Graco AODD Case Study- Counter Pressure Beer Filling

In today’s post, we’re going to take a look at an application we’ve recently been helping a few different customers with- counter pressure beer canning. Increasingly, we are recommending people use Graco’s FG Series Air Operated Double Diaphragm pumps for these applications. So what is counter pressure beer filling and why are Graco AODDs perfect for these applications? Let’s take a closer look.

To start, let’s begin with a general overview of beer filling/canning technologies in the craft brewing space. While historically craft breweries relied on draft and taproom sales, the COVID-19 pandemic totally changed the game. All of a sudden, everyone needed to figure out how to get their beer into cans. There are two primary filling or canning types- gravity and counter pressure filling.

In line gravity filling

On a gravity filler, beer is supplied to the filler directly from the brite tank and relies on head pressure and liquid temperature to control fill. While we do use CO2 to purge cans and lower oxygen levels, because the can is open to atmosphere, foaming can be difficult to control. This is especially true with increasingly highly carbonated products like seltzers.

Counter pressure fill bowl

With a counterpressure filler, we pump from the brite tank into a pressurized bowl on the filler. Fill heads then lower onto cans and seal it from the outside. Cans are purged and subsequently pressurized with CO2, sealing them from the environment. This is important because the solubility of a gas in liquid is directly proportional to the pressure of the gas above the liquid. By keeping the pressure constant throughout filling, we’re able to keep CO2 in solution and maintain carbonation levels and prevent over foaming.

Historically, craft breweries have used gravity fillers because of their lower cost and wider availability. That’s beginning to change as counter pressure filling has scaled down and more OEMs offer a solution at a price point attractive to smaller breweries.

So what does this mean for pumps? Well, as mentioned above, it means we need to get a pump that can feed a pressurized fill bowl. While the workhorse of the craft brewery has historically been the centrifugal pump, we typically can’t develop the pressures needed to feed the fill bowl with one.

So that puts us into a PD type pump. Looking at our toolbox, we have two primary options- a Waukesha rotary lobe or a Graco AODD.

While the Waukesha Universal pump could do the job, there are a few drawbacks. For one, we have overall footprint. Typical Universal 18 or 30 pump assemblies will be between 36” and 60” long and 24” to 36” wide. Rotary lobe pumps also rely on a mechanical seal, which means an opportunity of oxygen pickup. We also have to be careful not to dead head them. They also require 3 phase power, which not all breweries have readily available. Finally, a PD pump assembly isn’t cheap- costing typically between $10,000- $12,500 after adding gearmotor, base, and variable frequency drive.

Note the Graco 515 feed pump

Graco’s FG series of AODD, on the other hand, are extremely compact and easy to use. Simply connect your hoses, connect air, and away you go. We also don’t have to worry about deadheading an AODD. And there is no mechanical seal to allow any oxygen in. The push/pull action of an AODD is also low shear and gentle on beer. Finally, a Graco FG series pumps is about 1/3 the price of a comparably sized rotary lobe assembly.

So whether you’re a brewer trying to decide between counter pressure and gravity fill or you’re an OEM designing the latest and greatest counter pressure beverage filler, consider a Graco AODD. Not only is it compact, easy to use, and economical, Graco’s AODDs are gentler on beer and eliminate at least one source of oxygen pickup, while still handling the higher pressures needed for counter pressure beer filling.

And as always, if you have any questions about any of your beer or high purity fluid handling applications, contact a Triplex Sales Engineer today!

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