Patent Publication Number: US-2023148819-A1

Title: Filter unit for the intake connector in the dirty-water tank of a floor-cleaning machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of European Patent Application No. 21208487.5 filed Nov. 16, 2021, the disclosure of which is incorporated by reference as if fully set forth in detail herein. 
     FIELD 
     The present disclosure relates to a filter unit for the intake connector or suction connector in the dirty-water tank of a floor-cleaning machine, and to a floor-cleaning machine, in particular a scrubber dryer, having such a filter unit. 
     BACKGROUND 
     Floor-cleaning machines, or scrubber dryers, known from the prior art that can be moved by means of a chassis over a floor surface to be cleaned have a brush head which is provided with driven brushes which can engage with the floor surface to be cleaned, wherein, in the region of the brush head, cleaning liquid is applied to the floor surface to be cleaned in order for dirt adhering thereto to be detached. Behind the brush head as seen in the direction of travel of the scrubber dryer, there is then normally arranged a so-called suction foot, with the aid of which cleaning liquid applied beforehand to the floor surface to be cleaned can be extracted by suction again into a dirty-water tank of the machine. For this purpose, provision is made of a suction turbine which is connected via an intake connector to the interior of the dirty-water tank in order to generate negative pressure therein, wherein further a suction line leads from the interior of the dirty-water tank to the suction foot, so that, by way of the suction turbine, a suction region of the suction foot is subjected to negative pressure. This in turn leads to it being possible for a suction-air stream from the suction foot into the dirty-water tank to be generated, by way of which cleaning liquid situated on the floor surface to be cleaned is entrained into the dirty-water tank. 
     Here it is disadvantageous if foam, dirty water itself and dirt particles contained in the dirty water or in the suction-air stream pass into the suction turbine, since both can lead to damage to the suction turbine or to an electric motor driving said suction turbine. It is therefore also known from the prior art for provision to be made on the intake connector of a filter unit which prevents at least dirt particles from passing into the intake connector and thus the suction turbine. Furthermore, it is also known for provision to be made at the intake connector of a float valve which closes off the intake connector if the liquid level in the dirty-water tank has reached a predefined maximum level. 
     However, such filter units and float valves known from the prior art have proven to be disadvantageous because it is often not ensured that the filter unit is also re-fitted in the correct manner by a user, so that, after a cleaning process, the filter unit is correctly positioned with the float valve and prevents the passage of dirt or cleaning liquid toward the suction turbine. Moreover, the filter units and float valves known from the prior art do not reliably prevent entry of foam into the suction turbine. 
     It is therefore one object of the present disclosure to provide a filter unit with valve for the intake connector in the dirty-water tank of a floor-cleaning machine that is reliable and easy to fit. Furthermore, it is desirable that it also reliably prevents entry of foam into the suction turbine. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form, the disclosure provides a filter unit with valve for the intake connector in the dirty-water tank of a floor-cleaning machine that is reliable and easy to fit. Furthermore, it is desirable that it also reliably reduce or eliminate entry of foam into the suction turbine. 
     In some examples, a filter unit for a suction connector of a floor-cleaning machine is provided in having a suction connector in the dirty-water tank of the floor-cleaning machine. The filter unit has a substantially sleeve-shaped main body, which extends between a first face end and a second face end and has an inlet opening at the first face end. The filter unit furthermore has a substantially annular float body, which is arranged around the main body and is displaceable along the main body between a closed position and an open position. The filter unit furthermore has a cover, which is arranged on the first face end of the main body, wherein the cover has at least one entry opening which is configured to be closed off by the float body when the latter is in the closed position and which is open when the float body is at a distance from the closed position. Provision is made in the cover of a fluid channel, which is configured to allow a fluid to flow from the entry opening into the inlet opening. The filter unit furthermore has a sleeve-shaped filter element, which is arranged around the main body in such a way that, between the main body and the filter element, there is formed an annular space in which the float body is arranged so as to be displaceable between the closed position and the open position. The filter element is formed at least partially from a filter material such that a fluid can pass through the filter material, while particles contained in the fluid are separated out at the filter material. The filter material may be arranged on a circumferential surface of the filter element. 
     In some forms, a float valve can be easily mounted onto the intake connector in the dirty-water tank of a scrubber dryer in that the sleeve-shaped main body is pushed over the intake connector. 
     Optionally, the main body can be part of the intake connector and possibly even formed in one piece therewith. 
