Blind Flange Valve

About this part

Blind flange valve, commonly known as a "spectacle valve" in the industry, is a safety gate valve specifically designed for the absolute shut-off of gaseous media. Its design and manufacturing strictly adhere to the requirements of GB6222 Industrial Enterprise Gas Safety Regulations, with the core mission of providing reliable safety protection for various gas pipeline systems. This valve is widely used in gas pipelines in industrial and mining enterprises, municipal facilities, and environmental protection fields, and is particularly suitable for shutting off toxic, harmful, flammable, and explosive gases, ensuring safety during maintenance operations. It can also be used as a blind flange at the end of a pipeline, significantly shortening system maintenance and isolation time.

Structure and Composition

The blind flange valve has a scientifically designed, rigid structure, mainly composed of the following parts:

Valve body structure: Consists of a left valve body, a right valve body, a middle valve body, and connecting bolts, forming a robust rigid frame to ensure the valve's stability under pressure.

Core components: The core component is a sector-shaped valve plate (gate), whose function is similar to the lenses of "spectacles": one side is a blind plate, and the other side is a through-hole plate. By rotating this valve plate, the pipeline can be switched between "open" and "closed" states.

Driving system: Usually equipped with three sets of driving devices with clearly defined functions:

Clamping/releasing device: Mostly manual (some models can be electric, pneumatic, or hydraulic), responsible for pressing or releasing the sealing pair before and after operation.

Valve plate switching device: Often uses an electric actuator (pneumatic or hydraulic can also be selected depending on working conditions), responsible for driving the sector-shaped valve plate to switch between the blind plate position and the through-hole position.

Sealing system: Uses high-performance rubber sealing rings, installed on the left and right valve bodies respectively, forming a reliable bidirectional sealing structure to ensure zero leakage when the valve is closed.

Working Principle and Features

The opening and closing operation of the blind plate valve follows a rigorous two-step process of "loosen first, then rotate; rotate first, then tighten" to ensure that the sealing surface is not damaged and complete shut-off is achieved:

Loosening stage: First, activate the two clamping devices to separate the left and right valve bodies from the sealing ring, creating space for the valve plate to rotate.

Switching stage: Then, activate the valve plate switching device (such as an electric push rod) to drive the sector-shaped valve plate to rotate 180°, switching the pipeline from the "open passage" state to the "blind plate shut-off" state, or vice versa.

Clamping stage: After the valve plate is in place, operate the clamping device again to press the left and right valve bodies against the sealing ring, forming a forced seal.

Special attention: To ensure equipment safety and service life, it is strictly prohibited to forcibly activate the valve plate switching device when the clamping device is not completely loosened.

Its main performance characteristics are as follows:

Absolute shut-off: Physical isolation is achieved through a solid blind plate, ensuring absolute shut-off of gaseous media, which is safe and reliable.

Excellent sealing: Double sealing ring design, good sealing performance, and the maximum sealing test pressure can reach 0.275MPa.

Diverse drive options: Provides multiple driving methods such as manual, electric, pneumatic, and hydraulic, and can achieve remote automated control.

Safe operation: Logically interlocked operation process effectively prevents misoperation and ensures personal and equipment safety.

Compact structure: Small size, light weight, and fast opening and closing action, easy to install and operate.

Strong adaptability: Wide nominal pressure range (0.05-0.25MPa), and depending on the sealing material, the applicable temperature can reach up to 300℃. The main material of the valve body is carbon steel, and the connecting flange conforms to JB/T81-94 and other standards, ensuring good versatility.

Main Types

According to the specific structural form and driving method, blind plate valves can be mainly divided into: electric blind plate valves, hydraulic blind plate valves, enclosed Slide gate valves, and electric open-type blind plate valves, etc. Users can choose according to actual working conditions.

Performance Parameters

Connection Dimensions

• Outline Drawing

• Connection Dimensions Table

Quality documentation included

• Dimensional inspection report (CMM / profile projector) for critical features
• Material certificate with heat number traceability
• Surface finish and hardness records where specified
• Photographic packing record before shipment

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