Abstract:
The invention relates to an orienting mechanism ( 20 ), with which, even in the case of unfavorable installation conditions at the container ( 10 ), a fill level measuring device ( 16 ) can be mounted on the container ( 10 ) and aimed, such that the line ( 17 ) of measurement is perpendicular to the surface ( 14 ) of a medium ( 13 ) to be sensed. The orienting mechanism ( 20 ) enables the pivoting of the measuring device ( 16 ) while yet providing a reliable sealing of the interior of the container.

Description:
FIELD OF THE INVENTION 
   The invention relates to an orienting mechanism for a fill level, or limit level, measuring device. 
   BACKGROUND OF THE INVENTION 
   Measuring devices for determining a fill level or limit level of a medium in a container are known in a multitude of different designs. Thus, for instance, there are fill level measuring devices available, which work contactlessly and are mounted at, on or in a lid of the container and above the maximum expected fill level of the medium in the container. Essentially from above, these contactless fill level measuring devices emit measuring signals internally in the container, directed toward the medium. The signals are reflected at the surface of the medium and led back to the measuring device. From the reflected signals, or their travel time, the distance between the surface of the medium and the measuring device can be determined, and, from there, the sought fill level of the medium is derived considering the geometry of the container. 
   Known limit level measuring devices are usually mounted at a predetermined location or height on a sidewall of the container, such that they protrude into the container and serve there as so-called limit level switches. When they are used, for example, for overfill protection and, accordingly, are mounted at the position of maximum allowable fill level in the container, they produce a switching signal, upon being covered by the medium. The switching signal turns off, or interrupts, further inflow of the medium into the container. When the limit switches are used, for example, for pump protection and, accordingly, are mounted in the container at the position of minimum fill level, which must not be subceeded, or fallen beneath, they produce a switching signal, when they are uncovered by the medium. The switching signal, in this case, prevents a further pumping, or outflow, of the medium out of the container. 
   A special problem occurs in the case of these measuring devices for determining a fill level or limit level when they are essentially mounted externally on the container and their sensors, or transducers, extend into the interior of the container. If the container shape is unfavorable, or the mounting position of the measuring device is unfavorable, it is currently not possible to position, or orient, the measuring device in a desired manner with reference to the measuring location or the required line of measurement. Apparatuses are known, with the help of which an above-described fill level measuring device can be oriented, but these apparatuses permit only a very limited adjustment of the inclination angle of the measuring device and/or they do not seal the interior of the container. 
   SUMMARY OF THE INVENTION 
   An object of the invention, therefore, is to provide an orienting mechanism for a fill level, or limit level, measuring device, which mechanism is sealed to pressure, while enabling the positioning and/or orienting of the measuring device as desired. 
   This object is achieved, according to the invention, by an orienting mechanism for a measuring device for determining fill level or limit level of a medium in a container, wherein the orienting mechanism includes a pivotable, ball-shaped, clampable member, which is attachable to the container, and which includes a sealing relative to the interior of the container. 
   In a preferred form of embodiment of the invention, the sealing is a purely metallic seal. 
   In another preferred form of embodiment of the invention, the sealing is an elastomeric seal, for instance an O-ring seal. 
   A further preferred form of the orienting mechanism of the invention relates to an ultrasonic fill level measuring device. 
   Yet another preferred form of embodiment of the orienting mechanism of the invention relates to a tuning-fork limit-level measuring device. 
   In another preferred form of embodiment of the invention, it is provided that the orienting mechanism includes a tube, which serves for cable routing. 
   In again other preferred embodiments of the orienting mechanism of the invention, the ball-shaped clampable member is arranged on the tube and/or the tube is arranged displaceably in the ball-shaped clampable member. 
   Yet again a further form of embodiment of the invention relates to an orienting mechanism, wherein at the end on the tube a connection apparatus is mounted for a drive and/or a sensor of the fill level measuring device. 
   Other preferred forms of embodiment of the orienting mechanism of the invention relate to a radar fill level measuring device, especially one in which a tube of the orienting mechanism serves as hollow conductor. 
