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Full Lined PTFE Butterfly Valve

October 18, 2025

What is a Full Lined PTFE Butterfly Valve?

A full-lined PTFE butterfly valve is a butterfly valve whose wetted (fluid-contact) surfaces (body interior + disc / plate + sometimes stem bushing, etc.) are fully lined with PTFE (Polytetrafluoroethylene) or a similar chemically inert fluoropolymer. The lining protects the metal against corrosion and chemical attack. Useful for acids, alkalis, aggressive chemicals, etc.
Key features often include:
Full PTFE lining: Body & disc (sometimes liner also for shaft sealing) so that the medium does not contact the metallic parts.
Valve types: Wafer, Lug, Flanged, split-body, two-piece body, etc.
Pressure ratings: Commonly PN10, PN16, ANSI 150 / Class 150, sometimes lower / higher depending on size & design.
Size range: From small (DN50 / 2″) up to large (DN600, DN1200 etc) depending on manufacturer.
Temperature range: Depends on PTFE and other materials. Usually −20°C up to about +150°C (sometimes more, sometimes less).
Body and disc materials: Stainless steel, cast iron, ductile iron, carbon steel, etc, but protected by the PTFE lining.

Pros & Cons

Pros	Cons / Limitations
Excellent chemical resistance (acids, alkalis, corrosives)	PTFE lining adds cost; thick lining can reduce opening torque / increase weight in large sizes.
Non-stick, easy cleaning, long life in aggressive media	Limited temperature range (PTFE softens above certain temps / creep can be issue at high temp and load).
Good sealing (if well designed)	Mechanical strength of valve body still matters; PTFE can deform under high pressure differential if design not proper.
Can prevent metal contamination for purity/clean fluid applications	Repair/lining replacements can be more complex than unlined types.

What to Check / Ask For When Buying
If you are selecting a supplier or model, consider:
1.Lining quality & method
How is the PTFE liner attached (bonded, mechanically fixed)?
Is the disc also lined or just the body?
2.Pressure & temperature ratings
At your operating temperature & pressure, is the PTFE specification valid? (PTFE has limits).
Overpressure, vacuum capability.
3.Standards & test certificates
Compliance: API609, EN593, EN12266, ISO5752, ANSI, etc.
Leakage class, tightness tests.
4.Connection type
Wafer, lug, flange types. Which suits your piping system.
5.Actuation
Manual lever, gear, pneumatic, electric. Torque required (PTFE adds friction sometimes).
6.Maintenance
Can the liner/disc be replaced or serviced? Spare parts available.
Expected lifetime under your fluid & environment.
7.Chemical compatibility
The specific chemicals, concentration, temperature, etc. Make sure PTFE is compatible.

C95200 Aluminum Bronze Disc for Centric Butterfly Valves

September 28, 2025

1. Material Description
Grade: C95200
Alloy Name: Aluminum Bronze
Main Chemical Composition:
Cu ≈ 85% Al ≈ 10% Fe ≈ 3–4% Ni/Mn: trace elements
Standards: ASTM B148 / B584
Key Properties: High strength, excellent wear resistance and outstanding corrosion resistance in seawater and mildly corrosive environments.
2. Product Features
Seawater Corrosion Resistance – Exceptional performance in marine and offshore conditions.
High Mechanical Strength – Higher tensile and yield strength compared to tin bronze, suitable for demanding applications.
Excellent Wear Resistance – Ensures long-term sealing stability under frequent opening and closing.
Soft-Seat Compatibility – Works with EPDM, NBR, Viton and other elastomers for zero-leakage sealing.
3. Applications
Marine centric (soft-seated) butterfly valves.
Ballast water, seawater cooling, fire-fighting, desalination and other pipeline systems.
Ports, docks, offshore platforms and chemical plants requiring corrosion-resistant piping.
4. Specifications
Size Range: DN50 – DN1200 (or per customer drawing).
Pressure Ratings: PN10 / PN16 / Class 150.
Design Options: Pin and pinless disc structures available.
Surface Finish: Precision machined and polished; optional anti-rust coating.
5. Quality Assurance
100% spectrographic analysis of raw materials.
Radiographic/ultrasonic testing of castings and hydrostatic tests.
Dimensional accuracy and surface roughness in compliance with international standards.
6. Supply & Customization
OEM/ODM production according to customer drawings or samples.
Logo or marking customization available.
English technical documents, 3D drawings and export packaging provided.

C83600 Concentric Butterfly Valve Disc – Detailed Introduction

September 15, 2025

1. Material Description

C83600 belongs to Leaded Tin Bronze, one of the internationally recognized and widely used materials for marine valves.

