SWEP PI190

SWEP publishes PED, UL and KHK for the PI190. PED is the European pressure equiptment approval, UL is the recognition a North American inspector looks for on a refrigerant-side component, and KHK covers high-pressure gas equipment in Japan.

Two cautions. First, an approval applies to the unit as stamped: the pressure class letter in the designation is a category, and the rating on the nameplate is what governs. Second, ASME and CRN are not on the published list for this model. If the job specification calls for either, say so in the quote request and we will confirm what can be supplied. More on this under Approvals and Certifications.

In place, by circulating a cleaning solution through the water side and rinsing afterward. The unit is brazed and cannot be opened, and the copper braze means the cleaner must be safe for copper as well as stainless steel. Running the solution against the normal flow direction clears deposits faster.

On an evaporator, do not let fouling run. A dirty water side shows as rising water pressure drop and a falling evaporating temperture, and reduced flow through partly blocked channels is how an evaporator ends up freezing locally.

SWEP publishes a maximum particle size of 0.8 mm for the PI190, so the strainer on the water inlet has to stop anything larger than that. That is tighter than the 1 mm published for several other frames, and a strainer carried over from a different exchanger may be too coarse.

The reason is specific to evaporator duty. Debris that lodges at the channel entrances starves those channels of water, the water left in them gets colder than the rest, and it can freeze and split the plate pack. Clean the strainer after commissioning, when pipe scale and weld slag are moving, and again whenever water pressure drop climbs.

Up to 140. There are no catalogued PI190 part numbers on file, so each unit is configured for its duty within SWEP's published 60 to 150 kW range.

More plates lower the water-side pressure drop and tighten the approach, so the evaporating temperature sits closer to the leaving water temperature. The costs are depth, weight - each plate adds 0.289 kg (0.637 lb) - and refrigerant charge, since every added channel holds refrigerant. Past a point, extra plates also slow the refrigerant in each channel and the evaporator becomes less stable at part load. Plate Count and Capacity covers the trade-off.

These models are catalogued alongside the PI190. Each has its own page with its dimensions, materials and part numbers.

SWEP FI190 - Part of the 190 range, designed around R32, R454B and R290.