Patent Description:
The loads that the auger and its mechanical drive system experience are dependent upon numerous factors, including but not limited to the height and size of the storage vessel, the depth of the stored material, the characteristics of the stored material, the temperature and humidity of the storage environment, the design of the auger system, the speed of auger rotation and the rate of auger advancement into the stored material. The loads placed on an auger and its drive system lead to stress within them.

As the auger advances into the pile, the auger can bow or deflect as a result of forces that act laterally on the auger. Furthermore, some materials cause the auger to want to climb onto the pile, providing another source for deflection of the auger. The forces from rotating a deflected auger can cause metal fatigue and bearing wear, both of which can result in failure of the auger system. Applying a lateral force to advance an auger into a pile causes cyclical forces as the auger rotates about its axis. Cyclical forces can exacerbate metal fatigue that eventually results in fractures or breakage of the auger tube. Bearing wear can eventually result in excessive bearing temperature leading to bearing failure and subsequent auger failure.

Either bearing failure or auger failure can also occur as a result of excessive torque or thrust loads in response to the auger advancing into the material pile and conveying material from that pile. Auger vibration is another factor which can lead to premature auger failure.

To operate an auger system in an optimally efficient manner, the auger rotational speed and the auger advancement rate into the material pile should be controlled to keep auger parameters such as deflection, torque, thrust, vibration and temperature limited to within an acceptable range. Each of these parameters can cause stress on the auger that may cause it to fail prematurely.

Traditionally, estimating auger parameters to keep them within acceptable levels has been limited to indirect measurements. Loads placed on an auger can be estimated indirectly by monitoring the current drawn through the electrically-powered auger-drive systems or through monitoring the hydraulic pressure on hydraulically-powered auger-drive systems. The auger rotation and advancement can be controlled through feedback from these indirect auger load measurements. Document <CIT> discloses a screw conveyor having a non-contact metal sensor provided on the outside of the device to provide an indirect measurement. Document <CIT> discloses an auger system comprising sensors detecting whether the auger is skewed from a radial line wherein an alignment control system accordingly activates one of the motors of the tractors to realign the auger. Document <CIT> discloses an auger system comprising a sensor monitoring the motor's amperage or load, wherein depending on the detected load, a controller sends a signal to increase/decrease the speed of the motor which adjust the rate of forward movement of the sweep auger. However, these traditional methods of control are only marginally effective as they do not directly measure the actual auger deflection or auger stress. Additionally, indirectly measuring the aforementioned parameters can only provide an inaccurate estimate of stress and deflection, and even that is only possible when the construction of the auger is considered.

Prior to the method described here, direct measurement of auger parameters on an operating auger system has not been accomplished. Since the auger is rotating and also at least partially covered with material as it moves into and conveys material from the pile, taking real-time direct measurements of auger conditions has been problematic because of three factors: <NUM>) the measurements would need to be taken from inside the rotating auger, <NUM>) sufficient power would need to be supplied to the measurement apparatus located inside the rotating auger, and <NUM>) the measurement results would need to be transmitted to a controller located outside the rotating auger. Taking measurements from inside the auger is difficult because the auger is typically made of metal which is conductive and therefore limits wireless transmission of data. Furthermore, since the typical auger rotation rate is between <NUM> and <NUM> rpm the use of electrical unions to transmit power and data is inherently problematic, especially since auger systems are commonly located in hazardous or explosive environments and any traditional revolving contact carries the risk of generating sparks.

The present invention solves these problems, making possible real-time direct measurements of auger parameters inside a rotating auger system. Measurable parameters include, but are not limited to, deflection, stress, torque load, thrust load, vibration and temperature. The measurements of these auger parameters are then transmitted to an auger control system which uses the measurements as feedback to alter the movement of the auger in order to maintain the auger parameters within a desired range and/or to notify the operator of auger conditions.

The present invention is an auger system as defined in claims <NUM>,<NUM>,<NUM> and <NUM>.

Document <CIT> and document <CIT> disclose an auger system according to the preamble of the independent claims.

