Magpie Sealing Technology Sharing

Typical Sealing Applications: Common Sealing Forms in Industrial Valves

Following our previous discussion on ball valve seat sealing, this issue explores the unique characteristics of butterfly valve seat sealing and other common industrial valve sealing forms.

Valve Seat Sealing

The triple-eccentric butterfly valve is widely used in modern industrial applications due to its advanced design and reliable performance.

This valve employs a radial sealing method, where the sealing occurs along the disc’s diameter. It delivers excellent sealing performance and low leakage, maintaining stable operation under high pressure, high temperature, and corrosive conditions. Achieving optimal performance requires precise machining of both the sealing surface and the sealing angle.

Nozzle Flange Sealing

The final stage of valve sealing often involves the nozzle flange, which typically employs three sealing methods: face sealing, line sealing, and quick sealing. These are crucial for ensuring tight sealing at the valve’s nozzle connection.

1. Face Sealing
   Face sealing occurs at the contact surface between the gasket and valve flange. It provides strong sealing performance, effectively preventing medium leakage.

• Gasket materials: flexible graphite, rubber, PTFE

• Applications: widely used in valves, pipelines, and equipment connections

2. Line Sealing
   Also known as linear sealing, line sealing involves linear contact between the seal and flange. It offers high reliability and stable performance under harsh conditions such as high temperature and high pressure.

• Common components: metal sealing rings, spring-energized sealing rings

• Increasingly preferred in modern valve designs

3. Quick Sealing
   Quick sealing allows fast assembly and disassembly, ideal for applications where seals are frequently replaced.

• Mechanisms: threads, snap-fit, or quick-connect structures

• Applications: valves, pipelines, and pressure-containing equipment

Body-Bonnet Flange Sealing

1. Standard Body-Bonnet Flange Sealing
   This method relies on pre-tightened bolts to compress sealing surfaces, ensuring tight sealing. It is especially critical in high-pressure valves, where internal medium pressure enhances sealing stress.

2. Flat Face Body-Bonnet Flange Sealing
   Typically using an MF flange form, the valve body has a female face flange (FM) and the bonnet has a male face flange (M).

• FM accommodates the gasket; M provides compressive force

• Common gaskets: spiral wound, corrugated metal, pure graphite, reinforced graphite

• Selection depends on operating conditions, medium, pressure, and temperature

3. Line Sealing for Body-Bonnet Flanges
   Flanges may also use line sealing structures, such as C-ring or O-ring seals, offering:

• Improved sealing tightness

• Reduced radial dimensions

• Lighter, more compact valve design

4. Self-Tightening Body-Bonnet Flange Sealing
   Self-tightening seals, similar to traditional Wood-type rings, now often use trapezoidal-section graphite.

• Initial bolt preload plus medium pressure increases sealing stress

• Highly effective for high-pressure valve applications

Low-Emission Sealing Solutions from Magpie

Magpie Sealing continues to provide innovative, low-leakage solutions for industrial valves. For questions or consultations, follow us, leave comments, or reach out directly.

In our next issue, we will explore different sealing gasket forms and their applications. Stay tuned!

It's important to know about Google SEO to help your website rank higher in search results.