MD3 & MD4 MD3 & MD4

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Product Overview

The ROSS Controls provides male and female end port blocks for ROSS MD3 and MD4 Series modular FRL assemblies. These end ports attach to the inlet and outlet ends of MD3 or MD4 FRL modules using the MD Series module connecting clamp system, enabling either male or female threaded connections to supply and downstream piping at the ends of the FRL assembly.

The Series offers both female end port (R-118-100 series) and male end port (R-118-109 series) configurations in 1/4, 3/8, 1/2, and 3/4 inch pipe sizes with both NPTF and G (BSPP) thread options. This 22-variant model family provides complete coverage of all MD3 and MD4 installation piping configurations.

A key design feature of the MD Series end port system is the clamp attachment method. The end port is attached to the MD3 or MD4 module using the module connecting clamp (R-A118-105), enabling rapid removal and reinstallation of the entire FRL assembly without unthreading the pipe fitting from the end port. This significantly reduces maintenance downtime when an MD3 or MD4 FRL assembly requires service or replacement.

The ability to specify either male or female end ports at each assembly end provides maximum piping flexibility. Male end ports connect to female-threaded fittings in the supply line; female end ports connect to male-threaded pipe nipples or fittings. Either configuration allows all modules of the FRL assembly to be removed together as a unit for service, with only clamp release required to free the assembly from the piping.

Key Engineering Features

Clamp-Attached for Fast Assembly Removal - MD Series end ports attach via the module connecting clamp system (R-A118-105), allowing the complete FRL assembly to be removed for service without unthreading or disturbing the supply and downstream piping connections.
Male and Female Configurations - R-118-100 series (female) and R-118-109 series (male) end ports provide two piping interface options to match the existing pipe fittings at the installation without requiring intermediate adapters.
1/4 to 3/4 Inch Port Sizes - Available in 1/4, 3/8, 1/2, and 3/4 inch pipe sizes to match the full range of MD3 (1/4, 3/8, 1/2 inch) and MD4 (3/8, 1/2, 3/4 inch) Series FRL supply and downstream piping.
NPTF and G Thread Options - Both NPTF (standard models) and G (BSPP) thread configurations (W suffix models) provide global installation compatibility for MD3 and MD4 FRL systems in both North American and international facilities.
Compatible with MD3 and MD4 Series FRL Modules - The R-118-100 and R-118-109 end port families are specifically engineered for the MD3 and MD4 Series modular interface, distinct from the standard Mid-Size and Full-Size Series port blocks of the 172 Series.
Auxiliary Port Capability - An extra port block can be placed between MD Series modules to provide two auxiliary 1/4 NPTF ports for additional instrumentation, gauge, or drain connections without modifying the main FRL assembly ends.

Technical Specifications

General Specifications

Parameter	Specification
Series	173 - MD3 and MD4 End Port Blocks
Female End Port Models (NPTF)	R-118-100-2 (1/4"), R-118-100-3 (3/8"), R-118-100-4 (1/2"), R-118-100-6 (3/4")
Female End Port Models (G/BSPP)	R-118-100-2W (1/4"), R-118-100-3W (3/8"), R-118-100-4W (1/2"), R-118-100-6W (3/4")
Male End Port Models (NPTF)	R-118-109-2F (1/4"), R-118-109-3F (3/8"), R-118-109-4F (1/2"), R-118-109-6F (3/4")
Male End Port Models (G/BSPP)	R-118-109-2FW (1/4"), R-118-109-3FW (3/8"), R-118-109-4FW (1/2"), R-118-109-6FW (3/4")
Port Sizes	1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch
Port Types	Female (R-118-100 series) and Male (R-118-109 series)
Thread Types	NPTF (standard) and G/BSPP (W suffix)
Attachment Method	Module connecting clamp (R-A118-105)
Compatible Units	MD3 Series (1/4, 3/8, 1/2 inch ports, up to 110 scfm) and MD4 Series (3/8, 1/2, 3/4 inch ports, up to 230 scfm)
Price - R-118-100-2 (1/4" Female NPTF)	$16.25
Price - R-118-100-2W (1/4" Female G)	$16.25
Price - R-118-100-3 (3/8" Female NPTF)	$16.25

Temperature Ratings

The Series end ports operate within the temperature range of the MD3 and MD4 Series FRL assemblies they serve.

Configuration	Ambient Temperature	Media Temperature
MD3 Series Polycarbonate Bowl Assembly	40 to 125F (4 to 52C)	40 to 125F (4 to 52C)
MD3 / MD4 Metal Bowl Assembly	40 to 125F (4 to 52C)	40 to 175F (4 to 80C)
MD4 Series Polycarbonate Bowl Assembly	40 to 125F (4 to 52C)	40 to 125F (4 to 52C)

Important: Temperature limits are determined by the assembled MD3/MD4 FRL unit components. The end port hardware is compatible with the full operating temperature range of MD Series FRL assemblies.

Certifications & Compliance

Certification/Standard	Detail
Thread Standard	NPTF thread per ANSI/ASME B1.20.3 (North American); G/BSPP thread per ISO 228 (International).
Platform Compatibility	Specifically designed for the ROSS MD3 and MD4 Series modular FRL interface geometry and module connecting clamp attachment system (R-A118-105).

