System and method for manufacturing mat-coated cementitious board with in-line bond measurement using non-contact ultrasonic transducers

Abstract

[0003] Embodiments of the system and method for evaluation of mat-coated cementitious board samples can be used to determine bond strength values ​​of the samples. The translation assembly is configured to translate a pair of non-contact ultrasonic transducers in an XY plane relative to a sample supported in a support fixture such that the sample is interposed between the transducers. The controller is configured to use ultrasonic signals from the transducers to determine the bond strength of at least one facing of the mat-coated cementitious board sample. For example, during continuous production of mat-coated cementitious board, a transducer array can be installed downstream of a kiln to provide a system and method for continuously measuring the bond strength of mat-coated cementitious board.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 484,736, filed February 13, 2023, entitled "System and Method for Manufacturing Mat-Faced Cementitious Board with In-Line Bond Measurement Using Non-Contact Ultrasound Transducers," which claims the benefit of priority to U.S. Provisional Patent Application No. 18 / 419,213, filed January 22, 2024, entitled "System and Method for Evaluating Mat-Faced Cementitious Board with Non-Contact Ultrasound Transducers," both of which are incorporated herein by reference in their entireties. [Background technology]

[0002] The present disclosure relates to evaluating mat-coated cementitious boards, and more particularly to systems and methods for evaluation of bond characteristics of mat-coated cementitious board samples.

[0003] Gypsum wallboards having a gypsum-based core reinforced on their outer major surfaces with facings or scrims (collectively referred to herein as mat-coated) are well known in the art. The facings are typically paper for dry environments, such as interior drywall products. However, in some applications, glass or polymer-based mats are used for products that may be exposed to high humidity conditions. For example, such boards are useful in exterior cladding products. Glass mat gypsum board cladding can be applied to studs, joists, or rafters of residential or commercial buildings to strengthen the structure and provide fire resistance and some degree of water resistance. The cladding provides a base for applied exterior cladding (e.g., brick, siding, stone, etc.), with additional moisture and vapor barrier substrates optionally applied between them.

[0004] Glass mat gypsum board can also be utilized in interior applications where the board may be exposed to significant moisture. For example, glass mat-coated boards can be used in various interior locations, such as sink or bathtub surrounds, backsplashes, etc. The glass mat-coated board provides a base for ceramic tiles, etc., that are applied, for example, using mortar or mastic to secure the tile to the base. The glass mat provides some water and mildew resistance over time when water seeps through the hardened mortar or mastic, for example, through cracks in the tile or grout.

[0005] The manufacturing process for mat-coated gypsum board typically involves depositing a cementitious slurry (e.g., a mixture containing stucco and water, where stucco refers to calcined gypsum and is typically composed primarily of calcium sulfate hemihydrate and / or anhydrous calcium sulfate) onto a first mat coating and covering the wet slurry with a second mat coating, usually of the same type, such that the cementitious slurry is sandwiched between the two mat coatings. The cementitious slurry is allowed to harden (e.g., to form an interlocking matrix of calcium sulfate dihydrate, called set gypsum) and subjected to drying in a kiln to remove excess water not consumed in the hydration process and produce a solid article.

[0006] Therefore, the manufacturing process for mat-coated gypsum board often requires that the covering material be sufficiently permeable so that excess water can be removed from the cementitious slurry during the drying process. For example, nonwoven glass fiber mats are often used as covering materials, where the spaces between the fibers provide permeability. If untreated, the permeability of the fiber mat covering material can reduce the water resistance of the cementitious article by allowing water to penetrate the mat and contact the cementitious core during use. To alleviate this problem, exterior coatings of water-resistant materials can be applied.

[0007] The strength of the bond between the mat and the cementitious core is commonly used to evaluate the quality of mat-coated cementitious boards. Bond strength is traditionally measured by performing a destructive test, in which the mat is pulled away from the core in the vertical Z-direction (perpendicular to the plane of the mat) and the amount of force required to separate the mat is measured. This measurement technique is reliable and effective, but it is destructive to the sample.

[0008] There is a continuing need in the art to provide additional solutions to improve the production of cementitious boards, for example, there is a continuing need for techniques for evaluation of bond strength of mat-coated cementitious boards.

[0009] It will be understood that this background discussion is prepared to assist the reader and should not be construed as indicating that any of the problems presented have been recognized in the art per se. While the principles described may, in some aspects and embodiments, alleviate problems inherent in other systems, it will be understood that the scope of the innovation that is protected is defined by the appended claims, and not by the ability of any disclosed feature to solve any particular problem described herein. Summary of the Invention

[0010] In one aspect, the present disclosure is directed to an embodiment of a system for evaluation of mat-coated cementitious board samples, in an embodiment, the evaluation system includes at least one non-contact (air-coupled) ultrasonic transmitter transducer and at least one non-contact ultrasonic receiver transducer.

[0011] In another aspect, the present disclosure describes an embodiment of a method for evaluating mat-coated cementitious board samples. In an embodiment, the evaluation method includes evaluating the bond strength of the mat-coated cementitious board samples using a system for evaluating mat-coated cementitious board samples constructed according to the principles of the present disclosure. In an embodiment, the evaluation method includes measuring the bond strength of the mat-coated cementitious board samples using a non-contact ultrasonic transmitter transducer and a non-contact ultrasonic receiver transducer.

[0012] In yet another aspect, the present disclosure describes an embodiment of a system for manufacturing a mat-coated cementitious board. In the embodiment, the manufacturing system includes a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array disposed adjacent to a downstream end of a conveyor section extending along the machine direction. The transducer arrays extend along a transverse axis of the conveyor section perpendicular to the machine direction. The transducer arrays are disposed in a spaced-apart relationship along a vertical axis perpendicular to both the machine direction and the transverse axis, so that the mat-coated cementitious board can pass between the transducer arrays along the machine direction.

[0013] In one embodiment, a system for manufacturing a mat-coated cementitious board includes a kiln, a conveyor, and a board bond measurement system. The mat-coated cementitious board has a mat bonded to a cementitious core, the cementitious core being formed from an aqueous cementitious slurry.

[0014] The kiln is configured to remove excess water from the aqueous cementitious slurry. The conveyor is configured to transport the cementitious board away from the kiln along a machine direction. The conveyor includes an upstream support surface and a downstream support surface, both of which extend along the machine direction and a transverse axis perpendicular to the machine direction. The upstream and downstream support surfaces are in a discontinuous relationship with each other to define an unsupported span therebetween.

