SWEP B222

Match the plant. Weld ends suit ammonia and other duties where every joint is a potential leak. Flanges suit process and pure-water lines that have to come apart. Threaded ports work on the smaller lines, but stainless threads gall, so they need the right sealant and care on assembly.

At flows approaching the 43 m3/h (189.32 GPM) ceiling the lines are large, and flange or weld is the practical choice.

Do not reuse B221 spool drawings. The two frames share the 529 x 271 mm outline, but the B222 port centres are 439 x 179 mm, and the difference is enough to stop a welded or flanged spool from lining up.

Vertical, with the two fluids in counter-current. On an ammonia evaporator, liquid enters at the bottom and vapor leaves at the top. On a condenser, vapor enters at the top so the liquid drains down and out. Mounted on its side, a two-phase unit will not distribute or drain properly.

For liquid-to-liquid duty the orientation is less critical thermally, but vertical still lets the pack vent and drain.

A 150-plate B222 weighs about 94 kg (208 lb) before it is filled. Support it under the pack and support the pipework seperately. With weld or flange connections, a line that has to be pulled into position will load the port joints permanently, so fit the spools to the unit as it sits.

Either the designation off an existing unit or the duty for a new one. We hold no catalogued part numbers for this frame, so each B222 is quoted as a configured build.

For a replacement, send the whole string, including the SPS material code and the pressure class.

For a new duty, send both fluids by name and concentration, the flow and the inlet and outlet temperture on each side, the allowable pressure drop on each side, the design pressure and temperature, and the connection type and pipe standard.

Chloride-bearing fluids. The plates are 316, which pits in seawater, brackish water, pool water and heavily chlorinated cooling water. Copper-free does not mean corrosion-proof. Check both sides of the exchanger: an ammonia condenser rejecting heat to river or tower water is only as good as that water.

The opposite mistake is paying for stainless braze when nothing calls for it. If neither fluid attacks or picks up copper and the temperature is under the roughly 185 C ceiling of copper braze, an SC build does the job.

Where the driver is temperature or ammonia alone, the nickel-brazed SN construction is the other copper-free route. Plate and brazing materials compares them.

PED, UL and KHK are the published approvals. The pressure class is a separate matter. The published example build is S class, the 31 bar at 155 C category.

Treat that as a category. The figures that govern are the design pressure and temperature stamped on the unit, and they have to cover the relief valve setting on each side. On an ammonia system, the high side and the low side usually have different design pressures, so quote both.

If the project specification asks for ASME or CRN, raise it with the quote request. ASME covers -40 C to +150 C and CRN covers -196 C to +225 C, so a hot process stream above 150 C changes which stamp can apply.