MD4 Series Port Sizes 3/8" to 3/4"; Flow to 205 scfm (5806 l/min)

Product Overview

The ROSS Controls MD4 Series is the highest-flow Filter/Regulator and Lubricator combo in this range, delivering air preparation for pneumatic systems operating at port sizes from 3/8" to 3/4" with a maximum flow capacity of 205 scfm (5806 l/min). This flow capacity makes the MD4 Series appropriate for large-scale manufacturing lines, heavy industrial equipment, and high-demand production systems where the lower-flow FRL combos cannot satisfy aggregate pneumatic consumption.

The MD4 Series filter section offers three bowl material options to match environmental conditions: polycarbonate plastic with steel shatterguard for visual condensate monitoring with impact protection in standard industrial environments, aluminum with clear sight glass for extended pressure and temperature capability, and extended aluminum with sight glass for applications requiring larger oil reservoir capacity with enhanced durability. Condensate management options include manual drain, automatic (float) drain, and electronic drain for fully automated operation in lights-out or remote installations.

The diaphragm-type regulator provides precise, low-hysteresis pressure control to maintain stable output pressure across the full 205 scfm flow range. Two gauge ports are provided as standard to allow installation flexibility in cramped panel or machine layouts. Both self-relieving and non-relieving regulator configurations are available to match system requirements.

The sight-feed lubricator delivers visible oil delivery into the compressed air stream, allowing operators to confirm lubrication at a glance during routine production checks. The modular mounting design of the MD4 Series allows the assembly to be expanded or reconfigured without disconnecting the pipe work, and individual sections can be serviced independently to minimize production disruption during maintenance.

Key Engineering Features

• High Flow Capacity to 205 scfm - Rated for 205 scfm (5806 l/min) at port sizes through 3/4", the highest capacity in the ROSS FRL combo lineup at this port range, covering high-demand production and heavy industrial applications.
• Diaphragm-Type Regulator with Dual Gauge Ports - Low-hysteresis diaphragm regulator maintains stable output pressure across varying high-flow demand; two gauge ports allow right-hand or left-hand gauge orientation to suit installation constraints.
• Sight-Feed Lubricator - Transparent sight dome provides direct visual confirmation of oil delivery, enabling operators to verify lubrication is occurring and adjust the feed rate during normal production operation.
• Three Bowl Options - Polycarbonate with steel shatterguard, aluminum with clear sight glass, or extended aluminum with sight glass, covering standard through high-temperature and high-pressure environments with optional increased oil capacity.
• Three Drain Options - Manual drain, automatic (float) drain, and electronic drain provide complete flexibility for any installation condition from manually serviced to fully automated unattended operation.
• Modular Mounting - Modular design allows individual sections to be serviced, replaced, or reconfigured without removing the assembly from the compressed air piping, minimizing production downtime during maintenance.
• Self-Relieving or Non-Relieving Regulator - Self-relieving vents excess downstream pressure when the set point is reduced; non-relieving retains downstream pressure for applications where atmospheric exhaust is not permitted.
• Standard Pressure Gauge - Integral pressure gauge on the regulator body provides continuous monitoring of regulated output pressure. Dual gauge ports allow installation on either side of the assembly.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

High-Volume Manufacturing and Assembly

• Main air preparation header stations on high-volume automotive assembly lines supplying multiple pneumatic tools, fixtures, and actuators from a single 3/4" FRL rated to 205 scfm.
• Transfer line and flexible manufacturing system air drops where aggregate pneumatic demand from multiple stations exceeds the capacity of mid-size FRL combos.
• High-cycle stamping and forging press control circuits with pneumatic clutch-brake systems requiring high instantaneous flow at 3/4" supply connections.
• Welding robot work cell air preparation with 3/4" supply connections powering multiple pneumatic positioners, part clamps, and tool change actuators simultaneously.

Heavy Machine Tool and Metalworking

• Large-format machining centers including horizontal boring mills, gantry-type machines, and 5-axis machining centers with multiple pneumatic consumers requiring high-flow air preparation at 3/4" ports.
• Roll-forming, tube-bending, and profile-extrusion equipment with pneumatic clamping and feed systems demanding 200 scfm class air preparation.
• Heat treatment and quench line pneumatic controls where aluminum bowl construction handles elevated ambient temperatures near furnaces and quench tanks.

Process and Energy Industries

• Natural gas compressor station auxiliary pneumatic systems with high aggregate flow requirements, where the electronic drain option provides automated condensate removal without operator attendance.
• Petrochemical process plant control air distribution headers supplying large numbers of pneumatic field devices from a central modular FRL station with diaphragm regulator for precise instrument air conditioning.
• Power plant auxiliary instrument air systems requiring stable high-flow air preparation for turbine and boiler control actuators.

