Title of Invention	AN APPARATUS FOR MEASURING A MASS FLOW
Abstract	AN APPARATUS FOR MEASURING A MASS FLOW

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FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & The Patents Rule, 2003 COMPLETE SPECIFICATION [See Section 10 and Rule 13] "AN APPARATUS FOR MEASURING A MASS FLOW" SCHENCK PROCESS GMBH, of Landwehrstrasse 55, D-64293 Darmstadt, Germany, Original IN/PCT/2001/0907/MUM The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- GRANTED 9 MAR 2005 The present invention relates to an. apparatus for measuring a mass flow. The invention relates to a device for measuring a mass flow, particularly of a bulk material flow according to the Coriolis measuring principle in accordance with the preamble of the patent claim. For a precise ascertaining of the weight of material flows the effective inertia force (Coriolis force) is utilized for the mass determination. The Coriolis force, occurs at the coupling of a moved mass particle with a rotating reference body. For this purpose the material flow is supplied to a disk provided with radial guide vanes, whereby the bulk material is centrifuged substantially perpendicularly to the rotational axis of the disk. The torque moment of the disk rotating with a constant r.p.m. varies in accordance with the Coriolis force, whereby the torque moment change is proportional. Such a measuring device for the continuous ascertaining of the weight of material flows is known from German Patent Publication DE-OS 3,346,145. In that measuring device an impeller rotating with a constant r.p.m. is driven by an electric motor arranged directly above. The motor is supported ia a stationary housing 2 in the manner of a pendulum. A lever arm is attached to the drive motor by means of which the rotatably mounted motor supports itself on a force sensor which is connected with the housing. Thereby, the reaction torque moment of the occurring torquing of the motor housing is transmitted to the force sensor. The sensed force is converted into a torque moment by taking into account the lever arm, whereby the torque moment is precisely proportional to the mass throughput. In that apparatus the motor is suspended like a pendulum and is guided relative to the stationary housing by ball bearings which can falsify the torque moment measurement by their friction. Even if one ascertains this bearing friction by a measurement made during an empty run and then takes the measurement into account, different bearing frictions occur under load operating conditions so that with a motor supported at one side, due to a non-uniform lubrication on the bearing walls, frictions occur that cannot be determined and which falsify the measuring result. A torque moment measuring device with a torsion articulation is known from European Patent Publication EP 0,590,187 Al for avoiding such non-uniform friction effects. The torsion articulation introduces the drive torque moment through three vertically arranged leaf springs into at least two separate force sensor elements, whereby the drive torque moment of the motor always bears symmetrically to the rotational axis onto the two force measuring elements. However, for this purpose at least two force measurinc elements are required which increase the apparatus effort and exDense of the measuring device. 3 therefore, it is the object of the invention to improve a measuring device of the type mentioned above in such a way that with a simple means a high measuring precision is achievable. According to the present invention there is provided an apparatus for measuring a mass flow., particularly a bulk material flow, in accordance with the Cdriolis measuring principle, including an impeller driven by a motor with a constant r.p.m., wherein the material flow is supplied to the impeller and detoured radially, wherein a torque moment measuring device measures the drive torque moment, wherein the drive torque moment is transmitted by leaf spring elements which are flexible in response to bending loads effective in a rotation direction and stiff against bending in the longitudinal direction, characterised in that the drive torque moment is transmitted free of axial forces to a force measuring element through a.pivot bearing with at least two horizontal and angularly spaced leaf spring elements which are arranged to cross each other, whereby the crossing point of the leaf spring elements is positioned on a provided rotational axis. The invention has the advantage that due to the crosswise arranged leaf spring elements, the measuring device always remains fixed on a predetermined rotational axis. Thus, the lever arm length for bearing on a stationary force measuring device cannot vary. 60 that a good zero point, stability and measuring value constant is achievable. By these features simultaneously a good insensitivity to temperatures is achieved because the heat expansions can become effective on the lever arm length only in a negligible manner. According to a special type of embodiment of the invention with an axial ball or toe bearing, it is an advantage that thereby the weight of the drive train is transferrable substantially with Low friction onto a stationary housing section, whereby friction caused measuring errors have become substantially avoidable. The drive train includes the impeller, the drive shaft, and the motor. Due to the fact that in such an embodiment the rotation bearing does not have to take up any axial forces, hardly any force shunting effect takes place so that with such a measuring " . device even small conveying volumes are measurable in an 4 advantageous way and manner. In such an axial support it is also advantageous that it can be protected in a simple manner against contaminations so that precision is assured over long periods of time. In connection with a further advantageous type of embodiment with the aid of a fluid bearing in the lead through area a friction free horizontal mounting of the drive shaft is achieved so that also here friction related measuring errors are additionally avoided. Simultaneously such a fluid or air bearing assures an excellent sealing to the bulk matrerial space so that the measuring device is advantageously also operable with excess pressure without any apprehension that a contamination and friction increase of the bearing might occur. The invention will be explained in more detail with reference to an example embodiment