CN1188232A - System for checking calibration of gravimetric feeders and belt scales - Google Patents
System for checking calibration of gravimetric feeders and belt scales Download PDFInfo
- Publication number
- CN1188232A CN1188232A CN97111134A CN97111134A CN1188232A CN 1188232 A CN1188232 A CN 1188232A CN 97111134 A CN97111134 A CN 97111134A CN 97111134 A CN97111134 A CN 97111134A CN 1188232 A CN1188232 A CN 1188232A
- Authority
- CN
- China
- Prior art keywords
- weighing
- section
- belt
- roller
- span
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 claims abstract description 22
- 238000005303 weighing Methods 0.000 claims description 227
- 238000012795 verification Methods 0.000 claims description 53
- 239000000463 material Substances 0.000 claims description 39
- 238000007599 discharging Methods 0.000 claims description 21
- 238000012360 testing method Methods 0.000 abstract description 61
- 239000013590 bulk material Substances 0.000 abstract description 4
- 230000000712 assembly Effects 0.000 abstract 1
- 238000000429 assembly Methods 0.000 abstract 1
- 239000003245 coal Substances 0.000 description 8
- 238000011144 upstream manufacturing Methods 0.000 description 7
- 238000001514 detection method Methods 0.000 description 3
- 230000014509 gene expression Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000004088 simulation Methods 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000002153 concerted effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000007665 sagging Methods 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Landscapes
- Structure Of Belt Conveyors (AREA)
Abstract
There is provided an system and method for calibrating weigh assemblies of bulk material feeders using test chains of known weight and pitch. In particular, the present invention is a calibration checking system for a belt-type gravimetric feeder or conveyor having a weigh span section and comprises a continuous conveyor belt, at least one pair of support rollers and at least one weigh roller. A particular weigh roller is disposed under an upper strand of the conveyor belt and equidistant from each of the support rollers so that they are in planar alignment with one another. The calibration checking assembly also comprises a test chain having a chain pitch that is integrally divisible into the pitch of the weigh span section. In addition, portions of the conveyor belt on both sides of the weigh span are inclined equally at a single particular angle relative to the weigh span section. The calibration checking system further comprises a pair of load cells coupled to the ends of the weigh roller and a processor coupled to the loads cells for determining an optimal elevation for the weigh roller. The load cells and processor detect belt tension of the conveyor belt and analyze weigh load in relation to the belt tension.
Description
The system that the present invention relates generally to check the align mode of meter pipe banding pattern batcher and conveyor to use, this batcher and conveyor are used for loose unpacked material being carried out continuous weighing when loose unpacked material betransported by weighing of corresponding batcher during span.Usually, this type of gravimetric feeder or conveyor comprise an entrance zone, threshold zone, a discharging section and the span section of weighing between them.More particularly, the present invention relates to the system that the align mode of a specific weighing platform of a kind of check is used, method is that a precision measurement chain that is placed the span of weighing by corresponding batcher or conveyor is weighed and the known weight of indication weight and this testing chain is compared.Precision measurement chain by utilizing known weight and spacing and before the check align mode weighing platform is established some physical attribute, this system can provide result highly reliably.
Be used for generally knowing in this technical field to the continuous gravimetric feeder or the conveyor of receiver bin or metallic ore stove shipping bulk material (as broken coal) from feeder hopper.This type of batcher generally includes one around a pair of conveying belt and weighing platform that rotates relative to the belt pulley of arrangement, and the latter is used for loose unpacked material being carried out continuous weigh by weighing of a qualification in advance during the span section when loose unpacked material.Particularly, the last band of belt can be subjected to the supporting of the backing roll of a plurality of gaps predetermined value.Settled interval between any two backing rolls of the roller of weighing to define the length of the span section of weighing just betwixt.When loose unpacked material by the weighing during the span section of gravimetric feeder, a microprocessor that is connected on this weigh span section and belt transmission (motor) is determined delivery rate, promptly in the unit interval by the nt wt net weight of the loose unpacked material of conveying belt carrier band.Like this, by the monitoring delivery rate, can control batcher speed and make it meet instantaneous loose unpacked material transmission requirement.The conveyor that belt scale is housed also can use the microprocessor that is connected on the weighing platform, when loose unpacked material when weighing span, the tested weight of this weighing platform accumulative total.Such conveyor is used to the shipping bulk material and does not control transfer rate.
Usually, this weighing device comprises the roller of weighing, and is used for the weigh weight of loose unpacked material in the span section of METHOD FOR CONTINUOUS DETERMINATION conveyor.This roller of weighing is bearing between two backing rolls by a piezo-electric type or strainmeter (strainometer) type force cell transducer, and this force cell transducer produces one corresponding to the current loose unpacked material in the span section of weighing and the general assembly (TW) of tare weight of being placed in.When loose unpacked material when weighing above the span section, microprocessor that is connected on this device is accepted as the information of the general assembly (TW) of loose unpacked material weight and platform tare weight sum and is handled this information, thus calibration and control the operation of this weighing device and gravimetric feeder.
Conventional gravimetric feeder and conveyor utilize a static benchmark load to calibrate.What calibrate is at first to compensate gross weight, then a static load of being made up of accurate known weight is applied on the suitable parts of the span section of weighing, and calibrates microprocessor control then to show pivot weight.This calibration steps may always can correctly not calibrated the span section of weighing, and because pivot weight can not cause the variation of belt tension and deflection (for example sag of belt) or reproduce structural deviation and may produce error, these structural deviation otherwise material load on the conveying belt of gravimetric feeder or conveyor occur.Simultaneously, with the calibration of the Weight apparatus that hangs from above the time, may since the error that the bearing friction of the roller of weighing when loading produces be left in the basket.
The calibration of gravimetric feeder and conveyor obtains verification or proof by the material test.In fact, when the above-mentioned relevant calibration steps that transmits error has problems, carry out a material test usually with its correctness of final inspection.Verification is done in such a way that a certain amount of loose unpacked material of normally carrying by batcher exactly on the span section of weighing, the pivot weight of measuring on the large-scale precision batch scale before or after testing definite loose unpacked material weight and testing is compared.Because its manpower expense and Equipment Downtime, the material test is usually as last resort.Secondly, if be not to pay close attention to details when testing, serious potential error might appear.These be included in be transported to scale during material minimizing and moisture loss, owing to flox condition is bad material is stayed in the hopper, and the tare weight of conveying arrangement is considered to owe to work as.