   In still another preferred form of embodiment of the orienting mechanism of the invention, it is provided that the ball-shaped clampable member is clamped by a holding plate to a flange at or on the container. 
   Still other forms of embodiment of the invention concern the securement of the ball-shaped clampable member of the orienting mechanism to a cover plate closing a manhole of the container. In a special embodiment, the cover plate can be swung away from the container. 
   The invention will now be described and explained in greater detail on the basis of various examples of embodiments, with reference to the accompanying drawing, the figures of which show as follows: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described and explained in greater detail on the basis of various examples of embodiments, with reference to the accompanying drawing, the figures of which show as follows: 
       FIG. 1   a  schematic overall view of a fill level measuring device mounted on a first container and having an orienting mechanism of the invention; 
       FIG. 1   b  schematic overall view of a fill level measuring device mounted on a second container and having an orienting mechanism of the invention; 
       FIG. 2  schematic, perspective, side view of a microwave fill level measuring device having a first preferred form of embodiment of the orienting mechanism of the invention, with partially sectioned orienting mechanism and different antennas; 
       FIG. 3   a  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 2  and a parabolic antenna; 
       FIG. 3   b  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 2  and a rod antenna; 
       FIG. 3   c  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 2  and a horn antenna; 
       FIG. 3   d  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 2  and a planar antenna; 
       FIG. 4  schematic, perspective, side view of a fill level measuring device having a second form of embodiment of the orienting mechanism of the invention and other measuring means; 
       FIG. 5   a  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 3   a,  which is mounted on a cover of a manhole of a container; and 
       FIG. 5   b  perspective, side view of a microwave fill level measuring device having an orienting mechanism of  FIG. 5   a,  with the cover of the manhole in the open position. position. 
   

   For simplification, equal components or assemblies are provided with equal reference characters in the figures of the drawing. 
     FIGS. 1   a  and  1   b  provide a basic illustration of the use and advantages of the invention. Two different containers  1  and  10  are shown, on each of which a fill level measuring device  2  and  16 , respectively, is mounted. Both of these fill level measuring devices utilize, for example, the travel time method of measuring fill level. 
   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the case of the first container  1 , this example is a cylindrical container having a curved roof  3 . In container  1  is a first medium  4 , which, as illustrated here, can be a liquid, the level of which is being measured by a first fill level measuring device  2  shown in this case to be a free radiating device. The liquid medium  4  has in the container  1  a horizontal surface  5 , on which the measuring signals sent from the fill level measuring device  2  to the medium  4  are reflected. The reflected signals are received by the fill level measuring device  2  and serve for determining the distance between fill level measuring device  2  and surface  5 , from which, knowing the inside geometry of the container  1 , the sought fill level of the medium  4  in the container  1  is determined. 
   A path of the signals from the measuring device  2  to the medium  4  and back is indicated in  FIG. 1   a  by a dashed line, which represents the line  6  of measurement. In the case of this type of container with a curved roof  3 , as shown in  FIG. 1   a , it frequently happens that openings already present in the roof  3 , for instance manholes  8 , or nozzles, are used for installing a fill level measuring device  2 . If the manhole  8 , or the nozzle, is closed by an inclined cover  7 , then the fill level measuring device  2  is usually secured thereon. 
   Because of the desired accuracy of the measurement, it is important in the case of media  4  with a smooth surface  5  that the signals impinge perpendicularly on the surface  5 . In order to assure this, the fill level measuring device  2  can be oriented on an inclined cover  7  of a manhole  8  in the curved roof  3  of the container  1  by means of the orienting mechanism  20  of the invention such that the line  6  of measurement is normal to the surface  5  of the medium  4 , as shown in  FIG. 1   a.    
   In the case of the example of a second container  10  illustrated in  FIG. 1   b , such is a container  10  with a flat roof  11  and a conical lower portion  12 . Containers  10  of this type are frequently used, as is, in fact, shown in  FIG. 1   b , to store a pourable-solids, second medium  13 , a so-called bulk goods, such as, for example, sand or cement. In the case of a medium such as one of these, the upper surface is usually not horizontal. 
