Patent Publication Number: US-2020300237-A1

Title: Medical suction pump

Description:
TECHNICAL FIELD 
     The present invention relates to a medical suction pump, in particular a motorized medical suction pump. Suction pumps of this kind are in particular breast pumps for expressing human breastmilk or drainage pumps for aspirating body liquids, for example for chest drainage or for wound drainage. 
     PRIOR ART 
     Medical suction pumps, also called vacuum pumps, are known for a wide variety of uses. For example, they are used as breast pumps for expressing human breastmilk or as drainage pumps for aspirating body liquids. Such suction pumps have piston pumps or diaphragm pumps as a pump assembly. The use of a pump diaphragm has the advantage that the suction pump as a whole can be made relatively small and light and therefore portable during use. A motorized pump assembly that is very small but nevertheless satisfies the strict demands placed on a breast pump is disclosed in WO 2006/032156 A1. Portable suction pumps usually also have an energy accumulator for operating a motor of the pump assembly. The size of the energy accumulator and the size of the pump assembly thus substantially determine the size of the pump housing. 
     A further requirement of such suction pumps concerns sound damping. The pump assembly is often quite noisy, and rhythmically recurring noises disturb the user. It is therefore known to embed the pump assembly in a sound-attenuating or sound-damping environment. In this text, sound attenuating and sound damping are treated as equal and are each designated as sound-damping. 
     WO 2017/157691 A1 discloses a medical suction pump with an elastic bearing of the pump assembly inside a pump housing. 
     The pump assembly in WO 2015/109934 A1 is arranged in a closed inner housing, and a battery is arranged, parallel to the inner housing, in an outer pump housing. 
     The pump assembly in WO 2017/140562 A1 is secured in an outer pump housing by means of springs. 
     DISCLOSURE OF THE INVENTION 
     It is therefore an object of the invention to make available a medical suction pump which, while being as compact as possible, is also robust. 
     This object is achieved by a motorized medical suction pump having the features of Patent Claim  1 . 
     The motorized medical suction pump according to the invention has a pump assembly for generating an underpressure, a pump assembly carrier for supporting the pump assembly, and a seat for receiving an energy accumulator, wherein the pump assembly arranged in the pump assembly carrier defines a first longitudinal axis and the seat defines a second longitudinal axis. According to the invention, the pump assembly carrier forms the seat, and the second longitudinal axis extends at an angle to the first longitudinal axis. 
     By means of the pump assembly carrier forming the seat for the energy accumulator, and by virtue of the angled arrangement of pump assembly and energy accumulator, there are practically no empty spaces present, and the size of the suction pump as a whole is minimized. Since pump assembly and energy accumulator are held by the same pump assembly carrier, the device as a whole is relatively stiff. This not only increases the robustness of the device, it also minimizes vibrations during the operation of the pump assembly and thus reduces the generation and transmission of noise. 
     In preferred embodiments, the pump assembly carrier is designed substantially as a frame. The frame can have any desired shape. However, it preferably has a substantially elongate, rounded basic shape, in particular an elliptic or oval basic shape. The design as a frame permits a lightweight structure and additionally increases the stiffness. Moreover, a minimum of material is needed, which correspondingly reduces the production costs. The frame is preferably formed in one piece. It is preferably produced by plastic injection moulding. 
     Preferably, the suction pump comprises a first pump housing part and a second pump housing part, wherein the pump assembly carrier is held between the first pump housing part and the second pump housing part. It is thus fixed in its position, and its stiffness is increased. 
     In preferred embodiments, the pump assembly carrier forms a part of the pump housing. It preferably forms a connection part, visible from the outside, between the first pump housing part and the second pump housing part. This makes assembling the individual components easier, and a further bearing of the pump assembly carrier inside the pump housing can thereby be avoided. 
     The entire pump assembly carrier is preferably formed in one piece. 
     In preferred embodiments, at least two elastic bearings are present for supporting the pump assembly in the pump assembly carrier. In this way, it is possible to minimize or avoid the transmission of vibrations and structure-borne sound from the pump assembly to the pump assembly carrier and thus to the pump housing. Moreover, the pump assembly is thus held in a defined position and yet suspended flexibly, such that the noise development is reduced and/or damped. A two-point support is preferably present. However, it is also possible to use a three-point or multi-point support. The bearings are preferably formed from an elastomer. 
     Preferably, at least a first of these bearings forms a vacuum port. At least a second of these bearings, which preferably forms the counterbearing to the first bearing, is preferably arranged at a motor-side end of the pump assembly and in a continuation of a motor shaft of the pump assembly, i.e. in the alignment of the motor shaft. 
