A dosing system is more than a pump and a tank. This page walks the full design sequence — from the mass balance that sizes everything, through storage, make-up, pumping, injection, mixing and contact, to instrumentation, containment and the finished P&ID. Follow it in order and nothing important gets left out.
Everything downstream is sized from this.
Begin with the duty envelope: flow range and dose range. The mass balance fixes peak and minimum reagent rate, daily consumption and therefore tank, pump and delivery sizing.
Each component, in the order you should design it.
Bulk and/or day tank sized for delivery interval and buffer. Material rated for the reagent (HDPE, GRP, lined steel). Bunded to 110% of the largest tank. Level monitoring and high/low alarms.
Where neat strength is impractical (polymer, dilute acid/caustic), an ageing/dilution rig prepares the working solution. Polymers need controlled wetting and maturation time; see polymer dosing.
Type chosen for accuracy, turndown, viscosity and chemistry — diaphragm, peristaltic or progressive-cavity. Duty/standby for critical duties. See selection.
Calibration column for stroke checks, pulsation damper for smooth flow, pressure-relief valve, loading/back-pressure valve, isolation and non-return. Protects the pump and verifies output.
Injection quill delivering reagent to the pipe centreline, isolatable for maintenance, located where mixing follows immediately. Detailed on mixing & injection.
In-line static mixer or rapid-mix tank for dispersion, then contact volume sized for the reaction/CT requirement before the analyser or next process step.
Flow meter for pacing, analyser (pH/ORP/residual/turbidity) after the contact zone, controller and SCADA. Interlocks: low-level cut-out, leak detection, no-flow dosing inhibit. Loop design on control strategy; documentation on P&ID services.
Designed in, not bolted on.
No-flow inhibit (don't dose into a stopped stream), low-level cut-out (don't run a pump dry), and bounded control output (don't let a failed analyser drive a runaway dose).
Calibration column and a closed mass balance confirm the system delivers what the design intended — commission against the numbers, not by eye.
P&ID, functional design spec, then prove it on water.
Capture the design as a P&ID and functional description: every instrument, interlock and control mode. Commission by verifying pump calibration, confirming the mass balance closes, and tuning the control loop against live data. Hand over with an O&M manual and a maintenance schedule.
P&ID and documentation servicesFrom mass balance to commissioned P&ID. Give us the duty and the stream and we will deliver storage, pumps, injection, mixing, control and containment as an integrated, compliant package — skid-mounted or containerised.
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