Outside the material test, testing chain has been used as the benchmark load of test gravimetric feeder and conveyor.Because testing chain provides the feasible simulation of the load of the span section of weighing,, they when need scale is recalibrated or repaired so being used to indication.Carrying out having finished initial assembling usually after the material test, testing chain is added by the span section of weighing thus, writes down testing chain with respect to the position of the fixed datum on batcher or the conveyor frame and the weight of record indication.After this periodically check align mode, method is that testing chain is placed on the span section of weighing, and they are collimated to the fixed reference position on batcher or the conveyor frame again and write down new weight readings.Surpass specific tolerance threshold value if testing chain weight readings subsequently departs from, just must recalibrate again with a certain amount of loose unpacked material of weighing in advance of another part.
Conventional system is current not to have the use test chain as directly calibrating or weight basis.Industrial sector is felt unstable result that testing chain produces and to its position sensing on conveying belt usually.Because insecure character of awaring of the chain that position sensing causes test, testing chain only is used as the benchmark on the span section of weighing, and is used to detect the scale changes of properties.The result is, above-mentioned material detection calibration has been the unique method that is used to discern the problem that the span section of weighing with batcher exists.Therefore, although the material detection calibration is inconvenient and the expense height, this kind calibration still is used as preferred calibration steps usually in industrial sector.
Chain test can load with the mode that the is similar to loose unpacked material span section of weighing to gravimetric feeder, but its produces material is loaded the simulation that the belt tension that causes changes.In addition, the chain test has the position instability that can prove significantly.
Therefore, the present invention is the calibration verification system of the relevant issues of a kind of material detection calibration that has overcome above-mentioned routine and pivot weight system.
The invention provides a kind of testing chain with specific chains distance, this specific chains distance is the span spacing of weighing based on the corresponding conveyor or the batcher of testing chain.Gravimetric feeder according to calibration verification system of the present invention has specific structural geometry simultaneously, and this weighing device has the device of compensation belt tension, so that be provided for checking the height system accurately and reliably of the align mode of gravimetric feeder or belt scale.In fact, calibration verification system of the present invention can obtain the reading that is complementary for ± 0.1% testing chain known weight with accuracy, and conventional calibration verification system method has been ignored the actual weight of chain and the current indication weight that records is compared with the indication weight of old record.
The present invention is the calibration verification system that a kind of belt-type gravimetric feeder or conveyor are used, this batcher or conveyor equipped have entrance zone, threshold zone, the belt scale of the span of weighing section and discharging section, in brief, it comprises that a continuous conveying belt, at least one pair of backing roll and at least one are placed in the roller of weighing between them.This conveying has the upper and lower that moves in opposite directions and center on a pair of belt pulley arrangement.Each is placed under this top backing roll and spaced apart border with the span section of weighing that limits conveyor.This span border of weighing distance between the center line of two adjacent backing rolls of the roller or the roller arrangement of weighing that further is defined as directly and weighs.This at least one roller of weighing is positioned under this top, and in the occasion more than the roller of weighing, the geometric center and a pair of backing roll of this roller combination are equidistant.This comprises the roller of the span of weighing, i.e. at least one weigh roller and more than one backing roll are preferably parallel to each other and become rectangular area to collimate and perpendicular to the belt direct of travel.The span section of weighing with independent roller of weighing of gravimetric feeder or conveyor has the span roll spacing of weighing, the latter's preferably equal to weigh half of distance between span section two borders.In multi weighing roller system, the distance between each roller is constant and determines this roll spacing.The space of weighing outward between roller and the adjacent backing roll also by chance is a roll spacing.
This calibration test equipment also comprises a distinguishing chain apparatus, and the latter has a plurality of conveying belt top and chain rollers by its span section of weighing of being placed in.This chain has the chain pitch corresponding to distance between the chain roller center line, the roll spacing of the aliquot span section of weighing of the latter.This chain has first end, center section and the second end on entrance zone, threshold zone, the span of weighing section and the discharging section that longitudinally is distributed in batcher respectively, and wherein the weight of center section and roll spacing are controlled more carefully than the weight and the roll spacing of each first and second end.If chain and the non-integral used can be divided, the indication weight of this chain will be the function of its lengthwise position on the plane of weighing.
In addition, conveying belt requires to be arranged in symmetrically on the roller of the span section of weighing.Therefore, the top of conveying belt comprises that is placed in entrance zone, threshold zone and the first belt section between the span section of weighing, and the latter has a specific entering angle that enters first backing roll.The top of conveying belt comprises that also is placed in the discharging section and the second belt section between the span section of weighing, and the latter has a specific receding angle that withdraws from second backing roll.No matter bear much loads on the conveying belt, this independent specific angle of the first and second belt sections all keeps equal.Entering angle and receding angle are that belt is flexible, the function of belt tension and load.
This calibration test equipment also comprises the perturbation analysis device on the opposite ends that is connected in this at least one roller of weighing, and is used to this at least one roller of weighing to determine an optimum height.This perturbation analysis device comprise be used for analyzing extend through relevant with the belt tension of conveying belt weigh the span section the load of weighing device and produce one at belt tension and be approximately 10% to 50% device that is preferably about 20% step change.
Preferably, this perturbation analysis device comprises and a pair ofly is connected in force cell (load transducer) on these at least one roller two ends of weighing and one and is connected in this to the processor on the force cell, is used for determining the height error value of this at least one roller of weighing.On the weighing platform of settling like this, the analytical equipment of this perturbation analysis device can determine which end of this at least one roller of weighing need be adjusted height and adjust direction is upwards or downwards.This perturbation analysis device also can be connected in the system, and this weighing platform load is added up by an independent force cell machinery and measures there.
