MD3 Series Port Sizes 1/4" to 1/2"; Flow to 92 scfm (2605 l/min)

Actual product may differ from above image. Product details should be verified before purchase.

Modular or inline mounting
Polycarbonate plastic bowl with steel shatterguard, orl metal bowl with sight glass
Optional differential pressure gauge
Automatic drain, manual drain, automatic external drain, or electronic drain

Air Preparation Filters MD3 Series Product Overview

The MD3 Series of Air Preparation Filters sets the standard for dependable air filtration. These filters are engineered to deliver exceptional performance with filtration options including 5- and 40-micron levels for efficient removal of particulate matter. For precision filtration, our Coalescing Filters come in 0.3- and 0.01-micron options, ensuring the cleanest air possible. With the inclusion of Oil Vapor Removal (Adsorbing) Filters, you can trust in the removal of oil and hydrocarbon vapors. The range of Filter Drains, which includes manual, automatic, internal float, and automatic external drains, simplifies maintenance. Offering both modular and in-line mounting options, these filters adapt to your specific space and system requirements. You can select from either metal or High Strength polycarbonate bowl materials to match the environmental conditions. To provide comprehensive control and monitoring of your filtration systems, we offer several Differential Gauge options. The MD3 Series Air Preparation Filters are your trusted choice for top-tier air filtration.

Please refer to the side and below for links to easily navigate and Air Preparation Filters MD3 Series catalogs, installation instructions, and technical data. Additionally, you have the option to filter through all available options to discover the Air Preparation Filters MD3 Series variant that meets your requirements.

Series Overview ❯

Product Overview

The ROSS Controls MD3 Series is a family of modular and inline air preparation filters engineered for port sizes 1/4 inch through 1/2 inch (NPT or G/BSPP) with maximum particulate filter flow of 92 scfm (2,605 l/min). The MD3 represents ROSS Controls' advanced modular filter design in the 1/4-to-1/2-inch port size range, offering higher flow capacity than the Mid-Size Series while adding expanded configuration options including diaphragm-type regulator compatibility, integrated L-O-X lockout valve assembly, and comprehensive clean air packages.

The MD3 Series encompasses particulate filters, coalescing filters, oil vapor removal (adsorbing) filters, and clean air packages that combine all three filtration stages. Particulate filters use 5-micron polyethylene (standard) or sintered bronze elements (5, 20, 40 micron options). Coalescing filter variants with borosilicate glass fiber elements remove oil aerosols to 0.3-micron or 0.01-micron levels. Adsorbing filter elements use activated carbon to capture hydrocarbon vapors. Clean air packages integrate filter, coalescing, and optional adsorbing stages in a single modular assembly.

The MD3 bowl uses a high-strength polycarbonate with a nylon shatterguard (5.1-oz / 151-ml capacity) or aluminum with a clear nylon sight glass (6-oz / 177-ml capacity). Drain options include manual drain, internal float drain, and a less-drain fitting option (1/4 NPT female). The modular design enables L-O-X lockout valve integration either on the inlet or outlet side with standard or EEZ-ON soft-start function, supporting OSHA lockout/tagout requirements at the point of air preparation.

For systems engineers specifying air preparation for 1/4-to-1/2-inch port pneumatic circuits where higher flow, advanced filtration stages, or integrated energy isolation is required, the MD3 Series delivers the most complete catalog-standard solution in the ROSS FRL product line at this port size range.

Key Engineering Features

High-Flow Design to 92 scfm - Exceeds Mid-Size Series capacity by 23% at the same port sizes, reducing pressure drop across the filter stage and enabling use on higher-demand pneumatic circuits without upsizing to larger port hardware.
Diaphragm-Type Regulator Compatibility - MD3 Series filter/regulator models support diaphragm-type pressure regulators, which provide more precise outlet pressure control under varying flow conditions compared to piston-type regulators, critical for sensitive pneumatic circuits.
L-O-X Lockout Valve Integration - The MD3 can be ordered with integral L-O-X lockout valves on the inlet or outlet side, or with L-O-X plus EEZ-ON soft-start function, creating a combined filtration and energy isolation assembly that satisfies OSHA lockout/tagout requirements at the point of air use.
Clean Air Package Option - MD3 clean air packages combine a 5-micron particulate filter, 0.3-micron or 0.01-micron coalescing filter, and optional activated carbon adsorbing filter in a single modular assembly, providing ISO 8573-1 Class 1 quality air in a compact configuration.
Polycarbonate Bowl with Nylon Shatterguard - Standard polycarbonate bowl (5.1-oz / 151-ml) includes a nylon shatterguard for personnel protection. The transparent bowl allows visual condensate monitoring.
Aluminum Bowl with Sight Glass - Aluminum metal bowl (6-oz / 177-ml) extends upper operating temperature to 175 F (79 C) and maximum inlet pressure to 250 psig (17 bar) for manual drain models, the highest pressure rating in the MD3 size class.
Multiple Drain Options - Manual drain, internal float drain, and less-drain fitting (1/4 NPT female for remote drain connection) options accommodate diverse installation requirements including remote condensate management and high-volume automatic drainage.
Differential Pressure Gauge Options - Multiple gauge options in ranges from 0-50 psig through 0-200 psig, including versions with panel mount nut, allow matching gauge range to application operating pressure and enable condition-based element replacement.
Stainless Steel Option - MD3 Series filter/regulators with L-O-X lockout valves are available in stainless steel construction for food processing, pharmaceutical, and corrosion-resistant applications.
NPT and G (BSPP) Port Options - Both NPT and G (BSPP) thread types are standard catalog options, supporting installations on North American and international machine designs.
Reverse Flow Configuration - Reverse flow models available for applications where supply and exhaust directions are inverted relative to standard configuration, enabling installation flexibility in complex plumbing arrangements.

Technical Specifications

General Specifications

Parameter	Specification
Series	MD3 Series (ROSS FRL)
Product Type	Modular and Inline Air Preparation Filters (particulate, coalescing, adsorbing, clean air package)
Port Sizes	1/4", 3/8", 1/2" (NPT or G/BSPP)
Maximum Flow (Particulate Filter)	92 scfm (2,605 l/min)
Maximum Flow (Coalescing / Clean Air Package)	125 scfm (3,540 l/min)
Filtration Levels	5 µm (polyethylene or sintered bronze); 20 µm and 40 µm (sintered bronze); 0.3 µm and 0.01 µm (borosilicate glass fiber, coalescing); Activated carbon (adsorbing)
Bowl Capacity	Polycarbonate 5.1 oz (151 ml); Aluminum 6 oz (177 ml); Extended metal 10 oz (300 ml)
Bowl Materials	Polycarbonate with nylon shatterguard; Aluminum with nylon sight glass
Drain Types	Manual; Internal float; Less drain (1/4 NPT female fitting)
Mounting	Modular (manifold/port kit) or Inline
Port Thread Types	NPTF (NPT); G (BSPP)
Flow Media	Compressed air
Body Material	Die-cast zinc
Seal Material	Nitrile
Standard Particulate Element	5 µm Polyethylene (Part No. R-A60F-03PE5)
Pressure Gauge Range	0 to 60 psig (0 to 4 bar) or 0 to 200 psig (0 to 14 bar); 1/4 NPT gauge ports front and rear

Temperature Ratings

Temperature ratings are determined by bowl material selection. Polycarbonate with nylon shatterguard has a lower upper limit; aluminum bowl permits higher temperature operation.

