SWEP B35T

Weight follows the published formula of 8.52 kg plus 0.256 kg per plate (18.77 lb plus 0.564 lb per plate). A 20-plate unit is about 13.6 kg (30 lb); a 160-plate unit, the largest count on file, is about 49.5 kg (109 lb); a full 260-plate pack reaches about 75 kg (165 lb), before the water inside it.

None of that belongs on the connections. Stand larger units on a base bracket or shelf and strap the body back to the wall or frame, then bring the pipes to the ports with their own supports so the connections carry no load. See Mounting and Piping.

It is the pressure class. B35T part numbers on file come in two: S and M. S is the general-duty category, 31 bar at 155 C. M is the higher category, up to 45 bar at 135 C and fatigue tested, used where the unit sees refrigerant or cycling pressure.

These are categories, not the rating of a particular unit - the stamped figures on the nameplate govern. The mistake to avoid is replacing an M unit with an S unit because the plate count and connections match. It will fit, and it will be under-rated for the system.

Because it sets how much fluid the unit holds and how fast it responds. SWEP publishes the same per-channel volume for both sides of the B35T; total hold-up per side is that figure times the number of channels on that side, about half the plate count.

On district heating and tap water duty a small hold-up means the outlet temperature tracks the control valve closely. On oil cooling it tells you how much oil the cooler adds to the system fill. And when a unit is drained for freeze protection or flushed during cleaning, it is the volume you are moving, so it sizes the cleaning tank and pump.

Mount it upright with the ports horizontal, and pipe the two circuits counter-current - hot in at one end, cold in at the other. Counter-current flow gives the closest approach; piped co-current by mistake, the same unit falls well short of its rated duty, and nothing looks wrong untill the temperatures are logged.

On the B35T the wide plate and large ports invite heavy pipework. Support it independently, allow for expansion on long heating runs, and keep water hammer and pump pulsation off the unit, because they fatigue the braze joints. Fit a strainer upstream on any open or dirty circuit.

In place. A brazed unit cannot be opened, so the fouled side is isolated and a cleaning solution is circulated through it, ideally against the normal flow direction and faster than the duty flow, followed by a full rinse.

The solution has to be safe for both 316/316L and copper braze, which rules out strong acids left in for long periods. Rising pressure drop with falling outlet temperature points to fouling; falling pressure drop with mixing of the two circuits points to a leak, and cleaning will not help that. If cleaning becomes frequent, the cause is usually a missing strainer or low channel velocity from an oversized unit. Details are in Cleaning in Place.

These models are catalogued alongside the B35T. Each has its own page with its dimensions, materials and part numbers.

SWEP B35 - Cross-flow dual configurations on a 393 mm plate.