[0015] The board bond measurement system includes a non-contact ultrasonic transmitter transducer array, a non-contact ultrasonic receiver transducer array, a non-transitory computer-readable medium, and a controller. The non-contact ultrasonic transmitter transducer array and the non-contact ultrasonic receiver transducer array are disposed in an unsupported span such that the transducer arrays extend along a transverse axis. The transducer arrays are disposed in a spaced-apart relationship along a vertical axis perpendicular to both the machine direction and the transverse axis, such that a mat-coated cementitious board is adapted to move along the machine direction from an upstream support surface to a downstream support surface and pass between the transducer arrays along the vertical axis. The ultrasonic receiver transducer array is configured to transmit an ultrasonic receive signal from the ultrasonic receiver transducer array. The ultrasonic receive signal indicates the intensity of an ultrasonic signal received by the ultrasonic receiver transducer array from the ultrasonic transmitter transducer array.

[0016] The non-transitory computer-readable medium carries a board bond measurement program. The controller is in operative arrangement with the ultrasonic receiver transducer array to receive ultrasonic receive signals from the ultrasonic receive transducer array. The controller is in operative arrangement with the non-transitory computer-readable medium such that the controller is configured to execute the board bond measurement program contained in the non-transitory computer-readable medium. The board bond measurement program includes a bond strength module configured to determine a numerical bond strength value of the mat-coated cementitious board based on the ultrasonic receive signals.

[0017] In yet another aspect of the present disclosure, an embodiment of a method for manufacturing a mat-coated cementitious board is described. In the embodiment, the method includes passing the mat-coated cementitious board along a machine direction between a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver array disposed adjacent a downstream end of a conveyor section extending along the machine direction. The transducer array extends along a cross axis of the conveyor section perpendicular to the machine direction. The transducer arrays are disposed in a spaced apart relationship along a vertical axis perpendicular to both the machine direction and the cross axis.

[0018] In one embodiment, a method of making a mat-coated cementitious board includes applying a mat to a cementitious core formed from an aqueous cementitious slurry. The mat-coated cementitious board is dried in a kiln to remove excess water from the aqueous cementitious slurry. The mat-coated cementitious board is conveyed along a machine direction away from the kiln. The mat-coated cementitious board extends along the machine direction and along a transverse axis perpendicular to the machine direction.

[0019] The mat-coated cementitious board passes along the machine direction past a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array. The transducer arrays extend along a transverse axis and are spaced apart from one another along a vertical axis perpendicular to the machine direction and the transverse axis, such that the mat-coated cementitious board passes between the transducer arrays along the vertical axis. Ultrasonic signals are emitted from the ultrasonic transmitter transducer array such that the ultrasonic signals pass through the mat-coated cementitious board and are received by the ultrasonic receiver transducer array. The ultrasonic receiver transducer array transmits ultrasonic receive signals to a controller. The ultrasonic receive signals indicate the intensity of the ultrasonic signals received by the ultrasonic receiver transducer array from the ultrasonic transmitter transducer array. A board bond measurement program stored in a non-transitory computer-readable medium is executed using the controller to generate a numerical bond strength value for the mat-coated cementitious board based on the ultrasonic receive signals.

[0020] Further and alternative aspects and features of the disclosed principles will be understood from the following detailed description and the accompanying drawings. As will be understood, the systems and techniques for evaluating mat-coated cementitious board samples and for manufacturing mat-coated cementitious boards disclosed herein can be implemented and used in other different embodiments and can be modified in various ways. Accordingly, it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the scope of the appended claims. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective elevation view of one embodiment of a system for evaluation of mat-coated cementitious board samples constructed in accordance with the principles of the present disclosure, illustrating a mat-coated cementitious board sample mounted in the system; [Figure 2]FIG. 2 is another perspective elevation view of the evaluation system of FIG. 1 , including an enlarged detailed view of the non-contact ultrasonic transmitter transducer and the non-contact ultrasonic receiver transducer of the evaluation system, with the mat-coated cementitious board sample disposed therebetween along an axis perpendicular to a plane defined by the board sample. [Figure 3] FIG. 1 is a schematic diagram of a non-contact ultrasonic transmitter transducer and a non-contact ultrasonic receiver transducer of one embodiment of a system for evaluation of a mat-coated cementitious board sample constructed in accordance with the principles of the present disclosure, with the mat-coated cementitious board sample disposed therebetween along an axis perpendicular to a plane defined by the board sample. [Figure 4] FIG. 1 is a fragmentary schematic diagram of one embodiment of a system for manufacturing mat-coated cementitious board constructed in accordance with the principles of the present disclosure, illustrating a mat-coated cementitious board being transported in the machine direction past a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array such that the board passes between the transducer arrays along an axis perpendicular to a plane defined by the board. [Figure 5] FIG. 1 is a schematic top view of an exemplary transducer array suitable for use in a system for manufacturing mat-coated cementitious boards constructed in accordance with the principles of the present disclosure.

[0022] It should be understood that the drawings are not necessarily to scale, and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details that are not necessary for an understanding of the disclosure or that make other details difficult to perceive may have been omitted. Of course, it should be understood that the disclosure is not limited to the specific embodiments illustrated herein. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present disclosure provides various embodiments of systems and methods for evaluating mat-coated cementitious board samples to measure the bond strength of the mat-coated cementitious board samples. Embodiments of systems and methods for evaluating mat-coated cementitious board samples according to the principles of the present disclosure include at least one air-coupled ultrasonic transducer that can be used to effectively determine the bond strength of the mat-coated cementitious board using non-destructive, non-contact ultrasonic techniques.

[0024] Embodiments of systems and methods for evaluation of mat-coated gypsum board samples according to the principles of the present disclosure use air-coupled ultrasonic pulse velocity techniques to find the attenuated signal intensity through the sample and correlate it to the bond strength between the mat facing (e.g., glass mat facing) and cementitious core (e.g., gypsum core) of the sample. In embodiments, the attenuated signal intensity data is correlated to bond strength. This quantitative measurement technique provides a non-destructive approach for evaluation of bond strength in mat-coated cementitious boards. In embodiments, ultrasonic evaluation of air-coated bonds using embodiments of systems and methods for evaluation of board samples according to the principles of the present disclosure can be used as a non-destructive bond strength quantification method for glass mat gypsum boards.

[0025] Embodiments of a system and method for evaluating mat-coated gypsum board samples to measure bond strength according to principles of the present disclosure include predicting bond strength using air-coupled ultrasonic techniques. In embodiments, the bond strength of mat-coated cementitious board samples can be determined using attenuated signal intensity data and a database of mat-coated cementitious board sample data that includes attenuated signal intensity data and destructive Z-joint tensile data for each such sample. In embodiments, the measured attenuated signal intensity for a given sample can be compared to the database to extrapolate the Z-joint tensile value for the sample without performing such destructive testing.

[0026] In an embodiment, an air-coupled ultrasonic transducer traverses over a predetermined area of ​​a mat-coated cementitious board sample, transmitting an ultrasonic signal from the transmitter transducer through the sample to the receiver transducer. The controller is programmed to determine signal loss (or attenuation) from a parent signal based on the signal received at the receiver transducer. In an embodiment, the controller is programmed to determine areas of the sample that have "good" or sufficiently strong bonds and "bad" or unacceptably weak bonds based on the predetermined value of signal loss, and the sample can be qualified or rejected based on the predetermined criteria for signal loss.