that is shown in the drawings, wherein: Fig. 1 shows an apparatus for measuring the mass flow; Fig. 2 shows an enlarged illustration of the torque moment measuring device in a side view thereof; and Fig. 3 shows a top plan view of the torque moment measuring device. Fig. 1 of the drawings shows schematically a device for measuring the mass flow in a sectional view in which the impeller 2 is arranged above the drive motor 9 on a lengthened drive shaft 5 and wherein the drive moment is transmitted through a pivot bearing element 12 onto a force sensor 11 as a torque moment measuring device. The mass flow which is mostly a bulk material flow is guided through a tubular bulk material supply 1 to the center of an impeller 2. The impeller 2 is driven by the drive motor 9 with a constant speed, whereby the bulk material flow is horizontally deflected and flows downwardly through the surrounding bulk material housing 4 and through a bulk material outlet 7. The impeller 2 is mounted on an elongated vertical drive shaft 5 which is mounted by an air bearing 3 horizontally relative to the bulk material housing 4. By means of this air bearing 3 simultaneously a sealing is achieved relative to the bulk material housing 4 so that a contamination of the bearing 3 is substantially avoided. Thereby, however, the air pressure in the bearing 3 must be higher by a certain value than the pressure in the bulk material housing 4. This bearing 3 is thus well suited for bulk material flows which are transported through the measuring device by excess pressure. Such an air bearing 3 is advantageousiy also substantially free of friction so that the measuring result cannot be falsified by friction losses. This is particularly important for measuring small mass flows because here even smal,l friction losses can lead to relatively large measuring errors. This air bearing 3 is supplied with excess pressure through an air pressure coupiinq 6 at the housing section 4. Such an excess pressure is usually available 6 centrally in an industrial area of use. Such an air bearing 3 may, however, also be operated with other fluids suitable for such bearings as far as this is necessary for structural or supply technical reasons. The bulk material housing 4 is secured on a motor housing 8 positioned below and constituting a stationary member. The drive motor 9 is vertically arranged in the motor housing 8. Thereby, the motor 9 is secured at its bottom side on a head plate 10 which supports the entire drive train of the impeller, the drive shaft and the motor on a pivot bearing element 12. The pivot bearing element 12 comprises substantially an upper bearing bushing 15 and a lower bearing bushing 18 between which a ball 14 is arranged as an axial bearing support. The torque moment measuring device 11 is simultaneously integrated in the pivot bearing 12. The device 11 supplies an electrical signal that is proportional to the throughput value or throughput amount of the bulk material flow. The pivot bearing 12 with the torque moment measuring device 11 is shown in detail and enlarged in Figs. 2 and 3, whereby the same pares in the shown Figs, are provided with the same reference characters. The upper bearing bushing 15 of the pivot bearing 12 is rigidly connected with the head plate 10 and arranged symmetrically to the rotational axis 12 of the motor 9. The lower bearing bushing 18 is coaxially introduced into the upper bearing bushing 15 which is open downwardly, whereby tne lower bearing bushing 18 comprises in its upper section a recess 7 for the ball forming an axial thrust bearing. Due to this recess the ball 14 is fixed on a predetermined rotational axis. The lower bearing bushing 18 is provided in its lower section with a ball pan 20 by means of which the lower bearing bushing 18 is attached vertically and symmetrically to the provided rotational axis 13 at the motor housing 4 by means of a securing screw 19. Both bearing busliings 15 and 18 are laterally spaced from each other so that they are rotatable relative to each other without contact. Leaf spring elements 16, 17 are provided horizontally and crossing each other by 90° in the overlapping area of the two cylindrical bearing bushings 15 and 18. One end of the leaf springs is secured to the upper bearing bushing 15, while the other end of each leaf spring is secured to the lower bearing bushing 18. Since the spring elements 16 and 17 crossing each other are passing through the hollow space of the lower cylinder 18, two lateral cut-outs are provided on the opposite side of the Lower bearing bushing 18 for passing the spring elements 16 and 17 through these cut-outs which make possible a certain rotation angle between the two bearing bushings 15 and 18. Thereby, the leaf spring elements 16 and 17 are so constructed that they are easily bendable in the rotational direction of the drive motor 9, but are stiff against bending,in the longitudinal directicn. Due to the fact that the leaf spring elements 16 and 17 are arranged angularly displaced, they cross each other on the provided rotational axis 13, thereby fixing both bearing bushings 8 15 and L8 symmetrically to the rotational axis 13. Thereby, another crossing angle as well as more than two spring elements may be provided as far as this would be advantageous with due regard to the intended construction of the bearing element. However, it must be assured that the fixing takes place on the provided rotational axis 13. In the vertical direction the leaf spring elements 16 and 17 are arranged in different planes so that a direct contact between the spring elements 16 and 17 is avoided. Instead of using a ball 14, the axial thrust bearing can be a toe bearing or comparable bearings may be provided as far as these assure an axial thrust bearing substantially free of friction about the rotation axis 13. A lever arm 24 is secured to the outer circumference laterally and at a right angle to the center of the upper bearing bushing 15. A pressure member 23 is secured horizontally and at a right angle to the end of the lever arm 24. Thereby, the pressure member 2 3 bears on a force measuring element 22 which is rigidly secured with the bottom of the stationary motor housing 3. The force measuring element 22 may be advantageously embodied by a bending beam equipped with strain gages, which bending beam provides an electrical signal that corresponds to the force. In operation of the measuring device, tne