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Dosing Pumps

Dosing Pumps for Chemical Injection

When you need a tough, dependable pump for chemical dosing Madden has a pump for you. Madden diaphragm type dosing pumps are designed for mills, mines and water treatment facilities where chemicals must be pumped all day long, year round. Engineered materials are used for the wetted end to pump virtually any chemical, from acids to caustics. Even viscous liquids and suspended solids can be metered and pumped with precise accuracy.
JN10-A Pump

  • JN Series: Dosing Pumps
  • 6 models from 1 to 11 GPH (4-42 L/hr)
  • Simplex, duplex and triplex metering pumps available
MF Series Pump
  • MF Series: Dosing Pumps
  • 11 models from 5 to 75 GPH (19-340 L/hr)
  • simplex, duplex, triplex and quadruplex metering pumps available.
MH Series Pump

  • MH Series: Dosing Pumps
  • 5 models from 96 to 360 GPH (363-1,362 L/hr)
  • Simplex and duplex metering pumps available.

Madden diaphragm metering pumps are designed for tough industrial uses.


Precision is important in chemical metering applications to make sure you get just the right amount of chemical added to the process. Repeatable accuracy of +/- 1% over a 10:1 turndown ratio is maintained with the stroke adjustment control located conveniently on the top of the Madden pump.


The Madden pump’s mechanically actuated diaphragm design makes irritating hydraulic systems and packing glands obsolete. Large bearings and shafts, continuously lubricated with a bath of oil, give many years of dependable service. Precision bronze worm gears and steel worm drive shafts generate piston pumping power. The heavy duty diaphragm keeps the chemical from penetrating the inner gear works. Replacing worn wetted end parts is quick and easy, and accomplished with common tools.

Chemical dosing pumps by Madden are heavy duty industrial grade, using standard industrial 56 frame motors and worm gear reducers to produce reliable chemical pumping power designed to provide years of dependable service. Features include: 
  • Mechanically acuated pump design
    Mechanically acuated pump design
    Heavy duty gearing and tapered roller bearings
  • OSHA designed coupling guard
  • Wetted end parts made from a selection of corrosion resistant materials including Teflon, 316 stainless steel, polypropylene and PVC
  • Thick Nylon reinforced diaphragms for years of tough pumping service. Materials include Teflon faced, Viton, Hypalon and Neoprene
  • Industrial grade 56 frame electrical motors are available in 50 Hz and 60 Hz power, with a variety of enclosures to meet the site requirements
At Madden we design our pumps with your chemical dosing system in mind.

Why use a Madden pump for chemical dosing?

Adding too much of the chemical with uncontrolled pumping will waste money and it could also reduce the process quality. A Madden dosing pump is designed to enable the operator to control the rate of chemical addition to make sure the results are within the limits of the specifications for the process.

Safety Features

Type DDB Double Diaphragm

Often times when dosing applications arise, the liquid needing to be metered is a corrosive and dangerous chemical. These chemicals are not only harmful to human skin, but they can be extremely corrosive to metals, rubbers, and other materials found in the plant. When dealing with corrosive chemicals like this, parts fatiguing on the pump is inevitable. And a potential leak or rupture in the pumping system can have dangerous and costly consequences. Madden's Type DDB Double Diaphragm construction is a feature meant to minimize/eliminate the dangers and potential losses that result from a rupture or leak in the system. This is achieved by adding safety features to the pump to ensure the operator that the corrosive liquid will not enter the interior of the pump or leak on the shop floor. And it's dry mechanical design means never having to worry about hydraulic barrier fluids
JN series single primary diaphragm construction JN series type DDB double diaphragm construction
Standard, single diaphragm design Type DDB double diaphragm design
 entering the application in the case of pharmaceutical and food applications.

Construction: The DDB double diaphragm construction design adds a spacer and another, backup/secondary diaphragm to the chemical pump’s wetted end to ensure the corrosive chemical, like caustic soda, never reaches inside and damages the pump’s interior components. This is one big reason why, when properly maintained, there are Madden dosing pumps out there that have lasted for over 25 years with only minor wetted end parts needing to be replaced.

The picture above is of a Madden JN series pump with a standard, single primary diaphragm design, and a Madden JN series type DDB double diaphragm design.

Leak Detecting Pressure Switch

1/4 inch Leak detecting pressure switch
Another great feature that comes with the type DDB double diaphragm is the ability to place a pressure switch in the spacer between diaphragms. There is a 1/4” NPT hole in the spacer that allows for a pressure switch to be installed. The pressure switch should be set to the lowest level. Under normal operating conditions the pressure inside this spacer is the same as the ambient air surrounding it. So if the pressure switch is set to its lowest setting and there is any kind of rupture in the pump’s diaphragm, the smallest amount of pressure that results will set off the pressure switch. From there you can either wire it to an alarm or wire it to shut of the motor; making absolutely certain harsh chemicals like sodium hydroxide will never touch the shop floor or anything else near the pump.

Madden Metering Pump Selection Guide

For the cleanest and easiest way to inquire about a Madden metering pump, download this fillable pump selection guide, fill it out, and upload it through the RFQ section of our website. We take pride in responding promptly!
Metering Pump Selection Guide

Dosing Pumps – for chemical injection - Made to Order

Madden Manufacturing doesn’t just manufacture dosing pumps. We can also build entire pumping systems. 
Made to order Chemical Metering Pumps Made to order Chemical Metering Pumps
Example 1 of a made to order system Examples 2 of a made to order system

Click here to contact us to let us know what your requirements are and we'll see what we can do!
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Automate Your Application

With the help of local experts at JK Industrial Controls, Madden now has the ability to completely automate your pumping applications. Take a look at our Automation and Controls webpage or fill out the contact form below to learn more!

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