Abstract:
An immersion motor includes a housing ( 3 ) having a wall ( 4 ) with a watertight cable penetration ( 5, 6; 5, 6 ′). The cable penetration includes an inlet ( 5 ) in the wall ( 4 ) for a cable ( 25 ) and a sealing collar ( 6; 6 ′) that can be released from the inlet ( 5 ) having a penetration ( 20 ) for the cable ( 25 ). The sealing collar ( 6; 6 ′) includes a first seal ( 45; 45 ′) disposed on the penetration ( 20 ) and means for applying force ( 75, 85, 90 ) to the first seal ( 45; 45 ′), which is designed for permanently applying force to the first seal ( 45; 45 ′) radially in the penetration ( 20 ). The cable penetration ( 5, 6; 5, 6 ′) further includes means for releasably attaching ( 35, 40 ) the sealing collar ( 6; 6 ′) to the inlet ( 5 ). At least one second seal ( 120, 125 ) is provided between the sealing collar ( 6; 6 ′) and the inlet ( 5 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Section 371 of International Application No. PCT/EP2009/005868, filed Aug. 13, 2009, which was published in the German language on May 14, 2010, under International Publication No. WO 2010/051870 A1 and the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to an immersion motor as well as a submersible pump with such an immersion motor. 
     Immersion or submersible motors are usually completely immersed in liquid, for example water, during their operation. Such a submersible motor is a typical constituent of a submersible pump or submersible pump unit, and lies together with the submersible pump within a shared submersible pump housing. Submersible motors are here routinely supplied with electrical energy via electric feed lines. For purposes of electrical supply, it is necessary that the cables are introduced into the submersible motor housing or submersible pump housing in a watertight manner. 
     For example, a watertight cable feed-through for supplying power to a submersible motor is known from DE 42 13 306 C1. However, impurities, e.g., particles or dirt, can easily get into the seal in submersible motors with such cable feed-throughs, in particular when dismantling the cable from the submersible motor housing. Over time, this can result in a limited sealing affect or even complete loss of sealing action by the cable feed-throughs, so that the proper function of the submersible motor is no longer guaranteed. 
     BRIEF SUMMARY OF THE INVENTION 
     Therefore, an objective of a preferred embodiment of the present invention is to create an immersion or submersible motor improved in this regard, and a submersible pump with such a submersible motor. 
     The above objective is achieved by a submersible motor or a submersible pump with a submersible motor having a housing, which includes a wall with a watertight cable feed-through, which includes an inlet in the wall for a cable and a sealing collar that has a feed-through for the cable and can be detached from the inlet. Advantageous preferred embodiments of the present invention are indicated in the following specification and the drawing. 
     The submersible motor according to a preferred embodiment of the present invention includes a housing, which has a wall with a watertight cable feed-through. The cable feed-through includes an inlet in the wall for a cable and a sealing collar that can be detached from the inlet with a feed-through for the cable. The sealing collar has a first seal located on the feed-through, and a means for applying force to the first seal. The latter is here designed for permanently applying force to the first seal radially in the feed-through. In addition, the cable feed-through has means for detachably securing the sealing collar to the inlet, wherein at least a second seal is provided between the sealing collar and inlet. 
     In the submersible motor according to a preferred embodiment of the present invention, the cable can be introduced into the housing of the submersible motor by guiding the cable through the feed-through of the sealing collar on the one hand. The permanent radial application of force to the seal into the feed-through permanently holds the seal tightly against the cable. This establishes a permanent seal between the cable and sealing collar. The sealing collar is further tightly and detachably connected with the wall of the housing, in that the second seal enables a sealing abutment between the sealing collar and inlet. The housing-side opening for the sealing collar feed-through and the outside opening of the inlet in the wall here overlap, so that the cable gets inside the submersible motor. As a result, the cable feed-through is made watertight by having the cable with the first seal situated watertight in the sealing collar, and by having the sealing collar with the second seal situated watertight at the inlet of the housing wall. The cable can here be detached from the submersible motor housing wall by detaching the sealing collar from the wall inlet. Conversely, the cable can be mounted to the wall by mounting the sealing collar in the inlet in the wall. 
