Diaphragm pumps, also known as double diaphragm pumps, are one of the most utilized pumps in the world. Because diaphragm pumps are extremely efficient (up to 97% efficiency) and versatile, they are used in practically every industry that deals with fluids, from ketchup, maple syrup, meat slurries and food-grade water to cement, gel explosives, oil and acids. They’re also designed to deal with extremely viscous fluids. People also love diaphragm pumps because they’re relatively inexpensive to operate and maintain.
Diaphragm pumps are basically positive displacement pumps, like rotary pumps and peristaltic pumps. Instead of an electric motor, diaphragm pumps are compelled by compressed air. The pump chamber has two diaphragms, each with their own inlet and outlet check valve, which move in unison to force the fluid in and then pushing it out. When the diaphragm, which is usually made of rubber, teflon or thermosoftening plastic, moves inward and away from the pump chamber, fluid rushes in as the chamber pressure is lowered. The diaphragm then pushes out into the chamber, increasing the pressure and pushing the fluid out. The air supply is shifted from one chamber to another as both diaphragms push in and out simultaneously.
The size of the diaphragm chamber dictates the kind of fluids it can safely and efficiently pump. Due to the pump’s suction lift characteristics, the size directly determines the pressure and flow rates. Scaled to size, a diaphragm pump can handle water and sludge, all the way to viscous liquids like syrups and slurries. Diaphragm pumps are even used in making artificial hearts, as the mode of action is similar to a human heart’s.
Diaphragm pumps are extremely versatile, and can be fitted to pump virtually almost any kind of fluid. While the most common applications of diaphragm pumps are for moving water and other light fluids, many other industries like petrochemical, construction, mining, printing, food and beverage and pharmaceutical industries have found many uses for diaphragm pumps. If an industry is involved with fluid transfer, then they are most probably using diaphragm pumps. Diaphragm pumps are also used for producing pressure for spraying and cleaning.
Diaphragm pumps have a lot of advantages over other positive displacement pump designs. Here are some of them.
Little to no electricity
Since diaphragm pumps are driven by compressed air, they require little to no electricity to function. No electricity means they can be used in industries and environments where the presence of electricity is too dangerous.
The same reason why diaphragm pumps don’t require electricity to function also makes the pump incredibly easy to set up and operate. There are no electrical systems or complicated wiring whatsoever, making diaphragm pumps easier to use than other pump types.
While many pump types like centrifugal pumps and magnetic drive pumps can not run dry without incurring damage or causing issues, not only can diaphragm pumps run dry, they are also self-priming.
Pump viscous liquids
Many pumps can only deal with thin fluids like water and will break down or stop working if subjected to thick fluids. Diaphragm pumps, on the other hand, can deal with most viscous liquids, thanks to its double chamber design. This also makes diaphragm pumps one of the most versatile pumps available.
Handle abrasive materials
Diaphragm pumps, thanks to their solid construction, can handle corrosive fluids like acids and abrasive materials like cement slurries and Portland mixtures. Any fluid, regardless of viscosity and substance, can be pumped by a diaphragm pump.
Safer than most pumps
No running motor, no packing and no seals mean that diaphragm pumps are practically immune to fluid leaks that are common with many other centrifugal pump designs. This makes diaphragm pumps good for handling corrosive and volatile fluids that may be deadly or dangerous if released.