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Industrial semi-welded line

Alfa Laval Industrial semi-welded line is used when gaskets are not suitable for one of the process media. Also, the semi-welded line can take a higher design pressure compared to fully gasketed plate-and-frame heat exchangers.

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Unique sealing system

Alfa Laval Industrial semi-welded line handles most refrigerants and is particularly suitable for applications involving ammonia. Semi-welded heat exchangers are used in both organic and inorganic chemical processing when the chemicals involved limit the selection of gaskets that can be used or when the required design pressure makes fully gasketed plate-and-frame heat exchangers insufficient.

The media passes through the welded channel facing the ring gasket sealing between the laser welded cassettes. Alfa Laval semi-welded heat exchangers employ the Alfa Laval RefTight™, a unique sealing system  which guarantees high performance by positioning the laser weld on the outside of the ring gasket groove. The smooth ring gasket grove ensures equal sealing force over the entire porthole gasket.

Equipped with well-designed features, Alfa Laval Industrial semi-welded line of heat exchangers are easy to maintain and have a long service life. Some of the features available include:

  • ClipGrip™ gasket – a glue free gasket with superior alignment that ensures a perfect seal and trouble-free maintenance. 
  • Alfa Laval RefTight™ – a unique gasket groove design with maximum gasket support and minimum gasket contact.
  • CurveFlow™  distribution area  ensures full use of the heat transfer area and minimizes fouling.

Peace of mind

Alfa Laval global service network is never far away. 

How it works

The heat transfer area of a gasketed plate-and-frame heat exchanger consists of a series of corrugated plates, assembled between the frame and pressure plates, which retain the design pressure. For the highest thermal performance and to enable a very close temperature approach, fluids normally run counter-currently through the heat exchanger.

The sealing between the plates on the Industrial semi-welded line alternates between laser welds and gaskets. The laser welded channel allows use of fluids that are not compatible with normal gaskets and also allows for higher design pressure than fully gasketed plate-and-frame heat exchangers. Additionally, the Alfa Laval RefTight™ sealing system guarantees equal sealing force over the entire porthole gasket.

Industrial semi-welded line is available with various pressing depths and angles of the chevron pattern and various shapes of the corrugation which are carefully designed and selected to achieve optimal performance. The CurveFlow™ and the chocolate pattern distribution area are two design features available that ensure fluids are evenly distributed across the entire plate.  The result is that the entire heat transfer surface is fully utilized and stagnant zones that can result in fouling are avoided.

High flow turbulence between plates results in higher heat transfer; however, the consequence is pressure drop. Our thermal design engineers will help you design and select the model and configuration that is suitable for your application needs while delivering maximum thermal performance and minimizing pressure drop.

The Industrial semi-welded line can be configured in many ways. The animation shows single pass configuration of a fully gasketed plate-and-frame heat exchanger. The flow principle of a semi-welded heat exchanger is the same. The difference is that every second channel is sealed with a laser weld instead of a gasket. Multi pass with 2 or more passes on each side is also possible.

Product in focus: Alfa Laval TK20

The new Alfa Laval TK20 semi-welded gasketed plate heat exchanger is optimized to deliver the best in performance and reliability for heating and cooling of aggressive media. With its compact and leakage-proof design, flexible configuration and high serviceability, it is the optimal solution for applications where high efficiency is key. 




High energy efficiency 

With its new innovative plate design, the Alfa Laval TK20 provides superior flow distribution across the entire plate surface. Compared to a traditional plate design, the TK20 also maintains a low-pressure drop in the distribution area while enabling high-pressure drop for heat transfer. This results in improved heat transfer and higher energy efficiency thanks to the elimination of stagnant zones and reduced risk of fouling.

Compact size
Thanks to compact design combined with new plate design and big port connections, Alfa Laval TK20 is optimized for high capacity installations in small spaces.

Complete range
Alfa Laval offers a complete range of semi-welded gasketed plate heat exchangers for today’s demands in the refrigeration industry: Energy efficiency, lower approach (i.e. higher evaporating temperature) and operation with low delta temperatures/high flows.

Easy and safe maintenance
A new gasket design provides easy and cost effective maintenance. The frame is equipped with features that support the unit and secure safe opening and closing during service.  


Alfa Laval RefTight™

With the unique sealing system Alfa Laval RefTight™ for semi-welded gasketed plate heat exchangers the weld is positioned separately outside the ring formed gasket groove area. The separate ring formed gasket groove ensures equal sealing force over the whole port hole gasket. That guarantees high performance through the welded channel. The sealing properties are further improved by a fully supported ring gasket groove.

Key benefits
– Enhanced performance in high pressure and high temperature applications.
– High performance over the welded channel.
– Extended gasket lifetime.

Alfa Laval CurveFlow™ distribution area
The new design of the distribution area in TK20 means superior flow distribution and more usage of the main heat transfer area. This results in a number of benefits for the different applications:
– Increased energy efficiency gives more kW per m² plate surface.
– A more compact heat exchanger while fewer plates needed.
– Better flow distribution reduces the risk of fouling build up.
– Reduced maintenance costs – fewer plates mean faster cleaning and lower cost for spares.

Alfa Laval ClipGrip™ gaskets
Glue-free gaskets for fast and completely glue-free mounting thanks to new Alfa Laval ClipGrip™. Based on the innovative fastening design, gaskets stay in place during maintenance while reducing consumption of spare parts and additional time for re-gasketing.

Part of a broad range of gasketed plate heat exchangers

Industrial line is an extremely versatile range of heat exchangers for use in all types of industries. 

WideGap is a heat exchanger used for applications involving fibrous liquids, highly viscous fluids, and fluids containing coarse particles.

AlfaVap is a tailor-made, rising film plate surface evaporator.

AlfaCond is a compact, plate surface vacuum condenser.

Diabon® is a graphite plate-and-frame heat exchanger used for tough corrosive media.

AlfaQ™ is an AHRI certified gasketed plate-and-frame heat exchanger.

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