     On the one hand, within the meaning of a preferred embodiment of the present invention, the application of a permanent force to the first seal radially in the feed-through is to be understood as the type of force application that brings about a sealing abutment between the first seal and cable, even after a long period of time and possibly accompanied by a decreased elasticity of the first seal, for example via plastic deformation or embrittlement. This takes place by way of a permanent outer application of force to the first seal, as described below. As a result, the cable feed-through remains permanently watertight, so that a submersible motor according to the invention has to be serviced less often. 
     On the other hand, the application of a permanent force to the first seal radially in the feed-through can also be understood as the type of force application that persists even when the cable is detached from the housing wall. The first seal is here preferably provided for the permanent, tight abutment on the cable and on an inner periphery of the feed-through, independently of the attachment of the sealing collar to the housing. This makes it possible to detach the sealing collar from the inlet in the housing wall, while the cable remains situated watertight in the feed-through of the sealing collar. This prevents particles or dirt from getting between the first seal and the cable given a dismantled sealing collar, and contaminating or damaging the first seal in the process. As a result, a continued reliable seal is ensured even when the cable is again assembled. 
     The first seal is preferably fabricated out of a soft and elastic material. Such a material can be suitably adjusted to a section of the outer peripheral surface of the cable. In this way, irregularities on the cable casing or deviations from the exact stipulated tolerances do not affect the sealing effect of the first seal. The soft and elastic material preferably involves rubber or an elastomer. In addition, the seal is preferably a sealing ring, which circumferentially surrounds the longitudinal axis of the feed-through for the cable. 
     In a preferred embodiment of the present invention, the first seal in the submersible motor is circumferentially surrounded by a sealing collar housing. It is especially preferred that the sealing collar housing is designed as a casing for the first seal along an axial section of the sealing collar, for example in the form of a sleeve. It is further preferred that the sealing collar housing forms at least part of the feed-through. The first seal is preferably annular, and its inner periphery tightly abuts the cable, while its outer periphery tightly abuts the interior wall of the sealing collar housing. This makes it possible to pre-stress the seal in a radial direction. 
     The means for applying force to the first seal in the submersible motor preferably comprises two clamping surfaces, between which the first seal lies, and by means of which the first seal has a force applied axially to it in such a way as to press the seal radially into the feed-through and against the cable. It is especially preferred that the first seal here consists of a soft and elastic material as described above, which abuts an inner periphery of the feed-through or sealing collar housing. The axial application of force to the first seal via clamping surfaces now causes the material of the first seal to be axially clinched and to radially yield. Since the first seal abuts the inner periphery of the feed-through, the material of the first seal penetrates radially inward, into the feed-through, and is pressed against a cable situated there. 
     In a further development of a preferred embodiment of the present invention, a permanent force is applied to the first seal into the feed-through with a means for applying force to the first seal that comprises at least one compression spring element acting in the axial direction. This compression spring element applies force to at least one of the clamping surfaces. The compression spring element is here preferably axially clinched relative to its rest position, and hence pre-stressed. In this way, the compression spring element abuts the first seal under a stress, even given an altered axial length of the latter. Therefore, even if the first seal loses elasticity over time, and for example is exposed to plastic deformation, a sufficiently high force continues to be applied by way of the compression spring element. As a result, an abutment force to the sealing surface can be ensured between the cable and seal independently of the internal stress of the seal. 
     The compression spring element is usefully a disk spring or disk spring packet. Disk springs advantageously have high spring constants, and therefore generate a high level of force acting on the first seal, and consequently a high sealing action. In a preferred embodiment of the present invention, the compression spring element is oriented in such a way as to act in the direction of the longitudinal axis of the feed-through. The compression spring element includes a central opening that is coaxially oriented with the feed-through, so that it circumferentially surrounds the feed-through of the sealing collar. It is further preferred that the compression spring element pushes off a front wall detachably arranged on the sealing collar. Detaching this front wall from the sealing collar housing here enables a complete relaxation of the compression spring element. For example, the application of force to the first seal can be suspended as a result. A cable can be introduced into the feed-through of the sealing collar, or replaced as needed, for example. 
