Ingersoll Rand 99273906 Air Filter Element for M37 Air Compressor

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1. Product Overview

99273906 is the intake air filter element for the Ingersoll Rand M37 screw air compressor. It installs inside the air filter housing at the compressor intake, upstream of the inlet valve, forming the first filtration barrier in the compressed-air system.

As the machine draws in ambient air, dust, grit, fibers, water mist, and oil mist are captured by the media before reaching the airend — surface filtration intercepts coarse particles, depth filtration adsorbs fine particles. Only clean air is allowed into the rotor mesh zone.

The condition of this element directly affects airend service life. Unfiltered air entering the screw airend accelerates rotor and bearing wear, and contaminates the downstream separator element, oil filter, and lubricant, shortening all three at the same time. Severe clogging reduces intake volume, lowering discharge capacity and raising energy consumption; in extreme cases oil carryover can cause airend seizure. Replacing the air filter element on schedule is therefore the lowest-cost protection measure for the airend.

Key specifications at a glance

Item	Value
Part number	99273906
Description	Air Filter Element
Application	Ingersoll Rand M37 screw air compressor
Unit discharge capacity	6 m³/min @ 0.7 MPa
Element outer diameter	270 mm
Element 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 resistance	6.0–6.5 kPa
Recommended replacement interval	approx. 2000 hours (adjust to operating conditions)

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2. Basic Parameters

Parameter	Details
Part number	99273906
Brand	Ingersoll Rand
Product name	Air Filter Element
Category	Intake filtration (air filter)
Fits models	M37 screw air compressor (see Section 6)
Unit discharge capacity	6 m³/min @ 0.7 MPa
Installation position	Inside intake air filter assembly, upstream of inlet valve
Replacement interval	approx. 2000 hours

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3. Technical Specifications

3.1 Filtration performance (core indicators)

Parameter	Value / note	Data type
Filtration rating	2–10 μm	Industry value (sources cite 2–10, 3–12, 5–10, 10–15 μm; mainstream overlap range taken)
Filtration efficiency	≥98% for particles ≥5 μm	Industry value
Filter class	HVAC filter classification (EN 779 G/M/F) does not apply. Air filter elements are characterized per ISO 5011 by filtration efficiency, intake resistance, and dust holding capacity.	Technical note
Dust holding capacity	approx. 380 g	Estimated (effective area 1.3 m² × typical wood-pulp media dust capacity 300 g/m²)
Beta ratio (β value)	Not applicable to air filter elements	Not applicable — see note below

About the β value: beta ratio is a hydraulic and lubricating oil filter metric determined per ISO 16889 multi-pass testing, describing filtration ratio at different particle sizes. Air filter elements are not characterized by β value; they are evaluated per ISO 5011 using filtration efficiency + intake resistance + dust holding capacity. A β value appearing in an air filter specification is usually copied in error from a hydraulic filter datasheet.

3.2 Flow and resistance parameters

Parameter	Value / note	Data type
Rated air flow	Matches M37 unit discharge 6 m³/min @ 0.7 MPa	Multi-source (unit parameters)
Filtration face velocity	approx. 0.077 m/s	Estimated (6 m³/min ÷ 1.3 m², within the normal 0.05–0.15 m/s air filter range)
Initial pressure drop	approx. 0.5–1.0 kPa	Estimated (based on face velocity and wood-pulp media resistance characteristics)
Operating differential pressure range	approx. 1.0–6.0 kPa	Estimated (full range from new-element initial resistance to alarm resistance)
Alarm / final resistance	6.0–6.5 kPa	Estimated (per unit air filter differential pressure indicator alarm setting; refer to the specific machine)
Pressure drop vs. energy consumption	Each 1 kPa rise in intake resistance increases unit energy consumption by approx. 1%	Estimated — calculation shown below

Quantitative relationship between pressure drop and energy consumption (estimated)

Based on M37 discharge pressure of 0.7 MPa (gauge) and atmospheric pressure of 101.3 kPa, intake resistance raises the compression ratio:

Intake resistance	Compression ratio	Relative energy increase vs. baseline
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%

Engineering implication: as an element progresses from new to alarm condition (0 → 6 kPa), unit energy consumption rises by roughly 6%. For a 37 kW unit running 6000 hours per year, this represents sustained excess power draw during the latter part of the element's life. The element cost saved by running a clogged filter is far outweighed by the extra electricity cost — this is the engineering rationale behind the factory-set differential pressure alarm.

3.3 Structural dimensions and installation parameters

Parameter	Value / note	Data type
Overall dimensions	270 mm OD × 120 mm H	Consistent across sources
Construction	Pleated (folded media wrap)	Industry value
Effective filtration area	approx. 1.3 m²	Estimated (based on 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 pleats	Estimated
Pleat spacing	approx. 4.8 mm	Estimated (average circumference 738 mm ÷ 150 pleats)
Mounting interface	End-cap located, matched to M37 air filter assembly	Based on model fitment
Sealing	Face seal (axial compression)	Estimated (common form for this air filter type; refer to actual part)

Procurement note: when verifying a replacement, 270 mm OD and 120 mm height are the two most direct dimensions to compare. The same-series ML37 / MU37 models use 39588777 (130 mm OD × 250 mm H) — the size difference is large and the two are not interchangeable.

