industrial semi welded line

Alfa Laval Industrial Semi-Welded Plate Heat Exchangers

Alfa Laval industrial semi-welded plate heat exchangers combine efficient plate heat-transfer technology with a reduced gasketed sealing area on the demanding-media side.

They are designed for industrial heating, cooling, evaporation and condensation duties involving refrigerants, aggressive media or applications where a conventional gasketed plate heat exchanger may not be the preferred option.

Surya Sankara Trading Pvt. Ltd. supports industrial customers in Hyderabad, Telangana and other South Indian locations with Alfa Laval semi-welded heat exchanger enquiries and application discussions.

Surya Sankara Trading Pvt. Ltd. is an Authorised Distributor for Alfa Laval products.

What Is a Semi-Welded Plate Heat Exchanger?

A semi-welded plate heat exchanger consists of pairs of heat-transfer plates welded together to form cassettes. The welded channel carries one medium, while conventional gaskets seal the channels between adjacent cassettes.

This construction reduces the extent to which the demanding fluid comes into contact with elastomeric gaskets while maintaining the serviceability and configuration flexibility associated with a plate-and-frame heat exchanger.

A semi-welded heat exchanger is not completely gasket-free. Gaskets remain between the welded cassettes and around applicable port areas.

How Does a Semi-Welded Heat Exchanger Work?

Hot and cold fluids pass through alternating channels without mixing under normal operating conditions. Heat moves across the thin metal plates from the warmer medium to the colder medium.

In many applications:

• A refrigerant or aggressive medium flows through the welded channels

• Water, brine, glycol or another compatible utility flows through the gasketed channels

• The plate pattern promotes turbulence and efficient heat transfer

• The frame holds the cassette pack at the specified compression

• Connections direct the fluids through their respective circuits

Counter-current flow can support efficient heat recovery and close temperature approaches where the process conditions permit.

Benefits of the Industrial Semi-Welded Line

Reduced Gasket Exposure

Welding plate pairs reduces direct gasket exposure to the medium flowing through the welded channel. This can be useful for refrigerants and selected aggressive fluids.

Compact Heat-Transfer Surface

The corrugated plate design provides substantial heat-transfer area within a compact footprint. This may reduce installation-space requirements compared with certain conventional exchanger designs.

Efficient Heating and Cooling

Thin plates and turbulent flow can support efficient heat transfer and close temperature approaches, depending on the selected plate pattern and process conditions.

Serviceable Plate-and-Frame Construction

The cassette pack can be accessed after the unit is safely isolated, depressurised, drained and opened according to the manufacturer’s instructions.

Flexible Capacity and Configuration

Depending on the model and available frame capacity, the number of cassettes and flow arrangement may be configured for the required thermal duty.

Suitable for Evaporation and Condensation

Semi-welded plate heat exchangers may be configured for selected refrigerant evaporation and condensation duties.

Controlled Fluid Distribution

Appropriate plate and distribution-area design helps spread the medium across the heat-transfer surface. Good distribution is important for thermal performance, fouling control and reliable operation.

Industrial Refrigeration Applications

Semi-welded plate heat exchangers are widely considered for industrial refrigeration duties involving ammonia and other compatible refrigerants.

Potential duties include:

• Refrigerant evaporation

• Refrigerant condensation

• Liquid cooling

• Glycol cooling

• Brine cooling

• Heat recovery

• Oil cooling

• Process-water cooling

• Secondary refrigeration systems

• Heat-pump applications

The selected unit must meet the refrigerant, pressure, temperature, capacity and safety requirements of the installation.

Ammonia Plate Heat Exchangers

Ammonia refrigeration systems require equipment selected for the refrigerant’s operating pressures, temperatures and material-compatibility requirements.

A semi-welded arrangement can place ammonia inside the welded cassette channels while the secondary medium flows through the gasketed channels. This reduces the number of conventional gasketed sealing points exposed to the refrigerant.

Selection requires information such as:

• Refrigeration capacity

• Evaporating or condensing temperature

• Ammonia circulation arrangement

• Inlet vapour quality, where applicable

• Pressure and temperature limits

• Secondary-fluid temperatures

• Allowable pressure drop

• Oil content

• Required superheat or subcooling

• Applicable refrigeration standards

Ammonia refrigeration equipment must be designed, installed and serviced by appropriately qualified personnel.

