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Chemical Pumps

Chemical Pumps - Three Pump Series

Madden chemical pumps are designed for demanding industrial jobs where chemicals must be pumped all day, every day. 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 pumped with volume controlled accuracy.
JN10-A Chemical Pump

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


Extremely Accurate

Repetitive accuracy of +/- 1% over a 10:1 turndown ratio is achieved with a convenient stroke adjustment knob located on the top of the pump.

Durable, Low Upkeep

The mechanically actuated diaphragm system eliminates annoying hydraulic systems and packing glands used in many chemical pumps. Large bearings and shafts, continuously lubricated with a bath of oil give years of dependable service. Precision bronze worm gears and steel worm drive shafts convert motor rpms to linear piston pumping power. Replacing worn parts is fast and simple, and can be done 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 pumping power designed to provide many years of dependable service. Rugged aluminum gear box and pump body castings, precision machined and bolted assembly. Wetted end parts made from a selection of corrosion resistant materials. Thick Nylon reinforced diaphragms for tough pumping service. Industrial grade 56 frame electrical motors are available to meet any enclosure and power supply need.

How does a Madden chemical pump work?

The Madden diaphragm type chemical dosing pumps are positive displacement chemical pumps that allow the operator to adjust the displacement of the pump which changes the output rate. Madden pumps are “lost motion” type pumps which use a piston to mechanically move a rubber diaphragm that is the barrier separating the liquid from the inner workings of the pump. An electric motor drives a worm gear speed reducer that in turn turns a shaft with an eccentric installed on the shaft. As the eccentric moves forward the piston is pushed forward, along with the diaphragm, and the liquid that is in the wetted end of the pump is pushed out through the discharge check valve and into the piping going to the industrial process. As the eccentric continues to rotate through a 360-degree cycle it will eventually push the piston rod rearward, which pulls the diaphragm rearward. That rearward action creates a vacuum in the wetted end of the pump resulting in the chemical liquid being sucked into the wetted end through the suction side check valve.

To see one in action, click here, or watch the video below.

Safety Features

Type DDB Double Diaphragm

When chemical pump metering applications arise, the liquid needing to be metered may be 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 are 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 pump system. This is achieved by adding safety features to the chemical pump to ensure the operator that the corrosive liquid will not enter the interior of the pump or leak on the shop floor. The dry mechanical design means never having to worry about hydraulic barrier fluids
JN series chemical pump single primary diaphragm construction JN series chemical pump 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.

DDB double diaphragm construction

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

The pictures to the right show a Madden JN series pump with a standard, single primary diaphragm design, and a Madden JN series type DDB double diaphragm design.

DDB Double Diaphragm leak detecting pressure switch

Type DDB chemical pump pressure switch location Chemical pump leak detecting pressure switch
Another great feature that comes with the type DDB double diaphragm is the ability to place a leak detecting pressure switch in the spacer between diaphragms. There is a 1/4” NPT hole in the spacer that allows for the pressure switch to be installed. The switch should be set to activate at its lowest pressure setting. Under normal operating conditions the pressure inside the spacer is the same as the ambient air surrounding it. If the pressure switch is set to its lowest setting and there is any kind of rupture in the pump’s primary diaphragm, the smallest amount of pressure that results will activate the pressure switch. From there you can either wire it to an alarm or wire it to shut off the motor if a leak it detected; making absolutely certain harsh chemicals such as 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 in the RFQ section of our website. We take pride in responding promptly!
Metering Pump Selection Guide

Chemical Pumps - Three Pump Series - Made to Order

Madden metering pump feed system

Madden Manufacturing doesn’t just manufacture chemical pumps. We can also build entire pumping systems.

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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Faster Lead Times than Neptune & Milton Roy

Madden Manufacturing is currently quoting lead times of:
  • Chemical Metering Pumps @ 1-2 weeks
  • Fully Assembled Chemical Feed Systems @ 3-6 weeks
  • Sample Coolers & Small Heat Exchangers @ < 1 week
  • Emergency/Rush pumps in 1-2 days!

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