When it comes to selecting air-operated double-diaphragm (AODD) pump materials, there are some rules of thumb.
Contact us to discuss your requirements of 3/8 Inch Aluminum Diaphragm Pump. Our experienced sales team can help you identify the options that best suit your needs.
For example, metal AODD pumps are commonly used in high-pressure applications and environments that require grounding. Stainless steel, in particular, is a go-to choice for food and personal care applications due to FDA requirements. On the other hand, plastic AODD pumps are frequently used in chemical and petrochemical applications because they resist corrosion.
With consumable parts and accessories such as diaphragms, valve balls, valve seats, and valve seat o-rings, it all starts with chemical compatibility. For instance, FDA-compliant Hytrel is typically used for food processing.
It’s important to remember these are not hard-and-fast rules. Selecting an AODD pump is more complex than following any one general piece of advice. The decision often requires the process of elimination starting with the material you’re pumping, then accounting for your budget and other factors.
While selecting the right materials for an AODD pump is nuanced, it doesn’t mean you’re on your own. Versamatic application engineers and distributors are always available to help you choose the right diaphragm pump materials for your operation.
We wrote this blog post as a guide to common questions about AODD pump material selection.
The short answer is “it depends.” The Versamatic team has answered this question countless times — so much so that we’ve consolidated our knowledge into an invaluable online Pump Selection Tool. With basic information such as fluid type, desired flow rate, and more, this tool helps you narrow down your choice of pumps to best meet the need of your specific application.
Pump users should start by knowing the following four characteristics of the fluid they’re pumping: chemical compatibility, temperature, abrasiveness, and viscosity. Refer to your pump manufacturer’s chemical compatibility guide as a starting point.
Certifications are another important consideration. For example, is your pump ATEX certified (this is a common requirement in mining)? Or, do you need to ensure you’re using FDA-approved materials? Those questions will often drive your pump casting material and elastomer selections.
AODD pumps come in two main casting options: metal and plastic. Metal options include aluminum, cast iron, or stainless steel in clamped construction and aluminum or stainless steel in bolted construction. Plastic AODD pumps are constructed of polypropylene, PVDF, and conductive polypropylene.
The benefits of metal AODD pumps include:
Plastic AODD pump benefits include:
AODD pump diaphragms, balls, seals, and valves, also known as elastomers, come in a variety of materials. Knowing which one is right for your application is more complicated than the metal vs. plastic discussion. You must account for the price point, temperature, chemical compatibility, abrasiveness, flex life, and other factors.
Need assistance making your selection? You can read about material properties on page 10 of the Versamatic catalog or refer to the Materials Selection Guide below. Of course, you can always consult with your authorized Versamatic distributor or one of our application engineers.
Diaphragm-40˚F/-40˚C
D $$$ Hytrel® B+ A+ B 220˚F/104˚C -20˚F/-29˚C A $$ Neoprene D B C 200˚F/93˚C -10˚F/-23˚C A $ Nitrile C+ B C 190˚F/88˚C -10˚F/-23˚C A- $ PTFE A+ F A+ 220˚F/104˚C -35˚F/-37˚C C- $$$ Santoprene® A A+ A+ 275˚F/135˚C -40˚F/-40˚C A+ $A+ = Best; F = Not recommended
$ = Least expensive; $$$ = Most expensive
Santoprene® is a registered trade name of Exxon Mobil Corp. Hytrel® is a registered trade name of E.I. DuPont.
Generally speaking, small plastic pumps are more affordable than small metal pumps, while large metal pumps are more affordable than larger plastic pumps.
Assuming your fluid and your pump material are chemically compatible, metal pumps will generally last longer than plastic pumps. Plastic is flexible so over time plastic pumps may get weaker, whereas metal is more rigid and retains its strength.
Metal is the best choice for high-pressure pumping applications due to its rigidity. Plastic pumps are generally rated to 100 PSI inlet or discharge pressure; metal pumps are generally rated to 125 PSI or higher.
Volume is more about your pump size rather than the material you choose, assuming your pressure is equal and within safety ratings. A 3" plastic pump can pump the same volume as a 3" metal pump.
Affordable, lightweight aluminum is the most common selection for mine dewatering.
Pump users in this category typically choose aluminum AODD pumps.
Aluminum is the most common material chosen by pump users in the ceramics market because it handles abrasive substances well.
