Product Name: On/Off Valve Seal Assembly (Part No. 20428052)

Description:
This component is a critical dynamic seal assembly specifically designed for the pneumatic on/off valve (water switch) in high-pressure waterjet cutting systems . It is a pre-assembled unit containing the high-pressure seals, O-rings, and backup rings required to create a leak-tight barrier between the valve stem and the valve body . Rated for continuous ultra-high pressure operation up to 60,000 PSI (approximately 4,137 bar), this assembly is a standard consumable component in waterjet intensifier pumps and on/off valve assemblies .

The seal assembly functions as the primary dynamic sealing element that prevents high-pressure water from bypassing the valve stem when the valve is in the closed position. It is typically positioned between the brass backup ring (10188233) and the valve stem (20435636) within the valve body (10189181) . This component is included in bleed down maintenance kits (e.g., 05116017) for MotoJet pumps and is widely used in KMT, AccuStream, Flow, OMAX, WSI, and Techni waterjet systems.

Applications:

• Provides dynamic sealing for the pneumatic on/off valve (water switch) assembly in waterjet cutting systems 

• Installed in the valve body between the brass backup ring and valve stem to prevent high-pressure water bypass 

• Used during scheduled preventive maintenance or when valve leakage or pressure drop occurs

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

• Compatible with KMT, AccuStream, Flow, OMAX, WSI, and Techni waterjet systems

Features:

• Complete Assembly: Contains all necessary sealing components (high-pressure seals, O-rings, backup rings) for a full valve rebuild 

• Ultra-High Pressure Rating: Engineered for continuous operation at 60,000+ PSI (4,100+ bar)

• Critical Consumable Component: Designed as a high-wear part for periodic replacement during valve service

• Pre-Configured Design: Ensures correct seal orientation and stacking, reducing installation errors

• OEM Quality: Manufactured to meet or exceed original equipment specifications

Maintenance:

When to Replace (Failure Diagnosis):

• Water Leakage from Cutting Head: Visible water dripping from the mixing tube when the valve is supposed to be closed indicates seal failure requiring immediate replacement 

• Pressure Drop: Inability to maintain rated cutting pressure suggests seal degradation or wear

• Scheduled Preventive Replacement: Replace as part of scheduled valve maintenance (typically every 500-1,000 operating hours)

• Bleed Down Valve Service: This seal assembly is a standard component in bleed down maintenance kits (05116017) and should be replaced whenever the dump valve is serviced 

Replacement Guidelines:

• Full Depressurization (Critical): Always fully depressurize the waterjet system (high-pressure water, hydraulic system, and air supply) and follow lockout/tagout procedures before servicing 

• Clean Installation: Perform valve rebuild in a designated clean area to prevent contamination of new seals with abrasive particles

• Replace as a Set: When replacing the seal assembly, also replace the brass backup ring (10188233) and inspect the valve stem (20435636) and valve seat (10178697) for wear 

• Proper Lubrication: Apply manufacturer-recommended high-pressure grease to seals during installation to prevent pinching, rolling, or damage during assembly

• Torque Compliance: When reinstalling, tighten the HP Gland (BV701184) to the specific torque value listed in the equipment service manual 

• Component Orientation: Ensure the seal assembly is correctly oriented in the valve body as shown in the equipment service manual

Cross-Reference Information:

• 20428052

• Included in Bleed Down Maintenance Kit 05116017 

• Compatible with KMT, AccuStream, Flow, OMAX, WSI, and Techni waterjet systems