Mining and Mineral Processing

• Mineral processing plant pneumatic conveying and valve actuation systems where 3/4" supply connections and 205 scfm capacity handle high-volume process actuator demands.
• Underground mining equipment compressed air preparation for drilling, bolting, and material handling pneumatics in remote locations where the extended aluminum bowl provides maximum oil capacity between service intervals.
• Crusher and mill control pneumatic systems requiring reliable high-flow air preparation with automatic drain for continuous operation in wet, dusty environments.

Shipbuilding and Offshore

• Shipyard assembly pneumatic systems with multiple air tools, plasma cutting supports, and material handling equipment requiring 3/4" FRL stations rated to 205 scfm.
• Offshore platform process air preparation for pneumatic valve actuators and instrumentation where the aluminum bowl extended capacity and electronic drain minimize maintenance frequency.

Food, Beverage, and Pharmaceutical

• High-throughput filling and packaging lines in food and beverage manufacturing with aggregate pneumatic demand exceeding 140 scfm at 3/4" main supply connections.
• Pharmaceutical batch processing equipment with large pneumatic actuator populations requiring central high-flow air preparation with stable diaphragm regulator pressure control.
• Brewery and beverage carbonation systems where clean, regulated, lubricated air at high flow rates supports filling, capping, and palletizing pneumatic circuits.

Ordering and Model Number Configuration

The ROSS MD4 Series FRL combo is configured by selecting port size, bowl material, drain type, and regulator function. Contact ROSS Controls at (800) 438-7677 or visit rosscontrols.com for complete model number generation and application support.

Specify port size, bowl material, drain type (manual, automatic float, or electronic), and regulator function (self-relieving or non-relieving) when ordering.

NPT thread is standard. G (BSPP) thread availability should be confirmed with ROSS Controls at time of order.

Electronic drain option requires a 24 VDC or 110 VAC power supply for the drain solenoid. Confirm power supply compatibility before ordering.

Extended aluminum lubricator bowl provides larger oil capacity for extended service intervals, reducing refill frequency in high-production environments.

For applications not requiring lubrication, refer to the ROSS Controls MD4 Series filter/regulator.

Accessories

Mounting Brackets

Panel and pipe mounting brackets for the MD4 Series FRL assembly are available from ROSS Controls for installation on machine frames, panels, and pipe stands. Contact ROSS Controls for compatible bracket model numbers.

Replacement Filter Elements

Replacement filter elements in 5-micron and 40-micron grades are available to maintain rated filtration performance. Replace on a scheduled interval or when elevated differential pressure indicates element saturation.

Electronic Drain Power Supply Accessories

Power supply cables and connector accessories for the electronic drain option are available. Confirm compatibility with ROSS Controls at time of order.

Replacement Bowls and Seals

Replacement polycarbonate and aluminum bowls with associated seals are available as service parts for the MD4 Series.

Related Products & Accessories

• MD4 Series Filter/Regulator - Standalone MD4 Series filter/regulator for applications not requiring downstream lubrication. https://www.rosscontrols.com/en/series/73-md4-series
• MD3 Series FRL Combo - MD3 Series FRL combo for same port range up to 1/2" at 100 scfm with diaphragm regulator and expanded bowl options. https://www.rosscontrols.com/en/series/142-md3-series
• 143 Full-Size Series FRL Combo - Full-Size FRL combo for port sizes 1/4" to 3/4" at flow up to 140 scfm, with sight-feed or wick-feed lubricator. https://www.rosscontrols.com/en/series/143-full-size-series
• 141 Mid-Size Series FRL Combo - Mid-Size FRL combo for port sizes 1/4" to 1/2" at flow up to 100 scfm with piston regulator. https://www.rosscontrols.com/en/series/141-mid-size-series
• 145 Bantam Series Modular FRL - Bantam Series modular individual filter, regulator, and lubricator units for small-port modular assembly. https://www.rosscontrols.com/en/series/145-bantam-series

Frequently Asked Questions (FAQ)

Q: What makes the MD4 Series different from the 143 Full-Size Series?

A: The primary difference is flow capacity. The MD4 Series is rated for 205 scfm (5806 l/min) versus 140 scfm (3965 l/min) for the Full-Size Series, making it the higher-capacity option for the 3/8" to 3/4" port range. The MD4 Series also includes two gauge ports as standard, an extended aluminum bowl option for larger oil capacity, and an electronic drain option in addition to manual and float drain. Both use a diaphragm-type regulator.

Q: What port sizes are available?

A: The MD4 Series is available in 3/8", 1/2", and 3/4" port sizes.

Q: What is the maximum rated flow?

A: The MD4 Series handles up to 205 scfm (5806 l/min), the highest capacity in this FRL combo series group.

