Ductile Iron DN100-1200mm Gearbox / Pneumatic / Electric Acuator Double Offset Butterfly Valve for Water

Specification

item	Industrial value
Type	double offset butterfly valve
Customized support	OEM
Place of Origin	China
	WENZHOU
Brand Name	TIANYU
Application	General
Temperature of Media	Medium Temperature
Power	Electric
Media	Water
Structure	BUTTERFLY
Product name	double offset butterfly valve
Media	Water Air Liquid
Certificate	ISO
Size	DN50-DN1200
Standard or Nonstandard	ANSI BS DIN JIS GB
Pressure	PN10/PN16
Color	Blue
Temperature	-20°C-120°C
Operation	Worm Gear
Medium	Water Oil Gas

Product Overview

TIANYU Ductile Iron Double Offset Butterfly Valve: An Efficient Solution for Industrial Fluid Control

I. Product Technical Overview

TIANYU double offset butterfly valve is specially designed for fluid regulation and shut-off in industrial pipeline systems. It adopts a double offset sealing structure (dual eccentricity between the stem axis and disc center, as well as the sealing surface centerline), covering DN100-DN1200 (4″-48″) in diameter, suitable for PN10/PN16 (1.0/1.6MPa) and ANSI 125LB/150LB pressure classes, with medium temperature ranging from -20℃ to 120℃ and short-term resistance up to 150℃. The body uses ductile iron, the sealing seat adopts EPDM/NBR rubber, and it supports three drive modes: gearbox, pneumatic, and electric. Widely applied in municipal water supply/drainage, industrial fluid transportation, and building HVAC, it meets the control needs of media such as water, oil, and gas.

II. Core Product Features

(A) Double Offset Sealing Structure Design

The core advantage of TIANYU double offset butterfly valve lies in its geometric offset principle:

Dual Eccentric Design: The stem axis is offset by 1.5mm from the disc center and 1mm from the sealing surface centerline, making the disc completely disengage from the seat after opening 5°, reducing friction and wear. During closing, it gradually compresses the sealing surface with the increase of the angle, forming a self-tightening seal, with a leakage rate ≤5×10⁻⁸m³/s (EN12266 standard).
Low Torque Operation: The opening/closing torque is 30% lower than that of concentric butterfly valves. The gearbox driving torque for DN300 valve is ≤150N·m, adapting to the fast response needs of automation systems.
Wear Resistance: The offset structure avoids direct friction between the disc and seat, extending the service life by 2 times compared to ordinary butterfly valves in sewage with minor particles.

(B) High-Performance Material System

Component	Material	Performance Indicators
Body	Ductile Iron	Tensile strength ≥400MPa, temperature adaptation of -20℃-300℃
Disc	Ductile Iron/Stainless Steel/Aluminum Bronze	Surface roughness Ra≤3.2μm, erosion resistance improved by 40%
Sealing Seat	EPDM/NBR Rubber	Compression set ≤8% (120℃×72h), resistant to chloride ion corrosion
Stem	2Cr13 Stainless Steel	Trapezoidal thread accuracy 6g, quenched and tempered (HB220-250), blowout-proof design

(C) Multi-Scenario Drive System

Gearbox Drive: Speed ratio 1:20-1:40, suitable for torque amplification of large-diameter valves. DN600 valve gearbox opening/closing time ≤30s.
Pneumatic Actuator: IP65 protection level, optional single-acting (spring return)/double-acting, air source pressure 0.4-0.7MPa, response time ≤5s.
Electric Actuator: Supports 4-20mA signal adjustment, positioning accuracy ±1%, compatible with DCS system remote control, with overload protection.