The internal measurement auger system <NUM> of the present invention may be used in several different types of augers that all have common features. A first type of auger system <NUM> is illustrated in <FIG> and has an auger <NUM> has a shaft <NUM> with an outer diameter <NUM> and an inner diameter <NUM>. The inner diameter <NUM> defines a chamber <NUM>. The auger <NUM> rotates about its central axis <NUM>. Auger advance motors <NUM> advance the auger <NUM> by rotating the entire auger <NUM> laterally along a floor <NUM> of the storage structure <NUM> in which the auger <NUM> is located. The advance motors <NUM> rotate the auger <NUM> about a fixed center point within the center of the storage structure <NUM>. <FIG> shows more detail about the auger system <NUM> shown in <FIG>. An auger drive motor <NUM> rotates the auger <NUM> about its central axis through a gearbox <NUM>. The drive motor <NUM> may be an electric or hydraulic motor. As shown in <FIG>, the motor <NUM> is a hydraulic motor. The auger <NUM> has a proximal end <NUM> and a distal end <NUM> that is supported by a wheel <NUM>. The wheel <NUM> supports the auger <NUM> above the floor <NUM> of the storage structure <NUM> but does not support it with respect to lateral loads. Helical flights <NUM> encircle the auger <NUM> and convey material axially along the auger <NUM> as it rotates about its axis <NUM>. At a point within chamber <NUM>, inside the auger <NUM>, there is a measurement system <NUM>. The measurement system <NUM> has an internal power generator <NUM>, an antenna <NUM> and sensors <NUM>, <NUM>, <NUM>. The internal power generator <NUM> is shown more thoroughly in <FIG>. The power generator <NUM> has a sealed tube <NUM> that contains a permanent magnet <NUM> that rides within the sealed tube <NUM>. The tube <NUM> is surrounded by a coil <NUM>. As the auger <NUM> rotates about its central axis <NUM>, the magnet <NUM> falls through the coil <NUM> as gravity acts on it. As the magnet <NUM> falls through the coil <NUM> it generates electricity. In this manner, the power generator <NUM> is completely decoupled from any part of the auger system <NUM> so that there is no mechanical link to any part of the auger system <NUM> outside of the auger <NUM> itself. The power generator <NUM> uses its magnet <NUM> as a weight acted upon by gravity to produce power, and it is contemplated that a weight other than the magnet <NUM> itself may drive the power generator <NUM> to produce the necessary power for the measurement system <NUM> to function. The electricity from the power generator <NUM> may be passed through power conditioning equipment <NUM> such as voltage regulators and/or rechargeable batteries to provide stable and predictable power to the sensors <NUM>, <NUM>, <NUM> and to provide power to a wireless data transmitter <NUM>. The sensors are an accelerometer <NUM>, a thermocouple <NUM> and a strain gauge <NUM>. These sensors <NUM>, <NUM>, <NUM> may be placed in appropriate locations along the length of the auger <NUM>. Additionally, it may be desirable to place more than one of the sensors <NUM>, <NUM>, <NUM> along the length of the auger <NUM> to take data at various points along the auger <NUM>. Each of the sensors <NUM>, <NUM>, <NUM> generates a signal that corresponds to values it measures within the chamber <NUM> of the auger <NUM>. It is contemplated that a replaceable battery may be used in place of the power generator <NUM>, however this is less desirable than using a power generator <NUM> because a battery would need periodic replacement and may contain chemicals that could potentially leach out into the auger or the stored material. Having the measurement system <NUM> completely contained within the chamber <NUM> inside the auger <NUM> protects it from damage and allows it to function for an extended period of time without maintenance.

An alternate method of internal power generation which uses a focused light source, such as a laser, together with a photovoltaic detector is shown <FIG>. In this method, power generator <NUM> is replaced with a focused light beam <NUM> which illuminates photovoltaic detector <NUM>. The current generated by detector <NUM> is processed in the power management circuit and used to power the sensors <NUM>, <NUM> & <NUM>.

In some instances, it may be desirable to measure overall deflection along a predetermined length of the auger <NUM>. A method of directly measuring the deflection along auger <NUM> is shown in <FIG> and <FIG>. A laser and detector unit <NUM> that can produce a laser beam <NUM> and detect the reflected laser beam <NUM> is located near the gear box <NUM>. The laser and detector unit <NUM> shines the laser beam <NUM> on a concentrically tiered reflector <NUM>. The concentrically tiered reflector <NUM> includes a first reflective surface <NUM> that is aligned with the central axis <NUM> of the auger <NUM>. A second reflective surface <NUM> is located farther from the laser and detector unit <NUM> than the first reflective surface <NUM>. A third reflective surface <NUM> is located farther from the laser and detector unit <NUM> than the second reflective surface. When the auger <NUM> is in its undeflected state, that corresponds to having no net load placed up on it, the laser beam will strike the first reflective surface <NUM> and the detector unit <NUM> will be able to determine the measured distance corresponding to the laser beam <NUM> striking the first reflective surface <NUM> as shown in <FIG>. As the auger <NUM> deflects, it is bent so that the laser beam <NUM> strikes the second reflective surface <NUM> (as shown in <FIG>) and the detector unit <NUM> determines that the auger <NUM> has bent enough for the laser beam <NUM> to strike the second reflective surface <NUM> by calculating the corresponding distance. As the auger <NUM> is bent still further, the detector unit <NUM> determines the laser beam has struck the third reflective surface <NUM> as shown in <FIG>. Upon determining the corresponding deflection, the laser and detector unit <NUM> is able to send a signal corresponding to the deflection. Each successive reflective surface <NUM>, <NUM>, <NUM> extends radially outward of the nearer reflective surface so that deflection may be calculated based on which reflective surface <NUM>, <NUM>, <NUM> the laser beam strikes. <FIG> shows a method for measuring auger deflection with photovoltaic detectors. In this case, a focused light beam <NUM>, which may be a laser beam, strikes a photovoltaic detector array <NUM>, typically consisting of concentric photovoltaic detectors <NUM>, <NUM>, <NUM> that send a signal according to the location where the light beam <NUM> strikes each individual photovoltaic detector <NUM>, <NUM>, <NUM> within the photovoltaic detector array <NUM>. Larger deflection in the auger <NUM> will correspond to the light beam <NUM> striking the photovoltaic detector array <NUM> more radially outward.

