SL32 Grease Injector — Adjustable Single-Line Metering
SL32 lubrication injectors are adjustable positive-displacement grease meters for single-line centralized systems. Single injectors or manifold assemblies (1–12 outlets) mount on the main supply line; each outlet delivers a metered shot of grease when line pressure rises and resets when pressure falls.
Discharge range: approximately 0.016–0.131 ml per cycle depending on indicator cap setting. Working pressure: about 8.3–24.1 MPa (83–241 bar class). Grease: NLGI #000 through #2. Body: steel with zinc plating; seals: Viton. Inlet NPTF 1/4; outlet NPT 1/8.
Indicator Cap Adjustment
The indicator cap position sets piston travel and therefore output volume:
- Fully tightened on the measuring chamber → minimum discharge
- Retract cap two full turns → maximum ~0.003 cu in. (~0.049 ml) per stroke on single-outlet units; manifold total scales with outlet count
- Turning beyond two full turns does not increase output further
- After setting, tighten the locknut against the indicator cap face
- If adjusted to less than ½ turn from minimum, verify discharge at the point with a catch test
Manifold kits include two mounting clips and screws (1/4″–20 × 1/2″ hex head) per assembly. Use grease type and viscosity per machine OEM; confirm compatibility with synthetic greases before fill.
Compare oil injectors: DLX single lubrication injector. System hubs: injection lubrication system · positive injector systems · grease pump.
- Parameter
SL32 Summary Specifications
| Parameter | Value |
|---|---|
| Outlets (manifold) | 1–12 outlets per assembly |
| Working pressure | 8.3–24.1 MPa |
| Opening pressure | ~60–90 kgf/cm² (6–8.8 MPa class) |
| Maximum pressure | ~200–240 kgf/cm² (20–24 MPa class) |
| Discharge per cycle | 0.016–0.131 ml/cyc (adjustable) |
| Lubricant | NLGI #000 – #2 grease |
| Body material | Steel, zinc-plated |
| O-ring | Viton |
| Inlet thread | NPTF 1/4 |
| Outlet thread | NPT 1/8 |
Request dimension drawing via page Ebook download or sales inquiry.
How SL32 Injectors Work in Single-Line Grease Systems
SL32 units are pressure-actuated positive-displacement injectors. When the main line pressure from the pump exceeds the injector opening threshold (~60–90 kgf/cm²), an internal piston advances and pushes a metered grease volume to the outlet. When line pressure falls during the pause interval, a spring returns the piston and the measuring chamber refills from the supply line.
- Pump energizes — controller or timer runs the grease pump; main header pressure rises.
- Injector opens — each SL32 on the line strokes once per cycle at its adjusted volume.
- Pressure relieves — pump stops or a relief valve opens; injectors recharge.
- Cycle repeats — interval set on timer or machine interlock.
Unlike continuous restrictors, SL32 delivers a fixed shot per cycle—ideal for bearings that need periodic grease renewal rather than constant flow.
SL32 vs DLX and Progressive Metering
| Feature | SL32 (this page) | DLX oil injector | Progressive block |
|---|---|---|---|
| Media | Grease NLGI #000–2 | Oil ISO #100–6500 | Grease or oil |
| Discharge | 0.016–0.131 ml/cyc (adjustable) | 0.025–0.5 ml/cyc (fixed suffix) | Sequential per outlet |
| Pressure class | Up to ~24 MPa | ~1.75–3.5 MPa | 15–40 MPa typical |
| Best for | Single-line grease injectors on mains | Oil PDI near points | Many outlets, one supply line |
Manifold & System Sizing
When using a 1–12 outlet manifold, total grease demand per cycle equals the sum of all adjusted injector outputs plus line compression losses. Size the pump so it can:
- Reach opening pressure at the farthest injector on the longest main run
- Deliver total ml/cycle for all outlets within the lubricate interval
- Hold pressure long enough for every piston to complete one full stroke
Group low-volume points on one manifold; assign high-consumption bearings to dedicated injectors if a single cap adjustment cannot cover the range. After any cap change, run a catch test at each outlet—collect grease in a small cup for three cycles and weigh or measure volume.
Recommended Pump & Plumbing Pairings
- 20703 / CS cabinet pumps — machine-mounted automatic grease, 15–25 MPa class
- SK-505 DC pump — compact mobile circuits with few injectors
- High-pressure hand pump — commissioning and backup
- Main line: heavy-wall grease hose or steel lubrication pipe; secondary: short NPT 1/8 runs to fittings
- Filtration: grease filter upstream of injectors on large plants
Installation & Commissioning
- Mount manifold or single injector on the main supply with inlet NPTF 1/4—use thread sealant suitable for grease systems; torque per plant standard, not beyond injector body rating.
- Route each NPT 1/8 outlet to the lube point with minimal bends; support tubing to avoid vibration fatigue.
- Set indicator cap per OEM dose; tighten locknut against cap face.
- Prime main line—run pump until clean grease exits the highest point.
- Execute three full cycles; confirm grease at every outlet before returning equipment to service.
- Record cap turns and outlet assignment on the machine lubrication chart.
Troubleshooting
| Symptom | Likely cause | Action |
|---|---|---|
| No discharge at one outlet | Blocked NPT run, cap at minimum, wrong install direction | Clear line; adjust cap; verify flow path toward point |
| All outlets weak | Main pressure below opening (~60–90 kg); empty reservoir | Check pump, timer, and grease level; verify line leaks |
| Over-lubrication | Cap turned out too far; wrong grease grade (too soft) | Reset cap; retest catch volume; use NLGI per OEM |
| Leak at Viton seal | Incompatible fluid, over-pressure, aged O-ring | Replace O-ring; confirm NLGI #000–2 only; check max pressure |
| Manifold uneven output | Different cap settings; one stuck piston | Balance adjustments; disassemble and clean affected unit |
System architecture: injection lubrication system · positive injector systems · request SL32 manifold BOM.
Before you buy: read our grease fitting types guide.
Approximately 60–90 kgf/cm² (roughly 6–8.8 MPa)—injectors remain closed until main line pressure exceeds this threshold.
Up to about 200–240 kgf/cm² (20–24 MPa) depending on model and temperature. Do not exceed pump or fitting ratings downstream.
NLGI #000 through #2. Softer grades meter more easily in cold service; verify catch volume after changing grease brand.
0.016–0.131 ml per cycle via indicator cap position. Two full turns out from minimum typically gives maximum rated stroke.
Zinc-plated steel body for corrosion resistance in industrial environments; Viton O-rings for grease and synthetic compatibility.
Inlet NPTF 1/4; outlet NPT 1/8. Use thread sealant or tapered fittings per your plant standard—do not over-torque into injector body.
Download the PDF from the page Ebook block or request a GA drawing from IsoHiTech sales with your manifold outlet count.
It’s NPT1/8.