[0027] In another aspect of the present disclosure, the present disclosure describes embodiments of a system for manufacturing mat-coated cementitious boards. The present disclosure provides various embodiments of a system for continuously measuring the bond of mat-coated cementitious boards during continuous production, which may be used in connection with the manufacture of various mat-coated cementitious products, including, for example, glass mat gypsum boards. Embodiments of a system for measuring mat-coated cementitious boards during continuous production according to principles of the present disclosure can be used online in a continuous manufacturing process to effectively determine the degree to which one or both mat-coated facings have bonded to the cementitious core (e.g., as a function of attenuated ultrasonic signal intensity) at a predetermined location, such as downstream of a kiln, without contacting the mat-coated cementitious board as it moves along the board line. In embodiments, the system can be configured to issue an operator alert when a target attenuated ultrasonic signal intensity profile is not met.

[0028] In an embodiment, the manufacturing system includes a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver array disposed adjacent a downstream end of a conveyor section extending along a machine direction. The transducer arrays extend along a cross axis of the conveyor section that is perpendicular to the machine direction. The transducer arrays are disposed in a spaced-apart relationship to one another along a vertical Z-axis that is perpendicular to both the machine direction and the cross axis, so that a mat-coated cementitious board moving in the machine direction passes between the transducer arrays along the vertical axis.

[0029] In another aspect, the present disclosure describes an embodiment of a method for manufacturing a mat-coated cementitious board. In an embodiment, the manufacturing method includes passing the mat-coated cementitious board along a machine direction between a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver array disposed adjacent to a downstream end of a conveyor section extending along the machine direction. The transducer array extends along a cross axis of the conveyor section that is perpendicular to the machine direction. The transducer arrays are disposed in a spaced-apart relationship along a vertical Z-axis that is perpendicular to both the machine direction and the cross axis, such that the mat-coated cementitious board passes between the transducer arrays along the vertical axis.

[0030] Referring now to the figures, one embodiment of a system 20 for evaluation of mat-coated cementitious board samples constructed in accordance with the principles of the present disclosure is shown in Figures 1 and 2. Referring to Figures 1 and 2, the evaluation system 20 is configured to move axially aligned air-coupled ultrasonic transducers 21, 22 over a predetermined field in a plane defined by an X-axis and a vertical Y-axis in which a mat-coated cementitious board sample 25 is disposed. In an embodiment, the ultrasonic transducers 21, 22 include at least one non-contact ultrasonic transmitter transducer 21 and at least one non-contact ultrasonic receiver transducer 22, with the mat-coated cementitious board 25 disposed therebetween along a vertical Z-axis that is perpendicular to both the X-axis and the Y-axis, such that the transmitter transducer 21 can emit an ultrasonic signal along the Z-axis that passes through the board sample 25 and is received by the receiver transducer 22.

[0031] In an embodiment, the evaluation system 20 includes a controller 30 in operative communication with the axially paired transducers 21, 22 and configured to capture ultrasonic measurements using the axially paired transducers 21, 22 as they move over a predetermined field in the XY plane. In an embodiment, the controller 30 is configured to measure the attenuation signal strength, i.e., the difference between the ultrasonic signal emitted by the transmitter transducer 21 and the ultrasonic signal received by the receiver transducer 22, as the axially paired transducers 21, 22 move over the predetermined field in the XY plane. In an embodiment, the controller 30 is configured to determine an average signal strength for the predetermined field in the XY plane. In an embodiment, the controller 30 of the evaluation system 20 is configured to use the ultrasonic measurements over the predetermined field in the XY plane to determine a bond strength value for the mat-coated cementitious board sample 25 correlated to the bond strength between at least one mat 31, 32 and the cementitious core 34 of the mat-coated cementitious board sample 25 (see FIG. 3 ). In an embodiment,

[0032] In an embodiment, system 20 can include air-coupled ultrasonic transducers 21, 22 used to predict the bond strength of glass mat gypsum board 25. The glass mat-gypsum core bond can be identified as relatively strong or weak from the attenuation signal intensity map obtained using this non-contact technique. For example, in an embodiment using transducers in the 100 kHz to 500 kHz range, a value in the range of -28 dB to -30 dB can be used as the boundary between a weak face mat bond and a sufficiently strong bond.

[0033] In embodiments, the evaluation system 20 may be configured for use with mat-coated cementitious board samples 25 of any suitable size and / or shape. For example, in embodiments, the sample 25 may have a rectangular shape, such as a nominal 1-foot by 2-foot rectangle. In embodiments, the mat-coated cementitious board sample 25 may be square, such as a nominal 6-inch by 6-inch square. In embodiments, the mat-coated cementitious board sample 25 has a nominal 4-foot width and a suitable length, for example, a length ranging from 2 feet to 4 feet. In embodiments, the sample 25 may include tapered edges along its length. In embodiments, the sample 25 may have at least one mat facing 31, 32 that is substantially planar.

[0034] In the illustrated embodiment, the evaluation system 20 includes a support fixture 35, a translation assembly 40, a non-contact ultrasonic transmitter transducer 21, a non-contact ultrasonic receiver transducer 22, and a controller 30. The support fixture 35 is configured to support a mat-coated cementitious board sample 25 such that the ultrasonic transducers 21, 22 can be positioned above and below the sample 25 in aligned relationship with one another along the Z-axis for evaluating the sample 25. The ultrasonic transducers 21, 22 can be attached to the translation assembly 40 such that the mat-coated cementitious board sample 25 can be supported by the support fixture 35 and the board 25 is disposed between the ultrasonic transducers 21, 22 along a vertical Z-axis. The translation assembly 40 is configured to translate the axially aligned air-coupled ultrasonic transducers 21, 22 over a predetermined field in a plane defined by an X-axis and a vertical Y-axis where the mat-coated cementitious board sample 25 is supported within the support fixture 35.

[0035] Referring to FIG. 1 , in an embodiment, the support fixture 35 includes supports 41, 43 that allow the sample 25 to be supported while providing an opening below the sample 25, and one of the transducers 22 can be disposed below the sample 25 in the opening such that only air exists between the transducer and the sample (see FIG. 2 ). The illustrated support fixture includes a first platform 41 and a second platform 42 that are spaced apart from each other along the Y-axis and define an opening 43 therebetween. The platforms 41, 42 are configured to support the sample 25 such that a central region of the sample is unsupported and accessible from below the sample 25 through the opening 43. In other embodiments, the support fixture 35 can have a different configuration, as will be understood by those skilled in the art. For example, in an embodiment, the support fixture 35 can include a single table with a support surface having a central opening at least as large as the desired XY analysis field of the sample 25.

