Overview

Mechanically actuated metering pumps are driven by a motor, worm gears, drive shaft, eccentric and piston. The motor speed is first slowed or reduced to a desired stroking speed using worm gears. These worm gears are what will then turn the drive shaft at a desired speed. The drive shaft will turn an eccentric which is a type of cam; this ultimately provides the stroking motion of the piston. Madden pumps have a molded rubber diaphragm with a screw on the back side of it that is directly fastened to the piston. The forward and reward stroke of the piston directly actuates the primary diaphragm. When the piston is pulled rearward it pulls the diaphragm rearward and that creates a vacuum that sucks liquid into the pump. As the piston and diaphragm move forward, liquid is pushed out of the pump.

(*Term: primary diaphragm- the diaphragm that comes into direct contact with the liquid being pumped.)

Hydraulically actuated diaphragm metering pumps have the same starting components, meaning they also use a motor, worm gears, and a drive shaft/eccentric/piston of some sort to accomplish the reciprocating motion. However, the piston (usually a plunger) does not come in direct contact with the primary diaphragm. Between the piston and the diaphragm is hydraulic fluid. The reciprocating motion of the piston pressurizes the hydraulic oil which pushes on the diaphragm.

Both mechanically actuated and hydraulically actuated metering pumps are well suited to pump dangerous and corrosive chemicals. Hydraulic pumps have the potential to incur expensive consequences when a leak occurs. This is due to the barrier fluid used to actuate a hydraulic pump’s primary diaphragm. If the barrier fluid enters the process, it could have dire effects on a product.

Madden type DDB double diaphragm metering pump vs Hydraulic double diaphragm metering pump

When pumping dangerous or corrosive chemicals, metering pump manufacturers will suggest adding a secondary/backup diaphragm. Madden does this with their type DDB double diaphragm construction, which is comparable to a double diaphragm hydraulically actuated metering pump.

The main difference? With the type DDB double diaphragm “hardware” is used to connect the piston to the primary diaphragm, rather than a barrier oil. As you can imagine, when hydraulic pumps add another diaphragm, they add another cavity, or barrier, and fill this with another oil (a.k.a. barrier fluid) to actuate it. Likewise, when mechanically actuated pumps add a secondary diaphragm, they need a secondary piston to be placed between the two diaphragms.

Example of MF series type DDB double diaphragm construction

So what is the advantage of a mechanically actuated pump over a hydraulically actuated pump?  We believe the pivotal advantage stems from the fact that diaphragm fatigue/rupture is unavoidable; and on a hydraulically actuated pump it could cause thousands of dollars in damage or wasted products when hydraulic oil or a barrier fluid is pumped into the application.

Mechanically actuated advantage: these pumps cannot ruin a product due to barrier fluid contaminating the process. The Madden type DDB double diaphragm construction, as an example, contains no fluids in the spacer between the double diaphragm construction, only a secondary piston. This means no fluids can be pumped into the product.

Hydraulically actuated liability: ruptures in the primary diaphragm could cause the hydraulic pump to pump barrier fluid into the product, thus ruining an entire batch of product.

Point being, diaphragms will inevitably fatigue and rupture. There are precautions you take to avoid unnecessary damage (which we’ll talk about later in this blog) including leak detectors and regular maintenance, but nothing can beat the assurance of a dry chamber when it comes to pumping sensitive liquids like pharmaceuticals and food grade liquids.

Here’s a quick story to help understand how this peace of mind could have been achieved…

Example: we recently were involved in an inquiry for a large pharmaceutical company who had a costly malfunction. One of their many hydraulically actuated diaphragm metering pumps had a diaphragm reach fatigue; the problem for them was the double disc system used a barrier fluid acting as the hydraulic actuator for the primary diaphragm.

When the primary diaphragm failed, the barrier fluid entered the pharmaceutical product being pumped and ruined the entire batch.