     In an advantageous further development of a preferred embodiment of the present invention, the means for attaching the sealing collar in the submersible motor include an abutment surface on the wall that is angled relative to the longitudinal axis of the feed-through of the sealing collar, and situated on the sealing collar. This abutment surface allows the sealing collar to easily abut the wall of the submersible motor housing. It is especially preferred that the abutment surface extends perpendicular to the longitudinal axis of the feed-through. For purposes of attachment to the wall, it is usefully that the abutment surface comprise screw holes for bolting the abutment surface with the wall. 
     In an advantageous preferred embodiment of the present invention, the submersible motor is provided with a third seal to establish a tight abutment on the outer periphery of the cable and an inner periphery of the sealing collar housing. The third seal here preferably also abuts an inner periphery of the feed-through of the sealing collar housing. This ensures a larger abutment surface on the cable, and hence an enhanced retention force between the cable and seals in an axial direction. As a result, the third seal acts in particular as strain relief for the cable. In this way, forces acting on the cable caused by tensile stress outside the housing of the submersible motor are conveyed from the seals to the sealing collar housing. By contrast, the cable end lying within the submersible motor housing, and in particular electrical contacts lying at the cable end, are not exposed to tensile stress. In particular, the third seal can be situated on the outside of the housing of the first seal, so that the third seal simultaneously acts as a strain relief for a section of the cable lying on the first seal, and its sealing action is not diminished by exposure to tensile forces. 
     In another preferred further development of the present invention, the sealing collar in the submersible motor has a clamping element for clamping the cable. This clamping element is here designed in particular as a strain relief for the cable, and detachably connected with the sealing collar housing. The clamping element transfers the tensile forces acting on the cable to the housing. 
     The clamping element preferably lies on the outside of the casing of the first seal. In this way, the cable is also relieved of tensile forces in the area of the first seal. 
     In this way, an irregular application of force on the cable along the periphery caused by tensile stress is also avoided in the area of the first seal via one of the aforementioned options for cable strain relief. As a result, a uniform application of force on the cable along the periphery ensures a permanently high sealing action by the first seal. 
     The clamping element in the submersible motor preferably comprises a surface that circumferentially surrounds the feed-through for the cable and has circumferentially arranged ribs. In particular such circumferentially oriented ribs prevent strain on the cable along the longitudinal axis of the feed-through. It is especially preferred that the clamping element here is designed as a clamping ring formed of two circumferentially arranged ring sections that can be exposed to a force relative to each other. In this way, the cable is detachably engaged by the clamping element, so that the cable can be easily detached from the sealing collar. In particular, these ring sections comprise mutually opposing surfaces extending radially outward from the inner periphery, which can be bolted together and/or with the sealing collar housing. 
     In an advantageous further development of the present invention, the second seal in the submersible motor has at least one sealing ring, which is arranged on the outer periphery of the sealing collar, and abuts the inner periphery of the inlet. In another preferred embodiment of the present invention, the sealing ring can also be arranged on the inner periphery of the inlet, and designed to abut the outer periphery of the sealing collar. As an alternative, the second seal can also lie axially between the housing of the submersible motor and a portion of the sealing collar, and be arranged either on the submersible motor housing or the sealing collar. 
     It is further preferred that the submersible motor comprises an electromagnetic shield for the cable on an axial section of the feed-through that leads into the housing viewed from the first seal. The electromagnetic cable shield preferably comprises a rim of metal tongues, which extend radially inwardly from the sealing collar housing, and abut the outer periphery of the cable, curved inwardly relative to the housing at an acute angle. 