     Preferably, exactly two bearings are present, which are arranged at opposite ends of the pump assembly along the first longitudinal axis. These two bearings are preferably mutually offset with respect to the first longitudinal axis. The use of exactly two elastic bearings and/or said arrangement of the bearings minimizes the size of the suction pump as a whole and additionally has the effect that vibrations and structure-borne sound can only propagate to a limited extent, if at all. 
     The sound damping is optimized if the pump assembly is arranged in a sound-damping housing, and the sound-damping housing is held in the pump assembly carrier. 
     Preferably, an air inlet opening is present which is covered by a sound-damping element. The air inlet opening is preferably arranged in the sound-damping housing, which minimizes hissing noises when the ambient air is sucked in. The sound-damping element is preferably made of foam or of another suitable porous or air-permeable material. The pump housing is preferably made untight in a known manner, such that an air exchange from the interior of the pump housing to the environment and vice versa can take place at several places. 
     Preferably, the sound-damping housing has a case with a receiving opening for receiving the pump assembly, and a lid for closing the case, wherein the lid has a curved shape. This makes assembling the device easier and allows the sound-damping housing to be designed to take up as little space as possible. The case is preferably made of a stiff or semi-stiff material, in particular a plastic, and the lid is preferably made of a soft material. 
     Preferably, the sound-damping housing is supported in the pump assembly carrier by means of the at least two elastic bearings. Preferably, the at least two elastic bearings on the one hand support the sound-damping housing in the pump housing and on the other hand support the pump assembly inside the sound-damping housing. That is to say, the same bearings have dual functions, with each bearing preferably having corresponding surfaces or formations on two opposite sides. The number of bearings required is thus reduced. The bearing arrangement is precisely defined and optimized. Moreover, its requires little space and a minimum of component parts. The sound damping is improved, assembly is made easier and the production costs are minimized. 
     Preferably, the first bearing is a bearing module in the form of an elastic insert element, which is held in the sound-damping housing and passes through the latter. The entire insert element is preferably soft and produced in one piece, for example from silicone or TPE (thermoplastic elastomer). The insert element serves as a two-sided bearing and additionally closes the sound-damping housing. 
     Preferably, the second bearing is lid or a bearing module in the form of part of a lid of the sound-damping housing, wherein the entire lid is elastic. It is preferably made of a soft material, e.g. silicone or TPE. The stiffness of the bearing point can be defined by the chosen shape of the lid. The lid itself can form the second bearing or can form at least parts of this bearing. 
     Individual elements can also be combined, even without the angled arrangement of pump assembly and energy accumulator or without the arrangement of these two components on a common pump assembly carrier, in order to form other suction pumps according to the invention. Examples of these are given below and are likewise claimed as separate inventions. The preferred embodiments mentioned above, in particular the features of the dependent patent claims, can also be correspondingly combined with these examples without using all the features of Patent Claim  1 . 
     In a preferred embodiment likewise claimed as an invention, a medical suction pump has a pump housing, a pump assembly arranged in the pump housing for the purpose of generating an underpressure, and at least a first elastic bearing and a second elastic bearing for supporting the pump assembly in the pump housing. The first elastic bearing is located at a first end of the pump assembly, and the second elastic bearing is located at a second end of the pump assembly opposite the first end. The first elastic bearing forms a vacuum port. This arrangement takes up very little space and optimally reduces vibrations. 
     In another embodiment likewise claimed as an invention, a medical suction pump has a pump assembly, a sound-damping housing for receiving the pump assembly, and a pump housing for receiving the sound-damping housing. The sound-damping housing has a case for receiving the pump assembly, and a lid for closing the case. The lid is elastic and has an elastic bearing for supporting the sound-damping housing in the pump housing. This design makes assembling the device easy, since the pump assembly simply has to be pushed into the case. The elastic and in particular soft lid optimally prevents vibrations and the propagation of structure-borne sound. 
     In preferred embodiments, these two variants are combined with each other. That is to say, the first bearing forms the vacuum port and the second bearing forms the lid. 