Mechanically actuated diaphragm pumps do not have any fluid between the secondary diaphragm and the primary diaphragm. In this case, it was suggested they look at the Madden diaphragm metering pump line. Had this large pharmaceutical company been using a Madden pump with a type DDB double diaphragm construction, their worst-case scenario would have been a minor loss in volume of product, not an entire batch being contaminated.

Think of a mechanically actuated metering pump’s construction as the final precaution that will answer every “what if” and “you never know”.

“What if” we somehow overlook replacing the diaphragm just the one time, or “what if” someone accidently forgets to plug in the leak detector switch, and we ruin an entire batch of product… “you never know”.

With Madden mechanically actuated metering pump and a type DDB double diaphragm, you know your answer is only a minor loss in product by volume equivalent to the time the pumps ran with a ruptured diaphragm. And one last advantage, repairing hydraulic pumps can be messy and complicated, Madden wetted end repairs can be done in 10 minutes with an adjustable wrench.

Added Safety Feature Available with the Madden type DDB double diaphragm construction:   Leak Detecting Pressure Switch

As discussed earlier, Madden metering pumps equipped with a DDB double diaphragm have a secondary back up diaphragm, a spacer, secondary piston, and primary diaphragm. The secondary diaphragm is there to make sure the liquid being pumped never comes in contact with interior components of the pump, which means only minor wetted end repair will ever be necessary

The other feature that this section in the blog is referring to is the weep hole in the spacer. The weep hole allows for a visual aid showing when the pump’s primary diaphragm has a leak. It has a 1/4” NPT connection where a leak detecting pressure switch can be installed. The pressure inside the spacer (between the secondary and primary diaphragms) will be the same as the ambient air surrounding the pump. With the leak detecting pressure switch set to its lowest setting, if any pressure at all builds inside the spacer, it will be due to a leak, and the leak detecting pressure switch will then immediately activate. You can wire the leak detecting pressure switch to either sound an alarm or directly turn off the pump.

A Madden diaphragm metering pump with a type DDB double diaphragm and leak detecting pressure switch will be plenty to give you peace of mind that your application will never leak or spray dangerous chemicals around the shop floor or surroundings; and if that isn’t enough, remember you can always fall back on the mechanics of a mechanically actuated pump, it will never waste a batch.

Conclusion

If you’re pumping a dangerous liquid or a liquid that must not be contaminated in any way, consider a Madden mechanically actuated diaphragm metering pump. They are extremely accurate, consistent, and durable. Our metering pumps are made of aluminum bodies and heavy-duty construction for the interior components, and everything is made and assembled in the U.S.A.

The post Mechanically VS Hydraulically Actuated Diaphragm Metering Pumps appeared first on Madden Pump.

Precise:

The closeness of two or more measurements to each other. Precision is how often you can repeat the same measurement, regardless of the targeted value.

VS.

Accurate:

The closeness of a measured value to a standard or targeted value. Accuracy is the ability to closely hit a targeted value.

Pressure, temperature, and viscosity affect a metering pump’s flow rate. For example, at an operating pressure of 50 psi let’s say a metering pump is metering 5 gallons of a chemical in an hour. If this same application had to operate at a pressure of 150 psi, the flow rate will drop slightly to something like 4.5 gallons of chemical in an hour. A small amount, but with applications that call for extreme accuracy, not knowing you lost 0.5 gallons in an hour can make all the difference in the world.

This article is focused on helping the pump operator to reach their exact desired output. Once achieved, a quality metering pump, like Madden diaphragm metering pump line, will repeat that targeted output, with an accuracy of +/- 1% for years of dependable service life.

So why the need for such precision and accuracy? Many other pumps have controllable outputs.

There are several reasons why one would need a liquid/chemical pumped with precision and accuracy of +/- 1% via a metering pump, rather than settling for a centrifugal pump with controls for the output (as an alternative example).