Main Composition:

Copper (Cu): ~83%

Tin (Sn): ~7%

Lead (Pb): ~7%

Zinc (Zn): ~3%

Standards: Complies with ASTM B62, SAE 40

Material Properties:

High strength and toughness

Excellent corrosion resistance, especially suitable for seawater and salt spray environments

Superior casting performance and machinability

Good self-lubricating ability and excellent anti-galling performance

2. Advantages in Butterfly Valve Discs

Seawater Corrosion Resistance
C83600 maintains stable corrosion resistance in chloride-rich seawater, preventing pitting or dezincification of the disc.

Stable Sealing Performance
The disc has a high surface finish and good machinability, ensuring a precise fit with soft seats such as EPDM and NBR, and guaranteeing zero or minimal leakage.

Wear and Erosion Resistance
Under frequent operation or high-velocity seawater flow, discs made of C83600 offer long service life and are resistant to wear and erosion.

Excellent Castability and Machinability
Suitable for casting complex disc structures, with dense microstructure and high machining precision, ensuring overall valve performance.

High Reliability
Meets the requirements of classification societies such as ABS, LR, DNV, BV, and is widely used in marine systems.

3. Applications

C83600 discs are widely applied in concentric soft-seated butterfly valves for marine service, with typical applications including:

Ballast Water Systems

Seawater Cooling Systems

Fire-Fighting Piping Systems

Bilge, sewage, and seawater pipelines

4. Typical Properties

Property	Value Range	Remarks
Tensile Strength	≥ 250 MPa	Ensures strength and load capacity
Yield Strength	≥ 100 MPa	Resistant to deformation under load
Brinell Hardness (HB)	65 – 85	Balanced hardness for wear resistance and machinability
Elongation	≥ 10%	Provides toughness and impact resistance
Density	~ 8.8 g/cm³	Dense and stable material structure
Corrosion Resistance	Excellent	Especially suitable for marine environments

Bronze Disc for Butterfly Valve

September 4, 2025

Product Description

The bronze disc is one of the key components of a butterfly valve, mounted inside the valve body and connected with the stem and seat to control on-off and flow regulation. Manufactured from high-quality bronze alloys, the disc provides excellent corrosion resistance and mechanical strength, making it especially suitable for seawater, brine, and mildly corrosive environments.

1，Materials

C95400，C95500，C95800，C83600，RG102，Typical materials include:

C95400 Aluminum Bronze，C95500/C95800 Nickel Aluminum Bronze

C83600 Cast Bronze，RG10 Naval Bronze

3，Features & Advantages

Excellent corrosion resistance for seawater and saline environments

High strength and toughness for reliable long-term operation

Wear resistance for extended valve service life

Precision casting ensures perfect sealing with the valve seat

4，Applications

Marine piping systems (ballast water, cooling water, fire-fighting lines)

Desalination plants

Offshore engineering platforms

Brine and chemical pipelines

Concentric Type Butterfly Valve with Pin and Pinless

August 22, 2025

Concentric Butterfly Valve with Pin

Structure: The disc is fixed to the stem by pins, ensuring direct and reliable connection.

Advantages:

Simple manufacturing process and easy assembly.

Reliable torque transmission between the disc and the stem, not easy to slip.

Suitable for larger torque and frequent open/close operations.

Disadvantages:

Pin holes may become corrosion points, especially in seawater or corrosive media.

Possible leakage through pin holes.

Not as precise or tight as pinless design in high sealing requirements.

Concentric Butterfly Valve without Pin (Pinless)

Structure: The disc is fixed to the stem by interference fit, keyway, or integral casting, without using pins.

Advantages:

Eliminates pin holes, reducing leakage risk.

Better corrosion resistance, especially suitable for marine, seawater desalination, and offshore applications.

Stronger integrity between disc and stem, cleaner appearance.

Disadvantages:

Higher manufacturing and assembly precision required.

Maintenance is more complex if the connection loosens.

Generally higher cost than pinned design.

With Pin → Traditional design, lower cost, suitable for general conditions.

Pinless → Better corrosion resistance and sealing performance, more suitable for marine use and high-end markets.

Installation Locations of Dual-Plate Check Valves on Ships

August 8, 2025

Dual-plate check valves are mainly installed in pipelines where the medium flows in one direction, preventing backflow and reducing water hammer impact. On ships, typical installation locations include:

1. Engine Room Systems

Main Seawater Cooling System
Installed between the sea chest valve and the seawater pump, or between the pump outlet and the cooler, to prevent seawater from flowing back when the pump stops.

