Diaphragm Type Metering Pumps

This blog is intended to break down all of the options you have when considering a Madden Metering pump. It will do so by going through a simple and brief walk through on how to select the right pump for an application. Each step will contain an explanation, then look to the bottom of the blog for our material guide “cheat sheet” to help put it all together.

Step 1: Let’s start with your desired flow rate

Madden can provide a pump to go as low as 0.1 GPH (0.38 L/hr) and as high as 360 GPH (1,362 L/hr). From our literature, you may think that Madden’s minimum output is 1 GPH, but keep in mind that Madden pumps have a 10:1 adjustment knobs which allows for manual adjustment of the stroke length of a pump. You may also think the max is 180 GPH, but we can duplex the pumping heads to double the output. Let’s take a closer look.

Madden offers 3 different model series of pumps which service various flow rates in between 1-360 GPH and they are:

  • The JN Series: 6 models with maximum outputs ranging from 1-11 GPH *Simplex. Duplex and Triplex also available.
  • The MF Series: 11 models with maximum outputs ranging from 5-75 GPH, *Simplex. Duplex and Multiplex also available.
  • The MH Series: 5 models with maximum outputs ranging from 96-180 GPH, *Simplex. Duplex also available.

*Simplex, Duplex, Triplex, and Multiplex refer to how many wetted ends or pumping heads these models can have. We can put up to four pumping heads on an MF series pump for example, effectively quadrupling the output if one were to be pumping the same liquid via all four heads.

Step 2: Now let’s see what material options you have for the wetted end

Keep in mind, you can always call or email us the name of the liquid to be pumped and we will design the best wetted end for pumping that liquid. Madden has wetted end materials to handle nearly all corrosive liquids, acids and caustics alike.

*Scroll down to see our “cheat sheet”. The bottom of this document shows all of the materials available for each Madden Pump Model Series. (Page 4 on the brochure)

Step 3: Do you need something other than a standard motor?

At Madden we stock standard 1725 rpm, 56 frame, TEFC, 1/60/115-230 or 3/60/230-460 motors. Because of this, we can usually have a pump out within a couple of days in emergency cases.
But we don’t limit you to these choices. Check out all of the other motor types we provide:
1.    Explosion Proof
2.    Washdown Duty
3.    Mill & Chemical Plant Duty
4.    Inverter Duty
5.    50 Hz

Step 4: And finally, what about other Accessories

We offer many accessory components for convenience and further performance for our customers. The next two are some of our more prominent accessories.

Variable Speed/Frequency Drives, Automatic Control: Madden is capable of providing an inverter duty motor with a VFD for automatic pump applications. Both AC and DC variable speed drives are available to suit nearly every application using a 4-20mA signal for pump output control.

DDB double diaphragmWhen pumping highly corrosive liquids we strongly recommend this DDB setup. What we do is add a secondary, back up diaphragm to ensure the corrosive liquid will never come in contact with the pump’s interior components. There is a secondary piston and a spacer in between the primary and secondary diaphragms. This spacer allows for leak detection. All in all, this option helps ensure you will only ever need minor repairs or replacements, our pumps are made to last 24/7/365!

What else? Check out the remaining accessories available for your next Madden Pump:

  • Back Pressure Check Valves: required when outlet connections pressure is less than 20 psi to enable pump valves to operate properly for accurate pumping. Sizes range from ¼” to 2”, adjustable Teflon diaphragm with body material to match the pump construction.
  • Relief Valves: Required when outlet line may become closed to prevent over pressure on piping and pump components. Sizes from ¼” to 2”, adjustable, Teflon diaphragm with body material to match the pump construction.
  • Pulsation Dampener: Eliminates pulsing flow and pressure peaking characteristics of piston type pumps. Available in sizes and material to match pump construction.
  • Calibration Cylinder: Seven sizes from 100 mL to 20,000 mL, clear PVC material, used to calibrate pump output at various adjustment knob settings.
  • Leak Detector Switch (pressure type): Type 316 SS, used with type DDB double diaphragm to signal a leak in the primary diaphragm for prevention of damage from corrosive or dangerous liquids.
  • Pump Mounting Base: Heavy steel construction. Available for MF and JN series.
  • Pump Cover: Protects MF and JN series pumps from weather, galvanized steel.

Cheat Sheet

To make it as easy as possible, take a look at page 4 of our Diaphragm Metering Pump Brochure. This link will take you there. Page 4 is what we affectionately call our cheat sheet.

Metering Pump Brochure ♦


We specialize in one type of pump. Our mechanically actuated, industrial duty chemical metering pumps are of the highest quality and come with plenty of options to insure consistent and accurate pumping of critical liquids 24/7/365. So if you’re in need of a chemical metering pump, Madden has you covered.