Lugged Triple Offset Metal-Seated Butterfly Valve

Description

Triple Eccentric Metal Seated Butterfly Valve Technical Data Sheet
(Lug Type / Triple Offset / High Performance)

1. Product Overview

2. Applicable Standards & Specifications

3. Main Technical Parameters

4. Triple Eccentric Design Principle

The triple eccentric (triple offset) butterfly valve incorporates three distinct offsets that eliminate friction between the disc and seat during operation, providing bubble-tight shut-off and extended service life.

Working Principle:

• Closed Position: Disc contacts seat with uniform compression, providing bubble-tight metal-to-metal seal

• Opening: Disc immediately disengages from seat due to cam action – no sliding friction

• Fully Open: Disc is parallel to flow direction, minimal pressure drop

• Closing: Disc rotates into final closed position, achieving uniform seat compression just before full closure

5. Lug Type Connection Features

6. Material of Construction (Per API 609 / ASME Standards)

6.1 Standard Material Combinations

6.2 Seat / Seal Material Options

7. Structural Features & Working Principle

7.1 Design Features

7.2 Working Principle

• Closed Position: Disc rotated into final closed position; conical sealing surfaces make continuous, uniform contact achieving bubble-tight metal-to-metal shut-off.

• Opening: Due to third offset design, disc immediately disengages from seat upon initial rotation – no sliding friction.

• Mid-Stroke: Disc rotates freely with zero seat contact; minimal operating torque required.

• Fully Open: Disc positioned parallel to flow direction, presenting minimal flow resistance (low pressure drop).

• Closing: Disc rotates toward closed position; only at final moment of closure does seat contact occur, with uniform compression achieved just before full closure.

8. Lug Type Connection Dimensions

8.1 Flange Drilling (Lug Type) per MSS SP-68 / ASME B16.5

Lug type butterfly valves have threaded lugs on both sides of the body, accommodating bolts from upstream and downstream flanges. Standard bolt circle diameters and hole sizes per ASME B16.5.

8.2 Face-to-Face Dimensions per API 609 (Category B – Lug Type)

Class 150 Lug Type Triple Eccentric Butterfly Valve Dimensions

Class 300 Lug Type Triple Eccentric Butterfly Valve Dimensions

9. Testing & Inspection (Per API 598 / ISO 5208)

10. Installation, Operation & Maintenance Instructions

10.1 Pre-Installation

• Remove protective covers, clean valve interior and flange faces

• Verify valve model, pressure class, material, and lug type configuration match service requirements

• Check disc and stem operation for smoothness (90° rotation)

• Inspect flange faces and threaded lugs for any damage

• Ensure disc is in slightly open position during installation to prevent seat damage

10.2 Installation (Lug Type)

• Pipeline Alignment: Ensure pipeline is aligned; misalignment can cause valve body distortion and leakage

• Gaskets: Use appropriate full-face gaskets between flanges

• Bolt Installation: Insert bolts from upstream side through valve lugs and downstream flange; tighten nuts on downstream side

• Bolt Torque: Tighten flange bolts evenly in crisscross pattern to recommended torque

• Dead-End Service: For end-of-line installation, bolts must be fully engaged in threaded lugs on the blind side

• Support: Support piping adequately to avoid stress on valve body (especially for larger sizes)

• Disc Position: Ensure disc does not interfere with pipe ID when opening; verify disc clearance

10.3 Operation

• Opening: Rotate handwheel/actuator counterclockwise (gear) or lever (for wrench-operated) to 90° open position

• Closing: Rotate clockwise to closed position (disc perpendicular to pipe)

• Stop Adjustment: Ensure gear operator or actuator stops are properly adjusted to prevent over-travel

• Operating Torque: Do not exceed recommended operating torque; use gear operator for larger sizes

• Periodic Operation: Operate valve monthly to prevent seat sticking, especially in high temperature service

10.4 Maintenance

• Packing Adjustment: If slight stem leakage occurs, evenly tighten gland nuts (do not over-tighten)

• Packing Replacement: Can be performed with valve in service (if backseat is functional)

• Seat / Disc Inspection:

  • Depressurize valve completely before disassembly

  • Remove valve from pipeline

  • Inspect seat ring and disc sealing surfaces for wear, scoring, or damage

  • Measure seat contact pattern (uniform around circumference)

• Seat Replacement (if applicable):

  • Remove seat retaining ring/screws

  • Replace seat ring (original manufacturer recommended)

  • Reassemble and perform leak test

• Stem Seal / Bushing Replacement: Replace if excessive play or leakage is observed

• Lubrication: Gear operators require periodic lubrication per manufacturer’s instructions

• Spare Parts: Recommended spare parts include seat ring, gaskets, stem seals, bushings, and packing

11. Ordering Information

When ordering Lug Type Triple Eccentric Metal Seated Butterfly Valves, please specify:

12. Available Options

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Note: This technical data sheet is a general guideline for Lug Type Triple Eccentric Metal Seated Butterfly Valves, compliant with API 609 Category B, ASME B16.34, and related standards. The triple eccentric design ensures zero friction operation, bubble-tight shut-off, and extended service life for demanding applications. Lug type connection allows dead-end service and downstream piping removal for maintenance. For specific project requirements, including detailed dimensions, material selection, pressure class, and special service conditions, please refer to the approved manufacturer’s drawing and purchase order. Specifications are subject to change without notice.