NOV Varco 718636 Repair Kit | 3″ 15M T-B Valve Spare Parts

NOV 718636 Repair Kit for 3″ 15M T-B Valves

The National Oilwell Varco (previously Varco) NOV 718636 Repair Kit is a high-performance, precision-engineered array of replacement parts. This premium service kit is specifically designed for the complete overhaul and maintenance of 3-inch nominal diameter, 15,000 PSI (15M) Top-Entry (T-B) check and mud valves used in demanding offshore drilling rigs, marine vessel mud manifolds and high pressure well service operations.

This kit is designed to provide absolute pressure integrity to worn components and to limit the potential for severe fluid erosion and dangerous backflow downstream of high pressure portable treatment iron and standpipe systems. It contains a complete set of elastomeric seals, structural gaskets and dynamic components for a standard 2-year major service interval.

Model Details:

• Manufacturer: National Oilwell Varco (NOV)
• Manufacturer Product Number (MPN): 718636
• Equipment Application: 3″ 15M T-B Valve (3-15M T-B VLV 2YRS SVC)
• Alternative Identification: Varco 718636 Spare Part Kit

Technical Specifications: NOV 718636 Repair Kit

Key Features

1. 15,000 PSI Certified Integrity: All seals and sealing gaskets within the kit are rated for up to 15M maximum working pressure configurations, absorbing extreme pulsations without deformation.
2. Complete 2-Year Overhaul Array: Includes all critical non-metallic soft components and wear seals required for a full turnaround, significantly maximizing uptime intervals.
3. High-Dampening Bonnet Ring Gasket: Features the specific yellow TFC 20021676 high-pressure bonnet seal ring designed to accommodate thermal expansion cycles under massive structural bolt loads.
4. Superior Abrasion Resistance: Polyurethane and specialized elastomer profiles resist hard proppant particles, cement slurries, and chemically aggressive drilling polymers.
5. In-Situ Maintenance Compatibility: Configured specifically for Top-Entry (T-B) designs, allowing rapid internal component swap-outs without isolating the physical valve body from the manifold line.

Part Number Cross-References

• NOV / Varco Part ID: 718636
• Bonnet Seal ID: TFC 20021676
• Alternative Kit Descriptors: 3-15M T-B VLV 2YR SVC KIT

Industrial Applications

• Offshore Rig Drilling Mud Circuit Overhauls: Preventing backflow into positive displacement mud pumps during deep-well drilling operations.
• Well Stimulation & Cementing Lines: Isolating upstream pumping trucks from lethal pressure spikes when pumping high-viscosity proppants or acidic fluids.
• Coiled Tubing Blowout Preventer (BOP) Support Systems: Providing auxiliary isolation security during complex downhole well intervention operations.

Marine Chief Engineer’s Maintenance Guide:

• Storage Environment Matters: High-pressure oilfield elastomers are highly sensitive to ultraviolet light and ozone decay. Keep this kit sealed in its anti-static, dark packaging until the exact moment of deployment to prevent micro-fissures in the HNBR compounds.
• Sequential Bonnet Torquing: The yellow TFC 20021676 ring gasket relies on precise, symmetrical deformation. Always use a calibrated hydraulic torque wrench to tighten the top bonnet studs in a progressive “star pattern” method. Uneven stud tension will instantly warp the ring seal, causing high-pressure failure during line pressure testing up to 15,000 PSI.