Technical Field

A system and a method to reliably verify conveyance of material in terms of flow and its evenness inside a screw conveyor is disclosed.

Background

A screw conveyor, also called auger conveyor, is a mechanism that uses a rotating helical screw blade, called a "flighting", usually within a tube, to move liquid or granular materials. They are used in many bulk handling industries. Screw conveyors in modern industry are often used horizontally or at a slight incline as an efficient way to move semi-solid materials, including food waste, wood chips, aggregates, cereal grains, animal feed, boiler ash, meat, and bone meal, municipal solid waste, and many others. The first type of screw conveyor was the Archimedes' screw, used since ancient times to pump irrigation water.

They usually consist of a trough or tube containing either a spiral blade coiled around a shaft, driven at one end and held at the other, or a "shaftless spiral", driven at one end and free at the other. The rate of volume transfer is proportional to the rotation rate of the shaft. In industrial control applications, the device is often used as a variable rate feeder by varying the rotation rate of the shaft to deliver a measured rate or quantity of material into a process.

Screw conveyors can be operated with the flow of material inclined upward. When space allows, this is a very economical method of elevating and conveying. As the angle of inclination increases, the capacity of a given unit rapidly decreases.

The rotating part of the conveyor is sometimes called simply an auger.

A number of inventions offer solutions to have the duty done.

CN110817299 discloses a material conveying device with a screw shaft spreading mechanism comprises a platform used for providing the functions of material spreading and material propelling. According to the platform, at least two or more sets of grid bars are spaced and stacked to be spread to form a bar stacking propelling type material conveying platform; the adjacent grid bars on the same set are spaced by gaskets, the thickness of the gaskets is larger than that of the grid bars of another set of grid bars, and therefore ventilation gaps are formed; the screw shaft spreading mechanism is arranged above the starting end of the platform; the screw shaft spreading mechanism comprises a screw shaft; and the screw shaft is transversely arranged above the starting end of the platform and is provided with a feeding end and a tail end, by means of rotating motion of the screw shaft, materials are spread to the tail end from the feeding end of the screw shaft, and the materials are spread to the position, located at the bottom of the screw shaft, of the platform. According to the material conveying device, no crushing or pelleting or bar making machine needs to be arranged at a feeding opening of drying equipment, the equipment input is reduced, and cost is saved.

JP S 6077034 discloses a device to carry out objects stored in a hopper smoothly and effectively without involving occurrence of bridging phenomena by incorporating a carryout screw conveyor. For this, a carry-out screw conveyor is installed at the center of the bottom of hopper A, and on both sides of this conveyor, No.l-No.4 scratching screw conveyors scratching screw conveyors are arranged in such a way parallelly to each other and symmetrically about the carry-out screw conveyor. The carry-out screw conveyor is in such a construction that a screw is borne by a shaft installed above the bottom part of the bottom wall oriented towards both end walls, wherein one of the ends of said shaft protrudes at one of the end walls and a rotatable gear with respect to the shaft is furnished sprocket is fixed, which is coupled with another sprocket to be driven by a carry-out motor through a chain.

The utility model KR.20130004795 relates to a trough of a screw conveyor, and more particularly, to facilitate cleaning and management of the screw conveyor used to transport and discharge various bacteria present in the wastewater passing through the waterway to the outside, and to replace the liner and It relates to a trough of a screw conveyor that can facilitate maintenance work. The present invention is made in a U shape, the lower trough is formed in the lower part, the upper trough is formed parallel to the upper part of the lower trough, and the screw is A trough body made of a plurality to be inserted and installed; It is composed of a plurality of hinges installed to connect and fix the lower trough and the upper trough of the trough body It is characterized. As such, the trough of the screw conveyor of the present invention has the advantage of being able to work easily and quickly when maintenance of the screw conveyor and replacing the liner, and the effect of preventing safety accidents by working quickly and safely with a small number of workers There is. In addition, the present invention enables quick and easy maintenance during maintenance of a screw conveyor, so that workability is improved, work efficiency is excellent, and maintenance can be performed at low cost.