     The submersible pump according to a preferred embodiment of the present invention includes a submersible motor according to the present invention. The submersible motor preferably lies along with other constituents of the submersible pump in a shared submersible pump housing, i.e., the submersible motor housing is formed by the submersible pump housing. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG. 1  is a simplified elevational view of a submersible pump with a submersible motor in a shared housing with a watertight cable feed-through according to a preferred embodiment of the present invention; 
         FIG. 2  is a cross-sectional longitudinal view of the housing of the submersible pump according to  FIG. 1  with the watertight cable feed-through; 
         FIG. 3  is a cross-sectional longitudinal view of the sealing collar of the cable feed-through according to  FIG. 2  in accordance with a first preferred embodiment of the present invention; 
         FIG. 4  is an axial top view of the sealing collar according to  FIG. 3 , viewed entering the housing; 
         FIG. 5  is an axial top view of the sealing collar according to  FIG. 3 , viewed exiting the housing; 
         FIG. 6  is a radial top view of the sealing collar according to  FIG. 3 ; 
         FIG. 7  is a perspective view of the sealing collar according to  FIG. 3 ; 
         FIG. 8  is a perspective view of the sealing collar according to  FIG. 3 ; and 
         FIG. 9  is a cross-sectional view of sealing collar of a watertight cable feed-through of a submersible pump according to a second preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain terminology is used in the following description for convenience only and is not limiting. The word “front” designates a direction in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the device, and designated parts thereof, in accordance with the present invention. Unless specifically set forth herein, the terms “a,” “an” and “the” are not limited to one element, but instead should be read as meaning “at least one.” The terminology includes the words noted above, derivatives thereof and words of similar import. 
     Referring to the drawings in detail, wherein like numerals indicate like elements throughout the several views, a submersible pump  1  shown on  FIG. 1  preferably includes a submersible motor  2 , and is arranged with the latter in a shared housing  3 . Therefore, the housing  3  simultaneously consists of the housing  3  of the submersible pump and housing  3  of the submersible motor  2 . As illustrated on  FIG. 2 , a wall  4  of the housing  3  is provided with a watertight cable feed-through, which comprises an inlet  5  in the wall  4  and a sealing collar  6 . 
     The sealing collar  6  shown in  FIG. 2-8  preferably includes an essentially rotationally symmetrical sealing collar housing  10 . A feed-through  20  extends along the longitudinal axis  15  of the sealing collar housing  10 , and includes a circular cross section at each axial section. A cable  25  can be guided through the feed-through  20 , using the sealing collar  6  to pass through the wall  4  of the submersible pump housing  3  and inside the submersible pump  1 . 
     In order to secure the sealing collar  6  to the wall  4 , the sealing collar  6  preferably includes a complete projection  30  along the outer periphery of the sealing collar housing  10 , which extends radially outwardly, away from the sealing collar housing  10 . The projection  30  of the sealing collar housing  10  includes an abutment surface  35 , which comes to abut the wall  4  as the sealing collar  10  is being mounted thereto. Screws  40  are used to detachably screw the projection  30  with the wall  4  of the housing  3 . The projection  30  thereby divides the sealing collar housing  10  into two axial sections: an axial section provided for accommodation outside the housing  3  of the submersible pump  1 , as well as a second axial section of the sealing collar  6 , which lies inside the inlet  5  in the wall  4  of the pump housing  3  or inside the pump housing  3 . 
     To ensure that the cable  25  comes to tightly abut in the feed-through  20 , the sealing collar  6  preferably includes a first seal in the form of a sealing ring  45 , which completely surrounds the axis  15  of the feed-through  20 . The inner peripheral surface  50  of the sealing ring  45  here abuts the outer peripheral surface of the cable  25 . The outer periphery of the seal  45  is surrounded by a sleeve  55 , which forms part of the sealing collar housing  10 . The sleeve  55  ends in a direction  60  outside the housing as viewed from the sealing ring  45  in a front wall  65 , which continues the projection  30  radially inwardly toward the longitudinal axis  15 . 