[0036] 2, the illustrated translation assembly 40 comprises a three-axis (xyz) positioning stage controlled by the controller 30. In an embodiment, the translation assembly 40 includes a Z-rail 51 extending along the Z-axis and having a first transducer arm 52 and a second transducer arm 53 mounted thereon. The first transducer arm 52 and the second transducer arm 53 extend along the Y-axis and support the transmitter transducer 21 and the receiver transducer 22, respectively, in a first XY plane and a second XY plane such that the transducers 21, 22 are axially aligned along the Z-axis and the sample 25 is disposed therebetween along the Z-axis. A support fixture 35 is provided for supporting the sample 25 along the Z-axis between the first XY plane and the second XY plane.

[0037] In an embodiment, the first transducer arm 52 and the second transducer arm 53 are independently movable along the Z-rail 51 to change the position of each of the transducers 21, 22 along the Z-axis. In an embodiment, the transducer arms 52, 53 are extendable along the Y-axis to selectively move each of the transducers 21, 22 along the Y-axis relative to at least one of the board specimen 25 and the Z-rail 51.

[0038] The translation assembly 40 includes an X-rail 54 with a carriage 55 on which a Z-rail 51 is mounted. The carriage 55 is movable along the X-rail 54 to selectively translate the transducers 21, 22 along the X-axis relative to the board specimen 25.

[0039] The translation assembly 40 includes a pair of Y-rails 57 with a mounting plate 58 connected therebetween and an X-rail 54 attached to the mounting plate 58. The mounting plate 58 is movable along the Y-rails 57 to selectively translate the transducers 21, 22 along the Y-axis relative to the board specimen 25.

[0040] In embodiments, translation assembly 40 may include any suitable drive mechanism and motor. In embodiments, translation assembly 40 includes one or more suitable motors and drive mechanisms, such as, for example, suitable servo motors and endless belts, for selectively reciprocatingly moving transducers 21, 22 along the X-axis and Y-axis, and in at least some embodiments, along the Z-axis. In embodiments, each motor of translation assembly 40 is in electrical communication with controller 30 such that controller 30 may be used to control the movement of transducers 21, 22 via translation assembly 40. In embodiments, controller 30 may be programmed to cause translation assembly 40 to move transducers 21, 22 over at least one predetermined measurement path.

[0041] In embodiments, the translation assembly 40 may have a drive mechanism having different configurations, such as, for example, a screw or a rack and pinion arrangement. In embodiments, any suitable motor may be used.

[0042] Controller 30 is in communication with transducers 21, 22 to receive respective ultrasonic signals from these transducers. In embodiments, the controller may be in operative communication with these transducers via any suitable technique, such as, for example, being hardwired to transducers 21, 22. In other arrangements, wireless connection techniques or any suitable connection technique may be used, as would be understood by one of ordinary skill in the art. In embodiments, controller 30 is programmed to determine bond strength values ​​for mat-coated cementitious board sample 25 using the ultrasonic measurement data generated by transducers 21, 22.

[0043] In an embodiment, the controller 30 is programmed with a mat-coated cementitious board analysis application including a board bond measurement program stored on a non-transitory computer-readable medium 71. The mat-coated cementitious board analysis application is configured to operate the system 20 to determine bond strength values ​​of the mat-coated cementitious board specimens 25 using ultrasonic signals from the at least one non-contact ultrasonic transducer 21, 22.

[0044] In an embodiment, the controller 30 is configured to control the translation assembly 40 to selectively move the transducers 21, 22 in the XY plane over the analysis field. In an embodiment, the controller 30 is configured to move the carriage 55 along the X rail 54 to move the transducers 21, 22 along the X axis, and to simultaneously move the transducer arms 52, 53 along the Y axis by moving the plate 58 along the Y rail 57 to move the transducers 21, 22 along the Y axis to cover the analysis field.

[0045] In an embodiment, the controller 30 is configured to adjust the distance between the first transducer arm 52 and the second transducer arm 53 to bring the transducers 21, 22 within a desired distance of the matte facings 31, 32 of the sample 25 (see also FIG. 3 ). In an embodiment, the controller 30 is in operative relationship with a vision system to facilitate automated positioning of the transducer arms 52, 53 relative to a given board sample 25 supported on a support fixture 35.

[0046] In an embodiment, the controller 30 is in operative communication with the ultrasonic transmitting transducer 21 and the ultrasonic receiving transducer 22 to operate the transducers 21, 22 and receive ultrasonic data from these transducers. In an embodiment, the controller 30 is programmed to collect data from the ultrasonic transducers 21, 22 to evaluate the bond strength of the specimen 25 and display the results on the display device 72. In an embodiment, the controller 30 is programmed to pass ultrasonic pulses from the ultrasonic transmitter 21 through the board specimen to the ultrasonic receiver 22 and perform an ultrasonic analysis of the board specimen 25 based on the ultrasonic signals received by the controller 30 from the transducers 21, 22.

[0047] The controller 30 may be provided with an internally integrated transmitter transducer excitation mechanism or may have an external transmitter transducer excitation mechanism in operative arrangement. In embodiments, the excitation mechanism may be any suitable mechanism compatible with the transducers 21, 22 of the system 20, such as, for example, a pulser. The controller 30 may be provided with an internally integrated receive transducer amplification mechanism or may have an external receive transducer amplification mechanism in operative arrangement. In embodiments, the receive transducer amplification mechanism may be any suitable mechanism compatible with the transducers 21, 22 of the system 20, such as, for example, a receiver amplifier. The controller 30 may include or be in operative arrangement with an analog-to-digital transducer and a logic unit having software programmed into the controller 30. The controller 30 may be any suitable controller, such as, for example, a programmed microcontroller including a CPU. The controller 30 communicates with the components of the system 20 using any suitable technique, such as, for example, wiring using leads.

[0048] The controller 30 can be in communication with the movement assembly 40 and the transducers 21, 22. In an embodiment, the controller 30 is programmed with a mat-coated cementitious board analysis application stored on a non-transitory computer-readable medium 71. In an embodiment, the mat-coated cementitious board analysis application can be used to program the controller 30 to operate the evaluation system 20 and perform various board sample analysis protocols.

[0049] In an embodiment, the matt-coated cementitious board analysis application may include a control module configured to control the operation of the evaluation system 20. For example, in an embodiment, the controller 30 may be programmed to control the motion assembly 40 to direct the transducers 21, 22 over a predetermined measurement path.

[0050] In an embodiment, the mat-coated cementitious board analysis application may include a bond strength module configured to determine numerical bond strength values ​​for the mat-coated cementitious board sample 25 based on an ultrasonic measurement protocol. In an embodiment, the controller 30 is in communication with and receives ultrasonic signals from the transducers 21, 22. In an embodiment, the mat-coated cementitious board analysis application is configured to determine bond strength values ​​for the mat-coated cementitious board sample 25 using the ultrasonic signals received from the transducers 21, 22, which indicate signal strength attenuation measured over the transducer travel.

