Ingersoll Rand M37 Air Filter Element 99273906

99273906 is the intake air filter element for the Ingersoll Rand M37 screw air compressor. It sits inside the air filter housing at the intake, upstream of the inlet valve, and forms the first filtration barrier for the entire compression system. Dust, sand, fibers, water mist and oil mist are captured by the media before air reaches the airend — surface filtration stops coarse particles, depth filtration holds the fines.

Filter condition directly affects airend service life. Hard particles entering the screw element accelerate rotor and bearing wear, and contaminate the separator element, oil filter and lubricant downstream. A heavily loaded filter also restricts intake flow, cutting delivered capacity and raising energy consumption. Replacing the air filter on schedule is the lowest-cost protection available for the airend.

Key Specifications

Item	Value
Part number	99273906
Product name	Air Filter Element
Application	Ingersoll Rand M37 screw compressor
Compressor capacity	6 m³/min @ 0.7 MPa
Outer 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
Alarm differential pressure	6.0–6.5 kPa
Recommended service interval	Approx. 2000 hours (adjust to site conditions)

Technical Data

Filtration performance

Parameter	Value / Note
Filtration rating	2–10 µm (industry range; published values vary 2–10, 3–12, 5–10 and 10–15 µm)
Filtration efficiency	≥98% for particles ≥5 µm
Filter class	Air intake filters are not classified under the EN 779 ventilation filter system (G/M/F). Performance is defined by ISO 5011 using efficiency, intake resistance and dust holding capacity.
Dust holding capacity	Approx. 380 g (calculated from 1.3 m² media area at a typical 300 g/m² for wood-pulp filter paper)
Beta ratio (β)	Not applicable to air filter elements. Beta ratio is a hydraulic and lube filter metric measured by ISO 16889 multi-pass testing. Air filter performance is evaluated by ISO 5011.

Flow and resistance

Parameter	Value / Note
Rated air flow	Matched to M37 capacity of 6 m³/min @ 0.7 MPa
Face velocity	Approx. 0.077 m/s (6 m³/min ÷ 1.3 m², within the typical 0.05–0.15 m/s range for air filters)
Initial pressure drop	Approx. 0.5–1.0 kPa (calculated)
Operating differential range	Approx. 1.0–6.0 kPa (calculated, from clean element to alarm point)
Alarm / final differential pressure	6.0–6.5 kPa (per the compressor differential pressure indicator setting; confirm against the machine manual)
Pressure drop vs. energy	Each 1 kPa of intake resistance raises compressor energy consumption by approx. 1% (calculated)

Pressure drop and energy consumption (calculated)

Intake resistance	Compression ratio	Relative energy increase
0 kPa (new element)	7.91	Baseline
2 kPa	8.07	+2.0%
4 kPa	8.24	+4.1%
6 kPa (near alarm)	8.41	+6.3%

Based on 0.7 MPa gauge discharge pressure and 101.3 kPa atmospheric pressure. Over the full service life of a single element (0 to 6 kPa), compressor energy consumption rises by roughly 6%. On a 37 kW unit running 6000 hours per year, the extra power cost in the later part of the filter's life outweighs the price of the element itself. This is the engineering basis for the OEM differential pressure alarm setting.

Dimensions and installation

Parameter	Value / Note
Outer dimensions	270 mm OD × 120 mm H
Construction	Pleated (wound filter paper)
Effective filtration area	Approx. 1.3 m² (calculated from 270 mm OD / 200 mm ID / 35 mm pleat depth / approx. 154 pleats; approx. 1.7 m² if ID is 165 mm)
Pleat count	Approx. 150 (calculated)
Pleat spacing	Approx. 4.8 mm (calculated: 738 mm mean circumference ÷ 150 pleats)
Mounting interface	End-cap located, matched to the M37 air filter assembly
Sealing	Face seal, axial compression (typical for this element type; confirm against the actual part)

Procurement note: When cross-checking a replacement, 270 mm OD and 120 mm height are the two fastest reference dimensions. The related ML37 / MU37 models use 39588777 (130 mm OD × 250 mm H) — the size difference is substantial and the two are not interchangeable.