The most common material choice for the lubricants market is aluminum.
Aluminum AODD pumps are popular for marine applications, such as pumping water on a vessel before it goes back into the ocean.
The food processing industry has strict material contact standards, such as
EU Regulation 1935/2004. To comply, food processing pumps are typically constructed of stainless steel and use Hytrel or Teflon (PTFE) for elastomers.
In mining, pump mobility and weight are often key factors in pump selection. For that reason, polypropylene or aluminum pumps are both good options.
Standard metal ball valve pumps are frequently used in CBD production; polished FDA-compliant units are also available.
Do you have a pump material question we didn’t address above? Don’t hesitate to get in touch. The team at Versamatic is always happy to help you troubleshoot any AODD pump issue you run into and find the right pump materials for your operation.
Before choosing the best air-operated double-diaphragm (AODD) pump materials for your application, these fluid characteristics must be considered: temperature, abrasiveness, viscosity and overall chemical compatibility.
Selecting the right materials for an AODD pump is an essential step in achieving maximum performance and safety. Understanding the diaphragm pump material selection process will help decrease downtime while increasing reliability, performance and profitability.
Click the links below to learn more about each characteristic to consider when choosing pump material:
Diaphragm pump material selection is critical to its cost and durability.
First, make sure that the fluid you're moving is chemically compatible with the pump materials. This includes elastomers, castings, and possibly hardware if there are plans to submerge the pump. To do this, consult your AODD pump manufacturer’s chemical compatibility guide.
The fluid and air sides of the pump are separated by the seal created with the diaphragms. It is critical to confirm the chemical compatibility for both the AODD pump’s wetted casting or pump body (chambers and manifolds) and the pump’s seals (diaphragms, valve balls and manifold seats/seat seals).
For more how do piston water pumps workinformation, please contact us. We will provide professional answers.
In many cases, there can be multiple materials that are chemically resistant. If this is the case, you want to understand the other fluid characteristics and how the pump will be used. For example, if you’re pumping an abrasive product, choose castings and elastomers that effectively handle abrasive products. If the fluid is flammable, choose a material that can be grounded, like a metal ATEX model. Sometimes it just comes down to cost. For example, PVDF (Kynar®) can handle most chemicals but is more costly than polypropylene. So if polypropylene is chemically compatible, you might select the lower-cost pump construction.
For the pump’s air side, select a chemically compatible material with the fluid being pumped.
The fluid being transferred doesn’t only contact the wetted side of the pump. The fluid is certain to encounter the air side of the unit, either via the environment around the pump or when a diaphragm fails. Many times, the surrounding environment can have chemical fumes, or the process in which the pump is installed can drip or splash chemicals during transfer. If that is the case, you need to make sure the air side (air valve, center block, air chambers, etc.) include chemically compatible materials of construction.
This is also true when a diaphragm failure occurs. When a diaphragm fails, the liquid can contact the pump’s air side. If not compatible, this can cause issues with the main air valve and pilot valve, as well as other systems tied into the same airline.
Using chemically compatible materials on both the air and wetted side will extend the life and performance of the pump and, in most cases, will be worth the additional upfront cost associated with some air side materials (such as stainless steel).
If you’re pumping abrasive material, you may want to choose harder casting and seat materials. Both stainless steel and cast iron are great metal pump options for combating premature wear due to abrasives, while PVDF is best for plastic pumps in abrasive applications. If you’re questioning the effectiveness of a specific material, consult the AODD pump manufacturer for assistance.
AODD pumps can handle a wide range of temperatures: cold fluids (consult factory when pumping fluids below freezing) and fluids up to 220 degrees Fahrenheit (104 degrees Celsius) and beyond. When exceeding 220 degrees Fahrenheit (104 degrees Celsius), consult the factory for guidance.
Viscosity of fluid being pumped is important to understand as it has a direct correlation to performance and material choice. For higher viscosity (thicker) products, heavy valve balls like stainless steel or PTFE might be needed in order to rise and fall in the thick fluid. This allows the pump to operate as intended. Lighter materials, like Santoprene, might not work as well with thick products as they have a tendency to float, affecting flow and pump performance.
AODD pumps do not require electricity to run. Instead, they require compressed air. Due to the reciprocating movement of the diaphragm rod and potential for static build-up, AODD pumps with the proper provisions can be grounded for safe, reliable operation in explosive environments. This is critical when pumping flammable liquids or when a pump is in an environment where fumes are present.
