A heat exchanger is a piece of equipment that continuously transfers thermal energy from one fluid to another without allowing the two media to mix. Alfa Laval heat exchangers achieve this through a package of corrugated metal plates, where each plate is separated from the next by a gasket or a brazed joint, creating alternating channels through which the hot and cold fluids flow in counter-current. The corrugated surface geometry generates high turbulence at relatively low flow velocities, which gives plate-type designs a higher overall heat transfer coefficient than conventional shell-and-tube equipment of equivalent footprint.

The Alfa Laval range covers five distinct construction categories — gasketed, brazed, fusion-bonded, scraped-surface, and tubular. Per Alfa Laval's published product documentation, the range spans flow rates from 0.18 m³/h to 5,000 m³/h and heat transfer areas from under 1 m² to 3,000 m². That breadth means a single supplier relationship can cover utility heating, hygienic pasteurisation, refrigerant condensation, viscous product processing, and high-purity biopharmaceutical duties. Plate materials include Alloy 304, Alloy 316/316L, Alloy 254, titanium, and nickel alloys, selected on the basis of chloride content, temperature, and process media. Gasket materials range from nitrile rubber for general-purpose and oil duties through EPDM for elevated temperatures and food applications.

Because the plate pack in a gasketed unit can be opened without specialist tools, inspection and mechanical cleaning are straightforward — an advantage that reduces planned downtime compared with sealed alternatives. Where continuous operation is required, Cleaning-In-Place (CIP) removes fouling deposits without opening the unit at all. The Alfa Laval range is distributed in Europe by Euroflow GmbH, covering industrial, hygienic, and HVAC applications across the full portfolio.

The five construction categories in the Alfa Laval portfolio address different combinations of pressure rating, cleanability, media aggressiveness, and viscosity. Selecting the correct type before specifying plate geometry or gasket material avoids costly late-stage redesign.

Gasketed plate heat exchangers

Gasketed units are the most widely used type in the Alfa Laval portfolio. The plate pack sits between a fixed frame plate and a moveable pressure plate, held together by tightening bolts. The frame plate is fixed, with portholes for piping connections; the pressure plate is moveable and compresses the plate pack against the frame plate. A carrying bar supports the plate pack from above, while a guiding bar keeps the lower ends of the plates aligned. Opening the pack for inspection or manual cleaning requires no special tooling beyond a torque wrench.

Gaskets are available in several attachment systems. ClipGrip™ and Clip-on designs are entirely glue-free and can be replaced with the plates still on the carrying bar, which reduces regasketing time significantly in food and dairy environments. Clip-ad and Base-ad systems use double-sided tape for fastening where clip attachment is not available for a given plate geometry. Gasket materials include nitrile rubber for general-purpose and oil-resistant duties, EPDM for elevated temperatures and food applications, and HeatSealF™ for steam heating duties.

Within the gasketed category, Alfa Laval offers industrial frames such as the T-series and hygienic frames including the FrontLine, BaseLine, and M-series. FrontLine frames can be supplied in stainless steel or silver-coated versions for the most demanding hygienic applications, including dairy pasteurisation and UHT treatment. BaseLine frames handle pressures up to 10 bar (g) and suit lower-flow pasteurisation and CIP heating duties. The M-series covers general heating and cooling in hygienic service where an epoxy-painted frame is acceptable, while the TS6-M series is thermally optimised for steam condensation duties. Multi-section configurations are possible through connection plates, which divide the plate pack into sections and allow two or more heat transfer processes within a single frame.

Brazed and fusion-bonded heat exchangers

Brazed plate heat exchangers are permanently sealed. The stainless steel plates are bonded with copper brazing material into a compact package with no gaskets. Per Alfa Laval's product documentation, this construction handles pressures up to 50 bar and temperatures from -196 °C to +550 °C, making brazed units well suited to refrigeration circuits and steam condensation duties where opening the unit is not required. Because a brazed unit cannot be mechanically cleaned internally, CIP or unit replacement is the only remediation path when fouling occurs.

AlfaNova fusion-bonded heat exchangers use AlfaFusion technology to bond 100% stainless steel plates without copper. The copper-free construction is relevant in applications where copper contamination would be a process or regulatory concern — certain food and biopharmaceutical duties in particular. Like brazed units, AlfaNova is a sealed construction and cannot be opened, but the all-stainless build provides superior corrosion resistance compared with copper-brazed alternatives.

Scraped-surface and tubular heat exchangers

For fluids that plate geometry cannot handle — high-viscosity products, sticky materials, products with large particulates, or those that crystallise on heat transfer surfaces — the Contherm scraped-surface heat exchanger uses rotating scraper blades to continuously clear deposits. It is widely used in food and personal care for products with low to extremely high viscosities. The ViscoLine tubular range handles low to medium viscosity products containing particulates and is used in food and beverage for pasteurisation, UHT treatment, and heat regeneration. At the high end of hygiene requirements, the Pharma-X tube-in-tube design and PharmaLine double-tube-sheet shell-and-tube unit serve biopharmaceutical applications requiring full drainability and protection against cross-contamination.