Configuration	Ambient Temperature	Media Temperature
Polycarbonate Bowl, Auto Drain (30-150 psig)	40 to 125 F (4 to 52 C)	40 to 125 F (4 to 52 C)
Aluminum Bowl, Auto Drain (30-200 psig)	40 to 175 F (4 to 79 C)	40 to 175 F (4 to 80 C)
Polycarbonate Bowl, Manual Drain (0-150 psig)	40 to 125 F (4 to 52 C)	40 to 125 F (4 to 52 C)
Aluminum Bowl, Manual Drain (0-250 psig)	40 to 175 F (4 to 79 C)	40 to 175 F (4 to 80 C)

Important: The manual drain aluminum bowl is rated to 250 psig (17 bar), the highest inlet pressure in the MD3 series. Do not exceed bowl-specific pressure ratings. Automatic drain models require minimum 30 psig inlet pressure for float mechanism operation.

Flow Performance Data

Flow performance at 100 psig inlet pressure, new element. Coalescing and clean air package stage flows may differ from particulate-only values.

Port Size	Filter Type	Max Flow	Bowl Capacity
1/4"	Particulate (5 µm)	92 scfm (2,605 l/min)	5.1 oz poly / 6 oz alum
3/8"	Particulate (5 µm)	92 scfm (2,605 l/min)	5.1 oz poly / 6 oz alum
1/2"	Particulate (5 µm)	92 scfm (2,605 l/min)	5.1 oz poly / 6 oz alum
1/4" to 1/2"	Coalescing (0.3/0.01 µm) / Clean Air Package	125 scfm (3,540 l/min)	5.1/6/10 oz

Certifications & Compliance

Certification/Standard	Detail
Thread Standards	NPT (NPTF) per ANSI B1.20.1; G (BSPP) per ISO 228. Both available as standard catalog models.
Material Compliance	Nitrile seals, sintered bronze and polyethylene filter elements, borosilicate glass fiber coalescing elements, and activated carbon adsorbing elements are compatible with compressed air service.
Pressure Vessel Design	Polycarbonate bowl rated to 150 psig (10 bar); aluminum bowl manual drain rated to 250 psig (17 bar). Units designed and tested per manufacturer specifications.
ISO Air Quality	5-micron particulate filter addresses ISO 8573-1 Class 3-5 particulate. 0.3-micron coalescing element: Class 2 oil. 0.01-micron coalescing element: Class 1 oil. Activated carbon adsorber addresses hydrocarbon vapor per ISO 8573-1 Class 1-2.
OSHA Lockout/Tagout	MD3 units with L-O-X lockout valve integration provide padlockable energy isolation at the air preparation stage, supporting OSHA 29 CFR 1910.147 lockout/tagout compliance.

Typical Applications & Industries

Industrial Automation and Robotics

Central air preparation stations for robot cells and automated assembly systems where 92 scfm capacity at 1/2-inch supply ports serves multiple robots and end-effector pneumatics without excessive pressure drop.
Clean air supply for pneumatic servo actuators, proportional valve circuits, and precision motion systems where oil-free air from the MD3 coalescing stage prevents valve spool sticking and servo valve contamination.
L-O-X lockout integration at robot cell air preparation stations for OSHA-compliant energy isolation during maintenance, tooling changes, and robot programming activities.
Air preparation for pneumatic grippers, rotary actuators, and multi-axis actuator systems in high-cycle assembly automation where consistent air quality reduces maintenance intervals.

Machine Tools and Metalworking

Air preparation for CNC machining center pneumatics including part clamping, tool changer, spindle air purge, and coolant system actuators at 1/2-inch supply port size.
Clean air preparation (coalescing stage) for air-bearing spindle supply, precision measurement systems, and coordinate measuring machine (CMM) pneumatics where oil contamination causes bearing failure.
Compressed air supply for pneumatic tombstone fixtures, rotary indexers, and pallet changers on horizontal machining centers requiring clean, regulated air at 60 to 100 psig.
Air preparation for electrical discharge machining (EDM) dielectric pump pneumatics and tool change systems where filtered compressed air protects precision hydraulic and pneumatic components.

