The present invention relates to a transport and weighing system comprising at least a first reciprocating tube or trough or other conveying means and a second reciprocating reference mass, which first or second reciprocating tube or trough or other conveying means are forced to oscillate in a mostly reciprocal movement by one ore more actuators, such as disclosed in EP 1349676 B1, filed by the same applicant.
The present invention further relates to a method for transport of goods by a vibrating transport system, which transport system comprises reciprocating movable conveying means and a reciprocating reference mass interconnected by spring means, which reciprocating conveying means and reciprocating reference mass are connected to a force generating apparatus, where goods in form of grains are loaded in the reciprocating conveying means, and the force generating apparatus is started, and the reciprocating conveying means and the load of grains starts to reciprocate within the conveying means.
U.S. Pat. No. 4,428,476 and U.S. Pat. No. 5,056,652 disclose a vibratory conveyor arranged so that the vibrations have a substantially greater horizontal than vertical movement. More particularly, the vertical acceleration of material carried by the conveyor is less than the acceleration of gravity and therefore the material conveyed does not physically leave the surface of the conveyor. The result is a smooth flow of material from one end of the trough to the other.
U.S. Pat. No. 5,836,204 concerns balanced vibration generator for resonance-amplified operation of a machine or equipment comprising at least one set of counter-oscillating masses, suspended in a spring system in which the resonance springs are helical springs which also support the masses. The generator comprises a built-in, balanced drive system. The generator is suspended in securing elements which comprise special, adjustable securing elements which are in engagement with the resonance springs and arranged in such a manner that the resonance springs, when turned around their longitudinal axes, can change spring lengths.
U.S. Pat. No. 6,705,459 concerns a vibratory feeder, which is minimized in an assembly including a base and an elongated, generally horizontal, feeder spaced from the base. A rotating mounted eccentric is placed on the feeder and is operable, when rotated, to impart vibration to the feeding surface of the feeder. The feeder is interconnected to the base by an interconnection that consists essentially of springs having first ends connected to the feeder and opposite ends connected to the base while being located on a generally horizontal axis.
JP 9005148 discloses a method and apparatus for supplying a specified amount of powder body within a specified accuracy in specified time length. The apparatus comprises a first vibration feeder having a base plate allowed to be vibrated and a second vibration feeder having a base plate which is placed on a weighing device and allowed to be vibrated. A powder body is fed unto the base plate with an overall bulk density being averaged and the powder body is delivered to a base plate from the base plate so that a part of the bulk density is concentrated partially while the quantity of the powder body is weighed with the base plate at rest. The amount of the powder body to be supplied to a container from the base plate is charged hourly.
It is the object of the pending application to describe a system and a method for vibration transport of goods and to determine the mass of goods delivered by the transport system.
The object can be fulfilled by a system as described in the preamble to the claim 1 and further modified if the transport system is at least partly or full carried by one or more load cells, which load cells is connected to a computer system, which computer system performs a calculation of the mass of transported goods.
Hereby can be achieved, that the computer system can deliver a continuous measurement of the mass of the goods which are transported. The weight of the goods may be important e.g. in process calculations and for quality control and documentation in process industry. For many purposes, it is very important to deliver the correct defined mass of goods transported in an automatic conveyor system. It is well-known by belt-conveyor transportation systems to calculate the weight of the goods delivered by the belt. By vibration transportation this has previously been impossible because the vibration has negative influence of the result received from load cells. A special computer system is needed to overcome noise in electric signal generated by load cells. The computer system can perform digital filtration of received signals, and as such the computer system can give at least an average measurement over a short period of time. Hereby, a vibration transport system may work just like a standard moving trough which performs combined transport and weighing system. The transport system described in the pending application has an advantage in that the transporting conveying means can be relatively long. Another advantage is that transportation is performed inside a conveying means in the form of a tube instead of a moving trough. The transport system as described in the pending application uses a second reciprocating reference mass. The oscillating system as such comprises both the reciprocating conveying means and the reciprocating reference mass interconnected by springs which forms an oscillating system which is in operation with a resonance frequency. Operating in the resonance frequency area will limit the necessary forces which have to be added to the oscillating system so that relatively weak motors can be used to drive the oscillating system e.g. by an eccentric exciter connected to a motor and to a connection spring. Hereby, it can be achieved that only a low amount of energy is necessary for transporting goods in the reciprocating conveying means.