Fig. 1 is one and typically has short center line to center line, the inlet side cross-sectional, view to the gravimetric feeder of discharge port size, wherein loose unpacked material feeding on conveying belt, weighs and discharges from being with;
Fig. 2 A is the part side view of the preferred embodiment of a general expression weighing platform;
Fig. 2 B is the top plan view of Fig. 2 A preferred embodiment;
Fig. 3 A is the part side view of Fig. 2 A preferred embodiment, and one of them testing chain is bearing on a conveying belt and a plurality of roller;
Fig. 3 B is the top plan view of Fig. 3 A preferred embodiment;
Fig. 4 is the weigh part side view of the conveying belt on roller and the belt pulley of a pair of backing roll of being installed in of gravimetric feeder,, and one of them is positioned on its correct position according to testing chain of the present invention;
Fig. 5 is the part side view of conveying belt shown in Fig. 4, wherein this testing chain maximum upstream position of being moved to the preferred embodiment and being allowed;
Fig. 6 is the part side view of conveying belt shown in Fig. 4, and wherein this testing chain has been moved to above its maximum downstream position shown in Fig. 8, so the inappropriate testing chain in a kind of position of illustration;
Fig. 7 is the part side view of preferred embodiment, wherein is connected on the force cell more than one the roller of weighing and is placed between two backing rolls;
Fig. 8 is the simplification top plan view of roller swing, the relation between swing of illustration roller and the roller arrangement rotating surface.
Calibration verification system of the present invention is used for a belt-type gravimetric feeder or conveyor device, and the latter has an entrance zone, threshold zone, weigh a span section and a discharging section.This system comprise a continuous conveyor of settling around a pair of belt pulley, two or more be placed in that backing roll below the conveying belt top and one are placed in below this top and with the equidistant roller of weighing of each backing roll.For the preferred embodiment, this system comprises a pair of backing roll and the roller of weighing, and these backing rolls are collimations level and parallel to each other in the plane direction of collimation.This roller of weighing is placed in below this top and is equidistant with each backing roll.Preferably, roller and the backing roll plane collimation each other of weighing.The best collimation parallel to each other of roller of forming the span section of weighing.
In addition, belt support outside on the span of the weighing section both sides and the both sides preferably is made up of the span roll spacing roller far away of weighing in interval, but can use other supporting member such as slider disc or driving belt instead, but they must be settled like this, make the entering angle of the conveying belt by the plane of weighing equate and keep symmetry with receding angle.
Calibration verification system of the present invention is applied to a kind of belt-type batcher or conveyor that is subjected to the error relevant with the test of chain.This system runs into this type of error of testing chain with appropriate designs and the corresponding span section collimation step of weighing.About testing chain, the chain pitch of this testing chain is whole can the branch in the roll spacing of the weighing span section of batcher or conveyor preferably.Weighing span section preferably is divided into the same roll spacing of two equal spans by the weighing roller, and the side chain of testing chain is preferably surveyed side direction and evenly distributed by the span section of weighing.At chain pitch is not that perhaps under opposite extreme situations, the roll spacing of these two spans of weighing is unequal under the integral body situation about can divide, and this calibration verification system can calculate suitable chain pitch and position.Simultaneously, the passing through of this chain its weight of middle part that the span section settles of weighing is uniformly along its length, and known its uncertainty is than 5 to 10 times of the degree of accuracy of relevant weight scale.Simultaneously, this middle part is adjusted like this, makes it almost equal in the weight of the loose unpacked material that will weigh under normal operation.As for batcher or conveyor, the physical dimension of the span of weighing section (being included in a roll spacing of any side of the span of weighing) is adjusted according to calibration verification system, therefore, the present invention provides high degree of accuracy by utilizing preferred testing chain, and guarantees insensitivity to belt tension by making the span section of weighing accept belt tension perturbation analysis and adjustment.
With reference to Fig. 1, provide a typical gravimetric feeder among the figure especially, total represents with label 10.Gravimetric feeder 10 is a kind of band conveyors that can use the specific pattern of calibration verification system of the present invention.Gravimetric feeder 10 expression a kind of to the practical short formula center line of accurately weighing to center line, enter the mouth to the discharge port device, this machine comprises the continuous or round-robin conveying belt 12 of a loop form, this loop has on one band or top 14 and once is with or bottom 16, is used for from hopper 20 to receptacle (as feed bin or stove) 22 delivery of bulk material 18 (as broken coal) continuously.As what see from the skeleton view of Fig. 1, conveying belt 12 is settled around a pair of belt pulley (24,26), and this is to belt pulley 28 driving and conveying belts 12 along clockwise direction.The end that loose unpacked material 18 is preferably in belt top 14 is evenly distributed on the conveying belt 12 and is transported to the other end on top 14, and material is fallen into receiver 22 there.When loose unpacked material 18 is transported to the other end on top 14 of conveying belt 12, the weigh plane 32 of material by comprising in the span of weighing.
When loose unpacked material by the weighing during plane 32 of conveying belt 12, weighing device 30 loose unpacked material 18 of weighing continuously.The border of the planar section of weighing 32 is determined by the position that is placed in two backing rolls (34,36) under conveying belt 12 tops 14.Therefore, the distance of the backing roll that separates (34,36) or span are corresponding to the length of the planar section 32 of weighing.Simultaneously, weighing device 30 comprises one of conveying belt 12 roller 38 of weighing.According to a preferred embodiment of the invention, backing roll (34,36) is placed in the opposite sides thereof of the roller 38 of weighing, and wherein each backing roll (34,36) is in the identical or substantially the same surface level with the roll spacing of weighing between the roller 38.Roller 38 by chance is positioned in the middle of the backing roll (34,36) because weigh, so the distance between weigh roller 38 and the arbitrary backing roll (34,36) is corresponding to half of distance between the roll spacing of the planar section of weighing or two backing rolls.
