Guide: How vacuum technology is used in the process industry

What do milk powder, beer and medicines have in common?  

They are all examples of media that can be handled through vacuum applications – from filling and evaporation to sterile processes. 

Vacuum is a key technology in the process industry because it enables pressure conditions to be controlled, allowing liquids to be transported and processed gently, the boiling point to be lowered, and the shelf life of foodstuffs to be extended through oxygen-free packaging. 

In this article, we launch a new series that gives you an overview of the most important things you need to know about the subject. We’ll start by looking at the physics behind vacuum technology and explore the challenges that vacuum technology can help solve in breweries, dairies and pharmaceutical production.  

Ready to be sucked into the topic? Let’s get started! 

A vacuum occurs when the pressure inside a system is lower than the atmospheric pressure outside – approx. 1,013 mbar (millibars) at sea level. As the absolute pressure is reduced, fewer and fewer gas molecules remain in the system – and the vacuum thus becomes “deeper”. In practice, this means that the medium behaves differently. For example, water boils at 100°C at normal pressure, but as early as around 50°C at approx. 100 mbar. The lower the pressure, the lower the boiling point and the easier it is for liquids to evaporate. This makes it possible to dry, concentrate or dehumidify products more gently and energy-efficiently. 

In the process industry, two types of vacuum are typically used: 

• Rough vacuum (approx. 1,000 – 1 mbar) is used for oxygen-free transfer, vacuum packing, foam-free filling, casting and de-moulding, etc. 
• Fine vacuum (typically below approx. 1 mbar) is used in more advanced processes such as evaporation and drying of heat-sensitive media, where very low pressure and lower boiling points are required. 

The two levels indicate how far the pressure is reduced below atmospheric pressure, measured in mbar. Rough vacuum is closer to atmospheric pressure, whilst fine vacuum involves significantly lower pressure and thus a greater impact on the process – particularly in the form of lower boiling points. 

Vacuum is therefore not about creating a perfect vacuum, but about controlling the pressure precisely according to process requirements. If you operate at a lower pressure than the process requires, you are wasting energy maintaining the vacuum. Correct system sizing ensures both a stable process and lower energy consumption. 

But what does this mean in practical terms for your production? Vacuum can solve a number of challenges, which we outline below. 

Whether you produce beer, milk or medicines, oxygen is a major challenge. If the product comes into contact with oxygen, it can oxidise. And once the damage has been done after production, it cannot be rectified. 

In the brewery, the solution is to keep the product completely shielded from atmospheric air throughout the entire process. The tanks are flushed with CO₂ before the beer is pumped in, and bottles and cans undergo the same procedure before filling, so that the beer is never exposed. 

In the dairy, the challenge is different, but the consequence is the same. The air dissolved in raw milk must be removed before homogenisation, otherwise it promotes oxidation and causes unwanted foaming in the final product. And the stricter the sterility requirements, the more essential the control of oxygen becomes. In the pharmaceutical industry, vacuum is the barrier that ensures your product is clean and oxygen-free before it is sealed inside the sterile ampoule or infusion bag. 

High temperature is the classic trade-off in food and pharmaceutical production. Heat kills bacteria, but can also degrade proteins, vitamins and active ingredients. Vacuum solves this dilemma by lowering the boiling point and working temperature in all processes involving evaporation or drying. 

Take the dairy as an example. When you concentrate milk, this typically takes place at 60–70°C under vacuum, rather than the 100°C required at atmospheric pressure. This temperature difference is directly reflected in the nutritional content and quality of the end product.  

In the brewery, the requirements are different, but the principle is the same: vacuum evaporation during wort cooling rapidly lowers the temperature whilst completely removing unwanted flavour compounds without negatively affecting the taste. 

At even lower temperatures, freeze-drying is used in the pharmaceutical industry, where the benefits of vacuum become clearly apparent. Under high vacuum, water sublimates – that is, it changes directly from a solid to a gas without passing through a liquid state. The biological drug is preserved almost unchanged. 

Contamination is one of the greatest risks in production. A foreign body in a pharmaceutical product, a bacterium in pasteurised milk or an oxidised batch of beer costs more than just the discarded batch. It can also cost you the trust of your customers as a manufacturer. 