Within the internal measurement system <NUM> that includes the power generator <NUM> wireless data transmitter <NUM> and sensors <NUM>, <NUM>, <NUM>, there are no contacts that can cause sparks because there is no frictional contact having relative movement with respect to another contact as would occur in rotating unions or brushes. The wireless data transmitter <NUM> can send data down the length of the auger <NUM> by emitting a radio frequency, but may have difficulty sending data through straight through the metal sidewall <NUM> of the auger <NUM>. It is not necessary that the signal from the wireless data transmitter <NUM> be sent through the sidewall <NUM> because that data sent down the length of the auger <NUM> is detected by a receiver antenna <NUM> that may be placed in a location that does not rotate such as the fixed end plate <NUM> that shown in <FIG>. This separation of the receiver antenna <NUM> and the wireless data transmitter <NUM> provides a physically decoupled connection that is not susceptible to damage from the stored material and will not generate sparks. The transmitter <NUM> and receiver antenna <NUM> do not make contact. The end plate <NUM> acts a receiver base that is fixed from rotation with respect to the auger <NUM>. It is contemplated that other locations than the end plate <NUM> may act as a receiver base as long as that location for the receiver antenna <NUM> allows the receiver antenna <NUM> to receive signals within the auger. The location of the receiver antenna <NUM> need only provide a means for receiving the signal from the transmitter <NUM>.

The data signal from the receiving antenna <NUM> must be transmitted out of the auger <NUM> and into a feedback control system <NUM>. This may be done by using a wireless repeater <NUM> that acts as a second transmitter directed to a receiver <NUM> as shown in <FIG> or a rotating electrical union <NUM> that is located outside of the storage structure <NUM> and away from any potentially explosive dust from the stored material as shown in <FIG>. This allows the auger <NUM> and gearbox <NUM> to rotate with respect to the electrical union <NUM> as the advance motors <NUM> that rotate the auger <NUM> laterally about its fixed center within the storage structure <NUM>. The rotation rate of this electrical union is extremely slow, since it rotates at the same rate in which the auger cycles around the floor of the storage structure. Typically, this rotation rate is on the order of <NUM> cycle every <NUM> hours or more, so there is minimal risk of spark.

The feedback control system <NUM> receives signals from the sensors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> as described above. The control system <NUM> may use information from the signals to change inputs to the components that move the auger <NUM> such as the auger advance motor(s) <NUM>, and auger drive motor <NUM> so that the auger <NUM> is not subjected to loading that would cause damage to it or the storage structure <NUM>. The feedback control system <NUM> contains predetermined values that correspond to operating parameters that are acceptable for the auger <NUM> to operate under. For instance, the feedback control system <NUM> will have predetermined values for acceptable ranges of temperature, acceleration of the auger <NUM>, strain within the auger <NUM>, and/or deflection of the auger <NUM>. The feedback control system <NUM> receives signals from the respective sensors <NUM>, <NUM>, <NUM>, <NUM> and compares the value that each signal represents to one of the predetermined values it contains with respect to particular operating parameters. If the feedback control system <NUM> compares the value corresponding to a particular signal and that signal corresponds to a value condition outside of an acceptable range of operating conditions, the feedback control system <NUM> will alter inputs to the auger system <NUM> until the auger <NUM> is operated in a manner that puts the particular value or values measured by the sensors <NUM>, <NUM>, <NUM>, <NUM> within the predetermined values or ranges of values so the auger <NUM> is not damaged. The inputs to the auger system <NUM> that the feedback control system <NUM> can alter include the inputs to the components that drive the auger <NUM> such as the auger advance motor <NUM> and the drive motor <NUM>. Depending on the types of motors <NUM>, <NUM> used, the feedback control system <NUM> may alter electrical or hydraulic power to these motors <NUM>, <NUM> to achieve the desired conditions within the auger <NUM>.