Process and Specialty Gas Applications

Instrument air preparation at 1/2-inch supply manifolds in process plants where MD3 filters with diaphragm regulators supply multiple pneumatic valve positioners and instrument air headers.
Clean air supply for purge-and-pressurization systems in hazardous area enclosures (NEMA 4X, ATEX) where oil-free, particulate-free supply air prevents instrument contamination and preserves hazardous area integrity.
Compressed air preparation ahead of air-operated diaphragm pumps in chemical processing where 5-micron filtration protects pump actuator mechanisms from scale and particulate damage.
Coalescing filter (0.01-micron) application in food and pharmaceutical grade air systems as part of a clean air package delivering ISO 8573-1 Class 1 oil and particulate quality.

Energy Isolation and Safety-Compliant Applications

Combined filtration and lockout assembly at machine air preparation points for facilities requiring OSHA 29 CFR 1910.147 lockout/tagout compliance with permanent padlockable energy isolation hardware.
MD3 with L-O-X plus EEZ-ON (soft-start) for applications requiring both safe energy isolation and controlled re-pressurization after lockout, protecting actuators and cylinders from pressure surge on startup.
Air preparation stations on die change carts, mold change systems, and tooling setups where portable lockout valve integration on the MD3 assembly provides both air conditioning and portable energy isolation.
Stainless steel MD3 filter/regulator with L-O-X lockout for food processing, pharmaceutical, and washdown environments requiring corrosion-resistant construction and OSHA-compliant energy isolation.

Ordering and Model Number Configuration

The ROSS MD3 Series uses a structured alphanumeric configuration code system. Filter type, port size, bowl material, drain type, gauge range, lockout valve options, and thread type are each specified by a position code in the model number string.

MD3 SERIES HOW TO ORDER (Filters):

MD3 50P C M 2 2 A

| |

| | A = NPT | B = BSPP/G threads

| | 2 = Polycarbonate bowl

| | Y = Aluminum bowl

| 2 = 1/4" port | 3 = 3/8" port | 4 = 1/2" port

| M = Manual Drain | F = Float Drain | L = Less drain fitting

C = Gauge 0-200 psig | D = Without gauge (with panel nut)

B = Gauge 0-60 psig | F = Gauge 0-200 psig (with panel nut)

50P = Polycarbonate bowl / 50M = Aluminum bowl

50E = Extended aluminum bowl

MD3 = Series designation

LOCKOUT VALVE INTEGRATION CODES:

Add L-O-X® prefix options: 2 = L-O-X inlet | 3 = L-O-X EEZ-ON inlet | 4 = L-O-X outlet

REPLACEMENT ELEMENTS:

R-A60F-03PE5 = 5 µm Polyethylene

R-A60F-03E5 = 5 µm Sintered Bronze

R-A60F-03E4 = 20 µm Sintered Bronze

R-A60F-03E3 = 40 µm Sintered Bronze

For G (BSPP) threads, specify B in the thread position of the configuration code.

L-O-X lockout valve integration requires specification of inlet or outlet side and standard or EEZ-ON (soft-start) function in the order code.

Stainless steel MD3 filter/regulator with L-O-X is available; contact ROSS Controls for model number.

Clean air package (filter + coalescing + optional adsorbing) uses the MD3 CAP order code series; consult the ROSS FRL catalog for full configuration details.

Reverse flow models available; consult ROSS Controls for applicable model number.

Accessories

Replacement Filter Elements

ROSS replacement elements for MD3 Series filters. Sintered bronze elements are available in 5, 20, and 40 micron ratings. Coalescing and adsorbing elements use separate part numbers.