KR.200428314 discloses a Screw conveyor for Sludge Feed of Underwater application.

While the prior art approaches may be satisfactory in some regards, they have certain shortcomings and disadvantages. Nowadays, such screw conveyors generally are used in an unsupervised method, invisible for an operator or in an environment that may be inconvenient to a possible operator. It can therefore be uncertain whether the material to be conveyed is really conveyed or to the contrary, the screw conveyor keeps rotating although no material is really transported.

A screw conveyor may convey material with a substantially even flow, depended on the turning speed of its conveying screw. In case of incidents, like lumpy or bridging material inside the feeding hopper or mechanical failure of the screw drive, the even flow of material can get impaired or even discontinued. Hence, at applications, in which an unimpeded flow of conveyed material is important in terms of functional safety, the flow can be monitored.

Using mechanic or contactless sensorics at the conveyor's outlet can be seen as another possibility of today's state of the art. But it can be considered that contactless sensors like radar- or ultra-sonic sensors may not be reliable for precise measuring of slow material flows like they can occur in screw conveyors. The same can apply to the use of electrostatic sensors. For them, too, the flow of material can be too slow to be reliably detected. Mechanic sensors, like paddle wheels or contact switches, can eventually not detect changes in material flow reliably and can require suitable conditions like space and accessibility for installation.

Summary

It is therefore an object of the invention to overcome or at least alleviate the shortcomings and disadvantages of the prior art. More particularly, it is an object of the present invention to provide an automated, unsupervised way of registration whether the conveyed material is actually transported.

At conventional screw conveyors, a rotary sensor, can be located at the other screw shaft end opposite to the screw drive, may observe the rotation of the screw shaft. However, this detects mechanic failures of the screw drive only and is not possible to install at each application of screw conveyors. Detecting disturbances in material flow can be done by measuring the decrease of weight at feeding bin including the screw conveyor. But in the very most applications this is not possible since the screw conveyor is fully connected to the surrounding system. The detection of the increase in weight of the conveyed material after the screw conveyor would be a similar approach which, due to the high technical effort, can also only be implemented in very few cases.

In contrast to a conventional screw conveyor, in which one or more driven screw shafts are located (motorized drive), an additional non-driven screw shaft (hereinafter referred to as passive screw shaft) is installed in the novel screw conveyor. This can be located downstream of the driven screw shaft and upstream of the outlet of the medium to be conveyed from the screw conveyor, as seen in the direction of flow. Its shape is such that it is rotated by the medium conveyed by the driven screw shaft. The axis of the passive screw shaft, like that of the driven screw shaft, is parallel to the direction of flow of the conveyed medium. The passive screw shaft axis can be bearded coaxially together with the driven screw shaft or independently to the opposite end of the screw conveyor. The same applies to the rotary sensor, which detects the rotation of the passive screw shaft axis.

Opposite flank angles (pitch) of the two screw shafts ensure that they rotate in opposite directions to each other. The opposite direction of rotation excludes any possible positive locking between the shafts.

The rotary motion of the passive screw shaft serves as evidence during operation of the screw conveyor that a medium is being conveyed through the screw conveyor. Furthermore, drawing conclusions about the evenness in flow of the conveyed material can be done by monitoring the difference in turning speed between driven and passive screw shaft. This means for instance, that emergent critical properties, like cohesiveness, which cause uncontrolled flow rates inside the feeding hopper due to material bridging, can already get detected before the material flow comes to a complete standstill. In order to compensate for fluctuations in the material flow, it is also conceivable, to use the speed signal of the passive screw shaft as a manipulated variable for the control-driven screw shaft.