     When the level in the dirty-water tank increases during and as a consequence of the operation of the floor-cleaning machine and, in the process, increasingly raises the float body in the annular space, the float body can close off the entry opening (closed position). Closure of the entry opening then prevents dirty water from passing from the dirty-water tank into the suction turbine situated downstream and damaging the latter. When the entry opening has been closed off by the float body, this can be indicated to the user of the scrubber dryer, wherein firstly it is possible that the motor current of the suction turbine, which drops as a result of the closure, leads to a corresponding signal for the user being produced. Secondly, it is also conceivable for a switch or a contactless sensor to be actuated by the float valve and, in this way, for a corresponding signal for the user to be generated. 
     A similar effect is also achieved if, during the travel of the scrubber dryer, the level in the dirty-water tank varies greatly, and the float body is raised to a great extent only for a short time. Then, likewise, the entry opening is closed off, and this can be indicated to the user. In such a case, too, it is ensured that no dirty water passes to the suction turbine. 
     Additionally, the filter element, which surrounds the annular space and the main body, prevents dirt particles contained in the suction-air stream from being able to pass through the entry opening and an opening to the suction turbine. When the filter element or the filter material provided thereon is so dirty that only a small air stream passes through, this can also lead to the float body being drawn against the entry opening and closing off the latter. This can then be indicated to the user by means of the possibilities already described. 
     Since the float body is arranged in the annular space and is guided by the main body, a compact construction is the result overall, and the float body is held captively on the main body such that, if the filter element is dismounted for cleaning purposes, said float body cannot be lost, which would have the consequence that, after a recommencement of operation after the cleaning of the filter element, the closing action, with too high a level in the dirty-water tank, would no longer be provided and dirty water could enter the suction turbine without hindrance. 
     In some forms, the filter element can be held in a detachable manner on the cover. The filter element can be pulled off from the cover, cleaned and remounted. The filter element may in this case furthermore preferably have a grip, wherein detachment from the cover can be simplified. A dimension or inner diameter of the filter element can be matched to the cover in such a way that the filter element is held on the cover by way of a transition fit, or slight press fit, in order to prevent loss for example during tilting of the dirty-water tank for servicing purposes. This embodiment is particular easy to fit and/or to service. 
     In some forms, the main body can have an encircling flange which extends away in an outward direction and against which the float body bears when the float body is in the open position, and the filter element extends as far as the flange. The flange may serve as a stop during the mechanical connection of the filter element, in particular after a cleaning process. Moreover, the flange can prevent a partial stream of the suction-air stream from entering the annular space while bypassing the filter element. 
     In some forms, the flange may have at least one opening or flange opening which is closed off by the float body when the float body is in the open position and which is opened up when the float body has been displaced from the open position toward the closed position. This flange opening can offer a further flow channel into the annular space, and a flow through this flange opening can facilitate a transfer of the float body into the closed position. In particular if the filter element has become increasingly dirty, or if foam forms in the dirty-water tank, then the flange opening can increase the protective action by the filter unit. This embodiment can make it possible that, in the case of a clogged filter element, air can flow through the flange opening and said air can displace the float body into its closed position. Finally, the flange opening additionally makes it possible that foam possibly situated in the dirty-water tank moves the float body also in the direction of the closed position. In this way, it is thus achieved that foam, which forms above the dirty-water level and would present a risk to the suction turbine, also leads to closure of the entry opening by way of the float body, which protects the suction turbine and is in turn indicated to a user. 
     In the region of the inlet opening, the main body can have at least one latching element, preferably at least one latching hook. The at least one latching element is configured to engage with at least one engagement element at the suction connector. The main body and the cover are configured in such a way that, when the at least one latching element is in engagement with the engagement element, a fluid connection between the entry opening and the suction connector is provided. The main body and the cover may be configured in such a way that, when the at least one latching element is in engagement with the engagement element of the suction connector, a fluid can flow into the suction connector through the entry opening of the cover and through the inlet opening of the main body. In this embodiment, the filter element can be simply attached to a suction connector. 
     In some forms, a locking body may be provided, wherein the locking body has a cylindrical portion, and wherein the cylindrical portion is inserted into the inlet opening and is configured to counteract action of bringing the latching element out of engagement with respect to the suction connector. In this embodiment, after the insertion of the locking body, the main body is in a state fixedly connected to the suction connector. Moreover, the locking body can counteract leaks between main body and intake connector. 
