Compressed air for laundry and dry cleaning

Where is compressed air used in a laundry?

Laundries range from a small dry-cleaning shop with one press and a spotting board to large commercial, hotel and hospital laundries running tunnel washers and automated finishing lines. Almost every machine apart from simple washers uses air somewhere, usually in cylinders and valves. The table lists the main users. Values are typical; the laundry equipment maker’s data always takes priority.

Presses, finishers and spotting: why air quality matters

Garment and utility presses use air cylinders to close and open the head, hold clamps and sometimes create vacuum or blowing. Form finishers blow air through garments to shape them. Spotting guns spray cleaning fluid or air jets onto stains. In all these, air touches fabric, directly or indirectly.

Wet air carries water and rust from pipes into valves and onto garments, causing water spots and brown marks. Oil carry-over from a worn compressor separator or overfilled sump can leave oily stains that are hard to remove. Both lead to rewash and customer complaints. A dry-cleaner’s reputation is often damaged by air problems that are cheap to fix.

Recommended treatment for most laundries:

1. Compressor in good condition, with the separator and oil level maintained to stop carry-over.
2. Air receiver with an automatic drain.
3. Refrigerated dryer giving about +3 °C pressure dew point, sized for summer temperatures in the laundry plant room.
4. General-purpose and coalescing filters after the dryer, with differential-pressure indicators.
5. Point-of-use filters and regulators at spotting boards and finishers.

Where air blows directly onto clean garments, an oil-free compressor or very effective oil removal is worth considering.

Tunnel washers and large commercial laundries

Large laundries, including those serving hotels, hospitals and railways, run continuous batch tunnel washers, water-extraction presses, shuttles, dryers and automated finishing lines. These systems use many air-operated valves, gates and cylinders, and a loss of air stops the whole line. Demand is continuous over two or three shifts.

For these plants, design for reliability:

• Two or more screw compressors, so the line keeps running if one is serviced or fails.
• A dryer with bypass and isolation, or two dryers, so treatment maintenance does not stop production.
• A properly sized receiver to cover peak demand when several presses and shuttles move together.
• A ring main with drops from the top of the pipe and drain legs at low points.
• Pressure monitoring at the line, not only at the compressor.

Hospital and hotel laundries

Hospital laundries handle soiled and infected linen and must follow infection-control procedures for separation, washing temperatures and handling. The compressed air in the laundry is for machinery, not medical air; medical air is a different system governed by its own standards. Laundry air should still be dry and clean to protect valves and keep linen free of marks.

Hotel laundries usually run one or two shifts with garment presses, ironers and folders. Many hotels share one compressor between the laundry, workshop and building controls; in that case the laundry branch should be isolated and filtered so its leaks and peaks do not disturb other users. Our hotels and commercial buildings page covers the wider building system.

Sizing a laundry compressor

Laundry compressors are often bought by horsepower alone and then found too small when a new press is added, or far too large for a small shop. A sound method:

1. List every air-using machine and its consumption from the maker’s manual, usually given in litres per minute, cfm or m³/h at a stated pressure.
2. Estimate which machines run at the same time during the busiest hour.
3. Allow for leaks and future machines, typically by adding a reasonable margin rather than doubling.
4. Set the pressure from the highest machine requirement plus losses in dryer, filters and piping.
5. Choose a receiver large enough to handle the short peaks of press cycles.

Small dry-cleaning shops often suit a tank-mounted piston compressor with a small dryer. Medium and large laundries running long hours usually suit screw compressors, which handle continuous duty better and are quieter.

Energy and leaks

Laundries are full of potential leaks: press heads, quick couplings, worn cylinder seals and hose reels. A common pattern is a compressor loading all night because of leaks while the laundry is closed. Practical steps:

• Close the laundry main isolating valve at the end of the last shift, or switch off the compressor if nothing else needs air.
• Listen for leaks during a quiet period and record them for repair.
• Set pressure to what the machines need; every extra bar costs about 7% more power.
• Replace worn cylinder seals and valves during planned maintenance.

Laundries also use a lot of steam and hot water. Heat recovered from an oil-injected screw compressor can preheat wash water, which is worth evaluating in larger plants.

Indian context

Commercial laundries are growing in Hyderabad, Secunderabad and Andhra Pradesh cities, serving hotels, hospitals, railways, institutions and app-based consumer services. Many dry-cleaning shops operate in small premises with limited ventilation. Summer temperatures inside laundries, which already carry heat from dryers and ironers, often exceed 40 °C. This pushes compressors towards high discharge temperatures and overloads dryers unless plant rooms are ventilated.

Lint is a particular issue. Lint drawn into compressor intakes and coolers blocks airflow and causes overheating, so compressors should take their air from a clean, cool space away from tumble dryers and ironers. Power dips and generator changeovers can stop compressors mid-shift; restart settings and standby protect production.

Common problems and fixes

How much air does each laundry machine use?

Laundry machines use air in short strokes, not as a steady stream, so nameplates and catalogues often quote very different figures. The table gives planning values for average free air while a machine is working at a normal rate, at 5.5–7 bar(g). Use the maker’s figure where you have it; use these where you do not.

A quick check on a press: a 100 mm bore cylinder with a 150 mm stroke and a 25 mm rod sweeps about 2.28 litres in and out. At 6 bar(g) that is 2.28 × 7.013 ÷ 1.013 = 15.8 litres of free air a cycle. At one cycle every 30 seconds it uses 0.53 l/s, or about 1.1 cfm. Presses with two heads or extra clamps use proportionally more.

Sizing examples: a small dry cleaner and a hotel laundry

Small dry-cleaning shop (illustrative). Multiply each machine’s working average by the share of the busy hour it actually works.

• Dry-cleaning machine: 1.5 cfm × 1.0 = 1.5 cfm
• Two utility presses: 2 × 2.5 cfm × 1.0 = 5.0 cfm
• Form finisher: 4 cfm × 0.8 = 3.2 cfm
• Spotting gun: 3 cfm × 0.3 = 0.9 cfm
• Blow gun: 9 cfm × 0.05 = 0.45 cfm

Average demand is 11.05 cfm. With 10% for leaks it is 11.05 × 1.10 = 12.2 cfm. A piston compressor should not run more than about 60% of the time, so its free air delivery (FAD) should be at least 12.2 ÷ 0.6 = about 20 cfm at 7–8 bar(g). That points to a two-stage tank-mounted unit. Check the FAD figure, not the displacement: on piston machines the displacement is often 30–50% higher than the air actually delivered.

The tank sets how often the motor starts. Cycling is worst when demand is half the FAD. For 20 cfm (9.44 l/s), a 2 bar band between cut-in and cut-out, and no more than 15 starts an hour (240 s a cycle), the volume needed is 9.44 × 1.013 × 240 ÷ (4 × 2) = 287 litres. A 300 litre tank fits. Check the motor maker’s limit on starts per hour.

Hotel laundry (illustrative). Three washer-extractors (3.0 cfm), a flatwork ironer with folder (10.0 cfm), three utility presses (7.5 cfm), a form finisher (3.2 cfm), a shirt finisher (6 × 0.8 = 4.8 cfm), a dry-cleaning machine (1.5 cfm), two spotting guns (2 × 3 × 0.3 = 1.8 cfm) and a blow gun (9 × 0.1 = 0.9 cfm).

• Average demand: 32.7 cfm.
• Plus 10% for leaks: 32.7 × 1.10 = 36.0 cfm.
• Plus 15% for growth: 36.0 × 1.15 = 41.4 cfm (1.17 m³/min).

Over two shifts, a screw compressor suits this load better than a piston unit. Choose one with an FAD of about 1.2–1.4 m³/min (42–49 cfm) at 7.5 bar(g); this is commonly the 7.5–11 kW class, but confirm on the FAD sheet. For load-unload control with a 1 bar band and no more than 60 load cycles an hour, a 1.3 m³/min machine (21.7 l/s) needs 21.7 × 1.013 × 60 ÷ (4 × 1) = about 330 litres, so fit a 500 litre receiver. For standby, the ironer, folder and washers need 13 × 1.10 = 14.3 cfm, which a piston unit of about 15–20 cfm FAD can carry while the screw is serviced.

Oil-free or oil-injected with filtration for garment-contact air

Air that touches clean fabric, from spotting guns, finishers and blow-through boards, should meet ISO 8573-1 oil class 1 or 2. That means no more than 0.01 or 0.1 mg/m³ of total oil. There are two ways to get there.

A practical split for larger laundries is to run an oil-injected screw for the whole plant and add a coalescing and carbon filter set only on the branch serving spotting boards and finishers. Fit differential-pressure indicators, and change elements on a date as well as on the indicator: carbon elements do not show pressure drop when spent. See compressed air filtration and scroll compressors.

Noise, heat and where to put the compressor in a shop

An open piston compressor often produces about 80–90 dB(A) at 1 m; an enclosed screw unit typically about 65–72 dB(A). In open space, sound falls about 6 dB each time distance doubles. A unit producing 85 dB(A) at 1 m gives about 79 dB(A) at 2 m and 73 dB(A) at 4 m. Inside hard-walled shops the fall is smaller, because sound reflects. Put a piston unit at the back of the shop or in a ventilated store room, never beside the counter.

The compressor also needs cool air. A 3.7 kW (5 hp) piston unit turns its whole electrical input into heat: at a motor efficiency of about 86%, that is 3.7 ÷ 0.86 = 4.3 kW. Holding its room to 8 °C above a 40 °C ambient needs 4.3 ÷ (1.13 × 1.005 × 8) = 0.47 m³/s, or about 1,700 m³/h. That is far more than a closed cupboard gives, so plan a louvre low on one wall and an exhaust high on the opposite wall.

• Draw intake air away from steam presses, tumble-dryer exhausts and boiler flues.
• Keep lint out: a coarse filter over the louvre is cheaper than a cleaned cooler.
• Stand the unit on anti-vibration pads, and connect it with a short flexible hose.
• Lead condensate to an oil-water separator, not straight into the shop drain.

Maintenance in steam-heated, humid laundry rooms

Laundries load compressors with more water than most factories. At 35 °C and 80% relative humidity, a compressor delivering 40 cfm at 7.5 bar(g) into a dryer at +3 °C pressure dew point removes about 2.1 litres of water an hour: about 17 litres per 8-hour shift and 34 litres over two shifts. Every litre must leave through a working drain.

In steam-heated rooms, also watch for rust on the receiver shell and fittings, and for oil emulsion in the compressor. Milky oil means water is condensing inside a machine that runs too cool or too lightly loaded. Correct the cause, then change the oil. Service planning is covered on compressor AMC.

How Reddy Compressors helps

Reddy Compressors, at Tarnaka, Secunderabad, has served industry since 2002 as an independent multi-brand specialist. We sell, rent and service ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic and other compressors, and we are not an authorised dealer of any brand. We have tie-ups with all major and reputed brands. For laundries and dry cleaners we:

• Size and supply new and used/refurbished piston and screw compressors, dryers, filters and receivers.
• Provide service, AMC and breakdown repair with over 20 service engineers and technicians covering Telangana and Andhra Pradesh.
• Carry out leak surveys and air-quality checks, including dew-point measurement.
• Rent compressors for standby while a main unit is repaired or replaced.
• Identify spare parts from make, model, serial number and nameplate photo, confirm fit before quoting, and supply across India.

Our track record. We have supplied compressors to leading companies in laundry and dry cleaning across Telangana, Andhra Pradesh and beyond – new and used machines, long-term rental, and breakdown cover when a laundry’s own compressor fails – backed by our own service team.

What to send us

• Type of laundry: dry-cleaning shop, hotel, hospital, commercial or tunnel line.
• List of machines with makes and models, or photos of their nameplates.
• Number of shifts and busiest hours.
• Existing compressor and dryer details: make, model, serial and running hours.
• Problems seen: water marks, oil marks, low pressure, overheating or high power use.

Frequently asked questions

What pressure do laundry presses need?

Most garment and utility presses, finishers and folders work at about 5.5–7 bar (79.8–101.5 psig). Check each machine’s manual for its stated working pressure and air consumption, then set the compressor slightly above the highest requirement to allow for losses in the dryer, filters and piping. Setting pressure much higher wastes energy, since each extra bar costs about 7% more power.

Why are there water spots on garments from the press?

Usually because the compressed air is wet. Without a working dryer, water condenses in pipes and is carried into valves and onto garments, often with rust from steel piping. Check that the dryer is running and sized for summer conditions, that receiver and filter drains are working, and that drops are taken from the top of the main. Replace badly corroded pipe sections.

Do dry cleaners need an oil-free compressor?

Not always, but it helps where air blows directly onto garments, such as in form finishers and spotting guns. A well-maintained oil-injected compressor with a refrigerated dryer and coalescing filters gives clean air for most shops. The key is to prevent oil carry-over by maintaining the separator and oil level, and to change filters on time.

What size compressor does a small dry-cleaning shop need?

A small shop with one or two presses and a spotting board usually suits a tank-mounted piston compressor with a small refrigerated dryer and filter. The right size depends on the air consumption of each machine and how many run together. Send us the machine list and we will recommend a compressor and receiver with a sensible margin.

How can a laundry stop its compressor overheating?

Keep the compressor’s cooler free of lint, take intake air from a cool, clean area away from dryers and ironers, and ventilate the plant room so hot air can escape. Check the oil level and condition, and service filters on time. Never bypass the high-temperature shutdown. If the room cannot be cooled, relocating the compressor is often the best solution.

Can you provide a standby compressor for a hospital laundry?

Yes. We rent compressors for standby during breakdowns and planned maintenance, and we can design a permanent two-compressor system with dryer bypass so the laundry keeps running. Hospital laundries handle linen continuously, so a standby plan agreed in advance avoids long stoppages. Our service team covers Telangana and Andhra Pradesh.

What is the best air compressor for dry cleaning?

For a typical dry-cleaning shop with a dry-cleaning machine, two presses, a form finisher and a spotting board, a two-stage tank-mounted piston compressor with about 20 cfm free air delivery and a 300 litre tank is a sound starting point. Add a small refrigerated dryer and a coalescing filter. Where air touches garments, an oil-free unit or an extra activated-carbon filter on that branch protects against stains. Larger and multi-shift laundries are better served by a screw compressor. Size from each machine’s air use, not from horsepower.

How much air does a dry cleaning press or spotting gun use?

A pneumatic utility press typically uses about 1–4 cfm on average while working. A single 100 mm cylinder cycling every 30 seconds at 6 bar(g) uses about 1.1 cfm. Form finishers use about 3–5 cfm for their clamps, and cabinet shirt finishers about 4–8 cfm. A spotting gun uses about 2–4 cfm while triggered, at 3–6 bar(g), but is used only part of the time. A blow gun with an open 2 mm nozzle uses about 8–9 cfm, which is why guns left open waste so much air.

What size air compressor does a hotel laundry need?

It depends on the machine list. In our illustrative hotel laundry, with three washer-extractors, an ironer and folder, three presses, two finishers, a dry-cleaning machine and two spotting guns, average demand is 32.7 cfm. Allowances for leaks and growth bring it to about 41 cfm. A screw compressor delivering about 1.2–1.4 m³/min at 7.5 bar(g) suits this load, with a 500 litre receiver, a dryer sized for 45 °C and a small piston unit as standby.

Where should the air compressor go in a dry-cleaning shop?

Away from customers, steam and lint. Use a ventilated back room or store with a low inlet louvre and a high exhaust. A 3.7 kW piston unit needs roughly 1,700 m³/h of air to stay within 8 °C of a 40 °C ambient. Keep its intake away from presses, tumble dryers and boiler flues. Stand it on anti-vibration pads, connect it with a flexible hose, and lead condensate to an oil-water separator. Piston units are loud, about 80–90 dB(A) at 1 m, so distance and a wall both help.

Related pages

• Industrial applications of compressed air
• Hotels and commercial buildings
• Tank-mounted reciprocating compressors
• Refrigerated air dryers
• Compressor AMC
• Leak detection