Specification

TIANYU Cryogenic Butt Weld Manual Butterfly Valve: A Reliable Solution for Industrial Low-Temperature Fluid Control

I. Product Technical Positioning

The TIANYU cryogenic butt weld manual butterfly valve is specially designed for low-temperature applications ranging from -40°C to -196°C, featuring a triple-offset sealing structure (offsets between stem axis, disc center, and sealing surface centerline). Constructed with ductile iron (DI) and cast iron (CI), it suits cryogenic media like water, liquefied natural gas (LNG), and liquid nitrogen. The valve connects to pipelines via butt weld ends, combined with a manual worm gear drive, meeting cut-off and regulation needs in water treatment, oil & gas storage, and air separation equipment. Certified to ISO 9001, CE, and WRAS for drinking water safety, it balances safety and reliability.

II. Core Product Features

(A) Cryogenic Adaptation Design

Low-Temperature Material Toughness:
The body uses ductile iron QT450-10 (impact energy ≥27J at -40°C) or cast steel WCB (impact energy ≥27J at -29°C), while the stem employs 17-4PH stainless steel (tempered for -196°C brittleness resistance), ensuring structural stability in cold environments.
Anti-Freeze Sealing System:
The seat uses VITON fluoroelastomer or PTFE, maintaining elasticity from -60°C to 200°C. With spring-loaded pre-tensioning, it compensates for material shrinkage at low temperatures, achieving a leakage rate ≤1×10⁻⁸m³/s (EN 12266).

(B) Triple-Offset Sealing Structure

Zero-Friction Operation:
The triple-offset design disengages the disc from the seat within 5° of opening, eliminating wear. Opening/closing torque is 35% lower than concentric valves, with DN300 valves requiring ≤80N·m for manual operation—ideal for cold-weather human operation.
Metallic Hard Seal Redundancy:
The disc seat is overlaid with Stellite 6 alloy (≥2mm thickness), hardness HRC45-50, providing metal-to-metal sealing if soft seals fail. It meets API 607 fire test requirements (leakage ≤0.01L/min·mm during fires).

(C) Butt Weld Connection Advantages

Welding Strength Assurance:
Butt weld ends comply with ASME B16.25, with a 37°±2° bevel angle. Post-welding 100% radiographic testing (RT) ensures crack-free joints for pressure pipelines (PN10-PN40).
Leak-Free Installation:
Welded connections eliminate flange gasket leaks, critical for LNG pipelines (-162°C), reducing potential leakage points by 80% versus flanged connections.

III. Key Technical Attributes

Parameter Category	Technical Indicators	Expansion Options
Nominal Size	DN50-DN600 (2″-24″)	Custom DN700-DN1200 (engineering evaluation)
Pressure Rating	PN10-PN40 (1.0-4.0MPa)	Class 150-Class 600 (ASME standards)
Temperature Range	-40°C~-196°C (standard)	Ultra-cryogenic -270°C (Inconel 625 material)
Connection Type	Butt Weld	Flanged, socket weld (customizable)
Actuation	Manual Worm Gear (standard)	Electric/pneumatic actuators (IP68 protection)
Sealing Standards	API 598, EN 12266	Fire certification API 607, BS 6755

Product Overview

IV. Manufacturing Processes and Quality Control

(A) Precision Manufacturing Flow

Cryogenic Material Treatment:
- Ductile iron bodies undergo -40°C cryogenic annealing to relieve casting stress, with graphite controlled as Type A (spheroidization rate ≥90%). Stainless steel components receive deep cryogenic treatment (-196°C×24h) to stabilize martensite and prevent low-temperature phase changes.
Seat Surface Machining:
- Disc seats are processed via 5-axis CNC grinding, with flatness error ≤0.01mm and roughness Ra≤0.8μm. Stellite alloy overlay is ultrasonically inspected for porosity after welding.
Assembly and Testing:
- Each valve is tested in a -40°C environmental chamber, undergoing 1.5x nominal pressure hydrostatic testing (30-min hold) and 1.1x air pressure leakage testing (helium mass spectrometry). Sampled valves complete 100,000 cycle life tests (seal performance retention ≥95% at low temperatures).

(B) Quality Certification System

Material Traceability: Key components include heat numbers and CMA-certified chemical reports, supporting third-party PMI testing.
System Certifications: Holds ISO 9001, CE-PED, WRAS (drinking water), and marine certifications (LR, DNV-GL) for ship applications.
After-Sales Guarantee: 18-month warranty covers leakage due to material defects under cryogenic conditions.

Valve Details

VI. TIANYU Brand Customization Advantages

TIANYU offers end-to-end customization from its WENZHOU smart manufacturing base:

Material Deep Customization: Supports special alloys like Inconel 718 and Hastelloy C276 for -270°C ultra-cryogenic or corrosive media, providing low-temperature mechanical property reports and simulation data.
Drive System Expansion: Integrates explosion-proof electric actuators (Ex d IIC T6) or pneumatic actuators (with low-temperature cylinder lubrication) for automation, offering 3D modeling and flow analysis.
Rapid Delivery System: 25-day standard lead time, 15-day small-batch customization (≥1 units), and 72-hour emergency channels with production tracking.
Global Service Network: Three technical centers in North America, Europe, and APAC provide installation guidance, maintenance training, and 24/7 emergency response, with critical spares delivered within 48 hours via airfreight.

Application

V. Product Application Scenarios

(A) Water Treatment and Drinking Water

In municipal low-temperature water supply systems (e.g., northern winter pipelines, -20°C), WRAS-certified EPDM seats ensure water safety, while butt welds prevent freeze cracking. A northern city water plant used DN400 valves for 2 years at -30°C without leakage, reducing maintenance costs by 40% versus flanged valves.

(B) Liquefied Natural Gas (LNG)

In LNG terminal BOG (boil-off gas) pipelines (-162°C, PN40), the triple-offset metallic seal meets zero-leakage requirements. The manual worm gear drive operates smoothly at low temperatures. A coastal LNG project used DN600 valves with SIL2 functional safety certification, achieving emergency shut-off in ≤10 seconds.

(C) Air Separation Units

In liquid nitrogen pipelines (-196°C, PN25) of air separation plants, butt welds ensure cryogenic tightness, and cast steel bodies resist deep cold embrittlement. A steel plant air separation workshop used DN200 valves with low-temperature instrument air systems for precise oxygen-nitrogen separation control.

(D) Marine and Offshore Engineering

In low-temperature ballast water systems (-40°C) of ocean-going cargo ships, classification society-certified valves pass vibration tests (ISO 10816). Butt welds adapt to ship swaying. A container ship installed DN300 valves, withstanding -35°C in Arctic routes without leakage.