumps may be used in either hot flow or cold flow lines and in services other than hotwater circulation in heating systems, such as chemical processing, the presently disclosed constructions being particularly useful in applications wherein the temperature in the pump may rise high enough to heat the mo tors appreciably. Conversely, in cold-liquid circulation, it may be required to prevent transfer of heat from the motor into the flow line, and in either of these situations the function of the alignment means 44 as a heat barrier which consistently retains its shape and accuracy of configuration, is of great value.

-In respect to the combination magnet carrier and fan, it is known that heat can adversely affect magnetic action, and the disclosed unitary construction, in addition to effecting economies in manufacture and assembly, serves the purposes of agitating the air in the immediate region of the coupling magnets, as well as the pump body and the motor, while affording a means for uniformly disposing the driving magnet in the most elfective physical and functional proximity to the motor, and the internal magnet shield.

It is of further importance to observe that in the foregoing construction the cover plate is attached to the pump body by screws 40 independently of the attachment of the pump to the motor, in consequence of which it is possible to remove the motor for replacement or servicing without danger of opening up the pump line connections (e.g. 18, 19, FIG. 1), it being impossible to disturb the cover plate without first detaching the motor unit in order to withdraw the heat ring, this embodiment of the device having advantages in these respects similar to those afforded by the variant constructions disclosed in my copending application Serial No. 663,161.

The modified pump and motor assembly shown in FIG. 2 is similar in general aspects to that depicted in FIG. 1 in the respect that it also comprises a pump unit 70 conjoined with a motor unit 100 and an interposed heat barrier and alignment means 75 having flange and socket interfit with both units, there being, however, substantial differences in the pump body in the respect, among others, that the magnet well and surrounding heat-barrier seating formations are formed as integral parts of the pump body and impeller chamber, and not as parts of the cover structure as in the first-described embodiment of FIG. 1.

According to the modified construction illustrated in FIGS. 14, and 17, the magnet well 71 is formed as an integral part of the pump body 70, there being a shallow moat or annular recess 72 formed in said body surrounding the base of the magnet well and bordered by an upstanding collar or circular flange 74 having an outside diameter to fit snugly into the bore or socket portion 76 of a heat barrier ring 75, FIGS. 15, 20, said ring having a cross section different from that of the ring 44 (compare FIGS. 8 and in that it does not have dual salient socketing flanges nor the sets of dual bores as in the Wire peripheral tabs characterizing the ring 44, but instead has smaller peripherally salient tabs 78 in which are single bores 77, there being only one upstanding collar annular flange formation 79 on its outer face adapted to interfit with annular bore or socket in the motor head cage.

Referring to FIGS. 14 and 18, the body of the modified pump has an open side 73 adapted to be sealed off by a closure plate 80 (FIGS. 16 and 19), said plate having as an integral part thereof a protuberant inlet chamber 8] with an externally formed inlet duct and threaded connection nipple 82 communicating sidewise and in an approximately tangential sense (as in the embodiment in FIG. 12 into the low pressure inlet zone surrounding the footed end 84 of the spindle 85, which is fixed in position on the inner wall of said chamber by screw means 86 pasing through a small tight neoprene or like sealing collar 87 seated snugly in a recess 88 in said wall. Nipple 83 connects with the discharge line.

Surrounding the opening to the inlet chamber (FIGS. 14 and 18) is an annular land 89 of lesser diameter than the plate portion 80 and about which is fitted a circumambient gasket or sealing ring G adapted to be pressed against a ledge 90 around the inside of the open side of the body member (FIG. 19) after installation of the impeller, the plate being secured in assembly with the heat ring 75 and motor unit by application of throughbolts 91 in bores 92 (FIGS. 2 and 15) threading into tapped bores 108 in the head cage casting 94 on the motor.

Substantially identical to the construction of FIGS. 3 and 4 of the first-described embodiment, the motor unit of the modified structure includes a magnet-carrying air displacement means or impeller 96 (FIG. 15) having an annular magnet-seating configuration 97 integrally formed with fan blades 97A and hub means 95, the annular driving magnet 98 being secured in a position such that the bore of the magnet annulus can fit entirely and closely for rotation about the active extent of the cylindrical driven magnet sealed within well 71. The magnet-carrying fan means in both embodiments will preferably be cast from a non-magnetic (i.e. zero ferro-magnet inductivity or retentivity) zinc type casting alloy rather than any magnetizable material, for best coupling action.

As viewed in FIG. 15, the motor head cage casting has an annular socket portion 99 into which the annular alignment flange 79 on the heat ring closely fits, whereby, in conjunction with the close fit of the integral collar flange 74 on the pump body into the socket bore 76 of the heat ring, the driving magnet is accurately and permanently disposed in alignment with the magnet well 71 for optimally close rotation thereabout. Preferably, the

head cages

49 and 94 in both embodiments will be cast from a non-ferromagnetic material such as the zinc-alloy preferred for the fan and magnet receiver, because of the close proximity of the latter to the driving magnet.

