Diaphragm metering pumps provide precision and accurate dosing to many applications that require consistent flow. While precision and accuracy are very similar definitions referring to the quality of a measurement, they provide different indications. Precision refers to the degree to which a process or instrument will repeat the same value, while accuracy refers to the degree of closeness to a targeted value.
For applications requiring precise and accurate metering, Illinois Process Equipment, IPE, offers diaphragm metering pumps and flow meter solutions to ensure that your process flow capacity is exactly what it needs to be. Quality metering pumps should provide precision dosing regardless of fluid viscosities, temperature, or pressure, although these factors can affect the flow rate or accuracy of a pump’s performance.
Benefits of Metering Pumps over Centrifugal with Output Control
Metering pumps are a critical part of process equipment in many applications where precision and accuracy are required. Metering pumps provide added control with precise and accurate dosing over a centrifugal pump, for example, which can be set up to control output. Diaphragm metering pumps provide added control with precise and accurate flow, which is essential for a few critical reasons in many applications.
- Preventing production errors – when repeatable accuracy of +/- 1% is required for dosing chemicals or liquids to meet a specific formula, any flow out of spec will not provide the necessary function.
- Wasted product, wasted money – if a pump adds too much of a chemical or liquid, even if it does not affect the resulting solution, it will be wasting money, especially when continually pumping. This can be harmful to the environment as well as expensive.
- Wasted time, wasted money – it takes a significant amount of time to design a centrifugal pump with the proper instrumentation to try and match the precision and accuracy of a dosing diaphragm metering pump. Even with a centrifugal pump set with the appropriate controls, configuring automation and constant monitoring is extremely time-consuming. With the diaphragm metering pump, operators can walk away and have confidence that the specified dosing and flow will be achieved.
How to Ensure Accurate Dosing with Metering Pumps
There are many factors that affect the flow rate of metering pumps. Suppose a pump is operating with a pressure of 50 psi and metering 5 gallons of a particular chemical per hour. In that case, the same process will produce a lower flow rate closer to 4 ½ gallons per hour at a higher pressure of about 150 psi. While losing ½ a gallon per hour may not be significant, it could be crucial in certain applications. It is important that pump operators know exactly how to reach their desired output. Once your metering pump is calibrated and determined to produce the precisely desired output, it should perform with high accuracy of +/- 1% throughout the dependable service life of the pump. Grundfos SMART Digital pumps offer AutoFlowAdapt, a function that adjusts the pump speed to maintain a constant flow regardless of changes in pressure.
Understanding all the factors affecting flow rate for metering pumps will help you achieve precise and accurate dosing throughout your process. Some of these factors include:
- System pressure – system back pressure affects flow rate
- Flooded suction – if suction lift is required, this affects total output
- Length of piping – if extensive piping is necessary to meet the point of metering, this can affect flow
- Piping design – piping with multiple turns causes more friction and drag
- Size of piping – the size of pipe in relation to the pump’s inlet and outlet affect pump flow
- Viscosity
- Temperature
All of these factors can affect flow rate for metering pumps. You can ensure accurate and precise output by calibrating your pumps with calibration columns or a flow meter. Talk to your pumping and process equipment specialists at IPE to learn more.
IPE is the trusted Midwest supplier for pumping and process equipment solutions, offering high-quality pump equipment and full-service process design. We differ from other pump suppliers in our technical ability and responsiveness to customer needs. Contact us to learn more about achieving desired precision, accuracy, and flow rate with quality diaphragm metering pumps.
