Roll weight system for on-machine dynamic verification

Abstract

To provide a system for measuring the actual total weight of a roll immediately after manufacture in a sheet-making installation.SOLUTION: A radio technique for measuring the total weight of a sheet material on a completed reel spool is to generate a real-time weight readout value. A device for determining the total weight of a sheet material on a roll includes a spool having an RFID tag for identifying a self-weight and / or spool identification number, the spool being for winding a material sheet thereon, means for lifting up a roll of the material wound on the spool, the means having a sensor to detect a force generated by the roll of the material when lifted up so as to send a radio signal including information indicative of the force generated by the roll, and means for calculating the total weight of the material sheet wound on the roll. The actual-weight measurement value is to achieve high-speed dynamic correlation to an on-line weight measurement value. The operation parameter of an actuator and sensor can be adjusted after verification.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates generally to quality control techniques for manufacturing sheet materials, and more particularly to a system for measuring the actual total weight of a roll immediately after production in a sheet making facility. The weight data allows for dynamic verification of the accuracy of online basis weight measurements so that adjustments can be made to the operating conditions of the sheet making process. [Background technology]

[0002] Online measurements are used to detect properties of sheet material during production to allow accelerated control of the sheet making process, thus ensuring sheet quality while reducing the amount of out-of-spec sheet material produced.

[0003] In the production of paper on a continuous papermaking machine, a web of paper is formed from an aqueous suspension of fibers (stock) on a traveling mesh papermaking fabric, and the water is drained by gravity and suction through the fabric. The web is then transferred to the press section where more water is removed by pressure and vacuum. The web then enters the dryer section where steam heated dryers and hot air complete the drying process. The papermaking machine is essentially a water removal system. A typical forming section of a papermaking machine includes an endless running papermaking fabric or wire that runs over a series of water removal elements such as table rolls, foils, vacuum foils, and suction boxes. The stock is carried on top of the papermaking fabric and is dewatered as the stock runs over successive dewatering elements to form a sheet of paper. Finally, the wet sheet is transferred to the press section of the papermaking machine where enough water is removed to form a sheet of paper.

[0004] It is well known to continuously measure certain properties of paper materials to monitor the quality of the finished product. These on-line measurements often include basis weight, moisture content, and sheet caliper, i.e. thickness. The measurements can be used to control process variables in order to maintain output quality and minimize the amount of product that must be rejected due to disturbances in the manufacturing process. On-line sheet property measurements are often made by scanning sensors that periodically traverse the sheet material from end to end. It is conventional to measure the basis weight and / or caliper of the sheet material after it leaves the main dryer section or at the take-up reel with a scanning sensor. Although the basis weight of the produced sheet material is an important property, current manufacturing methods only provide on-line measurement estimates. Summary of the Invention

[0005] The present invention is based, in part, on the development of wireless technology that measures the total weight of sheet material wound onto a finished reel spool, which generates real-time weight readings to a control system. The actual weight measurements allow for fast dynamic correlation and validation against online estimated weight measurements. An operator can then adjust the operating parameters of various actuators and sensors in the papermaking process in response to discrepancies in the measurements.

[0006] In one aspect, the present invention provides a method for producing a method for treating a cancer cell comprising: a sheet of material moving in a machine direction (MD); one or more actuators configured to form a sheet of material containing a liquid; means for drying the liquid laden sheet of material to form a dry sheet of material; means for calculating the basis weight of the dry material sheet; means for winding the produced running dry sheet of material to form a roll of material; and a means for weighing a roll of material. Preferred devices for weighing the roll include, for example, load cells, which refers to any type of sensor useful for measuring force, such as force sensors, force transducers, etc.

[0007] In another aspect, the present invention is directed to a method of operating a sheet making system for producing a continuous sheet running in MD, the method comprising: (a) forming a sheet of material containing a liquid; (b) determining a basis weight of the sheet of material; (c) winding the traveling sheet of material onto a roll; (d) calculating the weight of the sheet material in the roll using the basis weight determined in step (b) to obtain an estimated weight; (e) weighing the roll to determine the actual weight of the sheet of material in the roll.

