🔎 Comparison Between Two Types of Globe Valves

1. Overview

✅ Globe Valve – Bolted Bonnet

• The bonnet is secured to the valve body using bolts
• This is a conventional and widely used design

✅ Globe Valve – Pressure Seal (Non-Bonnet Type)

• No traditional bolted bonnet
• Uses a pressure seal mechanism for tight sealing

⚙️ 2. Detailed Comparison

🔥 3. Key Difference

🔴 Bolted Bonnet

• Depends on:
  • Bolt tightening force
  • Gasket condition
• Under:
  • High temperature → gasket expansion
  • High pressure → potential leakage

👉 Higher risk of leakage in extreme conditions

🟢 Pressure Seal

• Higher internal pressure → tighter sealing
• Does not rely on conventional gasket sealing

👉 Ideal for:

• Class 1500 / 2500
• Superheated steam
• Power plants and oil & gas industries

🏭 4. Applications

Bolted Bonnet is suitable for:

• Medium to high pressure systems
• Applications requiring frequent maintenance
• Water, oil, and general industrial services

Pressure Seal is suitable for:

• Very high pressure (Class 1500 – 2500+)
• High temperature environments
• Critical systems such as:
  • Power plants (boilers, steam lines)
  • Refineries
  • Petrochemical plants

⚠️ 5. Technical Note

• Class 2500 valves can handle pressure up to approximately 400 bar (depending on temperature)
  👉 For such conditions, pressure seal design is often preferred

💡 6. Conclusion

• Bolted Bonnet
  → Easier maintenance, lower cost, general-purpose use
• Pressure Seal (Non-Bonnet)
  → Superior for high pressure, safer, used in critical applications