Materials

Item	Value / Note
Filter media	Imported wood-pulp filter paper (industry-standard grades such as HV or Ahlstrom)
Media weight	Approx. 130 g/m² (mid-range of the typical 100–150 g/m² for air filter paper)
Inner / outer support	Galvanized steel perforated cage, approx. 0.6 mm sheet, ≥45% open area
End caps	Metal end caps (galvanized steel) with polyurethane adhesive
Seal	NBR rubber seal, −30 to +100 °C, oil and heat resistant
Bonding	Polyurethane (PU) hot-melt adhesive

Operating limits

Parameter	Value / Note
Operating temperature	−10 to +100 °C
Relative humidity	≤80% RH, no condensation. Wood-pulp media loses strength and efficiency when wet; add upstream moisture removal in condensing conditions.
Bursting strength	Approx. 200–400 kPa (ISO 2758 paper burst test, typical range for air filter paper)
Collapse resistance	Element designed for differential pressure ≥10 kPa (approx. 50% safety margin over the 6.5 kPa alarm value)
Special features	No flame-retardant, anti-static or moisture-resistant ratings specified for this part number

Service life and storage

Parameter	Value / Note
Service life	Approx. 2000 hours
Practical replacement interval	Shorten to under 1000 hours in dusty, sandy or humid environments; always defer to the differential pressure alarm
Storage life	Approx. 2–3 years unopened, in dry and ventilated conditions. Moisture or direct sunlight will shorten this significantly.

Applicable standards

Item	Detail
Product standard	ISO 5011 — inlet air filters for internal combustion engines and compressors: performance testing by efficiency, intake resistance and dust holding capacity
Commonly cited test standards	ISO 2941 / 2942 / 2943 / 3723 / 3724 / 3968
Applicability note	The ISO 29xx / 37xx series are general test methods for hydraulic fluid power filter elements (collapse/burst, construction integrity, material compatibility, axial load, flow fatigue, pressure drop vs. flow). If a supplier can only provide hydraulic filter standards, request ISO 5011 data or the OEM specification sheet.

Installation and Maintenance

Single-person operation, approximately 20–30 minutes.

1. Shut down, isolate and depressurize. Press the stop button, switch off the main power and apply lockout/tagout. Open the receiver tank drain valve to release system pressure and wait until the separator tank gauge reads zero. Criterion: gauge at 0 with no residual air flow noise.
2. Locate and open the air filter housing. On the M37 the filter assembly is at the intake end. Release the housing clamp or end-cover bolts and remove the cover. Criterion: cover not deformed, clamp not seized. Free a seized clamp before proceeding.
3. Remove the old element and inspect it. Pull the element straight out and check dust distribution and media condition. Criterion: replace immediately if the media is torn, punctured, de-bonded from the end cap or the seal face is flattened — even if the service interval has not been reached. Black oily sludge on the outer surface indicates abnormal oil mist in the intake air; check the upstream environment.
4. Clean the housing thoroughly. 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 on the inner wall, seal face flat and free of debris.
5. Verify the new element. Compare against the old part: 270 mm OD, 120 mm height, intact face seal, undamaged media. Criterion: all three dimensions and the visual check must match. If any item does not match, 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 with the seal face clean and free of trapped material. Refit the cover and tighten the clamp or bolts evenly in a diagonal sequence. Criterion: even gap between cover and housing, no visible skew.
7. Start-up check. Restore power and run the compressor for 5–10 minutes. Criterion: no abnormal whistling or intake noise (unusual noise usually means the seal is not compressed or the element is not seated); differential pressure indicator in the green zone.

Non-negotiable rule: never start the compressor 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 in a short time.

FAQ

Are 99273906 and 39588777 interchangeable?
No. 39588777 is for the ML37 / MU37 models and measures 130 mm OD × 250 mm H. 99273906 is for the M37 and measures 270 mm OD × 120 mm H. The size difference is more than double and the parts cannot physically fit the same housing. Always cross-check by both machine model and part number.

How often should it be replaced?
Approximately 2000 hours under standard conditions, but this is not a fixed deadline. In high-dust environments (cement, foundry, woodworking, mining) shorten to under 1000 hours; in clean environments with light running hours it can be extended. The most reliable method is to follow the differential pressure indicator and replace at the alarm point.

What happens if it is not replaced?
Failure is a chain reaction with a clear cost. As dust loads the element, intake resistance rises and energy consumption increases by roughly 6.3% from 0 to 6 kPa. If the media tears or the seal fails, unfiltered air reaches the airend and contaminates the screw rotors, bearings, separator element, oil filter and lubricant — escalating repair cost from the price of one filter to an airend overhaul.

How do I know it needs replacing?
Three signals: the differential pressure indicator enters the alarm zone (approx. 6.0–6.5 kPa); visual inspection after shutdown shows the media fully covered in dust with no visible pleat pattern; or the compressor shows reduced capacity with rising current or energy consumption. 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 compressed air from the inside out only removes surface dust; deeply embedded fines remain. Back-pressure also easily fractures the paper fibers or distorts pleat spacing, creating invisible bypass paths. A cleaned element that looks fine is often functionally failed — the risk outweighs the saving.

