Custom heat exchangers in the food industry

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Custom heat exchangers in the food industry One of the world's largest and most rapidly growing industries nowadays.

Case Study | Food industry | 05.2023

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Heat exchangers in the food industry In its broad sense, the food industry is one of the world's largest and most rapidly growing industries nowadays, primarily due to the direction in which the industry has been moving in recent years.

On the one hand, conscious nutrition is becoming a trend – consumers more often choose high-quality products from reliable sources. On the other hand, the growing demand for food products requires more efficient and cost-effective food processing. Both these facts have had a significant impact on the dynamic development in the area of food production and processing in recent years. It also applies – and perhaps above all – to food processing equipment, with no exceptions for heat exchangers.

The fulfillment of increasingly restrictive sanitary standards and guaranteeing the safety of food and consumption force the equipment manufacturers to strive not

only for continuous development and improvement of their products but also to look for new solutions. No wonder the food industry is one of the most demanding for heat exchanger manufacturers.

Heat – specifically the heat transfer process its efficiency and stability – plays a crucial role in every branch of the food industry, including dairy, food, beverage, brewery, etc. The effectiveness of this process affects not only the taste of a given product but, most of all, its nutritional value and, what is extremely important, its suitability for consumption.

One of the main goals of thermal food processing is to eliminate the hazardous organisms that may be found in many raw products, such as bacteria or parasites.

A poorly conducted heat treatment process may not only reduce the value of a given product by spoiling it but also threaten the health and life of consumers.

Case Study | Food industry | 05.2023

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Meeting market needs – AHE’s sanitary line

Being fully aware of the scope of our design and production capabilities, the client asked us to prepare a family of shell and tube heat exchangers for the broadly understood food industry, paying attention to the key aspects of this type of devices, such as: Choosing the most accurate solution is a complex process, often requiring extensive production knowledge supported by years of experience and the necessary technological and production capabilities.

Incorrectly adopted assumptions at the stage of analyzing the input parameters, designing and manufacturing the target device, may have a negative impact on the desired working process of the heat exchanger. The more sensitive the target process, the less forgiving any imperfections are. The food industry is an excellent example of this.

Therefore, choosing the right solution and its supplier is crucial to ensure the reliability and effectiveness of the process.

One of our long-term clients, who had been providing the food industry with solutions for many years, noticed how dynamically this market has been growing. Being fully aware of the requirements and challenges the market imposes on heat exchangers, he started searching for a reliable and high-quality solution that

would be capable of serving efficiently in diffrent branches of the food processing industry.

Through the years of our collaboration, we had been fortunate to work together on numerous successful projects for a variety of industries, which had helped us to build a mutual sense of trust and confidence.

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Superior construction materials – The heat exchanger to be made of high-quality stainless steel

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Reliability and robustness – ability to freely counteract thermal elongation

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Fouling resistance - product side to be designed to minimize deposition and retention of the medium

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Enhanced cleaning abilities – effortless draining, convenient Clean In Place

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Compactness – extensive heat exchange surface

Having a direct input of needs and expectations, we hit the ground running and started work on AHE's Sanitary Heat Exchangers Line.

Case Study | Food industry | 05.2023

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Case Study | Food industry | 05.2023

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From the well-proven solutions to the entirely new concept As usual, we started by verifying our shelf products in terms of their accuracy for the project or possible adaptation - implementing minor modifications to meet the requirements. Although we had a wide shelf-products portfolio at our disposal, most of the products fulfilled only 3 out of 5 requested featutes simultaneously. Their further modification turned out to be uneconomical or even technologically impossible. As there is no room for neither compromises nor half-measures in sanitary applications, we realized there was no other solution but to bring a totally new design from scratch.

cesses, such as sterilization or pasteurization, using high-temperature media as a heating medium, e.g., saturated steam.

It affects not only the life of the device but, above all, guarantees product safetyband prevents mixing of liquids due to microcracks.

The use of high-quality stainless steel and sealing material compliant with market and food regulations guarantees material compatibility and corrosion resistance for a wide range of products to be processed.

Having an outline of the basic concept of the device, we could move on to implementing subsequent features.

It all starts with a concept.

We knew that we first needed to find a mechanical concept of the heat exchanger, considering the materials and mechanical qualities around which, in further steps, we could develop all necessary sanitary features. This was where we started.

The idea based on the U-tube bundle (TEMA type BEU) allows for avoiding fractures and leakages caused by insufficiently compensated thermal expansion resulting from high-temperature differences between the product and utility side. This is essential in the context of devices used in food pro-

Case Study | Food industry | 05.2023

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First things first – no space for biological growth

Biological fouling is a common issue that almost the entire food industry has struggled with ever since the first commercial food processing lines started to operate.

Due to their properties - composition, consistency, or viscosity- many food products create ideal conditions for accumulating deposits on the heat exchange surface. Fouling, which largely concerns heat exchangers, generates millions of annual losses globally due to efficiency drops, maintenance actions, and product spoiling. No wonder such an aspect is a crucial technological challenge for manu-

factures of heat exchangers, who want to provide the market with reliable products.

Bearing in mind the above aspect, antifouling design became the starting point in turning shell and tube heat exchangers into a reliable sanitary devices.

Case Study | Food industry | 05.2023

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Crevice-free design with a smooth surface What makes crevice-free features so important in terms of food processing?