3.4 Material composition

Parameter	Value / note	Data type
Media	Imported wood-pulp filter paper (industry-common US HV or Korean Ahlstrom media)	Industry value
Media basis weight	approx. 130 g/m²	Estimated (midpoint of typical 100–150 g/m² air filter paper range)
Inner/outer support	Galvanized steel perforated cage, approx. 0.6 mm thickness, open area ≥45%	Estimated (standard practice for comparable products)
End caps	Metal end caps (galvanized steel) + polyurethane adhesive	Estimated (no plastic end cap noted for this series)
Seal	NBR (nitrile rubber) sealing ring	Estimated (standard material for compressor intake parts, oil and temperature resistant −30 to +100 °C)
Bonding layer	Polyurethane (PU) hot-melt adhesive	Estimated (standard process for bonding media to end caps/cage)

3.5 Operating condition tolerances

Parameter	Value / note	Data type
Operating temperature	−10 to +100 °C	Industry value
Relative humidity	≤80% RH, no condensation	Estimated (wood-pulp media loses strength and efficiency when damp; condensation conditions require upstream moisture removal)
Bursting strength	Media bursting strength approx. 200–400 kPa (per ISO 2758 paper bursting strength test)	Estimated (normal air filter paper range)
Collapse resistance	Element designed for differential pressure ≥10 kPa	Estimated (approx. 50% safety margin over the 6.5 kPa alarm value)
Special functions	No flame-retardant, anti-static, or moisture-proof ratings noted for this model	—

3.6 Service life and maintenance parameters

Parameter	Value / note	Data type
Service life	approx. 2000 hours	Industry value (consistent across sources)
Actual replacement interval	Shorten to under 1000 hours in dusty, sandy, or humid environments; follow the differential pressure alarm	Engineering recommendation
Storage shelf life	approx. 2–3 years (unopened, dry, ventilated conditions)	Estimated (typical validity for filter paper and adhesives under controlled storage; moisture or direct sunlight significantly shortens this)

3.7 Applicable standards

Item	Details
Applicable product standard	ISO 5011 (inlet air cleaning equipment for internal combustion engines and compressors — performance testing), evaluated by filtration efficiency, intake resistance, and dust holding capacity
Commonly cited test standards	ISO 2941 / 2942 / 2943 / 3723 / 3724 / 3968
Standard applicability note	The ISO 29xx / 37xx series above are actually general test methods for hydraulic fluid power filter elements (collapse/burst pressure, structural integrity, material compatibility, axial load, flow fatigue, pressure drop vs. flow characteristics). When a supplier can only provide hydraulic filter standards, request ISO 5011 or the OEM specification sheet as a supplement.

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4. Standard Maintenance and Installation Steps

Single-person operation, approximately 20–30 minutes.

1. Shut down, disconnect power, and relieve pressure
   Press the emergency stop or shutdown button, disconnect the main power supply, and apply lockout/tagout. Open the receiver tank drain valve to release system pressure and wait for the separator tank pressure gauge to read zero. Criterion: gauge reads 0 and no residual air flow is audible.

2. Locate and open the air filter housing
   The M37 filter assembly is at the intake end of the unit. Loosen the housing clamp or end-cover bolts and remove the cover. Criterion: cover is not deformed and the clamp is not seized; if the clamp is seized, address it before removal.

3. Remove the old element and inspect its condition
   Pull the old element straight out and observe dust distribution and media condition. Criterion: if the media shows damage, perforation, end-cap debonding, or a flattened sealing face, replace it immediately even if the interval has not been reached. If the outer surface carries black oil sludge, intake oil mist is abnormal and the upstream environment should be checked.

4. Thoroughly clean the housing interior
   Wipe the inner walls and bottom with a lint-free cloth. Do not blow compressed air forcefully into the housing interior (this drives dust into the intake passage). Criterion: no loose dust on inner walls, sealing face flat and free of debris.

5. Verify the new element
   Compare old and new: 270 mm OD, 120 mm height, intact face seal with no gaps, undamaged media. Criterion: all three dimensions and appearance match; if any item does not match, do not install — recheck the part number.

6. Install the new element and refit the cover
   Place the new element vertically into the housing, confirming it seats fully at the bottom and the sealing face contacts without trapped material. Refit the cover and tighten the clamp or bolts evenly in a diagonal sequence. Criterion: even gap between cover and housing with no visible misalignment.

7. Start-up check
   Restore power and run the unit for 5–10 minutes. Criterion: no abnormal whistling or intake air noise at the intake (unusual noise usually means the seal is not compressed or the element is not seated); the air filter differential pressure indicator is in the green zone.

The one absolute rule: never start the unit before the element is properly seated. Starting with no element or an uncompressed seal allows completely unfiltered air into the airend and can cause irreversible wear in a short time.

