SWEP B320HT

After the HT or LT, look at the next letters. In B320HTH the final H is the plate type, and the published example reads H+L, a pack that mixes two plate types. Losing the +L changes the selection.

Then the pass field and plate count. Our catalogued builds run from 60 to 257 plates. The single-pass ones are written 4x2 1/2 in, and the two-pass one is written 2x2 1/2 in / 2x2 1/2 in. That is visible on the unit even with the plate unreadable, because a two-pass pack has connections on both ends.

Finally the class letter. The builds on file are S, and the published example is M.

For a like-for-like replacement, the complete designation with connections. For anything else, the duty and the pump head.

Head matters on this frame because the HT plate uses pressure drop to gain heat transfer. Send the pressure drop each circuit can spare, as well as the flows and the four temperatures.

With that we can run the selection both ways and show whether an HT pack or the B320LT with more plates is the better fit.

Pressure drop, mainly. Glycol is more viscous than water, and the HT plate already has the higher pressure drop of the two B320 patterns, so the two effects stack. A pack that sits comfortably inside the pump curve on water can exceed it on a strong glycol mixture at low temperature.

Size it on the real mixture and the coldest operating temperature.

Freeze protection is the other reason glycol is in the loop. A heat recovery or process unit left full of water in an unheated space over a shutdown can split the pack. Drain it or protect it.

Each channel holds 0.19 dm3. A pack has one channel fewer than it has plates, shared between the two sides, so the 257-plate build holds about 24 liters per side and a 100-plate unit under 10.

That is very little water against the flow going through it, so the outlet temperature follows a control valve movement almost at once. This is useful for instantaneous heating, and it is also why an oversized or fast-acting control valve hunts on a plate exchanger where it was stable on a storage vessel. The control valve should be sized for the actual load, with its response slowed.

The same figure goes into the expansion vessel and glycol fill calculations.

Use the published formula with the plate count: 13.33 kg plus 0.389 kg per plate. That is about 52 kg at 100 plates and 130 kg (287 lb) at the 300-plate maximum, dry. A full 300-plate pack holds another 57 liters or so of fluid.

At those weights the unit sits on a floor stand or a welded frame under the pack, with the pipework supported separately so the connections carry nothing.

Lift with slings around the pack. Lifting by the connections is the usual handling damage: it can crack the port braze, and the leak shows up only when the system is pressurized. Mounting and piping has the support details.

These models are catalogued alongside the B320HT. Each has its own page with its dimensions, materials and part numbers.

SWEP B320LT - A large copper-brazed plate heat exchanger for district heating and oil cooling.