Ingersoll Rand M37 Air Filter Element 99273906

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Product Overview

99273906 is the inlet air filter element for the Ingersoll Rand M37 rotary screw air compressor.

It installs inside the air filter housing at the compressor intake, upstream of the inlet valve, and serves as the first filtration barrier for the entire compressed air system. As the unit draws in ambient air, dust, grit, fibers, water mist, and oil mist are captured by the filter media before reaching the airend — surface filtration intercepts larger particles while depth filtration adsorbs finer contaminants. Only clean air is permitted into the rotor engagement zone.

The condition of this element directly affects airend service life. When unfiltered air enters the screw airend, hard particles accelerate rotor and bearing wear while contaminating the downstream separator element, oil filter, and lubricant, shortening all three in parallel. Severe clogging restricts intake volume, reducing discharge capacity and raising energy consumption; in extreme cases, oil carryover can lead to airend seizure. Replacing the air filter on schedule is therefore the lowest-cost protection measure for the airend.

Key Specifications

Item	Value
Part Number	99273906
Description	Air Filter Element
Applicable Model	Ingersoll Rand M37 rotary screw 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 per operating conditions)

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Basic Parameters

Parameter	Details
Part Number	99273906
Brand	Ingersoll Rand
Product Name	Air Filter Element
Product Category	Intake Filtration (Air Filter)
Applicable Model	M37 rotary 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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Technical Specifications

1. Filtration Performance (Core Metrics)

Parameter	Value / Description	Data Type
Filtration Rating	2–10 μm	Industry value (sources list 2–10, 3–12, 5–10, 10–15 μm; mainstream overlap 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 + dust holding capacity	Technical note
Dust Holding Capacity	Approx. 380 g	Estimated (effective filtration area 1.3 m² × typical wood pulp filter paper capacity 300 g/m²)
Beta Ratio (β)	Not applicable to air filter elements	Not applicable; see explanation below

About the Beta Ratio: The β value is a metric for hydraulic and lubricating oil filters, determined per ISO 16889 multi-pass testing, characterizing 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. If a β value appears in an air filter specification, it is typically miscopied from a hydraulic filter datasheet.

2. Flow and Resistance Parameters

Parameter	Value / Description	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 typical air filter range of 0.05–0.15 m/s)
Initial Pressure Drop	Approx. 0.5–1.0 kPa	Estimated (based on face velocity and wood pulp filter paper resistance characteristics)
Operating Differential Pressure Range	Approx. 1.0–6.0 kPa	Estimated (full range from new element initial resistance to alarm resistance)
Alarm Resistance / Final Resistance	6.0–6.5 kPa	Estimated (per unit air filter differential pressure indicator alarm setting; refer to complete machine)
Pressure Drop vs. Energy Consumption	Each 1 kPa increase in intake resistance raises unit energy consumption by approx. 1%	Estimated; calculation below

Quantitative Relationship Between Pressure Drop and Energy Consumption (Estimated)

Based on M37 discharge pressure 0.7 MPa (gauge) and atmospheric pressure 101.3 kPa, intake resistance increases 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 a filter element progresses from new to alarm condition (0 → 6 kPa), unit energy consumption rises by approximately 6%. For a 37 kW unit running 6,000 hours annually, this represents sustained excess power draw during the latter portion of element life. The cost of continued operation with a clogged element far exceeds the cost of the element itself — this is the engineering basis for the factory-set differential pressure alarm.

3. Structural Dimensions and Installation Parameters

Parameter	Value / Description	Data Type
Dimensions	Outer diameter 270 mm × height 120 mm	Multi-source consistent
Construction	Pleated (folded filter paper wound)	Industry value
Effective Filtration Area	Approx. 1.3 m²	Estimated (based on OD 270 / ID 200 / pleat depth 35 mm / approx. 154 pleats; approx. 1.7 m² if ID is 165 mm)
Number of Pleats	Approx. 150	Estimated
Pleat Spacing	Approx. 4.8 mm	Estimated (average circumference 738 mm ÷ 150 pleats)
Mounting Interface	End cap located, mates with M37 air filter assembly	Based on model compatibility
Sealing Method	Face seal (axial compression)	Estimated (common construction for this air filter type; refer to actual part)

Sourcing Note: When verifying replacement parts, outer diameter 270 mm and height 120 mm are the two most direct comparison dimensions. The ML37 / MU37 models in the same series use 39588777 (OD 130 mm × H 250 mm); the dimensional difference is substantial and the two are not interchangeable.