     In a further preferred embodiment, which is likewise claimed as a separate invention, a medical suction pump has a pump assembly, a sound-damping housing for receiving the pump assembly, and a pump housing for receiving the sound-damping housing. At least a first elastic bearing and second elastic bearing are present, wherein at least one of these two elastic bearings on the one hand supports the sound-damping housing in the pump housing and on the other hand supports the pump assembly inside the sound-damping housing. Preferably, both elastic bearings support the sound-damping housing with respect to the pump housing and also the pump assembly with respect to the sound-damping housing. That is to say, both elastic bearings are preferably designed as modules which form bearing points at two opposite sides. As has already been mentioned above, the bearing arrangement and the sound damping are optimized here, and an extremely compact structure is permitted. This embodiment can be achieved, for example, if the lid and/or the vacuum port are designed as bearings and are in each case soft and flexible at the corresponding points or overall. 
     Further embodiments are set forth in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention are described below with reference to the drawings, which serve only for explanatory purposes and are not to be interpreted as limiting the invention. In the drawings: 
         FIG. 1  shows an exploded view of a suction pump according to the invention in a first embodiment; 
         FIG. 2  shows a first cross section through the suction pump according to  FIG. 1 ; 
         FIG. 3  shows a second cross section through the suction pump according to  FIG. 1 ; 
         FIG. 4  shows an exploded view of a sound-damping housing with a pump assembly of the suction pump according to  FIG. 1 ; 
         FIG. 5  shows a perspective view of a part of the suction pump according to  FIG. 1  without sound-damping element; 
         FIG. 6  shows a perspective view of a part of the suction pump according to  FIG. 1  with sound-damping element; 
         FIG. 7  shows a perspective view of a first bearing module of the suction pump according to  FIG. 1 ; 
         FIG. 8  shows a top view of the first bearing module according to  FIG. 7 ; 
         FIG. 9 a    shows a cross section through an attachment opening of the first bearing module according to  FIG. 7  in a first variant; 
         FIG. 9 b    shows a cross section through an attachment opening of the first bearing module according to  FIG. 7  in a second variant; 
         FIG. 9 c    shows a cross section through an attachment opening of the first bearing module according to  FIG. 7  in a third variant; 
         FIG. 10  shows a perspective view of a second bearing module of the suction pump according to  FIG. 1 ; 
         FIG. 11  shows a top view of the second bearing module according to  FIG. 10 ; 
         FIG. 12 a    shows a cross section through an attachment opening of the second bearing module according to  FIG. 11  in a first variant; 
         FIG. 12 b    shows a cross section through an attachment opening of the second bearing module according to  FIG. 11  in a second variant; 
         FIG. 12 c    shows a cross section through an attachment opening of the second bearing module according to  FIG. 11  in a third variant; 
         FIG. 12 d    shows a cross section through an attachment opening of the second bearing module according to  FIG. 11  in a fourth variant. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a preferred illustrative embodiment of a suction pump according to the invention. It is a breast pump for expressing human breastmilk. 
     The suction pump has a first pump housing part  1 , a sound-damping housing  2 , a pump assembly carrier  3 , a second pump housing part  4 , and a cover  5 . In the assembled state of the suction pump, the sound-damping housing  2  is located inside a pump housing, which is formed substantially by the first pump housing part  1 , the second pump housing part  4 , and the pump assembly carrier  3  arranged and clamped between these two parts  1 ,  4 . The pump assembly carrier  3  is therefore preferably visible from the outside as a circumferential strip. 
     The first pump housing part  1  forms the bottom of the suction pump. It has a shell-shaped base body  10 , of which the underside (facing upwards here) is almost flat and forms a support surface  11 . The base body  10  is oval in longitudinal section. First connection elements  12 , preferably snap-fit elements or other known connection means, are distributed at the circumference of the base body  10 . 
     The second pump housing part  4  has a substantially oval base plate  40  and a peripheral channel  43  for receiving the pump assembly carrier  3 . The electronic components customarily present in suction pumps are arranged on the base plate  40 . They are only indicated schematically here. A control and electronics unit is designated by reference sign  41 . Second connection elements  42 , which engage in the frame  30 , are distributed about the circumference of the second pump housing part  4 . 
     The cover  5  forms, together with the second pump housing part  4 , the upper part of the pump housing, even though these components are arranged at the bottom in this view. The cover  5  can be secured on the second pump housing part  4 . It preferably has a plane-parallel, stiff and oval cover plate  50  with a display/operation window  51 . By means of the display/operation window  51 , it is possible, for example, to input user data and to visually present the operating mode of the suction pump. 
     The pump assembly carrier  3  is preferably stiff or semi-stiff. It is preferably made of a plastic and is preferably in one piece. It has an oval frame  30 . At a narrow end face, the frame  30  transitions into an elevated end wall  31 , which has a through-opening  33 . The rear face of the end wall  31  is provided with a first bearing seat  36 , which surrounds the through-opening  33 . Third connection elements  32  are distributed about the circumference of the frame  30  and engage in the first pump housing part  1  in order to hold the pump housing together. 