<FIG> and <FIG> illustrate a linear auger <NUM> that has a proximal end <NUM> that is near auger drive motor <NUM> connected to a gearbox <NUM> that rotates auger <NUM>. The auger advance motor (not shown, located inside carriage <NUM>) drives an auger advance shaft <NUM>. The auger advance shaft <NUM> drives the carriage <NUM> and advances the auger <NUM> laterally through the pile within the storage structure <NUM>. In this case, the proximal end <NUM> is on the left hand side as shown in <FIG>. As such, a distal portion <NUM> of the auger <NUM> is located at some distance away from the proximal end <NUM> and may be deflected as the auger <NUM> is advanced through stored material because the distal portion <NUM> is not supported to the extent that the proximal end <NUM> is supported. As shown in <FIG>, the internal measurement system <NUM> is located at some point inside of the auger <NUM>. In the same manner as described above, the data taken from the auger <NUM> is processed by a feedback control system <NUM> that ensures that the auger <NUM> is advanced and rotated at appropriate rates to prevent damage to the auger <NUM>. In this case a receiving antenna (not shown) is attached to an endplate fixed to carriage <NUM> and mounted so as to protrude inside auger <NUM>. The receiving antenna receives a radio signal from the measurement system <NUM> located within the auger <NUM> in the same manner as show in <FIG>.

<FIG> and <FIG> illustrate a drum <NUM> that conveys cut material <NUM> into a mining machine <NUM>. The drum <NUM> rotates between a transmission <NUM> and a bearing plate <NUM>. Carbide teeth <NUM> extend from the drum <NUM> to cut into the material in the path of the drum <NUM> and convey the material into the mining machine <NUM>. The drum contains the internal measurement system <NUM> as described above and transmits data taken to an antenna <NUM> fixed with respect to the bearing end plate <NUM>. In the mining machine <NUM> the auger advance motor (not shown) is contained within the body of the mining machine <NUM> and advances the drum <NUM> through movement of crawler tracks <NUM>. A drive motor <NUM> is connected with a belt <NUM> to the drum <NUM> and through the transmission <NUM> rotates the drum <NUM> about its axis in the same manner as auger <NUM> is rotated. As discussed above, the measurements can be used to change the operation of the drum <NUM> or any other component of the mining machine <NUM>.

<FIG> and <FIG> illustrate another version of a mining machine <NUM> that has a drum <NUM> that is supported in its center about a pivotable arm <NUM>. The proximal ends <NUM> of the drum <NUM> are supported by the arm <NUM> and distal ends <NUM> are cantilevered outwardly from the arm <NUM>. <FIG> shows the internal measurement system <NUM> within the drum <NUM>. In this case, the drum <NUM> includes openings <NUM> that allow the signal from the internal measurement system to be transmitted through the drum <NUM> and received by a receiving antenna <NUM> that is fixed from rotation with respect to the drum <NUM>.

In some instances it may be desirable for an auger <NUM> to have slip rings <NUM> to transmit power and/or signal information through the auger <NUM>. <FIG> shows an auger <NUM> with slip rings <NUM> near the gearbox <NUM> of the auger <NUM>. The slip rings <NUM> may be used for sending power to sensors <NUM> in the auger <NUM> and may also be used to transmit signal data from sensors <NUM> within the auger <NUM>. The slip rings <NUM> are located within a dust tight enclosure <NUM>. The slip rings <NUM> can be used with any of the aforementioned configurations. When slip rings <NUM> are used to transmit signal data from sensors to a location outside of the auger <NUM>, a transmitter <NUM> is not necessary for this purpose.

Claim 1:
An auger system (<NUM>) comprising: an auger (<NUM>) rotatable about a central axis (<NUM>), said auger (<NUM>) having a shaft (<NUM>) including an outer diameter (<NUM>) and an inner diameter (<NUM>), said auger (<NUM>) having an inner chamber defined by said inner diameter (<NUM>), said outer diameter (<NUM>) including features for conveying material adjacent to said auger (<NUM>) ; characterized in that the auger system further comprises a power source located within said inner chamber, said power source providing power to a measurement system (<NUM>) contained within said inner chamber, said measurement system (<NUM>) including a sensor (<NUM>, <NUM>, <NUM>) for measuring a condition within said auger (<NUM>) and said sensor (<NUM>, <NUM>, <NUM>) producing a signal, said signal being transmitted via a transmitter (<NUM>) located inside said inner chamber to a receiver (<NUM>) spaced from said transmitter (<NUM>), said receiver (<NUM>) transmitting said signal to a control system (<NUM>), said control system (<NUM>) comparing said signal to a predetermined value to determine whether said condition is within an acceptable range; said control system (<NUM>) altering inputs into components for moving said auger (<NUM>) until said condition is within an acceptable range.