Fig. 2 A and 2B are the more general expressions of the preferred embodiment of Fig. 1.Particularly, Fig. 2 A and 2B concentrate on the geometric aspects of the used band conveyor scale of gravimetric feeder 10, and roll spacing P1, P2, P3 and the P4 of its central span equate.Though be not to be the part on plane 32 of weighing, the backing roll of outside (33,37) preferably is placed in the roll spacing P of the span of weighing of the upstream and downstream on the plane 32 of weighing respectively
x=P
1Place, and by such vertical adjusting makes the entering angle of under load-carrying sagging belt 14 and receding angle α equally by the plane 32 of weighing.Backing roll (34,36) is parallel with the roller 38 of weighing, and makes all angle θ all be equal to each other and forms the angles of 90 degree with the direct of travel on the top 14 of conveying belt 12.
With reference to Fig. 3 A and 3B, preferred calibration test equipment comprises a distinguishing testing chain 50 that longitudinally is distributed on conveying belt 12 tops 14, also promptly is divided into entrance zone, threshold zone 52, the span of weighing section 54 and discharging section 56.As shown in Fig. 3 B, testing chain 50 can comprise multiply side chain 66, and they are evenly distributedly by the plane 54 of weighing, to adapt to the bearing capacity in plane 54 work of weighing.The middle section 58 of testing chain 50 extends through the span section 54 of weighing of batcher.The chain pitch 60 of testing chain 50 is corresponding to the distance between the roll center of adjacent chain roller, and the roll spacing 62 of the span of weighing of the span section 54 of weighing is corresponding to half of distance between the center of rotation that is backing roll 34 and 36 of two borders of the span 54 of weighing.Therefore, weigh the roll spacing 62 of span corresponding to from the distance of roller 38 of weighing to one of backing roll (34,36).In addition, for the purpose of economy, the section weight that is arranged in entrance zone, threshold zone 52 and discharging section 56 of testing chain 50 and chain pitch there is no need to resemble accurate control the section that is positioned at weighing platform section 54 58 of testing chain 50.The weight precision of the chain member on the weight platform section 54 must remain on five to ten times of the trueness errors of the relevant weight scale of its error ratio.Because the correlativity between the roll spacing 62 of the chain pitch 60 and the span of weighing, the tolerance build-up of any one group of continuous chain member that comprises in the roll spacing 62 of the span of weighing 54 must keep less than ± 0.01%.In addition, chain 60 tunnel span roll spacing 62 of weighing of span section 54 of must aliquot weighing.
Accurate and the reliable performance of the height of testing chain 50 also derives from the precision that is used for measuring section 58 in the testing chain.For preferred embodiment, 5 to 10 times of the known trueness errors than relevant weight scale of the weight error of middle section 58.In many cases, the gravimetric feeder batcher 10 as shown in fig. 1 precision that transmits loose unpacked materials be better than ± 0.25%.Therefore, for preferred testing chain 50, the weight precision of the middle section 58 of testing chain 50 is known not to be worse than ± and 0.05%.Therefore, the weight of testing chain 50 of the present invention is to measure with the degree of accuracy more much higher than conventional chain, and the increment weight of conventional chain is by the general assembly (TW) of chain is measured divided by its length.
With reference to Fig. 7 and Fig. 5, owing to have the step disk and the power wheel of backing roll 33 and 37 (shown in Fig. 3 A) use that replaces the outside, the position of testing chain 50 on conveying belt 12 tops 14 also is important.The testing chain of preferred embodiment is made up of the side chain that reaches stereotyped writing, and per share side chain has 25 rollers.The coal dead weight capacity that the number of side chain can run into usually near (simulation) batcher 10, and the roller number in the per share side chain satisfies the width (for example 36 inches) of the span section 54 of weighing.
The design of other batcher and conveyor may require more or less strand side chain and the chain roller number in the per share side chain.As mentioned above, the weight in stage casing 58 is known is high-precision.On the contrary, for the purpose of economy, the weight of side chain 68 is not controlled in such tolerance outside middle section 58 both sides.Fig. 4 represents the maximum downstream position of testing chain 50 on top 14, and Fig. 5 represents the maximum upstream position of testing chain 50 on top 14.
The some problems that produce when Fig. 6 illustration testing chain extends beyond shown in Fig. 4 and Fig. 5 to greatest extent.The outside 68 of chain 50 is positioned at weighs above the span section 54, the precision of the calibration verification system of therefore having traded off.Simultaneously, the outer roller number that is placed in span section 54 upstreams of weighing may become and can not cover the upstream belt by the equivalent that will introduce the weighing platform roll spacing of cantilever error very little.The cantilever error is because the following former thereby inaccuracy (biased error) that produces, and this reason is the variation that the load effect on the conveying belt 12 of span section 54 either sides of weighing that the rigidity by conveying belt 12 causes causes entering angle and receding angle α.In addition, the downstream part that is suspended on the belt pulley 26 of testing chain 50 can tensioning testing chain 50, the load thereby influence is weighed on the span section 54.
Cantilever error as the direct result of belt rigidity can reduce to minimum owing to some aspect.Testing chain 50 should stride across gap between downstream backing roll 36 shown in Fig. 4 to Fig. 6 and the power wheel 26 or the gap between downstream backing roll 36 shown in Fig. 2 A, 2B, 3A and the 3B and the backing roll 37 and reach and be not more than ± tolerance of 1 chain pitch.Kindred circumstances also is applicable to the upstream, particularly when the front of upstream backing roll 34 is step disk but not backing roll 33.When using step disk to replace backing roll 33, the correct height of dish is most important.Therefore, for fear of the cantilever error, the entrance zone, threshold zone 52 on the top 14 of conveying belt 12 and discharging section 56 must reproduce entering angle and receding angle α, so that keep symmetry on each backing roll 34 and 36.This angle [alpha] is the function of belt stretch-draw amount of deflection and load size.
With reference to Fig. 7, also consider the variation scheme of the preferred embodiment of the present invention.In Fig. 7, can be at the roller of settling between the backing roll more than 38 and connecting on force cell of weighing.
With reference to Fig. 8, the calibration verification system of preferred embodiment also comprises the perturbation analysis device that is connected on the roller opposite ends of weighing, and is used to measure the optimum height of roller of weighing.This disturbance device provides the solution of roller swing (beat) problem.The roller that herein schematically illustrates can or backing roll 34 and 36 or the roller 38 of weighing.When swing appears in roller, just can not correctly adjust the height of the roller of weighing.This problem is that the span of weighing section is corresponding to the average rotating surface of all rollers.Therefore, even the center of axle is when being in sustained height, also may crooked (crooked) by the span section of weighing that backing roll (34,36) forms.