While both forms of pump unit may be molded from suitable plastic materials, such as polypropylene, the illustrative embodiments preferably have cast bronze bodies and closure plates for the most rugged and durable service in high temperature fluid circulating systems, only the impellers being of plastic in order to prevent corrosion build-up which might interfere with free rotation.

In the pump construction according to FIGS. 9 and 12, the inlet and outlet ducts are formed in the same member and have fixed positions to extend in opposite directions but in approximate parallelism, and are thus suited to in-line pipe and hose connections. Moreover, in this arrangement, the cover plate is independently secured in sealed condition against leakage due to accidental loosening or removal in case of detachment or installation of the motor unit while the pump is connected in the flow 1 line, since it is impossible to gain access to the body tions 90 apart, thereby disposing the threaded pipeor hose-connection nipples in selected positions for other than an in-line arrangement. However, in this embodiment, the attachment of the closure plate is effected by the same bolts 91 serving to join the pump unit, as such, to the motor unit 100, these bolts passing through aligned bores 102 in tabs 103 on the closure plate registering with bores 104 in marginal post formations 105 on the body casting, and passing thence through bores 77 in tabs 78 on the heat ring (FIGS. 2 and 15) to thread into tapped bores 108 in the motor cage, the latter in turn being attached to the motor stack by small screws 110. Thus, the motor itself may be removed by backing out the said small screws 110, which are not particularly accessible, however, leaving the cage attached to the pump; but the entire motor unit, including the head cage, can only be removed by withdrawal of the long through-bolts 91, in which case the cover plate is necessarily loosened and spillage from the fiow line or pump can result.

I claim:

1. In a motor-driven, magnetically-coupled pump and motor assembly, a pump unit including a body member and a closure member therefor; spindle means carried by one of said members and supporting an impeller and a driven cylindrical coupling magnet projecting axially therefrom; one of said members having as an integral part thereof a protuberant cylindrical magnet well into which said driven magnet projects for rotation by an external driving magnet rotated circumambiently thereof, said one member having integral formations arranged concentrically about said well adjoining the juncture of the latter therewith and constituting an annular seating means for a socket interfit alignment member; a motor unit including a motor having a shaft exposed at one end thereof and a head structure affixed thereto at said end in concentricity with said shaft; an annular driving magnet and means carrying the same for rotation concentrically of the axis of said shaft for rotation therewith; means detachably joining said pump unit to said head structure with said driving magnet disposed for rotation concentrically about said well circumambiently of the driven magnet therein; said head structure having integral formations arranged concentrically of the shaft and magnet axis providing a further alignment-member seating means, and a rigid, ring-like alignment member of non-metallic heat-insulative material interposed between said one member of the pump unit and said head structure and having annular portions in close alignment interfit with the respective seating means thereof and fixing the relative axial alignment thereof one with respect to the other such that said driving magnet is accurately positioned in coaxial relation to said well to rotate freely and closely thereabout in an optimal close proximity thereto for the purpose of maintaining a low magnetic air gap between the magnets.

2. A pump and motor assembly according to claim 1 wherein said body member and closure member in assembly define a sealed-off impeller chamber having inlet and outlet ducts communicating therewith, that particular one of said members which does not have as a part thereof the magnet well aforesaid having formed as an integral part thereof an outwardly protuberant inlet chamber into which said inlet duct communicates, said spindle means being secured on an inner wall surface of said inlet chamber to project into and beyond said impeller chamber and into said well concentrically thereof, said impeller cham ber being formed in said particular one of the members.

3. A pump and motor assembly according to claim 1 wherein said body member and closure member in assembly define a sealed impeller chamber having integral inlet and outlet ducts communicating therewith said one member which has the magnet well formed as a part thereof having further formed as an integral part thereof an impeller chamber disposed concentrically of the rotative axis of the driven magnet in said well, said discharge duct being formed as an integral part of said one memher and leading from said impeller chamber; said inlet duct being formed as an integral part of the other said member and terminating in an inlet chamber formed as an integral outwardly disposed protuberance on a wall portion thereof and adapted to confront one axial end of an impeller rotatable in the impeller chamber in concentricity with said axis of the driven magnet; said spindle being fixed at one end on a wall portion of said inlet chamber in axial alignment with said axis and projecting through said impeller chamber and into said well.

4. The construction of claim 1 wherein said integral formations which constitute the seating means of said one member have the form of an annular recess surrounding the end of said well conjunctive with such member, and said recess is bordered by a raised annular flange having close interfit with one of said annular portions of said ring-like member, the latter having on a side thereof proximate to the motor head a further annular configuration in the form of an annular flange having close interfit with the seating means on the head member.