     In an axial direction  60  outside the housing, the sealing ring  45  abuts a thin and flat plate  75 . The plate  75  here lies on the inside  70  of the front wall  65  of the sleeve  55 , and preferably includes a first of two clamping surfaces for the first seal. The plate  75  essentially extends radially to the longitudinal axis  15  of the sealing collar  6 , and completely surrounds the latter. To this end, it comprises a central opening oriented coaxially with the feed-through  20 . In the direction  80  into the housing, the sealing ring  45  abuts a second plate  85 , which preferably includes the second of the two clamping surfaces. The second plate  85  is thin and flat in design like the first plate  75 , and essentially extends radially and circumferentially around the longitudinal axis  15  of the sealing collar  6 . The plate  85  here also comprises a central opening oriented coaxially with the feed-through  20 , through which the cable  25  can be passed. 
     The two plates  75 ,  85  are used to apply force to the sealing ring  45  in the assembled state of the sealing collar  6  shown on the figures, pushing it radially into the feed-through  20 , i.e., against the outer periphery of an inserted cable. To this end, the plate  85  is exposed to a force in the axial direction along the longitudinal axis  15  toward the plate  75 , so that the elastic sealing ring  45  is clinched in an axial direction. The sleeve  55  prevents the material of the sealing ring  45  from expanding outwardly in a radial direction. Therefore, axially clinching the sealing ring  45  causes it to inwardly expand in a radial direction into the feed-through  15 . As a consequence, the axial clinching results in an application of force on the cable  25  by the first seal directed toward the longitudinal axis  15  of the sealing collar  6 . 
     The axial force on the plate  85  toward the plate  75  is applied by a compression spring designed as a disk spring packet  90 , which consists of several disk springs  95 . The disk spring packet  90  is here oriented in such a way that the compressive force it exerts acts in the direction of the longitudinal axis  15  of the sealing collar  6 . The disk spring packet  90  is essentially designed with the same outer periphery as the elastic sealing ring  45  of the first seal, and like the latter abuts the inner periphery of the sleeve  55 . The disk spring packet  90  comprises a central recess  100  oriented coaxially to the longitudinal axis  15  of the feed-through  20 , through which the cable  25  can be guided. The disk spring packet  90  in conjunction with the plates  75  and  85  as well as the sleeve  55  is here a constituent part of the means for applying a force to the sealing ring  45 . The disk spring packet  90  is axially clinched, and hence pre-stressed for exerting a compressive force. As a result, the disk spring packet  90  can compensate an axial change in length of the sealing ring  45 , so that the plate  85  always abuts the sealing ring  45  under a pressure. In this embodiment, the sealing ring  45  is hence also exposed to a compressive force when the elastic material of the sealing ring  45  loses elasticity as time passes, undergoing plastic deformation and possibly becoming axially shorter in the process. 
     The disk spring  90  is supported in the direction  80  into the housing against a projection  105  extending axially along the inner circumferential surface  50  of the sleeve  55 . On the radially inner side of the sleeve  55 , the projection  105  projects completely out of a cover plate  110 , which seals the front side of the sleeve  55  in a direction  80  into the housing. The cover plate  110  is detachably screwed to the sleeve  55  by means of screws  115 . When tightening the cover plate  110  to the sleeve  55 , the projection  105  shifts axially into the sleeve  55 , and axially clinches the disk spring  90 . Therefore, the latter exerts a compressive force on the plate  85 . By mounting the cover plate  110 , the disk spring  90  is suitably pre-stressed to exert the compressive force on the plate  85 , and hence on the sealing ring  45 . 
     In addition, the sealing collar  6  is detachably and tightly secured to the wall  4  of the housing  3  of the submersible pump  1 . To this end, two sealing rings  120 ,  125  are attached to the sleeve  55  of the sealing collar housing  10  near the projection  30 . The two sealing rings  120 ,  125  are slightly axially offset relative to each other, and circle around the respective outer periphery of the sleeve  55  of the sealing collar housing  10 . In order to axially lock in place the sealing rings  120 ,  125 , the latter are clamped in circumferentially running grooves  130 ,  135  around the sleeve  55 . If the sealing collar  6  is attached to the wall  4  of the housing  3  of the submersible pump  1  as shown in  FIG. 2 , the two sealing rings  120 ,  125  come to abut the inside  140  of the inlet  5  in an axially tight manner. 