[0008] In a further aspect, the present invention is directed to an apparatus for determining a total weight of sheet material on a roll, the apparatus comprising: a spool configured to wind a sheet of material, the spool having a radio frequency identification (RFID) tag for identifying a weight and / or a spool identification number; a means for lifting a roll of material wound on a spool, the means comprising a sensor configured to sense a force exerted by the roll of material when lifted, the means transmitting a wireless signal including information representative of the force exerted by the roll of material; and means for calculating a total weight of the sheet of material wound on the roll.

[0009] In one embodiment, the apparatus includes a pair of lifting devices, each with a load cell connected to a Wi-Fi or Bluetooth signal transmitter.

[0010] Although the invention is illustrated as being practiced in papermaking, it is understood that the invention is applicable to other continuous sheet making processes, for example in the production of rubber sheets, plastic films, lithium ion battery electrodes, textiles, etc. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a papermaking system. [Diagram 2] It is a scanning sensor. [Diagram 3] FIG. 13 is a side view of a lift mechanism for metering a roll. [Figure 4] FIG. 1 is a schematic diagram of a lithium ion battery electrode manufacturing system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 1 shows a sheet manufacturing system 10 including a papermaking machine 2, a control system 4, and a network 6. The papermaking machine 2 produces a continuous sheet of paper material 12, which may be over 10 meters wide, that is collected by a take-up reel 14. The paper material 12, which has a particular width and is produced from a pulp suspension feedstock that includes an aqueous mixture of wood fibers and other materials, undergoes various unit operations that are monitored and controlled by a quality control system 4. The network 6 facilitates communication between the components of the system 10.

[0013] The papermaking machine 2 includes a headbox 8, which distributes an aqueous pulp suspension evenly across the machine onto a continuous screen or wire 30 moving in the machine direction (MD). The headbox 8 includes slice openings through which the pulp suspension is distributed onto the screen or wire 30, the slice openings being provided with a suitable structure, such as a mesh, to receive the pulp suspension and allow water or other materials to drain or be removed from the pulp suspension. The formation of the paper sheet 12 is governed by a number of linear actuators 3 that extend transversely across the paper sheet 12 being formed. The actuators 3 control the weight of the sheet in the cross direction (CD). Sensors positioned downstream of the actuators measure the properties of the sheet. The feedstock is fed from the headbox through gaps or elongated orifices 5 onto the wire section 30. The orifices or gaps are relatively narrow openings that extend across the width of the machine. Weight profile control of such an arrangement is achieved by locally adjusting the position of the slice lip across the machine with a motorized linear actuator 3 to vary the size of the gap or orifice immediately adjacent to the actuator. As used herein, the "wet end" forming portion of the sheet making system 10 includes the headbox 8 and wire 30 as well as the section in front of the wire 30, and the "dry end" includes the section downstream of the wire 30.

[0014] The sheet 12 then enters a press section 32 that includes multiple press rolls, where the sheet 12 advances through openings (called "nips") between multiple pairs of counter-rotating rolls in the press section 32. In this manner, the rolls in the press section 32 compress the pulp material forming the sheet 12. This may help remove more water from the pulp material and equalize the properties of the sheet 12 on both sides. A tachometer 38 measures the MD line speed.

[0015] As the sheet 12 travels over a series of heated rolls in the dryer section 34, more water in the sheet 12 evaporates. The calender 36 processes and finishes the sheet 12, for example, by smoothing the sheet 12 and imparting a final finish, thickness, gloss, or other properties. Other materials (such as starch or wax) may be added to the sheet 12 to achieve a desired finish. An array of induction heating actuators 24 applies heat to one or more of the rollers along the CD to control the roll diameter, and thereby the size of the nip. Once processed by the calender 36, the sheet 12 is collected onto the reel 14. A Wi-Fi or Bluetooth receiver is located near the reel 14.

