Product Name: Valve Seat (Pneumatic On/Off Valve) / PN 10178697

Description:
This component is the stationary sealing seat for the pneumatic on/off valve (water switch) assembly in high-pressure waterjet cutting systems . It is a precision-machined disc-shaped component that mates with the valve stem (needle) to create a leak-tight seal, controlling the flow of ultra-high-pressure water from the pump to the cutting head. Manufactured from wear-resistant materials, it is rated for continuous operation at up to 60,000 PSI (approximately 4,137 bar).

This valve seat is a critical internal component of the pneumatic control valve assembly, sitting between the valve body and the valve stem. It is compatible with AccuStream, KMT, Hypertherm, and Techni waterjet systems . Cross-reference part numbers include 1-11099  and 10178697N .

Applications:

• Serves as the stationary sealing surface within the pneumatic on/off valve (water switch) assembly 

• Works in conjunction with the valve stem (20435636) to start and stop high-pressure water flow to the cutting head 

• Suitable for ultra-high pressure waterjet systems (typically 60,000 PSI / 4,137 bar)

• Used in Streamline SL-V, SL-VI (30-50 HP), and SL-V50 series intensifier pumps 

Features:

• Hardened Wear-Resistant Construction: Manufactured from hardened stainless steel to withstand repeated impact from the valve stem and high-velocity water flow 

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

• Reversible Design (Service Life Extension): If one face becomes worn but the opposite face is not, the seat can be reversed, placing the new surface toward the poppet valve. A slight burr at the hole edge identifies the used side 

• Critical Consumable Component: A high-wear part designed for periodic replacement to protect the more expensive valve body 

• Direct OEM Replacement: Interchangeable with OEM part numbers: AccuStream 1-11099, KMT 10178697, and Techni 10178697N 

Maintenance:

When to Replace (Failure Diagnosis):

• External Water Leakage: Visible water weeping from the cutting head when the valve is supposed to be closed indicates seat failure 

• Pressure Drop: Inability to maintain rated cutting pressure may indicate a worn or damaged sealing surface

• Visible Wear During Overhaul: Inspect both faces of the seat for pitting, erosion, cracking, or indentation. Even minor surface damage warrants replacement 

• Scheduled Preventive Maintenance: Replace the seat on a regular schedule; typical recommendation is every 500 pump hours or at the first sign of drip . Routine check valve service is recommended every 1,500 hours 

Inspection and Replacement Guidelines:

• Replace as a Set: The seat, spring, and poppet valve should be replaced together as a set. If one component requires replacement, replace all three 

• Inspect the Seat Carefully: Check for cracks or damage; a cracked or damaged seat must be replaced. If both faces are worn, the seat must be replaced 

• 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. Severe injury can result if the machine is not properly locked out 

• Use Proper Tools: Use two appropriately sized wrenches (typically 1-3/16") to remove the gland nut and access the seat 

• Clean Installation: Perform the rebuild in a designated clean area. Thoroughly clean the valve body cavity and sealing surfaces before installing a new seat

• Lubrication: Apply a thin film of high-pressure grease to the O-rings during reassembly

• Torque Compliance: When reassembling, tighten the gland nut to the torque values specified in the equipment service manual 

• Reverse Worn Seat (Service Life Extension): The seat can be installed with either face toward the poppet valve. If one face is worn but the opposite is not, the seat can be reversed, placing the new surface toward the poppet valve. A slight burr at the hole edge identifies the used side. If both faces are worn, the seat must be replaced 

Cross-Reference Information:

• OEM: KMT #10178697

• Cross-Reference: AccuStream #1-11099 

• Cross-Reference: Techni #10178697N 

• Also known as: Pneumatic Valve Seat, Water Switch Seat

• Component of: On/Off Valve Maintenance Kits (e.g., Flow 001959-1, 010200-1)