A feed hopper can comprise a pre-feeder, which can be connected to the inlet to the reciprocating tube or trough, which pre feeder can generate a homogenous flow of material into the reciprocating tube or trough. By using a pre-feeder at the inlet to the reciprocating tube or trough, it can be achieved that a relatively homogenous layer of goods or grain is delivered into the reciprocating tube or trough. By letting the pre-feeder comprise a vibrating cone near its outlet, it is possible that the material will be prevented from sticking in the pre-feeder. Preferably the pre-feeder is carried by itself so that the pre-feeder is mechanically independent of the reciprocating tube or trough.
The vertical level of goods or grain can be measured by at least one optical distance measurement system. By measuring the vertical level of the material in the form of grain or goods conveyed in the reciprocating tube or trough, it is possible to indicate the actual volume that is being conveyed. Hereby overfilling of the reciprocating tube or trough can be prevented. By using feedback routine from the measurement of the vertical level it is possible, by the control of the pre-feeder to achieve a very homogenous layer of material in the reciprocating tube or trough.
At least a first accelerometer can be connected to the reciprocating tube or trough. By measuring the actual acceleration existing in the reciprocating tube or trough, it is possible to together with know-how about the material conveyed and the vertical level measurement to measure the mass flowing through the reciprocating tube or trough. Hereby it can be achieved that the very precise mass flow can be delivered at an outlet, because the pre-feeder can be adjusted for controlling the mass flow.
The actuator can be formed as one or more linear actuators which number of actuators can increase with longer transport systems, which linear actuators are connected to the first reciprocating tube or trough and to the second reciprocating reference mass. The reciprocating movement of the tube or trough and the counter movement of the reference mass can be achieved in various ways. One possibility is to use a rotating electric motor and by use of a crankshaft mechanism to achieve the reciprocation. In an alternative embodiment of the invention, linear actuators could be connected between the reference mass and the tube or trough so that the actual vibration is generated exactly in the correct direction by for example four linear actuators. These linear actuators could be electric, may be formed as magnetic plungers. By alternative embodiments it is also possible to use hydraulic or pneumatic actuators for achieving the reciprocating movement.
The outlet of the reciprocating tube or trough can deliver transported material into a weighing bucket. By connecting a weighing bucket to the outlet of the reciprocating tube or trough, it is possible to perform an automatic control of the amount of material being conveyed. The weighing bucket can be used for a daily calibration or it can be coupled continuously in order to obtain a very precise indication of the mass of the material conveyed.
The actuators can be controlled by a computer system, which computer system receives information from at least the weighing cells and from the accelerometer, which computer system can calculate the weight of the transported material. The computer system can be used for controlling the actuators and controlling the pre-feeder and also receiving feedback from the weighing bucket. Probably, input will also come from the optical level of detection, so that the computer system, based on data from accelerometer and the optical vertical measurement can calculate the mass flow to the vibrating tube or trough. Depending on the material being conveyed, it is possible to change both the frequency of the vibration and may be also change the vibrating amplitude. In most situations, the vibration frequency is to be very close to the natural oscillating frequency of the mechanical system of the tube or trough and the counter oscillating reference mass. Therefore the influence of the oscillating frequency is rather limited, but depending on the mass or material being conveyed it can be necessary to slightly change the frequency. By using the computer system, it is possible to perform a control of a system so that the system can operate fully automatically.
The second reference mass can be formed as one or more second conveying means, which first and second conveying means are forced into opposite reciprocating. Hereby can the first and second conveying means form two parallel operating transport units. In an alternative embodiment can two conveying means operate serial and thereby forming a very long conveying unit.
The first and second reciprocating conveying means or reference mass can be connected by spring means. Herby can the first and second reciprocating conveying means or reference mass form a resonance oscillating system.
The transport system can be carried by a support frame. Hereby can be achieved that the support frame can receive and reduce oscillation generated by the reciprocating conveying means or reference mass. This can lead to an effective reduction of vibrations transmitted to the weight cell.
The support frame is carried in at least one hanger, which hanger carries the support frame by at least one flexible band. Hereby it can be achieved that only small vibrations will be transmitted to the floor below the transport system. At first only small vibrations are transmitted to the support frame, and when the support frame is hanging in e.g. flexible bands in the hanger, only very limited vibrations are to be delivered towards the floor.
