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Quotes - Engineering - SalesCondensing moisture where you want it instead of where it falls
A drip pan heat exchanger is a pillow plate run deliberately colder than the room's dew point. Warm, humid air meeting the face gives up its water onto the plate, the water runs down the dimpled surface into a gutter along the bottom edge, and the gutter drains to a trapped line. Hung above a filling line, a cooker discharge or a dock door, it catches the condensation that would otherwise form on the ceiling, the pipework and the structure and drip onto product.
Dew point, slope and drain
The plate works because its face is the coldest surface in the room. Glycol at 28 to 34°F, or chilled water a few degrees above its own freezing point, runs inside a double-embossed plate hung on a slope so underside condensate runs to the gutter. Air rises, cools against the face, condenses, and the dried air drops back; the plate becomes a passive dehumidifier with no fan, no filter and nothing to clean except a flat stainless face. In a cold room it also takes the load off the evaporator coils, which otherwise frost on the same moisture.
The plate is wet every hour it runs and is washed with the room, which is why it is 316L and not 304L. Condensate is near-pure water and harmless, but the sanitizer rinse that follows it carries chlorides, and a plate that sits at 34°F and is sprayed with hypochlorite daily will pit in 304L where the rinse dries on the dimples. A 316L face with a drain gutter that empties fully holds up.
Drip plates are 316L because they are wet by design and washed with chlorinated sanitizer, with 304L only on dry utility headers outside the room. Material & Construction explains how the grade is chosen.
What a drip elimination plate carries
- 316L double-embossed plate, sloped so condensate on both faces runs to the gutter
- Glycol or chilled water at 28 to 34°F; direct refrigerant where the room runs on it
- Mounted on a fall to a gutter welded along the low edge
- Gutter drained to a trapped line so the plate never stands in its own condensate
- Rated 100 psig for glycol, with the refrigerant rating applied where specified
- Edges radiused and the face unpolished but passivated for a washdown room
- Hanging rods or ceiling brackets in stainless, with the plate kept clear of the structure
glycol inside a drip plateGlycol at 28 to 34°F keeps the plate face well below the dew point a packing room usually produces, so moisture lands on the plate and not on the line.
What to send us for a drip plate
A drip plate is sized on latent load: how much water the air carries past it. Room conditions and the sources of moisture matter more than the room's size.
- Room temperature and relative humidity at the worst case, usually right after washdown
- Sources of moisture: open tanks, cookers, dock doors, steam cleaning, product cooling
- Where condensation is forming now and what it drips onto
- Chilled utility available: glycol or chilled water temperature and flow, or refrigerant
- Ceiling height, structure, and the clear area above the line where plates can hang
- Sanitizer used in the room, because chlorinated washdown sets the grade
- Whether the plates must be removable for the room's cleaning cycle
Call and talk it through with an engineer: 1-805-484-2992
A chilled pillow plate hung above a product line to gather condensation where it can be drained, instead of letting it fall onto open product or packaging. The plate is pitched to a gutter so the water leaves the room by a drain line.
Sizing and placing a drip elimination plate
The load on a drip plate is latent, not sensible. A packing room at 50°F and 90 percent relative humidity, with a cooker discharging into it, carries far more water in its air then a dry warehouse at the same temperature, and each pound of water condensed releases about 1,000 Btu onto the plate. The plate's job is to condense that water faster than the ceiling and pipework do, so it has to be colder than they are and present enough surface to the moving air. We size from the room condition, the moisture sources and the glycol temperature, and place the plates over the points where condensation is already forming.
Placement decides whether the plate helps. Hung directly over a product line, it intercepts the moist air rising from product and washdown before it reaches the ceiling. Hung in a corner, it dries the corner. Several smaller plates spread along a line do more than one large plate at the end of it, and each one needs its own gutter and drain. Keep the plate a few inches below any ceiling structure so air can circulate over both faces; a plate pressed against the slab condenses on one side and lets the slab condense on the other.
Glycol is the usual utility because most plants already run it to their coolers, and 28 to 34°F supply gives a face temperature far enough under the dew point to work, with the warmer end of the band usually keeping frost off the plate. Chilled water at 38 to 42°F works in a warmer processing room but is marginal in a cold room, where the dew point is already low. Direct refrigerant gives the coldest face and the risk of a frosted plate that stops condensing and starts shedding ice; a defrost cycle or a tempered refrigerant feed handles it.
The gutter is the part that is usually underbuilt. It runs the full low edge of the plate, is welded continuously so nothing leaks past it, slopes to a single outlet, and drains through a trap to a floor drain or a sanitary waste line. A gutter that overflows at washdown, or one with a low spot that holds water, puts the drip back under the plate and breeds the growth the plate was installed to prevent. The outlet gets a removable strainer, and the whole gutter has to be reachable with a hose.
The grade decision is not about condensate, which is near-pure water, but about the washdown. A 304L drip plate in a room sanitized with hypochlorite shows pits along the dimples within the first year, where rinse dried on a cold face and concentrated its chlorides. 316L is the standard here; in a room on a brine spray or a quaternary sanitizer with high chloride carriers, specify a potable-water rinse after sanitizing and keep the plate in 316L.
A drip plate without a gutter is a drip pan with a delay.
Every plate gets a continuous welded gutter, a slope to one outlet and a trapped drain line, or it moves the condensation problem rather than removing it.
Request a QuoteQuestions on drip elimination plates
It handles the moisture over the line it hangs above, not the whole room's latent load. In a packing room with one or two condensation sources it is often enough, and it does its work without a fan or a filter. A room with a large open vat or constant dock traffic still needs mechanical dehumidification, and the drip plates then protect the critical lines while the air unit handles the bulk.
The face frosts if the glycol runs too cold for the room, which is why 28 to 34°F supply is the usual band. Frost on the plate is fine until it insulates the face and stops condensation; then it sheds. In a cold room that already sits near freezing we tune the glycol warmer or add a scheduled defrost. Send the room temperature and we set the utility to match.
With the room. The face is flat, the edges are radiused and the gutter is open on top, so a hose and the room's sanitizer reach every surface. The plate hangs from stainless rods or brackets and can be lowered for a deep clean if the room's cycle calls for it. The one rule is to rinse chlorinated sanitizer off with water before the plate goes cold again, because dried hypochlorite on a cold 316L face is the main corrosion risk the plate has.
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