Fig. 8 represents the roller 200 of an inhomogeneous outside surface 204 that has center of rotation 202 and amplify.Illustrate average rotating surface (" MSR ") between outermost swing surface 208 and interior swing surface 210.When utilizing a straight bar test collimation of crossing over that backing roll 34 and 36 settles, the swing of roller will be introduced a height error, and its value is contact point and the average difference between the rotating surface MSR between this straight bar and the roller.Point 1 among Fig. 8 will make straight bar settle to such an extent that be higher than average rotating surface MSR, and turn to the top as fruit dot 2, and it will make straight bar be lower than average rotating surface MSR.Three rollers of because weigh in the span section all can both be swung, so people can see that the average rotating surface MSR of the roller 38 of weighing is not positioned at by the possibility on the plane of the average rotating surface MSR establishment of backing roll 34 and 36 very high.In addition, the average swing of each roller be difficult to be measured, because be difficult to touch mounted roller, has only the outward flange of roller can be for measurement usually.Simultaneously, roller (usually in radial zone of point 1) in measured zone may not show swing, and may swing occur elsewhere as at point 3 places.Then the problem that the people faced of any one span section of determining to weigh be average rotating surface MSR side direction with all three rollers be collimated to ± 0.001% margin tolerance in.This perturbation motion method that can utilize the present invention to illustrate is finished.
This disturbance device comprises that one is used for being used to detect and analyze the loaded span section of weighing at device, one that the belt stretch-draw of conveying belt 12 produces step change and the device of the response of step change and one is used for the device of roller height control in the given margin tolerance of weighing.For preferred embodiment, this disturbance device is included in any one that produces in the belt stretch-draw at least 10% Several Methods that changes.This can take the form of gaining in weight on straining pulley shown in Figure 1 212, perhaps utilize the belt tension adjuster of also representing in Fig. 1 214 to change the lengthwise position of batcher or conveyor guide wheel 24 simply.The pick-up unit of the preferred embodiment comprises that first and second force cells 40 that are connected on the roller two ends of weighing and one are connected in the processor of the roller height control that is used on first and second force cells to determine to weigh, and this height control can utilize a tiny pitch adjusting gear to finish.Simultaneously, the device that is used for analytical applications disturbance device result this end which end of roller requires height control and this adjustment whether must increase or reduce the roller of weighing of can determining to weigh.
Weigh during the plane when the load of roller 38 owing to coal or chain of weighing is drawn out by the average rotating surface MSR of backing roll 34 and 36 is determined, it is responsive that 54 pairs of belt tensions of the span of weighing section become.Usually, the weight that is evenly distributed in the loose unpacked material on the span section 54 of weighing causes the deflection D of the roller 38 of weighing and produces one recovers reacting force R, and the latter is making a concerted effort of belt tension T.Suppose that belt 12 is not sagging between two rollers, following analysis is a kind of simplification, but is enough to represent the error source that caused by belt tension.At first, for little deflection (θ≤10 °), tan θ approximates sin θ greatly, and wherein θ is the angle that is formed by deflection D, and P is the distance between deflection roll and the backing roll not.Because this geometric relationship, D/P is tan θ, and because deflection is little deflection, so θ approximates D/P greatly.But R is and the opposed side of θ, so R=Tsin θ or R=TD/P or R=2TD/P in fact, because two roll spacing sections are arranged in the plane of weighing.Reacting force R records as biased error by force cell 40, and the latter takes off the row form:
ε is the error ratio that R produces in the formula, and D and T make a concerted effort;
P is the roller square of span of weighing;
W is half the weight of span section of weighing;
ω is the weight gradient on the span section of weighing;
D is the displacement that the deflection of force cell under load produces;
R is again the reacting force that produces owing to D, and because it reduces W but negative.
Importantly to remember, reacting force be proportional to belt tension and be inversely proportional to the span roll spacing of weighing square.Therefore, the deflection D of force cell 40 produces an error that changes with the changing value of belt tension, so it is the error of repeatability or precision, this error is to be not easy to calibrate outside the span section of weighing of gravimetric feeder or conveyor.
Because the variation of belt tension is inevitably and causes reproducibility error usually, this kind susceptibility must be reduced to minimum.This can be by selecting a calibration weight that is equivalent to coal weight on the span to reach to each independent installation.This calibration weight value should select to be equivalent to the average density of user's coal.Therefore span and coal export cross section must be known or derive.Correct calibration weight is calculated as follows:
In the occasion of using two calibration weights, each weight is equivalent to half that calculates weight.
Then, the installation calibrating weight calculated above of utilization is finished disturbance.By the weigh height of roller 38 of the output adjustment of utilizing above-mentioned sensing and analytical equipment, the roller of weighing will be settled like this, make the roller of weighing when the carrier band coal is loaded that the susceptibility of minimum be arranged belt tension.
Calibration verification system of the present invention provides a kind of disturbance device and method, is used for the roller 38 of weighing is adjusted in the determined plane of average rotating surface by bolster (34,36) effectively.For preferred embodiment, this disturbance device comprises a pair of force cell 40 and processor that is connected on the force cell 40 that is connected on roller 38 two ends of weighing, the predetermined altitude of the roller 38 that is used to determine to weigh.Particularly, this processor is programmed the load of the independent flat homogenizing of each force cell 40 during being presented at conveying belt 12 under the instruction to rotate a complete circle.At first, weigh span 54 is loaded calibration weight or testing chains 50.Operate the average weight that batcher 10 obtains complete at least circle of conveying belt 12 rotations and record thus then.Secondly, increase belt tension at least 10% to 50% (200 to 300 pounds of standards).This can finish with many modes, comprises adjusting belt tightener 214 or increase an additional load on stretching pulley 212.Repeat first step then.If the load that obtains thus of any one force cell 40 output increases the increase of belt tension, so corresponding to the end adjustment De Taigao of the roller 38 of weighing of this force cell, vice versa.Utilize this disturbance device and method, this preferred embodiment can arrive the height control of the roller 38 of weighing in 0.0005 inch scope of its tram.