The Alfa Laval heat exchanger portfolio maps across six major industry segments that Euroflow serves. Each segment places distinct demands on plate material, gasket chemistry, cleanability, and pressure rating. The table below captures the primary pairing of industry, process duty, and heat exchanger type; the sections that follow explain the engineering rationale behind each selection.

Dairy and food processing

Pasteurisation and UHT treatment require heat exchangers that can sustain precise temperature profiles, tolerate thermal cycling, and be fully cleaned between product runs. Gasketed FrontLine units with Clip plates handle dairy pasteurisation and yoghurt cooling; the glueless Clip-on gaskets simplify gasket replacement and reduce the risk of contamination from adhesive residues. For products with fibres or particulates — fruit juices, prepared soups, sauces — WideStream Clip plates reduce the number of contact points per unit area, which limits blockage and extends uninterrupted run times. Where viscosity is too high for a plate design, ViscoLine tubular heat exchangers handle gentle heating and cooling without product degradation.

Brewing and beverage

Wort cooling after the kettle is one of the highest heat-load duties in a brewery — the heat exchanger must drop wort temperature rapidly, often from above 90 °C to pitching temperature, while handling significant levels of protein and hop debris. Gasketed industrial units with appropriate chevron-angle plates handle this duty, and the openable plate pack allows thorough manual cleaning between brews. Beer pasteurisation and flash pasteurisation of juices operate in the hygienic range, where the same CIP-compatible frame designs used in dairy apply. Plate material selection follows the chloride content of the cooling water: Alloy 316/316L covers most municipal water supplies, while titanium is specified for brackish or coastal water sources.

Pharmaceutical and biopharmaceutical

In pharmaceutical manufacturing, preventing cross-contamination between product and service media is a regulatory requirement. The PharmaLine double-tube-sheet design addresses this by providing a physical gap between the two tube sheets; any leakage across either sheet drains away before it can reach the other media. For point-of-use cooling on Water For Injection ring mains, the Pharma-X tube-in-tube design eliminates the risk of product contamination. AlfaNova fusion-bonded units are frequently specified for CIP solution heating with steam where copper contamination from brazed units would be unacceptable. The alfa laval heat exchanger range for this sector is designed with documentation and validation support in mind, as comprehensive records are expected by regulatory authorities.

HVAC, district heating, and industrial cooling

HVAC and district heating applications are typically large-volume, low-fouling duties where gasketed industrial units operating on water-to-water duty represent the most economical solution. Plate material follows chloride content: at concentrations up to 25 ppm and temperatures up to 80 °C, Alloy 304 is acceptable; above 50 ppm chloride, Alloy 316/316L is required; brackish and sea water demands titanium. Industrial oil cooling, hydraulic oil circuits, and quench oil systems specify nitrile gaskets because of their resistance to oils, with plate materials selected for the service-side water chemistry. Plate heat exchangers can handle oils with viscosities up to 2,500 cP, and emulsions at concentrations below 5% can be treated hydraulically like water. For compact refrigeration circuits and steam heating in utilities, brazed plate heat exchangers provide high-pressure capability in a small footprint without the maintenance overhead of a gasketed design.

Operating principle and key components

A gasketed plate heat exchanger consists of a fixed frame plate, a moveable pressure plate, a carrying bar from which the plate pack hangs, a lower guiding bar that keeps the plates aligned, and a set of tightening bolts that compress the pack. The plate pack itself comprises end plates, channel plates, and — in multi-pass or multi-section configurations — additional plate types such as turning plates, partition plates, and connection plates. Each channel plate carries a gasket that seals two adjacent channels and directs one fluid into alternate channels. The gasket arrangement means the hot and cold media flow in counter-current through separate channels separated only by the plate wall.

Per Alfa Laval's published product data, plate walls are typically 0.3 mm to 0.6 mm thick stainless steel. This minimal wall thickness keeps conductive resistance low and is one reason why plate designs achieve higher overall heat transfer coefficients than shell-and-tube alternatives. The corrugated chevron pattern on each plate generates turbulence as fluid passes through the narrow channel, breaking down the boundary layer at the plate surface and increasing the convective coefficient on both sides.

Assembly, the A-measurement, and tightening procedure

Correct assembly of the plate pack is essential to sealing performance and gasket life. The A-measurement — defined in the Alfa Laval maintenance manual (document 200006684-8-EN-GB) as the distance from the inside face of the frame plate to the inside face of the pressure plate — is the single most important assembly parameter. Torque values in Alfa Laval's tightening tables define a maximum only; the A-measurement always takes precedence over torque readings, and tightening must stop once the A-measurement is reached regardless of the torque value recorded.

