Automation and process protection
PLC Automatic Paper Machine Spray System
Coordinate nozzle travel, chemical metering, alarms, and paper-machine signals from one industrial control platform.
Make release-agent spraying part of the production sequence
A spray system should respond predictably when the paper machine starts, stops, or experiences a sheet break. If chemical delivery continues while the traverse is stationary, one area can be over-applied. If operators must coordinate several devices manually, settings can drift and abnormal conditions may be missed.
The Baozt PLC automatic paper machine spray system controls the traversing drive and electromagnetic metering pump as one process. It monitors nozzle travel, provides local operating controls, and can exchange permissive, run, stop, alarm, and status signals with the mill DCS. The detailed control philosophy is agreed during engineering so operators and automation teams know exactly how each state behaves.
Core control functions
- Variable-speed traverse: adjust nozzle movement to suit the application rate and working width.
- Adjustable travel range: movable limit switches define the active spray area.
- Motion supervision: travel-time logic identifies a stalled or abnormal mechanism.
- Pump interlock: chemical delivery stops when the drive is stopped or a fault is active.
- Machine-signal integration: run, stop, and sheet-break signals can control automatic operation.
- Local and remote control: operators can view status locally while the DCS supervises production operation.
Example operating sequence
| Machine condition | Traverse response | Metering-pump response |
|---|---|---|
| Run permissive available | Moves within the configured limits | Runs at the commissioned setting |
| Sheet break or process stop | Stops or moves to the agreed park position | Stops automatically |
| Travel timeout detected | Stops and reports an abnormal state | Stops to prevent fixed-point spraying |
| Local maintenance mode | Operates only under the defined local command | Follows maintenance interlocks |
| DCS communication unavailable | Uses the agreed safe state or authorized local mode | Uses the agreed safe state |
Integration starts with a clear control philosophy
Signal voltage alone is not enough to define a reliable interface. The engineering team confirms which system owns the start command, whether contacts are normally open or normally closed, what happens after power recovery, how alarms are acknowledged, and which conditions require a manual reset.
Baozt documents these decisions before commissioning and checks them with the mill’s electrical and automation teams. This reduces ambiguity during startup and gives maintenance personnel a consistent troubleshooting reference.
Industrial components and maintainable design
The cabinet combines PLC control, drive control, protection devices, power supplies, operator controls, and field connections. The mechanical system uses a protected cable chain and components selected for hot, humid paper-machine conditions. The spray assembly can be withdrawn for inspection, and critical settings are available through the operator interface.
Learn how automation supports the complete paper machine release agent spray system.
Frequently asked questions
Which operating signals can be interlocked?
Typical projects use machine run, stop, sheet-break, and permissive signals. Exact signal types, fail states, and timing are agreed with the mill automation team before commissioning.
What happens if the traversing motor stops?
The controller monitors motion and travel time. If an abnormal condition is detected, the motor and metering pump can be stopped together to avoid spraying in one fixed position.
Can operators change speed and spray range?
Yes. Traverse speed is adjusted by the drive, while movable limit switches define the operating range. Access to settings can be organized around the mill’s operating procedure.
Is local operation available when DCS communication is unavailable?
The control cabinet provides local operation and status indication. The agreed control philosophy determines how local and remote modes are selected and protected.
Plan the automation interface before installation
Send the available machine signals, control voltage, preferred operating sequence, and cabinet requirements. Baozt will prepare the automation scope with the mechanical proposal.