Another advantage of the novel system is, that its installation does not limit the screw conveyors application in terms of temperature or chemical composition of conveyed material. Only in terms of space, a respective axial extension is necessary. In case of a coaxial execution, the rotating movement is tangible from same side, as the drive is located. This solution doesn' t limit the application of the novel screw conveyor in terms of accessibility, in comparison to conventional screw conveyors.

The invention solves the technical problem that has existed up to now in the field of "functional safety", the simple verification of material conveying, by means of a closed screw conveyor into a closed inaccessible system. In this term, one conceivable application is the feeding of combustible material into a burner unit, in which the feed ratio between combustible material and pure oxygen must be constantly monitored in order to avoid oxygen enriched atmospheres downstream the burning process. In case of a lack of combustible material, the sensor triggers an alarm and stop the feed of oxygen consequently.

Another field of application is seen in mixing of bulk material. Due to the technical inadequacies of conventional conveyors, like described above, bulk materials are usually mixed batchwise with previously weighted batches of components. By feeding all components with multiple novel conveyors in parallel, a continuous mix of material can be ensured inside the following system by stopping or slowing down the feed of all conveyors according to the lack of material in one of them. A material flow generated in this way makes batch-wise weighing of each individual component superfluous and strongly simplifies the mixing process.

A conveyor can be configured to convey material, wherein a passive-rotator is at least partly arranged in a material path. This means, that a rotatably arranged axis with a screw shaped structure can be, similarly according to an Archimedes screw, transport material. Such material can be liquid, but also solid material, like wood chips, sand, pebbles, sludge, slurry, and other material, or a combination or an emulsive material.

Within the path of the conveyed material, a second rotator can be applied that may be configured to rotate freely, only or preferably driven by the conveyed material.

While a conveyed material is propelled by a screw conveyor, in an unattended environment, the material may block the flow of the material, or, the replenishment of material may cease. This may have the reason that no further material is there to be transported. Another reason can be that the intake of the screw conveyor may experience an agglutination or clumping of the material, which may lead to the material flow reduce or even stop. Therefore, the passive-rotator may comprise a helical thread. The thread will usually comprise a fixed helical thread like a widely known Archimedean screw. However, the passive screw may also comprise a variable (increasing or decreasing) slope. In a further embodiment, instead or in combination with a screw shaped passive-rotator, an impeller may deliver a feedback whether a material flow occurs or not. In an environment, where a generally known material is conveyed by the screw conveyor, the rotational speed of the passive-rotator may be determined by calculating a theoretical number of rotations per time-slot. The detected rotational speed of the passive-rotator may represent the real material flow quantitative and/or as a yes (=flow) or no (=no flow) value. Also, the efficiency of the conveying rate of the screw conveyor may be determined, if the value of the measured rotational speed of the passive-rotator differs from the theoretically estimated value.

The passive-rotator may contribute its motion information to a sensor that detects the fact and/or the speed of a rotation, the sensor may be a rotary sensor.

The rotary sensor may be configured to be driven by the conveyed material; to prevent a short-circuiting of the actively driven screw of the screw-conveyor with the passiverotator, the passive-rotator may be configured to be driven in a counter-sense to the rotational orientation of the screw of the screw-conveyor.

The passive-rotator may comprise an axis that can be oriented longitudinally. In an embodiment, the longitudinal axis may align with an axis of the power-driven screw of the screw conveyor.

The longitudinal axis of the passive rotator may further be formed as an axle, wherein the axle may convey the rotational motion of the passive-rotator to a sensor that is described above and below.

The second axis of the screw of the screw conveyor may be identical with the longitudinal axis of the passive-rotator.

The passive-rotator may by its rotation provide a signal to a control unit that may display and/or control the rotation. The signal that represents the motion of the passive-rotator may be converted into an electrical signal.

The electrical signal may represent the fact whether the passive-rotator rotates at all, or determines the speed of the rotation, represented, for instance, in rotations per minute (rpm). Also, the sense of the rotation may be detected.