   A second fill level measuring device  16  is secured on the flat roof  11 , on a nozzle  15  located there. The second fill level measuring device  16  is, like the first fill level measuring device  2  of  FIG. 1   a , again illustrated as a free radiating measuring device operating on the basis of the travel time method, by way of which the sought fill level of the second medium  13  can be determined, similarly to the situation with the first fill level measuring device  2 . The bulk goods medium  13  does not form a horizontal upper surface in the container, but, instead, an upper surface  14  in the form of a pour cone. 
   A dashed line  17  illustrates the path of the measuring signals to the pour cone and thus the line of measurement. In the case of such pour cones, it is recommended that the line of measurement be the shortest distance from the fill level measuring device  16  to the medium  13 . This is usually the case, when the line of measurement is perpendicular to a flank of the pour cone. In order to assure this, the fill level measuring device  16  can be aimed by means of the orienting mechanism  20  of the invention, as already introduced in the context of  FIG. 1   a , such that the line of measurement is normal to the upper surface  14  of the medium  13 , as shown in  FIG. 1   b . The signals reflected on the surface  14  of the medium  13  are received by the fill level measuring device  16  and serve for determining the distance between the fill level measuring device  16  and the surface  14 . With knowledge of the geometric conditions in the interior of the container  10  and the pour cone typically formed by the medium  13 , the sought fill level is then determined. 
   For better understanding the orienting mechanism  20 ,  FIG. 2  shows a microwave fill level measuring device  40  with a first preferred form of embodiment of the orienting mechanism  20 . Two different antennas are indicated for the microwave fill level measuring device  40 . The microwave fill level measuring device  40  includes an electronics housing  41  with a connector part  42  and an antenna  43  for radiating and receiving the measuring signals. 
   The orienting mechanism  20  includes a connecting piece  21 , which is connected with the connector part  42  of the fill level measuring device  40 . On the connecting piece  21  of the orienting mechanism  20  is appended a pivotable, ball-shaped, clampable member  23 , which sits in a hollow of a flange  35 , the hollow being formed as a ball-seat  22 . The ball-seat  22  is preferably a bore passing completely through the flange; the edge of the bore is beveled. One possible embodiment of such a ball seat  22  is shown in  FIG. 2  in partial cross section. A holding plate  26 , likewise provided with a ball seat, sits on the pivotable, ball-shaped, clampable member  23  and is tightened by means of screws, of which only a single screw  27  is shown here, such that the pivotable, ball-shaped, clampable member  23  of the orienting mechanism  20  is held in the ball seat  22 . 
   The connection piece  21  and the pivotable, ball-shaped, clampable member  23  have a bore passing through them, into which a tube  24  is inserted. In the case illustrated in  FIG. 2  of a microwave fill level measuring device  40 , the tube  24  is the round, hollow conductor for the microwave signals and connects the electronics in the electronics housing  41  with the antenna  43 . By way of example,  FIG. 2  shows, as antenna variants, a parabolic antenna  43   a  and a planar antenna  43   b , which are each connectable with the hollow conductor tube  24 . In  FIG. 2 , a cavity is indicated extending from the connection piece  21  into that part of the pivotable, ball-shaped, clampable member  23  facing the electronics housing  41 . Inserted in this cavity is a helical spring  25 , which encircles the tube  24  and biases the ball-shaped, clampable member  23  towards the electronics housing  41 . 
   In the case of the illustrated, special form of embodiment of the invention, a seat for a sealing ring is provided in the ball seat  22 . Placed in this seat is a seal  28 , for example an elastomeric seal, preferably an O-ring. This seal  28  effects a sealing of the interior of the container relative to the atmosphere. Such a seal is especially advantageous, when the flange  35  is a welded flange, which is welded into the roof of the container. Other types of sealing are possible. Thus, for instance, a purely metallic seal can be used. 
   Loosening of the screws  27  enables the orienting mechanism (or, more accurately, its ball-shaped, clampable member  23 ) to pivot in the ball seat  22 , so that the antenna  43  of the fill level measuring device  40  can be aimed in the desired direction. 
