SWEP B50

No. They share the 525 x 243 mm outline and both use 316-grade stainless plates with copper braze, which is why they get confused, but they are separate models with their own plates and part numbers. SWEP publishes a maximum flow of 104.35 GPM for the B45.

Do not accept one as a substitute for the other on the strength of the dimensions. Check the port centres on the old unit against the B50's 441 x 159 mm, read the model code, and note the connection size. If the nameplate says B50, the replacement is a B50 with the same plate letter and count. The B45 page has that model's own data.

It is used on industrial applications where high capacity is needed, and on steam-to-water and oil-to-water service.

Steam is where care is needed. The steam temperature has to sit inside the unit's rating and under the ceiling for copper braze, roughly 185 C. Condensate must drain freely: a unit that floods and clears repeatedly is cycled thermally and hammered, and the braze joints fatigue.

It is a poor fit for ammonia and for deionized water, both of which rule out copper braze, and for chloride-bearing water that calls for SMO 254.

The catalogued B50 part numbers on file run from 40 to 240 plates, in L, M and H plate types.

Count and plate letter work together. More plates give more surface and more paralell channels, so pressure drop falls and the approach tightens. The plate letter sets how hard each channel works: H for high heat transfer at high pressure drop, L for low pressure drop at lower heat transfer, M between. A viscous oil duty often lands on a lower-pressure-drop plate with more of them; a close-approach water duty goes the other way. For a new duty, send flows, temperatures and allowable pressure drop on both sides.

SC is 316/316L stainless plates with copper braze, the general-duty construction. It suits water, glycol mixes, steam and condensate within the rating, and mineral and hydraulic oils.

It does not suit ammonia, which attacks copper, or deionized and ultrapure water, which leach it. Chloride-bearing water - seawater, brackish or chlorinated cooling water - pits 316 and is a duty for SMO 254 plates. For process fluids outside that list, send the composition and temperature and we will confirm the material before quoting.

It is the pressure class. S is the category for a wide variety of applications, 31 bar at 155 C, and it is the class on the catalogued B50 part numbers on file, as in B50Mx60/1P-SC-S.

Treat it as a category, not as the rating of the unit in front of you. The stamped design pressure and temperature on the nameplate govern, and they are what an inspector or insurer will read. On steam duty in particular, check the steam pressure and its saturation temperature against the stamp before reusing a designation from an older installation.

Four things, in this order. The cover plate and port centre dimensions, to confirm the frame. The plate count, counted along the edge of the pack. The connection size and type at each port - the units on file have four 2 1/2 in connections. And any legible fragment of the designation, above all the letter between the model and the x.

That letter - L, M or H - cannot be recovered by measuring, and it changes the performance of the unit. If it is gone, send the duty the exchanger serves: fluids, flows, and inlet and outlet temperatures on both sides. We can work back to the plate type from that.

It can. The risk is not during operation but at shutdown. A steam-to-water unit that is isolated in an unheated plant room still holds condensate and water, and an oil cooler's water side sits full when the machine is off. Water freezing in the channels can split a brazed unit beyond repair.

Drain both sides for a winter shutdown, or run the water side on a glycol mix. If glycol is used, state the type and concentration with the duty: it raises pressure drop and reduces heat transfer, so the plate count has to be rated on the mix. See Freeze Protection.

These models are catalogued alongside the B50. Each has its own page with its dimensions, materials and part numbers.

SWEP B45 - Three-pass capable on the 525 x 243 mm frame.