     An energy accumulator seat  35  is arranged at the end of the frame  30  opposite the through-opening  33 . It is configured according to the shape of an energy accumulator  6 . In this example, the energy accumulator  6  is a cylindrical rechargeable battery. Other shapes and types of energy accumulators can also be used. The energy accumulator seat  35  is configured as a box that is open to the top in  FIG. 1 , with respective clip elements  34  protruding upwards on two opposite sides. All of these elements are preferably formed jointly in one piece with the frame  30 . 
     A second bearing seat  37  is formed adjacent to the energy accumulator seat  35 . In this example, this second bearing seat  37  is also configured as a rectangular, upwardly open box that is formed integrally on the frame  30 . The rear end of the frame  30  opposite the through-opening  33  is configured as a power supply connection  38 . This can be seen clearly in  FIGS. 2 and 3 . 
     The sound-damping housing  2  has a case  20  for receiving a pump assembly  7 . The case  20  is preferably stiff or semi-stiff and is in particular made of plastic. It preferably has an oval, rounded shape matching the shape of the pump housing, wherein the case  20  is bevelled in the region of its opening. The bevel is preferably curved, such that the case is step-shaped and longer on one side than on the other side. This can be seen clearly in  FIG. 1 . 
     This step-shaped edge is closed by means of a lid  21 . The lid  21  has a correspondingly curved closure body  210 . The latter transitions preferably in one piece into an approximately cylindrical transition region  211 . The diameter of this transition region  211  preferably corresponds approximately to the diameter of the longer region of the case  20 . The transition region  211  is followed by a connection pin  212 , which is adjoined by a second bearing module  23 . This can be seen clearly in  FIGS. 2 and 3 . A first bearing module  22  is located at the opposite end of the case  20  and is described in more detail further below in the text. 
     The second bearing module  23  can be plugged onto the connection pin  212 . However, it is preferably formed integrally with the latter and with the rest of the whole lid  21 . The lid  21  is preferably formed elastically with the second bearing  23 . It is soft in particular. It is preferably made of an elastomer or of silicone. 
     In the region of the first bearing module  22 , the case  20  has a recess  200 , which has a window  202  in the upper region. A sound-damping element  25 , here a foam cube, is arranged in this recess  200 . 
     The arrangement of the sound-damping housing  2  and of the energy accumulator  6  inside the frame  30  of the pump assembly carrier  3  can be seen clearly in  FIG. 2 . The sound-damping housing  2 , more precisely the case  20 , is supported in the first bearing seat  36  by means of the first bearing module  22 . The second bearing module  23  is located in the second bearing seat  37  of the pump assembly carrier  3 , such that the sound-damping housing  2  is also supported in the pump assembly carrier  3  at this opposite end. A two-point bearing is therefore present. 
     A through-opening of the first bearing module  22 , which here forms a vacuum port  24 , is in alignment with the through-opening  33  of the pump assembly carrier  3 , as can be seen clearly in  FIG. 3 . This through-opening  33  thus forms a seat for a plug of a suction hose, which leads to a breast shield for placing on the mother&#39;s breast. Plug, suction hose and breast shield are not shown here. However, they are well known from the prior art. 
     As can be seen from  FIG. 2 , the case  20  defines a first longitudinal axis L 1 , which is aligned with the longitudinal centre axis of the vacuum port  24 . The energy accumulator  6  defines a second longitudinal axis L 2 , which extends at an angle to this first longitudinal axis L 1 . The second bearing module  23  defines, with its longitudinal centre axis, a third longitudinal axis L 3 , which is parallel and offset with respect to the first longitudinal axis L 1 . 
     As can be seen clearly in  FIGS. 2 and 3 , the available room inside the pump assembly carrier is optimally utilized by virtue of the bevelling of the case  20  and by the oblique arrangement of the energy accumulator  6 , and empty spaces are largely avoided. The pump housing overall can be made very small and compact. It is sound-damped and yet stiff and robust. 
     The arrangement of the pump assembly  7  inside the sound-damping housing  2  is shown in  FIG. 3 . An exploded view matching this is found in  FIG. 4 . 
     Preferably, the pump assembly  7  corresponds substantially to the pump assembly described in WO 2006/032156 A1. However, other forms and designs can be used in the device according to the invention. The pump assembly, however, preferably comprises an electric motor and a pump unit, in particular a diaphragm pump, preferably a pump chamber with a pump diaphragm. 
     In the figures, the electric motor is designated by reference sign  70  and the pump unit by reference sign  71 . The third longitudinal axis L 3  of the second bearing module  23  forms the alignment of a motor shaft (not shown) of the electric motor  70 . The electric motor  70  is thus arranged adjacent to the second bearing module  23 . 