1. Errors in production: You will want repeatable +/- 1% accuracy when the application calls for the dosing of a liquid/chemical to produce a different liquid or chemical. If a pump outputs too much or too little, the resulting solution will not serve its purpose.
2. Wasting money on your product: In this scenario adding too much of a liquid or chemical to a process may not harm the resulting solution, but it is a waste of the liquid/chemical, nonetheless. And if your pump is running 24/7/365, pumping too much of a liquid/chemical will hurt your bottom line. Wasting chemicals is expensive and can be harmful to the environment.
3. Wasting money via your time: If you are trying to design a centrifugal pump to act as a dosing pump, it will take a lot of time for an engineer to come up with the right instrumentation to do the job. You will either need to spend thousands of dollars to automate the system, or an operator will need to constantly monitor and adjust the pump. With a metering pump, once you have it running at the flow rate you need, you can walk away and be confident it will dose the specific amount needed.

Understanding Madden metering pumps, and how to ensure +/- 1% accuracy

Madden has 3 different series of diaphragm metering pumps, the JN series, MF series, and MH series. Among our 3 series of pumps are many different models with different minimum and maximum output capacities. Let’s walk through an example of how and why you need to calibrate a Madden metering pump to achieve and exact output with +/- 1% accuracy.

For this example, let’s use a Madden MF160C which has a flow rate range of 6-60 GPH and is rated for up to 160 psi operations. Let’s understand what all can cause the actual rate for this Madden MF160C to vary by a max of a few gallons per hour. These factors include:

• The system’s back pressure being well above or below 100 psi (every Madden pump is tested at 100 psi before they leave the shop to ensure it reaches the model’s rated output and has no leaks or other defects)
• The pump is or is not set up with a flooded suction. And vice versa, any suction lift the pump must overcome will affect total output.
• The system’s total feet of piping to the point of metering is extensive
• There are many turns in the piping, causing more drag/friction
• Pipe size is significantly bigger or smaller than the pump’s inlet and outlet sizes
• Temperature
• Viscosity

As you can see, there are many factors that play a part in the actual output of a metering pump. Remember all these factors are only going to affect the pump’s output by a few gallons per hour at the most.

The purpose of all this information is to help end users understand the need to calibrate your metering pump to know exactly what you’re getting in output. Sticking with our MF160C example, let’s say you wanted to pump at 30 GPH. It isn’t as simple as turning down the manual adjustment knob to 50%. Turning the manual adjustment knob down to 50% on a MF160C may get you 29.1 GPH or 29.5 GPH, it is dependent on pumping conditions. If you need 30.0 GPH exactly, then it’s time to calibrate.

So how do you ensure your Madden pump is pumping exactly what you need to pump?

The two easiest and best ways to ensure your Madden pump is giving you an accurate and precise output is to calibrate it using either calibration columns or a flow meter with a rate and totalizer.

And Madden has you covered on both.

Madden standard line of Griffco PVC calibration columns can handle any flow rate of a Madden metering pump. The units are listed below

Calibration Columns

Using a Griffco calibration column is easy and extremely accurate. You will need to purchase two isolating valves to be used at the top and bottom ends of the calibration column. The top of the cylinder should be vented back to the storage tank or to drain. To begin, fill the cylinder to the top mark then close the valve from the chemical tank. Switch on your Madden metering pump and draw down the chemical in the cylinder for 60 seconds. Switch the pump off.  Use the number of mL or CC’s that has been pumped out of the cylinder to find your Madden pump’s current flow rate by dividing by 3,785 and then multiplying that number by 60. Here’s a couple of examples on the uses of a calibration column (continuing with an MF160C):

Example 1, fine tuning for exact output: Here we have filled a Griffco calibration column to the top and our Madden MF160C’s manual stroke adjustment knob turned to 100% which is “100” on the dial scale. We then turn on and pump for 1 minute after which we note that 3,887 mL have emptied from the calibration column. If we divide 3,887 by 3,785 we get 1.027, and this multiplied by 60 brings us to 61.62 gallons per hour. So in this example our Madden MF160C is pumping 1.62 gallons more than its rated max capacity (likely due to low operating pressures).

The next step would be to back off the manual stroke length adjustment knob slightly and repeat the processes until you are at exactly 60 GPH, if this is the output you desire.

