Product Name: HP Cylinder / High Pressure Cylinder (Part No. 510000389)

Description:
This component is a high pressure cylinder, also known as an intensifier cylinder or pressure vessel, specifically designed for waterjet cutting systems . It is a precision-machined cylindrical pressure vessel that serves as the primary chamber where water is compressed to ultra-high cutting pressures (typically 60,000–90,000 PSI / 4,137–6,200 bar) . The cylinder houses the reciprocating ceramic plunger and high pressure seal assemblies , converting hydraulic energy into a high-pressure water stream for precision cutting.

The HP cylinder is subjected to extreme cyclical pressure loads, often reaching 300–600 MPa or higher, with a typical operational lifespan of approximately 3,000 hours before replacement is recommended . It is typically manufactured from high-strength alloy steel or precipitation-hardened stainless steel, designed to resist fatigue failure and maintain dimensional stability under millions of pressure cycles .

This specific part number (510000389) is identified as a DARDI G6D series high pressure cylinder, also cross-referenced as EP0420 .

Applications:

• Used as the primary high-pressure containment vessel within waterjet intensifier pumps

• Positioned between the hydraulic cylinder (low pressure side) and the check valve assembly

• Houses the reciprocating plunger and high pressure dynamic seals that compress water for cutting

• Suitable for ultra-high pressure waterjet systems operating at 60,000–90,000 PSI (approximately 4,137–6,200 bar)

• Compatible with DARDI G6D intensifier assemblies and other standard waterjet systems 

Features:

• High-Strength Construction: Manufactured from high-strength stainless steel or alloy steel with specialized heat treatment to withstand extreme pressure cycling 

• Precision-Machined Internal Bore: Features a precision-honed bore with exceptional surface finish to ensure proper plunger alignment and seal performance 

• High Fatigue Resistance: Engineered to withstand continuous pressure cycling from zero to maximum operating pressure without fatigue failure; typical service life of 3,000 hours 

• Threaded Connections: Features precision-machined threads for secure attachment to cylinder heads and check valve assemblies 

• Corrosion-Resistant: Material treatment resists erosion from water and water treatment additives

• Bore Integrity: Internal surface quality directly affects seal performance and cylinder service life 

Maintenance:

Failure Diagnosis:

• Water Leakage from Cylinder End: Visible water weeping from the cylinder connection indicates worn seals or cylinder bore damage

• Pressure Drop: Inability to maintain rated cutting pressure may indicate internal bore wear or cracking 

• Hot Cylinder Surface: A cylinder running noticeably hotter than normal indicates internal seal failure or component wear

• Loss of Cutting Performance: Reduced cutting efficiency or erratic pressure output suggests cylinder bore degradation

Inspection Procedures:

• Visual Examination: During pump overhaul, inspect the cylinder external surface for signs of corrosion, pitting, or mechanical damage

• Bore Inspection (Critical): Each time the high pressure seal assembly is replaced, inspect the cylinder bore for scratches, pits, scoring, or residue buildup. Run a fingernail across the surface to identify imperfections 

• Bore Polishing: If minor surface imperfections are present, polish the inside diameter with 600-grit wet/dry sandpaper using a circumferential wiping motion only. Do not polish along the cylinder length as this may damage the bore surface 

• End Face Inspection: Check the cylinder end face for signs of marking or pitting around the bore edge 

• Thread Inspection: Inspect cylinder threads for signs of wear, galling, or damage. Apply anti-seize compound to threads before installation 

Replacement Guidelines:

• Recommended Service Life: Replace the high pressure cylinder every 3,000 operating hours or immediately if cracking or damage is detected 

• Replacement Indicators: Replace immediately if any of the following are detected :

• Visible cracks or fractures on the cylinder body

• Deep scoring, pitting, or scratching inside the bore

• Out-of-round condition exceeding manufacturer specifications

• Severe corrosion or pitting on sealing surfaces

• Damaged or stripped threads

• Simultaneous Component Replacement: When replacing the HP cylinder, it is recommended to also replace the plunger and all associated high pressure seals to ensure optimal performance 

Installation Best Practices:

• Lubrication: Apply anti-seize compound to cylinder threads and shoulder guides before installation to prevent galling 

• Proper Seating: Carefully thread the cylinder into the hydraulic cylinder head, supporting its weight to prevent thread damage 

• Torque Compliance: Tighten the high pressure cylinder hand tight with the appropriate cylinder wrench, then tap the wrench with the palm of your hand to achieve final tightening 

• Alignment Verification: After installation, place a corresponding alignment mark to ensure proper tightening and full seating

• Full Depressurization: Always fully depressurize the waterjet system and follow lockout/tagout procedures before removing or servicing the HP cylinder