Your fermenters and bright tanks are constantly subjected to pressure changes. Routine activities such as brewing, fermenting, cleaning-in-place, and moving product can potentially cause a poorly vented tank to implode. It is important to understand how and why vacuum failure occurs so that you can maintain the operation of your tanks.
What is Vacuum Pressure?
Vacuum pressure occurs when your tank is poorly vented or if the relief valve is malfunctioning. This results in a drop in pressure within your fermenter or bright tank, creating a pressure differential between the internal pressure of the tank and the atmospheric pressure. When this pressure differential exceeds the external pressure rating of the tank, it can lead to catastrophic failure. This often results in a complete loss and high replacement costs.
How Does Vacuum Failure Happen?
The risk of vacuum failure in a brewery is very real. Many everyday tasks in your operation can directly contribute to vacuum failure. These activities include:
Pumping or draining an unvented tank
When you pump or drain a tank without allowing air to enter, the beer is removed but the tank doesn’t fill with air. As the tank continues to empty, the small amount of CO2 or air inside needs to fill the void left by the beer. This creates a low-pressure environment in the tank, and the weight of the atmosphere causes the tank to implode.
Overfilling a Tank
If you overfill a fermenter or bright tank to the point where the beer fills the vent line, a siphon can be created. Similar to pumping or draining an unvented tank, the beer will flow out through the siphon without allowing air to enter the tank. Once enough beer has been siphoned out through the vent line, the tank will collapse under the atmospheric pressure.
Hot CIP followed by cold rinse
After cleaning a fermenter or bright tank, the air inside the tank becomes very hot. If the rinse water temperature is too cold, it can cause a rapid drop in pressure within the tank because cold air is denser than hot air. When the temperature inside an unvented tank rapidly decreases, it can implode instantly.
Using Caustic Soda After Fermentation
It is common practice to clean a fermenter after transferring the beer to a bright tank. During fermentation, CO2 is produced as a byproduct. If you introduce caustic soda to a fermenter that still contains CO2, a chemical reaction occurs, converting the gas CO2 into a solid. This reduces the pressure inside the fermenter, which can lead to vacuum failure if the tank is not properly vented.
ACE Fermentation Tank with Vacuum Relief Valve
The Importance of a Vacuum Relief Valve
A vacuum relief valve protects your tanks from vacuum failure by allowing air to enter when the internal pressure drops. Your fermenters and bright tanks are valuable investments for your brewery. Not only are they expensive, but they also enable you to produce the beer that your customers love. The best way to ensure the continuous operation of your tanks is to install a properly sized vacuum relief valve.
Choosing the right-sized vacuum relief valve is crucial. They are not one-size-fits-all. Since tanks are engineered differently and breweries have variations in their cleaning processes, the valves are typically sized to fit your specific application by the valve manufacturer.
Inspection of Vacuum Relief Valves
Your vacuum relief valves are only effective if they are functioning correctly. Regular inspections are essential. During the initial usage phase, you should inspect the valves more frequently than you think is necessary. The goal is to identify potential issues before they become significant problems.
When inspecting your valve, ensure that it is being properly cleaned during clean-in-place procedures and that it can still operate mechanically as intended.