A method of firing a pulverized fuel-fired steam generator furnace wherein a mixture of recirculated cleaned flue gas and air is supplied to the mill for drying the pulverized fuel in the mill and transporting the pulverized fuel to the furnace. The volume flow rate of the gaseous mixture of recirculated flue gas and air is controlled in response to the feed rate of fuel to the mill to maintain a mixture to fuel ratio in the transport stream of about but not less than 1.5. The volume flow rate of recirculated flue gas with respect to the volume flow rate of air is controlled to maintain the oxygen content of the gaseous mixture at a level of at least 12% by volume and preferably in the range of 12 to 15% by volume.

Method of firing a pulverized fuel-fired steam generator

A fuel injection system (10) for a two-stroke cycle engine comprising an air mainfold (80); a throttle valve (82); a fuel injector (92); a fuel supply system including a fuel pump (112); a battery voltage sensor (134); an air temperature sensor (136); an engine speed sensor (140); a timing sensor (142); a barometric pressure sensor (144); a throttle position sensor (146); a first data processor (171); for receiving and processing sensing signals for determining fuel injector duration and timing and fuel pump operating speed; a first data processor temperature sensor (176) for sensing the relative temperature of certain electronic components in the first data processor; a heater (174) operatively associated with the first data processor (171) electronic components for selectively heating the electronic components; and a second data processor (173) operable independently of the first data processor (171) for receiving an electronic component temperature sensing signal and for generating a control signal to the heater (174) responsive thereto for heating the components when the temperature thereof is below a predetermined minimum value.

Two-cycle engine with electronic fuel injection

An apparatus and method for extruding, cooling and cutting can include an extruder for producing an extrudate which can be fed through appropriate sizing, support and cooling devices, which can include a vacuum chamber, cooling chamber, and calibrators, which can have internal cooling passageways. The apparatus can also include a cutting blade, a programmable temperature controller for controlling the temperature of the extrudate prior to being cut by the cutting blade, and a temperature sensor, which can be positioned near the cutting blade and provide feedback to the temperature controller. The method can include sensing the temperature of the extrudate, at a point near the cutting blade, after it is fed through the sizing, support and cooling devices and before being cut. Such feedback can be used to control the temperature of the extrudate such that the extrudate is maintained within a desired range of temperature as it is cut. The temperature controller can automatically cool and maintain the extrudate within a desired range of temperatures using the temperature feedback at the point near the cutting blade. Where calibrators are used the apparatus can include additional temperature sensors at different sides of a multi-sided extrudate at a point near where the extrudate exits the calibrator. Such additional temperature feedback can be used by a temperature controller to adjust the temperature of the extrudate, and also at different surfaces of a multi-sided extrudate.

Apparatus and method for producing and cutting extruded material using temperature feedback

A simple and efficient process and automated system is provided for controlling the mixing of polymeric material and additive materials in an internal mixer to provide quality products and batch to batch product uniformity. Real time mixing temperature profiles of a plurality of good quality batches of the same product are developed. The profiles are then superimposed or averaged to produce a real time temperature curve with maximum and minimum temperature tolerance limits, thus providing a range of batch temperatures that are allowable in real time during the mixing cycle. A process control system is programmed to store the range of allowable temperatures and to signal a mixer control to change at least one of the rotor speed and the ram pressure when the real time batch temperature falls outside the reference temperature range for a predetermined period of time.

Dynamic mixer control in plastics and rubber processing

An apparatus for controlling a heating temperature, especially for heating a resin in a injection mold machine, a extruder and the like, includes a control device for controlling a heating means and the state of a heated barrel and a condition compensating device for issuing a compensation input to the heaters respectively in response to a reset of the control device, depending on the kinds of resin materials and molding conditions so as to prevent insufficient moldability in the injection mold machine and a deterioration of resin.

Apparatus for controlling a heating temperature

Power plant boiler fuel demand is transmitted as a coal feeder speed demand to a coal pulverizer control. A speed controller operates the feeder in accordance with the speed demand, and a position controller for a hot coal transport air damper positions the hot air damper to hold the mill outlet temperature to a setpoint value and to increase or decrease damper position in accordance with a feedforward signal representing the feeding speed demand. A position controller for a cold air damper regulates the total primary air flow to a value needed for safe and smooth transport of the pulverized coal to the boiler burners, and it accordingly acts as a process trim on the feedforward control applied by the hot damper controller.

Control for a power plant coal mill pulverizer having feedforward damper positioning

An arrangement for controlling the process temperature in an industrial process involving an extruding operation includes a summing element which sums the difference between the process temperature and a setpoint temperature with the rate of change of the process temperature and conveys this sum to a proportional and integral controller so that the output thereof acts in an inverse manner with the process temperature. This output of the controller is summed with the change of temperature rate which has been fed forward, to generate a demand signal. The demand signal is shaped and compared to a ramp waveform to generate a variable frequencey pulse for controlling a heating and/or cooling device associated with the extruding device. A change of speed rate can also be summed to form the demand signal.

William J. Smith

Papers

Control for a power plant coal mill pulverizer having feedforward damper positioning

Temperature control arrangement for an extruding process