5. A construction according to claim 4 wherein the means joining the pump and motor unit as aforesaid comprise throughbolts passing through portions of the pump body and closure members and said alignment member into engagement with said head structure.

6. A pump assembly according to claim 1 wherein said ring-like member is formed of a hard, thermally stable, non-metallic material having low heat conductivity suffi cient to afford a substantial barrier to conduction of heat between the pump and motor units.

7. A pump assembly according to claim 1 wherein said means carrying the driving magnet comprises a hub member secured on said shaft and having a plurality of radial air-displacing blades formed integrally therewith, said blades having integrally connected thereto an annular magnet socket concentric with the axis of said hub and the motor shaft and having said annular driving magnet secured concentrically therein.

8. A pump assembly according to claim 1 wherein said means carrying the driving magnet comprises an air impeller mounted on said shaft for rotation therewith, said impeller having formed as an integral part thereof a magnet seat in which said driving magnet is disposed in fixed concentricity with the rotative axis of the shaft and air impeller.

9. The construction of claim 8 wherein said air impeller and said magnet seat are disposed for free rotation substantially entirely within said head structure, and the head structure includes heat-exchange grid means relative to which air is displaced by rotation of the air impeller with said driving magnet.

10. The construction of claim 8 wherein said head structure has openings communicating toward the motor and laterally of said axis, and said seat provides a large open bore aligned with the bore of the magnet annulus, and said air impeller has substantial openings in alignment with said bore about the axis of rotation thereof, whereby displaced air can move through the driving magnet and air impeller in either direction toward and from the pump unit and toward and from the motor unit, and displaced air can circulate through the head structure laterally and in a direction into the motor.

11. In magnetically-coupled rotary pumps, a motor unit including a driving motor having a shaft disposed at one end thereof for cooperation with a pump unit; a head structure at said one end including a bore concentric with said shaft; a magnet carrier including a hub portion fixed on said shaft to rotate therewith; air impeller formations integrally formed with said carrier and hub portion; an annular driving magnet supported by said carrier and having a bore coaxially aligned with said shaft; a pump unit and means detachably conjoining the same with said motor unit said pump unit including a pump housing having therein a rotary impeller with a cylindrical coupling magnet disposed to rotate in a protuberant well for concentric driving coaction with said driving magnet when the latter is disposed to rotate about said well; and combination heat-barrier and alignment means interposed between said pump unit and motor unit and comprising a rigid member formed of anon-metallic material having low heat conduction and stable dimension-retaining properties and annular configuration closely interfitting with complementary alignment formations on the pump housing and head structure of a character to align the same one with respect to the other such that said shaft and magnet carrier are disposed in coaxial alignment with the axis of rotation of said driven magnet in the well and the well itself in a mannerilto permit a minimal optimal clearance between the inner periphery of the said bore of the driving magnet and the outer periphery of said well in order to provide and maintain a small magnetic air gap between the driving and driven magnets.

12. In a magnetically-coupled centrifugal pump adapted for aligned attachment to a motor .unit in conjunction with an intermediate alignment means; a pump housing including first and second separably joined body members defining in assembly a pump housing including inlet and discharge ducts; an impeller chamber having an open side and housing a rotary impeller with conjoined driven coupling magnet and spindle means therefor; and an imperforate magnet chamber on a wall of the impeller chamber opposite its open side and saliently protuberant from the housing for cooperation of the driven magnet therein with an external driving magnet rotated by a motor unit; a particular one of said body members having the magnet chamber formed as an integral part thereof 'and having an integral plate-like closure portion adapted to seal off the open side of the impeller chamber and the appertaining magnet chamber in assembly with the other body member as aforesaid; said closure portion of the particular body member having integral annular configurations of recessed character disposed therein circumambiently of the magnet chamber in the region thereof which adjoins the conjunction thereof with said magnet chamber whereby to define annular seating configurations for socket interfit with complementary interfitting alignment configurations on said intermediate alignment means disposed intermediately as aforesaid between the pump housing and a said motor unit; and registering formations on both body members for engagement with means for separably securing said body members in assembled joinder as aforesaid.

13. A pump construction according to claim 12 wherein said particular body member includes as integrally formed parts thereof at least said inlet and outlet ducts and said impeller chamber, and said other body member includes as integral conformations therewith at least the said magnet chamber, plate-like closure portion and said annular seating configurations therein.