[0016] The sheet making system 10 further includes an array of steam actuators 20 that control the amount of hot steam injected along the CD. The hot steam increases the surface temperature of the paper, allowing for easier removal of water from the paper sheet in the cross direction. The paper material 14 is also sprayed with water in the CD to reduce or prevent over-drying of the paper sheet. Similarly, an array of rewet shower actuators 22 controls the amount of water applied along the CD.

[0017] To control the papermaking process, selected properties of the sheet 12 are continuously measured and the papermaking machine 2 is adjusted to ensure sheet quality. Typical physical properties of paper that can be measured include, for example, thickness, basis weight, moisture content, chemical composition such as ash content, surface roughness, gloss, caliper, color, and crepe pattern surface characteristics. Control of the CD can be achieved by measuring the properties of the sheet using one or more scanners 26, 28 capable of scanning the sheet 12 to measure one or more properties of the sheet 12. For example, the scanner 28 can carry sensors for measuring the dry weight, moisture content, ash content, or any other or additional properties of the sheet 12. The scanner 28 includes a suitable structure for measuring or detecting one or more properties of the sheet 12, such as a set or array of sensors. The scanner 28 is particularly suitable for measuring the dry end dry weight and caliper of the paper product at the take-up reel 14. Suitable caliper scanning sensors are described in US Pat. Nos. 6,967,726 to King et al. and 4,678,915 to Dahlquist et al., which are incorporated herein by reference.

[0018] Measurements from scanners 26 and 28 are provided to a control system 4 that adjusts various actuators or operations of papermaking machine 2 that affect the machine direction and cross direction properties of sheet 12. Machine direction properties of sheet 12 generally refer to the average properties of sheet 12 that vary and are controlled in the machine direction. In this embodiment, control system 4 may control the dry weight of the paper sheet by adjusting the supply of pulp to headbox 8. For example, control system 4 may provide information to a feedstock flow controller that controls the flow of feedstock through valves to headbox 8. Control system 4 includes any hardware, software, firmware, or combination thereof for controlling the operation of sheet making machine 2 or other machines. Control system 4 includes a computer having a processor and memory for storing instructions and data used, generated, and collected by the processor.

[0019] FIG. 2 shows one particular implementation of a scanning sensor located at the dry end just prior to the take-up reel of FIG. 1. In particular, the radiation source and detector are housed within a dual mounting head scanner 58 of a scanner system 50 that may be used to measure one or more properties of the paper being produced. The upper scanner head 54 moves repeatedly back and forth in the CD across the width of a moving sheet 60 moving in the MD so that properties of the entire sheet may be measured. The scanner 58 or gauge is supported by two beams 52 and 62 to which the upper and lower scanning heads 54 and 56 are respectively attached. The operating surfaces of the lower and upper scanner heads 56 and 54 define a measurement gap or window that accommodates the sheet 60. The lower scanner head 56 may include a sheet stabilization system, such as an air bearing stabilizer (not shown), to keep the sheet on a consistent plane as it passes through the measurement window. The movement of the dual scanner heads 54, 56 is synchronized with respect to speed and direction so that they are aligned with each other. The scanner also includes an edge detector (not shown) that measures the sheet width.

[0020] Depending on the characteristic being monitored, the scanning sensor may be configured to operate in a transmission mode or a reflection mode. Basis weight scanning sensors are described, for example, in U.S. Pat. No. 10,935,368 to Tixier and U.S. Patent Application Publication No. 2015 / 0022220 to Tixier and Hughes, which are incorporated herein by reference. For example, the scanner head 54 may house a radiation source that directs a beam of radiation into the moving web or sheet 26, and the scanner head 56 houses a radiation receiver that detects the radiation that has been transmitted through the material. As the dual scanner heads advance back and forth along the CD, the sensor measures one or more characteristics of the web or sheet 60. In a reflection mode, the upper scanner head 54 may house both a radiation source and a detector to measure one or more characteristics of the web or sheet 26.