     In the direction  60  out of the housing, a clamping element in the form of a clamping ring  145  adjoins the projection  30 . To this end, the this axial section of the sealing collar housing  10  has two recesses  150  resembling circular segments, which lie on radially opposing sides of the feed-through  20 . The two-part clamping ring  145  is incorporated into these recesses  150 . The projection  30  or front wall  65  of the sleeve  55  is connected with the part of the sealing collar housing  10  lying on the opening  155  facing outwardly out of the housing via two narrow webs  160 , which are situated diametrically opposite each other on the feed-through  20  and separate the two recesses  150  from each other. 
     The clamping ring  145  surrounds two semi-complete rings  175 ,  180 , which are connected with the webs  160  to clamp the cable  25 . To this end, the webs  160  comprise threads, onto which the rings  175 ,  180  are bolted down by means of screws  195 ,  200 . In the bolted state, the inner diameter of the resultant clamping ring  145  has a smaller diameter than the cable  25  not exposed to a force. For this reason, the cable  25  is axially rigidly locked in place in the feed-through  20  by the clamping ring  145  screwed to the webs  160 . In addition, the inner periphery of the clamping ring  145  comprises a profiled clamping surface  205 . The profile of the clamping surfaces  205  is formed by clamping ribs  210 , which extend in the circumferential direction, and prevent the cable  25  from shifting axially. 
     The clamping ring  145  establishes a strain relief for the end of the cable  25  lying in the housing  3  of the submersible pump  1 . In this way, tensile forces, meaning forces acting in a direction  60  out of the housing and applied to the cable  25  outside the housing  3 , do not place a load on the end of the cable  25  inside the housing. Therefore, the electrical terminal contacts lying at the end of the cable  25  inside the housing are protected against tensile forces applied to the cable  25 . These tensile forces instead act on the sealing collar housing  10  via the clamping ring  145 . In addition, the clamping ring  145  also lies outside the housing of the sealing ring  45  of the first seal. As a result, in particular no tensile forces, especially no asymmetrical forces oriented at an angle to the longitudinal axis  15  of the feed-through  20 , act on the sealing ring  45  of the first seal. Therefore, the clamping ring  145  simultaneously also ensures a permanently high sealing action of the sealing ring  45 . 
     In addition, the opening  215  of the sealing collar  5  facing into the housing comprises an electromagnetic shield  220 , which comprises a rim of metal tongues  225 . The tongues  225  are distributed circumferentially around the longitudinal axis  15  of the sealing collar  5 . The tongues extend radially into the feed-through  20 , provided no cable  25  is situated therein. However, routing a cable  25  through bends the tongues  225  from the radial direction to an axial direction into the housing, so that the tongues  225  grindingly abut the outer circumferential surface of the cable  25  at an acute angle. 
       FIG. 9  shows another preferred embodiment of a sealing collar  6 ′ of a submersible pump according to the present invention. This sealing collar  6 ′ is designed similarly to the sealing collar  6  of the first preferred embodiment described above, but differs from the latter in that the sealing collar  6 ′ preferably includes a two-part seal within the sleeve  55 ′ instead of a clamping ring  145 . Provided there in place of the sealing ring  45  of the first seal is a sealing ring  45 ′ abutting the disk spring  90  as the first seal, and another sealing ring  230  away from the latter outside the housing as the third seal. The latter abuts between the sealing ring  45  and the plate  75  frontally lying on the front side  65  of the sleeve  55 ′. The two sealing rings  45 ′,  230  are separated from each other by another flat, circular plate  235 , which is designed and oriented identically to the plates  75  and  85 . 
     This preferred embodiment establishes a frictionally tight connection between the cable  25  and sealing collar housing  10 ′ outside the housing relative to the first seal. In this way, tensile forces acting on the cable  25  can be completely transferred to the sealing collar housing  10 ′ via the third seal. This makes it possible to forego additional clamping elements, such as the clamping ring  145  described above. As a consequence, the sealing ring  230  of the third seal represents an alternative embodiment for a strain relief lying together with the sealing ring  45 ′ of the first seal inside the sleeve  55 ′. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.