motor 9 bears with its drive moment radially on the force measuring element 22, whereby the drive moment is determined with the aid of the Known lever 9 arm 24. The conveyor throughput and/or the conveyed amount can be ascertained from the drive moment in a known manner. Thereby it is assured by the special arrangement of the leaf spring elements 16 and 17 that the rotational axis 13 that is mounted in a fixed position is not displaced out of its radial position to thereby change the predetermined lever arm length even for large load changes. Due to such an angularly displaced, crossing pivot bearing 12, leaf springs 16 and 17 that are very soft in the rotational direction may be used, whereby hardly any force shunting effect occurs that could falsify the measured value. As a result, the present measuring device is useable also for relatively small conveyor throughputs where high precision requirements must be met because this torque moment transmission which is substantially free of force shunting, causes only small measuring errors. These small measuring errors are further reduced in connection with small conveyor throughputs in that air bearings 3 and axial bearings 14 are used which are substantially friction free, whereby friction and force shunting errors can hardly occur in the entire measuring device. Such bearing supports which are substantialLy free of friction and free of force shunting can also be used advantageously in measuring devices for large conveyor throughputs. Gear drive motors or intermediate gears are useabLe in such context provided they are sufficiently free of friction or their friction car. be compensated, either by calculation or constructively. 10 Such a bearing support substantially free of friction and free of force shunting can also be used for suspended drive trains with overhead drives- In that case the inner bearing bushing 18 must be so constructed that the ball 14 is arranged below the bushing cover in a lateral fixation. The outer bearing bushing 15 must then be so constructed that at least one cross piece is provided which passes through the inner bushing 18 below the ball 14. Thus, the axial force of the drive train is transmitted through the cover of the inner bushing and through the ball 14 arranged overhead, onto the cross piece of the outer bushing 15 so that by chese features the same function is assured as in a motor mounting 12 arranged belaw the bulk material container 4. 11 We Claim: 1. An apparatus for measuring a mass flow, particularly a bulk material flow, in accordance with the Coriolis measuring principle, including an impeller driven by a motor with a constant r.p.m., wherein the material flow is supplied to the impeller and detoured radially, wherein a torque moment measuring device measures the drive torque moment, wherein the drive torque moment is transmitted by leaf spring elements which are flexible in response to bending loads effective in a rotation direction and stiff against bending in the longitudinal direction, characterised in that the drive torque moment is transmitted free of axial forces to a force measuring element (22) through a pivot bearing (12) with at least two horizontal and angularly spaced leaf spring elements (16, 17) which are arranged to cross each other, whereby the crossing point of the leaf spring elements (16, 17) is positioned on a provided rotational axis (13). « 2. The apparatus as claimed in claim 1, wherein the leaf spring elements (16, 17) are arranged in a rotatable bearing element (12) (pivot bearing), which on one side is rigidly connected to the drive motor (9) and on the other side is rigidly connected to a stationary housing section (8), and which is mounted in an extension of the provided rotational axis (13). 3. The apparatus as claimed in claim 1 or claim 2, wherein the pivot bearing (12) comprises at least two parts (15, 18) which are rotatable about the provided rotational axis (13) in opposition to each other, and which are connected to each other by the leaf spring elements (16, 17), whereby only the bearing element (15) connected to the drive (9) is movable relative to the other bearing element (18). 12 The apparatus as claimed in one of the preceding claims, wherein the parts (15, 18) that are rotatable in opposition to each other, are constructed as cylindrical bushings which partially grip coaxially one into the other. The apparatus as claimed in one of the preceding claims, wherein an axial thrust bearing (14) is provided through which the weight of the drive train above the provided rotational axis (13) is transmitted substantially free of friction into a stationary-apparatus part (8). The apparatus as claimed in claim 5, wherein the axial thrust bearing (14) is arranged on the provided rotational axis (13), whereby the weight force is transmitted substantially point shaped through a ball or toe bearing arranged in the area of the rotational axis (13) to the stationary housing part (8). The apparatus as claimed in claim 5 or 6, wherein the axial thrust bearing (14) is integrated in the pivot bearing (12) and is arranged between the two bearing elements (15, 18) that are rotatable in opposition to each other. The apparatus as claimed in one of the preceding claims, wherein the drive train is mounted horizontally in the area of the drive shaft (5), whereby the horizontal bearing (3) is so constructed that substantially no friction occurs. The apparatus as claimed in claim 8, wherein the horizontal bearing (3) of the drive shaft (5) is constructed as an air bearing, which simultaneously seals the lead through of the drive train into the bulk material housing (4). 13 10. The apparatus as claimed in claim 8 or claim 9, wherein the fluid bearing (3) is constructed as an air bearing which is arranged in the transition area between the drive shaft (5) and the impeller (2). 11. The apparatus as claimed in one of the preceding claims, wherein the drive train is so arranged that the motor (9) is provided below the impeller (2) and the pivot bearing (12) as well as the axial bearing element (14) are provided therebelow. 12. The apparatus as claimed in one of the preceding claims, wherein the drive train is so arranged that the motor (9) is provided above the impeller (2) and the pivot bearing (12) and axial bearing element (14) are provided thereabove. Dated this the 30th day of July, 2001 [JAYANTA PAL] Of Eerrifry & Sagar ATTORNEY FOR THE APPLICANT[S] \H-