III. Key Technical Attributes

Parameter Category	Technical Indicators	Expansion Options
Size Range	DN100-DN1200 (4″-48″)	Customized DN1400-DN2000 (subject to engineering evaluation)
Pressure Rating	PN10/PN16, ANSI 125/150LB	High-pressure type PN25/PN40 (up to 4.0MPa)
Connection Type	Flange (ANSI B16.5/GB/T 9113)	Wafer-type, welded-type interfaces (according to ISO 5752)
Execution Standards	ISO 5281, EN593, API 609	CE, WRAS, NSF61 (drinking water certification)
Testing Standards	API 598, EN12266	Fire test (API 607), acid corrosion test

IV. Manufacturing Processes and Quality Control

(A) Precision Manufacturing Flow

Body Molding:
- Adopts lost foam casting process. Ductile iron undergoes high-temperature annealing to relieve casting stress, with ferrite content ≥85% in the metallographic structure, ensuring low-temperature toughness (-20℃ impact energy ≥27J).
- Castings are inspected by ultrasonic testing (UT), with surface roughness Ra≤12.5μm and dimensional accuracy reaching CT6 level.
Disc Processing:
- The disc is processed by CNC lathe, with flatness error ≤0.03mm. Stainless steel discs are solution-treated with grain size ≥Grade 6.
- Surface chrome/nickel plating (thickness ≥15μm), passing 500-hour salt spray test without corrosion.
Sealing Assembly:
- Rubber sealing seats are compression-molded, with an interference fit gap with the body ≤0.02mm. Each valve undergoes 1.5x nominal pressure hydrostatic test (30-min hold) and 1.1x air pressure test (helium leak detection).
- Sampled for 100,000 opening/closing life tests, with sealing performance retention rate ≥95%.

(B) Quality Certification System

Material Traceability: Batch numbers of key components can be traced to heat numbers and chemical composition reports, supporting third-party PMI material testing.
System Certifications: Certified by ISO 9001 and CE. Products for drinking water comply with WRAS standards.
Performance Guarantee: Commits to free replacement for leakage caused by process problems within an 18-month warranty period.

Valve Details

VI. TIANYU Brand Customization Advantages

Relying on 20 years of industrial valve manufacturing experience, TIANYU provides end-to-end customized services:

In-Depth Technical Customization: Supports non-standard diameters (such as DN1500), special temperatures (-40℃-180℃), explosion-proof actuators (Ex d IIC T6), and non-standard flanges (DIN/GOST) design, equipped with 3D modeling and CFD flow field analysis.
Efficient Delivery System: 25-day delivery for standard orders, 15-day turnaround for small batch customization (MOQ 1 units), 72-hour emergency channel for urgent orders, with supporting production progress visual tracking.
Global Service Network: 24-month extended warranty, 24/7 response from three major service centers in APAC, Europe, and North America, 48-hour airfreight for critical spare parts, providing digital installation manuals and AR remote debugging support.

Application

V. Product Application Scenarios

(A) Municipal Water Supply/Drainage

In urban water supply networks, TIANYU double offset butterfly valve’s EPDM sealing seat complies with drinking water standards. In a water transmission project of a provincial capital, DN800 valves have been in continuous operation for 3 years under 1.0MPa pressure without leakage, reducing maintenance costs by 50% compared to traditional gate valves. In sewage treatment scenarios, ductile iron bodies are coated with epoxy resin (thickness ≥200μm) for sewage corrosion resistance. DN300 valves have operated continuously for 2 years in sewage with 15% solid content without cleaning.

(B) Industrial Fluid Control

In power plant circulating water systems (PN16/80℃), the double offset structure resists scale deposition, and electric drive response speed ≤3s adapts to the fast shut-off needs during unit start/stop. A chemical plant uses DN500 valves to control ethylene glycol solution, with NBR sealing seats resistant to medium corrosion, achieving 3,000 start/stops without leakage.

(C) Building HVAC Systems

In the air conditioning chilled water pipelines (PN10/70℃) of commercial complexes, gearbox-driven double offset butterfly valves save 40% installation space. An office building project using DN200 valves reduced system energy consumption by 12% compared to traditional valves. Under low-temperature conditions (-20℃), the freeze-resistant ductile iron body ensures stable operation of heating systems.

(D) Oil & Gas Transportation

In oilfield water injection pipelines (ANSI 150LB/60℃), the aluminum bronze disc + NBR sealing seat combination resists crude oil corrosion. An oilfield project uses DN1000 valves to achieve zero-leakage control under high-pressure water injection conditions, reducing water waste.