• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to an electromagnetically compensating beam balance, comprising a two-armed beam arrangement (12, 14, 20) rotatably mounted on a base, each lever arm of which carries a load receptacle (18a) assigned to it, a first of the load receptacles (18a, b) is restricted by means of a parallel link arrangement to movements while maintaining a vertical alignment, and a compensation unit (26) coupled to the beam arrangement (12, 14, 20), comprising an electromagnetic plunger coil (261) movable with the beam arrangement (12, 14, 20) in the magnetic field of a permanent magnet (262) fixed to the base. The invention is characterized in that the bar arrangement has an upper bar (12) and a lower bar (14) of equal length, which are arranged parallel to it and which are each centered around one of two vertically superposed, mutually parallel and perpendicular axes of rotation ( 121, 141) are rotatably mounted and their bar ends lying vertically one above the other in pairs each have a joint (122a, b; 142a, b) with an associated, vertically extending, rigid coupling piece (16a, b) which supports the respectively associated load bearing (18a , b) carries, are coupled.
    公开号:CH712349B1
    申请号:CH00471/17
    申请日:2017-04-07
    公开日:2021-02-26
    发明作者:Dr Thomas Fröhlich Prof；Falko Hilbrunner Dr；Fehling Thomas；Ilko Rahneberg Dr
    申请人:Sartorius Lab Instr Gmbh & Co Kg；
    IPC主号:
    专利说明:

    Field of the invention
    The invention relates to an electromagnetically compensating beam balance, comprisinga two-armed beam arrangement rotatably mounted on a base, each lever arm of which carries a load receptacle assigned to it, a first of the load receptacles being restricted to movements while maintaining a vertical orientation by means of a parallel link arrangement, anda compensation unit coupled to the bar arrangement, comprising an electromagnetic plunger coil movable with the bar arrangement in the magnetic field of a permanent magnet fixed to the base.
    The invention further relates to a method for calibrating such a scale and a method for determining a test weight by means of such a beam scale.
    State of the art
    Scales whose balance bars are guided in parallel have long been known from the prior art. Examples of this can be found in DE 441 483 A and US Pat. No. 2,170,798 A.
    DE 23 65 460 A1 shows an electromagnetically force-compensated beam balance with two load ranges implemented via the lever ratio of the balance beam and additional compensation coils.
    A generic beam balance is also known from DE 26 21 483 C2.
    Beam balances are used in particular in the field of precision comparators, i.e. in the field of precision balances for the direct comparison of two weights with one another. Such a beam balance with a simple weighing beam which is suspended from a stationary base via a swivel joint is known from the aforementioned document. The simple weighing beam is asymmetrical, i.e. with beam arms of different lengths. On the longer beam arm, a top-shell load pick-up is provided for the fixed mounting of a counterweight. A sub-shell load suspension is attached to the shorter beam arm via another joint. This is connected to an electromagnetic compensation unit. A compensation unit is generally understood here to mean an arrangement comprising an electromagnetic plunger coil and a permanent magnet fixed to the base. Such a compensation unit represents the core of every electromagnetically compensating balance. The plunger coil, which is connected to the load pick-up in a fixed manner or via a lever system, is arranged immersed in the magnetic field of the permanent magnet. The moving coil can be energized with a compensation current which is regulated by a control unit in such a way that any deflection of the moving coil, in particular those caused by the application of force to the assigned load, is counteracted by a corresponding magnetic field, so that the balance as a whole remains in its "zero position" . The compensation current required for this compensation is a direct measure of the deflecting force. The proportionality factor between the compensation current and the deflecting force can be determined, for example, by calibrating the balance with known test weights.
    Since the beam ends of a simple weighing beam pivotable about an axis of rotation describe a part-circular movement, a moving coil fixedly connected to the beam end would also describe a correspondingly curved movement. To prevent this, the plunger coil of the known device is not connected to the end of the beam itself, but to the load pick-up connected to it in an articulated manner, a parallel link arrangement additionally being provided which forces the load pick-up and the plunger coil into linear movement. For this purpose, two arms arranged vertically one above the other are coupled to the base via joints and extend parallel to one another. At their free ends, the links each have a further joint, via which they are connected to a rigid coupling piece, which in turn is rigidly connected to the plunger coil. The disadvantage of the known device is that the joints on the weighing beam, in particular its pivot joint, are exposed to high forces when weighing large weights and therefore have to be made correspondingly strong, which can be detrimental to the measurement precision.