The passive-rotator can be configured to rotate independently from the rotation of the screw of the screw conveyor, independently mainly rotational-sense wise, but also from the rotational speed of the power-driven screw of the screw conveyor. The passive-rotator can comprise opposite flank angles than the screw of the screw conveyor. This embodiment may be selected to make sure that the both screws — rotate in opposite sense when material flows and propels the passive-rotator.

Although the flank angles of the both screws, the machine-powered screw of the screw conveyor versus the screw of the passive rotator, can be evenly dimensioned, also differing flank angles are disclosed. Even variable flank angles are possible, be they becoming narrower or wider.

The material to be conveyed by the screw conveyor, may propel the passive-rotator by passing through the gaps of the passive-rotator. Once the material passes through the structure of the screw-conveyor, the passive-screw may be forcedly rotated.

The passive-rotator may be configured to be moved, i.e. rotated, by the material with a tenacity of more than q ~ 100 mPa*s.

The passive rotator may be configured to be moved, i.e. rotated, by the material with a shearing resistance of below 5 kNnr ² .

The passive-rotator to be rotated by a through-passing material, may be configured to experience a kinetic friction coefficient p of less than the torque force provided by the material.

The torque, resulting from kinetic friction between the screw of the screw conveyor and the screw of the passive - rotator, can be less than the torque provided by the conveyed material.

A first rotational speed of the screw of the screw conveyor may be less than 100 rpm, preferably less than 60 rpm and more than 2 rpm, preferably more than 10 rpm.

A second rotational speed of the passive-rotator may be configured to have more than 10% of the first rotational speed, preferably more than 30% of the first rotational speed and more preferably more than 50% of the first rotational speed. In some embodiments, the slip or skid of the passive-rotator may be difficult to predict and may need calibration, if the amount of the transported material is relevant. In some cases, it may be sufficient to control just the fact, whether a material flow takes place or not.

The screw of the screw conveyor and an inverted pitch of the passive-rotator may be substantially equal, preferably the pitch of the screw of the screw conveyor and the inverted pitch of the passive-rotator differ less than 90%, preferably below 70%, most preferably below 50%. The screw of the screw conveyor may comprise a self-lubricating material, for instance, brass, polyester, PTFE, Meta-Aramid, Graphite, Moly (MoS ₂ ), iron, steel, stainless steel, aluminum, ceramic and other material.

The screw of the screw conveyor may comprise metallic material like iron, steel, stainless steel, brass, aluminum and other material, that may also resist chemical stress caused by the transported material.

Alternatively, or additionally, a variety of plastic material may be comprised in or on the screw of the conveyor. Such plastic material, may be one or a combination of Polyethylen (PE), Polypropylen (PP), Polyvinylchlorid (PVC), Polystyrol (PS), Polyethylenterephtalat (PET) or Polycarbonat (PC).

The passive-rotator may comprise any of the material suitable for the screw of the screw conveyor, and may further comprise at least one of carbon, composite material, ceramics or sintered material.

The passive-rotator may comprise a metallic material, preferably at least one of iron, steel, stainless steel, brass or aluminum.

The screw of the screw conveyor may comprise plastic material, preferably at least one of Polyethylen (PE), Polypropylen (PP), Polyvinylchlorid (PVC), Polystyrol (PS), Polyethylenterephtalat (PET) or Polycarbonat (PC).

The screw conveyor may also comprise at least one control unit configured to determine the estimated mass transport of a material against an estimated mass transport based on the speed of the passive-rotor.

The screw conveyor may further comprise at least one control unit configured to compare the volume of a material against an estimated volume transport based on the speed of the passive-rotor.

Further, the screw conveyor may be fitted with a sensor- and control unit. The sensor(s) may contribute values representing physical and/or chemical properties of the screw conveyor, the conveyed material and the corresponding surroundings.

