What Is an Automatic Dosing System?
Quick answerAn automatic dosing system starts, stops and modulates a metering pump in response to time, flow, equipment pulses or water-quality/process measurements, delivering chemicals to the required point. It is an integrated system—not a single dosing machine—comprising a chemical tank, mixer, pump, valves, sensors, controls and safety devices.
Source:Official HOLY-AN Website｜Publication arrangement: Good Luck Device 0523.tw｜
Commonly used in PCB wet processes, cleaning, neutralization, water treatment and chemical processes. HOLY-AN also supplies developing neutralizers, cleaners, defoaming agents and other products. The system should be designed according to the actual liquid and tank conditions.
Four control strategies
| way | Applicable situations | Design focus |
|---|---|---|
| Timing/batch | Fixed cycle or fixed batch replenishment | Use experiments to establish single volume, set upper limits and prevent accidental touches. |
| traffic ratio | Add in the same proportion as the processing flow | Flowmeter signal, pulse wave magnification and low flow accuracy |
| Process pulse/amp hour | Supplement based on equipment output or plating load | Signal isolation, accumulated value and shutdown reset logic |
| Sensing feedback | Adjust according to targets such as pH, ORP, conductivity, etc. | Sensor calibration, hybrid delay, deadband and alarms |
System Components and Materials of Construction
- Storage and mixing:Tank volume, liquid level, dosing method, risk of settling or crystallization.
- Dosing pump:Flow range, back pressure, accuracy, pump head and diaphragm material.
- Pipeline valves:Bottom valve, filter, check, back pressure, pressure relief and injection port to avoid siphon and backflow.
- Sensing control:Flowmeters, pH/ORP/Conductivity, PLC/HMI, Recipes, Trends and Alerts.
- Safety facilities:Secondary containment, low-level shutdown, high-limit trip, ventilation, labeling and required personal protective equipment.
Verify every wetted material against the chemical concentration and operating temperature; a generic chemical name is not sufficient for compatibility selection. Provide the latest SDS before design, and confirm the final arrangement against site EHS requirements.
Selection, commissioning and maintenance
- Confirm the normal/minimum/maximum dosage and system back pressure, and allow the pump to work within the adjustable range.
- Confirm the compatibility, crystallization, volatilization, foaming and sedimentation of the liquid, and determine the mixing and piping.
- Design the sensing points and injection points to allow sufficient mixing time to avoid overdose caused by feedback delay.
- During commissioning, first use a safe test medium to verify flow direction, leaks, interlocks and alarms. Introduce the process chemical only after these checks pass and in accordance with the approved procedure.
- Establish cycles for sensor calibration, pump calibration, valve cleaning, hose/diaphragm replacement and leakage inspection.
Provide a process flow diagram, chemical SDS, control targets, flow range and site photographs. The Electronic Materials Department can then assess the application.
Contact HOLY-AN on LINEAutomatic Dosing System FAQ
Which Control Signals Can an Automatic Dosing System Use?
Common control inputs include timers, flow ratio, pulse count or ampere-hours, plus sensor feedback such as pH, ORP and conductivity. The correct strategy depends on process response time and the control objective.
Is a Larger Metering Pump Always Better?
No. Size the pump so its normal operating point remains within a stable control range. An oversized pump makes the minimum dose increment too large, increasing oscillation and overdosing risk.
Why Does a pH-Controlled Dosing System Oscillate?
Possible causes include sensor location, mixing lag, sampling interval, an oversized pump or unsuitable control parameters. First verify mixing and measurement reliability, then tune staged or pulse dosing.
What Chemical Data Should Be Provided with an RFQ?
Chemical name, concentration, density, viscosity, temperature, daily consumption, minimum and maximum instantaneous flow, tank and piping materials, and the safety data sheet (SDS).