     In some forms, the locking body may have an encircling collar which extends beyond the main body into the annular space. The float body may bear against the collar in the closed position. The collar may contribute to the definition of the closing position. The cover may be mechanically connected to the first face end of the main body, and clamp the collar of the locking body in the process. 
     In some forms, the cover and the main body may be components which are separate from one another, wherein the locking body, in particular the collar thereof, is arranged between the cover and the main body. In this embodiment, the filter unit may be fitted in such a way that, firstly, the main body is mounted onto the intake connector, wherein the latching elements engage with the intake connector. Then, the locking body is inserted into the inlet opening of the main body such that detachment of the latching elements from the intake connector is prevented and the main body is thus locked to the intake connector. Subsequently, the cover is fastened to the main body such that the locking body can then no longer be detached from the main body. The main body can then be detached from the intake connector only if, beforehand, the cover is removed and then the locking body is removed from the inlet opening. This construction thus makes it possible in a simple manner for the main body to be securely fastened to the intake connector. Furthermore, the collar of the locking body secures the float body against separation from the main body and loss if the filter element, for example for the purpose of cleaning the cover and the main body, is pulled off. 
     In some forms, an elastic ring element is provided which bears against a surface of the main body facing away from the cover, wherein the ring body is provided to bear against the suction connector. This embodiment is more resistant to vibrations during the operation of the floor-cleaning machine. The elastic ring element may moreover serve to compensate for manufacturing tolerances, in particular of the main body and the suction connector. Furthermore, the elastic ring element prevents leaks, in particular between the suction connector and the main body. 
     Optionally, the filter element has a sieve-like circumferential surface. This allows the cleaning of the filter element to be simplified. 
     In some forms, the main body has a tubular portion around which the float body can be arranged, wherein the tubular portion can be fitted over a suction connector of a floor-cleaning machine. Said main body can be arranged and centered relative to the suction connector in a simple manner. 
     In some forms, the filter unit is incorporated into a scrubber-dryer having a dirty-water tank, a suction connector, which extends into the dirty-water tank, a suction turbine, which is fluidically connected to an end of the suction connector that is remote from the dirty-water tank and which serves for generating negative pressure in the dirty-water tank, a suction line, which ends in the dirty-water tank and which is connected to a device for receiving liquid, by way of negative pressure, from a floor surface to be cleaned. In the case of said floor-cleaning machine, provision is made of one of the above-described filter units, which is mechanically connected to that end of the suction connector which is arranged in the dirty-water tank. 
     In some forms, the floor cleaning machine has a chassis by way of which it can be moved over a floor surface to be cleaned, wherein furthermore preferably provision is made at the machine of a cleaning device which can come into engagement with the floor surface to be cleaned and by way of which cleaning liquid can be applied to the floor surface. 
     In this context, it should be pointed out that the present invention may be used both for self-driving floor-cleaning machines or scrubber dryers, in the case of which a user rides on the machine, and for machines in the case of which a user walks in front of the machine or behind the machine. 
     The floor-cleaning machine may have a current sensor which can detect the current intensity of the electric current consumed by the suction turbine. 
     During the operation of said floor-cleaning machine, the fill level in the dirty-water tank can exceed a maximum value, an undesired volume of foam can form in the dirty-water tank, and/or the filter element of the filter unit can become increasingly clogged. In these cases, the float body, in particular because of the opening in the flange of the main body, can assume the closed position and prevent undesired ingress of liquid into the suction turbine. In the case of the closed position being assumed, the current consumption of the suction turbine is changed and, in particular, it is possible to recognize the change in current in a current-time curve as a kink or as a discontinuity. Owing to this change in current, a signal may be indicated to a user, and, in response to this signal, a user should service the floor-cleaning machine, that is to say clean the filter and/or empty the dirty-water tank. However, it is also conceivable for a switch or a contactless sensor to detect whether the float body is in the closed position. Here, too, a corresponding signal indicating the closure to the user can then be generated. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG.  1    is a view of a scrubber dryer with an exemplary embodiment of a filter unit according to the present disclosure in longitudinal section; 
         FIG.  2    is a view of an exemplary embodiment of the filter unit of  FIG.  1    in cross section; and 