The hanger is carried by at least one load cell. By placing load cells under the hanger, it is possible to measure the weight of goods filled into the reciprocating conveying means. Measuring the weight at least one point where vibrations are reduced gives a more accurate measurement. Therefore, the necessary filtration in a digital filter in a computer system can be reduced. If more hangers are necessary for supporting e.g. the long reciprocating conveying means and the reciprocating conveying means reference mass, it is possible to place the load cells under each of the hangers so that the computer system will receive a number of load cell information when the system is in operation. Hereby, it can be indicated approximately where in the conveying means the concentration of goods is the highest and where it is the lowest. If e.g. a conveying means is full, there is no reason for adding more goods into the conveying means.
The spring means can comprise a first and a second row of springs, which rows of springs are placed at the side and fastened to the side of both the reciprocating conveying means and the reciprocating reference mass. By placing the springs by the side of the reciprocating conveying means and by the side of the reciprocating reference mass, the springs are out of the way allowing both the conveying means and the reference mass to be placed relatively close to each other. In that way, a relatively low transportation apparatus can be performed. By placing the springs at both sides of the reciprocating conveying means and the reciprocating reference mass, the oscillation can be more or less controlled by the springs themselves. Consequently, no further guiding means are necessary to keep the oscillating components in place.
The spring means can be supported by flexible spring supports, which spring supports are fixed to the support frame. The reciprocating conveying means and the reciprocating reference mass need to be supported in order to have freedom of movement when the system is in operation. Therefore, support is placed at the reference frame where the springs are supported at both ends. Thereby, both the reciprocating conveying means and the reciprocating reference mass are carried by flexible means allowing for reciprocating movement with only little friction.
The reciprocating conveying means and the reciprocating reference mass can be reciprocating in both horizontal and vertical direction, which horizontal reciprocation is larger than the vertical reciprocation. By letting the reciprocation take place in a slightly upward direction, it is possible by the reciprocation to let the goods more or less be lifted upwards in a period when the conveying means is moved backwards. But in order to have an upward acceleration, the reciprocation must take place with a degree of approximately 30 degrees above the horizontal line. In that way sufficient energy is delivered to the particles of the goods so they may not be flying in the conveying means, but they are losing most of their weight when the conveying means moves backwards, and as such the grain of goods are moved forwards. The bigger the horizontal movement, the faster the transportation will be performed. Therefore, the angle of the reciprocation could be adjusted independently of the weight of the grains of the goods which are transported.
The object can also be fulfilled by a method as described in the preamble to claim 7 and further modified if the method performs measuring the load of the goods transported in the reciprocating movable conveying means by at one or more load cells, transmit measured values to a computer system, where the computer system calculates the amount of goods transported in the conveying means.
By the method, a highly efficient transport system can be achieved which is not only able to transport the goods but also to measure the weight of the goods which are delivered. Hereby, a vibration transportation system can perform the same job as a transport trough. But the advantage is that transportation takes place in a closed conveying means instead of on an open trough. The reciprocating conveying means and the reciprocating reference mass can be very long; so long transportation can be performed in a closed conveying means. The length of the transport system only depends on the number of support springs necessary for carrying the reciprocating conveying means and the reciprocating reference mass. Systems longer than 10 metres would be possible.
At
In operation the oscillating forces are generated by the linear actuators 110 and 112 for starting an oscillation between the tube or trough 106 and the reference mass 108. These linear actuators are controlled by the computer system 124 which by communication lines 125 and 127 is communicating with the linear actuators 110 and 112. Since the actuators 110 and 112 have a feedback system the actual position will always be available in the computer. Therefore, a very precise mostly sinus formed oscillation could be achieved. Both the frequency and the amplitude of the oscillation can be controlled by the computer system. The computer system therefore knows the actual acceleration that is applied to the oscillating tube 106 and therefore together with information from weighing cells 118 and 120, it is possible to calculate the mass flow through the tube or trough 106.
By the invention as described in the figures described above, it is possible by this vibration transport system not only to transport goods, but also to perform continuous weighing of the goods that are delivered. Weighing cells could be placed in different ways below the frame, and in fact the frame could be developed in a way where only a single weighing cell is able to perform the complete weighing of the product which is delivered. Therefore the pending application is not limited to any described placement of the weighing cells.
Carrying the vibration transport system at the centre for gravity forces acting at the vibration transport system will increase the accuracy of a measuring weigh cell placed at the opposite end of the vibration transport system because only the weight of the transported goods are to be measured at the weight cell.
By the system shown at
Number | Date | Country | Kind |
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2010 70480 | Nov 2010 | DK | national |
2011 70166 | Apr 2011 | PA | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DK2011/050428 | 11/11/2011 | WO | 00 | 6/24/2013 |