Water Treatment Case Studies

Case Study 105: Polymer Systems Industry Sector: Water Treatment • Polymer Process Machine

New Technology Applied:

  • Allen Bradley ControlLogix
  • Allen Bradley PanelView Plus HMI

Project Description:
Staneco Corporation designed a control system for polymer mixing machines. Polymer is used in the process to remove particles from both drinking water and treated sewage. The system involved monitoring the level of a polymer tank. When the level dropped to a pre-determined point, a new batch of polymer was added. First water was added to a mixing tank to a pre-determined level. When the tank reached this level, a polymer powder was weighed and added. As the powder was added, a mixer started blending the water and polymer. The pre-determined polymer concentration was calculated. The mixture was then sent to a second mixing tank where more water was added to get the polymer concentration down to the required level. Finally the polymer was pumped into the final polymer tank. The system was set up to operate in two modes, demand batching and bulk batching; each having different control characteristics.

Project Outcome:
System allowed for customization of recipes enabling quality control of the product. HMI alarm indication reduced operator error and increased the machine life cycle.

Process Control Case Studies

Case Study 105: Polymer Process Industry Sector: Process Control • Polymer Process Machine

New Technology Applied:

  • Allen Bradley ControlLogix
  • Allen Bradley PanelView Plus HMI

Project Description:
Staneco Corporation designed a control system for polymer mixing machines. Polymer is used in the process to remove particles from both drinking water and treated sewage. The system involved monitoring the level of a polymer tank. When the level dropped to a pre-determined point, a new batch of polymer was added. First water was added to a mixing tank to a pre-determined level. When the tank reached this level, a polymer powder was weighed and added. As the powder was added, a mixer started blending the water and polymer. The pre-determined polymer concentration was calculated. The mixture was then sent to a second mixing tank where more water was added to get the polymer concentration down to the required level. Finally the polymer was pumped into the final polymer tank. The system was set up to operate in two modes, demand batching and bulk batching; each having different control characteristics.

Project Outcome:
System allowed for customization of recipes enabling quality control of the product. HMI alarm indication reduced operator error and increased the machine life cycle.

Case Study 114: Batching
Industry Sector: Process 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.

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.

Conveying Case Studies

Case Study 103: Bulk Industry Sector: Conveying • Scarfing / Crusher Conveyor System

Old Technology Replaced:

  • Antiquated Relay Panel

New Technology Applied:

  • Allen Bradley MicroLogix
  • Allen Bradley Component HMI

Project Description:
Staneco Corporation designed a crusher conveyor control system to replace an existing relay panel. The system consisted of conveying material through a series of conveyors and hydraulic crushers. Crushed material was then conveyed and separated by size and conveyed to different piles. Speed of the conveyor was controlled by VFD based on operator input. Safety interlocks were applied to prevent any possibility of injury. The system was able to operate in automatic, remote and manual modes. HMI displayed alarm conditions and location of fault events.

Project Outcome:
The combination of the PLC and HMI provided a more modernized system which increased throughput and minimized downtime while meeting all safety requirements.

Case Study 106: Pneumatic Industry Sector: Conveying • Pneumatic Conveying Systems

New Technology Applied:

  • Allen Bradley ControlLogix
  • Allen Bradley PanelView Plus

Project Description:
Staneco Corporation designed controls for multiple baghouse systems and hydrated lime injection systems used at multiple coal-fired power plants. The hydrated lime system had multi-point injection points and was used with fluid bed boilers. Hydrated lime is a proven alkaline reagent used to remove SO3 from the flue gas. Both pressurized and vacuum conveying was implemented. Blower motors, feeders, and rotary airlocks were controlled and monitored. Alarm conditions were monitored and control interlocks utilized allowing the system to operate safely.

Project Outcome:
Systems provided an effective and cost-efficient way to reduce emissions from the fluid bed boilers. The use of control interlocks and alarm monitoring kept the systems operating safe and increased the equipment’s performance.

Case Study 108: Manufacturing Industry Sector: Conveying • Conveyor Dryer

New Technology Applied:

  • Allen Bradley CompactLogix
  • Allen Bradley Panelview Plus HMI

Project Description Applied:
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 113: Material Handling Industry Sector: Conveying • Material Handling System

New Technology Applied:

  • Allen Bradley ControlLogix
  • Allen Bradley PanelView Plus HMIs

Project Description:
Staneco Corporation designed a system to deliver 400 to 1600 pound rolls of paper to printing presses using an in-floor chain conveyor. The system consisted of carts holding rolls of newspapers that traveled through the press room until a press operator needed a roll of paper; at which time the operator pressed a button diverting the new roll to the press. At the press the roll was removed, the empty cart detected and sent back to an area where it could be refilled. Filled carts were automatically merged back onto the main line. Special carts were used to remove waste such as the roll covering and empty spools. Full waste carts were diverted to the waste area, emptied, and automatically merged back to the main line. The critical functions included controlling the cart stops at the merge area and implementing a shutdown if a collision was about to occur at the merge point.

Project Outcome:
The implementation of the system reduced cart collisions thereby increasing operational safety and allowing quicker reloading of the presses.