Ingersoll Rand 99273906 Air Filter Element | M37 Compressor OEM Part

Product Overview

99273906 is the intake air filter element for the Ingersoll Rand M37 rotary screw air compressor. It mounts inside the air filter housing at the intake, upstream of the inlet valve. As the machine draws in ambient air, dust, grit, fibres, water mist and oil mist are captured by the media before reaching the airend — surface filtration stops coarse particles, depth filtration holds fine ones. Only clean air is allowed into the rotor mesh zone.

Filter condition directly affects airend life. Unfiltered air accelerates rotor and bearing wear and contaminates the downstream separator element, oil filter and lubricant, shortening all three at once. A heavily loaded element also restricts intake flow, reducing output and raising energy consumption. Replacing the air filter on schedule is the lowest-cost protection available for the compressor.

Key Specifications

• Part number: 99273906
• Application: Ingersoll Rand M37 rotary screw compressor
• Air delivery: 6 m³/min @ 0.7 MPa
• Outside diameter: 270 mm
• Height: 120 mm
• Effective filtration area: approx. 1.3 m²
• Filtration rating: 2–10 μm
• Filtration efficiency: ≥98% for particles ≥5 μm
• Initial pressure drop: approx. 0.5–1.0 kPa
• Change-out indicator setting: 6.0–6.5 kPa
• Recommended service interval: approx. 2,000 hours or 3 months, adjusted to site conditions

Technical Parameters

Filtration Performance

• Filtration rating: 2–10 μm
• Filtration efficiency: ≥98% for particles ≥5 μm
• Dust holding capacity: approx. 380 g
• Filter classification: rated per ISO 5011 by efficiency, intake resistance and dust holding capacity; the EN 779 G/M/F ventilation filter classes do not apply

Flow and Resistance

• Rated air flow: matched to M37 delivery of 6 m³/min @ 0.7 MPa
• Face velocity: approx. 0.077 m/s
• Initial pressure drop: approx. 0.5–1.0 kPa
• Operating differential range: approx. 1.0–6.0 kPa
• Alarm / final resistance: 6.0–6.5 kPa
• Energy relationship: every 1 kPa of intake resistance adds roughly 1% to machine energy consumption

Dimensions and Installation

• Outside diameter × height: 270 mm × 120 mm
• Construction: pleated media, rolled
• Effective filtration area: approx. 1.3 m²
• Pleat count: approx. 150
• Pleat spacing: approx. 4.8 mm
• Mounting: end-cap located, matched to the M37 air filter assembly
• Sealing: face seal, axially compressed

Materials

• Media: imported wood-pulp filter paper
• Media weight: approx. 130 g/m²
• Inner and outer support: galvanised steel perforated cage, approx. 0.6 mm sheet, open area ≥45%
• End caps: metal (galvanised steel) with polyurethane adhesive
• Seal: NBR rubber gasket
• Bonding layer: polyurethane hot-melt adhesive

Operating Conditions

• Working temperature: −10 to +100 °C
• Relative humidity: ≤80% RH, no condensation
• Media burst strength: approx. 200–400 kPa (per ISO 2758)
• Collapse resistance: designed for differential pressure ≥10 kPa
• Special functions: no flame-retardant, anti-static or moisture-resistant rating is specified for this part number

Service Life and Storage

• Service life: approx. 2,000 hours or 3 months
• Actual change interval: shorten to under 1,000 hours in dusty, gritty or humid environments; follow the differential pressure indicator
• Shelf life: approx. 2–3 years, unopened, dry and ventilated storage

Applicable Standards

• Product standard: ISO 5011 — intake air filters for internal combustion engines and compressors, evaluated on efficiency, intake resistance and dust holding capacity
• Commonly cited test standards: ISO 2941 / 2942 / 2943 / 3723 / 3724 / 3968
• Note: the ISO 29xx / 37xx series are general test methods for hydraulic fluid power filter elements. Where a supplier can only provide hydraulic filter standards, request ISO 5011 data or the original specification sheet.

Installation and Maintenance Steps

Single-person job, approximately 20–30 minutes.

1. Shut down, isolate and depressurise. Press stop or emergency stop, disconnect the main supply and apply lockout/tagout. Open the receiver drain valve and wait until the separator tank gauge reads zero. Criterion: gauge at 0 and no residual air flow.
2. Access the air filter housing. The filter assembly sits at the intake end of the M37. Release the housing clamp or end-cover bolts and remove the cover. Criterion: cover undistorted, clamp not seized.
3. Remove and inspect the old element. Pull the element out vertically and check dust distribution and media condition. Criterion: replace immediately if the media is torn, holed, de-bonded from the end cap or the seal face is flattened — even before the interval is reached. Black oily sludge on the outer surface indicates abnormal oil mist in the intake; check the upstream environment.
4. Clean the housing interior. Wipe the inner wall and base with a lint-free cloth. Do not blow compressed air into the housing — this drives dust into the intake passage. Criterion: no loose dust, seal face flat and clear.
5. Verify the new element. Compare with the old part: 270 mm OD, 120 mm height, seal strip complete with no gaps, media undamaged. Criterion: all three dimensions and the visual check pass. If any item fails, do not install — re-check the part number.
6. Fit the new element and refit the cover. Seat the element vertically, confirm it is fully located at the base and the seal face is not pinching anything. Refit the cover and tighten the clamp or bolts evenly in a diagonal sequence. Criterion: even gap between cover and housing, no skew.
7. Start-up check. Restore power and run for 5–10 minutes. Criterion: no abnormal whistling or intake noise (this usually means the seal is not compressed or the element is not seated); the air filter differential pressure indicator sits in the green zone.

