Mid-Size Series Port Sizes 1/4" to 1/2"; Flow to 110 scfm (3115 l/min)

Product Overview

The ROSS Controls Mid-Size Series is a line of modular sight-feed lubricators for pneumatic systems operating on 1/4, 3/8, and 1/2 inch port sizes with flow requirements up to 110 scfm (3,115 l/min). The Mid-Size Series bridges the gap between compact Bantam and Miniature units and the larger Full-Size and MD3 series, providing the right capacity for medium-duty pneumatic circuits found throughout industrial manufacturing.

Sight-feed design is the defining technology of the Mid-Size Series. Unlike wick-feed lubricators, the sight-feed mechanism delivers oil through a transparent nylon dome positioned on top of the lubricator body, where drops of oil are visible as they enter the airstream. This direct visual indication allows maintenance personnel to confirm that oil is being delivered and to calibrate the delivery rate by observing drop frequency without instrumenting the system.

The external tamper-resistant adjustment allows authorized personnel to modify oil delivery rate without special tools, while providing a degree of protection against unintended changes. This combines the flexibility of field-adjustable oil delivery with assurance that settings are maintained during normal production operations.

The zinc body construction of the Mid-Size Series supports higher operating pressures and temperatures compared to acetal or aluminum bodies, with the zinc bowl variant extending the metal bowl rating to 200 psig (14 bar) and 175 F (80 C). Bowl options include polycarbonate with a zinc shatterguard for standard industrial conditions and zinc metal for more demanding pressure and temperature requirements.

Key Engineering Features

• Sight-Feed Design with Visible Oil Drop Indicator - Transparent nylon dome on top of the lubricator allows maintenance personnel to observe individual oil drops entering the airstream, providing direct visual confirmation of lubricant delivery and easy calibration of drop rate.
• External Tamper-Resistant Adjustment - Oil delivery rate is adjustable from outside the unit using the external adjusting knob. The tamper-resistant design requires deliberate action to change settings, preventing accidental misadjustment during production.
• Modular or Inline Mounting - Mounts directly in a modular FRL assembly with other Mid-Size Series components or as a standalone inline lubricator in existing 1/4 to 1/2 inch pipe circuits. Flexible installation reduces system design constraints.
• Polycarbonate or Zinc Bowl - 4-oz (120-ml) polycarbonate bowl with integral zinc shatterguard for standard applications to 150 psig (10 bar) and 125 F (52 C). Zinc metal bowl extends pressure to 200 psig (14 bar) and temperature to 175 F (80 C).
• Quick-Fill Cap Option - Optional quick-fill cap allows oil reservoir refilling under system pressure without removing the bowl, minimizing production interruption during routine maintenance.
• Zinc Body Construction - Zinc die-cast body provides superior pressure and temperature resistance compared to acetal or polymer bodies. Compatible with standard industrial compressed air service.
• 4-oz (120-ml) Bowl Capacity - Larger bowl volume compared to Bantam and Miniature Series reduces oil refill frequency for medium-duty applications. Provides longer intervals between maintenance checks.
• Nitrile Seals - Standard nitrile seals provide petroleum oil compatibility across the full rated temperature range of 40 to 175 F (4 to 80 C) for metal bowl configurations.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

General Industrial Pneumatic Systems

• Pneumatic cylinder circuits supplying medium-bore actuators (25 mm to 80 mm bore) on material handling equipment, indexing tables, and clamping fixtures that require reliable air line lubrication at 20 to 100 scfm flow rates.
• Multi-cylinder pneumatic circuits in assembly automation where a single Mid-Size lubricator in a 3/8 or 1/2 inch header services multiple branch circuits simultaneously through the modular FRL assembly.
• Maintenance tool supply headers in manufacturing facilities providing lubricated air to pneumatic impact wrenches, ratchets, and grinders at workstations throughout the plant.

Automotive Manufacturing

• Assembly line pneumatic torque tools, nut runners, and power screwdrivers in automotive body shop and final assembly operations, where 1/2 inch supply headers at 80 to 100 scfm require Mid-Size lubricators to maintain tool performance.
• Pneumatic cylinder banks in body transfer fixtures and welding jigs, where a modular FRL assembly at the fixture header provides clean, regulated, lubricated air to multiple cylinder circuits.
• Paint shop pneumatic actuators for door opening mechanisms, hood lift systems, and body transfer equipment in environments where 40 to 125 F temperature range is consistent with polycarbonate bowl selection.

Material Handling and Conveyance

• Pneumatic diverters, pushers, and stops on conveyor systems, where medium-bore cylinders cycling at production rates of 10 to 60 cycles per minute require consistent lubrication to maintain seal life across multi-shift operations.
• Pneumatic lift tables and scissor lifts in warehouses and distribution centers, where 3/8 inch air supply headers serve large-bore cylinders and require lubricator capacity above the Bantam or Miniature Series range.
• Pneumatic pallet conveyor transfer units and deck plates in automated warehouses, where modular installation allows filter-regulator-lubricator stations to be configured and replaced as a module during scheduled maintenance windows.

Plastics and Rubber Processing

• Injection molding machine pneumatic ejector circuits, mold clamp unlock actuators, and robot take-out pneumatic arms, where 3/8 and 1/2 inch supply ports at 50 to 110 scfm match the Mid-Size Series capacity range.
• Extrusion line pneumatic die-face cutting actuators and strand pelletizer clamping circuits, where zinc bowl construction supports the higher ambient temperatures and pressures common near extruder heads.
• Thermoforming machine pneumatic forming box actuators and part ejectors, where reliable lubrication prevents actuator seal degradation during continuous high-cycle production runs.

Metal Fabrication and Stamping

• Pneumatic die clamping and part ejection circuits on stamping presses, where 1/2 inch air supply lines at 80 to 110 scfm support multiple cylinder circuits in the press cell.
• Pneumatic toolchanger actuators on machining centers and transfer machines, where lubricated air supply maintains tool retention spring and cylinder seal integrity during continuous production.
• Pneumatic bar feeder and part chucking actuators on CNC lathes and turning centers, where inline or modular Mid-Size lubricators in the machine air circuit provide continuous lubrication during spindle operation.

Food Processing (Non-Contact Zones)

• Pneumatic actuators on packaging lines in secondary and tertiary packaging zones, where polycarbonate bowl transparency allows quick visual oil level checks during sanitation walkthroughs.
• Pneumatic can or bottle handling systems in beverage processing facilities, where 3/8 inch air supply circuits require Medium-duty lubrication for cylinder-driven pushers, rotary escapements, and pneumatic conveyors.
• Pneumatic bag sealing and carton forming equipment, where the external tamper-resistant adjustment allows qualified maintenance technicians to optimize oil delivery without opening control enclosures or using special tooling.

Ordering and Model Number Configuration

Mid-Size Series lubricators are ordered by specifying port size, thread type, bowl material, and fill method. The zinc body is standard across all models.

NPT models have no prefix. G (BSPP) thread models are prefixed with C.

Polycarbonate bowl models (5111B) are rated to 150 psig (10 bar) and 125 F (52 C). Zinc bowl models (5112B) are rated to 200 psig (14 bar) and 175 F (80 C).

For modular FRL assembly, order the appropriate Mid-Size Series filter and regulator to match port size and mounting configuration.

Accessories

Mid-Size Series Filters

ROSS Mid-Size Series filters with 5-micron polyethylene elements, polycarbonate or zinc bowl, internal automatic or manual drain. Available in modular or inline mounting to match Mid-Size lubricator configurations.

Mid-Size Series Regulators

Mid-Size Series piston-type or diaphragm-type regulators for 1/4 to 1/2 inch ports. Adjustable outlet pressure to 200 psig (14 bar). Self-relieving and non-relieving options. Integral gauge port.

Related Products & Accessories

• 104 Bantam Series Lubricators - Compact modular wick-feed lubricators for 1/8 and 1/4 inch ports with tube fitting options. Flow to 27 scfm. https://www.rosscontrols.com/en/series/104-bantam-series
• 105 Miniature Series Lubricators - Inline wick-feed lubricators with internal tamper-proof adjustment for 1/8 and 1/4 inch ports. High-flow and low-flow models. Flow to 25 scfm. https://www.rosscontrols.com/en/series/105-miniature-series
• MD3 Series Lubricators - Modular sight-feed lubricators with transparent dome and removable external adjustment for 1/4 to 1/2 inch ports. Flow to 150 scfm. https://www.rosscontrols.com/en/series/107-md3-series
• 108 Full-Size Series Lubricators - Modular or inline sight-feed and wick-feed lubricators for 1/4 to 3/4 inch ports. 8-oz bowl capacity. Flow to 140 scfm. https://www.rosscontrols.com/en/series/108-full-size-series
• MD4 Series Lubricators - Modular sight-feed lubricators with transparent dome for 3/8 to 3/4 inch ports. Extended bowl option. Flow to 205 scfm. https://www.rosscontrols.com/en/series/109-md4-series

Frequently Asked Questions (FAQ)

Q: What is a sight-feed lubricator and how does it differ from a wick-feed design?

A: A sight-feed lubricator uses a pressure differential across the inlet and outlet to draw oil up through a needle valve and into a transparent sight dome. Drops of oil fall through the dome and are carried into the airstream. The operator can see each individual drop, making delivery rate visible and easy to calibrate. A wick-feed lubricator draws oil by capillary action through a wick, providing continuous delivery without visible drop counting but offering no visual confirmation of oil flow.

Q: What does tamper-resistant adjustment mean on the Mid-Size Series?

A: Tamper-resistant adjustment means the external adjusting knob is accessible for authorized maintenance personnel but is designed to require a deliberate intentional action to change settings. This prevents incidental bumping or accidental rotation from altering oil delivery rates during production. It is not a locked or sealed adjustment, so qualified personnel can adjust settings when required without special tools.

Q: What is the minimum flow required for the Mid-Size lubricator to deliver oil?

A: The minimum flow is 2 scfm (0.94 l/s) at 100 psig (6.9 bar) inlet pressure. Below this threshold, the pressure differential required for the sight-feed mechanism to draw oil is insufficient. For applications with lower flow rates, select the 105 Miniature Series low-flow models.

Q: Can the Mid-Size Series be used as an inline lubricator without a filter or regulator?

A: Yes. The Mid-Size Series supports both modular and inline mounting configurations. In inline mode, the lubricator installs directly in the pipe circuit without companion filter or regulator units. However, it is strongly recommended to supply filtered air upstream to prevent particulate contamination of the oil reservoir and sight dome.

Q: What is the difference between the polycarbonate and zinc bowl options?

A: The polycarbonate bowl with zinc shatterguard is rated to 150 psig (10 bar) and 125 F (52 C). The transparent bowl allows visual inspection of oil level without removing the bowl. The zinc metal bowl is rated to 200 psig (14 bar) and 175 F (80 C) and is required for higher-pressure or higher-temperature applications. Zinc bowls must be used where chemical exposure to solvents or cleaning agents may degrade polycarbonate.

Q: How is the oil delivery rate set on a sight-feed lubricator?

A: Turn the external adjusting knob clockwise to decrease oil delivery and counterclockwise to increase delivery. Observe the oil drops falling through the transparent sight dome. A typical starting point for pneumatic tool circuits is 1 to 2 drops per minute per 20 scfm of flow. Adjust until the desired drop rate is observed at the actual operating flow conditions.

Q: Is the sight dome replaceable if it becomes cloudy or cracked?

A: Yes. The sight dome is a nylon component within the replaceable cartridge assembly. All working parts of Mid-Size Series lubricators are contained in a single cartridge that can be removed and replaced in the field. Contact ROSS Controls or an authorized distributor for the correct cartridge part number for your model.

Q: What is the bowl removal clearance required for servicing?

A: Bowl removal requires approximately 3.1 inches (79 mm) of clearance below the bottom of the lubricator body to swing the bowl clear of the unit. Verify this clearance is available in the installation location before mounting the lubricator in a panel or enclosure.

Q: Can the Mid-Size Series be used in compressed air systems above 150 psig?

A: Yes, by selecting the zinc bowl model (5112B series), which is rated to 200 psig (14 bar). The polycarbonate bowl models are limited to 150 psig. Verify that the inlet pressure from the upstream regulator does not exceed the rating for the bowl material specified.

Q: Are NPT and BSPP threads available in all port sizes?

A: Yes. Both NPTF (NPT) and G (BSPP) thread options are available for all three port sizes: 1/4, 3/8, and 1/2 inch. Standard models use NPTF threads. G thread models are prefixed with C in the model number (e.g., C5111B3007 for 3/8 G, polycarbonate, fill port).

Q: What lubricant should be used in the Mid-Size Series?

A: Use petroleum-based lubricant with ISO 32 viscosity or lighter and an aniline point between 180 F and 220 F. Standard pneumatic tool oil meeting these specifications is appropriate. Do not use synthetic lubricants, phosphate-ester fluids, or additives incompatible with nitrile seals.

Q: How does the quick-fill cap option benefit maintenance operations?

A: The quick-fill cap installs on the oil fill port and incorporates a spring-loaded check valve. Maintenance personnel insert an oil dispenser nozzle into the check valve, and oil flows into the reservoir against system pressure. When the nozzle is removed, the check valve seals, maintaining system pressure. This eliminates the need to shut down the air system or remove the bowl to add oil, reducing maintenance time to under one minute per lubricator.

Installation & Maintenance Guidelines

• Install the lubricator downstream of the filter and regulator in the air treatment sequence. Lubricating unfiltered air introduces contaminants into the oil reservoir and downstream pneumatic components.
• Mount with the bowl in the downward position for correct sight dome oil level and sight-feed operation.
• For modular FRL assembly, follow ROSS module assembly instructions to ensure proper O-ring seating and tie bolt torque.
• Verify inlet pressure does not exceed 150 psig for polycarbonate bowl or 200 psig for zinc bowl at any operating condition.
• After installation, start the air system and observe the sight dome. Set the adjusting knob to achieve the desired oil drop rate at the actual operating flow condition.
• Use only petroleum-based lubricant with ISO 32 viscosity or lighter. Do not introduce incompatible fluids into the oil reservoir.
• Ensure bowl removal clearance of at least 3.1 inches (79 mm) is available below the lubricator body for bowl removal during servicing.
• Do not over-tighten the bowl. Hand-tighten and then turn one additional quarter turn. Excessive torque can crack polycarbonate bowls.
• Inspect the sight dome for cloudiness, cracks, or oil deposits periodically. A cloudy dome impairs visibility of oil drops and indicates contamination or material degradation.

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 is available through ROSS 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 (248) 764-1800, or visit rosscontrols.com for product configuration, technical support, and distributor locator services.

Download Catalog: https://www.rosscontrols.com/en/documents/198/ROSS_FRL_Combination_Units_Filter_Regulator_Lubricator.pdf