The closing procedure, as described in the same maintenance manual, involves tightening the tightening bolts crosswise in stages. Bolts are first tightened until the plate pack reaches 1.2 × A, at which point the gaskets are partially compressed and the pack can be heated with water at 30 °C to 40 °C to soften the gasket material before completing the tightening to the final A-measurement. Locking bolts are installed at a later stage, after the tightening bolts have been brought to the A-measurement. For hard gasket materials (such as EPDMAL, HNBRAL, and FKMAL), the tightening procedure is more critical: improper gasket compression can cause gasket crushing or plate deformation, and slow tightening at 3–4 rpm is recommended to allow gasket relaxation.

When a unit is taken out of service for an extended period, the Alfa Laval maintenance manual (200006684-8-EN-GB) recommends opening the plate pack to 1.25 × A and leaving the gaskets to relax for 24–48 hours before re-tightening. This restores gasket elasticity and reduces the risk of leakage on restart.

The self-cleaning effect and fouling

The same turbulence that drives high thermal efficiency also suppresses fouling. Turbulent flow continuously disturbs the fluid layer closest to the plate surface, reducing the rate at which deposits can accumulate. Per Alfa Laval's heat transfer documentation, a plate heat exchanger operating in water-to-water service can achieve an overall k-value in the order of 8,000 W/m² °C under favourable conditions, against a typical figure below 2,500 W/m² °C for a shell-and-tube design.

The higher k-value has a direct consequence for how fouling allowance should be specified. Alfa Laval's published guidance notes that a typical k-value for a plate heat exchanger is 6,000–7,500 W/m² °C, while a shell-and-tube exchanger typically achieves 2,000–2,500 W/m² °C. A fouling factor (Rf) of 1 × 10⁻⁴ m² °C/W applied to the shell-and-tube range produces a design margin of 20–25%. To achieve the same 20–25% margin in a plate design, Alfa Laval's documentation indicates that an Rf of only 0.33 × 10⁻⁴ m² °C/W is required. Oversizing to compensate for fouling adds parallel channels, lowers flow velocity per channel, and can actually increase fouling risk — a design margin of 0–15% depending on water quality is generally sufficient for plate-type equipment in water service.

When CIP is not sufficient to remove deposits, the gasketed plate pack can be opened and the plates cleaned manually. Alfa Laval's maintenance manual specifies that hydrochloric acid must not be used with stainless steel plates, and that cleaning water must not exceed 330 ppm chloride ions. Aluminium carrying bars and support columns require protection from cleaning chemicals during manual cleaning.

Selecting the right heat exchanger

Six parameters define the thermal problem before plate selection begins: the heat load, the inlet and outlet temperatures on both sides, the maximum allowable pressure drop on each side, the maximum operating temperature, the maximum operating pressure, and the flow rates. Once these are established, the selection follows a logical sequence.

Thermal length (Θ) describes how demanding a duty is from a heat transfer perspective. It is calculated as the temperature change on one side divided by the log mean temperature difference. Per Alfa Laval's heat transfer documentation, plate heat exchangers can achieve Θ values of 10 or higher, while shell-and-tube designs are practically limited to Θ ≈ 1 without putting multiple units in series. This makes plate designs the preferred choice for close-approach duties such as heat recovery, free cooling, and process-to-process heat exchange where the temperature difference between the two streams is small.

Plate geometry and pressing patterns

Most Alfa Laval plates are available in two chevron angles. A low chevron angle (type 1) produces a longer thermal channel with a higher pressure drop and better heat transfer — suited to duties with a large Θ and a generous pressure drop allowance. A high chevron angle (type 2) gives a shorter thermal channel with lower pressure drop, suitable when pumping energy is constrained. Mixing plates of different chevron angles within one pack creates an intermediate duty point, a common configuration for optimising a specific thermal and hydraulic specification. Asymmetric plates — where the two sides of the plate hold different fluid volumes — extend optimisation further when the two media have substantially different flow rates or thermal capacities.

Plate heat exchangers versus shell-and-tube alternatives

The two types serve overlapping but not identical ranges. Plate designs offer a smaller footprint, higher k-values, and easier access for cleaning and regasketing. Shell-and-tube units tolerate higher working pressures in large diameters, handle slurries and aggressive media that would damage thin plate material, and are the established choice where local pressure vessel codes mandate tube-bundle construction. For the majority of water, aqueous solution, food, and HVAC duties within the pressure envelope that gasketed and brazed plate designs cover, the plate heat exchanger delivers more heat transfer area per unit of floor space and a lower fouling factor requirement — both of which translate directly to lower capital cost and lower operating cost over the service life of the equipment.