    In the course of general efforts to reduce mechanical standard sizes to electromagnetic sizes, the principle of the so-called watt balance has been developed. The Watt balance is basically a conventional, electromagnetically compensating balance with an additional deflection unit, which is basically constructed like one of the compensation units described above and is coupled to the load bearing of the balance. It is known that the compensation force that is generated by means of one of the compensation units described above is proportional to the compensation current. The factor BI is included in the corresponding proportionality factor, i.e. the product of the magnetic field of the permanent magnet and the length of the coil immersed in it. Both quantities cannot be measured directly with the accuracy required for precision weighing. However, it is known to the person skilled in the art that the factor BI can also be calculated using the voltage which induces a changing magnetic field in the coil. In particular, the factor BI is equal to the quotient of the induced voltage and the speed at which the moving coil moves in the field of the permanent magnet.
    In the aforementioned Watt balances, the deflection unit is therefore used to set the weighing system and in particular the plunger coil of the compensation unit in a periodic oscillation, the speed of which can be precisely determined, for example by means of an interferometer. If the voltage induced in the plunger coil is measured precisely at the same time, the quotient of the induced voltage and plunger coil speed can be calculated for each point in time, which theoretically should be the same for all points in time, namely in particular corresponds to the factor BI.
    Task
    It is the object of the present invention to provide a high-precision comparator and a method for its calibration and a method for its operation.
    Statement of the invention
    The object is initially achieved in conjunction with the features of the preamble of claim 1 in that the bar arrangement has an upper bar and a parallel to this, the same length lower bar, each centered around one of two vertically superimposed, parallel to each other and axes of rotation aligned perpendicular to the beam extension are rotatably mounted and their beam ends lying vertically one above the other in pairs are coupled via a joint with an associated, vertically extending, rigid coupling piece which carries the respectively assigned load pick-up.
    Preferred embodiments of the invention are the subject of the dependent claims.
    The basic idea of the invention is to modify the asymmetrical parallel link arrangement, especially the compensation arrangement for a linear movement, into a symmetrical parallel link arrangement in which the weighing beams themselves act as parallel links. As a result, both load pickups are forced to perform purely linear, vertically aligned movements in a symmetrical manner. The upper and lower beams, together with the two coupling pieces, thus form a parallelogram that is symmetrical in the "zero position", the coupling pieces of which are coupled to the ends of the beams via the joints and are always aligned exactly vertically, regardless of the pivot position of the two beams.
    Particularly in the case of high weights that are to be compared with one another, a high weight is exerted on said joints. In a further development of the invention, provision is therefore made for a third bar parallel to the upper and lower bar to be rotatably mounted in the center around a third axis of rotation located vertically between and parallel to the axes of rotation and for each of its bar ends to be articulated to the associated coupling piece is. This coupling is preferably carried out in each case by means of a vertically extending coupling band which is coupled by means of two joints. In other words, a measuring beam, which can also be referred to as an intermediate lever, is installed between the upper and lower beams. A compensation unit can particularly preferably act on this. In any case, however, the intermediate lever significantly reduces the forces acting on the joints of the parallelogram.
    The plunger coil of the compensation unit is advantageously arranged on a vertically extending boom which is fixed centrally on one of the beams, particularly preferably on the aforementioned third beam. When the bar arrangement is pivoted, it thus executes a part-circular movement, the tangent of which lies exactly horizontally in the “zero position”. As explained above, the principle of electromagnetic compensation consists in compensating for any deflection as immediately as possible, so that a quasi path-free measurement is possible. The theoretical part-circular movement of the moving coil is thus practically reduced to a minimal, almost purely linear movement.
    To regulate the compensation, it is necessary to determine the exact position of the bar system, in particular the “zero position” detection. For this purpose, it is preferably provided that each of the two coupling pieces is symmetrically connected to a structurally identical position sensor. The person skilled in the art will recognize that the position determination would also be possible with only one position sensor. However, since the system described here is primarily based on the symmetry of the overall arrangement, the symmetrical arrangement of two structurally identical position sensors is considered to be particularly favorable. Their signals, which may be slightly different in practice, can be offset against one another, for example averaged, in order to improve the measurement accuracy. As an alternative to the arrangement of the position sensors on the coupling pieces, it can also be provided, particularly preferably, that the third bar is symmetrically connected to a structurally identical position sensor on both sides of its axis of rotation. This means that all of the electronics are relocated to the central area of the balance, which enables a more compact design.
    In a particular development of the invention it is provided that one of the coupling pieces is coupled to an additional compensation unit, comprising a rigidly connected to it, first additional electromagnetic moving coil in the magnetic field of an additional permanent magnet fixed to the base. With regard to the symmetry of the overall arrangement, which is considered particularly favorable here, it is preferably even provided that the other of the coupling pieces is also coupled to an additional compensation unit, comprising an additional electromagnetic moving coil rigidly connected to it in the magnetic field of an additional permanent magnet fixed to the base . By providing one or more additional compensation units, the beam balance according to the invention can be used as a watt balance. The central compensation unit mentioned above can be used as a deflection unit. The additional compensation unit or the additional compensation units then take on the actual compensation task. It is therefore important to measure your factor BI precisely. This can be done by measuring the voltages induced in their moving coils as a function of their moving coil speeds with periodic deflection by the central compensation unit functioning as a deflection unit.
    In order to make the measurement of the moving coil speed particularly precise, it is provided in a particularly preferred embodiment of the invention that at least one additional moving coil is rigidly connected to a reflector of a measuring arm of an interferometer having at least one measuring arm and a reference arm, the reference arm of which is a Has base-fixed reflector. With regard to the preferred symmetrical configuration of the overall arrangement, in the case of two additional moving coils, it is preferably provided that the interferometer has two measuring arms - whose reflectors are each assigned to one of the additional moving coils - and a common reference arm with a base-fixed reflector. Such a three-armed interferometer allows differential measurements between the different measuring arms as well as measurements between each measuring arm and the common reference arm. Such measurements can be appropriately offset against one another in order to reduce measurement errors.
    A preferred method for calibrating a beam balance according to the invention with one or two additional plunger coils and a two- or three-armed interferometer provides the following steps:Periodic energization of the moving coil to generate a correspondingly periodic movement of each additional moving coil,Measuring the induced voltage in each additional moving coil as well as its speed measured by means of the interferometer,Calculate the resulting voltage / speed quotient as a calibration factor andStoring the respectively calculated calibration factor in a memory unit of a control device of the beam balance as a proportionality factor between a vertical differential force acting between the load receptacles and the respective compensation current through each additional moving coil required to compensate it.
    In other words, the calibration principle known in principle from Watt balances is applied in a particularly advantageous manner to the beam balance according to the invention. It is of course also possible to use one or both of the additional compensation units as a deflection unit for determining the calibration factor of the central compensation unit. In order to use the methods explained below for determining a test weight, however, it is necessary to know the calibration factors of the additional compensation units.
    When using a beam balance according to the invention with only one additional compensation unit, the method for determining a test weight comprises the following steps:Loading the first load with a substitute weight that is less than the test weight,Energizing the additional moving coil with a first partial compensation current,Determining the absolute amount of the first partial compensation current required to compensate for the vertical differential force applied between the load receptacles,Loading the second load bearing with the test weight,Energizing the additional moving coil with a second partial compensation current,Determining the absolute amount of the second partial compensation current required to compensate for the vertical differential force applied between the load receptacles,Determining a total compensation current representative of the test weight as the sum of the absolute amounts of the partial compensation currents.
    In other words, two measurement runs are carried out. Initially, only a substitute weight is placed on one of the load receptacles. The result is a vertically directed differential force between the two load receptors, which should cause the beam arrangement to deflect from its "zero position". However, the plunger coil of the additional compensation unit is energized at the same time so that the deflection is compensated and the bar arrangement remains in its "zero position". Depending on whether the (only) additional compensation unit is coupled to the coupling piece of the first load pick-up (with substitution weight) or the coupling piece of the second load pick-up (empty), a positive or negative compensation current is required. Its absolute value is a measure of the differential force to be compensated.
    Another measurement is then carried out, the test weight being placed on the second load bearing (the substitution weight remaining on the first load bearing). This again results in a vertically directed differential force which has to be compensated by the additional compensation unit. For this purpose, a second partial compensation current is required, which in any case has the opposite sign of the first partial compensation current. Its absolute value depends on the mass ratio of test weight to substitution weight.
