Abstract: Disclosed are an apparatus and a monitoring system and various methods for use in the drying of lumber that use disclosed apparatus. During drying lumber is arranged in multiple courses stacked one on top of the other with multiple wooden stickers substantially evenly spaced from each other between courses and extending across the full width of said stack. The present invention includes a special sticker for inclusion in place of one of the wooden stickers to monitor the AE from the stack and to ultrasonically excite the stack for other measurements. The special sticker in the simplest form, includes a body portion and an acoustic sensor with the body portion constructed of an acoustically conductive material that is sized similarly to a wooden sticker. Also disclosed is a monitoring system which includes a special sticker and signal processing and control electronics coupled to receive an AE signal from the special sticker for monitoring and controlling the drying cycle of the lumber.

Abstract: The technology used in the present invention is acousto-ultrasonics (AU), in which a transmitted signal, at a controlled frequency is injected into a specimen with one transducer and received at another location by another transducer, permitting evaluation of the condition of the material in the signal path. In the experiments that were made using the present invention, the material within the press was a particleboard mat having the signal injected into the edge of one platen and received at the edge of the second platen. The AU signal received at the second platen is initially in response to pressure changes in the mat and subsequently follows the progression of internal bonding of the material. Since the propagated wave through the mat reacts to resin curing during the last phase of pressing, changes in material or press variables are reflected directly in shifts of the curve received at the second platen.

Abstract: A composition, apparatus and method for making resin bonded composite pultruded products using a thermosetting resin is disclosed. The resin includes a condensation resin which has a high solids content. A pultrusion system includes reinforcing material supply, a pultrusion die adapted to be heated, injection device for injecting resin into the die, and pulling device for drawing product through the die. The method includes supplying strands of the reinforcing material to the die and grasping the strands with the pulling device, injecting a condensation-type monomer resin into the die to impregnate the reinforcing material within the die, and pulling the resin-impregnated strands through the die at a rate that permits the resin to condense to an essentially cured state by the time the composite product is withdrawn from the die. The die is a modular die such that various sections of the die may be selected as desired to change process parameters.

Abstract: The present invention is a composite pultruded product and the method for its manufacture. The product is made with a plurality of longitudinal glass roving strands. In addition, a cellulosic mat is used in association with the roving. The mat serves as a filler, or reinforcing filler, to ensure uniform resin distribution within the product even when the glass content is significantly reduced. The method can be carried out on convention pultrusion equipment with little or no modification. The cellulose fiber mats may be either air laid or wet laid and should have an ultimate moisture of 3% or less before being incorporated into the pultruded product.

Abstract: The invention is a method for the on-line nondestructive determination of the internal bond strength of composite panel products. The method involves impinging an ultrasound pulse against the panel by a first transducer and receiving a transmitted pulse at a second transducer. The received signal strength, temperature and panel thickness are entered into an algorithm from which the internal bond may be calculated. Preferably the receiving transducer is located on the opposite side of the panel and displaced somewhat from the first transducer. The inclusion of temperature and panel thickness as independent variables greatly improves the accuracy over that available from uncorrected ultrasound testing.

Abstract: The invention is a method for the on-line nondestructive determination of the internal bond strength of composite panel products. The method involves impinging an ultrasound pulse against the panel by a first transducer and receiving a transmitted pulse at a second transducer. The received signal strength, temperature and panel thickness are entered into an algorithm from which the internal bond may be calculated. Preferably the receiving transducer is located on the opposite side of the panel and displaced somewhat from the first transducer. The inclusion of temperature and panel thickness as independent variables greatly improves the accuracy over that available from uncorrected ultrasound testing.

Abstract: A vertical progressive lumber dryer has a plurality of vertically spaced functional zones through which lumber formed into units pass. Each unit rests atop a base and each layer of boards in the stack is separated by sticker means. Predetermined appropriate operating conditions are selected for the drying medium as well as other parts of the process. After a car has completed the last step within the dryer, it is removed and the dryed lumber sent for further processing.

Abstract: The present invention is a method for measurement of moisture in dielectric materials. It is particularly useful for lumber. In the preferred version, at least two alternating current signals whose frequencies differ by a factor of at least 10 are capacitively coupled to the material. The coupling electrodes are in bridge circuits whose unbalance is measured at each frequency. The temperature of the dielectric material is also determined. Bridge unbalance signals are separated and rectified and the voltages, as well as a temperature analog voltage, are entered into a microprocessor programmed with a suitable algorithm to calculate a temperature corrected moisture value. The method overcomes significant inaccuracies in moisture readings due to temperature dependency.