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Quotes - Engineering - SalesCompressed Air Dryers for Woodworking Shops
A woodworking shop uses compressed air at the bench and inside the machines: nailers, staplers and clamps at every assembly station, the edgebander's pressure rollers and glue pot, the wide-belt sander's tracking and platen loading, the CNC router's tool changer, the finishing room's spray guns and, biggest of all on a plant scale, the pulse-jet valves that clean the bags in the dust collector. A two-person cabinet shop runs a 5 or 7.5 hp piston compressor; a millwork plant with a dust collector and a finishing line runs a 25 to 50 hp screw at 110 to 230 SCFM.
Water in that air is easy to see in a woodshop. A nailer that spits rusty water onto a maple panel leaves a stain the finish will not cover, a spray gun with water in the line throws fisheyes and blushing into lacquer, an edgebander's pressure rollers rust and mark the tape, and a dust collector's pulse valves on the roof fill with condensate and freeze shut in the first cold snap, so the bags blind. Oil aerosol from a lubricated compressor does the same damage to a finish as the water, and it is harder to wipe off.
A refrigerated dryer holding a 38°F pressure dew point covers everything inside a shop kept above 50°F. The catch is the compressor: a two-stage piston unit with no aftercooler discharges 180°F air, and a standard dryer rated for 100°F inlet loses most of its capacity on it. On that compressor use the HTR Series or HRHT Series, built for 180 and 200°F inlet air with the separator and drain inside, or pipe the compressor to a receiver first and let the tank cool the air before a standard dryer. A screw compressor with its own aftercooler feeds a standard dryer directly.
Woodshops run one shift, and the compressor spends the other 16 hours holding pressure for the dust collector's pulse valves. Below 50 SCFM a non-cycling dryer draws so little power that a cycling one cannot pay back; at 100 SCFM and up a TMC Series thermal-mass dryer that stops its refrigeration compressor overnight and through lunch does pay, especially on a demand-charge tariff. Fit a 1 micron prefilter and a 0.01 micron afterfilter, and put the dryer where sawdust cannot reach its condenser.
Request a woodshop dryer quote
Piston discharge with no aftercoolerAir at 180°F overwhelms a dryer rated for 100°F inlet, so the compressor type is the first thing this page asks about, before any SCFM figure.
What wet or oily air does in a woodshop
The damage a tank full of water does before anyone notices
- Rust stains from nailers and staplers on panels headed for a clear finish
- Fisheyes and blushing in lacquer and conversion varnish from water and oil in the gun line
- Rusted edgebander pressure rollers marking the tape, and glue pots pressurized with wet air
- Dust collector pulse valves frozen shut on the roof, bags blinding, suction lost
The dryer specification for a woodworking shop
Match the dryer to the compressor first
- High-inlet-temperature dryer (180 to 200°F rated) on a piston compressor without an aftercooler; standard dryer on a screw
- 38°F pressure dew point, ISO 8573-1 class 4, from a standard dryer; 50°F class 6 from the high-inlet type
- 1 micron prefilter and 0.01 micron oil-removal afterfilter; carbon filter on the finishing room drop
- Dryer sited away from sawdust, condenser cleaned monthly, wall bracket where floor space is short
Dryers that fit a woodworking shop
The high-inlet-temperature dryers are rated at 180 and 200°F inlet, the standard dryers at 100°F, all at 100 psig. A 5 to 10 hp piston compressor delivers 18 to 40 SCFM, a 25 to 50 hp screw 110 to 230 SCFM.
| SERIES | TYPE | FLOW RANGE | MAX INLET | MAX PRESSURE |
| HTR Series | High Inlet Temperature | 25 to 125 SCFM | 180°F | 232 psig |
| HRHT Series | High Inlet Temperature | 25 to 100 SCFM | 200°F | — |
| HPRB Series | Non-Cycling | 7 to 50 SCFM | 120°F | 200 psig |
| DXR Series | Non-Cycling | 10 to 4,200 SCFM | 131°F | 203 psig |
| TMC Series | Thermal Mass Cycling | 30 to 635 SCFM | 140°F | 210 psig |
| GFN Series Filters | Compressed Air Filter | 6 to 1,500 SCFM | — | 232 psig |
| GHTN High-Temperature Filters | Compressed Air Filter | 15 to 1,600 SCFM | — | 150 psig |
| Snap-Trap & Trip-L-Trap Drains | Condensate Drain | Call for sizing | — | 175 psig |
A woodshop air system holds up when it has these.