Typical Applications & Industries

High-Flow Pneumatic Supply Systems

MD4 Series three-unit FRL assembly (filter, regulator, lubricator) with R-118-100-6 female end ports at inlet and outlet for a 3/4 inch NPT supply circuit providing up to 230 scfm to a large pneumatic distribution system.
MD3 Series modular FRL with R-118-100-4 female end ports at 1/2 inch NPT supply for a high-flow press line air preparation station, where the clamp attachment enables rapid FRL service by disconnecting at the clamps without disturbing 1/2 inch supply fittings.
MD4 Series FRL assemblies with mixed-size end ports: R-118-100-6 female at inlet (3/4 inch supply header) and R-118-100-4 female at outlet (1/2 inch downstream distribution), providing supply line size reduction at the air preparation point.

Automotive and Metal Fabrication

MD3 Series FRL assemblies with R-118-109-3F male end ports at welding cell supply risers for direct connection to female-threaded supply valves without intermediate pipe nipples.
MD4 Series high-flow FRL installations at stamping press supply risers where R-118-100-4 female end ports connect to 1/2 inch NPT supply elbows, and the clamp attachment allows monthly FRL element replacement without shutting down the entire press line supply.
International automotive plants using D-prefix G thread end ports (R-118-100-2W through R-118-100-6W) for integration with metric pipe fittings on European-built equipment.

Process and Chemical Industries

MD3 Series FRL assemblies with R-118-100-2 female end ports at instrument air supply distribution points providing clean, regulated 1/4 inch supply connections to pneumatic instruments and control valves.
MD4 Series large-capacity filter assemblies with R-118-100-6 female end ports at 3/4 inch compressed air supply headers in process facilities, where high condensate loads require frequent filter element replacement facilitated by the clamp-release assembly removal system.
Extra port blocks installed between MD Series modules to provide auxiliary 1/4 NPTF ports for differential pressure gauge (174 Series) connections without modifying assembly end connections.

Food and Beverage Processing

MD3 Series FRL with R-118-100-4W G thread female end ports for integration with metric stainless piping in European food processing plants requiring high-flow (110 scfm) clean air supply.
MD4 Series modular FRL assemblies in beverage filling line supply panels using R-118-100-6 female end ports for 3/4 inch NPT connections to main supply headers feeding multiple filling nozzle actuator circuits.
MD3 or MD4 assemblies where clamp-attached end ports reduce maintenance downtime during scheduled filter element replacement in continuous-operation food and beverage production environments.

Ordering and Model Number Configuration

The Series MD3 and MD4 end port blocks are selected based on four parameters: female or male port type, pipe size, and thread type. Two end ports per FRL assembly are required - one inlet and one outlet, which may be different models if port types or pipe sizes differ.

Model Number Structure for Female End Ports: R-118-100-[SIZE][W]

Model Number Structure for Male End Ports: R-118-109-[SIZE]F[W]

R-118-100 = Female end port for MD Series FRL

R-118-109 = Male end port for MD Series FRL

2 = 1/4 inch pipe size

3 = 3/8 inch pipe size

4 = 1/2 inch pipe size

6 = 3/4 inch pipe size

F = Male port indicator (R-118-109 series)

W = G (BSPP) thread suffix (omit for NPTF)

Examples:

R-118-100-3 = 3/8 inch Female NPTF End Port

R-118-100-4W = 1/2 inch Female G (BSPP) End Port

R-118-109-2F = 1/4 inch Male NPTF End Port

Order two end ports per MD3 or MD4 FRL assembly: one for inlet, one for outlet.

Select female end port (R-118-100) when connecting to male pipe nipples or male fittings in the supply line.

Select male end port (R-118-109) when connecting to female fittings or female-threaded supply valves.

Add W suffix for G/BSPP thread; standard (no W) is NPTF.

The module connecting clamp (R-A118-105) is required for attaching end ports to MD Series modules; confirm clamp availability when ordering.

If an auxiliary port is needed between modules, order an extra port block - consult ROSS Controls for the extra port block model number.

Mixing female and male end ports at inlet and outlet is acceptable and common in practice.

Accessories

Series Female End Port Model Selection

R-118-100 series female end ports by pipe size and thread type.

Port Size	NPTF Model	G (BSPP) Model	Price
1/4 inch	R-118-100-2	R-118-100-2W	$16.25
3/8 inch	R-118-100-3	R-118-100-3W	$16.25
1/2 inch	R-118-100-4	R-118-100-4W	Consult ROSS
3/4 inch	R-118-100-6	R-118-100-6W	Consult ROSS

Series Male End Port Model Selection

R-118-109 series male end ports by pipe size and thread type.

Port Size	NPTF Model	G (BSPP) Model
1/4 inch	R-118-109-2F	R-118-109-2FW
3/8 inch	R-118-109-3F	R-118-109-3FW
1/2 inch	R-118-109-4F	R-118-109-4FW
3/4 inch	R-118-109-6F	R-118-109-6FW

MD Series Module Mounting Accessories

Required hardware for MD3 and MD4 FRL module assembly and mounting.