Freshwater Cooling System
Located at the outlet of the cooler to prevent backflow of cooling water to the equipment.

Fuel and Lube Oil Cooling Systems
Installed at the cooler or pump outlet to prevent oil from flowing back after the pump stops.

2. Ballast and Tank Systems

Ballast Water System
Between the ballast pump outlet and the ballast tanks to prevent water from flowing back, especially in systems with multiple pumps or tanks where each branch line needs a check valve.

Tank Drain Systems
To prevent liquid from one tank from flowing into another.

3. Firefighting and Emergency Systems

Firefighting System
At the outlet of the fire pump or branch lines to prevent backflow to the pump or other systems.

Emergency Pump Systems
To prevent cross-flow between the emergency pump and the main pump.

Installation Notes:

Can be installed horizontally (shaft vertical) or vertically (flow upward).

Should be located close to the pump outlet to minimize backflow and water hammer.

The arrow on the valve body must align with the flow direction of the pipeline.

Installation Locations of Concentric Butterfly Valves in Marine Applications

July 29, 2025

Concentric butterfly valves, also known as centerline butterfly valves, are widely used in marine piping systems due to their compact structure, light weight, quick operation, cost efficiency, and adaptability to various media. Below are the typical installation positions and application systems on ships:

Common Installation Locations & Applications

Ballast Water System

Installed between ballast tanks and ballast pumps.

Used to control seawater intake and discharge, adjusting ship stability and draft.

Cooling Water Systems (Seawater/Freshwater)

Installed on inlet/outlet pipes of engines, condensers, and heat exchangers.

Controls the flow of cooling water, ensuring efficient heat dissipation.

Bilge System

Located at the suction lines of bilge pumps or branch pipelines.

Manages bilge water discharge from different compartments.

Sanitary and Sewage Systems

Installed between sewage holding tanks and treatment units.

Ensures safe flow control and maintenance isolation.

Ventilation and HVAC Systems

Mounted in ventilation ducts to regulate or shut off airflow.

Ideal for confined spaces with limited installation clearance.

Fuel and Lubricating Oil Systems

Applied in low-pressure areas for oil flow control and emergency shut-off.

Suitable for non-critical and low-temperature locations.

Deck Service Lines (e.g., Fresh Water, Tank Washing Water)

Installed on deck piping systems to manage service fluid distribution.

Found under deck, in passageways, or utility corridors.

Installation Notes for Concentric Butterfly Valves

Recommended positions: Mid-pipeline or near the equipment inlet/outlet.

Shaft orientation: For horizontal pipelines, it’s advised to install with the shaft vertical (disc horizontal).

Ease of maintenance: Ensure installation allows for convenient access.

Suitable media: Seawater, freshwater, air, sewage, light oil, and other non-corrosive or mildly corrosive fluids.

Difference Between Low Temperature Valves and Normal Temperature Valves in Marine Applications

July 22, 2025

In marine valve applications, low temperature valves and normal temperature valves are designed for different working conditions. Their main differences are as follows:

Operating Temperature Range

normal temperature valves are designed for media with temperatures ≥ -29°C (e.g. seawater, freshwater, fuel oil, compressed air).

Low temperature valves are designed for extremely low temperatures ≤ -29°C, such as -46°C, -101°C, -196°C, used for LNG, LPG, liquid nitrogen, etc.

Material Selection

normal temperature valves use conventional materials like carbon steel (WCB), stainless steel (CF8/CF8M), or bronze.

Low temperature valves require special low-temperature-toughness materials, such as:

Low-temperature carbon steel (LCB, LC2)

9% Nickel steel

Austenitic stainless steel (304, 316L)

Aluminum alloy, Monel alloy

These materials maintain ductility and toughness at Low termperature temperatures, preventing brittle failure.

Structural Design

Normal temperature valves have standard designs without special considerations for thermal contraction.

Low temperature valves incorporate:

Extended bonnet (to keep packing away from the cold zone)

Special low-friction sealing materials suitable for low temperatures

Designs that minimize leakage and avoid jamming due to thermal contraction

Testing Requirements

Normal temperature valves are tested according to standard marine class rules (e.g. API, ISO, CCS, LR).

