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function calculateDosing() {
// Get input values
var flowRate = parseFloat(document.getElementById('flowRate').value);
var targetPpm = parseFloat(document.getElementById('targetPpm').value);
var sg = parseFloat(document.getElementById('specificGravity').value);
var hours = parseFloat(document.getElementById('operatingHours').value);
var cost = parseFloat(document.getElementById('chemicalCost').value);
// Validation
if (isNaN(flowRate) || flowRate <= 0) {
alert("Please enter a valid System Water Flow Rate.");
return;
}
if (isNaN(targetPpm) || targetPpm < 0) {
alert("Please enter a valid Target Concentration.");
return;
}
if (isNaN(sg) || sg 0.8).");
return;
}
if (isNaN(hours) || hours 24) {
hours = 24; // Default to 24 if invalid
}
if (isNaN(cost)) {
cost = 0;
}
// Calculation Logic
// Formula: L/hr = (Q_water_m3hr * ppm) / (1000 * SG)
// Derivation:
// 1 ppm approx 1 g/m3 (assuming water density 1000kg/m3, strictly 1g per 1000kg)
// Mass Chemical (kg/hr) = Flow(m3/hr) * 1000(kg/m3) * ppm * 10^-6
// Mass Chemical (kg/hr) = Flow * ppm / 1000
// Vol Chemical (L/hr) = Mass(kg/hr) / SG(kg/L)
// Vol Chemical (L/hr) = (Flow * ppm) / (1000 * SG)
var dosingLPH = (flowRate * targetPpm) / (1000 * sg);
// Convert to mL/min for pump setting
var dosingMLMin = (dosingLPH * 1000) / 60;
// Daily usage
var dailyUsage = dosingLPH * hours;
// Cost
var dailyCost = dailyUsage * cost;
// Display Results
document.getElementById('resLitersPerHour').innerText = dosingLPH.toFixed(3) + " L/hr";
document.getElementById('resMlPerMin').innerText = dosingMLMin.toFixed(1) + " mL/min";
document.getElementById('resLitersPerDay').innerText = dailyUsage.toFixed(2) + " Liters";
if (cost > 0) {
document.getElementById('resDailyCost').innerText = "$" + dailyCost.toFixed(2);
} else {
document.getElementById('resDailyCost').innerText = "N/A";
}
// Show result section
document.getElementById('resultsArea').style.display = "block";
}
Mastering Corrosion Inhibitor Dosing
Precise chemical dosing is the backbone of effective water treatment programs in boilers, cooling towers, and pipeline systems. The Corrosion Inhibitor Dosing Rate Calculator helps engineers and operators determine the exact flow rate required for their chemical dosing pumps to maintain target inhibitor residuals.
Why Accurate Dosing Matters
Maintaining the correct concentration of corrosion inhibitor is a balancing act. Deviating from the recommended range can have significant consequences:
- Under-dosing: Leaves metal surfaces vulnerable to oxidation, pitting, and general corrosion, leading to equipment failure and costly repairs.
- Over-dosing: Wastes expensive chemicals and can lead to secondary issues such as foaming, increased conductivity, or the formation of chemical deposits (scaling).
The Calculation Formula
To calculate the required dosing pump speed in Liters per Hour (L/hr), this calculator uses the following industrial standard formula:
Formula:
$$ Dosing Rate (L/hr) = \frac{Q_{sys} \times PPM}{1000 \times SG} $$
Where:
• Qsys = System Water Flow Rate (m³/hr)
• PPM = Target Concentration (Parts Per Million)
• SG = Specific Gravity of the Chemical (g/cm³)
Understanding the Inputs
System Water Flow Rate (m³/hr): This is the volume of fresh water (makeup water) or recirculating water entering the system that requires treatment. For open recirculating cooling towers, calculate based on makeup water flow for maintenance dosing.
Specific Gravity (SG): Not all chemicals weigh the same as water. Most corrosion inhibitors are denser than water, with an SG ranging from 1.1 to 1.4. You can find this value on the Safety Data Sheet (SDS) of your chemical product. Neglecting SG can result in under-dosing by 10-40%.
Pump Settings: mL/min vs L/hr
While engineering calculations are often done in Liters per Hour, the physical dial on a dosing pump is frequently calibrated in percentage or frequency, often verified via a draw-down calibration column in mL/min. Our calculator provides the mL/min value specifically to assist operators in calibrating their pumps accurately using a calibration cylinder.
Factors Affecting Dosing Efficiency
Even with a perfect calculation, real-world conditions vary. Always verify your calculations by testing the system water for chemical residuals (e.g., molybdate, phosphate, or specific polymer tracers). Factors such as "chemical demand" from existing corrosion, blowdown rates, and temperature fluctuations can consume the inhibitor faster than expected.