Abstract: A method and apparatus for controlling the state of a pneumatic actuator having a valve that connects the actuator to a supply pressure and a valve that connects the actuator to an exhaust pressure. The method involves closing the supply pressure and exhaust pressure valves, determining the current state of the pneumatic actuator, and then determining the difference between the current state and a desired state. The appropriate pressure valve to be opened and the period to be opened is then calculated based on pre-determined calibration data for the actuator which permits the end state of the actuator to be predicted. The appropriate valve is then opened for the calculated period to adjust the actuator to the desired state. The process is then repeated until the current state of the actuator is the desired state. A controller unit that uses the above method is also disclosed.

Abstract: A nozzle assembly for converting liquid from a liquid source into a spray flow using air from an air pressure source to atomize the liquid. The nozzle assembly comprises a housing having an air inlet for connection to the air pressure source, a liquid inlet for connection to the liquid source, and an outlet. A series of first air passages are formed in the housing for receiving air from the air inlet. The first air passages communicate with the outlet and are configured to generate a swirled air stream. A second air passage in the housing is also provided and is configured to generate a linear air stream. There is a liquid passage for receiving liquid from the liquid inlet. The liquid passage contracts to a reduced cross-sectional area adjacent the housing outlet. The first and second air passages and the liquid passage terminate in a common atomization zone adjacent the housing outlet where liquid flowing through the liquid passage is atomized into a spray pattern.

Abstract: A mounting system for removably mounting a sensor array adjacent the wire of a papermaking machine. The mounting system comprises an elongate base member formed with a tongue or groove with a corresponding interlocking groove or tongue formed on the sensor array adapted to be slidably received and retained by the elongate base member. The tongue and groove are dimensioned to permit relative movement of the sensor array with respect to the base member. An inflatable bladder is housed between the elongate base member and the sensor array and the bladder is adapted to be inflated to move the tongue and groove into a locked position to fix the position of the sensor array with respect to the elongate base member. This arrangement allows for easy and efficient removal of the sensor array when the bladder is unpressurized while providing reliable clamping when the bladder is inflated.

Abstract: A coat weight control system for applying coating to a paper sheet in a paper machine permits even coating across the sheet with less actuator force needed. The system applies a specified force profile on a coating blade and has a plurality of actuators spaced apart, the actuators each applying a load. A flexible backing bar is positioned on the coating blade having connections there along to the actuators, the backing bar having a plurality of keyhole slots between the connections, the slots spaced apart along the bar.

Abstract: Apparatus and method for controlling the size of a gap through which material is metered. The gap is defined by a rigid surface and a flexible surface connected to at least one actuator for deforming the flexible surface. A plurality of sensors are positioned along the rigid or flexible surfaces to detect the other of the surfaces and generate signals indicating its position. A computing unit in communication with the plurality of sensors processes the signals to generate a continuous gap measurement profile. The computing system also stores a pre-determined desired gap measurement profile. A control system in communication with the computing unit actuates the actuators to deform the flexible surface to adjust the gap measurement profile to correct any deviation from the desired gap measurement profile.

Abstract: A method for controlling the properties of a sheet of material to be manufactured on a sheet making machine using a network of intelligent actuators distributed across and down the length of the paper machine. The method includes the steps of measuring and acquiring properties data about the sheet of material and communicating the measured properties data as the data becomes available to the actuators that control the properties of the sheet of material. A control action for each actuator is calculated and implemented using a control model of each actuator's influence on the properties of the sheet so as to minimize the variation of the measured properties data from a desired target. The control action made at an actuator and the predicted changes in the measured properties based on the control model are also communicated to all the actuators.

Abstract: A process for determining shrinkage and alignment of the web in a sheetmaking machine having a plurality of actuators for controlling web parameters in the cross-direction. The process involves the steps of applying excitation to the actuators, collecting data regarding the change in cross-direction web properties due to the excitation of the actuators to determine a measured actuator response profile. A modeled actuator response profile is established and a best fit of the modeled actuator response profile to the measured actuator response profile is established to allow for determination of alignment and shrinkage parameters of the web based on the best fit modeled actuator response profile. The foregoing approach permits reliable identification of alignment and shrinkage within 10-20 data scans of the web, despite process noise, with improved accuracy when compared with conventional "bump" tests.