Non-negotiable rule: never start the machine before the element is correctly seated. Running with no element, or with an uncompressed seal, sends unfiltered air straight into the airend and can cause irreversible wear within a short period.

FAQ

Is 99273906 interchangeable with 39588777?

No. 39588777 fits the ML37 / MU37 models and measures 130 mm OD × 250 mm height, while 99273906 fits the M37 at 270 mm OD × 120 mm height. The two are more than double apart in size and cannot fit the same housing. Always confirm by machine model plus part number.

How often should it be replaced?

Under standard conditions, approximately 2,000 hours or 3 months, whichever comes first. In high-dust environments such as cement, foundry, woodworking or mining sites, shorten to under 1,000 hours. The most reliable trigger is the differential pressure indicator — replace when it reaches the alarm position.

What happens if it is not replaced?

Failure propagates through the system. As dust loads the element, intake resistance rises; from 0 to 6 kPa the machine's energy consumption increases by roughly 6.3%. If the media tears or the seal fails, unfiltered air enters the airend and dust contaminates the rotors, bearings, separator element, oil filter and lubricant — turning a filter-level cost into an airend overhaul.

How do I know it needs changing?

Three signals: the differential pressure indicator enters the alarm zone (approx. 6.0–6.5 kPa); on removal the media is fully covered in dust with no visible pleats; or output falls while current and energy consumption rise. Any one signal means replace.

Can the element be cleaned and reused?

Not recommended. This is a pleated paper element designed as a single-use part. Blowing it out from the inside only removes surface dust; deeply trapped fine particles stay in place, and the air pressure easily damages fibres or distorts pleat spacing, creating invisible bypass paths. A cleaned element can look fine while being functionally failed.

What else should be checked during replacement?

Check the differential pressure indicator for correct reset action, the intake hose for cracks or looseness, the housing gasket for ageing, and the inlet valve for correct operation. These parts work together with the filter; replacing the element alone often leads to repeat intake faults.

Is this a genuine part?

99273906 is the Ingersoll Rand original part number. Always order against the part number itself — it is the only unambiguous identifier. Do not order on the basis of "fits M37" or visual similarity alone.

Do other M-series models use the same element?

No. Air filter specifications differ across the M series: M22 uses 39588470 (130 mm OD), M37 uses 99273906 (270 mm OD), M55 uses 39708466 (278 mm OD) and ML37 uses 39588777. Same series does not mean same element — verify model by model.

What are the most common installation errors?

Two: trapping material on the seal face or tightening the cover before the element is fully seated, which causes leakage; and tightening cover bolts from one side only, which skews the cover. Confirm seating first, then tighten evenly in a diagonal sequence.

Are there storage requirements?

Yes. Moisture makes the paper swell and lose efficiency, and rusts the metal cage. Store on indoor shelving in a dry, ventilated area, off the floor and away from walls, water and oil. Use within 2–3 years while unopened, on a first-in, first-out basis.

Compatible Machine Models

No.	Model	Air delivery	Element OD × height
1	M37	6 m³/min @ 0.7 MPa	270 mm × 120 mm
2	M22	3 m³/min @ 0.7 MPa	130 mm × 151 mm
3	M55	10 m³/min @ 0.7 MPa	278 mm × 125 mm
4	ML37 / MU37	6 m³/min @ 0.7 MPa	130 mm × 250 mm
5	30S	3 m³/min @ 0.7 MPa	130 mm × 123 mm
6	50S	6 m³/min @ 0.7 MPa	216 mm × 318 mm
7	75S	10 m³/min @ 0.7 MPa	278 mm × 251 mm

This page covers row 1 (M37). The remaining rows are listed only as a cross-reference to help you avoid mis-purchase. Note that ML37 / MU37 shares the same air delivery as the M37 but uses a completely different element — equal delivery does not mean an interchangeable filter. If your machine nameplate is not listed, send a nameplate photo and full model number and we will confirm by part number before you order.

Related Service Parts

Seven components in the M37 intake and lubrication system are maintained on a similar cycle. Confirm exact part numbers against the machine parts manual.

Component	Location	Function	Check point
Oil filter element	Main oil circuit, between cooler and airend	Removes wear debris and sludge, protects bearings and rotors	Replace together with the air filter; check housing seal face for weeping
Separator element	Inside the separator tank	Separates oil mist from compressed air and returns oil	Check the return line for blockage — poor return raises oil carry-over
Air filter indicator	On the air filter assembly	Shows element loading and change timing	Should reset correctly when pressed; a reading that never moves means it has failed
Coolant filter element	Coolant circuit, between cooler and filter	Keeps coolant clean, limits scale and debris	Replace together with the oil filter
Thermostatic valve element	Between cooler and filter	Controls coolant flow through the cooler to hold airend temperature	Check first if the machine runs cold or raises a high-temperature alarm
Breather filter	On the separator tank	Balances tank pressure and blocks external dust from the oil circuit	Inspect on the same cycle as the air filter; shorten in dusty sites
Intake hose and housing gasket	Between filter assembly and airend	Keeps the intake path leak-free with no unfiltered bypass	Check for cracks, ageing and loose clamps; bypass leakage is as harmful as no element

In dusty sites we recommend replacing the air filter, oil filter and separator element together to keep maintenance intervals aligned and avoid repeated downtime. Coolant filter and thermostatic valve follow their own schedules.