Technical information - Welded spiral heat exchangers

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

Inovasi SelfClean™ Alfa Laval menjadikan alat penukar panas model SpiralPro sebagai pilihan cerdas saat menangani fluida kotor, lumpur, emulsi, bubur, serat, atau cairan yang mengandung partikel. Karena fluida mengalir terus-menerus dalam satu saluran tunggal, gaya fluida bekerja melawan endapan apa pun, “mendorongnya” melalui saluran dan keluar dari ujung yang lain.

Bentuk ringkas model SpiralPro membuat satu alat penukar panas SpiralPro dapat menggantikan beberapa alat penukar panas shell dan tube besar. Selain mengurangi persyaratan pemeliharaan dan pembersihan, hal ini juga memberikan manfaat infrastruktur yang cukup besar. Jika unit perlu dibersihkan, penutup dapat dilepas dengan mudah untuk dicuci dengan jet hidro.

Aplikasi

• Likuid kotoran yang mengandung padatan, serat, liquor, bubur, dan lumpur
• Pemanasan awal likuid-ke-likuid, pemanasan, pendinginan, pertukaran, dan pemulihan panas

Alat penukar panas model SpiralPro juga dioptimalkan untuk tugas yang melibatkan pemanasan uap likuid yang sangat kotor. Seperti semua unit SpiralPro, unit ini sepenuhnya dapat dibersihkan dengan cepat dan mudah menggunakan jet hidro.
Aliran arus balik juga memastikan pendekatan suhu yang sangat dekat untuk efisiensi termal maksimum.

Aplikasi

• Likuid kotoran yang mengandung padatan atau serat, cairan, bubur, dan lumpur serta fluida khusus lain yang memerlukan pemanasan dengan uap

Alat penukar panas model SpiralCond menawarkan solusi yang sangat efisien untuk pekerjaan dua fase yang sulit, termasuk kondensasi dan penguapan (reboiling). Desain ringkas SpiralCond dan rendah emisi karena dikonfigurasi secara vertikal, dibandingkan dengan alat penukar panas shell dan tube sejenis, serta mengurangi struktur pendukung dan kompleksitas perpipaan.

Unit SpiralCond memiliki aliran silang, bukan aliran berlawanan arah. Setiap unit sepenuhnya disesuaikan sesuai dengan pekerjaan yang diperlukan, dengan lebar saluran disesuaikan untuk memberikan penurunan tekanan terendah. Oleh karenanya, SpiralCond sangat ideal untuk aplikasi kondensasi vakum.

Aplikasi

• Gas: uap murni dan campuran dengan gas inert
• Uap/likuid: kondensor atas, kondensor refluks, kondensor vakum, kondensor ventilasi, reboiler dengan fluida kotoran, pendingin gas 

Untuk aplikasi kondensasi dan evaporasi yang melibatkan banyak media pendingin, Alfa Laval dapat menghadirkan model alat penukar panas SpiralCond yang terintegrasi dalam sebuah kolom. Seperti satu SpiralCond yang berdiri sendiri, konfigurasi ini memiliki aliran silang dan saluran terbuka untuk penurunan tekanan yang sangat rendah dalam situasi vakum.

Efisiensi tinggi SpiralCond memungkinkan kolom dibuat lebih pendek dengan diameter yang lebih kecil dibanding solusi kolom tradisional, sehingga biaya infrastruktur dan pemasangan jauh lebih hemat.

Aplikasi

• Uap-likuid: kondensor atas, kondensor refluks, kondensor vakum, dan kondensor ventilasi

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.