:14. A construction according to claim 13 wherein said registering formations comprise radially situated circumferentially spaced tabs about the margins of each said body member adapted for mutual registration in the assembled condition of said body members, and said tabs on the particular body member each include a pair of boltpassing perforations and the corresponding tabs on the other body member each include a through-hole and a tapped'hole respectively registering with one of the perforations in the appertaining tab on the particular body member in assembly as aforesaid, said particular body member being separably joined to the other body member by bolt means engaged in one of the perforations of a tab thereof and a registering tapped hole in an appertaining one of the tabs on said other body member.

15. A pump construction according to claim 12 wherein said particular body member includes as integrally formed parts thereof at least said outlet duct, said magnet chamber and a conjunctive wall portion in which the said annular seating configurations are integrally formed as aforesaid, and said other body member includes as integral parts thereof at least said inlet duct and a platelike closure portion adapted to seal off the open side of the impeller chamber in assembly of the body members as aforesaid.

16. A pump structure according to claim 1 in combination with a motor unit and intermediate alignment means as set forth, wherein said motor unit comprises a motor having shaft means at one end region thereof and an annular driving magnet carried thereby for rotation about said magnet chamber in joinder as aforesaid; said motor further having a head structure provided with annular seating configurations for socket interfit with the said intermediate alignment means; and an intermediate alignment means in the form of a ring-shaped rigid member having annular configurations respectively snugly engageable in socket interfit with the annular seating configurations on a body member of the pump housing as aforesaid, and the annular seating configurations on said head structure; and means engaging said body members, said intermediate alignment means and said head structure for joining the same in assembly as aforesaid.

17. A magnetically-coupled centrifugal pump including, in combination, a housing defined by separable first and second body members providing in assembly an impeller chamber, a protuberant magnet Well communicating with said chamber and disposed outwardly of the housing for cooperation with a circumambient annular driving magnet; spindle means extending into said chamber and well to support a rotary impeller and attached driven magnet, said magnet disposed in said wall; said impeller chamber having an open side; formations integral with at least one of said body members defining inlet and outlet ducts communication into and from said chamber; a motor unit joined with said housing in axial alignment with said well and the driven impeller magnet therein; said motor unit having a head structure and shaft means projecting from an end portion thereof proximate to said well and said shaft means carrying an annular driving magnet disposed to rotate about said well and said driven magnet therein; and an intermediate aligning ring interposed between a wall portion of a particular one of said body members integrally conjoined with said well and serving in assembly as aforesaid as a closure for said open side of the impeller chamber; said wall portion having formed as an integral configuration thereof annular seating means including a shallow moat extending about the region of said well which is integrally conjunctive with said wall portion; said aligning ring having an annular seating configuration closely interfitting with said seating means and having further annular seating configurations closely in terfitting with complementary annular seating formations on said structure, whereby the motor unit and said driving magnet are accurately aligned axially with said magnet well and the driven magnet therein to enable very close rotation clearance with small air gap between the inner periphery of the driving magnet and the outer periphery of said magnet well; and means removably securing said body members and intermediate member in assembly with the head structure of said motor unit, as aforesaid. I

18. The combination of claim 17 wherein said intermediate member is formed of a non-metallic material having low heat conductivity to serve additionally as a heat barrier between the pump housing and motor unit.

19. The combination of claim 17 wherein said intermediate member is formed of a non-metallic, heatresistive and poorly heat-conductive material to impede conductive transfer of heat between the pump and motor unit, and said annular seating configurations of the intermediate member comprise annular flange formations on opposite sides thereof respectively engaging in socket interfit with said seating means about the well on one side thereof, and with said annular engaging configurations on the head structure on the other side thereof.

20. The combination of claim 17 wherein said annular seating means includes in addition to said shallow moat, an annular collar upstanding about the rim of said moat, and said annular seating configurations on the aligning ring comprise an annular socket exposed on at least one side thereof for tight socket interfit with said collar, and said ring has on the opposite side thereof an outstanding annular collar adapted for tight socket interfit with the said annular seating formations on the head structure.

References Cited UNITED STATES PATENTS 2,941,477 6/1960 Dalton 103-87 2,975,713 3/1961 Wright 103-87 3,195,467 7/1965 Collet 103--87 3,354,833 1'1/1967 Laing 103-87 ROBERT M. WALKER, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF commoner:

Patent No 3', 5145, 892 Dated December 8, 1970 Frederick N, Zimmarmarm It is certified that error appears in the aboveidentified patent and that said. Letters Patent are hereby corrected as shown below:

Column 1, line 56, should read: --well on the pump so that minimal rotational clearance oan--; column 1, line 58, change "drive to --driven--; column 2, line 29 after "alignment", insert --ring--; column 5, line 70, change "wire" to --wide--; column 5, line 73, before "annular", insert ----or--; column 6, line 8, the parenthetical portion should be closed after "Fig, 12"

Signed and sealed this 6th day of June l9 (SEAL) Attest:

EDWARD I l-FLETCHER, JR, ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents