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Quotes - Engineering - SalesWhat a single machine asks of its dryer
Short bursts at the machine's peak, cool air, line pressure below 100 psig
One CNC machine, one packaging line, one press or one blast cabinet on a drop from a wet header needs a dryer sized to what that machine draws at its busiest moment. This page reads that number off the machine, turns it into a 15 to 65 SCFM dryer and puts the dryer, filters and bypass on the wall beside it.
The drop delivers air at plant temperature and 80 to 100 psig, so the inlet correction that dominates compressor-room sizing largely disappears. What replaces it is the draw profile: most machines average a few SCFM and peak at several times that during a blow-off, a tool change or a cylinder stroke, and the dryer has to carry the peak.
CNC machining center
- Chuck, tool change and air blast: 10 to 15 SCFM peak
- Dryer size 15 to 20 SCFM
- Through-spindle air blast can double it
Packaging or assembly machine
- Cylinders, grippers, blow-offs: 20 to 30 SCFM peak
- Dryer size 32 SCFM
- Air knives on a labeler push it to 50
Press or pneumatic cell
- Large cylinders and clamps: 25 to 40 SCFM peak
- Dryer size 42 to 50 SCFM
- Short strokes at high rate need a local receiver
Blast cabinet
- 3/16 in nozzle at 80 psig: 45 to 50 SCFM continuous
- Dryer size 50 to 65 SCFM
- The one point-of-use load that never rests
Machine draw to dryer size
Typical peak air draw for common single-machine loads at 80 to 100 psig, with the dryer sized at plant-temperature inlet; the second dryer column applies the 0.92 factor for an 80 psig drop or the 0.88 factor for a machine in a 110°F area.
| MACHINE | PEAK AIR DRAW | DRYER SIZE AT 100 psig | DRYER SIZE AT 80 psig OR 110°F | DRYER BAND |
| Plasma cutting table | 6 to 10 SCFM | 10 to 11 SCFM | 11 to 15 SCFM | 5 to 50 SCFM |
| CNC machining center | 10 to 15 SCFM | 15 to 20 SCFM | 20 SCFM | 5 to 50 SCFM |
| Packaging machine with blow-offs | 20 to 30 SCFM | 32 SCFM | 32 to 42 SCFM | 5 to 50 SCFM |
| Assembly cell with press cylinders | 25 to 40 SCFM | 42 to 50 SCFM | 50 SCFM | 5 to 50 SCFM |
| Blast cabinet, 3/16 in nozzle | 45 to 50 SCFM | 50 SCFM | 55 to 65 SCFM | 65 to 250 SCFM |
| Two machines on one drop | 40 to 60 SCFM | 50 to 65 SCFM | 65 SCFM | 20 to 250 SCFM cycling |
Plug-in non-cycling dryers for one drop
The 7 to 50 SCFM cabinet dryers hang on a wall bracket, plug into 115 V and draw 0.15 to 0.5 kW. At these flows a non-cycling design costs nothing worth measuring to leave running through the shift, and the dew point holds whether the machine is cycling or idle.
- HPRB Series: Current small non-cycling dryer, 7 to 50 SCFM, with low-GWP R513A refrigerant, a 3-in-1 heat exchanger and a built-in separator on the larger sizes.
- DXR Series: Direct-expansion non-cycling dryer in 27 sizes from 10 to 4,200 SCFM; the widest single range on the site, with a full data sheet behind every model.
Cycling dryers for a machine that works in bursts
A press cell that runs 20 seconds a minute, or a blast cabinet used two hours a day, suits a 30 to 65 SCFM cycling dryer that stops its refrigeration compressor between bursts and rides on the thermal mass, which matters where a dozen point-of-use dryers add up.
- TMC Series: Thermal-mass cycling dryer from 30 to 635 SCFM; stores cold in a thermal mass so the refrigeration compressor rests when air demand drops.
- NXC Series: Cycling dryer in 19 sizes from 20 to 2,000 SCFM with a dry thermal mass and up to 80 percent power savings at part load.
Installing a dryer on one machine's drop
The set goes on the wall next to the machine: drop, isolation valve, prefilter, dryer, afterfilter, bypass, then the machine's own regulator and lubricator.
Take the drop off the top of the header, not the bottom, so the slug of water that collects in the main stays out of the branch, and put a ball valve at the top of the drop. The 1 micron prefilter ahead of the dryer catches pipe scale and the oil mist a wet header carries; the 0.01 micron coalescer behind it is what protects the machine's valves and cylinders. Keep the lubricator, if the machine has one, downstream of everything.
A single-body bypass valve serves dryers to 35 SCFM and a three-valve set above that, so the machine keeps running while an element is changed. Mount the dryer with 6 in of clearance behind it for condenser air and outside the machine guarding, where the cabinet heat cannot reach it, and pipe the three drains, two bowls and the dryer separator, to a drain point rather than the floor under the machine.
A machining center that averages 6 SCFM but blasts chips at 15 SCFM gets the 15 or 20 SCFM dryer; sizing it to the average leaves the dryer overrun for the length of every blast.
Size a dryer for one machine
Fitting a dryer to one machine's drop
Measure it. A temporary flow meter on the drop for a full production cycle, read at its highest sustained value over about a minute, beats any estimate. Lacking a meter, add up the cylinders, blow-offs and nozzles from the pneumatic schematic and assume they can fire together. Brochures quote average consumption, and a machining center averaging 6 SCFM can blast chips at 15.
They can. Air knives on a labeler can push a packaging machine from 20 to 30 SCFM to around 50, and a knife blows continuously while the line runs, not in bursts. If the knives are part of the machine, size for them: the 50 SCFM dryer, or the 65 if the drop runs at 80 psig or the area is hot. Otherwise feed the knives from a seperate branch.
That depends on how it is used. A cabinet that runs a 3/16 in nozzle most of the shift is a continuous 45 to 50 SCFM load, and a non-cycling dryer of 50 to 65 SCFM is the plain answer. A cabinet used two hours a day suits a cycling unit that rests the rest of the time. Either way, dry air is what keeps the media flowing freely and the nozzle clear.
Water that gets past the central dryer, or condenses in a cold section of main, runs along the bottom of the pipe. A drop taken from the bottom collects that water and sends it straight to the point-of-use dryer as a slug its separator was never sized for. A tee off the top, with a ball valve at the head of the drop, leaves the water in the main for its drain legs to remove.