    Finally, the partial compensation currents determined in the two steps can be added up in terms of amount, which leads to a total compensation current that is representative of the weight of the test weight. The main advantage of this method is that it is possible to work with comparatively low partial compensation currents, since the additional compensation unit is never loaded with the full test weight, but only with the lower substitution weight or the difference between test weight and substitution weight. This results in a reduced heating of the plunger coil during the weighing process, which improves the accuracy of the weighing.
    The substitution weight particularly preferably corresponds to approximately half the test weight. However, neither an exact match nor a precise knowledge of the substitution weight is required. The person skilled in the art will recognize that with a weight ratio of about 1: 2 of substitution weight to test weight, the differential forces in both measurement steps (apart from the sign) are approximately the same and therefore approximately the same partial compensation currents (apart from the sign) are required. Both measurement processes are therefore carried out under almost the same conditions with regard to the associated heat development.
    This also represents a particularly favorable situation with regard to the calibration of the beam balance according to the invention. Thus, in a preferred development of the measurement method explained above, it is provided that the substitution weight has approximately half the nominal mass of the test weight and the beam balance is by means of the above Calibration method is calibrated, the additional moving coil being energized with a calibration current, the current strength of which is such that it would be suitable as a compensation current to compensate for a vertical differential force between the load receptacles, which is equal to half of the weight force corresponding to the nominal mass of the test weight. In other words, the calibration method for determining the factor BI of the additional moving coil is carried out when the auxiliary moving coil is energized, the calibration current roughly corresponding to the partial compensation currents required in the subsequent measurements. Due to the special choice of the substitution weight in relation to the nominal mass of the test weight, as already explained above, these are roughly the same as one another and are also easily predictable. The calibration can therefore take place very precisely at that operating point at which the subsequent measurements also take place. Problems with non-linearities that frequently occur in practice are thus avoided. The person skilled in the art will, however, recognize that the asymmetrical energization of a (single) additional moving coil with the calibration current leads to an undesired deflection during the calibration process. It is therefore understood that this deflection must in turn be compensated for. This can be done, for example, by applying the substitution weight, by appropriately energizing the central plunger coil or by energizing an additional plunger coil that may be provided but not used in the measurements explained above.
    A method with the following steps is even more favorable, because it is associated with a further reduction in the required partial compensation currents:Loading the first load with a substitute weight that is less than the test weight,Energizing the additional moving coils with a first partial compensation current each of the same amount and opposite sign,Determination of the absolute amounts of the first partial compensation currents required to compensate for the vertical differential force applied between the load receptacles,Loading the second load bearing with the test weight,Energizing the additional moving coils with a second partial compensation current each of the same amount and opposite sign,Determination of the absolute amounts of the second partial compensation currents required to compensate for the vertical differential force applied between the load receptacles,Determining a total compensation current representative of the test weight as the sum of the absolute amounts of all partial compensation currents.
    In contrast to the aforementioned method, two additional plunger coils are always involved in each measurement. They are complementary, i.e. energized with different signs but the same absolute value. In the particularly preferred case that the substitution weight here also has approximately half the nominal mass of the test weight, each additional compensation unit only has to compensate for a quarter of the test weight in each measurement process. The required current strength of the partial compensation currents is correspondingly halved compared to the previously explained method.
    When calibrating the beam balance according to the invention, i.e. when determining the factors BI of each of the two additional compensation units, a lower calibration current can be used, namely in particular a calibration current that is halved compared to the calibration method explained above.
    Further features and advantages of the invention emerge from the following specific description and the drawings.
    Brief description of the drawings
    The figures show: FIG. 1: a schematic illustration of a beam balance according to the invention in a preferred embodiment; FIG. 2: a schematic illustration of a beam balance according to the invention in a simplified embodiment
    Detailed description of preferred embodiments
    The same reference symbols in the figures indicate the same or analogous elements.
    Figure 1 shows a highly schematic representation of a preferred embodiment of a beam balance 10 according to the invention. The beam arrangement of the beam balance 10 comprises an upper beam 12, which is rotatably mounted around a fixed axis of rotation 121, which is oriented perpendicular to its beam extension and horizontally. At its two beam ends, i.e. at the free end of its equally long beam arms, the upper beam 12 carries joints 122a, b, the meaning of which will be discussed in more detail below.
