Hello and welcome to our blog. On this occasion we would like to give you 7 tips that we believe are very important when choosing a metering pump and that can make it easier for you to make the final decision on which one to buy.
What is a metering pump for?
Metering pumps are used to inject a predetermined volume of liquid from one place to another within a specific time frame. Although they can be used to move any type of viscous liquid, as well as acids, bases and solvents, they can also be used in a variety of applications for wastewater treatment.
A metering pump can be modified to provide different flow rates. They are useful when a precise volume must be delivered, for example, when dosing chemicals for disinfection, filtration or coagulation. Chemical dosing rates can be easily modified according to process conditions.
They differ from pumps used for transfer applications in that the internal operating clearances are much narrower, which minimises internal fluid slippage. This also allows very precise and measured quantities of fluid to be metered and transferred.
As you can see, it is essential to keep in mind some useful tips for choosing a metering pump and to avoid some common mistakes.
What tips to consider when choosing a metering pump?
1. What application data can you collect?
Correct and complete application data for the metering pump is essential to ensure that the pump will perform correctly, with minimal maintenance. You can share the following information with the pump manufacturer to ensure you get the right pump for the job:
- Flow rate (minimum, normal, maximum)
- Inlet and outlet pressures (minimum, normal, maximum)
- Viscosity
- Temperature (minimum, normal, maximum)
- What type of fluid to be handled
- Whether solids are present and, if so, percentage, maximum particle size and hardness of the solids
- Motor data (phases, Hertz, voltage) and possible ATEX classification
2. What is the pump to be used for?
Inform your supplier about what you need to use the pump for, as they may have suggestions about which models and options will be most effective. It is important to identify all possible conditions under which the pump is required to operate, as it can be costly and difficult to solve a problem arising from overlooked application conditions. Be sure to note that the pump is to be used for a dosing job.
For even higher accuracy, your supplier may advise you to sacrifice the additional clearances applied to high viscosity pump parts at the cost of slightly higher power requirements. It is also important to note that high temperature applications have lower viscosities, so the slip factor must be considered if there is considerable differential pressure.
3. What lubricants do you need?
Many metering pumps, depending on their design and the pumping conditions in which they will operate, require lubrication for bearings and seals. These parts can be damaged if they run dry for even a short period of time, so ask your supplier about the lubrication needs of your pump.
4. Does your pump need auxiliary equipment upstream and downstream to improve its performance?
Some pumps may use strainers, isolation valves, pressure relief valves or calibration columns. Check with your pump manufacturer for the specific needs of your metering pump, such as the mesh size of the strainer or the setting of a pressure relief valve.
5. Confirm if your pump requires an external pressure relief valve.
Most positive displacement pumps require the installation of an external safety relief valve in the rising main. This is often an additional precautionary measure to protect the pump, especially if there is the possibility of a restriction in the piping, such as a clogged nozzle, strainer or isolation valve.
6. Do you need to store the pump for a long period of time?
If the pump is to be stored for a long period of time, or between uses, you may need to apply an oil coating to unpainted or machined surfaces, employ special packing methods or use special storage materials.
You may even need to schedule motor and pump shaft rotations, depending on the length of downtime. Be sure to communicate the expected downtime, so that the pump manufacturer can advise you on the most suitable pump for your needs and whether any maintenance will be required.
7. Before installing your pump, be sure to read the installation and operation manual and take note of the recommended mounting and piping practices.
Even if your metering pump is quite robust, incorrect installation, assembly or piping can affect its performance. Be sure to read and understand the manual to get it right or entrust your installation to a reputable professional.
Finally, consider the level of quality required. Metering pump accessories are very precise, so be sure to consider all of the above when selecting the right pump for a metering application.
If you would like our help, call our number. We have experts on hand to help you choose, install and maintain a wide range of equipment.