         FIG.  3    is a perspective view of the exemplary embodiment of the filter unit of  FIG.  2   . 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
       FIG.  1    shows, as an embodiment of a floor-cleaning machine, a scrubber dryer  1  which has in its housing  3  a dirty-water tank  5  which can be closed off by a cover element  7  which is held in a pivotable manner on the housing  3 . The floor-cleaning machine  1  is furthermore provided with a chassis having wheels  9  such that the scrubber dryer  1  can be moved over a floor surface  11  to be cleaned. As can furthermore be gathered from  FIG.  1   , a brush head  13  is attached in a height-adjustable manner to the housing  3 , wherein, in the preferred exemplary embodiment shown here, the brush head  13  has brush elements  15  which are driven in rotation and which can engage with the floor surface  11  to be cleaned in order to detach dirt therefrom, wherein, during the cleaning process, cleaning liquid is applied to the floor surface  11  to be cleaned from a fresh-water tank  17  (schematically illustrated), which is likewise provided in the housing  3 . 
     As can also be gathered from  FIG.  1   , in the exemplary embodiment described here, a suction foot  19  is attached to the housing  3  of the floor-cleaning machine, which suction foot serves as a receiving device for cleaning liquid present on the floor surface  11  to be cleaned. The suction foot  19  is, in a manner known per se, configured in such a way that it has two sealing lips which are at a distance from one another and which, during cleaning operation, bear with an edge on the floor surface  11  to be cleaned, wherein the sealing lip facing in the direction of travel has inlet slits such that cleaning liquid applied beforehand can enter the region between the sealing lips. The region between the sealing lips is connected via a suction line  21  and an inlet connector  23  to the dirty-water tank  5 , wherein the inlet connector  23  projects into the dirty-water tank  5 . 
     The scrubber dryer  1  furthermore has a suction turbine  25  in the housing  3 , which suction turbine has a drive motor  27  and a fan wheel  29  (schematically illustrated) that is driven thereby, wherein the inlet of the suction turbine  25  is connected via a suction connector  31  to the interior of the dirty-water tank  5 , wherein the free end  33  of the suction connector  31  is provided with an undercut  35  (see  FIGS.  2  and  3   ). In this case, the undercut  35  forms an engagement element. 
     Attached to the suction connector  31  on the free end  33  thereof is an exemplary embodiment of a filter unit  37  according to the invention, which is illustrated in detail in  FIGS.  2  and  3   . 
     The filter unit  37  has a main body  39 , which, in the preferred exemplary embodiment shown here, is of cylindrical and sleeve-shaped construction and surrounds the upper part of the suction connector  31 , wherein the main body  39  extends between a first face end  41  and a second face end  43 . Furthermore, the main body  39  has an inlet opening  45  at the first face end  41 , wherein, in the region of the inlet opening  45 , provision is made of a neck  47  which projects into the inlet (suction) connector  31  such that the neck  47  extends substantially parallel to an outer wall  49  of the main body  39  that forms a tubular portion. The main body  39  furthermore has, in the region of the second face end  43 , an encircling flange  51  which extends away from the outer wall  49  in an outward direction and in which flange openings  53  are provided.  FIGS.  2  and  3    furthermore show that, in the region of the first face end  41 , provision is made at the inlet opening  45  of latching hooks  55  which, when the main body  39  has been mounted onto the suction connector  31 , engage with the undercut  35  such that pulling of the main body  39  off from the suction connector  31  is then prevented. 
     The filter unit  37  moreover has a cover  57  which is fastened to the main body  39  on that side of the first face end  41  which faces away from the suction connector  31 , wherein provision is made in the cover  57  of an entry opening  59 , which is of encircling form in this preferred exemplary embodiment, and the cover  57  is moreover configured in such a way that provision is made therein of a fluid channel  61  via which the entry opening  59  is connected to the inlet opening  45  in the main body  39 , so that a fluid such as air can enter the fluid channel  61  through the entry opening  59  and can then pass into the suction connector  31  through the inlet opening  45 . 
     The filter unit  37  furthermore has a locking body  63  which comprises a cylindrical portion  65  which is configured in such a way that it can be inserted into the inlet opening  45  and the neck  47  of the main body  39  in such a way that it prevents the latching hooks  55  from pivoting inward and, in this way, from being brought out of engagement with the undercut  35 . Consequently, the cylindrical portion  65  prevents the main body  39  from being able to be detached from the suction connector  31 . Moreover, a collar  67  is provided on the locking body  63 , said collar extending outward along the first face end  41  of the main body  39  and therebeyond. The locking body  63  is in this case clamped between the main body  39  or the first face end  41  thereof and the cover  57 . 
     The filter unit  37  moreover has a sleeve-shaped filter element  69  whose cylindrical portion  71 , which forms a circumferential surface, is formed from a sieve-like filter material and which also has a coupling portion  73  which is pushed over the cover  57 , wherein there is a press fit between the cover  57  and the coupling portion  73 , so that the filter element  69  cannot be readily pulled off from the cover  57 . The cylindrical portion  71  composed of the filter material extends as far as the encircling flange  51  on the main body  39 , wherein a ring  75  is provided on the cylindrical portion  71  on that end thereof which is remote from the coupling portion  73 , said ring engaging with the encircling flange  51 . 