Abstract: A coupling member for joining a first article to a second article comprising first and second elongate arms that are pivotally connectable to a main housing via ball and socket joints. Each arm has one end formed for connection to one of the articles and the other end adapted to be engaged in the ball and socket joint. A locking system is also provided to lock the arms in position with respect to the main housing after the arms have been connected between the first and second articles to create a rigid connection between the first and second articles. The pivotable nature of the coupling member allows for a connection to be made between the first and second articles to be joined without the articles being in perfect alignment whereupon the locking system is applied to create a rigid link.

Abstract: A steam applicator to apply steam to a web passing by the applicator. The applicator is a main supply header and a plurality of profiling steam chambers to receive steam from the main supply header. The pre-heat chambers adjacent the profiling steam chambers. The flow of steam is controlled from the main supply header to each profiling steam chamber. At least one outlet in each profiling steam chamber allows a supply of steam from the applicator. The supply of steam from each outlet can be controlled. The apparatus is compact and has the virtue avoiding condensate dripper onto the web.

Abstract: An apparatus and method for controlling mass flow in an extrusion die provides cross-directional measurements of at least one property of an extrusion produced by the extrusion die, such measurements being made at a plurality of cross-directional locations that successively span the extrusion. The measurements are assembled to provide cross-directional profiles of the extrusion. A spatial-frequency splitter operates upon the cross directional profiles to separate selected spatial frequency component profiles from each cross-directional profile. A reference profile is provided for representing desired spatial frequency profiles. An error signal generator generates error signals representing the difference between the spatial frequency component profiles and the desired spatial frequency profiles and actuators control mass flow components of the extrusion die in response to the error signals.

Abstract: Apparatus for distributing a heating medium, such as steam or hot air, to a paper web or calendar roll in sheet making machinery includes a removable profile screen to permit easy cleaning and maintenance. The apparatus comprises an elongated chamber to receive steam or hot air from a supply source with a front wall adapted to receive a removable screen. The removable screen is flexible and defines at least a portion of the front wall conforming generally to the shape of the adjacent surface to be heated. The screen member has a plurality of apertures through which the heating medium is forced to heat the surface. The screen is removably mounted to the apparatus by clip members.

Abstract: A method for determining the cross-machine shrinkage or expansion profile of a travelling sheet produced in a sheetmaking machine between an upstream location and a downstream location. The method involves marking the sheet at the upstream location with an array of marks at measured, predetermined intervals in the cross-machine direction. The sheet is inspected in the cross-machine direction at the downstream location to measure the spacing of the array of marks. A shrinkage or expansion profile of the travelling sheet is developed based on the changes in the spacing between the array of marks at the downstream location. Apparatus for carrying out the method is also disclosed. The method and apparatus of the present invention permit rapid and precise determination of the sheet shrinkage or expansion profile to allow for better control of property variation across the sheet.

Abstract: An actuator converts rotational movement to linear movement and at the same time transmits a limited linear force without requiring slip clutches or the like. The actuator has an electric motor in a fixed housing with a drive shaft on a longitudinal axis. A drive gear, substantially free of backlash, is connected to the drive shaft and has an output connection to drive a drive nut with an internal screw thread on the rotary axis. An output shaft has an external screw thread engaging with the internal screw thread of the drive nut and moves linearly when the drive nut is rotated. A voltage control system allows the voltage to the motor to be set so that for a set voltage there is a predetermined longitudinal force on the output shaft.

Abstract: A process for transforming a plurality of data points n defining a high resolution profile for a parameter of a sheet material being manufactured into a low resolution profile for control of the parameter is disclosed. The process involves filtering the data points of the high resolution profile using an anti-aliasing filter function to create an intermediate profile and reducing the number of datapoints of the intermediate profile by an integer factor to create the low resolution profile to be used to control the parameter.

Abstract: A caliper profile control system for a paper machine provides reduced start up times after sheet breaks to bring the caliper profile across the sheet to within the desired limits. The method comprises the steps of scanning at predetermined intervals across the width of the paper sheet to monitor thickness error of the sheet from predetermined limits and change in the thickness error between the intervals, in each of a plurality of zones across the sheet. A control change signal is determined for each of the zones based on the error and the change in error using an exponential function of the magnitude of the error to maximize the change in the error and reduce integral action when the error is large. The control signal is used to reduce the error in each zone and the integral action is increased as the error decreases until the predetermined limits are met.