Specification

DN100 PN16 Lug Type Double Disc Swing Check Valve

I. Product Overview

TIANYU lug type double disc swing check valve is a high-performance flow control device designed to prevent reverse flow in industrial pipelines. Featuring a dual-disc structure and lug-type connection, it combines compact design with reliable non-return functionality. Constructed from diverse materials (carbon steel, stainless steel, alloys) to suit media properties, it complies with international standards like API 594 and ANSI B16.10. Ideal for handling water, steam, oil, and corrosive fluids, it ensures system safety and efficiency across metallurgy, power, petrochemical, and light industrial sectors.

II. Key Attribute Parameters

Size Range: 2″~60″ (DN50~DN1500), covering small to extra-large pipelines to meet flow requirements in equipment lines, main transmission networks, and industrial loops.
Pressure Rating: 150LB~2500LB (PN16~PN420), with PN16 (1.6MPa) as a common specification, adapting to low, medium, and high-pressure systems.
Temperature Range: -196℃~540℃, varying by material—e.g., stainless steel (304/316) for cryogenic to moderate high temps; alloy steel (WC6/WC9) for 540℃ high-temperature steam.
Material Configuration:
- Body: Carbon steel (WCB), stainless steel (CF8/CF8M), duplex stainless steel, or alloys (Monel, Alloy 20) for corrosion resistance.
- Disc & Seat: Renewable split discs (stainless steel/bronze) with precision sealing surfaces; seats matched to body material for tight contact.
- Trim: Pins and hardware in corrosion-resistant materials (316 stainless steel) to avoid jamming.
Connection Type: Lug-type (compatible with flange pipelines per ANSI B16.5/16.47), enabling installation in any orientation (horizontal/vertical) without disconnecting pipelines.
Standards Compliance: Design per API 594; face-to-face dimensions per ANSI B16.10; testing per API 598; certified with ISO 9001, CE, API 6D for quality assurance.

Product Overview

III. Structural Features

Double Disc Design: Two symmetrical discs swing on a central pin, reducing closing impact and minimizing water hammer—critical for protecting pipeline components from pressure surges. The discs automatically close under reverse flow, ensuring tight shut-off.
Lug-Type Construction: Threaded lugs on the valve body allow direct bolting to pipeline flanges, eliminating the need for separate gaskets between valve and flange. This simplifies installation and enables in-line maintenance.
Zero External Leakage: Precision-machined body and gland packing (graphite/PTFE) prevent external leakage, meeting environmental and safety requirements in hazardous media applications (e.g., oil, toxic fluids).
Renewable Discs: Split disc design allows easy replacement without removing the valve from the pipeline, reducing maintenance downtime and extending service life.
Corrosion Protection: Internal and external epoxy coating (for carbon steel bodies) resists rust and chemical erosion, enhancing durability in humid or corrosive environments (e.g., wastewater treatment).

IV. Manufacturing Processes

Raw Material Inspection: Materials undergo spectral analysis to verify chemical composition (e.g., CF8: 18-20% Cr, 8-10.5% Ni) and ultrasonic testing to eliminate internal defects (cracks, inclusions).
Precision Machining:
- Body & Lugs: CNC lathes machine lug holes to ±0.1mm tolerance for flange alignment; sealing faces are ground to flatness ≤0.05mm for tight flange connection.
- Discs & Pins: Dual discs are CNC-machined to ensure symmetry, with sealing surfaces lapped to Ra ≤1.6μm for uniform contact; pins are polished to reduce friction during swing.
Surface Treatment: Carbon steel components receive epoxy coating (dry film thickness ≥100μm) after sandblasting (Sa 2.5); stainless steel parts are passivated to enhance corrosion resistance.
Assembly & Testing:
- Discs are mounted on pins with proper clearance to ensure smooth swing (no jamming); gland packing is torqued to specification for zero external leakage.
- Each valve undergoes API 598 testing: hydrostatic shell test (1.5×rated pressure) and reverse pressure test (1.1×rated pressure) to verify non-return functionality and tightness.

Valve Details

V. Product Advantages

Effective Reverse Flow Prevention: Dual discs close rapidly under reverse pressure, minimizing backflow volume and water hammer—protecting pumps, meters, and pipeline fittings from damage.
Flexible Installation: Lug-type design allows mounting in horizontal, vertical, or inclined pipelines, adapting to space constraints in industrial layouts.
Low Maintenance: Renewable discs and split structure enable in-line repair, reducing downtime by 50% compared to one-piece check valves; corrosion-resistant coatings extend service intervals.
Broad Media Compatibility: Diverse materials (alloys, duplex stainless steel) handle corrosive fluids (acids, seawater), high-temperature steam, and viscous oils, suiting multi-industry applications.
Cost-Efficient: Compact design reduces material usage; lug connection eliminates need for extra gaskets, lowering installation costs while maintaining performance.

Application

VI. Application Fields

Power Generation: Protects boiler feed lines, condensate systems, and turbine cooling loops from reverse flow of high-temperature steam, ensuring stable operation of power equipment.
Petrochemical Industry: Controls non-return of crude oil, refined products, and chemical intermediates in storage tank outlets, transfer pipelines, and reactor feed lines.
Metallurgy: Manages water, steam, and cooling fluids in steel mill rolling lines and smelting processes, preventing contamination from backflow.
Water & Wastewater Treatment: Prevents reverse flow in pump discharge lines, filtration systems, and distribution networks, maintaining process integrity.
Light Industry: Used in food processing (clean water), textile (steam), and paper mill (chemical solutions) pipelines, ensuring product quality and equipment safety.