Heating and Cooling Aggressive Media

Industrial semi-welded plate heat exchangers may also be evaluated for selected chemical and process duties involving media that require reduced gasket exposure.

Suitability depends on:

• Complete chemical composition

• Concentration

• Temperature

• Pressure

• Possible contaminants

• Plate-material compatibility

• Weld compatibility

• Gasket compatibility

• Corrosion allowance requirements

• Cleaning procedure

No material should be recommended solely from a general chemical-resistance table. Actual operating conditions must be reviewed.

Semi-Welded Versus Gasketed Plate Heat Exchangers

A conventional gasketed plate heat exchanger uses gaskets between every individual plate. This design provides high flexibility and convenient access to individual heat-transfer surfaces.

A semi-welded unit uses welded plate pairs or cassettes. One side of each cassette is welded, reducing gasket exposure to the fluid in that channel.

A semi-welded heat exchanger may be considered when:

• One medium is a refrigerant

• One fluid is difficult for conventional gasket materials

• Reduced gasket exposure is desirable

• Compact heat transfer is required

• Access to the cassette pack remains valuable

A fully gasketed unit may be preferable when both fluids are gasket-compatible and regular access to every individual plate is a priority.

Semi-Welded Versus Fully Welded Heat Exchangers

Fully welded heat exchangers eliminate the conventional gasketed plate pack and may be selected for more demanding temperature, pressure or hazardous-fluid duties.

Semi-welded technology retains a gasketed plate-and-frame structure between cassettes. It can therefore offer a balance between reduced gasket exposure and service accessibility.

The correct choice depends on:

• Process fluids

• Temperature and pressure

• Required access

• Cleaning method

• Leakage risk

• Thermal cycling

• Applicable construction codes

• Maintenance strategy

Information Required for Selection

Please provide the following information for an industrial semi-welded plate heat exchanger enquiry:

• Process and utility-fluid names

• Refrigerant type, where applicable

• Flow rates

• Inlet temperatures

• Required outlet temperatures

• Operating pressures

• Design pressures and temperatures

• Allowable pressure drop

• Fluid density and viscosity

• Concentration

• Solids or fibre content

• Fouling tendency

• Plate and gasket material restrictions

• Required thermal capacity

• Connection requirements

• Applicable design standards

• Plant location

Safety data sheets should be supplied for hazardous, corrosive or specialised fluids.

Plate and Gasket Material Selection

Plate material must be compatible with both the fluid and the joining method used to manufacture the welded cassette. Gasket material must be compatible with the media to which it is exposed.

Selection should consider:

• Continuous and peak temperature

• Fluid concentration

• Pressure

• Cleaning chemicals

• Operating duration

• Thermal cycling

• Oils and possible contaminants

• Ageing and permeation behaviour

Final material selection should be confirmed as part of the technical evaluation.

Maintenance Considerations

Semi-welded plate heat exchangers require maintenance appropriate to their construction and application.

Maintenance may include:

• Monitoring temperatures and pressure drop

• Inspecting for external leakage

• Reviewing refrigeration-system performance

• Checking plate-pack compression

• Cleaning the accessible cassette surfaces

• Inspecting cassette gaskets

• Checking frame and tightening bolts

• Confirming connection integrity

• Following the prescribed cleaning procedure

• Replacing compatible gaskets when required

Welded cassettes must not be treated as ordinary individual gasketed plates. Inspection, cleaning and replacement procedures should follow the manufacturer’s instructions.

Industries and Applications

Alfa Laval industrial semi-welded plate heat exchangers may be considered in:

• Cold-storage facilities

• Food and beverage processing

• Dairy plants

• Breweries

• Pharmaceutical manufacturing

• Chemical processing

• Petrochemical operations

• Edible-oil processing

• Ice-manufacturing plants

• Refrigeration compressor packages

• District cooling

• Heat-pump installations

• Process cooling systems

• Marine refrigeration

Application suitability must be established from actual process data.