Description	Model Number
Bracket and Screw for MD Series	R-A118-103
Module Connecting Clamp	R-A118-105
Bracket, Screw, and Clamp Kit	R-A118-105M

Frequently Asked Questions (FAQ)

Q: What is the key difference between Series and 172 Series port blocks?

A: The Series (R-118-100 and R-118-109 models) are specifically designed for the MD3 and MD4 Series FRL modular interface and attach using the module connecting clamp system. The 172 Series (893K77 to 896K77) are for the standard Mid-Size and Full-Size Series FRL interface. The two series use different module connection geometries and are not interchangeable.

Q: What is the advantage of the clamp attachment method?

A: The clamp attachment allows the entire MD3 or MD4 FRL assembly (all modules) to be removed from the installation for service by simply releasing the clamps at the end ports, without unthreading the pipe fittings. This means the supply and downstream piping remain undisturbed, significantly reducing maintenance time and risk of piping damage.

Q: When should I use a male end port (R-118-109) versus a female end port (R-118-100)?

A: Use a female end port (R-118-100) when the supply line connection at the installation is a male pipe nipple or male fitting - the female port block threads over the male fitting. Use a male end port (R-118-109) when the supply line connection is a female-threaded fitting, valve, or manifold - the male end port threads into the female connection.

Q: Can I use different port types or sizes at inlet and outlet?

A: Yes. Mixing different port types (female inlet, male outlet) and different pipe sizes at inlet and outlet is fully supported. Select the model that matches each end's piping configuration independently.

Q: Is the module connecting clamp (R-A118-105) sold separately or included with the end port?

A: The module connecting clamp (R-A118-105) is sold separately. Each end port attachment requires one module connecting clamp. Verify that clamps are available when ordering end ports for new installations.

Q: How many Series end ports are required per MD3 or MD4 FRL assembly?

A: Two end ports are required per assembly - one at the inlet end and one at the outlet end. Additional end ports are not required for intermediate module connections; the R-A118-103/105 bracket and clamp system handles inter-module connections.

Q: Can extra port blocks be installed between MD Series modules?

A: Yes. An extra port block can be placed between any two MD Series modules to provide two auxiliary 1/4 NPTF ports. These auxiliary ports can connect pressure gauges, drain valves, or other accessories. If only one auxiliary port is used, the other must be capped with a pipe plug.

Q: Is G thread (BSPP) end port selection available for all four pipe sizes?

A: Yes. G thread variants are available for all four pipe sizes in both female and male end port types: sizes 2 (1/4"), 3 (3/8"), 4 (1/2"), and 6 (3/4") with the W suffix for G thread. This provides full global coverage for all MD Series FRL installation piping configurations.

Q: Do the series end ports require any sealing materials?

A: For NPTF connections: apply PTFE tape or pipe thread compound to male threads entering the female end port, or to the male end port threads. For G thread connections: use an O-ring face seal at the connection.

Q: Are Series models compatible with L-O-X lockout valve MD Series combinations?

A: Yes. MD3 and MD4 Series units can be modularly connected to L-O-X lockout valves. The Series end ports are used at the ends of such assemblies regardless of whether an L-O-X is included in the assembly.

Q: What tools are needed to assemble end ports with the module connecting clamp?

A: The module connecting clamp (R-A118-105) tightens with a 5/32 or 4 mm hex key (Allen wrench). These standard tools are all that is needed for MD Series module connection and end port attachment.

Q: Where can I get technical drawings for the series?

A: Dimensional drawings are in the ROSS FRL catalog (Form A10120) at rosscontrols.com. Contact ROSS Controls at (800) 438-7677 for direct technical support on MD3 and MD4 assembly configuration.

Installation & Maintenance Guidelines

Select the correct end port pipe size and type (female or male, NPTF or G) for each end of the MD3 or MD4 FRL assembly.
Assemble MD Series modules using the R-A118-103 bracket and R-A118-105 module connecting clamp at each inter-module junction.
Attach end port blocks to the inlet and outlet ends of the assembled FRL using module connecting clamps (R-A118-105).
Tighten module connecting clamps using a 5/32 or 4 mm hex key. Do not overtighten.
Connect supply piping to the inlet end port and downstream piping to the outlet end port using appropriate thread sealant for the thread type.
If extra port blocks are installed between modules for auxiliary connections, cap unused auxiliary ports with pipe plugs.
Mount the assembled FRL to the installation surface using R-A118-103 bracket and R-A118-105 clamp mounting hardware.
Pressurize the system and verify all end port connections, module interfaces, and auxiliary port connections for leaks.
To remove the FRL assembly for service: release the module connecting clamps at both end ports. The entire FRL assembly can then be lifted free from the end ports without disturbing supply and downstream piping.

Warranty & Global Support

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

Global technical support available through ROSS offices in the USA, 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, technical support, and distributor locator services.

For the complete MD Series FRL accessories catalog, dimensional drawings, and installation instructions, visit rosscontrols.com or contact ROSS Controls at (800) 438-7677.

Download Catalog: https://www.rosscontrols.com/en/series/173-md3-md4