What are Rubber Liner Butterfly Valves?
A rubber-lined valve is a type of valve where the elastomer is adhered to the body of the metal. This is through a high-temperature vulcanization process. Unlike a regular rubber seat butterfly valve, this valve type has a lining that extends throughout its internal flow path. This design then creates a permanent barrier between the medium and the valve body.
Consequently, the butterfly valve rubber lining is held permanently in position by the high-velocity flow of the medium. This helps the valve provide superior corrosion resistance properties for abrasives and aggressive media. It ensures that the fluid can only touch the elastomer and valve disc. As a result, engineers can use cheaper materials like ductile iron for the valve.
How do Rubber-Lined and Rubber-Seated Valves Differ?
Rubber-lined and rubber-seated valves differ in construction and performance. Knowing the distinction in structure forms the basis of the purchasing process.
Consumers have been known to mistake rubber seat butterfly valves for rubber liner butterfly valves since both are butterfly-type valves. With that, below is a comparison table that highlights their differences:
| Feature | Rubber-Seated Butterfly Valve | Rubber-Lined Butterfly Valve |
| Construction | Replaceable rubber ring fitted in the body. | Rubber is vulcanized and adhered to the body. |
| Corrosion Protection | Protects the sealing area only. | Seals the whole body completely. |
| Sealing Method | Interference fit between disc and seat. | Permanent, non-movable sealing surface. |
| Typical Media | Clean water, air, and non-corrosive liquids. | Acids, alkalis, slurries, and sea water. |
| Maintenance | Seats can be replaced easily in the field. | The liner is permanent or cannot be replaced easily. |
| Primary Application | General-purpose HVAC and irrigation applications. | Chemical processing, mining, and power stations. |
What are the Common Lining Materials?
The common lining materials vary based on the required chemical resistance. EPDM-lined butterfly valves have been used extensively in many industries, although there are some limitations to their use. For more details, see our article comparing the characteristics of NBR vs EPDM valve seats. Here is a table listing some common elastomers for rubber-lined valves.
| Material | Temp Range (°C) | Common Compatible Media |
| EPDM | -20 to +120 | Hot water, dilute acids, alkaline solutions. |
| NBR | -10 to +80 | Oils, fats, fuels, and hydrocarbons. |
| Natural Rubber (NR) | -30 to +80 | Abrasive slurries, mining waste, sand. |
| Neoprene (CR) | -20 to +90 | Sea water, refrigerants, mild weathering. |
| Viton (FKM) | -20 to +200 | High-heat chemicals, strong acids. |
Where are Rubber-Lined Butterfly Valves Used?
Rubber-lined butterfly valves are used in applications requiring extreme conditions that involve corrosion, wear, and exposure to chemicals:
Water Treatment Processes
- Can be utilized to convey potable water and untreated sewage. Its vulcanized layer provides protection against corrosion of the iron valve due to moisture.
Wastewater Systems
- The rubber liner is non-reactive with the grease and oil contained in the water stream.
Power Plants – Flue Gas Desulfurization (FGD)
- The rubber coating is thick enough to withstand the abrasive properties of lime slurry.
Mining Industries
- Rubber lining bonded to the valve prevents tearing caused by the solid particles in the slurry.
Chemical Manufacturing Industries
- EPDM liners ensure reliability in dealing with acids, and corrosive fluids do not interact directly with metal valves. This prevents catastrophic structural failure of the pipeline.
Desalinization Facilities
- Either neoprene or EPDM lining can be applied when exposed to high-salinity seawater.
How Do You Select the Right Valve?
To select the right valve, follow a systematic evaluation of technical requirements:
- Chemical composition of the medium should be identified, considering the acid/oil concentration level.
- Determine the highest and lowest temperatures for operation. This is because the elastomer may become hard when it is cold, while becoming soft when it is hot.
- Pressure rating must be determined (such as PN10, PN16, or Class 150).
- You must choose whether the body must be either fully lined or partly lined, depending on the level of corrosion present.
- The type of connection must be determined (such as wafer, lug, or double flanged).
What are the Technical Standards for these Valves?
The technical standards for these valves ensure consistent performance and safety in operation.
Specifications like EN 593 and API 609 regulate dimensioning and testing procedures. WRAS certification is mandatory for valves used in drinking water systems. Fire safety standards include API 607 fire-test certification for valves. These standards guarantee that the valve functions at predetermined pressure and temperature levels.
Moreover, manufacturing requires stringent testing for the vulcanization seal. Pull tests ascertain that the rubber does not detach under vacuum operations. Whereas, pressure testing in accordance with ISO 5208 standards guarantees bubble-free shut-off.
What Are Some Real-Life Case Studies?
Petrochemical Refinery Slop Oil and Hydrocarbon Separation (Texas, USA)
A petrochemical refining complex along the Texas Gulf Coast experienced chronic valve binding and elastomer swelling within wastewater slop oil separation systems. Maintenance teams originally installed EPDM-lined butterfly valves, but petroleum hydrocarbons and aromatic solvents caused severe rubber swelling and material degradation problems.
The absorbed oil particles caused the EPDM liners to blister, expand, and tear repeatedly during normal valve closure and isolation operations. To resolve these failures, engineers redesigned the system using NBR rubber-lined butterfly valves specifically developed for oil-resistant industrial service applications.
Because NBR contains high acrylonitrile content, the material resists fuels, oils, and non-polar solvents without losing structural elasticity or sealing integrity. The upgraded valves maintained reliable zero-leakage isolation between minus twenty and plus one-hundred-twenty degrees Celsius during continuous refinery operations.
Model NO.: D342X, D3L2X, D372X
Nominal Diameter: DN50–DN3600
Conclusion
The proper elastomer guarantees that the rubber liner butterfly valves have a permanent protective barrier against body erosion and leakage in high-velocity systems. Compliance with EN 593 and API 609 ensures valves meet pressure and dimensional standards. Meanwhile, ISO 5208 and WRAS certifications verify leakage performance and material compliance.
CTGV is a professional butterfly valve manufacturer with extensive manufacturing capabilities in high-temperature vulcanization. Our factory utilizes specialized equipment to bond butterfly valve rubber directly to the metal body for maximum durability. Additionally, we deliver custom-lined solutions for the mining, chemical, and water sectors.
Contact us today to find the best CTGV rubber-lined butterfly valve for your project.