Claims (49)
1. the calibration verification system of a used for conveyer belt, this conveying has an entrance zone, threshold zone, weigh a span section and a discharging section, and this system comprises:
A conveying belt of settling around a pair of belt pulley, described conveying has the upper and lower that moves in opposite directions;
At least one first backing roll and one second backing roll are placed in below the described top and spaced apart, with the border of the span section of weighing that limits described conveying belt;
At least one roller of weighing, be placed in below the described top and described each other basically between first and second backing roll of plane collimation, described weigh roller and described first backing roll are isolated to limit first border of weighing the span roll spacing, and described weigh roller and described second backing roll are isolated limiting second border of weighing the span roll spacing, and the wherein said first span roll spacing of weighing equals the described second span roll spacing of weighing; And
A calibrated chain, comprise many chain rollers that utilize at least one chain link to be one another in series and to connect, described calibrated chain is placed in the described top of described conveying belt and the described span section of weighing by described conveying belt, described calibrated chain has corresponding to each chain pitch to distance between the adjacent described chain roller, described the chain pitch aliquot described first or second span roll spacing of weighing.
2. the described calibration verification system of claim 1 is characterized in that, described roller and described first and second backing roll of weighing is each other in the rectangle collimation and perpendicular to the direct of travel of described belt.
3. the described calibration verification system of claim 1, it is characterized in that, described conveying has one and is placed in described entrance zone, threshold zone and described weigh the first belt section between the span section and one are placed in described discharging section and the described second belt section of weighing between the span section, the wherein said first belt section has an entering angle and the described second belt section has a receding angle, no matter the load that described conveying belt bears is much, these two angles keep equating.
4. the described calibration verification system of claim 3 is characterized in that, described entering angle and described receding angle are that belt is flexible, the function of belt tension and load.
5. the described calibration verification system of claim 1, also comprise the perturbation analysis device that is connected on described at least one roller of weighing, be used for determining the optimum height of described at least one roller of weighing, described perturbation analysis device comprises the device that is used to analyze the device of the weigh load that extend through described weigh span section relevant with the belt tension of described conveying belt and is used to adjust described belt tension.
6. the described calibration verification system of claim 5 is characterized in that, described adjusting gear is adjusted described belt tension between two predetermined belt tensions.
7. the described calibration verification system of claim 5 is characterized in that, described perturbation analysis device is connected on the opposite ends of described at least one roller of weighing.
8. the described calibration verification system of claim 7, it is characterized in that, described perturbation analysis device comprises force cell and the processor that is connected on the described a pair of force cell on a pair of two ends that are connected in described at least one roller of weighing, and is used to measure the height error value of described at least one roller of weighing.
9. the described calibration verification system of claim 5 is characterized in that, described perturbation analysis device is connected in the device of the mechanical load of the described span section of weighing that is used to add up.
10. the described calibration verification system of claim 9, it is characterized in that, described perturbation analysis device comprises a force cell and the processor that is connected on the described force cell on the described adding up device that is connected in the described span section of weighing, and is used to measure the height error value of described at least one roller of weighing.
11. the described calibration verification system of claim 5 is characterized in that, the described analytical equipment of described perturbation analysis device can determine which end of described at least one roller of weighing need adjust the height.
12. the described calibration verification system of claim 1, it is characterized in that, described chain has first end, center section and the second end on entrance zone, threshold zone, the span of weighing section and the discharging section that is distributed in batcher respectively, and the weight of wherein said center section and spacing are controlled more carefully than the weight and the spacing of each described first and second end.
13. the calibration verification system that belt-type batcher or conveyor are used, this conveyor has an entrance zone, threshold zone, weigh a span section and a discharging section, and this system comprises:
A continuous conveyor of settling around a pair of belt pulley, described conveying has the upper and lower that moves in opposite directions;
At least one pair of backing roll, be placed in below the described top and spaced apart, with the border of the span section of weighing that limits described conveying belt, the described top of described conveying belt has one to be placed in described entrance zone, threshold zone and described weigh the first belt section between the span section and one are placed in described discharging section and the described second belt section of weighing between the span section;
At least one roller of weighing is placed in below the described top, makes described at least one roller and described backing roll plane collimation basically each other of weighing, and of described at least one roller of weighing is specific, and weigh roller and a pair of described backing roll is equidistant; And
A distinguishing chain apparatus is placed in above the above-mentioned top and the described span section of weighing by described conveying belt;
The wherein said first belt section has an entering angle and the described second belt section has a receding angle, no matter the load that described conveying belt bears is much, these two angles keep equating.
14. the described calibration verification system of claim 13 is characterized in that, described entering angle and described receding angle are that belt is flexible, the function of belt tension and load.
15. the described calibration verification system of claim 13 is characterized in that, described at least one weigh roller and described backing roll are each other in the rectangle collimation and the direction of advancing perpendicular to belt.
16. the described calibration verification system of claim 13, it is characterized in that, the described span section of weighing has the roll spacing of the span of weighing, described chain has a plurality of being placed in above the described top and the chain roller of the described span section of weighing by described conveying belt, and described chain has the chain pitch corresponding to distance between the adjacent chain roller, the aliquot described span of weighing of this chain pitch.
17. the described calibration verification system of claim 16 is characterized in that, the roll spacing of the described span of weighing remains on half of distance between the described border of the described span section of weighing.
18. the described calibration verification system of claim 13, also comprise the perturbation analysis device that is connected on described at least one roller of weighing, be used for determining the optimum height of described at least one roller of weighing, described perturbation analysis device comprises the device that is used to analyze the device of the weigh load that extend through described weigh span section relevant with the belt tension of described conveying belt and is used to adjust described belt tension.
19. the described calibration verification system of claim 18 is characterized in that, described adjusting gear is adjusted described belt tension between two predetermined belt tensions.