     The pump unit  71  has a vent  710 , a vacuum opening  711  and a ventilation opening  712 . This can be seen clearly in  FIG. 3 . 
     In the assembled state of the device, the ventilation opening  712  is adjacent to an air inlet opening  201 , which is located in the recess of the sound-damping housing  2 . This air inlet opening  201  can be seen clearly in  FIG. 5 . It is covered by the sound-damping element  25 , as is shown in  FIG. 6 . For reasons relating to injection moulding, a window  202  is present in the case  20 . 
     The vent  710  leads into the interior of the sound-damping housing  2 , more precisely of the case  20 . Air, which escapes from the pump unit  71  via this vent  710 , leaves the sound-damping housing  2  via leakage points, for example via a receiving element  26  of a plug connection to a plug-in element  213  of the lid  21 . 
     The vacuum opening  711  is aligned with a connection channel  222  of the first bearing module  22 , as can be seen in  FIG. 4 . In the interior of the first bearing module  22 , the connection channel  222  has an angled profile, i.e. a non-rectilinear profile, and terminates in the vacuum port  24 , more precisely in the attachment opening  225  present in the latter. This attachment opening  225  can be seen clearly in  FIG. 7 . 
     The pump assembly  7  is supported in the sound-damping housing  2  at the vacuum side by means of the first bearing module  22  and is supported in the sound-damping housing  2  at the motor side by means of the second bearing module  23 , more precisely the lid  21 . For this purpose, the lid  21  simply has to be plugged onto the case  20  and plugged with the aforementioned plug-in elements  213  into the corresponding receiving elements  26 . 
     The first bearing module  22  is not, as shown in  FIG. 4 , located in front of the case  20  but instead located inside the case  20 . For this purpose, it can simply be pushed in via the curved opening and pushed partially through a through-opening  27  at the end face of the case  20 . An attachment body  221  protrudes from the opening, a neck  226  stands free, and a base body  220  seals off the interior of the case  20  on the inner face thereof. These parts can be seen clearly in  FIGS. 7 and 8 . A clamp element  223  in the form of a resilient tongue is preferably used to secure the base body  220  in the case  20 . This tongue  223  likewise seals off the interior of the case  20 . 
     The base body  220  has a ventilation channel  224  which creates the connection between the ventilation opening  712  of the pump unit  71  and the air inlet opening  201  of the case  20 . 
     The entire first bearing module  22  is formed in one piece and is preferably elastic, in particular soft. It thus forms bearing points at two opposite sides: at a first side between the sound-damping housing  2  and the pump assembly carrier  3  and thus the pump housing, and at an opposite side between the sound-damping housing  2  and the pump assembly  7 , more precisely the pump unit  71 . 
     The lid too is formed in one piece with the second bearing module  23  and is preferably elastic, in particular soft. It thus also forms bearing points at two opposite sides: at a first side between the sound-damping housing  2  and the pump assembly carrier  3  and thus the pump housing, and at an opposite side between the sound-damping housing  2  and the pump assembly  7 , more precisely the electric motor  70 . Since the pump assembly carrier  3  is part of the outer pump housing, a further bearing is not needed. 
     The sound damping or the vibration damping can be further optimized by suitable choice of the attachment opening  225 . Shapes of the kind shown in  FIGS. 9 a  to 9 c    have proven useful. The neck  226  of the first bearing module  22  is shown in cross section, and also the attachment opening  225  located therein. The cross sections of the neck  226  and the shapes of the attachment opening  225  can be combined with one another in any desired manner. In  FIG. 9 a   , the neck  226  is cross-shaped and the attachment opening  225  is round. In  FIG. 9 b   , the neck  226  and the attachment opening  225  are oval, and in  FIG. 9 c    they are round. The combination according to  FIG. 9 b    is most preferred. 
       FIGS. 10 to 12   d  show the lid  21  with the second bearing module  23 . As has already been described, it has the curved closure body  210 , the transition region  211 , the connection pin  212  and the second bearing module  23 . The second bearing module  23  preferably has a cuboid frame with connection struts extending therein. It is thus elastic and adapts optimally to its associated second bearing seat  37 . 
     Cable feedthroughs  214  in the form of through-openings are preferably present in the transition region  211  in order to connect the electric motor  70  to the control and electronics unit  41  via the base plate  40 . The plug-in elements  213  are formed integrally on the curved closure body  210 . 
     The sound damping and the bearing arrangement can be additionally optimized through the configuration of the connection pin  212 . Preferred variants are shown in  FIGS. 12 a  to 12 d   . The connection pin  212  is preferably solid. It is preferably relatively stiff. 
     Its cross section is cross-shaped in  FIG. 12 a   , round in  FIG. 12 b   , rectangular in  FIG. 12 c    and oval in  FIG. 12 d   . It is preferably cross-shaped. 
     The suction pump according to the invention is small and compact and has good sound damping. 
     
