SWEP B221

Heavier than its footprint suggests. At 10.60 kg plus 0.6 kg per plate, a full 150-plate pack is about 101 kg (222 lb) dry. Each channel holds 0.254 dm3, so the same pack carries close to 38 liters of fluid, which puts the operating weight of a water-filled unit near 140 kg.

Carry that on a floor stand or a bracket under the pack, never on the connections. This matters most with weld connections. Once welded in, the exchanger and the pipe are one rigid assembly, and any pipe movement from thermal expansion goes straight into the port braze. Anchor the pipe close to the unit and allow for expansion elsewhere in the run. See mounting and piping.

The method is the same: circulate a cleaning solution in reverse through the fouled side, then flush. The difference is in the chemistry. With stainless braze there is no copper to protect, so the cleaner only has to be compatible with 316 stainless.

It has to suit the process as well. On pharmaceutical and high-purity water duty, the cleaning agent and the final rinse quality are normally set by the site's validation requirements, so write that into the procedure.

On ammonia duty only the water or brine side is cleaned.

Threaded, flange and weld. There is no solder option, which follows from the all-stainless construction, and no grooved option on the published list.

That affects replacements. If a B221 replaces a copper-brazed unit with solder or grooved connections, the pipework needs transition pieces, and on ammonia it normally becomes welded steel or stainless.

We hold no catalogued part numbers for this frame, so connection size and standard are fixed at the quote. Send the pipe size and schedule for weld ends, the flange standard and rating for flanges, or the thread standard for threaded ports. Port centres are 444 x 184 mm for laying out the spools.

They are the published approvals for the frame: PED for Europe, UL for North America and KHK for Japan. On an ammonia plant the exchanger is one pressure vessel among several, and the authority will want its stamped design pressure and temperature to cover the system design conditions on both sides.

The published example build is M class, a category of up to 45 bar at 135 C. Give us the actual design pressure and the relief settings so the unit is quoted to them.

If the plant specification calls for ASME, note that its envelope is -40 C to +150 C. A low-temperature ammonia duty can sit close to the bottom of that range, so state the lowest evaporating temperature.

It is right when copper cannot be in the wetted path. That means ammonia, which attacks copper braze, and deionized or ultrapure water, which leaches it. The 27 m3/h (118.88 GPM) ceiling and 150-plate maximum set the size of duty it can take.

It is more than the job needs on ordinary water, glycol or common refrigerants. A copper-brazed 316 unit does that work at lower cost.

It is the wrong material for chlorides. The plates are 316, which pits in seawater, brackish water and pool water, and removing the copper does nothing for that. For flows above this frame's ceiling in the same construction, the B222 shares the envelope.