20. the described calibration verification system of claim 18 is characterized in that, described perturbation analysis device is connected on the opposite ends of described at least one roller of weighing.
21. the described calibration verification system of claim 20, it is characterized in that, described perturbation analysis device comprises force cell and the processor that is connected on the described a pair of force cell on a pair of two ends that are connected in described at least one roller of weighing, and is used to measure the height error value of described at least one roller of weighing.
22. the described calibration verification system of claim 18 is characterized in that, described perturbation analysis device is connected in the device of the mechanical load of the described span section of weighing that is used to add up.
23. the described calibration verification system of claim 22, it is characterized in that, described perturbation analysis device comprises a force cell and the processor that is connected on the described force cell on the described adding up device that is connected in the described span section of weighing, and is used to measure the height error value of described at least one roller of weighing.
24. right will be shown 18 described calibration verification systems, it is characterized in that, the described analytical equipment of described perturbation analysis device can determine which end of described at least one roller of weighing need adjust the height.
25. the described calibration verification system of claim 13, it is characterized in that, described chain has first end, center section and the second end on entrance zone, threshold zone, the span of weighing section and the discharging section that is distributed in batcher respectively, and the weight of wherein said center section and spacing are controlled more carefully than the weight and the spacing of each described first and second end.
26. the calibration verification system that belt-type batcher or conveyor are used, this conveyor has an entrance zone, threshold zone, weigh a span section and a discharging section, and this system comprises:
A continuous conveyor of settling around a pair of belt pulley, described conveying has the upper and lower that moves in opposite directions;
At least one pair of backing roll is placed in above the described top and spaced apart, and with the border of the span section of weighing that limits described conveying belt, the described span section of weighing has the span roll spacing of weighing;
At least one roller of weighing is placed in below the described top, makes described at least one roller and described backing roll plane collimation basically each other of weighing, and of described at least one roller of weighing is specific, and weigh roller and a pair of described backing roll is equidistant; And
Be connected in the perturbation analysis device on described at least one roller of weighing, be used for determining the optimum height of described at least one roller of weighing, described perturbation analysis device comprises the device that is used to analyze the device of the weigh load that extend through described weigh span section relevant with the belt tension of described conveying belt and is used to adjust described belt tension.
27. the described calibration verification system of claim 26 is characterized in that, described adjusting gear is adjusted described belt tension between two predetermined belt tensions.
28. the described calibration verification system of claim 26 is characterized in that, described perturbation analysis device is connected on the opposite ends of described at least one roller of weighing.
29. the described calibration verification system of claim 28, it is characterized in that, described perturbation analysis device comprises one to the force cell on the two ends that are connected in described at least one roller of weighing and a processor that is connected on the described a pair of force cell, is used to measure the height error value of described at least one roller of weighing.
30. the described calibration verification system of claim 26 is characterized in that, described perturbation analysis device is connected in the device of the mechanical load of the described span section of weighing that is used to add up.
31. the described calibration verification system of claim 30, it is characterized in that, described perturbation analysis device comprises a force cell and the processor that is connected on the described force cell on the described adding up device that is connected in the described span section of weighing, and is used to measure the height error value of described at least one roller of weighing.
32. the described calibration verification system of claim 26 is characterized in that, the described analytical equipment of described perturbation analysis device can determine which end of described at least one roller of weighing need adjust the height.
33. the described calibration verification system of claim 26 is characterized in that, the described span section of weighing has the roll spacing of the span of weighing, and the latter remains on the half-distance between the described border.
34. the described calibration verification system of claim 26 is characterized in that, described at least one weigh roller and described backing roll are each other in the rectangle collimation and the direction of advancing perpendicular to belt.
35. the described calibration verification system of claim 26, it is characterized in that, described chain has a plurality of being placed in above the described top and the chain roller of the described span section of weighing by described conveying belt, and described chain has the chain pitch corresponding to distance between the adjacent chain roller, the roll spacing of the aliquot described span of weighing of this chain pitch.
36. the described calibration verification system of claim 26, it is characterized in that, described conveying has one and is placed in described entrance zone, threshold zone and described weigh the first belt section between the span section and one are placed in described discharging section and the described second belt section of weighing between the span section, the wherein said first belt section has an entering angle and described second section has a receding angle, no matter the load that described conveying belt bears is much, these two angles keep equating.
37. the described calibration verification system of claim 36 is characterized in that, described entering angle and described receding angle are that belt is flexible, the function of belt tension and load.
38. the described calibration verification system of claim 26, it is characterized in that, described chain has first end, center section and the second end on entrance zone, threshold zone, the span of weighing section and the discharging section that is distributed in batcher respectively, and the weight of wherein said center section and spacing are controlled more carefully than the weight and the spacing of each described first and second end.
39. method that is used to check the align mode of belt-type batcher or conveyor, this batcher or conveyor have a continuous conveyor of settling around a pair of belt pulley, this batcher or conveyor have an entrance zone, threshold zone, weigh distance transregional section and a discharging section, wherein this span section of weighing has the span roll spacing of weighing, and this method comprises the following steps:
Select a distinguishing chain that a plurality of chain rollers are arranged, this distinguishing chain has the chain pitch corresponding to distance between the adjacent chain roller, the span roll spacing of weighing of the aliquot conveying belt of this chain pitch;
Distinguishing chain is placed on entrance zone, threshold zone, the span of weighing section and the discharging section of conveying belt, makes this distinguishing chain settle by this span section of weighing; And
Utilize this distinguishing chain simulative material load to check the align mode of belt-type batcher or conveyor.
40. the described method of claim 39, it is characterized in that, described conveying has one and is placed in entrance zone, threshold zone and described weigh the first belt section between the span section and one are placed in described discharging section and the described second belt section of weighing between the span section, and comprises the following steps:
Before the step of settling this distinguishing chain,, make the entering angle of the first belt section and the receding angle of the second belt section keep equating no matter the load that described conveying belt bears is much.
41. the described method of claim 40 is characterized in that, this entering angle and receding angle are that belt is flexible, the function of belt tension and load.