   To illustrate possible configurations of the microwave fill level measuring device  40  with the orienting mechanism  20  of the invention,  FIGS. 3   a ,  3   b ,  3   c  and  3   d  show as perspective, overall views, a microwave fill level measuring device  40  in each case with another antenna  43 . Thus,  FIG. 3   a  shows the microwave fill level measuring device  40  with a parabolic antenna  43   a . Clearly recognizable is the securement of the ball-shaped, clampable member  23  of the orienting mechanism  20  by means of the holding plate  23  to the flange  35 . Clearly recognizable also is the tube  24 , which is serving as the hollow conductor. 
     FIG. 3   b  again shows the microwave fill level measuring device  40 , this time with a rod antenna  43   c , which, in this embodiment, is appended directly beneath the flange  35 .  FIGS. 3   c  and  3   d  are further embodiments of the microwave fill level measuring device  40  and the orienting mechanism  20 . The differences lie in the particular antennas, horn antenna  43   d  in  FIG. 3   c  and planar antenna  43   b  in  FIG. 3   d , and the forms of embodiment of the orienting mechanism  20  resulting therefrom. 
     FIG. 4  shows special embodiment of devices equipped with the orienting mechanism  20  of the invention. The orienting mechanism  20  is mounted to an electronics housing  50  in the manner described above. In turn, its ball-shaped, clampable member  23  is held on the flange  35  by the holding plate  26 . As desired, connectable to the orienting mechanism  20  is a limit level detector  51 , for example a limit level switch based on the tuning-fork principle, or an ultrasonic transmitter  52  continuously measuring the fill level and forming together with the accompanying electronics in the electronics housing  50  an ultrasonic fill level measuring device. 
   In the case of the limit level detector  51 , the tube  24  seated in the ball-shaped, clampable member  23  of the orienting mechanism  20  (see, in this connection, also  FIG. 2 ) serves to accommodate a drive and/or a sensor in the vicinity of the tuning forks  53  and as a cable conduit for the electrical connection of the drive and/or sensor with the electronics in the electronics housing  50 . In the case of the ultrasonic fill level measuring device  52 , the tube  24  serves as a cable conduit for the electrical connection cable to the accompanying electronics in the electronics housing  50 . It is possible in simple manner to seat the tube  24  longitudinally displaceably in the ball-shaped, clampable member and to provide a suitable securement for the tube  24 . It is, furthermore, possible to provide a seal between the tube  24  and the ball-shaped, clampable member. In this way, with suitable length of the tube  24 , it also becomes possible with the orienting mechanism  20  of the invention not only to pivot the antenna, sensors or detectors connected thereto into a desired position with respect to the vertical or with respect to the roof of the container, but also to adjust the “depth of penetration” and the protruding of the antennas or sensors into the container. 
   To illustrate other possibilities for applying the orienting mechanism  20 ,  FIGS. 5   a  and  5   b  show the microwave fill level measuring device  40  with parabolic antenna  43   a  (see, in this connection, also  FIG. 3   a ) and with the orienting mechanism  20  mounted on a swingable cover plate  54  of a manhole  55  in the roof region of a container (see, in this connection, also  FIGS. 1   a  and  1   b ). The microwave fill level measuring device  40 , which is connected with the ball-shaped, clampable member  23 , is secured by the holding plate  26 , which clamps the clampable member  23  against the flange  35  (see, in this connection, also  FIG. 2 ), and by means of flange  35  to the cover plate  54 . On the basis of suitable length of the tube  24  and its ability to shift in the ball-shaped, clampable member  23 , the extension of the tube  24  and the parabolic antenna  43   a  secured thereon into the manhole  55  and the container can be adjusted such that, in the case of opening of the cover plate  54 , as shown in  FIG. 5   b , the microwave fill level measuring device  40 , including its antenna, can be swung out of the manhole  55 . For maintenance work on the antenna, for example for the removal of accretions, etc., such is a great advantage. Moreover, by pivoting of the ball-shaped, clampable member  23  of the orienting mechanism  20 , the antenna can be aimed in the desired manner onto the surface of the medium in the container (see, in this connection, also  FIG. 1   a ), so that also manhole covers arranged other than horizontally can be utilized.