Physical properties of the screw conveyor can be the rotational speed of the screw, the orientation of the rotation, the temperature of a bearing, humidity in the housing of a screw conveyor and others.

Further, the values derived from the sensors or input data may be fed into a control unit that can supervise the functionality of the screw conveyor. The rotational speed of the screw for instance, may be taken to calculate the amount of conveyed material. The control may further compare the measured values against values that have been preset and initiate a feedback if the measured values differ from the pre-set values more than a tolerance rate.

In general, the control unit may be configured to compute at least one calculation.

Further, the control unit may determine any of the sense of a rotation of a passiverotator, the speed of the rotation of the passive-rotator, the speed of the rotation of the passive-rotator over time, a relation of the speed of a screw of a screw conveyor and the speed of the rotation of the passive-rotator.

Further, the control unit may be configured to detect an oscillation of the screw of the screw conveyor and/or the passive-rotator.

The control unit may further detect the power consumption of a motor, compare the estimated mass transport of a material against an estimated mass transport based on the speed of the passive-rotor.

Also, the volume of the volume of a material against an estimated volume transport based on the speed of the passive-rotor may be detected and/or calculated.

The control unit may further initiate measures under certain conditions. As an example, if the power consumption of the motor rises over a defined limit (out-of-boundary value), the control unit may stop the screw conveyor and/ or initiate an alarm, optical, acoustical and/ or by wired or wireless communication to a superior instance.

A method is disclosed to sense material flow by the step of determining the material flow that propels a passive-rotator.

The method may further comprise the step of determining the direction and a first rotational speed of the passive-rotator.

The method may further comprise the step of transferring the direction and the first rotational speed of the passive-rotator to a control unit.

The method may further comprise the step of the control unit receiving a second rotational speed of a motor.

The method can further comprise the step of determining a quantity of the material flow. Embodiments

Whenever a relative term, such as "about", "substantially" or "approximately" is used in this specification, such a term should also be construed to also include the exact term. That is, e.g., "substantially straight" should be construed to also include "(exactly) straight".

Whenever steps were recited in the above or also in the appended claims, it should be noted that the order in which the steps are recited in this text may be accidental. That is, unless otherwise specified or unless clear to the skilled person, the order in which steps are recited may be accidental. That is, when the present document states, e.g., that a method comprises steps (A) and (B), this does not necessarily mean that step (A) precedes step (B), but it is also possible that step (A) is performed (at least partly) simultaneously with step (B) or that step (B) precedes step (A). Furthermore, when a step (X) is said to precede another step (Z), this does not imply that there is no step between steps (X) and (Z). That is, step (X) preceding step (Z) encompasses the situation that step (X) is performed directly before step (Z), but also the situation that (X) is performed before one or more steps (Yl), ..., followed by step (Z). Corresponding considerations apply when terms like "after" or "before" are used.

While in the above, a preferred embodiment has been described with reference to the accompanying drawings, the skilled person will understand that this embodiment was provided for illustrative purpose only and should by no means be construed to limit the scope of the present invention, which is defined by the claims.

In the claims, the terms "comprises/comprising", "including", "having", and "contain" and their variations should be understood as meaning "including but not limited to", and are not intended to exclude other components. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality.

Whenever steps were recited in the above or also in the appended claims, it should be noted that the order in which the steps are recited in this text may be the preferred order, but it may not be mandatory to carry out the steps in the recited order. That is, unless otherwise specified or unless clear to the skilled person, the order in which steps are recited may not be mandatory. That is, when the present document states, e.g., that a method comprises steps (A) and (B), this does not necessarily mean that step (A) precedes step (B), but it is also possible that step (A) is performed (at least partly) simultaneously with step (B) or that step (B) precedes step (A). Furthermore, when a step (X) is said to precede another step (Z), this does not imply that there is no step between steps (X) and (Z). That is, step (X) preceding step (Z) encompasses the situation that step (X) is performed directly before step (Z), but also the situation that (X) is performed before one or more steps (Yl), ..., followed by step (Z). Corresponding considerations apply when terms like "after" or "before" are used.