Example 2, performing multiple runs to develop your pump’s curve: in this scenario we start the same way as we did in example 1. After we have recorded our rate when the manual stroke length adjustment knob of our pump was at 100%, which again, is “100” on the dial scale, we should run the test at least 3 more times. Madden Pump suggests using “75” on the dial scale, “50” on the dial scale, and then “25” on the dial scale for the next 3 runs.

Using these 4 recorded outputs will allow you to draw an output curve for your pump in its current application. This will allow you to know how much your Madden metering pump will pump at nearly any number on the manual stroke length adjustment knob dial without having to use the calibration column every time you make an adjustment.

Flow Meters

Madden also offers Seametrics flow meters for end users. There are a wide variety of flow meters to meet nearly any flow rate and chemical resistance need. Contact the factory for options and pricing.

If you don’t see something you like here, contact us to find out what more we can offer. If you have an inquiry about any products that compliment a Madden Diaphragm metering pump, we will look into procuring that for you.

Conclusion

If you have an application that needs precise and accurate metering, consider a Madden Diaphragm Metering pump. Consistency and durability are the focus of our chemical metering pumps and we have the instruments to make your pumping capacities exactly what you need them to be.

The post Adjusting the Flow Rate/ Output of a Madden Pump appeared first on Madden Pump.

Madden metering pumps are made to order. When ordering a pump, we will need to know:

1. Your desired output/ flow rate
2. What chemical you’re metering
3. What type of motor you need
4. If you are looking for any other accessories for your system

With this information, our engineers can design a pump to best suit your needs as opposed to selling you something out of a catalog. Let’s take a closer look at the options.

Step 1: 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 knob 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 series of pumps which service various flow rates in between 1-360 GPH. There are numerous models in each series.

• 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. Click here to read our previous article about duplex, triplex, and multiplex pumps.

Step 2: Wetted End Materials

Madden has wetted end materials to handle nearly all corrosive liquids, acids and caustics. The options depend on the model of pump that you select; they include 316 Stainless-Steel, PVC, Teflon, Polypropylene, Neoprene, Hypalon, Viton, Ceramic, Hastelloy C, and Alloy 20.

The table pictured below shows which materials are available for which pumps.

Step 3: 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: 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 can provide 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 diaphragm: When 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.

Call Or Email Today

Our mechanically actuated, industrial duty chemical metering pumps are of the highest quality and come with plenty of options to insure consistent and accurate metering. If you’re in need of a chemical metering pump, Madden has you covered. Give us a call 1-800-369-6233 or send us an email sales@maddenpump.com to discuss your next project.

The post Madden Chemical Metering Pumps: Made to Order – Customized for your Business appeared first on Madden Pump.

Among Madden’s many customizable features, customers can duplex (double), triplex (triple), or multiplex (quadruple) the pumping heads.

A quick explanation:
In the pumping world, this means a mini pumping system built into the pump itself. One motor, one worm gear reducer, and one drive shaft drive 2-4 pumping heads. You can design each pumping head with different materials to handle different liquids. You can also manually adjust each head’s stroke length over a 10:1 turndown ratio.

Capabilities per Series

• JN series metering pumps – up to 4 pumping heads
• MF series metering pumps – up to 4 pumping heads
• MH series metering pumps – up to 2 pumping heads

Possible Applications

If budget restrictions make buying 2, 3, or 4 separate pumps impractical, consider a Madden multiplexed pump instead. This works well when the flow rates of the liquids you’re pumping are close to each other. A multiplex pump also saves floor and shelf space compared to buying multiple pumps.

Here’s a quick list of what you can do with a Madden pump that has multiple pumping heads:

1. Simply double, triple, or quadruple capacity/output.
2. Pump 2, 3, or 4 different liquids at the same time.
3. Send each liquid to a different destination.
4. Adjust each individual pumping head to a different output/capacity.

Example: Take an MF218C Madden duplex metering pump, which delivers up to 18 GPH per pumping head. Say you need to pump two liquids (“A” and “B”) into the same system. To create the right concentration for the resulting liquid “C,” you need “A” at 18 GPH and “B” at 9 GPH.