       
         
           
               
             
               
                   
               
               
                 LIST OF REFERENCE SIGNS 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1 
                 first pump housing part 
               
               
                 10 
                 shell-shaped base body 
               
               
                 11 
                 support surface 
               
               
                 12 
                 first connection element 
               
               
                 2 
                 sound-damping housing 
               
               
                 20 
                 case 
               
               
                 200 
                 recess 
               
               
                 201 
                 air inlet opening 
               
               
                 202 
                 window 
               
               
                 21 
                 lid 
               
               
                 210 
                 curved closure body 
               
               
                 211 
                 transition region 
               
               
                 212 
                 connection pin 
               
               
                 213 
                 plug-in element 
               
               
                 214 
                 cable feedthroughs 
               
               
                 22 
                 first bearing module 
               
               
                 220 
                 base body 
               
               
                 221 
                 attachment body 
               
               
                 222 
                 connection channel 
               
               
                 223 
                 clamp element 
               
               
                 224 
                 ventilation channel 
               
               
                 225 
                 attachment opening 
               
               
                 226 
                 neck 
               
               
                 23 
                 second bearing module 
               
               
                 24 
                 vacuum port 
               
               
                 25 
                 sound-damping element 
               
               
                 26 
                 receiving element 
               
               
                 27 
                 through-opening 
               
               
                 3 
                 pump assembly carrier 
               
               
                 30 
                 frame 
               
               
                 31 
                 end wall 
               
               
                 32 
                 third connection element 
               
               
                 33 
                 through-opening 
               
               
                 34 
                 clip element 
               
               
                 35 
                 energy accumulator seat 
               
               
                 36 
                 first bearing seat 
               
               
                 37 
                 second bearing seat 
               
               
                 38 
                 power supply connection 
               
               
                 4 
                 second pump housing part 
               
               
                 40 
                 base plate 
               
               
                 41 
                 control and electronics unit 
               
               
                 42 
                 second connection element 
               
               
                 43 
                 channel 
               
               
                 5 
                 cover 
               
               
                 50 
                 cover plate 
               
               
                 51 
                 display window/operating window 
               
               
                 6 
                 energy accumulator 
               
               
                 7 
                 pump assembly 
               
               
                 70 
                 electric motor 
               
               
                 71 
                 pump unit 
               
               
                 710 
                 vent 
               
               
                 711 
                 vacuum opening 
               
               
                 712 
                 ventilation opening 
               
               
                 L 1   
                 first longitudinal axis 
               
               
                 L 2   
                 second longitudinal axis 
               
               
                 L 3   
                 third longitudinal axis