4. Material Composition

Parameter	Value / Description	Data Type
Filter Media	Imported wood pulp filter paper (industry commonly uses US HV or Korean Ahlstrom filter paper)	Industry value
Media Grammage	Approx. 130 g/m²	Estimated (mid-range of typical air filter paper 100–150 g/m²)
Inner/Outer Support	Galvanized steel perforated support, sheet thickness approx. 0.6 mm, open area ≥45%	Estimated (common practice for comparable products)
End Caps	Metal end caps (galvanized steel) + polyurethane adhesive	Estimated (no plastic end cap noted for this series)
Sealing Element	Nitrile rubber (NBR) seal ring	Estimated (common material for compressor intake components; oil and temperature resistant −30 to +100 °C)
Bonding Layer	Polyurethane (PU) hot-melt adhesive	Estimated (common process for bonding filter paper to end caps/support)

5. Operating Condition Tolerance

Parameter	Value / Description	Data Type
Operating Temperature	−10 to +100 °C	Industry value
Relative Humidity	≤80% RH, no condensation	Estimated (wood pulp filter paper loses strength and efficiency when damp; condensation conditions require upstream moisture removal)
Bursting Strength	Filter paper bursting strength approx. 200–400 kPa (per ISO 2758 paper bursting strength determination)	Estimated (typical range for air filter paper)
Collapse Pressure Resistance	Element design differential pressure resistance ≥10 kPa	Estimated (approx. 50% safety margin over 6.5 kPa alarm value)
Special Functions	No flame retardant, anti-static, or moisture-proof special ratings noted for this model	—

6. Service Life and Maintenance Parameters

Parameter	Value / Description	Data Type
Service Life	Approx. 2000 hours	Industry value (multi-source consistent)
Actual Replacement Interval	Reduce to under 1000 hours in dusty, sandy, or humid environments; follow differential pressure alarm	Engineering recommendation
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)

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 above ISO 29xx / 37xx series are actually general test methods for hydraulic fluid power filter elements (collapse/burst resistance, structural integrity, material compatibility, axial load, flow fatigue, pressure drop vs. flow characteristics). If a supplier can only provide hydraulic filter standards, request ISO 5011 or the OEM specification sheet.

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Standard Maintenance and Installation Steps

Unit: Single-person operation, approximate working time 20–30 minutes.

1. Shutdown, Power Isolation, and Depressurization
   Press the emergency stop or shutdown button, disconnect main power, and apply lockout/tagout. Open the air receiver drain valve to release system pressure and wait for the oil/air separator tank pressure gauge to read zero. Criterion: Gauge reads 0 and no residual airflow sound.

2. Locate and Open the Air Filter Housing
   The M37 filter assembly is located at the unit intake end. Loosen the housing clamp or end cover bolts and remove the end cover. Criterion: End cover not deformed, clamp not seized; if the clamp is seized, address it before removal.

3. Remove the Old Element and Inspect Its Condition
   Withdraw the old element vertically and observe dust distribution and filter paper condition. Criterion: If the filter paper shows damage, perforation, end cap debonding, or compressed sealing face, replace immediately even if the service interval has not been reached. If the outer surface is covered with black oil sludge, intake oil mist is abnormal and the upstream environment should be checked.

4. Thoroughly Clean the Housing Interior
   Wipe the housing inner walls and bottom with a lint-free cloth. Do not blow compressed air directly into the housing interior (this will drive 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 the old and new parts: outer diameter 270 mm, height 120 mm, face seal strip intact without gaps, filter paper undamaged. Criterion: All three dimensions and appearance conform; if any item does not match, do not install — re-verify the part number.

6. Install the New Element and Reassemble the End Cover
   Place the new element vertically into the housing, confirming it is fully seated at the bottom and the sealing face is properly aligned with no trapped material. Reinstall the end cover and tighten the clamp or bolts evenly in a diagonal sequence. Criterion: Uniform gap between end cover and housing, no visible misalignment.

7. Startup Check
   Restore power and run the unit for 5–10 minutes. Criterion: No abnormal whistling or intake airflow noise at the intake (abnormal noise usually indicates the seal is not compressed or the element is not seated); the air filter differential pressure indicator remains in the green zone.

Absolute Installation Rule: Never start the unit before the element is properly seated. Starting with no element or with an uncompressed seal allows unfiltered air directly into the airend, causing irreversible wear in a short time.

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Frequently Asked Questions

Are 99273906 and 39588777 interchangeable?
No. 39588777 is for ML37 / MU37 models with element outer diameter 130 mm and height 250 mm; 99273906 is for M37 with outer diameter 270 mm and height 120 mm. The dimensions differ by more than double and physically cannot fit the same housing. When ordering, verify both the model and the part number.

