A calibration column, also named calibration pot, is a transparent, graduated cylinder installed on the suction side of a metering pump. It allows operators to visually measure and verify the actual flow rate of the pump by observing the liquid level change over time.
Calibration columns are a fast, easy, and economical means of checking flow rates of Milton Roy metering pumps. These devices allow operators to perform periodic monitoring and verification of pump flow rate, ensuring optimal performance and injection accuracy. They are also essential for verifying pump capacity after routine maintenance or troubleshooting dosing issues.
To help us prepare your quotation, please specify:
- The required calibration column size or your pump flow rate(s)
- Specifications of the fluid being injected or any preferred construction materials
- Your preferred connection size and type.
Available in Various Sizes
Offered in several sizes to match different metering pump capacities and application requirements.
Chemical-Resistant Materials
Built from robust, chemical-resistant materials to ensure long service life in demanding environments.
Accurate Flow Rate Verification
Graduated markings provide precise measurements for accurate calculation and confirmation of pump flow rates.
Quick & Easy Setup
Easily installs on the suction side of the pump without the need for special tools or complex procedures.
Ensure Correct Chemical Dosing
Confirms actual pump performance under real operating conditions, helping maintain dosing accuracy and compliance.
Cost-Effective Performance Checks
Reduces the risk of under- or over-injection while improving overall system reliability and operational efficiency.
The principle is simple:
- The column is filled with the fluid being dosed.
- When the pump operates, it draws liquid from the column.
- The operator measures the time it takes for the liquid level to drop between two graduations.
- Using this time and the volume difference, the actual pump flow rate (in l/h or GPH) is calculated.
This process helps verify that the pump is delivering the correct amount of fluid compared to its theoretical setting.
Sizing depends on:
- Pump capacity (maximum flow rate)
- Desired measurement accuracy
- Chemical properties (viscosity, density)
The calibration pot must have sufficient capacity to ensure that the measurement time is not too short. A minimum measuring time of 30 seconds is necessary.
To avoid calculations, Milton Roy recommends performing the measurement over periods of 36 seconds. The capacity of the measuring pot will then correspond to the hourly flow rate, expressed in l/h or GPH, divided by 100.
For instance, your pump has a flow rate of 40 l/h, you need to use a calibration column of:
40 l/h divided by 100 = 0.4 l/h
0.4l/h divided by 36 s = 0.5 l = 500 ml
Choose the next largest capacity for your calibration pot with a minimum volume of 500 ml.
Milton Roy offers several standard sizes to accurately calibrate your dosing pumps.
Choosing the right size ensures the level drop is measurable within a reasonable time (usually 30 - 60 seconds).
Step-by-step procedure:
- Isolate the pump suction from the main chemical tank and connect it to the calibration column.
- Fill the column with the chemical solution or fluid to inject to the top graduation mark.
- Start the pump at the desired stroke length and speed.
- Measure the time it takes for the liquid level to drop from one graduation mark to another (for instance from 100 ml to 50 ml).
- Calculate flow rate using the formula:
Real Flow Rate = Volume (ml) / Time (s) x 3600
That is why we always recommend to use multiple of 36 s to simplify.
Example: If 50 ml is injected in 36 seconds:
Real Flow Rate = 50 ml x 100 = 5,000 ml/h = 5 l/h - Compare this actual flow rate to the pump’s rated capacity and adjust settings if necessary.