Instead of buying two separate pumps, you could choose a Madden MF218C duplex metering pump. It handles both liquids using two wetted ends built with materials suited to “A” and “B.” You simply turn one pumping head’s stroke adjustment knob down to 50%. Easy as that!

Function, How it Works

This video goes over how our Madden MH duplex pump works –

The post Duplex, Triplex, and Multiplex Diaphragm Metering Pumps appeared first on Madden Pump.

When you are selecting a pump for your metering system, it is very important that the wet end of the pump is made of materials that are resistant to the chemical you are pumping. There is a lot of documentation online about chemical resistance. This is a great place to start. Madden Pump has been designing and manufacturing pumps since the 1950s. Our experience will help you bridge the gap between the information you find online and the practical reality of pumping chemicals.

Sodium Hypochlorite

Sodium Hypochlorite varies in level of concentration. Identifying the level of concentration will help determine the most cost-effective way to meter sodium hypochlorite.

For example, most of our customers who pump sodium hypochlorite use a mixture that is 10-15% concentrated. Based on this mixture, we would recommend the following materials for the wet end of your pump:

Solution Head: PVC
Diaphragms: Viton
Valve Seats: Viton
Valve Check Balls: Teflon

When pumping a harsh chemical like sodium hypochlorite we always recommend our double diaphragm design. This design provides extra protection. If your chemical mixture eats through the first diaphragm, or the diaphragm simply wears out after years of pumping 24/7, the second diaphragm will block the mixture from getting into the dry side of the pump. It is much less expensive to purchase and install a new diaphragm than it is to fix the dry side of a pump that has been exposed to harsh chemicals.

Conclusion

Our material recommendations are based on the chemical you are pumping and the concentration. If you are pumping sodium hypochlorite and the concentration exceeds this level, we may make a different recommendation. Call or email us today to discuss the specifics of your project so we can make a recommendation. Alternatively, we have reps across the country that we can recommend should you want a local contact point. We pride ourselves on providing great customer service. We will work with you to find the best pump that will last as long as possible to keep your process running smoothly 24/7/365.

Website: maddenpump.com
Email: sales@maddenpump.com
Phone: (574) 295-4292

The post Metering Pumps for Sodium Hypochlorite appeared first on Madden Pump.

Madden has been in the business of designing and building pumps for over 70 years. We have seen the landscape change as more and more manufacturers move to using cheaper materials and designs that limit lifespan. While other manufacturers have shifted their business models to boost profits and build in obsolescence, Madden’s business model has not changed. When we first started designing and building pumps, our goal was to create the most cost-effective diaphragm metering pumps on the market. We remain dedicated to this goal 70 years later.

What Makes Madden Pumps the most cost effective long term?

The are numerous factors to consider when you are choosing the right pump for your project. When looking at upfront costs, it may be tempting to test your luck importing an inexpensive pump. This is a shortsighted decision that some of our customers have made in the past and later regretted. When choosing the right pump for your application you must consider:

– What is the expected lifespan?
– Is the pump repairable and does the manufacture sell parts?
– How long will repairs/replacement take should you run into an issue?
– What is the opportunity cost of downtime?
– Is the manufacture accessible should you run into an issue?

What is the expected lifespan?

Regardless of what pump you purchase, corrosive chemicals will deteriorate the wet end of your pump. This is the most common point of failure. Madden has many customers who have had our pumps in service for 25 years only doing wet end repairs. We offer a double-diaphragm design that protects the dry end of the pump should the main diaphragm fail. Many the pumps sold today are not meant to be repaired. If one part fails, you are forced to replace the entire pump.

Is the pump repairable and does the manufacturer sell parts?

Over the past 40 years we have seen manufacturers across many different industries move towards planned obsolescence. Pumps are no different. Manufacturers are using cheaper materials and designing products to be replaced rather than repaired. The continuous design changes make it so that, even if the company sells replacement parts, they often stop manufacturing parts for older models.