[0051] In an embodiment, the controller 30 includes a data storage device 73 configured to store mat-coated cementitious board sample data for use by and / or generated by the analysis application. In an embodiment, the controller 30 may be in operative relationship with a database in the data storage device 73 that includes ultrasonic data generated from the evaluation system 20 for a statistically significant number of samples 25 and destructive Z-joint separation pull-out tests of those samples 25 according to a predetermined destructive testing protocol, with both results quantitatively correlated. In an embodiment, the quantitative estimation is performed using i) the average signal intensity in the Z-joint test area, and ii) the attenuation, where the signal intensity is a function of the interfacial bond strength between the mat 31, 32 and the cementitious core 34. In an embodiment, the data set is normalized. In an embodiment, the mat-coated cementitious board analysis application is configured to use the database to determine the Z-joint separation pull-out force for a given sample 25 based on the ultrasonic data generated by the evaluation system 20 for the given sample 25.

[0052] In embodiments, controller 30 may comprise any suitable computing device, such as a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a personal organizer, a device controller, or a calculation engine within an appliance. In embodiments, controller 30 may comprise a collection of computing devices. In embodiments, controller 30 includes one or more input devices (e.g., a keyboard and mouse) and a display device (e.g., a monitor).

[0053] In embodiments, the mat-coated cementitious board analysis application may be stored on any suitable computer-readable storage medium 71. For example, in embodiments, the mat-coated cementitious board analysis application according to the principles of the present disclosure may be stored on a hard drive, floppy disk, CD-ROM drive, tape drive, zip drive, flash drive, optical storage device, magnetic storage device, etc.

[0054] In an embodiment, the mat-coated cementitious board analysis application includes a graphical user interface that may be displayed by the display device 72. The graphical user interface may be used to facilitate the input of commands and data into the mat-coated cementitious board analysis application by a user, and to display output generated by the mat-coated cementitious board analysis application.

[0055] In embodiments, evaluation system 20 may include other components and equipment as will be appreciated by those skilled in the art. For example, in embodiments, evaluation system 20 may include at least one laser sensor operatively arranged with controller 30 to help facilitate automatic positioning of transducers 21, 22 along the vertical Z-axis relative to sample 25, such that each transducer 21, 22 is disposed a predetermined distance from sample 25 along the vertical Z-axis. In embodiments, evaluation system 20 may include a commercially available ultrasonic testing unit, such as those available from The Ultran Group of State College, Pennsylvania.

[0056] In an embodiment, a mat-coated cementitious board analysis application according to the principles of the present disclosure may be configured to implement an embodiment of a mat-coated cementitious board testing protocol according to the principles of the present disclosure. In an embodiment, the mat-coated cementitious board analysis application may include other modules and features configured to perform one or more features of an embodiment of a method for evaluating a mat-coated cementitious board sample according to the principles of the present disclosure, as will be understood by one of ordinary skill in the art.

[0057] An embodiment of a method for evaluating a mat-coated cementitious board sample can be implemented using a system for evaluating a mat-coated cementitious board sample according to the principles of the present disclosure. In an embodiment, a mat-coated cementitious board sample 25 is supported by a support fixture 35 between a first XY plane and a second XY plane established by transducer arms 51, 52. An xy positioning stage 40 is controlled by a controller 30 to simultaneously move the transducers 21, 22 and generate a two-dimensional ultrasound profile of the sample 25 based on at least one ultrasound signal from the transducers 21, 22.

[0058] By analyzing ultrasonic data from transducers 21, 22 generated using a standardized measurement path on one mat-coated cementitious board sample 25 and comparing ultrasonic data from other mat-coated cementitious board samples using the same experimental parameters, at least in some embodiments, destructive Z-bond separation tensile testing of those samples according to a predetermined destructive testing protocol can be used to quantitatively measure the bond strength of the mat-coated cementitious board sample and compare it to other mat-coated cementitious board samples for use in quality control processes.

[0059] 3, there is shown a schematic diagram of a non-contact ultrasonic transmitter transducer 21 and a non-contact ultrasonic receiver transducer 22 suitable for use in one embodiment of a system for evaluation of mat-coated cementitious board samples constructed in accordance with the principles of the present disclosure. A mat-coated cementitious board sample 25 is disposed between the transducers along the Z-axis. The coupling medium for ultrasonic transmission through the sample is a gas such as air, either in an ambient environment or under elevated pressure.

[0060] In embodiments, evaluation system 20 may include any suitable ultrasonic transducer. For example, in embodiments, evaluation system 20 may include any suitable non-contact (air-coupled) ultrasonic transducer such that system 20 may be used to evaluate bond strength without contact with mat-coated cementitious board sample 25 as shown in FIG. 3. In embodiments, non-contact ultrasonic transducers 21, 22 may be similar to those described in U.S. Patent No. 6,311,573, entitled "Ultrasonic Transducer for High Transduction in Gases and Method for Non-contact Transmission in Solids," which is incorporated herein by reference in its entirety.

[0061] In an embodiment of the evaluation system 20, a second ultrasonic sensor 22 is used when the system 20 is operated in a transmit mode. This receive transducer 22 is capable of receiving the pulsed signal from the transmit transducer 21 through air alone, as well as through the sample 25 and air. The received signal is provided to a receiver that may be mounted internally within the controller 30 or as a separate receiver amplifier. In an embodiment, the received signal is processed using an analog-to-digital converter and then provided to a logic unit of the controller 30. The received signal strength to the transmitted signal strength emitted by the transmit transducer 21 may be compared by the controller 30 to determine an attenuated signal strength for use in determining the bond strength of the sample 25.

[0062] In embodiments, the evaluation system 20 may include a non-contact ultrasonic transducer configured to operate in a pulse-echo mode. In at least some such embodiments, the controller 30 may be programmed to operate the transmitted ultrasonic sensor 21 in the pulse-echo mode.

[0063] In an embodiment, a system for manufacturing a mat-coated cementitious board constructed according to the principles of the present disclosure includes a kiln, first and second conveyor sections, transducer arrays positioned such that the transducer arrays run along the width of the board and the board extends between the transducer arrays, and an evaluation system having a controller programmed with a mat-coated cementitious board analysis application. The mat-coated cementitious board has a cementitious core interposed between a pair of mat facers. The cementitious core is formed from an aqueous cementitious slurry.