If an AODD pump is going to be used in a portable application, users might choose a lighter material if a cart or dolly is not an option. Specifically, in underground mining, AODD pumps are moved by hand, so weight is a big factor. Many customers will choose a lightweight plastic or aluminum unit over a heavier cast iron or stainless steel body. Some may use a smaller pump, like a 1 ½” or 2” unit instead of a 3”, which is considerably heavier.
When purchasing a pump, you need to understand if the pump will be installed inside a facility or out in the elements. This is important for several reasons.
If the pump is to be installed in direct sunlight, you may choose a metallic unit over a plastic one. Over time, UV sunlight can break down plastic components, causing it to become brittle, potentially leading to issues.
Another factor is cold temperatures. If the pump experiences temperatures below freezing, make sure the fluid being moved is flushed. If the fluid freezes in the pump, it can damage castings and/or diaphragms. Alternately, heat trace is a common addition to piping and pumps that helps prevent freezing in harsh environments.
Some applications, like food processing or personal care products, may require the surface finish to meet a specific smoothness. For example, 3-A certified units used to pump dairy products require a 32µ-in (Ra 0.8 µ-m) surface finish or better. On the other hand, an FDA-type application may require a less polished finish depending on how the pump is to be cleaned and sanitized.
Each of the commonly offered diaphragm materials come with varying attributes. When applied correctly, these attributes can increase the MTBF (Mean Time Between Failure), ultimately reducing downtime. Below are some attributes about each elastomer or thermoplastic to consider when selecting them.
Rubber Materials (Diaphragms, Valve Balls, Seat/Seat Seals)
Thermoplastic Materials (Diaphragms, Valve Balls, Seat/Seat Seals)
PTFE (TF)
The material chart below offers you guidance when selecting the materials within your pump.
Ultimately, it’s a balance between chemical resistance at a higher cost versus flex-life at a lower cost. In many applications, Santoprene is a very effective material because it offers much of the chemical resistance of PTFE, excellent flex-life and is very cost-effective. However, it has some chemical limitations, so check the chemical compatibility guide when making your choice.
Each of the commonly offered diaphragm materials come with varying attributes. When applied correctly, these attributes can increase the MTBF, ultimately reducing downtime. Below are some attributes about each casting material to consider when selecting them.
Metal Casting Materials (Fluid Chambers, Manifolds, Seats, Diaphragm Plates)
Plastic Casting Materials (Fluid Chambers, Manifolds, Seats, Diaphragm Plates)
Some users find value in standardizing on one pump model to handle all needs of their plant. The initial investment may be greater upfront for an AODD pump that is PTFE-fitted, but might save you in the long run for the following reasons:
If initial cost is a driving factor in the decision-making process, when researching AODD pumps, evaluate all the materials that will work, then select the least-cost combination. Generally, aluminum casting pumps fitted with Nitrile elastomers is a reliable, low-cost option.
If the pump needs to carry a specific certification, make sure it’s available in the material options that you are looking for. If a pump needs to be 3-A, for example, there will be a limited amount of available material options. Consult the AODD pump manufacturer for details.
Mixed Material Pumps
Some users find that mixing materials within the pump offers them the best overall performance. For example, some users will choose heavy PTFE valve balls in a Santoprene-fitted pump because the PTFE balls work well when pumping thicker viscosity products. Some may choose a hard valve seat like stainless steel in an aluminum pump to deal with abrasive materials. These models may not show in the standard price book but are available for purchase. Remember, you can always contact the AODD pump manufacturer for guidance.
Choosing the right materials for your AODD pump during the selection process can make all the difference in your safety and satisfaction. For additional information on selecting the AODD pump that is right for your application, please contact us today.
Find these tips useful? Share which tip helped you the most in the comments below.
If you are looking for more details, kindly visit Pneumatic Piston Pump.
permanent magnetic generator all-in-one c&i ess system customize frac proppant fabrication fracking ceramic proppant exporter 150w poly solar panel manufacturer 800 kw generator battery energy storage system—outdoor suppliers china ceramic proppant exporter frac sand vs ceramic proppant stackable lithium battery 51.2v 304ah diy empty battery pack box ceramic coated proppant manufacturing stackable lithium ion battery Charging Pile ceramic coated proppant fabrication visit our website