Diaphragm Type Metering Pumps

Automation Based on Proportioning

Injecting, metering, and dosing are all terms for adding repeatable and consistent amounts of liquid to another entity. What this section of the blog is addressing is proportioning, which is the term we use to differential the process from chemical injection, chemical metering, and chemical dosing.

Usually, not always, when you need a completely automated pumping system you need your dosing pump to pump an amount proportional to another flowing system. 1 part hydroxide for every 100 parts water as an example, so if the water picks up from 5 GPM to 8  GPM, the dosing pump needs to adjust from .05 to .08 GPM. This is why we have web pages dedicated to proportioning systems.

If you have an application which needs automatic proportioning in the pumping process, here is an idea of what all you can add to a Madden chemical injection pump to achieve true automation:

  • Add a variable frequency drive with multiple inputs and outputs. This gives you the capability of sending 4-20mA and other signals to the VFD to speed up and slow down the chemical pump’s motor to dose at a rate proportional to the main process flow rate.
  • Flow meters. These allow you to see and record the rate and/or total pump output so that the other instruments in your process can communicate with each other to keep the pump at the right proportion in relation to the main process flow rate.
  • PLC’s. This allows us to send you a package with pre-installed programs to control the flow rate at the proportion needed based on the Madden pump model being used.

Automation Based on Timing

We also know there are applications that call for automation via timing. Some applications call for you to meter the chemical into a process for a set amount of time and then turn off.

For the applications where we know exactly when the application will need to begin and end, we suggest using a simple timer with our chemical injection pumps. This is an inexpensive and fool-proof way to achieve accurate amounts of chemical dosing into a process running at intervals.

For applications where the need to begin and end dosing arises at inconsistent, or variable times throughout the process, Madden Pump along with the help of the experts at JK Industrial Controls can design a system for you to dose only when needed.
We want you to be certain that your chemical metering process will not waste the expensive chemicals you need to meter.

A few Common Applications

Where we see the need for these controls mainly lies within the following applications:

  • Water treatment where maintaining a certain PH balance is needed.
  • Dosing into an irrigation system, such as nitrogen for corn or oxide for algae and scale reduction in green houses.
  • Diluting or reusing a chemical liquid in a process by reading the ratio of the returning chemical/water solution and dosing more of the chemical, or water, when necessary.


No matter the process or application that needs automation, we want you to feel comfortable knowing that Madden Pump has the knowledge and resources to get you up and running, and then keep you running for a long time. Madden’s chemical metering pump design calls for very little maintenance as our durable pumps are made to work 24/7/365.

So if you need a proportioning system built or a chemical injection pump that can automatically run at set intervals, give Madden a call. We’re here to help.