    Parallel to the upper beam 12, a lower beam 14 is arranged, which is rotatably mounted about a fixed axis of rotation 141, which is arranged vertically below the upper beam axis of rotation 121 and is oriented parallel to this. The lower beam 14 carries joints 142a, b at its two beam ends, i.e. at the free ends of its beam arms of equal length. These lower beam joints 142a, b are connected to the respectively assigned upper beam joints 122a, b via a rigid coupling piece 16a, b. The result is a pivotable bar parallelogram, the sides of which, implemented by the coupling pieces 16a, b, are always aligned vertically. Associated load receptacles 18a, 18b are rigidly connected to the coupling pieces 16a, 16b and, in the embodiment shown, are designed as upper-shell load receptacles. The person skilled in the art will understand that sub-shell variants can also be implemented within the scope of the present invention.
    In the embodiment shown in Figure 1, the bar arrangement also includes a third bar, referred to here as measuring bar 20, which is arranged in parallel alignment between the upper bar 12 and the lower bar 14 and rotatable about a fixed axis of rotation 201, which extends vertically between the upper - and lower beam axes of rotation 121, 141 are arranged and aligned parallel to these, is mounted. The measuring beam 20 is coupled to the respectively assigned coupling piece 16a, b via a vertically arranged coupling belt 22a, b. This takes place via coupling belt joints 221a, b arranged vertically one above the other in pairs. This arrangement clearly relieves the load on the beam joints 122a, b.
    In the area of the measuring beam axis of rotation 201, a vertically aligned arm 24 is rigidly connected to the measuring beam 20. A central compensation unit 26 is provided at the free end of the boom 24. This comprises an electromagnetic plunger coil 261 which is rigidly fixed to the free end of the boom 24. The moving coil 261 lies in the field of a permanent magnet 262 fixed to the housing. Current to the moving coil 261 leads, depending on the sign and current strength, to a torque acting on the measuring beam 20. Conversely, an asymmetrical loading of the load receptacles 18a, b leads to a pivoting of the measuring beam 20 and thus to an essentially horizontal deflection of the moving coil 261 The compensation current required for this is a measure of the vertical differential force between the two load receptacles 18a, b. In order to be able to detect the achievement of the complete compensation, i.e. the holding of the bar arrangement in the "zero position", the measuring bar 20 is provided with two structurally identical position sensors 28a, b arranged symmetrically on both sides of its axis of rotation 201. Their signal is used to regulate the compensation current.
    To this extent, a particularly preferred embodiment of a symmetrical, electromagnetically compensating beam balance has been described.
    The embodiment shown in Figure 1 is expanded to include two additional compensation units 30a, b, which are not absolutely necessary. Their plunger coils 301a, b are rigidly connected to the respectively assigned coupling piece 16a, b. The associated permanent magnets 302a, b are arranged fixed to the base. For high-precision position determination or for high-precision determination of the speed of movement of the plunger coils 301a, b, an interferometer is provided which has a reference arm and two measuring arms. The reflector 321 of the reflector arm is arranged centrally and fixed to the housing. The reflectors 322a, b are rigidly connected in a symmetrical manner to one of the plunger coils 301a, b.
    In a preferred calibration method, the central compensation unit 26 is used as a deflection unit, its moving coil 261 being energized with a periodic current. This leads to a periodic deflection of the beam arrangement. The deflection preferably takes place at a frequency in the resonance range of the overall arrangement. The periodic deflection of the bar arrangement leads via the coupling pieces 16a, b to a periodic deflection of the additional plunger coils 301a, b, which leads to an induced voltage in the plunger coils 301a, b. The induced voltage is proportional to the speed of movement by the calibration factor B1, i.e. the product of the immersed coil length and the magnetic field of the respectively assigned permanent magnet 302a, b. The speed of movement can be determined with high precision using the interferometer described above.
    If the calibration factor of each of the additional compensation units 30a, b is known in this way, vertical differential forces between the load receptacles 18a, b without mechanically connected calibration can be obtained directly from the compensation currents in the additional compensation units 30a, b required to compensate for this differential force determine. The central compensation unit 26 no longer plays a role in these measurements.
    With regard to particularly preferred embodiments of the calibration and measuring method, which aims in particular to calibrate the beam balance at the operating point of the subsequent measurement and to measure with minimized compensation currents, reference is made to the corresponding explanations in the general part of the description.
