Bellow Seal Safety Valve Manufacturer in Canada

A Bellow Seal Safety Valve is designed  for applications where both leak-proof performance and overpressure protection are vital. The welded metal bellows ensures that there will be no escape of process fluids from the stem, providing accurate pressure relief in dangerous and corrosive processes.  As a topmost Bellow Seal Safety Valve Manufacturer in Canada, ValvesOnly Canada manufactures high-performance valves serving customers across Toronto, Calgary, Edmonton, Vancouver, Montreal, and throughout Canada.

Bellow Seal Safety Valve Technical Summary:

• Nominal Size: 1″ x 2″ to 8″ x 10″
• Pressure Class: Class 150 to Class 2500
• Set Pressure Range: As per ASME Section VIII requirements
• Back Pressure Capability: Up to 30-50% of set pressure
• Temperature Range: -196°C to 550°C
• Design Standards: API 520, API 526, ASME Section VIII, ASME B16.34
• Seat Tightness Standard: API 527
• Inspection and Testing: API 527, ASME Section VIII

Bellow Seal Safety Valve Construction and Materials:

Body and Pressure Retaining Parts:

• ASTM A216 WCB
• ASTM A351 CF8M
• ASTM A182 F316
• ASTM A890 F51

Internal Components:

• Disc: Stainless Steel / Stellite Faced Stainless Steel
• Nozzle: ASTM A182 F316, ASTM A182 F6a
• Stem: ASTM A182 F316
• Spring: Alloy Steel Spring
• Bellows Assembly: Multi-layer Stainless Steel Bellows

Sealing System:

• Seat: Metal Seated
• Gasket: Graphite / Spiral Wound
• Packing: Graphite

How a Bellow Seal Safety Valve Maintains Accurate Pressure Relief Performance?

The Bellow Seal Safety Valve is a spring-loaded safety valve, which incorporates an assembly of metallic bellows that separates the spring chamber from process medium as well as back pressure. The difference between this valve and normal safety valves is that the bellows balance the back pressure at the outlet, thus ensuring continuous performance regardless of the changes in the downstream environment.

The Bellow seal safety valve, therefore, can deal with back pressure buildup, superimposed back pressure, and variable back pressure applications with accuracy of performance and reliable reseating. It also ensures the protection of the spring mechanism from any corrosive process medium.

Bellow Seal Safety Valve Material Grades and Alloy Options:

Standard Materials:

Component	Material	Grade	Typical Application
Body	Carbon Steel	ASTM A216 WCB	Standard process and steam service
Body	Stainless Steel	ASTM A351 CF8M	Corrosive process service
Body	Duplex Stainless Steel	ASTM A890 F51	Offshore and chloride environments
Disc	Stainless Steel	ASTM A182 F316	Pressure relief and sealing service
Bellows	Stainless Steel	SS316L	Back pressure compensation and spring isolation
Nozzle	Stainless Steel	ASTM A182 F316	Corrosion resistance and seat integrity

Extended Materials (On Request):

• 316L Stainless Steel Bellows for corrosive media and extended fatigue life
• Inconel 625 Bellows for high-temperature and severe cyclic service
• Hastelloy C276 for aggressive chemical and oxidizing environments
• Alloy 20 (ASTM A351 CN7M) for sulfuric acid and acidic process applications

Bellow Seal Safety Valve Additional Information:

Feature	Description
Valve Type	Bellow Seal Safety Valve
Operation	Automatic Spring Loaded
Seat Design	Metal Seat
Back Pressure Capability	Up to 30-50% of Set Pressure
Bellows Function	Spring chamber isolation and back pressure balancing
Failure Detection	Bonnet vent for bellows leakage indication
Pressure Relief Type	Automatic Overpressure Protection
Installation Position	Vertical Installation Recommended

Bellow Seal Safety Valve End Connection Options:

• Flanged as per ASME B16.5
• Raised Face (RF) flanges
• Ring Type Joint (RTJ) flanges
• Customized end connections based on project requirements

Bellow Seal Safety Valve Standards and Compliance:

Our Balanced Bellows Safety Valve is designed and manufactured according to internationally recognized pressure relief standards:

• API 520 for sizing and selection
• API 526 for standardized dimensions and orifice sizes
• API 527 for seat tightness testing
• ASME Section VIII for pressure vessel overpressure protection
• ASME B16.34 for pressure-temperature ratings

Every valve undergoes hydrostatic testing, seat leakage testing, set pressure calibration, and bellows integrity verification to ensure reliable overpressure protection and accurate pressure relief performance.

Bellow Seal Safety Valve Applications:

• Petrochemical industry: pressure protection in hydrocarbon process units
• Oil and gas processing: flare header safety valve applications with varying outlet pressure
• Chemical processing: corrosive and hazardous media protection
• Power generation: steam and utility overpressure protection
• Refining facilities: shared discharge and vent header systems
• Hydrogen processing systems: leak-free pressure relief applications
• Gas handling systems: reliable protection under variable back pressure conditions
• Critical process systems: applications requiring high integrity pressure protection