Considering the characteristics of food products, eliminating gaps, slots and threads on the product side is done primarily to prevent the formation of hardly accessible places , where the product may stagnate due to the limited and disturbed flow. This usually leads to the development of harmful microorganisms that can not only spoil the entire product in its entire volume but also, in extreme cases, cause real threats to the health and life of consumers. Therefore, from the view of the entire design, this aspect was the first to be solved on our list.

In addition to the gaps and crevices, the material's surface structure plays an essential role in the exchanger's susceptibility to biofouling. The lack of adequate roughness and homogeneity of the system significantly elevates the risk of sediment build-up. Besides the obvious sanitary hygienic reasons, this issue also has a key impact on the stability and economy of the entire food processing.

The sediment layer that may occur on the heat transfer surface has a negative effect, thus can reduce the efficiency of heat transfer and generate additional costs of frequent maintenance actions.

Our sanitary heat exchangers were featured with certain, wisely thought-out qualities to remedy this. The inner surface of the product side cover was polished to a roughness level of Ra 0.8 µm. Moreover, unlike our standard shell and tube products, we changed the form of the tubeto-tube sheet welded connection. To provide as smooth and homogeneous tube sheet surface as possible, the holes in the tube sheet were beveled, thus enabling the edges of the tubes to flush with the tube sheet surface. Like the cover, the tube sheet surface was polished to appropriate roughness.

To guarantee the accomplishment of requirements for the entire product side, bright annealed seamless pipes were used to produce U–tubing.

But how to manufacture a heat exchanger free of crevices and gaps?

Considering both the economic and functional aspects, we found the best solution to manufacture the product's side cover head. Instead of fabricating it by welding, we decided to use one piece of steel to be formed by CNC machining.

Such an approach enabled us to get a homogenous structure and eliminated the risk of discontinuity of welds, thus the presence of crevices and slots. Hand in hand with TriClamp sanitary connections, instead of threaded couplings, the product's side cover was free of gaps and cracks.

Case Study | Food industry | 05.2023

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Extended heat transfer area In addition to strictly sanitary requirements (main aspects related to the surface finish of the device), our client indicated that the design feature distinguishing the product should be the "market lead" heat transfer area. In general, considering shell and tube technology, this effect could be achieved by:

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Using more pipes or extending them

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Using pipes with a heat transfer area extended by corrugation, dimpling or forming a special formation.

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Using tube bundle with more tubes, which could be achieved by reducing their diameter.

Taking full advantage Turning the of our fabrication challenge into capability. an asset.

We instantly ruled out the first two approaches due to dimensional limitations imposed by our client (too large heat exchangers would not be competitive with these existing on the market) and the necessary sanitary requirements (homogeneous, smooth surface). Therefore, we focused on the third solution - delivering a compact package containing an increased number of pipes with a smaller diameter, of course not forgetting about maintaining critical sanitary aspects.

Due to the adopted design of the device based on the U-tube package, the technological challenge here seemed to be the minimum bending radius.

The combination of the full capabilities of our machining resources and the extensive experience of our engineers allowed us to bend the tubes with as much reduced bending radii as possible and maintain all crucial requirements for their geometry, strength, and, most importantly, the surface structure of the pipes at the bending side.

All of these allowed us to feature our sanitary heat exchangers with even up to 30% more heat transfer area than a competitive solution available on the market.

Case Study | Food industry | 05.2023

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Cleanability and full drainage.

Clean-in-place friendly solution.

There is no successful sanitary heat exchanger without well-developed selfcleaning abilities on its product side.

The message carried with this sentence was clear. We fully took advantage of what we had managed to work out so far in the project. Fabricating the product side cover by machining gave us practically unlimited freedom to adjust its geometry while maintaining the necessary strength.

The lack of gaps and slots, rounded internal edges, and the appropriate angular inclination with a smooth surface ensured no stagnant areas that could favor the product deposition. Thanks to this, a complete draining of the exchanger could take place, without a disassembly (Clean

In Place). It allowed for significant cost savings related to maintenance actions, and most importantly, it reduced losses of the valuable food product.

In addition, both the product side cover and the tube bundle were fully demountable. If necessary, it was possible to get full access to any area of the exchanger, which also significantly facilitated the mechanical cleaning process (Clean Out of Place)

Case Study | Food industry | 05.2023

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More than heat exchangers – product awareness provided by advanced numerical simulations With years of experience in the heat exchanger industry, we know that the device's reliable structure is only one of the many keys to success. There are no exceptions for sanitary exchangers. In case of heat exchangers for a wide range of applications, designed to work with various products and with different parameters, an equally important aspect is to assure the customer that the proposed device meets all the critical requirements, individual for a given product. In food processing, ensuring specific characteristics for a given medium, such as flow rates or local maximum and minimum temperatures through an entire heat exchanger, significantly impacts the efficiency and stability of the entire process.

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Using the full advantage of AIC's advanced computational capabilities As part of the sanitary devices design, we created a solution for each sanitary heat exchanger, based on advanced software for numerical analysis. The extensive software capabilities allowed us to simulate complex heat transfer processes for almost any food medium – from dairy products, beverages, and alcohol to vegetable and fruit preserves. As a result, every heat exchanger was supplied with an individual selection sheet representing the thermodynamic profile of the device for a given application. Thanks to this, the customer had a direct insight into the aspects important for the correctness and stability of the process while ensuring that he received exactly what he expected. Based on our experience, building full product awareness is the key to a fruitfull and long-term cooperation.

Heat exchangers in the food industry Case study 05.2023 | Copyright © 2023 All Heat Exchangers

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