“Welded plate heat exchanger” describes more than one construction. A fully welded pack, a welded block with removable panels and a semi-welded cassette arrangement have different sealing and service characteristics. Identify the actual construction before comparing it with a gasketed frame.
Follow the seals along each fluid path
Welding can reduce reliance on elastomer channel seals for demanding service, but it does not mean every offered assembly is gasket-free. Covers, connections or the alternate circuit may still use seals.
Specify both fluids, chemistry, temperature, pressure and operating cycles. Material selection must cover plates, welds and any remaining seals. A higher nominal pressure rating does not establish compatibility with thermal cycling or a particular corrosive fluid.
Ask what can actually be cleaned
Some constructions expose channels when panels are removed; others depend on chemical cleaning through connections. Establish which side is accessible and what tools or cleaning process are permitted.
Alfa Laval's welded plate-and-block range illustrates one architecture with its own service provisions. Those provisions should not be attributed to every welded plate product.
Compare more than the initial heat-transfer area
Provide normal and peak duties, allowed pressure drop and fouling characteristics. Include startup, shutdown and cleaning conditions in the operating envelope. The selection should identify how performance will be maintained as the unit ages.
Reserve space for panel removal, lifting and service connections where required. For inaccessible welded packs, clarify repair feasibility and the consequences of a leak before choosing the unit for a critical process.
A complete quotation identifies the channel construction, materials, seals, design limits, thermal calculation and cleaning method. It should not rely on the word “welded” as a universal performance advantage.
Send the process conditions and maintenance constraints to shengtongJH for a welded-exchanger configuration matched to the duty.