Semi-Welded Plate Heat Exchangers in Hyderabad

Surya Sankara Trading supports industrial customers in Hyderabad, Telangana and other South Indian locations with preliminary selection discussions and product enquiries for Alfa Laval industrial semi-welded plate heat exchangers.

Customers can approach us regarding:

• New refrigeration installations

• Ammonia evaporator or condenser duties

• Existing heat exchanger replacement

• Glycol and brine cooling

• Refrigeration-system expansion

• Chemical heating or cooling

• Heat recovery

• Replacement cassette and gasket enquiries

• Plate heat exchanger service requirements

For a meaningful review, send the equipment duty, refrigerant or fluid details, temperatures, flow rates, pressures and plant location.

Why Contact Surya Sankara Trading?

• Authorised Distributor for Alfa Laval products

• Application-focused enquiry coordination

• Hyderabad-based industrial contact point

• Support for refrigeration and process applications

• Assistance with process-data collection

• Spare-parts and service enquiries

• Support across Telangana and South India

Frequently Asked Questions

What is a semi-welded plate heat exchanger?

It is a plate-and-frame heat exchanger constructed using welded pairs of plates called cassettes. One channel is welded, while gaskets seal the channels between adjacent cassettes.

Is a semi-welded plate heat exchanger completely gasket-free?

No. The plates within each cassette are welded, but gaskets are still used between cassettes and around applicable sealing areas.

Why are semi-welded heat exchangers used for ammonia?

The refrigerant can flow through welded cassette channels, reducing its exposure to conventional interplate gaskets while retaining a serviceable plate-and-frame construction.

Can a semi-welded heat exchanger be used as an ammonia evaporator?

Yes, a correctly selected semi-welded heat exchanger may be used for ammonia evaporation. Refrigeration capacity, circulation, vapour quality, temperatures and pressures must be evaluated.

Can it also be used as a condenser?

Yes. Semi-welded units can be configured for selected condensation duties when designed for the refrigerant, thermal load and operating conditions.

What fluids can flow on the other side?

Depending on the application, the secondary side may contain water, glycol, brine or another compatible process fluid. Material and gasket compatibility must be confirmed.

What is the difference between semi-welded and gasketed plate heat exchangers?

A gasketed unit has gaskets between individual plates. A semi-welded unit uses welded plate pairs, reducing gasket exposure on one side.

What is the difference between semi-welded and fully welded heat exchangers?

A semi-welded unit retains gasketed joints between cassettes and can be opened for appropriate maintenance. A fully welded exchanger does not use a conventional gasketed plate pack.

Can semi-welded cassettes be cleaned?

Accessible cassette surfaces can be cleaned using an approved procedure compatible with the plates, welds and gaskets. The method depends on the deposit and equipment model.

Can capacity be increased by adding cassettes?

It may be possible for certain units if the frame, connections and thermal design permit it. A technical review is required before changing the plate pack.

How is the correct unit selected?

Selection requires fluid properties, refrigeration or thermal capacity, flow rates, temperatures, pressures, allowable pressure drop and material requirements.

Are semi-welded heat exchangers suitable for aggressive chemicals?

They may be suitable for selected chemical duties. Compatibility of the plates, welds and remaining gaskets must be assessed against the complete operating conditions.

Does Surya Sankara supply semi-welded plate heat exchangers in Hyderabad?

Surya Sankara Trading supports Alfa Laval semi-welded plate heat exchanger enquiries in Hyderabad, Telangana and other South Indian locations.

Is Surya Sankara Trading an Alfa Laval authorised distributor?

Yes. Surya Sankara Trading Pvt. Ltd. is an Authorised Distributor for Alfa Laval products.

Request a Semi-Welded Heat Exchanger Quote

Send your refrigeration or process data to Surya Sankara Trading for preliminary review.

Please include:

• Refrigerant or process-fluid name

• Required capacity

• Flow rates

• Inlet and outlet temperatures

• Operating and design pressures

• Allowable pressure drop

• Material restrictions

• Plant location

Mobile: +91 97042 70101
Email: suryasankaratraders@gmail.com
Location: Hyderabad, Telangana

 Request a Semi-Welded PHE Quote