- Zero-loss drain on the receiver so slugs never reach the dryer
- Dryer condenser in clean air and blown down monthly
- Booth drop with coalescer, carbon filter and regulator after them
The tank drains first, then the dryer drains, and both need attention
A piston compressor's receiver collects most of the water in a woodshop, and a receiver that is never drained fills until it sends slugs of water down the line that no dryer can handle. Fit a zero-loss drain on the tank, a pneumatic Snap-Trap or Trip-L-Trap on a small system, and the dryer only sees vapor and mist. The dryer's own drain is the second point: a float drain with sawdust in its seat holds water in the separator until the outlet air carries it out. Check both on the day the compressor's oil is changed.
- Fit a zero-loss drain on the receiver so water never reaches the dryer as a slug
- Test the dryer's drain monthly; a stuck float shows up as water at the nailer
- Pipe drain discharge to an oil-water separator, not the floor drain
Where the dryer goes in a woodshop
Compressor, receiver, prefilter, dryer, afterfilter, then the shop loop, with the finishing room on its own drop carrying a carbon filter. Keep the dryer out of the sawdust. Its air-cooled condenser pulls room air through a fin pack, and in a shop that pack blinds with fine dust in weeks, after which the dryer runs hot, loses capacity and eventually trips on high pressure. A compressor closet with a filtered louver, or a corner upstream of the dust collector's intake, is the right spot, and the condenser gets a blow-down at the same time as the compressor's own cooler.
Sizing to a piston compressor
A two-stage piston compressor delivers about 3.5 to 4 SCFM per hp, so a 7.5 hp unit makes 26 to 30 SCFM and a 10 hp unit 35 to 40. The HTR Series covers 25 to 125 SCFM and the HRHT Series 25 to 100 SCFM at their rated inlet temperatures, so a 10 hp compressor lands on the HTR 50 or the HRHT 60. The 7.5 to 10 hp reciprocating page matches each compressor size to a dryer.
The dust collector on the roof
Pulse-jet baghouses sit outdoors, and the compressed air line that feeds their diaphragm valves runs outside with them. Air dried to 38°F still condenses in a pipe at 20°F, and the valves are the low point where it collects and freezes. Where the run is short and the climate mild, insulating and heat-tracing the outdoor pipe and fitting a drain at its low point is enough; in a northern winter the collector's header wants a small desiccant dryer at the roof, fed by the shop's refrigerated dryer so the desiccant sees little water. Either way, the refrigerated dryer at the compressor is the first line.
Finishing room air
Spray finishing is the one place in a woodshop where the air touches the product, and lacquer, conversion varnish and waterborne finishes all show water and oil as fisheyes, blushing or poor flow-out. Run the finishing room on a dedicated drop from the dried header, with a 0.01 micron coalescing filter at the booth and an activated carbon filter behind it, and a regulator after the filters rather than before. The paint spraying page covers the booth in more detail.
Choosing a dryer for a cabinet or millwork shop
Away from the dust, with clean air for its condenser. The dryer pulls room air through a finned condenser, and wide-belt sander dust packs those fins within weeks; the unit then runs hot, loses capacity and finally trips. A compressor closet with a filtered louver works, as does a corner on the clean side of the dust collector intake. Where neither exists, blow the fin pack down every month and log it alongside the compressor service.
Because the valves are on the roof and the air feeding them leaves the heated building. A 38°F pressure dew point is plenty indoors, but a pipe at 20°F on a January night condenses water, and the diaphragm valves are the low point where it gathers. On a short run, heat-trace and insulate the pipe and put a drain at its low point. On a long run in a cold climate, give the collector header its own small desiccant dryer fed from the shop dryer.
It needs cleaner air, not a diffrent dryer. Lacquers and conversion varnishes show oil and water as fisheyes and blushing, so the booth gets its own drop off the dried header with a 0.01 micron coalescer at the booth, an activated carbon filter after it and the regulator last. Taking the booth drop off the bottom of the header, or putting the regulator ahead of the filters, undoes most of that, and the finisher sees defects that look like a gun problem.
Sometimes, on a light duty cycle. A two-stage piston unit with no aftercooler discharges near 180°F, and the receiver sheds much of that heat while the compressor runs intermittently. Run it hard through a production day and the tank warms up, the dryer inlet climbs past its rating and capacity falls away. For a compressor that loads most of the shift, the high-inlet-temperature dryer rated for 180 to 200°F is the safer pick, accepting its 50°F dew point.
More on drying woodshop air
Dryers for 7.5 to 10 hp reciprocating compressors
The compressor most woodshops run, matched to the high-inlet-temperature and 5 to 50 SCFM dryers that fit it.
Learn More
Textiles
A weave room runs around the clock, and a dryer that must come off line for service takes the looms with it unless the plant has planned for it.
Learn More
HVAC Controls
A refrigerated dryer with fine filtration ahead of the pressure-reducing valve is what stands between the compressor and a thousand small orifices.
Learn More