Element Rating	Material	Model Number
5 µm Polyethylene (standard)	Polyethylene	R-A60F-03PE5
5 µm Sintered Bronze	Sintered Bronze	R-A60F-03E5
20 µm Sintered Bronze	Sintered Bronze	R-A60F-03E4
40 µm Sintered Bronze	Sintered Bronze	R-A60F-03E3

L-O-X Lockout Valves

The MD3 Series can be ordered with integrated L-O-X lockout valves on the inlet or outlet side. L-O-X lockout valves are padlockable for OSHA-compliant energy isolation. EEZ-ON (soft-start) option provides controlled re-pressurization after lockout release. Contact ROSS Controls for lockout valve model number selection.

Differential Pressure Gauges

Multiple differential pressure gauge ranges available (0-60 psig and 0-200 psig) with or without panel mount nuts. Gauges indicate element loading and alert when element replacement is required.

Frequently Asked Questions (FAQ)

Q: How does the MD3 Series differ from the Mid-Size Series?

A: Both cover 1/4 to 1/2 port sizes, but the MD3 provides higher flow (92 scfm vs. 75 scfm), supports diaphragm-type regulator configurations, offers more drain options including the less-drain fitting for remote condensate management, integrates L-O-X lockout valves in a single assembly, and provides a wider range of differential gauge options. The MD3 is the preferred choice for new machine designs; the Mid-Size is typically specified for OEM continuity with existing machine designs.

Q: What is the maximum inlet pressure for MD3 Series units?

A: Maximum inlet pressure depends on bowl material and drain type. Polycarbonate bowl models with automatic drain are rated to 150 psig (10 bar). Aluminum bowl with automatic drain is rated to 200 psig (14 bar). Aluminum bowl with manual drain is rated to 250 psig (17 bar), the highest pressure rating in the MD3 size range. Automatic drain models require a minimum inlet pressure of 30 psig.

Q: What filtration levels are available in the MD3 Series?

A: Particulate filter models offer 5-micron polyethylene (standard), 5-micron sintered bronze, 20-micron sintered bronze, and 40-micron sintered bronze elements. Coalescing variants provide 0.3-micron (standard) and 0.01-micron borosilicate glass fiber elements. Adsorbing filter variants use activated carbon for hydrocarbon vapor removal. Clean air packages combine two or three of these stages in a single modular assembly.

Q: Can the MD3 Series integrate a lockout valve for OSHA compliance?

A: Yes. MD3 filters can be ordered with integral L-O-X lockout valves on the inlet side (lockout upstream of filter), outlet side (lockout downstream), or with L-O-X plus EEZ-ON soft-start on the inlet side. This creates a combined air preparation and energy isolation assembly that satisfies OSHA 29 CFR 1910.147 lockout/tagout requirements with padlockable control at the point of air use.

Q: What is a clean air package?

A: A clean air package is a pre-configured modular assembly combining a 5-micron particulate filter, 0.3-micron or 0.01-micron coalescing filter, and optionally an activated carbon adsorbing filter stage, all connected through a common manifold with a single inlet and outlet port. MD3 clean air packages deliver ISO 8573-1 Class 1 quality compressed air at 1/4-to-1/2-inch port sizes in a compact assembly that eliminates the need to individually select, purchase, and connect three separate filter stages.

Q: What is the difference between the standard drain and the less-drain fitting option?

A: The standard automatic or manual drain option drains condensate from the bowl to atmosphere at the filter location. The less-drain fitting option provides a 1/4 NPT female fitting in place of the internal drain mechanism, allowing connection of a remote condensate drain line to a central collection point. This is preferred in installations where floor drainage at the filter location is impractical or where centralized condensate management is required.

Q: What is the bowl capacity of the MD3 Series?

A: The polycarbonate bowl holds 5.1 oz (151 ml) and the standard aluminum metal bowl holds 6 oz (177 ml). An extended aluminum bowl (10 oz / 300 ml) is available for coalescing filter variants and for applications with high condensate generation rates. The MD3 bowl capacity exceeds that of the Mid-Size Series, reducing drain frequency.

