Product Name: Seal Buttress (Part No. 20457990) – Intensifier Component

Description:
The Seal Buttress (P/N 20457990) is a critical precision-machined component within the high-pressure seal stack of a waterjet intensifier pump. Listed as a sub-component of Rebuild Kit 20458773 in parts diagrams, it serves as a rigid supporting ring (or back-up ring) specifically engineered to prevent extrusion of the dynamic high-pressure (HP) seal under extreme operating pressures .

In high-pressure applications (typically 60,000-94,000 PSI / 4,137-6,480 bar), the softer elastomeric HP seal is subject to deformation. The Seal Buttress provides a solid mechanical shoulder that supports the seal, filling the radial gap between the plunger and the cylinder wall. This prevents the HP seal from being forced (extruded) into the clearance gap, which would otherwise cause rapid seal failure, pressure loss, and high-pressure water leaks . It is part of the high-pressure seal assembly, working in conjunction with the HP Seal (20458113), Seal Hoop (20457393), and O-Ring (20460108).

Applications:

• Installed within the high-pressure cylinder assembly (Intensifier Assembly 20458728) between the End Bell and the High Pressure Cylinder .

• Positioned behind the primary dynamic HP seal to provide anti-extrusion support.

• Used during scheduled preventive maintenance or when symptoms of seal failure (water leakage, pressure drop) appear.

• Suitable for 60,000-94,000 PSI ultra-high pressure waterjet intensifier systems (compatible with KMT, H2O Jet, AccuStream).

Features:

• Precision ID Tolerance: The internal diameter (ID) is precision-machined to a tight tolerance, which keeps the HP seal from extruding between the plunger and the buttress, ensuring a long seal life .

• Grooved Design: Features unique grooves on the outside edge, allowing for easy gripping and removal with standard tools during seal replacement .

• Rigid Structural Support: Provides a non-deformable backing to the elastomeric seal under extreme pressure, preventing extrusion and blow-out.

• Critical Wear Component: While more durable than the seals themselves, the buttress can wear over time and requires inspection during major overhauls.

• Crack Inspection: The flange area is a critical inspection point for stress cracks during maintenance .

Maintenance:

Failure Diagnosis (When to Inspect/Replace):

• During HP Seal Replacement: The Seal Buttress should be removed and inspected every time the HP Seal assembly (P/N 20458773) is serviced .

• Inspect for Cracks: Wipe and clean the surfaces, weep holes, and grooves of the Seal Buttress flange thoroughly; check the flange specifically for cracks . A cracked buttress will fail to support the seal properly.

• Visible Wear or Deformation: Inspect the contact surfaces for scoring, galling, or uneven wear. If the sealing face is damaged, it must be replaced.

• External Water Leakage: Water weeping from the high-pressure cylinder area may indicate that the seal buttress is not properly seated or has failed.

Inspection and Replacement Guidelines:

• 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.

• Disassembly:

1. Remove the High Pressure Cylinder following the manufacturer's recommended procedure. The High Pressure Cylinder is heavy and must be supported to avoid damaging the plunger or causing injury .

2. Once the cylinder is removed, the high pressure seals and the seal buttress can be accessed.

3. Remove the Seal Buttress from the End Bell.

• Cleaning: Clean the buttress thoroughly. Ensure all debris, old seal residue, and mineral deposits are removed from the grooves and surfaces .

• Replacement Criteria: Replace the Seal Buttress immediately if cracks are found, if the precision internal diameter is worn, or if the sealing surfaces are damaged.

• Reassembly: When installing the new seal buttress and HP seals, ensure the components are correctly oriented (e.g., the chamfer orientation). Refer to the specific equipment service manual for the correct stacking order.

• Lubrication: Apply a light coat of high-pressure grease to the new seals and mating surfaces during installation.

Cross-Reference Information:

• H2O Jet / KMT #: 20457990

• Part of Rebuild Kit, High Pressure Seal Assembly (20458773)

• Intensifier Assembly (20458728)

• Typically serviced with: HP Seal (20458113), Seal Hoop (20457393), O-Ring (20460108)