Madden sells replacement parts for all of our pumps. Our designs are field tested and proven to be reliable. Any design changes we have made over the last 70 years have been to increase durability and dependability. While we have made some design upgrades over the years, our parts are always backwards compatible. If you own a Madden pump, you will never run into an issue with getting replacement parts.

How long will repairs/replacement take should you run into an issue?

Madden pumps are designed to make repairs quick and easy. The parts that may eventually need replacement are easily accessible without removing the pump and installation can be done by anyone with basic hand tools. These qualities minimize downtime and eliminate the need to bring in an outside technician.

What is the opportunity cost of downtime?

Pumps are critical to most of our customer’s operations. When choosing a pump manufacturer, you need to think ahead to what your experience will be like when the pump stops working. Can you afford to be without a pump for days or weeks?

Our customers often keep spare parts on hand so that, should something fail, they can have the pump back up and running within hours. If you need a part and don’t have a spare on hand, we will get one to you quickly. If you are unsure what is wrong with your Madden pump, we are here Monday-Friday to talk through the problem and identify what you need.

Is the manufacture accessible should you run into an issue?

At Madden we take pride in customer service. Our team is available by phone 1-800-369-6233 or email sales@maddenpump.com. We will quickly get any issue you run into resolved. If you call early in the day (Monday-Friday), we can often ship replacement parts out the same day. We are also here to guide you through the process of replacing parts.

The post Cost Effective Chemical Metering Pumps appeared first on Madden Pump.

We design and manufacture Custom Chemical Feed SystemS

Today we are testing one of JN Series pumps that will be installed in a custom chemical feed system. This system will include a tank, high-speed mixer, variable frequency drive, and pump, all mounted on a platform with suction and relief piping.

Our chemical feed systems are made to order and our pumps come in many different configurations. The pump on test today is designed to pump 0.4 – 4.0 gallons per hour. It has a stainless-steel solution head, Teflon-faced diaphragm, Teflon valve seat, stainless-steel valve balls, and a ½ horsepower motor. When designing a chemical feed system, we will guide you through the process of selecting the right materials and the proper configuration for the chemicals you are metering.

The post Custom Chemical Feed Systems appeared first on Madden Pump.

Diaphragm metering pumps are relatively simple in design. Madden pumps generally consist of four main sections: the wetted end, the drive system, the motor, and the output adjustment. Madden builds pumps with rugged materials that stand the test of time. When a part wears out after years of use, the simple yet affective, design of our pumps makes for easy maintenance. Both of these factors contribute to our overall goal of building high-quality pumps that will meter chemicals accurately with little-to-no downtime. Our pumps are designed to meter chemicals within +/- 1% of your desired flow rate.

The diagram below shows the four basic sections of our JN and MF Series pumps. We will take a more in-depth look at these sections below.

Wetted End

The wetted end refers to the section of the pump that comes in contact with the liquid that will be pumped. This section consists of several parts: the solution head, the diaphragm, the inlet and outlet check valves and the piping connectors.  All of these components need to be compatible with and resistant to the chemical that will be pumped.  Madden and other metering pump manufacturers like LMI, Milton-Roy and Pulsafeeder offer a wide range of materials for the wetted end construction to allow the pump specifier to select the right materials for each pumping application. Piston or plunger type metering pumps do not use a diaphragm to separate the liquid in the wetted end from the drive mechanism.  Those pumps use a packing gland for the purpose of containing the liquid.

Drive System

The drive system section takes the rotary power of an electric motor and converts it into a piston stroking action.  Madden and many other metering pump manufacturers use a right-angle worm gear reducer to convert the 1725 rpm electric motor speed to a stroking speed ranging from 15 to 230 strokes per minute in different pump models.  The gear ratio used in the worm gear reducer will determine the stroke speed; i.e. a 10:1 gear ratio will reduce the 1725 rpm motor speed to 172 strokes per minute drive shaft speed.  The connecting rod and piston are driven by the drive shaft.  As the drive shaft rotates, the connecting rod and the attached piston, will make a stroke in and out, driving the diaphragm in the wetted end which moves the liquid being pumped.  Madden uses heavy duty industrial grade worm gear reducers to insure many years of trouble-free pumping service. Madden pumps have a mechanically actuated diaphragm, so the piston is directly connected to the diaphragm in the wetted end.  Other manufactures use a hydraulic system to push and pull the diaphragm.  Some manufactures of smaller metering pumps do away with a gear reducer altogether and use an electric solenoid stroking mechanism to activate the metering pump piston. Take a look at the cutaway pump shown below to get a visual understanding of how Madden drive systems work.

