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: 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: 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.