It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention can be made while still falling within scope of the invention. Features disclosed in the specification, unless stated otherwise, can be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed represents one example of a generic series of equivalent or similar features.

Use of exemplary language, such as "for instance", "such as", "for example" and the like, is merely intended to better illustrate the invention and does not indicate a limitation on the scope of the invention unless so claimed. Any steps described in the specification may be performed in any order or simultaneously, unless the context clearly indicates otherwise.

All of the features and/or steps disclosed in the specification can be combined in any combination, except for combinations where at least some of the features and/or steps are mutually exclusive. In particular, preferred features of the invention are applicable to all aspects of the invention and may be used in any combination.

Reference numbers and letters appearing between parentheses in the claims, identifying features described in the embodiments and illustrated in the accompanying drawings, are provided as an aid to the reader as an exemplification of the matter claimed. The inclusion of such reference numbers and letters is not to be interpreted as placing any limitations on the scope of the claims.

The expression "axis" is a real or imaginary straight line going through the center of an object that is arranged to spin, or a line that divides a symmetrical shape into two equal halves.

An "axle" is a bar or pipe connected to the center of a circular that allows or causes it to turn. The expression "emulsive material" means a material similar to an emulsion that may be transported like a liquid or a semi-solid material.

Below is a list of system embodiments. Those will be indicated with a letter "S". Whenever such embodiments are referred to, this will be done by referring to "S" embodiments.

51. A conveyor (1) configured to convey material, wherein a passive-rotator (10) is at least partly arranged in a material path.

52. The conveyor (1) according to the preceding embodiment wherein the conveyor (1) comprises a screw to form a screw conveyor (1).

53. The conveyor (1) according to the preceding embodiment, wherein a passiverotator (10) is configured to be driven by a material flow.

54. The conveyor (1) configured to convey material, wherein the passive-rotator (10) comprises a helical thread, preferably a fixed helical thread, such as an Archimedean screw.

55. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) comprises an impeller.

56. The conveyor (1) according to any of the preceding embodiments, wherein a sensor (S) is configured to the passive-rotator (10) and is configured to detect material flow.

57. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) comprises a rotary sensor (s).

58. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) is configured to rotate in counter-sense to a screw of the conveyor (1).

59. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) comprises a longitudinal axis (20).

510. The screw conveyor (1) according to any of the preceding embodiments, wherein the longitudinal axis (20) is formed as an axle (20).

511. The screw conveyor (1) according to any of the preceding embodiments, wherein a second axis of the screw conveyor (1) and the longitudinal axis (20) form an identical axis (20).