What else should be checked when replacing the air filter?
Check the differential pressure indicator for correct reset operation, the intake hose for cracks or looseness, the housing seal for ageing, and the inlet valve for correct actuation. These parts work together with the filter; replacing the element without checking them often leads to repeat intake problems shortly after.

Is this a genuine OEM part?
99273906 is an Ingersoll Rand OEM part number. Always confirm by the part number itself — it is the only unambiguous identifier. Do not order based only on "fits M37" or visual similarity.

Do all M-series models use the same air filter?
No. Air filter specifications differ across the Ingersoll Rand M series: M22 uses 39588470 (130 mm OD), M37 uses 99273906 (270 mm OD), M55 uses 39708466 (278 mm OD), and ML37 uses 39588777. The same series does not mean the same element — verify model by model.

What is the most common installation mistake?
Two: compressing the cover with trapped material or an unseated element, causing a seal leak; and tightening cover bolts in a single-side sequence, causing uneven loading and skew. The correct method is to confirm seating, then tighten evenly in a diagonal cross pattern in stages.

Are there storage requirements for new elements?
Yes. Wood-pulp media swells and deforms when damp, reducing efficiency, and the metal cage can corrode. Store on indoor shelving in dry, ventilated conditions, off the floor and away from walls, water and oil. Use within 2–3 years unopened, following first-in-first-out. Long-term stockpiling is not advised.

Compatible Machine Models

No.	Model	Compressor capacity	Air filter part no.	Element OD × H
1	M37	6 m³/min @ 0.7 MPa	99273906	270 mm × 120 mm
2	M22	3 m³/min @ 0.7 MPa	39588470	130 mm × 151 mm
3	M55	10 m³/min @ 0.7 MPa	39708466	278 mm × 125 mm
4	ML37 / MU37	6 m³/min @ 0.7 MPa	39588777	130 mm × 250 mm
5	30S	3 m³/min @ 0.7 MPa	42855429	130 mm × 123 mm
6	50S	6 m³/min @ 0.7 MPa	42855411	216 mm × 318 mm
7	75S	10 m³/min @ 0.7 MPa	42855403	278 mm × 251 mm

How to read this table

• This page covers 99273906 for the M37, row 1. All other rows are for reference only, to help you rule out a wrong purchase.
• Row 4 (ML37 / MU37) and row 1 (M37) both deliver 6 m³/min, but the air filter part numbers and dimensions are completely different. Identical capacity does not mean a shared element — this is the most common confusion in the series.
• If your machine nameplate is not listed, send a photo of the nameplate and the full model number. We will cross-reference by part number before you order.

Note on machine generations

The Ingersoll Rand M37 was built in different production generations. The 99273906 described here belongs to the earlier M37 intake filter. Newer M37-75 series machines (covered by the SL/SM37-75KW parts manual) use a different part number system. If your unit is a recent build, confirm against the parts manual supplied with the machine, or contact us with the machine serial number. In practice the most reliable confirmation is still to read the part number from the old element itself.

Related Components

Seven components in the M37 intake and lubrication system are maintained on a similar cycle to the air filter. Listed below by location, function and inspection point. For specific part numbers, refer to the machine parts manual.

Component	Location	Function	Inspection point
Oil filter element	Main oil circuit, between cooler and airend	Removes wear debris and sludge from lubricant, protecting bearings and rotors	Replace together with the air filter; check housing seal face for oil seepage afterwards
Separator element	Inside the separator tank	Separates oil mist from compressed air and returns oil, controlling oil carryover	Check the oil return line for blockage during replacement (poor return directly causes high oil carryover)
Air filter differential pressure indicator	On the air filter assembly	Indicates element loading and replacement timing	Should reset correctly when pressed; a reading that never moves indicates failure and requires replacement
Coolant filter element	Coolant circuit, between cooler and filter	Keeps coolant clean, preventing scale and debris build-up	Replace together with the oil filter
Thermostatic control valve element	Between cooler and filter	Controls coolant flow through the cooler, maintaining airend operating temperature	If the machine runs cold or triggers high-temperature alarms, check the thermostatic valve first
Breather filter	On the separator tank	Balances tank pressure and prevents external dust entering the oil circuit	Inspect on the same cycle as the air filter; shorten the interval in dusty environments
Intake hose and housing seal	Between the air filter assembly and the airend	Ensures the intake path is leak-free with no unfiltered air bypass	Check for cracks, ageing and loose clamps — bypass leakage is as damaging as running with no element

Recommended replacement grouping: in high-dust sites, replace the air filter, oil filter and separator element together to avoid staggered maintenance intervals and repeated downtime. Schedule the coolant filter and thermostatic valve element on their own cycles.

For volume pricing, OEM/ODM private-label programs, packing options and lead times, send us your target quantity and machine model — we will respond with a quotation and datasheet.