A constant-feed line oiler (also called a constant feed lubricator or gravity feed oiler) is a precision lubrication device designed to deliver a continuous, controlled flow of oil to machinery parts, bearings, or air lines.Unlike intermittent or pressure-feed systems, a constant-feed oiler relies on gravity or capillary action and adjustable needle valves to maintain a steady rate of oil flow typically drop-by-drop into the lubrication point or air line. Its purpose is to ensure critical moving components receive a continuous film of lubricant to reduce friction, wear, and overheating.
Design:
- Reservoir (Oil Cup): Holds a supply of lubricating oil; can be transparent (for visibility) or metal.
- Needle Valve or Flow Adjuster: Regulates oil flow rate by adjusting the orifice size.
- Sight Feed Glass: Transparent section showing oil drops as they pass, allowing visual monitoring of feed rate (drops per minute).
- Outlet Nozzle/Line Fitting: Connects to lubrication line, bearing housing, or pneumatic system.
- Body/Base: Supports reservoir and houses metering and sealing components.
- Vent Cap or Breather: Prevents vacuum lock and allows smooth oil flow.
- Mounting Bracket/Threads: For attaching directly to equipment or lubrication manifolds.
Applications: Constant-feed line oilers are widely used where continuous, low-volume lubrication is required for efficient, reliable operation.
- Machining/Manufacturing: Spindle and bearing lubrication on lathes, grinders, mills
- Textile Machinery: Yarn guides, roller bearings, and spindles
- Food Processing: Low-pressure conveyors and chain drives (with food-grade oil)
- Paper Mills: Felt rolls, bearings, and line shafts
- Foundries & Steel Plants: Lubricating roll bearings and valve linkages
- Pneumatic Systems: Inline installation to maintain oil mist for air tools and actuators
- Engines and Compressors: Feeding oil to crankcase vents, cylinder walls, or line bearings
- Marine/Offshore: Rust prevention in air-driven systems and marine engines
Materials:
- Body/Base: Brass, Aluminum, or Zinc alloy – Corrosion resistance, machinability
- Reservoir/Cup: Glass, Polycarbonate, or Aluminum – Oil visibility and containment
- Sight Glass: Borosilicate glass or Acrylic – High clarity and oil resistance
- Valve Components: Brass or Stainless Steel – Precision metering and corrosion resistance
- Needle/Seat: Hardened Stainless Steel – Wear and chemical resistance
- Seals/Gaskets: Nitrile (Buna-N) or Viton – Oil and temperature resistance
- Mounting Hardware: Plated Steel or Brass – Structural support and corrosion resistance