    FIG. 2 shows an embodiment of a beam balance 10 'according to the invention, which in principle has the same function, but is significantly simplified. In the case of the beam balance 10 ', the measuring beam 20 and the coupling belts 22a, b have been dispensed with. In this embodiment, the boom 24 is fixed directly to the upper beam 12, preferably exactly in the middle. In this embodiment, the position sensors 28a, b are arranged directly on the coupling pieces 16a, b. For the rest, reference can be made to the above explanation of FIG.
    Of course, the embodiments discussed in the specific description and shown in the figures are only illustrative embodiments of the present invention. In the light of the disclosure here, a person skilled in the art is provided with a wide range of possible variations.
    List of reference symbols
    10, 10 'beam balance 12 upper beam 121 rotation axis of 12 122a, b joints of 12 14 lower beam 141 rotation axis of 14 142a, b joints of 14 16a, b coupling piece 18a, b load bearing 20 measuring beam 201 rotation axis of 20 22a, b coupling belt 221a, b joint of 22a, b 24 boom 26 central compensation unit 261 plunger coil of 26 262 permanent magnet of 26 28a, b position sensor 30a, b additional compensation unit 301a, b plunger coil of 30a, b 302a, b permanent magnet of 30a, b 321 reference arm Reflector 322a, b measuring arm reflector
    权利要求:
    Claims (14)
    [1]
    1. Electromagnetically compensating beam balance, comprising- A two-armed beam arrangement (12, 14, 20) rotatably mounted on a base, each lever arm of which bears a load receptacle (18a, b) assigned to it, a first of the load receptacles (18a) on movements by means of a parallel link arrangement while maintaining a vertical orientation is restricted, and- A compensation unit (26) coupled to the bar arrangement (12, 14, 20), comprising an electromagnetic plunger coil (261) movable with the bar arrangement (12, 14, 20) in the magnetic field of a permanent magnet (262) fixed to the base,characterized,that the bar arrangement has an upper bar (12) and a lower bar (14) of the same length, which are arranged parallel to this and which are each rotatably mounted in the middle about one of two axes of rotation (121, 141) which are vertically superimposed, parallel to each other and perpendicular to the bar extension and the beam ends of which are vertically superposed in pairs via a joint (122a, b; 142a, b) with an associated, vertically extending, rigid coupling piece (16a, b) which carries the respectively associated load receptacle (18a, b) .
    [2]
    2. beam balance according to claim 1,characterized,that a third bar (20) parallel to the upper and lower bar (12, 14) is rotatably mounted in the middle about a third axis of rotation (201) lying vertically between and parallel to their axes of rotation (121, 141) and each of its bar ends is articulated to the respectively assigned coupling piece (16a, b).
    [3]
    3. beam balance according to claim 2,characterized,that each end of the beam is coupled to its associated coupling piece (16a, b) via a vertically extending coupling band (22a, b) coupled by means of two joints (221a, b).
    [4]
    4. Beam balance according to one of the preceding claims,characterized,that the plunger coil (261) is arranged on a vertically extending arm (24) fixed centrally on one of the beams (12, 14, 20).
    [5]
    5. Beam balance according to one of the preceding claims,characterized,that each of the two coupling pieces (16a, b) is connected to a structurally identical position sensor (28a, b), the two position sensors (28a, b) being arranged symmetrically with respect to a plane spanned by the axes of rotation (121, 141).
    [6]
    6. beam balance according to one of claims 2 to 4,characterized,that the third bar (20) is connected on both sides of its axis of rotation (201) to a structurally identical position sensor (28a, b), the two position sensors (28a, b) being symmetrical with respect to a plane spanned by the axes of rotation (121, 141, 201) are arranged.
    [7]
    7. Beam balance according to one of the preceding claims,characterized,that one of the coupling pieces (16a, b) with an additional compensation unit (30a, b), comprising a first additional electromagnetic plunger coil (301a, b) rigidly connected to it in the magnetic field of an additional permanent magnet (302a, b) fixed to the base , is coupled.
    [8]
    8. Beam balance according to claim 7characterized,that the other of the coupling pieces (16a, b) also with an additional compensation unit (30a, b), comprising an additional electromagnetic plunger coil (301a, b) rigidly connected to it in the magnetic field of an additional permanent magnet (302a, b) fixed to the base ) is coupled.
