Sometimes pumping is complicated. One way to make it easier is to choose an air-operated double-diaphragm (AODD) pump. With the support of experts like your manufacturer and distributor, an understanding of AODD pumping basics, and answers to some frequently asked questions, you’ll be prepared to optimize an AODD pump in various mining applications.
Here, we’ll address the most common questions Versamatic experts receive about AODD pumps in mining applications.
How can AODD pumps be used in mining?
When it comes to mining, dewatering and ore processing are the two most common applications where you’ll find Versamatic pumps. But there are other ways to use an AODD pump in a mine. These include the general transfer of chemicals and fluids used for equipment maintenance, filtration, pumping explosives, shotcrete pumping, and more.
What pump materials are best for mining?
Maintenance managers and process engineers who work in mining commonly know pump specifications like the size and flow rate they need for an AODD pump, but they often have questions about which materials of construction to choose.
The answer is “it depends,” but it starts with what fluids you’re pumping. With dewatering, for example, the acidity of the mine water drives your decision. If your pump is above ground and being used on the process side, the harshness of the chemicals is your top consideration.
In any case, a manufacturer or distributor representative can walk you through a few factors to help you select the right pump body material and elastomer materials based on the properties of what you’re pumping.
Fluid factors to consider when choosing pump materials include:
- Acidity/pH level
- Temperature
- Abrasiveness
- Viscosity
Mobility requirements are another consideration. If you need to move your AODD pump around, pump weight is critical. So, depending on the fluid you’re pumping, you may choose a polypropylene or aluminum pump rather than a heavier cast iron pump.
Are AODD pumps portable?
Yes, AODD pumps are portable, and much moreso than most electric and centrifugal pumps. See the question above for advice about choosing the best pump material for a mobile pump. One of the primary benefits of AODD pumps as opposed to other types of pumps is that as long as you have an air source, you can move your pump around without an electrician or technician of any kind.
Are AODD pumps safe for mining?
Yes. Because AODD pumps are pneumatic (air-operated), they don’t require electricity, which can be hazardous in wet or potentially explosive environments like mines.
Some applications, such as coal mining, require ATEX-certified pumps. ATEX is a European conformity standard for equipment used in explosive atmospheres. Versamatic AODD pumps conform to ATEX regulations, meaning they meet stringent safety requirements.
Can you control the flow rate of an AODD pump?
Yes. AODD pumps offer variable flow rates. Let’s say the mine is gushing water or has low seepage, you can vary the speed of the pump to accommodate your needs. For example, you can run a 3-inch pump anywhere between 15 gallons per minute up to 280 gallons per minute. That’s not doable with many other types of pumps. Your options to control the flow include giving the pump less air or closing off the discharge valve.
Can AODD pumps run dry?
Yes, AODD pumps can run dry because they don’t rely on mechanical seals. Rather, they employ diaphragms, which pump the liquid back and forth.
In fact, if you do run an AODD pump dry, there's no heat generated in the pump, so you don’t run the risk of damaging the seals like you might if you allowed an electric submersible pump to run dry. It is, however, not recommended to continuously run your pumps dry as it will continue to wear on the internal parts as it would if you were pumping under normal conditions.
Can AODD pumps handle solids, slurries, and suspended solids?
Yes, diaphragm pumps can easily handle solids, slurries, and suspended solids in various mixtures and viscosities. Talk to one of our expert distributors to determine which pump is right for your particular application.
Can AODD pumps run against a dead head or closed valve?
Yes. As soon as the discharge pressure exceeds the air input pressure, the pump will stop cycling. Once you release the pressure on the discharge side, the pump will cycle again.
How do you extend the life of an AODD mining pump?
There are several ways to improve your mining pump’s lifespan. The first is by controlling the air quality going into the pump. Often mine air is wet or dirty, so anything you can do to improve the compressed air source will help the longevity and reliability of the air side of the pump.
On the fluid side, diaphragm life is the biggest concern. If you starve the pump, your diaphragm life will be poor, so it’s important to have a suction hose that matches or exceeds the pump size. For example, a 2-inch pump should have a 2-inch or larger suction hose. If you add a suction screen to keep debris out of your pump, be sure to clear any clogs regularly to improve diaphragm longevity.
Another way to extend the life of your pump is not to run it 24/7 if you can help it. Although you can let an AODD pump run dry, any time the pump cycles, it creates wear and tear on the valve and diaphragms, shortening their lifespan.
Finally, it’s important to remember that AODD pumps are more effective at pushing fluid out than they are at pulling it in, so it’s beneficial to shorten the suction line. If you have more distance to cover, make up for it in the discharge line. Long suction lines reduce the life of your diaphragm and may prevent your pump from priming.
How much does an AODD pump for mining cost?
There are many variables that affect pump cost for mining. These include the market you’re in plus the pump options you choose, such as:
- Size
- Material
- Style (ball-valve or flap-valve)
In any case, your trusted local distributor will be able to assist you with selecting the right pump at the price point that meets your budget.
Will running an AODD pump at a higher air volume be more expensive to run and maintain?
The short answer is yes. AODD pumps are positive displacement pumps, so if they are running flat out they will lose efficiency. The key to optimizing pump performance is finding the right pump for the right application, and that’s why we recommend selecting a bigger pump and running it slowly versus a smaller pump and running it fast. While your initial investment may be somewhat higher to purchase a larger pump, the best return on investment is to run your pump in the middle of the flow curve whenever possible. In most cases, going up one pump size (e.g. from a 1.5-inch pump to a 2-inch pump) will ensure you see a return on your investment in terms of pump longevity and reduced air consumption.
Is it difficult to install an AODD pump?
No. AODD pump installation is easy. Simply add your suction and discharge fittings, hook it up, and you're ready to go. You don't need a special certification. You don't need electricians or other technicians. You don't need controls other than maybe a valve if you choose to have one. Also, your local distributor can make pump installation even easier. They have the knowledge and experience in mining applications to help you get up and running. They can even recommend accessories — such as screens, hoses, air controls, filter regulators, valves, and more — to help you get to work quickly and optimize performance over time.
As always, if you have questions about AODD pumping in mining applications, please contact Versamatic or your local distributor.