[0064] Referring to Figure 4, there is shown a fragmentary schematic diagram of a system 200 for manufacturing a mat-coated cementitious board 225 constructed in accordance with the principles of the present disclosure. The system 200 for manufacturing a mat-coated cementitious board 225 includes a cutting station 201, a kiln 202, a conveyor 205, and a board bond measurement system 220. The mat-coated cementitious board 225 has a pair of mats 31, 32 bonded to a cementitious core 34 such that the cementitious core 34 is sandwiched between the pair of mats 31, 32, as shown in Figure 3. The cementitious core 34 is formed from an aqueous cementitious slurry.

[0065] 4 , the mat-coated cementitious board 225 extends along the machine direction 210 of the system 200, with the mat-coated cementitious board extending along a longitudinal X-axis and a transverse Y-axis perpendicular to the machine direction 210. In an embodiment, a cutting station 201 is disposed upstream of the kiln 202 along the machine direction 210. The cutting station 201 includes a knife configured to periodically cut the mat-coated cementitious board 225 along the cross-machine direction, i.e., the transverse Y-axis, to define a series of board segments as the mat-coated cementitious board 225 moves along the machine direction 210 past the cutting station 201. In an embodiment, any suitable known cutter configuration can be used, such as, for example, a rotary knife. In an embodiment, the cutting station 201 is disposed downstream along the machine direction 210 from the forming station a suitable distance based on the line speed to allow the aqueous cementitious slurry to hydrate and set. The forming station may be disposed downstream along the machine direction 210 from a suitable wet end where the aqueous cementitious slurry is formed and the mat(s) are applied.

[0066] In an embodiment, kiln 202 is disposed downstream of cutting station 201 along machine direction 210. Kiln 202 is configured to remove excess water from the aqueous cementitious slurry. In an embodiment, an additional cutting station may be provided downstream of kiln 202, where the board segments are further cut into shorter boards. In an embodiment, any suitable commercially available kiln may be used, as would be understood by one of ordinary skill in the art.

[0067] The conveyor 205 is configured to transport the mat-coated cementitious board 225 away from the kiln 202 along the machine direction 210. The conveyor 205 includes conveyor sections 211, 212 defining upstream and downstream support surfaces, respectively. The upstream and downstream support surfaces 211, 212 extend both along the machine direction 210 and the transverse Y-axis. The upstream and downstream support surfaces 211, 212 are in a discontinuous relationship with each other such that an unsupported span is defined therebetween along the machine direction 210 in which the transducer arrays 221, 222 are disposed so that the cementitious board can pass therebetween along a vertical Z-axis perpendicular to both the machine direction 210 and the transverse axis 230. In an embodiment, the transducer arrays 221, 222 may be disposed downstream from the kiln along the machine direction 210.

[0068] The mat-coated cementitious board 225 is supported on a first conveyor section 211 and a second conveyor section 212 downstream of the first conveyor section 211 so that the board 225 can be transported across a system 220 for evaluation of the mat-coated cementitious board 225, which includes a non-contact ultrasonic transmitter transducer array 221 and a non-contact ultrasonic receiver transducer array 222.

[0069] In an embodiment, board bond measurement system 220 comprises an evaluation system according to the principles of the present disclosure, including a controller programmed with a mat-coated cementitious board analysis application as described above and in operative communication with arrays 221, 222. Arrays 221, 222 are configured to span the width of board 225 measured in a transverse Y-axis perpendicular to the machine direction 210 in which conveyor sections 211, 212 transport mat-coated cementitious board 225 (see FIG. 5 ).

[0070] Board bond measurement system 220 includes a non-contact ultrasonic transmitter transducer array 221, a non-contact ultrasonic receiver transducer array 222, a controller 230, a non-transitory computer-readable medium 271, a data storage device 273, and a display device 272. Non-contact ultrasonic transmitter transducer array 221 and non-contact ultrasonic receiver transducer array 222 are disposed in an unsupported span between conveyor sections 211, 212 such that transducer arrays 221, 222 extend along a transverse Y-axis. In an embodiment, controller 230 is programmed to control transducer arrays 221, 222 and to receive signals from these transducers indicative of ultrasonic signals emitted by transmitter transducer array 221 and received by receiver transducer array 222 after passing through mat-coated cementitious board 225. Non-transitory computer-readable medium 271 carries a board bond measurement program. The controller 230 is configured to execute a board bond measurement program contained in a non-transitory computer readable medium 271 to determine board bond strength values. The data storage device 273 is in operative communication with the controller 230 and is configured to store board bond data generated by the controller 230.

[0071] The transducer arrays 221, 222 are disposed in a spaced apart relationship along a vertical Z-axis that is perpendicular to both the machine direction 210 and the transverse Y-axis, such that the mat-coated cementitious board 225 is adapted to move along the machine direction 210 from the upstream support surface 211 to the downstream support surface 212 and pass between the transducer arrays 221, 222 along the vertical X-axis.

[0072] The ultrasonic transmitter transducer array 221 is configured to emit ultrasonic signals from the ultrasonic transmitter transducer array along a vertical Z-axis such that the ultrasonic signals pass through the mat-coated cementitious board 225 and are received by the ultrasonic receiver transducer array 222. The ultrasonic receiver transducer array 222 is configured to transmit ultrasonic receive signals from the ultrasonic receive transducer array to the controller 230. The ultrasonic receive signals indicate the intensity of the ultrasonic signals received by the ultrasonic receiver transducer array 222 from the ultrasonic transmitter transducer array 221.

[0073] In an embodiment, the ultrasonic receiver transducer array 222 is configured to substantially continuously transmit ultrasonic reception signals to the controller 30. In an embodiment, the ultrasonic transmitter transducer array 221 is configured to continuously emit ultrasonic signals, which includes emitting pulse signals of a given period at a regular frequency.

[0074] In embodiments, evaluation system 220 may include any suitable ultrasonic transducer array. For example, in embodiments, evaluation system 220 may include any suitable non-contact (air-coupled) ultrasonic transducer such that board bond measurement system 220 may be used to evaluate bond strength without contacting mat-coated cementitious board 225 as it moves along machine direction 210, as shown in FIG. 4. In embodiments, non-contact ultrasonic transducers 221, 222 may include transducers similar to those described in U.S. Patent No. 6,311,573, entitled "Ultrasonic Transducer for High Transduction in Gases and Method for Non-contact Transmission in Solids," which is incorporated herein by reference in its entirety.

[0075] The controller 230 is in operative arrangement with the ultrasonic receiver transducer array 222 to receive ultrasonic receive signals from the ultrasonic receiver transducer array 222. The controller 230 is in operative arrangement with the non-transitory computer readable medium 271 such that the controller 230 is configured to execute a board bond measurement program contained on the non-transitory computer readable medium 271.

