Product ID: 20475878 – Valve Stem / Needle (Pneumatic On/Off Valve)

Description:
This component is a valve stem, also known as a waterjet needle or pneumatic valve stem, designed for the high-pressure on/off valve assembly in waterjet cutting systems . It is a precision-machined, stem-type sealing component that serves as the moving element within the pneumatic water switch valve body. The valve stem works in conjunction with the valve seat to create a leak-tight seal, controlling the flow of ultra-high-pressure water from the pump to the cutting head . This component is rated for operation up to 90,000 PSI (approximately 6,200 bar) .

Alternative or cross-reference part numbers include 1-14310 and KMT OEM 20475878 . The product weight is approximately 0.008 lbs .

Applications:

• Used as the primary sealing element within the pneumatic on/off valve (water switch) assembly of waterjet cutting systems 

• Installed in the valve body, positioned between the pneumatic actuator (cylinder) and the valve seat, moving up and down to open or close the high-pressure water flow path 

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

• Compatible with KMT AccuStream, Hypertherm, and other standard waterjet systems 

Features:

• Precision-Ground Sealing Surface: Machined to exact specifications for leak-tight shut-off when mated with the corresponding valve seat

• High-Strength Construction: Manufactured from wear-resistant, hardened stainless steel or specialized alloy to withstand repeated impact against the valve seat and high-velocity water flow

• Ultra-High Pressure Rating: Engineered for continuous operation at 60,000–90,000 PSI (4,137–6,200 bar) without deformation or failure 

• Critical Sealing Interface: Functions as the moving sealing element that the pneumatic actuator drives downward to close against the seat, stopping high-pressure water flow

• Pneumatic Actuation Compatibility: Designed to be driven by the pneumatic cylinder mounted above the valve body; the cylinder pushes the valve stem down to close the valve when air pressure is applied

• Consumable Component: The valve stem is a high-wear consumable part designed to protect the more expensive valve body from damage

• Lightweight: Approximate weight of 0.008 lbs for easy handling during maintenance 

• OEM Compatibility: Direct replacement part for KMT AccuStream waterjet systems 

Maintenance:

• Critical Wear Component: The valve stem is a high-wear consumable part. If the stem sealing surface is damaged or worn, the valve will not seal properly, resulting in water leakage from the cutting head when the valve is supposed to be closed, pressure drop, or inability to maintain rated cutting pressure

• Inspection: During pneumatic valve overhaul or preventive maintenance, inspect the valve stem sealing surface for pitting, erosion, cracking, indentation, or mushrooming caused by repeated impact against the seat. Even minor surface damage can cause leakage

• Replacement Criteria: Replace the valve stem immediately if any surface damage is visible. A worn or damaged stem will prevent the valve from sealing properly, leading to water leakage, pressure loss, and reduced cutting performance

• Simultaneous Seat Replacement: When replacing the valve stem, always replace the corresponding valve seat (Product ID 10178697) simultaneously. Reusing a worn seat with a new stem (or vice versa) will compromise sealing and shorten the life of both components

• Water Quality Impact: Poor water quality (contaminants, hardness) accelerates wear on both the valve stem and seat. If these components require replacement too frequently, investigate and improve water filtration/treatment

• Seal Replacement: When servicing the valve, also replace the seal assembly and backup ring as part of a complete valve overhaul

• Actuator Inspection: Inspect the pneumatic actuator (cylinder) for proper operation; a malfunctioning actuator may not fully close the valve stem against the seat, causing leakage

• Full Depressurization: Always fully depressurize the waterjet system (both hydraulic and high-pressure water circuits), shut off compressed air supply, and follow lockout/tagout procedures before removing the valve assembly or replacing the valve stem

• Torque Compliance: When reinstalling, tighten the HP gland and valve body connections to the specific torque values listed in the equipment service manual to ensure proper stem alignment and leak-free operation

• Kit Availability: This valve stem is commonly available as part of pneumatic valve repair kits (water switch maintenance kits), which include the stem, seat, seal assembly, and backup ring for a complete valve overhaul 

• Storage: Store spare valve stems in a clean, dry environment away from impact or abrasive particles to prevent pre-service damage to precision sealing surfaces