Motor

Most Madden diaphragm metering pumps use an electric motor for the power to operate the pump.  Stock motors for Madden are from 1/3 HP to 1-1/2 HP, 56 frame, totally enclosed, with both 1/60/115-230 and 3/60/230-460 voltages available.  Special motors are available for a wide range of applications from 50 Hz power to explosion proof and high-altitude installations. 

Output adjustment

Madden diaphragm metering pumps are manually adjustable using a conveniently placed adjustment knob located on top of the pump.  The adjustment goes from 100% down to 0%. For the most accurate volume control 10% is the minimum recommended adjustment setting.  The output adjustment on Madden pumps is a loss of motion type adjustment. This means that for any adjustment setting below 100, the diaphragm is not powered by the piston over a portion of the rotation of the drive shaft.  Some manufactures use a hydraulic drive and reduce the stroke volume in the hydraulic section with a loss of motion action.  There are pumps on the market that offer an adjustable eccentric for controlling the output, and some of these require the use of tools to change the eccentric setting when the pump is stopped.  Electronic solenoid type metering pumps can manually reduce the stroke rate with an adjustment knob, or they can actuate the solenoid with a remote pulse signal.  For information on Madden metering pumps using an automatic output control see the blog Drive Motor Specifying Automatic Metering Pump.  The important thing to know is that the pump you specify will have the capacity in the range of adjustment to accurately pump the required liquid volume, and that the adjustment of volume is easy to accomplish.

For more information on our pumps, take a look at the Madden Pump Selection Guide. If you have an questions, give us a call, or send us a message through our website.  We are always quick to respond.

The post Chemical Metering Pump Diagram appeared first on Madden Pump.

Part of choosing the best pump or chemical metering system is choosing the right accessories. For instance: a pulsation dampener can smooth out the flow of the liquid and eliminate pressure spikes, pressure relief valves can prevent damage to a pump or piping when an over pressure event occurs, back pressure valve can improve pumping repeatability, and a calibration column can help the pump operator precisely measure the pump output once it is put into service. 

Pulsation Dampener

• This device consists of a small vessel with a diaphragm dividing the upper and lower part of the chamber.  Air pressure in the upper section dampens the pressure and flow spike that normally comes with a diaphragm type metering pump.  Elimination of up to 95% of the spike is achievable.  Madden MF Series and JN Series pumps use 10 cubic inch pulsation dampener models, and the MH Series pumps use 36 cubic inch capacity models.  The important element in specifying pulsation dampeners is to make sure the diaphragm and body are compatible with the liquid to be pumped.  Many installations function just fine without a pulsation dampener, but if a smooth injection rate and constant pump discharge pressure are important, for example in a sprayer nozzle application, then including a pulsation dampener can be vital to the performance of the pumping system.  We sell the Blacoh Fluid Control pulsation dampeners which we have found to be economical and reliable in use with Madden metering pumps.

Pressure Relief Valve

• A pressure relief valve protects the pump, pump motor, and discharge piping.  When a set pressure is reached, the pressure relief valve opens and permits a flow of the liquid to a safety containment. This protects the pump and the piping from damage.  In our systems we use adjustable Griffco Valve diaphragm type pressure relief valves.  The important factors to specify are the pressure rating, flow rate range, the materials of construction, and the size of the piping connection.  The adjustable valves will offer an adjustment range, for example from 10-150 psi, and the customer can set the pop off level with an adjustment screw.  The pressure relief valves automatically reseal when the excess pressure subsides.