     The filter unit  37  moreover has a substantially annular float body  77  which is arranged around the main body  39  and in particular the outer wall  49  of the latter, wherein the float body  77  is displaceable along the main body  39  or the outer wall  49  thereof between a closed position and an open position. If the float body  77  is in the closed position, it bears against the collar  67  of the locking body  63  and closes off the entry opening  59  in the cover  57 , while, in the open position, at the lower end, it bears against the encircling flange  51  of the main body  39  and closes off the flange openings  53  provided therein. The float body  77  thus moves within an annular space  79  formed between the filter element  69 ,  71  and the main body  39 . The float body  77  is in this case formed in such a way that, when the level in the dirty-water tank  5  rises, the float body  77  is displaced along the main body  39  toward the collar  67  of the locking body  63  and the entry opening  59  of the cover  57 . 
     Finally, in the preferred exemplary embodiment described here, an elastic ring element  81  is provided between the free end  33  of the suction connector  31  and the main body  39 , which elastic ring element is slightly compressed when the latching hooks  55  engage with the undercut  35 . In this way, damage to the filter unit  37  due to vibrations or detachment of said filter unit from the suction connector is prevented. Moreover, manufacturing tolerances are compensated by way of the elastic ring element  81 . Furthermore, the elastic ring element  81  can provide sealing action. 
     The exemplary embodiment of the filter unit  37  according to the invention can be fitted on the suction connector  31  of the scrubber dryer  1  in the following manner. Firstly, the elastic ring element  81  and the main body  39  are mounted onto the suction connector  31 , wherein the latching hooks  55  are brought into engagement with the undercut  35 . Then, the float body  77  is pushed onto the main body  39 , wherein the float body  77  surrounds the main body  39  or the outer wall  49  thereof. Then, the locking body  63  is inserted into the inlet opening  45  and locks the latching hooks  55  in the engagement position. The fitting of the locking body moreover ensures the correct engagement of the latching hooks. Due to the collar  67 , it is additionally achieved that the float body  77  can no longer be taken off. Subsequently, the cover  57  is fastened to the main body  39 , wherein the locking body  63  is thus clamped. Finally, the filter element  69  can be pushed over the arrangement fitted beforehand, wherein the press fit between cover  57  and coupling portion  73  prevents simple detachment of the filter element  69 . 
     During the operation of the scrubber dryer  1 , air laden with dirty water and dirt is sucked through the suction line  21  and the inlet connector  23  from the suction foot  19  into the dirty-water tank  5  by means of the suction turbine  25 , wherein the air passes through the cylindrical portion  71  of the filter element  69  and can then flow onward through the entry opening  59  and the inlet opening  45  to the suction turbine, wherein dirt particles are separated out at the cylindrical portion  71 . When the dirty-water level in the dirty-water tank  5  rises, the float body  77  moves from the position shown in  FIG.  5    further upward until, at a particular level, it is so close to the entry opening  59  of the cover  57  that, owing to the air flow, it is drawn against the collar  67  of the locking body  63  and closes off the entry opening  59 . In this case, the current consumption of the suction turbine is changed, and it is indicated to a user that the dirty-water level in the dirty-water tank  5  is so high that the tank has to be emptied. 
     The flange openings  53  in the encircling flange  51  of the main body  39  moreover make it possible for foam to be able to enter the annular space  79 , which likewise, even if the dirty-water level itself is still at a relatively low level, has the effect that the float body  77  is moved upward, so that likewise the entry opening  59  is closed off, whereby it is then indicated to the user that he or she has to empty the dirty-water tank  5 . 
     If the cylindrical portion  71  of the filter element  69  is sufficiently dirty, air can pass through said portion only to a small extent, which then leads to the float body  77  being drawn toward the entry opening  59 , and closing off the latter, owing to an air flow through the flange openings  53 . In this case, a user has to clean the filter element  69 , wherein he or she merely has to pull the coupling portion  73  off from the cover  57 . In this case, however, it is not possible for the float body  77  to be detached because it is still trapped between the encircling flange  51  and the collar  67 . 
     It is thus possible for the filter unit  37  to be fitted and also cleaned in a simple manner, wherein, when the filter unit  37  is cleaned and in particular when the filter element  69  is removed, there is no risk, in particular because of the locking body  63 , of the float body  77  being lost. Moreover, the construction of the filter unit  37  is very compact since the filter unit is arranged only around the suction connector  31  and thus takes up relatively little space in the dirty-water tank  5 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 
     