[0076] In an embodiment, the controller 230 is in communication with the ultrasonic transmitter transducer array 221 and receives ultrasonic transmit signals from the ultrasonic transmitter transducer array 221. The ultrasonic transmit signals indicate the strength of ultrasonic signals emitted by the ultrasonic transmitter transducer array 221 due to interaction with the mat-coated cementitious board 225. In an embodiment, the controller 230 is programmed to determine a numerical bond strength value of the mat-coated cementitious board 225 based on the ultrasonic transmit signals and ultrasonic receive signals received from the transmitter transducer array 221 and the receiver transducer array 222, respectively.

[0077] In an embodiment, controller 230 is programmed to operate transmitter transducer array 221 and receiver transducer array 222. In an embodiment, controller 230 includes a transmitter transducer excitation mechanism in operative arrangement with ultrasonic transmitter transducer array 221 and a receive transducer amplification mechanism in operative arrangement with ultrasonic receiver transducer array 222 to facilitate operative control of arrays 221, 222 via controller 230. In an embodiment, controller 230 includes an analog-to-digital converter for processing at least one of the ultrasonic transmit signals and the ultrasonic receive signals for use by a logic unit of controller 230 executing a board bond measurement program.

[0078] In an embodiment, the board bond measurement program includes a control module, a bond strength module, and a communication module. The control module is configured to control the operation of the ultrasonic transmitter transducer array 221 and the ultrasonic receiver transducer array 222.

[0079] The bond strength module is configured to determine a numerical bond strength value of the mat-coated cementitious board 225 based on the ultrasonic receive signals from the ultrasonic receiver transducer array 222. In embodiments, the bond strength module of the board bond measurement program is configured to determine a numerical bond strength value of the mat-coated cementitious board based on the ultrasonic receive signals and the ultrasonic transmit signals. In at least some such embodiments, the bond strength module of the board bond measurement program is configured to determine the numerical bond strength value of the mat-coated cementitious board 225 by determining a difference between the ultrasonic transmit signals and the ultrasonic receive signals to determine a signal strength attenuation value.

[0080] In an embodiment, the bond strength module of the board bond measurement program is configured to determine a numerical bond strength value of the mat-coated cementitious board by calculating an average signal intensity attenuation value over the length of the ultrasonic receiver transducer array along the cross-machine direction. In an embodiment, the bond strength module of the board bond measurement program is configured to determine a numerical bond strength value of each of the mats bonded to the core of the mat-coated cementitious board.

[0081] In an embodiment, the bond strength module of the board bond measurement program is configured to determine numerical bond strength values ​​for the mat-coated cementitious board using mat-coated cementitious board bond data stored in a database in data storage device 273. For example, in an embodiment, data storage device 273 includes a database of mat-coated cementitious board sample data including attenuation signal intensity data and destructive Z-joint tensile data for each sample. In an embodiment, the measured numerical bond strength values ​​of the mat-coated cementitious board 225 can be compared to the database to extrapolate the Z-joint tensile value of the board 225 without performing such destructive testing.

[0082] The communication module is configured to transmit a bond data stream to the display device 272. In an embodiment, the bond data stream includes numerical bond strength data determined by the bond strength module. In an embodiment, the board bond measurement communication module is configured to transmit an alert signal to the display device 272 when the numerical bond strength value determined by the bond strength module falls below a predetermined value. The display device 272 may emit any suitable visual and / or audible indicia configured to communicate to an operator that the numerical bond strength value determined by the bond strength module falls below a predetermined value.

[0083] The data storage device 273 includes a database configured to store mat-coated cementitious board bond data generated by the board bond measurement program. In an embodiment, the data storage device 273 includes a database configured to store mat-coated cementitious board bond data used by the board bond measurement program. In an embodiment, the mat-coated cementitious board bond data includes destructive Z-joint separation pull test data for several specimens and correlated signal intensity attenuation value data for several specimens. A bond strength module of the board bond measurement program can be configured to estimate a destructive Z-joint separation pull force value of the mat-coated cementitious board 225 by querying the database and comparing the signal intensity attenuation value determined by the bond strength module to the database of correlated signal intensity attenuation value data.

[0084] A display device 272 is in operative arrangement with the controller 230. In an embodiment, the display device 272 may comprise any suitable display device and may include a suitable graphical user interface for interacting with the board bond measurement program.

[0085] In embodiments, the system 200 for manufacturing the cementitious board 225 may include other components and stations, as would be understood by one skilled in the art. For example, in embodiments, the system 200 may include a wet end system, a forming station, a cutting station, a transfer system including a board inverter, a kiln, transducer arrays 221, 222, and a bundling and taping station.

[0086] In an embodiment of a method of manufacturing a mat-coated cementitious board according to principles of the present disclosure, a system for measuring board bond strength according to principles of the present disclosure is used to determine the extent to which at least one mat is bonded to a cementitious core within the cementitious board in an online manner during continuous production of the mat-coated cementitious board. In an embodiment, a method of manufacturing a mat-coated cementitious board according to principles of the present disclosure may be used with any embodiment of a system for manufacturing a mat-coated cementitious board according to principles discussed herein.

[0087] In one embodiment, a method of making a mat-coated cementitious board includes applying a mat to a cementitious core formed from an aqueous cementitious slurry. The mat-coated cementitious board is dried in a kiln to remove excess water from the aqueous cementitious slurry. The mat-coated cementitious board is conveyed along a machine direction away from the kiln. The mat-coated cementitious board extends along the machine direction and along a transverse axis perpendicular to the machine direction.

[0088] The mat-coated cementitious board is passed along the machine direction past a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array. The transducer arrays extend along a transverse axis and are in a spaced-apart relationship with one another along a vertical axis perpendicular to the machine direction and the transverse axis, such that the mat-coated cementitious board passes between the transducer arrays along the vertical axis. In an embodiment, passing the mat-coated cementitious board along the machine direction between the non-contact ultrasonic transmitter transducer array and the non-contact ultrasonic receiver transducer array includes positioning the transducer array along the vertical axis such that the transducer array is in a non-contact relationship with the mat-coated cementitious board.

[0089] Ultrasonic signals are emitted from the ultrasonic transmitter transducer array such that the ultrasonic signals pass through the mat-coated cementitious board and are received by the ultrasonic receiver transducer array. The ultrasonic receiver transducer array transmits the ultrasonic receive signals to the controller. The ultrasonic receive signals indicate the strength of the ultrasonic signals received by the ultrasonic receiver transducers from the ultrasonic transmitter transducers. In an embodiment, the ultrasonic signals are emitted from the ultrasonic transmitter transducer array and the ultrasonic receive signals are transmitted substantially continuously from the ultrasonic receiver transducer array to the controller.

[0090] The board bond measurement program stored on the non-transitory computer readable medium is executed using a controller to generate a numerical bond strength value for the mat-coated cementitious board based on the received ultrasonic signals. In an embodiment, executing the board bond measurement program stored on the non-transitory computer readable medium using the controller includes sending an alert signal to a display device when the generated numerical bond strength value for the mat-coated cementitious board falls below a predetermined value. In an embodiment, executing the board bond measurement program stored on the non-transitory computer readable medium using the controller includes displaying the numerical bond strength value for the mat-coated cementitious board on a display device via a graphical user interface.

