Blind Plate

Product Overview of CPVC Blind Flange

CPVC Blind Flange, also known as flange cover​ or pipe plug, is a high-performance piping component engineered from unplasticized polyvinyl chloride (CPVC) specifically designed for isolating, sealing, and terminating pipelines in industrial systems . This solid, disc-shaped flange without a center hole serves as a reliable, removable sealing solution across various applications including chemical processing, water treatment, industrial plumbing, and corrosive fluid handling systems . Unlike permanent seals like heads or caps, the CPVC blind flange offers the distinct advantage of being easily installed and removed as needed, providing flexible isolation capabilities while maintaining exceptional corrosion resistance and durability .

Manufactured to meet international standards including both national (GB) and American (ANSI) specifications, CPVC blind flanges are available in a comprehensive size range from DN15 to DN600 (1/2″ to 10″) to accommodate diverse piping requirements . With pressure ratings typically spanning 1.0MPa (10kg) to 1.6MPa (16kg), these components are engineered to deliver long-term performance in demanding environments while being significantly lighter than equivalent metal flanges .

Key Features of CPVC Blind Flange

Exceptional Corrosion Resistance

CPVC blind flanges demonstrate superior resistance​ to acids, alkalis, and chemical corrosion, making them ideal for chemical processing, wastewater treatment, and industrial applications involving aggressive media . The non-metallic composition eliminates galvanic corrosion concerns and ensures long-term integrity even when handling corrosive substances that would rapidly degrade metal flanges .

Lightweight Construction with Robust Mechanical Strength

Weighing approximately one-fifth of equivalent steel flanges, CPVC blind flanges significantly reduce installation effort and transportation costs while maintaining impressive mechanical strength . Despite their lightweight nature, these flanges offer substantial pressure endurance​ with working pressures typically rated at 1.6MPa, suitable for most industrial applications .

Reliable Sealing Performance

Featuring multiple sealing surface options​ including plane, convex, concave and convex surfaces, tongue and groove surfaces, and ring connection surfaces, CPVC blind flanges ensure leak-proof isolation . The bolted connection system provides a secure yet removable seal​ that can be repeatedly engaged and disengaged as operational requirements change .

Thermal and Electrical Properties

CPVC blind flanges maintain performance across a temperature range of 0°C to 75°C, with some formulations extending to 90°C for specific materials like CPVC . Additionally, CPVC’s natural electrical insulation properties​ prevent galvanic corrosion and make these flanges suitable for electrical isolation applications .

Smooth Surface and Hygienic Properties

The non-porous, smooth surface​ of CPVC blind flanges prevents scaling, accumulation of deposits, and bacterial growth, ensuring maintained hygiene and flow characteristics over time . This makes them suitable for potable water applications​ and industries with strict sanitary requirements such as food processing and pharmaceutical manufacturing .

Applications of CPVC Blind Flange

Isolation for Maintenance and Safety

CPVC blind flanges provide reliable isolation​ during equipment maintenance, inspection, or system modifications, ensuring complete separation of pipeline sections . They serve as a critical safety measure​ by positively isolating sections of pipeline where accidental flow could create hazardous conditions during maintenance activities .

Chemical and Industrial Processing

In chemical plants, manufacturing facilities, and industrial complexes, CPVC blind flanges offer corrosion-resistant isolation​ for aggressive chemical media including acids, alkalis, and solvents . Their compatibility with diverse chemical environments makes them suitable for pharmaceutical production, electroplating operations, semiconductor manufacturing, and petrochemical processing .

Water and Wastewater Treatment

CPVC blind flanges are extensively used in water treatment plants, desalination facilities, and sewage systems where corrosion resistance and long service life are essential . Applications include isolation of filtration systems, chemical dosing lines, and reactor tanks in both municipal and industrial water treatment facilities .

Multi-System Pipeline Configurations

In complex industrial plants with multiple parallel systems, CPVC blind flanges enable isolation of individual production trains while maintaining operation in adjacent lines . This allows for staged commissioning​ of new facilities and efficient maintenance​ scheduling without complete plant shutdowns .

Specialized Configurations: Figure-8 Blind Flanges

The distinctive figure-8 blind flange​ (spectacle blind) provides visual indication of isolation status with a blind plate on one end and a throttle ring on the other . This design allows quick changeover between operational and isolation states while providing clear visual confirmation​ of the system status .

Technical Specifications

Table: Standard CPVC Blind Flange Specifications

Parameter​	Specification​	Standards​
Size Range​	DN15 to DN600 (1/2″ to 10″)	International standards
Pressure Rating​	1.0MPa (10kg) to 1.6MPa (16kg)	Standard industrial pressure classes
Temperature Range​	0°C to 75°C (CPVC); up to 90°C for CPVC/PP variants	Material-dependent specifications
Material​	CPVC, with options for CPVC, PPH, PVDF, and reinforced plastics	Industry-standard materials
Connection Type​	Flange connection (bolt-fastened)	Standard flange practice
Manufacturing Standard​	National (GB), American (ANSI), and other international standards	Compliance with multiple standards

SIZE	Number	D1	D2	L1	r-φe
DN15	MBL15	95	65	12	4-φ18
DN20	MBL20	105	75	13.4	4-φ18
DN25	MBL25	115	85	15	4-φ18
DN32	MBL32	140	100	16	4-φ18
DN40	MBL40	150	110	17.5	4-φ18
DN50	MBL50	165	125	19	4-φ18
DN65	MBL65	185	145	22.3	4-φ18
DN80	MBL80	200	160	22.8	8-φ18
DN100	MBL100	220	180	25	8-φ18
DN125	MBL125	250	210	32	8-φ18
DN150	MBL150	285	240	33	8-φ22
DN200	MBL200	340	295	34	8-φ22

Frequently Asked Questions (FAQs)

Q1: What are the key advantages of CPVC blind flanges compared to metal alternatives?

CPVC blind flanges offer superior corrosion resistance, significantly lighter weight​ (approximately 1/5 the weight of steel), cost-effectiveness, and electrical insulation properties​ that make them ideal for corrosive environments and applications where galvanic corrosion is a concern .

Q2: Can CPVC blind flanges be customized for specific application requirements?

Yes, CPVC blind flanges can be customized in terms of dimensions​ (from DN15 to DN600), pressure ratings, and specific material formulations​ to meet unique application requirements, including specialized sealing surfaces and connection configurations .

Q3: What is the typical service life of CPVC blind flanges?

CPVC blind flanges offer an exceptional service life​ exceeding 40-50 years in appropriate applications, thanks to their corrosion resistance, UV stability (when properly formulated), and maintenance-free operation .

Q4: How do CPVC blind flanges compare to other isolation methods like valves?

Unlike valves that may leak through the seat over time, CPVC blind flanges provide absolute, positive isolation​ when properly installed . They are considered the most reliable method for complete system isolation, particularly for maintenance safety or long-term system segregation .

Q5: What standards govern the manufacture of CPVC blind flanges?

CPVC blind flanges are produced according to various international standards including GB (Chinese National Standard), ANSI/ASME (American), and other region-specific standards, ensuring compatibility with global piping system requirements .