Lugged Type Wafer Butterfly Valve LTD371X

Lugged Type Wafer Butterfly Valve LTD371XPurpose

This valve is used as a cutoff and adjusting equipment for the various water supply and drainage pipelines in building chemical, medicine, textile, ship and other industries.

Lugged Type Wafer Butterfly Valve LTD371X Definition and Components

A Lugged Type Wafer Butterfly Valve Model LTD371X is a quarter-turn isolation valve featuring a gear-operated manual actuator mounted on a lugged wafer body. This combination provides mechanical advantage for operating larger valves under pressure while offering the installation flexibility of a lugged design. The "LTD371X" designation typically breaks down as: L = Lugged Body, T = Triple Offset (high-performance) or Thermal Resilient design, 3 = Gear Operator, 71 = Series Designation, X = EPDM Seat.

Main Parts:

• Lugged Body: Ductile iron or stainless steel body with threaded inserts or cast lugs for bolting to flanges.
• Gear Operator (Worm Gear Actuator): Manual handwheel that drives a worm gear to rotate the valve stem, providing high torque output.
• Disc: Offset or eccentric disc (typically stainless steel) designed for wear resistance and tight sealing.
• Resilient Seat (EPDM): An elastomer seat ring that provides bubble-tight shut-off.
• Stem: High-strength stainless steel shaft connecting the gear operator to the disc.
• Position Indicator: Shows disc position (0°, 45°, 90°).
• Stem Seals: Multiple PTFE or reinforced packing rings.
• Threaded Lugs: Allow valve to be bolted to one or both pipeline flanges.

Role, Characteristics, and Application Scenarios of Lugged Type Wafer Butterfly Valve LTD371X in Pipelines

Functions in Pipelines:

• High-Torque Isolation: Provides reliable shut-off for larger pipe sizes (typically DN150/6" and above) where lever operation would be difficult.
• Dead-End Service: Can be bolted to a single flange to isolate branch lines or equipment.
• Flow Regulation: The gear operator allows precise intermediate positioning for throttling applications.
• Bidirectional Sealing: Effective sealing against pressure from either direction.

Operational Features:

• Gear Operator Advantage: Provides 20:1 to 100:1 torque multiplication, making large valves operable by one person.
• Dead-End Service Capability: Rated for pressure on one side with the other side open to atmosphere.
• Position Locking: Most gear operators have provisions for padlocking in any position.
• Durability: Suitable for frequent operation in industrial environments.
• Temperature Range: Limited by EPDM seat (typically -20°C to 120°C).

Common Usage Scenarios:

• Industrial Water Lines: Main isolation valves for cooling water systems.
• Chemical Processing: Moderate chemical service where EPDM is compatible.
• HVAC Systems: Large diameter chilled/heating water lines.
• Fire Protection Systems: Pump discharge isolation.
• Power Plants: Auxiliary water systems.

Lugged Type Wafer Butterfly Valve LTD371X Standards: Materials, Design, and Connections

Material Standards:

• Body: ASTM A536 Ductile Iron (Grade 65-45-12) with epoxy coating, or ASTM A351 CF8M (316SS) for corrosive service.
• Disc: ASTM A743 CA-15 (410 SS) or CF8M (316 SS), often with hardened coating.
• Stem: AISI 316 Stainless Steel or 17-4PH (precipitation hardening).
• Seat: EPDM per ASTM D2000, FDA 21 CFR 177.2600 compliant if needed.
• Gearbox: Cast Iron Housing with Bronze Worm Gear and Steel Worm.

Design & Performance Standards:

• API 609: Primary standard for design and testing.
• ISO 5752: Face-to-face dimensions.
• API 598: Valve inspection and testing requirements.
• Fire Safe Design: API 607/ISO 10497 if required.
• Pressure Rating: Class 150 or PN16 standard. Must specify dead-end pressure rating separately.Connection Standards:
• Lug Design: Threaded for ANSI B16.5 bolt sizes. Common: UNC or 8UN threads.
• Flange Compatibility: ANSI Class 150 raised face flanges.
• Face-to-Face: API 609 or ISO 5752 short pattern.
• Gear Operator Mounting: ISO 5211 mounting pad standard

How to Select Lugged Type Wafer Butterfly Valve LTD371X

Technical Specification Development:

• Service Conditions: Fluid, temperature, pressure (including dead-end requirements).
• Size & Pressure Class: Pipe size (DN200, 8", etc.) and ANSI class.
• Material Specification: Body/disc material, seat type, gearbox material.
• Torque Requirements: Required operating torque based on size/pressure.
• Special Requirements: Fire-safe, cryogenic, or high-cycle needs.

Fire Protection Supply Company Qualification:

• Select manufacturers with API 609 certification.
• Request type testing certificates for fire-safe versions if needed.
• Evaluate gear operator quality - bronze gears preferred over nylon.
• Check dead-end pressure rating certification.

Documentation Requirements:

• Material Test Reports for body, disc, stem.
• API 598 test certificate with seat leakage rate.
• Dimensional drawings for approval.
• Torque charts for gear operator.
• Installation and maintenance manual.

Pre-Shipment Inspection for Export Lugged Type Wafer Butterfly Valve LTD371X and Key Considerations

Visual & Dimensional Inspection:

• Body coating uniformity and thickness (min. 250μm epoxy).
• Lug thread condition - check with go/no-go gauge.
• Gear operator smoothness - handwheel rotation effort.
• Nameplate information completeness.
• Face-to-face dimension verification.

Functional Testing Verification:

• Review API 598 test certificate for:
• Shell test pressure (1.5x rated pressure)
• Seat leakage test (maximum allowable leakage)
• Test duration and medium
• Witness or review video of functional test if possible.

Fire protection water supply Material Certification:

• Mill certificates for metallic components.
• Chemical analysis reports for stainless steel parts.
• Physical property tests for ductile iron.

Lugged Type Wafer Butterfly Valve LTD371X Main part materials

DN	50	65	80	100	125	150	200	250	300
D	125	145	160	180	210	240	295	355	410
N-M	4-M16	4-M16	8-M16	8-M16	8-M16	8-M20	12-M20	12-M24	12-M24
L	43	46	46	52	56	56	60	68	74
H1	70	78	90	102	122	150	174	208	240
H2	199	207	214	241	255	270	309	366	411

Note:1. Other specifications and flange standards are available upon request.

2. Design and specifications are subject to change without prior notice.