How do spiral heat exchangers work

Alfa Laval spiral heat exchangers are circular units containing two concentric spiral flow channels, one for each fluid. The different media flow counter currently: one fluid enters the centre of the unit and flows towards the periphery, the other enters the unit at the periphery and moves towards the centre. The channels are curved and have a uniform cross section. There is no risk of intermixing.

The product channel is normally open on one side and closed on the other. The channel for the heating/cooling medium can sometimes be closed on both sides, depending on the cleanliness of the heating/cooling medium. Each channel has one connection in the centre and one on the periphery of the heat exchanger.

The single-channel geometry also creates a scrubbing effect that we refer to as the SelfClean™ design. If fouling does occur in the heat transfer channel, the cross-section of this part of the channel is decreased. However, since the entire flow must still pass through the channel, the velocity increases, the resulting fluid force then flushing away any accumulations of deposits as they form.

Compare this design with shell-and-tube heat exchangers where the flow enters different tubes in parallel. When tubes start to foul, pressure drop increases pushing the fluid to find alternative flow paths. The result is that fouling and clogging of the tubes happens very quickly. With Alfa Laval spirals, on the other hand, fouling and clogging is virtually eliminated.

Our welded spiral product range

阿法拉伐的 SelfClean? 構造使 SpiralPro 模型換熱器成為處理臟液、污泥、乳液、漿液、纖維或顆粒負載液體時的明智選擇。 由于流體在單個通道中連續流動，因此流體力可作用于任何沉積物，“推動”它們通過通道，并從另一端流出。

SpiralPro 模型的緊湊特性使得我們通常可使用一臺 SpiralPro 交換器來替換幾個大型管殼式換熱器。除了減少維護和清潔要求外，還可以帶來可觀的基礎設施優勢。 如果設備需要清潔，可以很容易地拆下蓋子，并用水力噴射器清洗。

應用

• 含有固體、纖維、液體、漿液和污泥的污垢液體
• 液體至液體的預熱、加熱、冷卻、互換和熱回收

還提供經過優化、可用來蒸汽加熱高度污染的液體的 SpiralPro 型號換熱器。 與所有 SpiralPro 裝置一樣，這些裝置完全可以通過液壓噴頭快速方便地清潔。
逆流流動還確保了非常小的溫差，以實現最大的熱效率。

應用

• 需要蒸汽加熱的含有固體或纖維、液體、漿液和污泥的污垢液體以及其他具有挑戰性的流體。

SpiralCond 模型換熱器為挑戰兩相任務提供了高效解決方案，包括冷凝和蒸發（再沸）。 與同等的管殼式換熱器相比，SpiralCond 的緊湊設計和垂直配置使其占地面積非常小，同時還減少了支撐結構和管道復雜性。

SpiralCond 裝置具有交叉流動，而非逆流流動。 每個單元都根據所需的負載完全定制，通道間距經過調整，可提供最低壓降。 因此，阿法拉換熱器SpiralCond 非常適合真空冷凝應用。

應用

• 氣體：純蒸氣和含有惰性氣體的混合物
• 蒸汽/液體：頂部冷凝器、回流冷凝器、真空冷凝器、排氣冷凝器、帶有污垢液的再沸器、氣體冷卻器 

對于涉及多種冷卻介質的冷凝和蒸發的應用，阿法拉伐可以提供集成在塔中的 SpiralCond 型號換熱器。 與單獨的獨立式阿法拉伐換熱器 SpiralCond 一樣，這種配置具有交叉流動和開放通道，可在真空情況下實現極低壓降。

與傳統塔式解決方案相比，高效率 SpiralCond 使塔的高度更短，直徑更小，從而大大節省了基礎設施和安裝成本。

應用

• 汽液：頂部冷凝器、回流冷凝器、真空冷凝器和通風冷凝器

Unique features of Alfa Laval Welded spiral heat exchangers

Superior cleaning and extended performance

The SelfClean design of Alfa Laval spirals provides a reliable solution for fouling and clogging in duties involving challenging fluids, sludges, emulsions, slurries, fibres or particle loaded liquids.

Each circuit on a spiral unit consists of a single flow channel. This continuously curving, single-channel geometry creates high turbulence to minimize fouling from the start. If fouling does start to occur, local velocity increases, since the entire flow must still pass through the channel. This creates a scrubbing effect that flushes away any accumulations of deposits as they form.

An additional benefit of this design is that it eliminates the risk of dead spots and stagnation for more efficient heat transfer.

Automated, reliable channel enclosure

The manufacturing of Alfa Laval’s spiral heat exchangers incorporates an automated process for bending the edge of the channels. This is followed by a cold-metal-transfer automatic welding machine for the final closure weld.

The combined effect of this so-called RollWeld technique is consistent quality of the channel closure. That, in turn, is critical for the strength and corrosion resistance of the channel welds and thus the reliability of the overall unit.

A custom solution for high-pressure duties

For customers whose processes demand higher design and differential pressures than traditional spiral heat exchangers can provide, Alfa Laval offers capabilities to fully tailor a unique solution to match their needs.

We design our HighP spiral heat exchangers using a range of features, including a double gasket system, a self-supporting internal coil, and a special body and shell with bolted cover. Our experienced engineers work with you throughout the design process to make sure you get the ideal heat exchanger for your specific challenges.

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