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

What happens if it is not replaced?
Failure propagates through the system and has a clear economic cost. As the element accumulates dust, intake resistance rises; based on compression ratio estimates, resistance increasing from 0 to 6 kPa raises unit energy consumption by approximately 6.3%. Once the filter paper 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 costs escalate from the price of one filter element to the level of an airend overhaul.

How do I know when to replace it?
Three signals: first, the differential pressure indicator enters the alarm zone (approx. 6.0–6.5 kPa); second, after shutdown, remove and visually inspect the element — the filter paper surface is completely covered with dust and the original pleat pattern is no longer visible; third, the unit shows reduced discharge capacity with increased current/energy consumption. Any one signal indicates replacement is due.

Can the element be cleaned and reused?
Not recommended. This type of element is a pleated paper filter designed as a single-use item. Back-blowing with compressed air from inside out only removes surface dust; deeply trapped fine particles cannot be removed. Additionally, back-blow pressure can easily cause filter paper fiber breakage or pleat deformation, creating invisible channels that allow unfiltered air to pass directly through. Continued use after cleaning represents a "looks clean, actually failed" condition with risks exceeding benefits.

What else should be checked when replacing the air filter?
Recommended simultaneous checks: whether the air filter differential pressure indicator is still responsive (can it return normally after pressing reset), whether the intake hose has cracks or is loose, whether the housing seal ring is aged, and whether the inlet valve operates normally. These components work in coordination with the air filter; replacing only the element without checking the surrounding parts can easily lead to recurring intake abnormalities in a short time.

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

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

What are the most error-prone steps during installation?
Two: first, compressing the end cover with trapped material on the sealing face or without full seating, causing seal leakage; second, tightening end cover bolts in a single-side sequence, causing uneven loading and misalignment. The correct method is to confirm seating, then tighten evenly in a diagonal cross pattern in multiple passes.

Are there storage requirements for new elements?
Yes. Filter paper expands and deforms when damp, reducing filtration efficiency, and the metal support corrodes when exposed to moisture. Store on indoor shelving in a dry, ventilated area, away from walls and floors, away from water and oil contamination. Use within 2–3 years in unopened condition. Follow first-in-first-out principles for unopened packaging; long-term stockpiling is not recommended.

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Compatible Models

No.	Model	Unit Discharge 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

• The product on this page, 99273906, corresponds to row 1, M37. Other rows are provided for cross-reference within the series to help you avoid mis-purchasing.
• 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 — same discharge capacity does not mean interchangeable filter elements. This is the most easily confused point in this series.
• If the model on your unit nameplate is not listed above, provide a photo of the unit nameplate and the complete model number. We will cross-reference by part number and confirm before you place an order.

Note on Model Generations

The Ingersoll Rand M37 exists in different production generations. The 99273906 described on this page belongs to the intake filter element for early M37 models. Newer M37-75 series units (corresponding to the SL/SM37-75KW operation and 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 method remains reading the part number directly from the old filter element body.

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Related Components

The M37 intake and lubrication system has 7 components maintained on the same cycle as the air filter. The following lists them by "location — function — inspection points." For specific part numbers, refer to the unit parts manual.

Component	Location	Function	Inspection Points
Oil Filter Element	Main oil circuit, between cooler and airend	Removes wear particles and sludge from lubricant, protecting bearings and rotors	Replace together with air filter; after replacement, check housing sealing face for oil seepage
Separator Element	Inside oil/air separator tank	Separates oil mist from compressed air and returns oil, controlling discharge oil content	During replacement, check oil return line for blockage (poor oil return directly causes excessive discharge oil content)
Air Filter Differential Pressure Indicator	On air filter assembly	Indicates element clogging level, prompting replacement timing	Should return normally after pressing reset; if the reading does not change over time, it has failed and should be replaced
Coolant Filter Element	Coolant circuit, between cooler and filter	Keeps coolant clean, preventing scale and wear particle deposits	Replace together with oil filter element
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 triggers high-temperature alarms, check the thermostatic valve first
Breather Filter	On oil/air separator tank	Balances tank pressure, preventing 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 Ring	Between air filter assembly and airend	Ensures intake path is leak-free with no unfiltered air bypass	Check for cracks, aging, loose clamps — bypass leakage is as harmful as installing no element at all

Recommended Replacement Package: In dusty sites, replace the air filter + oil filter + separator element together on the same cycle to avoid maintenance interval misalignment and repeated shutdowns from single-component replacement. Schedule the coolant filter and thermostatic valve element separately per their own intervals.