Q: Does the MD3 Series support reverse flow installation?

A: Yes. Reverse flow models are available for the MD3 Series. In reverse flow configuration, the filter inlet and outlet are transposed relative to the standard direction. This supports installation flexibility in complex plumbing arrangements. Note that L-O-X lockout valve integration on the inlet side of reverse flow models requires the reverse flow option to be specified simultaneously.

Q: Are stainless steel MD3 units available?

A: Yes. Stainless steel MD3 filter/regulator assemblies with L-O-X lockout valves are available, specifically for food processing, pharmaceutical, and corrosion-resistant applications where stainless steel contact surfaces and corrosion-resistant housing materials are required.

Q: What is the gauge port thread size and location?

A: The MD3 Series filter/regulators include 1/4 NPT gauge ports on both the front and rear face of the unit. Gauge ranges available include 0 to 60 psig (0 to 4 bar) and 0 to 200 psig (0 to 14 bar). Panel mount nut options are available for mounting the gauge through a panel cutout.

Q: What replacement element is standard for the MD3 particulate filter?

A: The standard 5-micron polyethylene replacement element is R-A60F-03PE5. Sintered bronze options are R-A60F-03E5 (5 micron), R-A60F-03E4 (20 micron), and R-A60F-03E3 (40 micron). These element part numbers are specific to the MD3 and are not interchangeable with Bantam, Miniature, Mid-Size, or Full-Size Series elements.

Q: What is the minimum operating pressure for the MD3 automatic drain?

A: Automatic drain (float drain) models require a minimum inlet pressure of 30 psig (2 bar) for the float mechanism to seat and create a liquid seal. Operation below 30 psig will cause the float to open continuously, passing air through the drain circuit. For systems operating below 30 psig, specify the manual drain or less-drain fitting option.

Installation & Maintenance Guidelines

Mount modular MD3 assemblies with the bowl pointing down. Vertical orientation is required for proper automatic float drain operation and condensate collection.
Install an isolation shutoff valve upstream to enable element replacement and service without system depressurization.
Always install a 5-micron particulate filter upstream of coalescing filter stages. Liquid water entering coalescing glass fiber elements saturates the media and significantly reduces coalescing efficiency.
For L-O-X lockout valve integration, verify padlock shackle diameter compatibility with the facility's standard lockout padlocks before installation. ROSS L-O-X valves accept standard padlock shackles.
The MD3 automatic float drain requires minimum 30 psig inlet pressure. Verify supply pressure before commissioning automatic drain models.
For less-drain fitting models, connect a drain line to the 1/4 NPT female fitting and route to an appropriate condensate collection or disposal point. Verify drain line slope allows gravity flow without back-pressure at the drain fitting.
Differential gauge: install with the high-pressure port connected to the filter inlet side and the low-pressure port to the outlet side to correctly indicate element pressure drop. Replace element when indicated differential pressure reaches 10 psig (0.7 bar).
Verify all module-to-module port kit seals are properly seated when assembling MD3 modular stations. Finger-tighten modules before torquing port kit hardware.
Do not exceed bowl pressure ratings. Polycarbonate bowl maximum is 150 psig; aluminum bowl maximum is 200 psig (auto drain) or 250 psig (manual drain).
For stainless steel units in washdown environments, verify that the lockout valve padlock and associated hardware are also corrosion-resistant before installation.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all MD3 Series products, covering defects in material and workmanship from the date of purchase.

Global technical support is available through ROSS Controls offices in the USA (headquarters in Ferndale, Michigan), Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

Contact ROSS Controls USA at (800) 438-7677 or visit rosscontrols.com for product configuration assistance, technical support, and distributor locator services.

For complete dimensional drawings, flow curves, and ordering configuration details, visit the ROSS Controls MD3 Series product page at rosscontrols.com or download the ROSS FRL catalog.

Download Catalog: https://www.rosscontrols.com/en/series/72-md3-series