42. the described method of claim 39 is characterized in that, described belt-type batcher or conveyor comprise at least one pair of backing roll and at least one pair of roller of weighing that is placed in below the described span section of weighing, and comprise the following steps:
Described at least one roller of weighing is determined an optimum height, and described determining step is included in the load and adjust accordingly highly with the analysis load of weighing of weighing of analyzing that pass through relevant with the belt tension of conveying belt weigh that the span section extends before the step of check align mode.
43. the described method of claim 42 is characterized in that, the step of adjusting belt tension is included between two predetermined belt tensions adjusts belt tension.
44. the described method of claim 42 is characterized in that, the step of analyzing the load of weighing comprises measures the height error value at least one roller of weighing.
45. the described method of claim 42 is characterized in that, the step of analyzing the load of weighing comprises at least intactly rotates the circle mechanical load of span section of weighing that adds up to belt.
46. the described method of claim 42 is characterized in that, the step of analyzing the load of weighing comprises which end of determining this at least one roller of weighing need adjust height.
47. the described method of claim 46 is characterized in that, the step of calibrating belt-type batcher or conveyor after which end of determining this at least one roller of weighing need be adjusted the step of height.
48. the described method of claim 39, it is characterized in that, described distinguishing chain has the entrance zone, threshold zone that is distributed in described batcher respectively, first end, center section and the second end on described weigh span section and the described discharging section, wherein said center section has specific weight and spacing, and comprises the following steps:
Before the step of check align mode, more carefully control this specific weight and spacing than the weight and the spacing of each first the second end of control.
49. the described method of claim 39 is characterized in that, the step of described check calibration comprises that at least one circle to belt rotates the accurate known weight that the weight of this distinguishing chain relatively arrives this distinguishing chain.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97111134A CN1188232A (en) | 1996-05-09 | 1997-05-08 | System for checking calibration of gravimetric feeders and belt scales |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US647,117 | 1996-05-09 | ||
| CN97111134A CN1188232A (en) | 1996-05-09 | 1997-05-08 | System for checking calibration of gravimetric feeders and belt scales |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1188232A true CN1188232A (en) | 1998-07-22 |
Family
ID=5171669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97111134A Pending CN1188232A (en) | 1996-05-09 | 1997-05-08 | System for checking calibration of gravimetric feeders and belt scales |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1188232A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101006314B (en) * | 2005-04-13 | 2011-02-23 | 国际技术公司及国际技术公开有限公司 | Equipment for measurement and control of load material or scrap feeding into a furnace and relative method |
| CN102953755A (en) * | 2011-08-31 | 2013-03-06 | 淮南矿业(集团)有限责任公司 | Mine material loading control method and control device as well as mine material loading system |
| CN106959146A (en) * | 2016-01-12 | 2017-07-18 | 泉州装备制造研究所 | A kind of artificial stone's process building stones cloth evenness on-line measuring device |
| RU2759730C2 (en) * | 2020-03-17 | 2021-11-17 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Чувашский государственный аграрный университет" (ФГБОУ ВО Чувашский ГАУ) | Method for testing the feed dispenser for dosing accuracy |
-
1997
- 1997-05-08 CN CN97111134A patent/CN1188232A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101006314B (en) * | 2005-04-13 | 2011-02-23 | 国际技术公司及国际技术公开有限公司 | Equipment for measurement and control of load material or scrap feeding into a furnace and relative method |
| US9170050B2 (en) | 2005-04-13 | 2015-10-27 | Techint Compagnia Tecnica Internazionale S.P.A. | Equipment for measurement and control of load material or scrap feeding into a furnace and relative method |
| CN102953755A (en) * | 2011-08-31 | 2013-03-06 | 淮南矿业(集团)有限责任公司 | Mine material loading control method and control device as well as mine material loading system |
| CN106959146A (en) * | 2016-01-12 | 2017-07-18 | 泉州装备制造研究所 | A kind of artificial stone's process building stones cloth evenness on-line measuring device |
| CN106959146B (en) * | 2016-01-12 | 2022-11-22 | 泉州装备制造研究所 | Stone material distribution uniformity online detection device in artificial stone machining process |
| RU2759730C2 (en) * | 2020-03-17 | 2021-11-17 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Чувашский государственный аграрный университет" (ФГБОУ ВО Чувашский ГАУ) | Method for testing the feed dispenser for dosing accuracy |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5686653A (en) | System for checking the calibration of gravimetric feeders and belt scales | |
| AU681214B2 (en) | Conveyor friction scale | |
| US4682664A (en) | Load sensing systems for conveyor weigh scales | |
| US7331210B2 (en) | Conveyor weighbridge with built-in calibration weight | |
| EP2180300A1 (en) | High precision belt weighing array system for dispersed material | |
| US5296654A (en) | Universal belt scale | |
| CN101655388B (en) | On-line calibration primary-secondary belt balance and method | |
| CN1047070C (en) | Method of and apparatus for ascertaining mass of rod-shaped articles of tobacco processing industry | |
| KR20010053144A (en) | Chain conveyor | |
| CN102103006B (en) | Variable inclination angle rack conveyor belt scale and weighing method | |
| GB2165365A (en) | High-speed transporting and weighing machine | |
| CN102300787B (en) | Belt weighing system | |
| US5696354A (en) | Scale for weighing material transported along a movable conveyor | |
| CN114323217B (en) | High-precision belt scale | |
| CN1188232A (en) | System for checking calibration of gravimetric feeders and belt scales | |
| US4023668A (en) | In-line continuous checkweigher | |
| CN109238411B (en) | Double-fulcrum high-precision electronic belt scale | |
| EP0512115B1 (en) | Check weigher with aerodynamic correction | |
| CN107091677B (en) | Error compensation method and belt scale based on error compensation | |
| CN210268847U (en) | Electronic belt scale body with accurate measurement | |
| CN1029334C (en) | High-precision unilateral weighing method and device | |
| CN205373838U (en) | High accuracy suspension array belt weigher | |
| RU2814786C1 (en) | Belt scale calibration device | |
| SU1451554A1 (en) | Belt-conveyer weigher | |
| CN214251245U (en) | High-precision belt scale circulating dynamic experiment and training system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |