Product Name: O-Ring Backup Ring / O-ring Backring 97 (Part No. 034858/220)

Description:
This component is a precision rigid backup ring (also known as an O-ring backring or anti-extrusion ring) specifically designed for BFT waterjet intensifier pumps . It is manufactured from high-strength, wear-resistant material such as PTFE, PEEK, or reinforced polymer .

The backup ring is a critical sealing support component installed adjacent to an O-ring within a seal groove in the high-pressure cylinder or valve assembly . Its primary engineering function is to provide anti-extrusion support. Under ultra-high pressure operation (up to 60,000-94,000 PSI / 4,137-6,480 bar), the rigid backup ring fills the extrusion gap between the softer O-ring and the metal gland wall, preventing the primary seal from being forced into the clearance gap . This prevents rapid seal failure, pressure loss, and high-pressure water leaks.

According to BFT intensifier parts diagrams for assemblies CP022001/2 and HT022012/172, this backup ring is listed as Item 8 . It works in conjunction with other sealing and retaining components, including retaining rings (S0375x3/103, HT022044/103), piston sealing (XK121/220), wear rings (XF56/220), rod sealing (XST17/220), and other back rings (CP022012/780, CP022015/527) .

Applications:

• Provides anti-extrusion support for O-rings in the high-pressure seal stack of BFT waterjet intensifier pumps 

• Installed in check valve assemblies, seal heads, and the high-pressure cylinder end cover interface

• Used during scheduled preventive maintenance, major pump overhauls, or when external water leakage is detected from the cylinder area

• Suitable for ultra-high pressure waterjet systems operating at 60,000-94,000 PSI (4,137-6,480 bar)

• Compatible with BFT intensifier assemblies CP022001/2 and HT022012/172 

Features:

• Rigid Construction: Made from hard, non-deformable material (PTFE, PEEK, or reinforced polymer) to withstand extrusion forces under extreme pressure 

• Anti-Extrusion Function: Fills the extrusion gap, preventing the softer O-ring from being forced into the gap under high pressure 

• Precision Dimensions: Manufactured to exact tolerances (size 97 specification) for a perfect fit within the designated seal groove

• Critical Consumable Component: Designed for periodic replacement; a worn or missing backup ring leads to immediate seal failure under high pressure 

• Direct OEM Replacement: Listed as Item 8 in BFT intensifier CP022001/2 parts list and Item 8 in HT022012/172 parts list 

• Cross-Reference Compatibility: Interchangeable with back ring part numbers 1-16386 and 034858/220 

Maintenance:

Failure Diagnosis (When to Replace):

• External Water Leakage: Visible water weeping from the high-pressure cylinder weep hole or end cover area indicates seal stack failure, requiring backup ring replacement

• Pressure Drop: Inability to maintain rated cutting pressure suggests internal seal failure, often involving extrusion damage to the O-ring caused by an unsupported gap

• Visible Damage During Disassembly: When the pump is opened for maintenance, inspect the backup ring for signs of deformation, cracking, splitting, flattening, or wear. Any visible damage warrants immediate replacement 

• Scheduled Preventive Maintenance: Standard practice to replace the backup ring together with the O-ring during any scheduled pump maintenance or major overhaul 

• Premature Seal Failure: Frequent failure of O-rings often indicates a worn or missing backup ring allowing excessive extrusion

Inspection and Replacement Guidelines:

• Always Replace with O-Rings: This is a single-use consumable component. Always replace it with a new one whenever the adjacent O-ring is replaced. Do not reuse old backup rings 

• Full Depressurization (Critical): Before any maintenance, place the main electrical disconnect in the OFF position, bleed down all high-pressure lines, and follow lockout/tagout procedures

• Clean Installation: Perform the rebuild in a designated clean area. Thoroughly clean the seal groove and all mating surfaces with a soft, lint-free cloth. Remove all debris, old seal residue, and mineral deposits

• Groove Inspection: Inspect the seal groove for nicks, burrs, sharp edges, or damage that could compromise the seal stack

• Lubrication: Apply a thin, uniform layer of manufacturer-recommended high-pressure grease to the backup ring and O-ring during installation to prevent pinching, rolling, or tearing during assembly 

• Replace as a Set: When servicing the high-pressure sealing stack, it is recommended to replace all components (O-rings, backup rings, and dynamic seals) simultaneously using a complete repair kit

• Cross-Reference Information: This backup ring is also known as 034858/220, O-ring Backring 97, and back ring 1-16386 

Cross-Reference Information:

• BFT #: 034858/220

• Also known as: O-ring Backring 97, O-Ring Backup Ring, Anti-Extrusion Ring, Back Ring 

• Item 8 in Intensifier Assembly CP022001/2 

• Item 8 in Intensifier Assembly HT022012/172 

• Cross-Reference: 1-16386 

• Works with: Retaining Ring (S0375x3/103, HT022044/103), Piston Sealing (XK121/220), Wear Ring (XF56/220), Rod Sealing (XST17/220), Back Rings (CP022012/780, CP022015/527) 

• Rated Pressure: 60,000-94,000 PSI (4,137-6,480 bar)