Vacuum is used to prevent precisely that. Transport and handling take place in closed systems at a lower pressure than the surrounding environment, so that the product does not come into contact with dust, bacteria or oxygen from the air. 

If a leak occurs, air will be sucked into the system rather than the product escaping. This makes the process easier to control and reduces the risk of contamination. During sterilisation, the air is removed from the chamber so that the steam can reach all surfaces. 

In the dairy and brewery, you’ll find the same principle: closed transfers from tank to tank act as a barrier against anything that doesn’t belong in your product – whether it's bacteria in the pasteuriser or atmospheric air in the fermentation tank. 

Vakuum er det modsatte af traditionelt tryk. Hvor en trykslange udvides indefra, udsættes en vakuumslange for et konstant atmosfæriske overtryk udefra. Det samme gælder for koblingerne i systemet. Valget af komponenter er både vigtigt for driftsforholdene og jeres produktsikkerhed. 

I jeres vakuumapplikationer er det vigtigt, at slangerne har en indbygget spiral. Den sikrer, at slangen bevarer formen under undertryk. Uden den risikerer I kollaps og blokeret flow i jeres anlæg. 

Hvis du skal etablere et vakuumsystem, findes der et udvalg af slanger, som klarer opgaven. Blandt vores sortiment anbefaler vi: 

• Durable PU hoses: This is one of the most common types of vacuum hoses for transporting dry media such as granules and powders. As a material, polyurethane combines high flexibility with extreme wear resistance, ensuring the hose retains its shape and integrity throughout the entire process line. 
• Hygienic silicone hoses: In environments where cleanliness and temperature stability are paramount, reinforced silicone hoses are the right choice. They withstand the vacuum without collapsing and are also suitable for hygienic process handling. 
• Robust granule hoses: For more demanding tasks involving the conveyance of solid particles such as powders or granulates via negative pressure, granule hoses are designed to withstand prolonged wear and pulsating loads. Both standard granule hoses and antistatic granule hoses are suitable for this purpose. They are robust and can withstand the constant friction and pressure from powders and granules.

Whichever hose type you choose from our range, all materials in direct contact with the medium must, of course, comply with relevant regulations such as FDA CFR 21-177.2600, EC 1935/2004 and EC 2023/2006. 

A secure connection in your process line requires the right couplings. Dairy fittings are a classic choice for many types of liquids in your vacuum applications. They are easy to clean and ensure a stable and hygienic connection.  

In more demanding vacuum systems, where you work with very low pressure and long transport distances, dedicated vacuum fittings are required. They ensure tightness under high vacuum, reduce the risk of micro-leaks and support product safety during operation. 

Vacuum is a complex topic that requires an understanding of both the physics behind pressure and temperature conditions, and knowledge of how materials behave under vacuum conditions. Understanding the vacuum itself is only half the journey – the other half is about choosing the equipment that keeps your system leak-free and reliable.  

Do you need advice right now? Our specialists are ready to help you select the correct equipment for your specific vacuum applications. Call us on +45 7020 0422 or send an email to inquiry@alfotech.eu.  

We have given a short overview of the dedicated vacuum fittings, but next time we’ll go a step further. We’ll focus on their construction and how you can use them in practice. 

With vacuum technology, you can reduce oxygen content, lower operating temperatures and achieve gentler product handling. This results in longer shelf life, better taste, fewer breakdowns and energy-optimised processes. In practice, this means that you both protect product quality and improve operations. 

Yes, but this requires the system to be designed for it. Hoses and fittings must withstand both the cleaning agents and the temperatures used in the CIP system. The choice of materials must therefore be assessed based on both the vacuum level and the cleaning chemicals. A classic mistake is to choose components that are suitable for vacuum but not sufficiently chemical-resistant for the CIP agents you are working with. 

If you use standard pressure hoses without spiral reinforcement in a vacuum system, the hoses may collapse under the constant atmospheric overpressure from outside. This can completely block the flow and halt your production, whilst also creating additional resistance. Collapsed or deformed hoses are also difficult to clean, which increases the risk of contamination. It's therefore crucial that you choose a hose with a spiral that can keep the cross-section open. 

Start by assessing what pressure level you really need, what medium you are working with, and how demanding the temperature and hygiene requirements are in the process. Take a close look at whether your current equipment – hoses and fittings – can withstand negative pressure, or whether you need to switch to vacuum-compatible components.