[0091] In an embodiment, the method further includes periodically cutting the mat-coated cementitious board precursor to define a series of mat-coated cementitious boards as the mat-coated cementitious board precursor moves along the machine direction past the cutting station. The cutting station is disposed along the machine direction upstream of the non-contact ultrasonic transmitter transducer array and the non-contact ultrasonic receiver transducer array. In an embodiment, the method further includes passing each of the series of mat-coated cementitious boards along the machine direction between the non-contact ultrasonic transmitter transducer array and the non-contact ultrasonic receiver transducer array, such that the controller generates a numerical bond strength value for each of the series of mat-coated cementitious boards.

[0092] All references cited herein are incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and set forth in its entirety herein.

[0093] The use of the terms "a," "an," and "the" and similar referents in the context of describing the present invention (particularly in the context of the claims below) should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open terms (i.e., meaning "including, but not limited to"), unless otherwise noted. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually listed herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "etc.") provided herein is intended merely to better describe the invention and does not impose limitations on the scope of the invention unless otherwise recited in the claims. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0094] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors expect skilled artisans to adopt such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. 1. A system for manufacturing a mat-coated cementitious board, the mat-coated cementitious board having a mat bonded to a cementitious core, the cementitious core being formed from an aqueous cementitious slurry, the system comprising: a kiln configured to remove excess water from the aqueous cementitious slurry; a conveyor configured to transport the cementitious board away from the kiln along a machine direction, the conveyor including an upstream support surface and a downstream support surface, the upstream support surface and the downstream support surface both extending along the machine direction and a transverse axis, the transverse axis being perpendicular to the machine direction, the upstream support surface and the downstream support surface being in a discontinuous relationship with one another such that an unsupported span is defined therebetween; a board bond measurement system, a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array disposed on the unsupported span such that the transducer arrays extend along the transverse axis, the transducer arrays disposed in spaced apart relationship along a vertical axis, the vertical axis being perpendicular to both the machine direction and the transverse axis, such that the mat-coated cementitious board is adapted to move along the machine direction from the upstream support surface to the downstream support surface and pass between the transducer arrays along the vertical axis, the ultrasonic receiver transducer array configured to transmit ultrasonic receive signals from the ultrasonic receiver transducer array, the ultrasonic receive signals indicative of intensity of ultrasonic signals received by the ultrasonic receiver transducer array from the ultrasonic transmitter transducer array; a non-transitory computer readable medium containing a board bond measurement program; a controller in operative arrangement with the ultrasonic receiver transducer array to receive the ultrasonic receive signals from the ultrasonic receiver transducer array, the controller in operative arrangement with the non-transitory computer readable medium such that the controller is configured to execute the board bond measurement program contained in the non-transitory computer readable medium; The system for manufacturing, wherein the board bond measurement program includes a bond strength module configured to determine a numerical bond strength value of the mat-coated cementitious board based on the received ultrasonic signals.

2. a display device operatively arranged with the controller; 2. The system for manufacturing of claim 1, wherein the board bond measurement program includes a communications module configured to transmit a bond data stream to the display device, the bond data stream including the numerical bond strength values ​​determined by the bond strength module.

3. 3. The system for manufacturing of claim 2, wherein the board bond measurement communication module is configured to send an alert signal to the display device when the numerical bond strength value determined by the bond strength module falls below a predetermined value.

4. The system for manufacturing of claim 1 , wherein the ultrasonic receiver transducer array is configured to transmit the ultrasonic receive signals to the controller substantially continuously.

5. 2. The system for manufacturing of claim 1, wherein the controller is in communication with the ultrasonic transmitter transducer array to receive ultrasonic transmit signals from the ultrasonic transmitter transducer array, the ultrasonic transmit signals indicating strength of ultrasonic signals transmitted by the ultrasonic transmitter transducer array, and the bond strength module of the board bond measurement program is configured to determine the numerical bond strength value of the mat-coated cementitious board based on the ultrasonic receive signals and the ultrasonic transmit signals.

6. 6. The system for manufacturing of claim 5, wherein the bond strength module of the board bond measurement program is configured to determine the numerical bond strength value of the matt-coated cementitious board by determining a difference between the ultrasonic transmit signal and the ultrasonic receive signal to determine a signal strength attenuation value.

7. 7. The system for manufacturing of claim 6, wherein the bond strength module of the board bond measurement program is configured to determine the numerical bond strength value of the mat-coated cementitious board by calculating an average signal intensity attenuation value over a length of the ultrasonic receiver transducer array along the transverse axis.

8. a data storage device in operative communication with the controller, the data storage device including a database configured to store mat-coated cementitious board bond data for use by the board bond measurement program; 7. The system for manufacturing of claim 6, wherein the bond strength module of the board bond measurement program is configured to determine the numerical bond strength value of the mat-coated cementitious board using the mat-coated cementitious board bond data stored in the database of the data storage device.

9. 9. The system of claim 8, wherein the mat-coated cementitious board bond data includes destructive Z-joint separation pull-out test data of a number of specimens and correlated signal intensity attenuation value data of the number of specimens, and wherein the bond strength module of the board bond measurement program is configured to estimate a destructive Z-joint separation pull-out force value of the mat-coated cementitious board by querying the database and comparing the signal intensity attenuation value determined by the bond strength module to the database of correlated signal intensity attenuation value data.

10. A method for producing a mat-coated cementitious board using the system of any one of claims 1 to 9, comprising the steps of: applying a mat to a cementitious core formed from an aqueous cementitious slurry; drying the matt-coated cementitious board in a kiln to remove excess water from the aqueous cementitious slurry; conveying the matt-coated cementitious board along a machine direction and along a transverse axis perpendicular to the machine direction away from the kiln; passing the mat-coated cementitious board along the machine direction past a non-contact ultrasonic transmitter transducer array and a non-contact ultrasonic receiver transducer array, the transducer arrays extending along the transverse axis and in spaced relation to one another along a vertical axis, the vertical axis being perpendicular to the machine direction and the transverse axis, so that the mat-coated cementitious board passes between the transducer arrays along the vertical axis; emitting ultrasonic signals from the ultrasonic transmitter transducer array such that the ultrasonic signals pass through the matt-coated cementitious board and are received by the ultrasonic receiver transducer array; sending an ultrasonic receive signal from the ultrasonic receiver transducer array to a controller, the ultrasonic receive signal indicating a strength of the ultrasonic signal received by the ultrasonic receiver transducer array from the ultrasonic transmitter transducer array; using the controller to execute a board bond measurement program stored on a non-transitory computer readable medium to generate a numerical bond strength value for the mat-coated cementitious board based on the ultrasonic receive signals.

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