    [9]
    9. beam balance according to one of claims 7 to 8,characterized,that at least one additional plunger coil (301a, b) is rigidly connected to a reflector (322a) of a measuring arm of an interferometer having at least one measuring arm and a reference arm, the reference arm of which has a reflector (321) fixed to the base.
    [10]
    10. A method for calibrating a beam balance (10) according to claim 9,comprehensive the steps:- Periodic energization of the plunger coil (261) to generate a corresponding periodic movement of each additional plunger coil (301a, b),- measuring the induced voltage in each additional moving coil (301a, b) as well as its speed measured by means of the interferometer,- Calculate the resulting voltage / speed quotient as a calibration factor and- Storing the respectively calculated calibration factor in a memory unit of a control device of the beam balance (10) as a proportionality factor between a vertical differential force acting between the load receptacles (18a, b) and the respective compensation current through each additional moving coil (301a, b) required to compensate it ).
    [11]
    11. A method for determining a test weight by means of a beam balance (10) according to claim 9, insofar as it relates to claim 7,comprehensive the steps:- loading the first load receptacle (18a) with a substitute weight that is less than the test weight,- energizing the additional moving coil (301a, b) with a first partial compensation current,- Determination of the absolute amount of the first partial compensation current required to compensate for the vertical differential force applied between the load receptacles (18a, b),- loading the second load receptacle (18b) with the test weight,- energizing the additional moving coil (301a, b) with a second partial compensation current,- Determination of the absolute amount of the second partial compensation current required to compensate for the vertical differential force applied between the load receptacles (18a, b),- Determination of a total compensation current representative of the test weight as the sum of the absolute amounts of the partial compensation currents.
    [12]
    12. The method according to claim 11,characterized,that the substitution weight has approximately half the nominal mass of the test weight and the balance (10) is calibrated by means of the calibration method according to claim 10 to determine the calibration factor of the additional moving coil (301a, b) required for determining the test weight, the additional moving coil (301a, b) is energized during calibration with a calibration current, the current intensity of which is dimensioned such that it is used as a compensation current to compensate for a vertical differential force between the load receptacles (18a, b), which is equal to half of the weight corresponding to the nominal mass of the test weight , would be suitable.
    [13]
    13. A method for determining a test weight of known nominal mass by means of a beam balance according to claim 9, as far as dependent on claim 8, comprising the steps:- loading the first load receptacle (18a) with a substitute weight that is less than the test weight,- energizing the additional moving coils (301a, b) each with a first partial compensation current of the same amount and opposite sign,- Determination of the absolute amounts of the first partial compensation currents required to compensate for the vertical differential force applied between the load receptacles (18a, b),- loading the second load receptacle (18b) with the test weight,- energizing the additional moving coils (301a, b) with a second partial compensation current each of the same amount and opposite sign,- Determination of the absolute amounts of the second partial compensation currents required to compensate for the vertical differential force applied between the load receptacles (18a, b),- Determination of a total compensation current representative of the test weight as the sum of the absolute amounts of all partial compensation currents.
    [14]
    14. The method according to claim 13,characterized,that the substitution weight has approximately half the nominal mass of the test weight and the balance (10) for determining the calibration factors of the additional moving coils (301a, b) required for determining the test weight is calibrated by means of the calibration method according to claim 10, each additional moving coil (301a, b) is energized during calibration with the same calibration current, the current intensity of which is dimensioned such that it is used as the sole compensation current to compensate for a vertical differential force between the load receptacles (18a, b), which corresponds to a quarter of the nominal mass of the test weight Weight force would be suitable.
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    同族专利:
    公开号 | 公开日
    DE102016106695B4|2018-11-08|
    DE102016106695A1|2017-10-12|
    CH712349A2|2017-10-13|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    AT104524B|1924-03-11|1926-10-25|Fegyver Es Gepgyar Reszvenytar|Table scales.|
    US2170798A|1938-01-21|1939-08-29|Toledo Scale Mfg Co|Weighing scale|
    DE2621483C2|1976-05-14|1978-02-16|Sartorius-Werke GmbH , 3400 Göttingen|Electromagnetically compensating beam balance|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102016106695.8A|DE102016106695B4|2016-04-12|2016-04-12|Electromagnetically compensating beam balance, method for its calibration and method for determining a test weight|
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