What Is a Rotary Blower?

Patrick Roland
Patrick Roland
Man with a drill
Man with a drill

A rotary blower is a popular method for pumping liquids, powders and gases for industrial purposes. There are several types of blowers, but each utilizes centrifugal force in order to aid pumping. These inventive machines are an important part of many utilities and productions that help everyday life.

Rotary blowers feature two to three spinning rotation devices known as lobes that help create compression. These figure-eight shaped, smooth gears turn within a metal housing and create pockets of air that develop a vacuum effect. Every rotary blower has an input and output tube for whatever material is passing through. The vacuum pressure created sucks the input material into the blower and forces it into the output tube and through the tube until it reaches its destination. Blowers come in many sizes and strengths to accommodate different needs.

A rotary blower primarily is used to transport liquids, gases and powders. There are three basic types of blowers, including the roots rotary blower, the rotary lobe blower and the rotary positive blower. Each is used for different means and offers distinct advantages over the others.

A roots rotary blower is one of the most commonly known types, especially to automobile enthusiasts. Featuring twin lobe rotation, this blower is commonly found in engines to provide more horsepower. This blower type focuses on providing a larger amount of oxygen to the engine, thus increasing combustion and providing an automobile with more power and speed. Though this is a sought-after element for many engines, it is the least fuel-efficient type of blower and is known to get quite hot during use.

Rotary lobe blowers are another commonly used type of rotary blower, but most people never see them in action. One of the biggest uses of this type of machine is in water processing plants. These strong, silent suction devices are used, for example, in transporting a collection of water into a treatment plant for filtration. These are known to be among the largest blowers in use.

Rotary positive blowers are among the most delicate types of blower. This stems from the primary use as a pneumatic transport for powders and grainy materials. These blowers are commonly found in production and manufacturing facilities that deal with fine elements that must be kept in a controlled environment. An example of this type of blower would be a flour company moving the white powder from storage to the packaging stage.

What Is a Rotary Piston Blower?

Simply put, a rotary piston blower uses centrifugal forces to produce airflow. Its design was an improvement on the traditional prior art rotary blower. The previous version used rotating pistons to generate air, but it required more moving parts and could break down easily. It also used lubricant to minimize friction.

In contrast, a rotary piston blower has fewer moving components and seals. This new design features an elongated drive shaft plus two pistons, two timing gears and a piston housing. Because moving internal parts do not touch each other, no lubricant is needed. Thanks to the simplicity of its design, it's also easier to manufacture and breaks down less frequently than its predecessor. The first international patent for a rotary piston blower was filed in 1999 by Ballard Power Systems, a Canadian manufacturer that develops proton-exchange membrane fuel cells.

Rotary Piston Blowers and Fuel Cells

Before learning about the basics of a rotary piston blower, you need to understand how fuel cells function. That's because rotary piston blowers are critical to fuel cell operations. The cells require oxidants — oxidizing agents that react with other substances and accept some of their electrons.

Fuel cells contain electrodes, both an anode and a cathode, which are covered in a metallic catalyst such as nickel or platinum. Some types of fuel cells require oxidants such as oxygen to generate power. First, fuel is oxidized by the anode to produce electrons flowing to the cathode and then an external circuit. Those same electrons reduce the oxidant at the cathode. This process sends electricity to a wide range of machines: passenger vehicles, aircraft and electrical devices to name a few. Fuel cells also generate heat in the process, which can be harnessed to provide indoor heating.

How Blowers Help Fuel Cells Work

Fuel cells come in a wide range of designs. The most common types are hydrogen and direct methanol fuel cells. Both of these require an oxidizer to work. Along with continuously supplied hydrogen or methanol fuel, an oxidant is necessary to power the electrochemical reaction that generates electricity.

So what do rotary piston blowers have to do with fuel cells? Well, these machines help channel oxidants into each fuel cell. What's more, the oxidant stream supplied to the fuel cell is free of oil. This ensures that the fuel cell functions as expected.

What Are the Different Types of Rotary Blowers?

As mentioned earlier, there are a few different kinds of rotary blowers. The terms "rotary lobe blower" and "Roots blower" are often used interchangeably. Both refer to positive displacement blowers that were developed in the 19th century by Philander and Francis Marion Roots. founders of the Roots Blower Company. Their initial version used a rotor with two meshing lobes and pumped air into blast furnaces used in smelting operations.

The Roots brother's first invention is the predecessor of all rotary blowers in use today. Some use a two-lobe design, while others use three-lobed rotors to channel air out. The original prior art rotary piston blower is also a descendant of the original lobe blower. The newly designed rotary piston blower works on a similar principle.

Where Can I Buy a Rotary Lobe Blower?

Rotary blowers are commonly used in industrial settings. Besides providing consistent airflow to fuel cells, rotary blowers are also found in automated milking machines, plastic processing, gas collection, material vacuuming and many other applications. You're most likely to find rotary blowers for sale from industrial and agricultural equipment suppliers. You should also check with specialized vendors that only sell blower machines, parts and supplies.

Discussion Comments


I maintain rotary vane blowers for a large food manufacturing company. The factory makes bread, pasta, and other grain products, so we have several of them through out the buildings. They do a really good job of moving the product around, but they are definitely cranky.

You have to keep careful watch on the adjustment of everything, fluid levels, and operating temp. That only makes sense, though, when you have a machine moving around so much tonnage every day.


The factory where I work has a centrifugal blower as part of the material transport system. We move a huge amount of product every shift, and this is the quickest way we've found to do it. The old system was a lot slower, and we've really increased productivity since the update. I don't even want to know what it cost, though.


I had a blower on my old Chevy Barracuda. It made an insane difference in the level of power. With that thing turned on, the car really wasn't even safe to drive at top speed. We usually took it to the track to do stuff like that.

It's funny how such a simple idea, forcing more air into the engine, can make such a difference in the performance. It also turned it into a complete gas hog. Miles per gallon was never that car's strong suit in the first place, but it went down to only 8 or 9 mpg with the blower engaged. Not what you'd call a daily driver.

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