Q: What bowl options are available?

A: Polycarbonate with steel shatterguard (150 psig, 125 degrees F), aluminum with clear sight glass (200 psig, 175 degrees F), and extended aluminum with sight glass (200 psig, 175 degrees F with larger oil capacity). The aluminum bowl is required for temperatures above 125 degrees F or pressures above 150 psig.

Q: What are the drain options?

A: Manual drain requires operator-initiated drainage. Automatic (float) drain uses a float-actuated mechanism that automatically discharges condensate when it reaches a set level. Electronic drain uses an electrically actuated solenoid on a timer or demand signal for fully automated condensate removal. Electronic drain requires a 24 VDC or 110 VAC power supply.

Q: Why does the MD4 Series have two gauge ports?

A: Two gauge ports allow the pressure gauge to be positioned on the left or right side of the regulator body to suit installation space constraints and access requirements. The unused port is plugged.

Q: What is the temperature limit for the aluminum bowl?

A: The aluminum bowl with clear sight glass is rated for operating temperatures up to 175 degrees F (80 degrees C) and 200 psig, suitable for installations in elevated-temperature industrial environments.

Q: What is the benefit of the extended aluminum lubricator bowl?

A: The extended aluminum lubricator bowl provides a larger oil reservoir capacity, extending the interval between lubricator refills. This reduces maintenance frequency in high-production, continuous-operation environments where minimizing maintenance interruptions is important.

Q: When should I choose the electronic drain?

A: The electronic drain is the preferred option for unmanned or lights-out production environments, remote installations, or any application where manual drain servicing is impractical or where automated condensate management is required as part of a control system.

Q: What type of regulator does the MD4 Series use?

A: The diaphragm-type regulator provides low hysteresis and precise output pressure control, maintaining stable downstream pressure across the full 205 scfm flow range.

Q: How is the output pressure set?

A: Pull the regulator adjustment knob upward to release the lock. Rotate clockwise to increase pressure or counterclockwise to decrease. Observe the integral pressure gauge and push the knob down to lock when the target pressure is reached.

Q: What lubricant is compatible?

A: Use petroleum-based oil with ISO 32 viscosity or lighter. Synthetic ester-based and phosphate-ester lubricants are incompatible with the standard nitrile seals used throughout the assembly.

Q: Can modular sections be individually replaced?

A: Yes. The modular design of the MD4 Series allows filter, regulator, and lubricator sections to be replaced or serviced independently without removing the complete assembly from the compressed air line.

Q: Is 205 scfm sufficient for large multi-actuator systems?

A: The 205 scfm capacity at 3/4" port sizing covers a wide range of high-volume applications. For systems with aggregate demand exceeding this rating, multiple FRL stations or parallel configurations may be required. Contact ROSS Controls for application engineering support.

Q: Where can I find product documentation?

A: Catalogs, data sheets, and installation instructions for the MD4 Series are available at rosscontrols.com. Contact ROSS Controls at (800) 438-7677 for configuration support.

Installation & Maintenance Guidelines

• Install the assembly with bowls oriented downward for proper condensate accumulation and drainage.
• Align the flow direction indicator on the assembly body with the compressed air supply flow direction.
• Position the assembly to provide access to the filter bowl drain, lubricator fill, sight dome, pressure gauge, and regulator adjustment knob. For electronic drain installations, route wiring to the 24 VDC or 110 VAC power supply.
• Apply thread sealant to all pipe port connections and tighten to the manufacturer-specified torque.
• Confirm that inlet pressure does not exceed 150 psig for polycarbonate bowls or 200 psig for aluminum bowls.
• Verify that ambient and air temperature remain within the rated range for the selected bowl material.
• Fill the lubricator bowl with petroleum-based ISO 32 or lighter oil before first use.
• Pressurize slowly after installation and check all connections, bowl seals, and drain valve with leak detection solution.
• Set regulated output pressure: pull the knob up to unlock, adjust to the target gauge reading, push down to lock.
• Observe the sight dome after start-up to confirm oil is delivering at the intended rate. Adjust if necessary.
• Drain the filter bowl on a regular maintenance schedule. Verify automatic float drain or electronic drain function at each inspection.
• For electronic drain, confirm that the timer or demand signal is correctly configured for the expected condensate volume.
• Replace the filter element on a scheduled interval or when elevated differential pressure is observed.

Warranty & Global Support

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

Technical support is available through ROSS Controls USA at (800) 438-7677 or by visiting rosscontrols.com.

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

Contact ROSS Controls at (800) 438-7677 or visit rosscontrols.com for product configuration, replacement parts, and distributor referral.

Download Catalog: https://www.rosscontrols.com/en/documents