[0021] During the manufacture of paper, the basis weight, caliper, sheet width, and machine direction speed of the moving paper sheet are continuously monitored. The accumulated data allows one to estimate the weight of the paper that will be wound onto the spool of the finished roll.

[0022] FIG. 3 shows a wound sheet or web roll 82 that has reached a desired diameter and is in contact with a support drum 94. A reel spool 84 includes a shaft 86 that rests on a support rail 92 secured by posts 88, 90. It is understood that each of the two ends of the spool is supported by a support rail. The reel spool 84 may also have a bearing housing (not shown) at each end that is in contact with the support rail. An RFID tag 80 secured to the spool 84 has an assigned identification spool number and / or a spool tare weight. The identification numbers of the multiple spools used in the paper plant and the tare weights associated with the multiple spools may be stored in a database in the control system 4 (FIG. 1). In this manner, once the identification number of a spool is known, its tare weight may be retrieved from the database.

[0023] RFID tags can be either passive, active, or battery-assisted passive. Active tags have a battery and transmit signals intermittently. Battery-assisted passive tags are activated when activated by an RFID reader. Passive tags do not have a battery and use radio energy transmitted by the reader as their energy source. Passive tags include an integrated circuit coupled to a transponder antenna for receiving an interrogation signal from the RFID reader antenna and transmitting a transponder signal. In this example, the tag used is passive. Reading or scanning the spool tag 80 reveals the spool's unique identification number, which allows the tare weight of the spool to be retrieved from a database. Alternatively, the tare weight can be stored in the tag 80 such that reading the tag reveals the tare weight.

[0024] The lifting device 96 includes a cable 98 having a distal end 100 attachable to an overhead or bridge crane (not shown) and a proximal end secured to the upper end of a strain gauge load cell 104 with a crane hook 106 connected to its lower end. The load cell is operably connected to a wireless transmitter 108.

[0025] The load cell 104 can sense the weight of the roll 82, and the transmitter transmits a wireless signal containing information representative of the weight. In operation, a pair of lifting devices, each having a weight sensor and an associated wireless transmitter, is used to lift the roll 82. The two load cells of the pair of lifting devices are calibrated so that their combined reading indicates the weight of the roll. The transmitter device can be configured to operate under any known wireless communication protocol, such as, for example, Wi-Fi and Bluetooth. The weight signal from the pair of transmitter devices is received by a wireless receiver 40 (FIG. 1).

[0026] The RFID reader 110 of FIG. 3 has an antenna capable of transmitting an interrogation signal and receiving an RFID transponder signal from the spool tag 80 in response to the interrogation signal. The spool tag transponder signal includes its identification number and / or tare weight. The RFID reader 110 is operatively connected to a control system 4 (FIG. 1) that processes the transponder signal from the spool RFID tag. The control system 4 also receives a weight signal from a pair of wireless transmitter devices. Based on this information, a computer in the control system calculates the actual total weight of the sheet by subtracting the tare weight of the reel spool 84 from the weight of the roll 82. The computer also compares the actual total weight to an estimated total weight derived from online measurements.

[0027] The present invention can be applied to other sheet fabrication processes that produce liquid-laden materials that are wound into rolls, such as in the manufacture of lithium-ion electrodes. FIG. 4 shows a process for coating metal webs or sheets used in fabricating electrodes for lithium-ion electrochemical cells and batteries. To make an anode, the electrode coating includes an anode active material, such as graphite, and to make a cathode, the electrode coating includes a cathode active material, such as lithium metal oxide. The electrodes include a current collector metal foil that is coated on both sides of the foil with an electrode slurry that may also include carbon black, a binder, and a solvent. After the electrode slurry is applied onto the foil sides, the wet-coated foil is heated in a dryer to extract the solvent, leaving a solid layer of electrode material that adheres to the metal foil. Copper foil is the preferred anode current collector material, and aluminum foil is the preferred cathode current collector material. As shown in FIG. 4, a roll 200 is unwound by an unwinder to provide a continuous metal web or sheet 230 that is coated on the top side with a layer of electrode slurry by a coater 206. The basis weight, thickness, and other characteristics of the metal web or sheet 230 from roll 200 are typically known. Scanning beta gauges 204 and 208 are used to measure the basis weight and / or thickness before and after the electrode slurry is applied by coater 206, respectively.