Low temperature valves undergo additional tests, such as:

Impact test at Low temperature temperature

Low-temperature sealing and functional tests

Typical Applications

Item	Normal temperature Valves	Low temperature Valves
Medium	Seawater, freshwater, fuel oil, air	LNG, LPG, liquid nitrogen
Temperature	≥ -29°C	≤ -29°C
Typical Use	General ship piping systems	LNG carriers, LPG carriers, Low temperature storage

Low temperature valves are specifically engineered for ultra-low temperature service, with materials, design, and testing tailored to prevent cold brittleness and leakage. normal temperature valves are not suitable for Low temperature applications.

Installation Position and Function of Marine Butterfly Valves on Ships

July 11, 2025

A marine butterfly valve is a common type of ship valve, widely used in various piping systems onboard. Below are its installation positions and functions on a ship:

Installation Positions of Marine Butterfly Valves

Butterfly valves are mainly used in locations where the pipe diameter is large, quick opening/closing is required, and installation space is limited. They are commonly found in the following piping systems:

Ballast Water System
Installed on ballast water pipelines to control the intake, discharge, and distribution of ballast water between tanks.
For example, on ballast water mains, branch lines, and at tank inlets/outlets.

Bilge (Seawater/Wastewater) System
Installed in bilge suction and discharge systems to control the drainage of seawater or wastewater.

Cooling Water System
Installed in the seawater cooling circuits of the main engine and generators to open/close or regulate the flow of cooling water.

Firefighting System
Installed on the main and branch fire mains to enable quick opening and closing of firefighting water supply.

Ventilation/Compressed Air Pipelines
Some butterfly valves are also used in non-liquid media pipelines, such as compressed air or low-pressure gas.

In general, butterfly valves are installed horizontally or vertically on pipelines, close to the area requiring control, for easy operation.

Functions of Marine Butterfly Valves

The primary functions are shut-off and throttling. Key characteristics include compact structure, light weight, easy operation, and low fluid resistance. Specific functions are as follows:

Shut-off or Open the Flow
Quickly cut off or open the water (or gas) flow in the pipeline.

Regulate Flow
Capable of adjusting the flow to some extent, not limited to fully open or fully closed positions.

Prevent Backflow
In combination with pipeline design, it helps prevent backflow (note: the butterfly valve itself does not have a check function; a check valve is required for that purpose).

Save Space and Weight
Compared to gate valves and ball valves, butterfly valves are lighter and more suitable for the limited space onboard ships.

Why are butterfly valves preferred on ships?

More economical and practical than gate or ball valves on large-diameter pipelines.

Lightweight, low operating torque, and quick to open/close.

Resistant to seawater, freshwater, oil, and other corrosive media (commonly made of stainless steel, bronze, or with rubber sealing materials).

Marine butterfly valves are typically installed on the main and branch lines of various shipboard water systems to control and regulate the flow of liquids or gases. Due to their light weight, simple structure, and easy operation, they are widely used in marine engineering and are an indispensable valve type in modern ship piping systems.

LRS Certificates in Marine Butterfly Valve

July 1, 2025

LRS Certificates in the context of marine butterfly valves refer to certifications issued by Lloyd’s Register of Shipping (LRS), a well-known maritime classification society. These certificates verify that the valves meet the standards required for marine applications, particularly for safety, reliability, and regulatory compliance.

What Is an LRS Certificate?

An LRS Certificate demonstrates that a product—like a butterfly valve—has been:

Inspected and tested by Lloyd’s Register or an authorized party.

Compliant with Lloyd’s marine classification rules.

Suitable for use on ships and offshore platforms.

What It Means for Marine Butterfly Valves

A butterfly valve with an LRS certificate has typically passed tests related to:

Criteria	Typical Requirements
Pressure rating	Confirmed for marine system pressures
Material quality	Approved corrosion-resistant materials
Fire safety	Fire-safe design (if required)
Functionality	Reliable operation under marine conditions
Leakage tests	Zero or acceptable leakage rates

Types of LRS Certificates

There are different types depending on what’s being certified:

Certificate Type	Description
Type Approval Certificate	Confirms a valve design meets LR rules. Valid for multiple units of the same design.
Inspection Certificate (3.2)	Confirms that each valve is individually tested and inspected (often project-specific).
Works Certificate	Provided by the manufacturer, verified by LR or its representative.

Why Is It Important?

Regulatory Compliance: Required for equipment used on LR-classed vessels.

Insurance and Safety: Helps in securing vessel insurance and ensuring safe operations.

Global Acceptance: LRS is recognized by maritime authorities worldwide.

How to Verify an LRS Certificate

Check the certificate number on the LRS website.

Request the Type Approval Certificate from the valve supplier.

Ensure the stamp or signature of Lloyd’s Register is present on the physical certificate.