Machine Control Case Studies

Case Study 101: Servo Industry Sector: Machine Control • Fiberglass Fiberization

New Technology Applied:

  • Allen Bradley ControlLogix
  • Allen Bradley Servo Drives
  • AMCI Encoders
  • Rockwell RSView 32 SCADA System

Project Description:
Staneco Corporation designed a fiberglass insulation machine which operated faster and more efficiently than the old equipment. Four fiberizer units deposited fiberglass on a moving conveyor. Any three could be used or all four depending on the type of insulation being made. The fiberizers were pivoted and deposited the fiberglass in a sine wave pattern. The pivot speed and conveyor speed were all adjustable depending on the product and stored recipes. To make uniform fiberglass, the pattern on the conveyor had to be adjusted. The phase angle of each pivoting fiberizer had to be calculated (frequency of pivot and conveyor speed both affect the phase angle). The information was used to control servo motors which controlled the motion of the pivot.

Project Outcome:
The key to successful resolution of this process problem was deciphering the complex relationship between belt speed and controlling the deposition sine wave of the fiberizer. The result was improved consistency, quality of product, and higher production rates.

Case Study 114: Extruders Industry Sector: Machine Control • PVC Compounder System

Technology Replaced:

  • Relay Panel

New Technology Applied:

  • Allen Bradley SLC 500
  • Allen Bradley PanelView

Project Description:
Staneco Corporation designed a control system to produce batches of compounded PVC. The system automatically weighed out batches of PVC resin and calcium carbonate. The material was conveyed with a pneumatic conveying system into a compounder drum. The drum was rotated and heated with the temperature being monitored. A liquid stabilizer and additional chemicals were automatically added to the mix when the temperature reached predetermined temperatures. At the end of the cycle, the material was unloaded into a cooling drum until it was cool enough to be transported into a storage silo. The material was then automatically distributed to several lines of extruders based on demand from the extruders.

Project Outcome:
The new control system eliminated repeat failures which were greatly impacting production and quality.

Case Study 110: Blending Industry Sector: Machine Control • Alloy Blending Machine

Technology Replaced:

  • Obsolete relay pane

New Technology Applied:

  • Allen Bradley MicroLogix 1500
  • Allen Bradley PanelView
  • AMCI Stepper Motor

Project Description:
Staneco Corporation designed controls for a machine that produced alloys in small batches. There were 20 recipes for different alloys. The cycle started by purging the chamber of air followed by gases being introduced into the chamber. The metal was heated to the required temperature by an induction heater. When at temperature, the crucible was then tilted in steps at different speeds using a servo motor to pour the metal into a mold. The crucible was then returned to the home position and atmospheric pressure was re-introduced. Temperatures were recorded on an electronic chart recorder.

Project Outcome:
The new control system provided increased reliability along with a more efficient operator interface.

Burner Management Case Studies

Case Study 122: LNG Industry Sector: Burner Management • Vaporizer Control System

Process or Machine Automated

  • submerged combustion vaporizer control systems

New Technology Applied:

  • GE Fanuc 90-30 series PLC
  • GE QuickPanel HMI
  • Wonderware Intouch SCADA

Project Description:
Staneco Corporation designed controls for multiple liquefied natural gas vaporizers for use in a re-gasification process at a peak shaving facility. Each vaporizer contained a large burner that heated a water bath for the evaporation process. Two PLC systems were utilized for control of each vaporizer; one system for burner management as required per the NFPA and one system for other process controls. All units had automatic ignition and bath temperature control. In addition to the gas control required to operate under normal conditions, interlocks were added to safely handle alarm conditions. Each control system provided feedback to the plant DCS.

Project Outcome:
The addition of these peak shaving units enabled the plant to meet the critical requirements of peak consumption periods. Operators praised the ease of use provided by the control system and the ability to make adjustments to ensure optimal performance.

Case Study 108: Ovens / Dryers Industry Sector: Burner Management • Conveyor Dryer

New Technology Applied:

  • Allen Bradley CompactLogix
  • Allen Bradley Panelview Plus HMI

Project Description:
Staneco Corporation designed a PLC panel with burner and motor controls for an industrial dryer. The drying process consisted of several stages which were heated by natural gas burners. Each stage had exhaust and combustion blowers which were started automatically by the PLC. The burner ignition was controlled by Honeywell flame relays. The material was carried through the dryer by a conveyor with VFD speed control. The temperature of the dryer stages was controlled by PID control loops in the PLC.

Project Outcome:
The ability to monitor many variables and store product recipes allowed for greater quality control and increased throughput.

Case Study 102: Stack Emission Control Industry Sector: Burner Management • Regenerative Thermal Oxidizers

New Technology Applied

  • Allen Bradley CompactLogix
  • Allen Bradley PanelView Plus HMI

Project Description:
Staneco designed controls for two thermal oxidizers used at a corn-to-ethanol plant to remove organic chemicals from discharged air. The oxidizers consisted of multiple gas burners which heated combustion chambers containing ceramic pellets. When the process gas is passed through the pellets, the organic chemicals are oxidized, neutralizing them. In order to prevent overheating of the ceramic pellets, a series of dampers were switched based on either time or chamber temperature. As the chambers were switched, some gas escaped unprocessed. To remove these gases, a purge operation was included to re-circulate the untreated gasses. The motors were controlled over Devicenet which included two VFDs. Temperatures and operation of the valves are monitored and alarmed. Data was made available to the plant DCS system.

Project Outcome:
System met and exceeded the required emission acceptable limits. The process also helped minimize fuel consumption.

Case Study 121: Ovens / Dryers
Industry Sector: Burner Management • Ceramic Sintering Furnace

New Technology Applied:

  • Allen Bradley CompactLogix
  • Rockwell RSView 32 SCADA System

Project Description:
Staneco Corporation designed a sintering oven to produce special purpose ceramics. The process was temperature and time dependent. There were numerous recipes for the different ceramic products produced. The temperature of the furnace was ramped up over a predetermined time to a selected temperature. At various temperatures different gasses were introduced into the process. The flow rate had to be controlled. When the maximum temperature was reached, it was held for a selected time. The temperature was then ramped down once again controlling the gas flows. Since one of the gasses was hydrogen, special interlocking and monitoring had to be used to prevent dangerous situations. The gas flows and temperature over time were logged and put into an Excel file for record keeping and examination. The cycle typically lasted from 12 to 16 hours.

Project Outcome:
Client praised the flexibility of the new system and its enhanced data collection abilities resulting in improved quality control.