Diaphragm Type Metering Pumps

By nature, most chemical metering pumps, are positive displacement type diaphragm pumps. This is because repeatable and accurate output is crucial to chemical injection applications as wasted, excess chemical injection can ruin the process as well as cost you a lot of money. Positive displacement type diaphragm pumps have very repeatable and accurate outputs.

But to achieve this repeatable, accurate output, chemical metering pumps utilize a lot of moving parts, including the valve assembly with check ball valves, and the interior components that transfer the energy from either a solenoid or electric motor, to make the diaphragm reciprocate backwards and forwards.

These moving parts will inevitably wear out. Often times, chemical injection applications are an all day, all week, all year long type of application; and with cheaper, plastic, solenoid driven pumps, you may find yourself replacing these yearly, if not even more frequently.

Plastic, solenoid driven metering pumps offer the convenience of built in electronic controls and a relatively inexpensive initial cost, but they do not offer the best service life.

Repurchasing a new chemical dosing pump every year at $500-750 a unit certainly adds up.

Consider a metering pump that when simply looking at it, looks like it is made to pump all day long, all week long, for years on end. That is how Madden Pump designs their metering pumps.

Madden works hard to have our brand recognized as one of the most rugged and durable pumps available on the market, and to have customer service second to none.

Chemical injection pump with RUGGED and ROBUST internal parts, and heavy duty wetted end parts.

If you talk with our distributors, the first things they’ll say about the Madden pump is that it is robust like no others, and that our group here is awesome to work with. We’re very, very proud of this, and will touch on the latter a bit later in this article.
Madden chemical dosing pump

One of the first things you would notice in comparison from a Madden chemical metering pump to a plastic, solenoid metering pump, is the pump’s body. It’s a night and day difference.Madden metering pumps utilize an aluminum body and heavy duty interior drive parts. A solenoid driven pump is plastic, and has a magnet on the inside driving the diaphragm back and forth. This does make it lighter and easier to move, but a significant detriment to longevity of performance. Every part in the Madden pump is made of metal: from the electric motor, to the worm gear and sprocket, to the drive shaft, to the connecting rod, to the piston, and then finally to the diaphragm, and all internal parts are constantly operating in an oil bath. This is what you want if your chemical process calls for 24/7/365 operation.

Madden Pump JN series dosing pump diaphragmThe second most noticeable thing you’d likely notice when looking at a Madden metering pump, if sitting next to a standard solenoid driven, plastic metering pump, is a thick primary

diaphragm, next to an almost paper thin diaphragm. The diaphragms we use are up to a 1/4” thick. They’re like a tire. Arguably the most important piece in your chemical pump, the diaphragm which reciprocates back and forth, while contacting the process liquid, needs to be durable; otherwise, you’re looking at a headache of replacing this too frequently.

Hopefully, our design’s durability stands out now. But truly, don’t dismiss the last part of service life we mentioned, the service you get from us, and our family of distributors.

We don’t say this just to brag, it’s the most significant feature we can offer to separate us from the other pump manufacturers who can make solenoid pumps and heavier duty pumps.

We focus on offering great service because we take pride in it, because it’s easier for us to do day in and day out as a small manufacturer, and because, frankly, we need to in order to compete.

If you’ll entertain my metaphor here, let’s see if I can make this truly hit home:

Think of something you recently bought online that you put a little bit of thought in to. I’d venture to guess you had several tabs pulled up on your internet browser, bouncing back and forth between them as you compare product reviews, prices, features, etc. before finally selecting the specific item you want and from which company/website you preferred.

Personally, I most recently did this with a pair of training shoes. This was not a normal “repeat purchase” for me. I did not necessarily care what brand they were, I just wanted the best quality shoe at the best price. After researching several articles, and looking up several places to buy, I finally landed on a pair of Rebook training shoes, which I ordered from Amazon as they had the lowest price.

Shoes wear out; the next time I need to replace these shoes, I’m sure I’ll do the same thing, going through the same process.

There’s a hundred other examples of this process when I look for something I want/need, and I’m sure you have them to.

Where I do NOT go through this process, as a personal example, is with my car. I go to my friend, whom I trust with any issue that may arise.

There’s a lot of things that could need attention in my car, of which I could go look up online and compare features, price, etc., as well as mechanics and shops that could provide these services that are needed. But I don’t want that, I don’t care if I could get something a little cheaper, or quicker. I just want my car back up and running as smoothly as possible, and I trust John to do that.

See in this scenario, for me,
I’m not needing to spend time researching prices,
I’m not bouncing back and forth comparing features,
I’m not worried about other’s reviews,
I won’t ever need to call an 800 call center number for help and be put on hold if I have a question,
And I won’t have to go through this whole process again the next time my car needs attention.

I just pick up the phone and call John. I drop it off. It gets fixed. I pick it up. I’m good to go.

Hopefully everyone reading this article has someone like this in their lives. Whether it be your mechanic, lawyer, financial adviser, or whomever, we have people we trust and go to every time. We don’t shop around, we don’t call 1-800 call centers, and for the most part we avoid the headaches and stress we would have otherwise.

That’s what we want you to feel when you work with Madden. Chemical metering pumps aren’t exactly fun and glamourous, but they are a pivotal part in many industrial, commercial, and municipal operations. When you need to buy one, need one serviced, or just have general questions, we want you to be confident in the fact that not only would our pump provide great longevity in the first place, but that you’ll always be comfortable, confident, and trusting when calling our shop.

Less headaches, less stress.


If you have a chemical metering application that calls for constant dosing throughout the day, week, and year, consider joining the Madden family for the foreseeable future.
We may be small but we have over 65 years of experience and a great team of pump equipment distributors representing us across the country. Whether dealing with our team of sales reps, or directly with us, you’ll quickly notice the expertise, personability, and responsive service right away.

And on top of that, our chemical pumps just flat out last a long time. You won’t be calling us often.

Thank you for spending the time reading our article, and if we’ve convinced you that we’re worth a shot, please give us or one of our distributors near you a call and let us know what your application is. We’d love to help design your next chemical metering pump and potentially a full system.