512. The screw conveyor (1) according to any of the preceding embodiments, wherein the sensor (S) is configured to provide an electrical signal. The conveyor (1) according to any of the preceding embodiments, wherein the electrical signal comprises at least one of the rotational speed of the passive-rotator (10); or the rotational sense of the passive-rotator (10). The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) is configured to rotate independently from a rotation of the screw of the screw conveyor (1). The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) comprises opposite flank angles than the screw of the screw conveyor (1). The conveyor (1) according to any of the preceding embodiments, wherein the flank angles of the passive-rotator (10) is different from the flank angle of the screw conveyor (1). The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) is configured to be driven by the material. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) is configured to be propelled by the material with a tenacity of more than q ~ 100 mPa*s. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) is configured to be propelled by the material with a shearing resistance of below 5 kNm’ ² . The conveyor (1) according to any of the preceding embodiments, wherein a kinetic friction coefficient p of the passive rotator (10) is less than the torque provided by the material. The conveyor (1) according to any of the preceding embodiments, wherein the torque, resulting from kinetic friction between the screw of the screw conveyor and the screw of the passive - rotator (10), is less than the torque provided by the conveyed material. The conveyor (1) according to any of the preceding embodiments, wherein a first rotational speed of the screw of the screw conveyor (1) is less than 100 rpm, preferably less than 60 rpm and more than 2 rpm, preferably more than 10 rpm. The conveyor (1) according to any of the preceding embodiments, wherein a second rotational speed of the passive-rotator (10) is configured to have more than 10% of the first rotational speed, preferably more than 30% of the first rotational speed and more preferably more than 50% of the first rotational speed. The conveyor (1) according to any of the preceding embodiments, wherein a pitch of the screw of the screw conveyor (1) and an inverted pitch of the passiverotator (10) are substantially equal, preferably the pitch of the screw of the screw conveyor (1) and the inverted pitch of the passive-rotator (10) do differ less than 90%, preferably below 70%, most preferably below 50%. The conveyor (1) according to any of the preceding embodiments, wherein the screw of the screw conveyor (1) comprises a self-lubricating material. The conveyor (1) according to any of the preceding embodiments, wherein the screw of the screw conveyor (1) comprises a metallic material, preferably at least one of iron; or steel; or stainless steel; or brass; or ceramic; or aluminum. The conveyor (1) according to any of the preceding embodiments, wherein the screw of the conveyor (1) comprises a plastic material, preferably at least one of

Polyethylen (PE); or Polypropylen (PP); or Polyvinylchlorid (PVC); or Polystyrol (PS); or Polyethylenterephtalat (PET); or Polycarbonat (PC). The conveyor (1) according to any of the preceding embodiments, wherein the passive rotator (10) comprises at least one of carbon; or composite material; or ceramics; or sintered material. The conveyor (1) according to any of the preceding embodiments, wherein the passive-rotator (10) comprises a metallic material, preferably at least one of iron; or steel; or stainless steel; or brass; or aluminum.

530. The conveyor (1) according to any of the preceding embodiments, wherein the screw of the conveyor (1) comprises a plastic material, preferably at least one of

Polyethylen (PE); or Polypropylen (PP); or Polyvinylchlorid (PVC); or Polystyrol (PS); or Polyethylenterephtalat (PET); or Polycarbonat (PC).

531. The conveyor (1) according to any one of the preceding embodiments, further comprising at least one control unit configured to determine the estimated mass transport of a material against an estimated mass transport based on the speed of the passive-rotor (10).

532. The conveyor (1) according to any one of the preceding embodiments, further comprising at least one control unit configured to compare the volume of a material against an estimated volume transport based on the speed of the passive-rotor (10).

Below, control embodiments will be discussed. These embodiments are abbreviated by the letter "C" followed by a number. Whenever reference is herein made to "control embodiments", these embodiments are meant.

CIO A control unit (100) configured to accept the readout of at least a sensor (S), wherein the control unit (100) further is configured to compute at least one calculation.

C20 The control unit (100) according to the preceding embodiment, wherein the at least one control unit (100) is configured to determine any of

- the sense of a rotation of a passive-rotator (10); and/or

- the speed of the rotation of the passive-rotator (10); and/or

- the speed of the rotation of the passive-rotator (10) over time; and/or

- a relation of the speed of a screw of a screw conveyor (1) and the speed of the rotation of the passive-rotator (10); and/or

- detection of an oscillation of the screw of the screw conveyor (1) and/or the passive-rotator (10); and/or - detection of the power consumption of a motor M; and/or

- comparing the estimated mass transport of a material against an estimated mass transport based on the speed of the passive-rotor (10); and/or

- comparing the volume of a material against an estimated volume transport based on the speed of the passive-rotor (10).

C30 The control unit (100) according to any of the preceding embodiments configured to perform at least one of

- initiate an emergency stop of the conveyor (1); or

- signal a warning if a value of a readout comprises an out-of-boundary value.

Below, method embodiments will be discussed. These embodiments are abbreviated by the letter "M" followed by a number. Whenever reference is herein made to "method embodiments", these embodiments are meant.