Back Pressure Valve

• Griffco diaphragm type back pressure valves are adjustable.   The back pressure valve provides an artificial constant pressure for the pump on the discharge side. The constant pressure improves flow control of the pump. This is important when there is virtually no pressure on the discharge side or when the system pressure will be changing from time to time.  Constant back pressure against the pump improves the performance of the pump by making the discharge flow rate more consistent and controllable.  Another use for the back pressure valves is preventing the pump from siphoning of the liquid from the supply tank when the suction head is higher than the pump discharge head.  Again, the important factors to specify are the pressure rating, flow rate range, materials of construction, and the size of the piping connection.  In addition, back pressure valves are normally used in conjunction with pulsation dampeners to improve the performance of the dampener.

Calibration Column

• A calibration column is a clear PVC or glass tube marked with calibrations used to enable the pump operator to precisely determine the flow rate of the metering pump.  The tube is normally installed in the suction piping between the pump and the supply tank.  The calibration column is filled from the supply tank, and the tank is isolated from the pump with valves. The pump is operated using the supply of liquid in the calibration column.  Using a stopwatch and recording the amount of liquid pumped over a short period of time the pump operator can create a pump curve that will show the pumping rate at various pump adjustment settings.  The columns come in various capacity sizes for use with different pump capacities.  To size a calibration column, we select a unit that will hold a minimum liquid volume equal to the maximum pump flow rate for one minute.  In addition to specifying the liquid volume capacity of the calibration column, it is important to select tube and fitting material that will be compatible with the liquid being pumped.

Madden can guide you through the process of selecting the proper accessories for your pump or chemical metering system. If you have not yet determined the correct pump for your project, view our previous article about choosing the right pump or give us a call today 1-800-369-6233. You can also submit a written request for a quote here.

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In our previous news article we discussed things to consider when choosing build materials for the wetted end of your pump. It is important to figure out what materials will be most resistant to the chemical you are pumping, but there are several other factors need to be considered when a specifying a metering pump.

Flow rate requirements

• When choosing a pump, you will need to know the minimum and maximum volume of liquid that needs to be pumped. Madden pumps have a flow adjustment dial.  The normal turndown ratio for a Madden metering pump is 10:1. That means that a pump with a maximum capacity of 60 gallons per hour will be adjustable down to as low as 6 gallons per hour.  If the required flow range is outside the flow rate capacity of any single pump, then multiple pumps may need to be used, one for high flows and one rated for lower flows, to enable the plant to cover all required flow rates.

Discharge Pressure Requirements

• A positive displacement pump, like the Madden diaphragm type metering pump, will be able to push the liquid to overcome system pressure up to the design limits of the pumps.  For example, a Madden model no. MF136C pump is rated for up to 36 gallons per hour, and a maximum discharge pressure of 300 psi with a metal wetted end installed.  We generally limit the plastic wetted end construction to 150 psi.

Liquid Viscosity

• Madden pumps are rated for volume pumping water.  Liquids with viscosity up to 400 cps can usually be pumped successfully with little deterioration in capacity.  If the viscosity is above 400 cps it would be best to contact the factory, and maybe even arrange for some tests, to determine how the higher viscosity will impact the rate of flow that the pump can produce.  Higher viscosity liquids create drag in the piping, and inside the pump, which can reduce the volume of liquid that is pumped.  We should also note that some liquids, such as caustic soda, can change in viscosity with the temperature, and that can definitely impact the pumping volume.

Liquid Temperature

• Madden diaphragm metering pumps work well when the temperature of the liquid is from 30-200 degrees F.  Some plastic wetted end materials of construction, such as PVC, are limited to 140 degrees F.  If your liquid is outside of the normal temperature range noted above contact the factory for assistance.

These are just some of the factors to consider when specifying a metering pump.  We will discuss additional elements in future blog articles.  For additional help in specifying a metering pump to your your application, consult the Madden Pump Selection Guide on our website, call us, or send us an message through our website.  We are always quick to respond.

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