SWEP B9

The two sides of a B9 are not the same size: 0.0175 dm3 per channel on one and 0.0231 dm3 on the other. The stream with the smaller volume flow belongs on the tighter side so its velocity stays up; the larger flow takes the roomier side so its pressure drop stays reasonable.

Total hold-up is small either way. A 30-plate pack has 29 channels, so each side holds roughly a quarter to a third of a liter. That keeps a refrigerant charge low and makes the unit quick to respond. It also means the sides cannot be swapped on a replacement. Pipe the new unit the way the old one was piped.

The plate face is 378.70 x 78.70 mm (14.91 x 3.1 in) and the port centres are 345 x 45 mm (13.58 x 1.77 in). Check the port spacing first.

Then measure pack depth and count the plates, because depth grows with plate count and nothing else tells you the count once the label has gone. Weight is a cross-check: at 0.50 kg plus 0.128 kg per plate, a 30-plate B9 is about 4.34 kg (9.56 lb) dry.

SWEP publishes threaded and solder connections for the B9. Match the type and the size to the unit that came out. The connection string is the last field of the designation, written in port order, so copy it exactly as stamped.

Adapting with bushings or reducers is where replacements go wrong. The datasheet example for this frame, B9H/1P-SC-U, is in the U pressure class, the 64 to 140 bar category used for CO2. At those pressures every added joint is another rated component and another leak path. If the existing pipework genuinely cannot be matched, tell us what is there and we will confirm a connection that suits it instead of leaving you to adapt on site.

Often it is. The fields we need are the plate letter after "B9", the plate count after the "x", the pass arrangement after the slash, the two-letter material code and the final pressure class letter.

For the rest, send the 378.70 x 78.70 mm face measurement to confirm the frame, a plate count taken off the edge of the pack, and clear photographs of all four connections. On a B9 add one more thing: which fluid ran through which pair of ports. The channels are asymmetric, and we need that to put each stream back on the correct side.

The published example for the frame is single pass, B9H/1P-SC-U, and that is the arrangement to expect.

In practice that changes how a short selection is corrected. On most small frames the first move is another pass. On a B9 the levers are plate count, up to the 60-plate maximum, and the way the two streams are assigned to the two channel sizes. If neither closes the duty, the answer is a different frame.

They are pressure-equipment approvals for three markets: PED for Europe, UL for North America and KHK for Japan. For a US installation the UL recognition is the one an inspector or an equipment listing will look for.

Two practical points. If your job needs an ASME stamp or a Canadian CRN, say so with the inquiry - those are separate approvals with their own temperature envelopes, and they are confirmed per build. And on CO2 duty, UL approval wants a relief valve on each side set at 0.9 times design pressure, so the valves belong in the piping design from the start. Details are on Approvals and Certifications.

One with openings smaller than 0.4 mm, on every liquid stream that is not already clean. That is a fine screen. The coarse basket fitted to protect a pump will pass particles that lodge in a B9 channel.

A brazed pack cannot be opened to pull debris out, so anything that gets in stays until it is flushed back out, if it can be. The usual sign is a pressure drop that climbs over weeks on one side only. Fit the strainer close to the inlet and clean it after the first days of running, when construction debris comes through.