[0028] The coater 206, such as a tape casting coater, includes an actuator that controls a slot die / doctor blade to regulate the amount of slurry extruded onto the sheet 230. The dryer 210 removes excess solvent and hardens the slurry on the moving coated sheet 232 to form an electrode layer on the sheet. Imaging devices 258 and 278 capture surface images of the coated sheet 232 before and after the dryer 210.

[0029] The scanning beta gauge 212 measures the basis weight and / or thickness of the moving coated sheet 232 exiting the dryer 210 after the calender 254. The rolling supports 234, 236 then reverse the orientation of the moving sheet 238 so that the uncoated side is up, and then the coater 214 applies a layer of electrode slurry to the upper uncoated surface of the moving sheet 238. The basis weight and / or thickness of the double sided coated sheet 240 is measured with the scanning beta gauge 16 before entering the dryer 218. The imaging devices 270, 272, 274 and 276 are strategically positioned to capture top and bottom images.

[0030] Further downstream, a beta gauge housed with an infrared temperature sensor in the scanning device 224 measures the basis weight and / or thickness and temperature of the double-sided coated sheet 242 as the scanning device 224 moves back and forth across the double-sided coated sheet 242. In particular, the basis weight of each electrode layer is measured. A rewinder winds the double-sided coated sheet 242 onto a roll 244 that includes a reel spool 246 supported on rails (not shown). Surface defects on the top and bottom coatings are monitored by imaging devices 226, 228. The roll 244 is typically transported to a calendering station where the double-sided coated electrode layers from the roll are unwound and passed through a calender to be finished and smoothed.

[0031] The reel spool 246 includes an RFID tag capable of transmitting an identification number and / or the tare weight of the reel spool. A pair of lifting devices, shown in Figure 3, is used to obtain the weight of the roll 244 prior to undergoing the calendering process. The total weight of the roll 244 is determined by subtracting the tare weight of the reel spool 246 from the roll weight.

[0032] The foregoing has described the principles, preferred embodiments, and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Accordingly, the above-described embodiments are to be considered as illustrative rather than restrictive, and it is to be understood that changes may be made therein by those skilled in the art without departing from the scope of the invention as defined by the following claims.

Claims

1. A sheet manufacturing system, comprising: a sheet of material moving in a machine direction; one or more actuators configured to form a sheet of material containing a liquid; means for drying the liquid laden sheet of material to form a dry sheet of material; means for calculating the basis weight of said dry sheet of material; means for winding the produced running dry sheet of material to form a roll of material; and means for metering said roll of material.

2. 2. The system of claim 1, wherein the means for winding the traveling sheet of dry material comprises a spool about which the traveling sheet of dry material is wound, the spool having a radio frequency identification tag for identifying the spool and / or a weight of the spool.

3. 1. A method of operating a sheet making system for producing a continuous sheet traveling in the machine direction, comprising: (a) forming a sheet of material containing a liquid; (b) determining a basis weight of the sheet of material; (c) winding the traveling sheet of material onto a roll; (d) calculating the weight of the sheet material in the roll using the basis weight determined in step (b) to obtain an estimated weight; (e) weighing the roll to determine an actual weight of the sheet of material in the roll.

4. 1. An apparatus for determining a total weight of sheet material on a roll, comprising: a spool configured to wind a sheet of material, the spool having a radio frequency identification (RFID) tag for identifying its weight and / or a spool identification number; a means for lifting the roll of material wound on the spool, the means comprising a sensor configured to sense a force exerted by the roll of material when lifted, the means transmitting a wireless signal including information representative of the force exerted by the roll of material; and means for calculating a total weight of the sheet of material wound on the roll.

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