Nominal bore Lubricators

Technical Specifications – Nominal Bore Lubricators

Applications – Matching Lubricator to Valve Bore

Field Example – Offshore Platform with Mixed Valve Sizes

A fixed platform in the South China Sea has:

• 2″ valves on mud return lines (12 valves)

• 3″ valves on choke manifold (8 valves)

• 4″ valves on kill manifold (4 valves)

Before switching to SJ nominal bore lubricators, technicians used a single 5cc lubricator for all valves. 2″ valves received 5 strokes (25cc) – over‑greased, seals damaged. 4″ valves received 20 strokes (100cc) – technician stopped at 15 strokes because arm got tired.

After implementing color‑coded NB lubricators:

• Blue (2cc) for 2″ valves: 8 strokes → 16cc perfect

• Green (5cc) for 3″ valves: 10 strokes → 50cc perfect

• Yellow (10cc) for 4″ valves: 9 strokes → 90cc perfect

Valve seizure rate dropped 80%. Technician fatigue complaints stopped.

Product Types – Nominal Bore Series

Type 1: SJ‑LUB‑NB‑2 (2″ Bore)

Ultra‑fine control for small valves.

• Best for: 2″ plug valves on mud manifolds, cementing heads, small well test lines

• Key feature: 2cc per stroke – impossible to over‑grease a 2″ valve

• Optional: Extended reservoir (300cc) for high‑frequency lubrication schedules

Type 2: SJ‑LUB‑NB‑3 (3″ Bore)

The workhorse. Most common offshore valve size.

• Best for: 3″ choke & kill valves, standpipe valves, fracturing distribution valves

• Key feature: 5cc stroke – industry standard volume, compatible with most greases

• Optional: Pneumatic version for high‑volume fracturing spreads (air‑driven, same 5cc displacement)

Type 3: SJ‑LUB‑NB‑4 (4″ Bore)

High volume for large valves.

• Best for: 4″ zipper frac manifolds, high pressure mud pumps, large choke manifolds

• Key feature: 10cc stroke – 8–12 strokes per valve, same handle pulls as a 2″ valve

• Optional: Wheels and towing handle – NB‑4 weighs 5.8 kg empty, 8 kg full

Type 4: SJ‑LUB‑NB‑5 (5″ Bore)

Heavy duty for the largest plug valves.

• Best for: 5″ mud manifolds on ultra‑deep rigs, large bore well control systems

• Key feature: 15cc stroke, 1,500cc reservoir – lubricate 10 valves before refilling

• Included: Right‑angle coupler standard – straight coupler won’t clear 5″ valve body

Type 5: Bore‑Specific Check Valve Fittings – SJ‑CV‑NB

Permanent lubricator fittings designed for specific valve bore sizes. Thread size and reach optimized.

• NB‑2 fitting: 1/8″ NPT, short stem

• NB‑3 fitting: 1/8″ NPT, standard stem

• NB‑4 fitting: 1/4″ NPT, extended stem

• NB‑5 fitting: 1/4″ NPT, extended stem with swivel

OEM Customized Solutions – Lubricators for Non‑Standard Valve Bores

Not all valves follow standard bore sizes. 2‑1/16″, 2‑9/16″, 3‑1/8″, 4‑1/16″ are common API sizes. SJ can build lubricators for any valve bore.

What we customize:

Custom lubricator design process:

Step 1 – Valve measurement: You provide valve make, model, bore size, and photos of injection port location.

Step 2 – Displacement calculation: We calculate grease cavity volume from valve drawings. Set lubricator displacement to achieve 8–12 strokes per full lubrication.

Step 3 – Coupler design: Match thread size, reach length, and angle to your valve body.

Step 4 – Prototype (optional): Sample unit for your testing.

Step 5 – Production: 4–6 weeks for custom bore lubricators.

Why Choose SJ for Nominal Bore Lubricators?

Frequently Asked Questions (FAQ)

Q1: What is "nominal bore” and why does it matter for a lubricator?

A: Nominal bore is the internal diameter of the valve (e.g., 2″, 3″, 4″). Larger bore valves have larger grease cavities – they need more grease per lubrication. A lubricator designed for a 2″ valve delivers 2cc per stroke; a 4″ valve needs 10cc per stroke. Using the wrong bore lubricator leads to over‑greasing (small valve) or under‑greasing (large valve).

Q2: Can I use a NB‑4 lubricator on a 3″ valve?

A: Physically yes, but you'll inject 10cc per stroke into a cavity designed for 50cc total. That’s 5 strokes = full cavity. But the handle effort is higher (10cc piston requires more force). Better to use NB‑3 (5cc) for 3″ valves. SJ sells bore‑specific for a reason.

Q3: How do I know which bore size lubricator to order?

A: Check the valve nameplate. It will state the nominal bore (e.g., "2″ API 6A”, "3″”, "4″”). If the nameplate is missing, measure the flange outer diameter or ask SJ – we have a cross‑reference chart by valve make and model.

Q4: Can I get a NB‑4 lubricator with 105 MPa pressure rating?

A: Yes – all NB lubricators are available in 70, 105, or 140 MPa pressure ratings. Specify both bore size and pressure rating when ordering. Example: "SJ‑LUB‑NB‑4‑105” (4″ bore, 105 MPa).

Q5: What is the typical stroke count for a 4″ valve with NB‑4?

A: A 4″ plug valve requires 80–120cc of grease. NB‑4 delivers 10cc per stroke. Recommended: 8–12 strokes. Compare to a standard 5cc lubricator: 16–24 strokes. NB‑4 cuts handle pulls in half.

Q6: Do you make pneumatic NB lubricators?

A: Yes – NB‑3 and NB‑4 are available in pneumatic versions for high‑volume fracturing spreads. Air‑driven, same displacement per cycle (5cc or 10cc), continuous operation.

Q7: How do I clean a NB lubricator between grease types?

A: Disassemble (threaded cylinder). Clean with mineral spirits or diesel. Replace seals if switching to incompatible grease (e.g., from lithium to PTFE). SJ offers seal kits for each NB model.

Q8: What is the warranty on NB lubricators?

A: 12 months. Pressure gauge: 6 months. Coupler and seals: 90 days (wear items). Extended warranty not offered.

Q9: Can I get a NB lubricator with a digital stroke counter?

A: Yes – special order. Digital counter mounts on handle pivot, counts each stroke. Helps maintain lubrication records for critical valves.

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