       
         
           
               
             
               
                   
               
               
                 Reference signs: 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1 
                 Scrubber dryer 
               
               
                 3 
                 Housing 
               
               
                 5 
                 Dirty-water tank 
               
               
                 7 
                 Cover element 
               
               
                 9 
                 Wheel 
               
               
                 11 
                 Floor surface 
               
               
                 13 
                 Brush head 
               
               
                 15 
                 Brush element 
               
               
                 17 
                 Fresh-water tank 
               
               
                 19 
                 Suction foot 
               
               
                 21 
                 Suction line 
               
               
                 23 
                 Inlet connector 
               
               
                 25 
                 Suction turbine 
               
               
                 27 
                 Drive motor 
               
               
                 29 
                 Fan wheel 
               
               
                 31 
                 Suction connector 
               
               
                 33 
                 Free end 
               
               
                 35 
                 Undercut 
               
               
                 37 
                 Filter unit 
               
               
                 39 
                 Main body 
               
               
                 41 
                 First face end 
               
               
                 43 
                 Second face end 
               
               
                 45 
                 Inlet opening 
               
               
                 47 
                 Neck 
               
               
                 49 
                 Outer wall 
               
               
                 51 
                 Encircling flange 
               
               
                 53 
                 Flange opening 
               
               
                 55 
                 Latching hook 
               
               
                 57 
                 Cover 
               
               
                 59 
                 Entry opening 
               
               
                 61 
                 Fluid channel 
               
               
                 63 
                 Locking body 
               
               
                 65 
                 Cylindrical portion 
               
               
                 67 
                 Collar 
               
               
                 69 
                 Filter element 
               
               
                 71 
                 Cylindrical portion 
               
               
                 73 
                 Coupling portion 
               
               
                 75 
                 Ring 
               
               
                 77 
                 Float body 
               
               
                 79 
                 Annular space 
               
               
                 81 
                 Elastic ring element