Documents:

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in-pct-2001-00907-mum-cancelled pages(09-03-2005).pdf

in-pct-2001-00907-mum-claims(granted)-(09-03-2005).doc

in-pct-2001-00907-mum-claims(granted)-(09-03-2005).pdf

in-pct-2001-00907-mum-correspondence(ipo)-(03-01-2007).pdf

in-pct-2001-00907-mum-correspondence1(27-08-2007).pdf

in-pct-2001-00907-mum-correspondence2(09-07-2007).pdf

in-pct-2001-00907-mum-drawing(09-03-2005).pdf

in-pct-2001-00907-mum-form 1(30-07-2001).pdf

in-pct-2001-00907-mum-form 19(20-02-2004).pdf

in-pct-2001-00907-mum-form 1a(09-03-2005).pdf

in-pct-2001-00907-mum-form 2(granted)-(09-03-2005).doc

in-pct-2001-00907-mum-form 2(granted)-(09-03-2005).pdf

in-pct-2001-00907-mum-form 3(09-03-2005).pdf

in-pct-2001-00907-mum-form 3(30-07-2001).pdf

in-pct-2001-00907-mum-form 5(30-07-2001).pdf

in-pct-2001-00907-mum-form-pct-ipea-409(30-07-2001).pdf

in-pct-2001-00907-mum-form-pct-isa-210(30-07-2001).pdf

in-pct-2001-00907-mum-petition under rule137(09-03-2005).pdf

in-pct-2001-00907-mum-power of authority(09-03-2007).pdf

in-pct-2001-00907-mum-power of authority(30-07-2001).pdf