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5. Frequently Asked Questions

Are 99273906 and 39588777 interchangeable?
No. 39588777 corresponds to ML37 / MU37 models with a 130 mm OD × 250 mm H element; 99273906 corresponds to M37 with a 270 mm OD × 120 mm H element. The size difference is more than double, so they physically cannot fit the same housing. Verify by both model and part number when ordering.

How often should it be replaced?
Approximately 2000 hours under standard conditions. This is not a hard deadline: in high-dust environments (cement, foundry, woodworking, mining sites) shorten to under 1000 hours; in clean environments with short running hours it may be extended appropriately. The most reliable method is to follow the air filter differential pressure indicator and replace at the alarm point.

What happens if it is not replaced?
Failure propagates through the chain, and the economics are clear. As dust accumulates, intake resistance rises; based on compression ratio calculations, resistance rising from 0 to 6 kPa increases unit energy consumption by about 6.3%. Once the media is damaged or the seal fails, unfiltered air enters the airend directly, and dust contaminates the screw rotors, bearings, separator element, oil filter, and lubricant simultaneously — repair cost escalates from the price of one element to the level of 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 surface fully covered with dust with no visible pleat pattern; or the unit shows reduced discharge capacity with rising current/energy consumption. Any one signal indicates replacement.

Can the element be cleaned and reused?
Not recommended. This is a pleated paper element designed as a single-use part. Back-blowing with compressed air from inside out removes only surface dust; deeply trapped fine particles cannot be cleared. Back-blow pressure also easily breaks media fibers or deforms pleat spacing, creating invisible channels that let unfiltered air pass through. Continued use after cleaning is a "looks clean, actually failed" condition with more risk than benefit.

What else should be checked when replacing the air filter?
Recommended: check that the differential pressure indicator is still responsive (does it return normally after reset), the intake hose for cracks or looseness, the housing seal for aging, and the inlet valve for correct operation. These parts work together with the air filter; replacing only the element without checking the surrounding components can quickly lead to recurring intake problems.

Is this element a genuine part?
The 99273906 described on this page is an Ingersoll Rand OEM part number. When ordering, rely on the part number itself — it is the only unambiguous identifier. Do not order based solely on "fits M37" or visual similarity.

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

What is the most error-prone step during installation?
Two things: first, compressing the cover with trapped material or an incompletely seated element, causing a poor seal and air leakage; second, tightening cover bolts in a one-sided sequence, causing uneven loading and cover misalignment. The correct method is to confirm seating, then tighten evenly in a diagonal cross pattern in stages.

Are there storage requirements for a new element?
Yes. Filter paper expands and deforms when damp, reducing filtration efficiency, and the metal cage corrodes with moisture. Store on indoor shelving in a dry, ventilated area, off the floor and away from walls, away from water and oil contamination. Use within 2–3 years in unopened packaging. Follow first-in-first-out principles and avoid long-term stockpiling.

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6. Compatible Models

No.	Model	Unit discharge capacity	Air filter part number	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

• The product on this page, 99273906, corresponds to row 1, M37. The other rows are provided as same-series comparisons to help you avoid mis-purchase.
• Row 4, ML37 / MU37, and row 1, M37, both have 6 m³/min discharge capacity, but the air filter part numbers and dimensions are completely different — equal discharge capacity does not mean an interchangeable element. This is the most commonly confused point in this series.
• If your unit's nameplate model is not listed above, provide a photo of the unit nameplate and the complete model number. We will reverse-look-up by part number to confirm before you order.

Model generation note

The Ingersoll Rand M37 exists in different production generations. The 99273906 described here is the intake filter element for earlier M37 models. Newer M37-75 series units (corresponding to the SL/SM37-75KW operation parts manual) use a different part number system in their parts manuals. If your unit is a recent model, verify against the parts manual supplied with the machine, or contact us to confirm by unit serial number. In practice, the most reliable confirmation is still to read the part number from the old element itself.

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7. Related Components

The M37 intake and lubrication system has 7 components maintained on the same cycle as the air filter. They are listed below by location, function, and inspection point. For specific part numbers, refer to the unit 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 air filter; check housing sealing face for oil seepage after replacement
Separator element	Inside separator tank	Separates oil mist from compressed air and returns oil, controlling oil carryover	Check the oil return line for blockage during replacement (poor oil return directly causes excessive oil carryover)
Air filter differential pressure indicator	On air filter assembly	Indicates element clogging level and signals replacement timing	Should return normally after reset; if the reading never moves, it has failed and should be replaced
Coolant filter element	Coolant circuit, between cooler and filter	Keeps coolant clean, preventing scale and wear debris deposits	Replace together with oil filter
Thermostatic control valve element	Between cooler and filter	Controls whether coolant passes through the cooler, maintaining airend operating temperature	If the unit runs cold long-term or gives high-temperature alarms, check the thermostatic valve first
Breather filter	On separator tank	Balances tank pressure and prevents external dust from 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 air filter assembly and airend	Ensures no leakage or unfiltered air bypass in the intake path	Check for cracks, aging, and loose clamps — bypass leakage is as harmful as running without an element

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