M10 A method to sense material flow by the step of determining the material flow that propels a passive-rotator.

M20 The method according to embodiment M10, further comprising the step of determining the direction and a first rotational speed of the passive-rotator.

M30 The method according to any of the preceding embodiments, further comprising the step of transferring the direction and the first rotational speed of the passiverotator to a control unit.

M40 The method according to any of the preceding embodiments, further comprising the step of the control unit receiving a second rotational speed of a motor.

M50 The method according to any of the preceding embodiments, further comprising the step of determining a quantity of the material flow.

Brief description of the Figures

Fig. 1 depicts a screw conveyor with a material flow sensor.

Fig. 2 depicts an alternative embodiment that also falls under the scope of protection.

Figure description Fig. 1 depicts a screw conveyor 1 wherein a screw of the screw conveyor 1 is driven by a motor M. Driven by motor M, the screw of the screw conveyor 1 is forced to carry out a rotational motion. By this rotation, material that is applied in a funnel or hopper, also addressable as chute, crater, sinkhole or filler, may be transported from the funnel side to an outlet of the screw conveyor 1. Once the transported material approaches a passive-rotator 10, the material causes the passive-rotator to carry out a triggered rotational motion. The passive-rotator 10 therefore begins to rotate passively dependent from the mass and/or speed of the transported material. The axle 20 of the passiverotator 10 may convey its rotation via an axle 20 to a sensor S. The axis 20 of the passive-rotator 10 and the axle of the screw of the screw conveyor 1 are depicted coaxially. In the same axis 20, the axle 20 of the passive-rotator 10 and the axle that is driven by the motor M are arranged coaxially. The axle 20 of the passive-rotator 10 is arranged to rotate independently from the axle of the screw of the screw conveyor 1.

The passive-rotator 10 that is driven by the transported material rotates in counter sense to the screw pf the screw conveyor 1 because of the inverted pitch. This prevents the passive-rotator 10 from being rotated by the screw of the screw conveyor in the same rotational sense, i.e., should the passive-rotator 10 rotate in the same direction as the screw of the screw conveyor 1 this would prove that no material or not sufficient material is transported by the screw conveyor 1 and cause the sensor S to report this fact to a control unit (not depicted).

Also, if the passive-rotator 10 rotates significantly slower than the material flow would cause to rotate the passive-rotator 10, the sensor S would report its readout to a control unit (not depicted).

The rotational screw 10 that conveys its rotational sense and speed to the sensor S via the axle 20, causes the sensor S to transmit its readout to a control unit (not depicted).

When the material leaves the downstream extent of the passive-rotator (10) the transported material drops out of the screw conveyor to a destination.

Fig. 2 shows a screw conveyor 1 wherein a screw of the screw conveyor 1 is driven by a motor M. Driven by motor M, the screw of the screw conveyor 1 is forced to carry out a rotational motion. By this rotation, material that is applied in a funnel or hopper, also addressable as chute, crater, sinkhole or filler, may be transported from the funnel side to an outlet of the screw conveyor 1. Once the transported material approaches a passive-rotator 10, the material causes the passive-rotator to carry out a triggered rotational motion. The passive-rotator 10 therefore begins to rotate passively dependent from the mass and/or speed of the transported material. The axle 20 of the passiverotator 10 may convey its rotation via an axle 20 to a sensor S. The axle 20 of the passive-rotator 10 is arranged to rotate independently from the axle of the screw of the screw conveyor 1.

If the passive-rotator 10 rotates significantly slower than the material flow would cause to rotate the passive-rotator 10, the sensor S would report its readout to a control unit (not depicted).

The rotational screw 10 that conveys its rotational sense and speed to the sensor S via the axle 20, causes the sensor S to transmit its readout to a control unit (not depicted).

When the material leaves the downstream extent of the passive-rotator (10) the transported material drops out of the screw conveyor to a destination.