Sondex Heat Exchangers

Sondex is a Danish manufacturer of gasketed plate heat exchangers, acquired by Danfoss in 2016 and today operating as the SONDEX® standard plate heat exchanger brand within Danfoss's heat transfer portfolio. Sondex plate heat exchangers are widely used across HVAC, district heating and cooling, marine and offshore, dairy/food/beverage, chemical, and general industrial applications, and remain one of the most common gasketed PHE brands in service worldwide. SRJ is a Sondex Plate Heat Exchanger Manufacturer of compatible replacement parts - we produce Sondex replacement plates and Sondex gaskets engineered to match the original port layout, plate corrugation, and clamping dimension, so units already installed in your plant can be re-plated and re-gasketed without any change to the existing frame.

Our Sondex compatible plates and gaskets cover the full S-series range, available in AISI 304, AISI 316/316L, Titanium, Titanium-Palladium, SMO254, and Hastelloy (C276) plate materials, with gaskets supplied in EPDM, HEPDM, NBR, HNBR, and Viton (FKM). As a dependable source of Sondex Plate Heat Exchanger Parts, every plate and gasket we manufacture is dimensionally checked and pressure-tested before dispatch, giving plant engineers and procurement teams a reliable, drop-in alternative to long OEM/Danfoss lead times.

SRJ manufactures Sondex replacement plates and Sondex compatible gaskets pressed on tooling matched to original port position, plate corrugation, and gasket groove profile across the full Sondex S-series range - from compact S4A/S7A-class units up to large S100/S200-class frames. Because each plate reproduces the original clamping dimension and port layout, it seats correctly on the carrying and guiding bars of your existing frame, held between the stationary head and movable follower by the original tie bolts, without requiring any modification to the frame or tightening arrangement.

A distinctive feature of genuine Sondex plate design is its "chocolate island" flow-distribution groove at the plate's corner-hole outlet, which balances flow resistance across each channel so that fluid distributes evenly across the full plate width - even on wider plates - rather than relying on a simple linear guide groove that only distributes fluid on one side. This same-side diagonal flow design also allows the distribution zone itself to participate in heat transfer, effectively increasing usable heat transfer area compared to older side-flow plate designs. As a Sondex Plate Heat Exchanger Manufacturer of compatible parts, SRJ reproduces this chocolate-island guide geometry precisely in its tooling, so a replacement plate does not compromise the flow uniformity or thermal efficiency the original Sondex plate was engineered to deliver.

Sondex also offers plates in matched "twin" pairs of identical outer dimensions but different corrugation (channel) depth - for example, the S41 and S42 models share the same footprint and port sizing, but the S41 provides a narrower flow channel while the S42 provides a wider channel suited to fibrous, particulate, or high-viscosity media. SRJ manufactures both narrow-gap and wide-gap variants to this same twin-plate logic, so your heat exchanger can be configured or rebuilt for the correct plate mix - soft (low-resistance) channels, hard (high-transfer) channels, or a mixed arrangement - exactly as the original Sondex design intended.

Gasket fixing on Sondex units varies by plate generation and includes glued, clip-on, stud-type, and adhesive-free "SonderSnap"-style systems; SRJ manufactures Sondex compatible gaskets to match whichever fixing method your existing plates use, in EPDM, HEPDM, NBR, HNBR, and Viton (FKM), selected according to your process fluid, temperature, and pressure. Plate materials mirror Sondex's own standard offering - AISI 304/316 for general duty, Titanium and Titanium-Palladium for higher corrosion resistance, and SMO254 or Hastelloy (C276) for the most aggressive or high-chloride process media - in standard thicknesses of 0.5mm, 0.6mm, and 0.7mm.

SRJ's in-house Noida facility allows Sondex replacement plates and gaskets to be manufactured to order, supporting both current Danfoss SONDEX-branded units and older, independently-branded Sondex installations where genuine Danish/Danfoss OEM spares can mean lengthy import lead times. Every production batch is backed by our ISO 9001:2015 certified quality process - dimensional and flatness checks on plates, groove-fit verification on gaskets, and pressure testing of assembled plate packs on request - giving your procurement team a documented basis for approving non-OEM Sondex compatible plates and gaskets.

Don't see your exact model listed? Send us your Sondex nameplate details or an existing plate sample - we manufacture Sondex compatible plates and gaskets to your specific unit's dimensions, including older or discontinued Sondex models.