SWEP B320LT

Too small, and the unit runs at a high pressure drop with a wide approach: on a district heating substation the primary return comes back hotter than the network allows, and on an oil cooler the oil temperature creeps up under load.

Too large costs more and can work worse. With flow spread over too many channels, velocity drops, the fluid distributes unevenly along a deep plate pack, and fouling settles in the slow channels. On a frame this size the over-sizing is often deliberate - a margin on a margin. Size to the real peak duty with a stated fouling allowance instead.

The designation from the nameplate, such as B320LTHx120/1P-SC-S 4x2 1/2", or the SWEP article number. Every part of the string matters on this frame, starting with the model letters, because the B320HT has the same outline.

If the nameplate is unreadable, send the overall dimensions, the port centres, the plate count and the type and size of all four connections, along with the two fluids and what the unit does. A photo of the front cover and of the plate edges helps us confirm the count. We will confirm the configuration and its availability with the quote.

Multiply the published per-channel volume, which is the same on both sides of the B320LT, by the number of channels on each side - about half the plate count. On a 200-plate unit that is a meaningful quantity on each circuit.

It matters for three things. On an oil cooler it is extra oil in the system fill. On a glycol circuit it is part of the volume to be dosed to concentration. And for cleaning in place it sets the size of the cleaning tank and how much solution and rinse water you need. On heating duty it also affects response: more hold-up means the outlet reacts more slowly to the control valve.

The datasheet allows up to 261 plates, and part numbers on file run from 50 to 200. Adding plates adds channels in parallel, which lowers pressure drop and brings the approach temperature closer for a given flow.

The 335.5 GPM ceiling is set by the ports and stays where it is. Weight grows by the published formula, 13.10 kg plus 0.432 kg per plate: a 200-plate unit is about 99.5 kg (219 lb) empty, so plan the lift and the base before the unit arrives. Plate Count and Capacity covers the trade-off.

A strainer that stops particles larger than 1.1 mm, the published maximum particle size for the B320LT. Anything bigger can lodge at a channel entrance and stay there.

District heating networks and industrial cooling circuits carry scale, weld bead and magnetite, particularly after commissioning or network repairs, and a blocked channel in a brazed unit cannot be reached mechanically. Put the strainer on each circuit that is open, old or newly welded, fit pressure gauges across the exchanger so a rising pressure drop is noticed early, and clean the strainer after the first days of operation, when most of the debris arrives.

These models are catalogued alongside the B320LT. Each has its own page with its dimensions, materials and part numbers.

SWEP B320HT - High-theta and low-theta variants on one large frame.