Product Overview
The THINKTANK TT-A40Y Series is a direct spring-loaded, full-lift safety valve incorporating an enclosed radiator structure for high-temperature overpressure protection applications.
The series is available in pressure ratings from PN16 to PN100, with sizes up to DN200 for PN16 / PN25 / PN40 configurations and up to DN150 for PN64 / PN100 configurations.
The TT-A40Y-C configuration is suitable for service temperatures up to 400°C.
The TT-A40Y-I configuration extends the maximum operating temperature to 450°C and is specified for air, petroleum gas, hydrogen-nitrogen mixed gases and similar compatible gas services.
All TT-A40Y safety valves are intended for installation on equipment or piping systems requiring automatic overpressure protection.
Model Selection
TT-A40Y-C
The TT-A40Y-C is designed for high-temperature safety valve applications with:
Maximum operating temperature: ≤400°C
The provided product data does not specify the applicable medium for the C configuration. Medium and material compatibility should therefore be confirmed according to the actual project conditions.
TT-A40Y-I
The TT-A40Y-I is suitable for equipment and pipelines handling:
- Air
- Petroleum gas
- Hydrogen-nitrogen mixed gases
- Similar compatible media
Maximum operating temperature: ≤450°C
Actual material compatibility should be verified according to the process composition, operating pressure and temperature.
Quick Specifications
| Parameter | Specification |
|---|---|
| Model | TT-A40Y-C / TT-A40Y-I |
| Product Type | High-Temperature Spring-Loaded Safety Valve |
| Connection | Flanged |
| Size Range | DN20–DN200 depending on pressure rating |
| Pressure Rating | PN16 / PN25 / PN40 / PN64 / PN100 |
| Design | Direct Spring-Loaded |
| Lift Type | Full Lift |
| Bonnet Structure | Enclosed Radiator Type |
| TT-A40Y-C Temperature | ≤400°C |
| TT-A40Y-I Media | Air, petroleum gas, hydrogen-nitrogen mixed gases |
| TT-A40Y-I Temperature | ≤450°C |
| Function | Automatic Overpressure Protection |
| Manufacturer | THINKTANK |
How It Works
The TT-A40Y operates as a direct spring-loaded safety valve.
During normal operation, spring force keeps the valve disc seated and maintains the valve in the closed position.
When pressure in the protected equipment or piping system reaches the specified set pressure, the pressure force acting on the disc overcomes the spring force and causes the valve to open.
The process medium is discharged through the valve outlet, reducing pressure within the protected system.
As system pressure decreases to the reseating range, spring force moves the disc back toward the seat and the valve recloses automatically.
High-Temperature Radiator Design
The TT-A40Y incorporates an enclosed radiator section between the valve body and spring housing, distinguishing it from conventional enclosed safety valve configurations.
This extended structure is designed for elevated-temperature service and increases the separation between the hot process section and the spring assembly.
The TT-A40Y-C is rated for operating temperatures up to 400°C, while the TT-A40Y-I configuration extends the listed maximum operating temperature to 450°C.
For high-temperature applications, final selection should consider not only the process temperature but also the valve material configuration, set pressure, relieving temperature and installation environment.
Full-Lift Design
The TT-A40Y uses a full-lift configuration.
Under the general performance criteria applicable to this safety valve family:
Lift H ≥ 1/4 d₀
where:
- H = Valve lift
- d₀ = Orifice diameter
The full-lift configuration provides a larger available discharge area than a low-lift design and is suitable for applications requiring greater relieving capacity.
The actual valve size must still be selected according to the required relieving load and process conditions rather than nominal flange size alone.
Typical Applications
The TT-A40Y Series can be considered for:
- High-temperature process piping
- High-temperature gas systems
- Petroleum gas systems
- Air systems
- Hydrogen-nitrogen mixed-gas systems
- Pressure vessels
- Thermal process equipment
- Packaged high-temperature process systems
- Skid-mounted equipment
- Industrial equipment requiring high-temperature overpressure protection
Final valve selection should consider the actual medium, set pressure, operating and relieving temperature, required relieving capacity, back pressure, pressure rating and material compatibility.
General Performance Requirements
| Applicable Medium | Shell Test Pressure Ps | Seal Test Pressure Pm | Blowdown ΔP | Discharge Pressure Pp | Lift Height H |
| Steam | — | 90% Pk or the minimum reseating pressure, whichever is lower | When Pk ≤ 0.4 MPa: ΔP ≤ 0.04 MPa; when Pk > 0.4 MPa: ΔP ≤ 10% Pk | ≤ 1.03 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
| Air or other gases | 1.5 PN | When Pk ≤ 0.3 MPa: Pm = Pk − 0.03 MPa; when Pk > 0.3 MPa: Pm = 90% Pk | When Pk ≤ 0.2 MPa: ΔP ≤ 0.03 MPa; when Pk > 0.2 MPa: ΔP ≤ 15% Pk | ≤ 1.1 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
| Water or other liquids | — | When Pk ≤ 0.3 MPa: Pm = Pk − 0.06 MPa; when Pk > 0.3 MPa: Pm = 80% Pk | When Pk ≤ 0.3 MPa: ΔP ≤ 0.06 MPa; when Pk > 0.3 MPa: ΔP ≤ 20% Pk | ≤ 1.2 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
Notes:
- Pk = Set pressure
- d₀ = Orifice diameter
- PN = Nominal pressure
- Actual test and performance requirements shall be confirmed according to the selected valve model, project specification and applicable standard.
For the TT-A40Y Series, the full-lift criterion applies: H ≥ 1/4 d₀.
For TT-A40Y-I gas applications, the air or other gases performance requirements are the primary applicable reference.
Dimensions – PN16 / PN25 / PN40
| DN | Orifice d₀ (mm) | Outlet DN′ | L (mm) | L₁ (mm) | H Approx. (mm) |
| 20 | 15 | 25 | 110 | 95 | 360 |
| 25 | 16 | 32 | 110 | 95 | 360 |
| 32 | 20 | 40 | 115 | 100 | 365 |
| 40 | 25 | 50 | 120 | 110 | 380 |
| 50 | 32 | 65 | 135 | 120 | 400 |
| 65 | 40 | 80 | 160 | 140 | 500 |
| 80 | 50 | 100 | 170 | 135 | 512 |
| 100 | 65 | 125 | 205 | 160 | 635 |
| 125 | 80 | 150 | 210 | 190 | 710 |
| 150 | 100 | 175 | 255 | 230 | 725 |
| 200 | 125 | 250 | 305 | 260 | 880 |
Dimensions – PN64 / PN100
| DN | Orifice d₀ (mm) | Outlet DN′ | L (mm) | L₁ (mm) | H Approx. (mm) |
| 20 | 12 | 25 | 110 | 100 | 355 |
| 25 | 16 | 32 | 110 | 100 | 355 |
| 32 | 20 | 40 | 130 | 110 | 375 |
| 40 | 25 | 50 | 135 | 120 | 390 |
| 50 | 32 | 65 | 160 | 130 | 495 |
| 65 | 40 | 80 | 175 | 160 | 605 |
| 80 | 50 | 100 | 175 | 160 | 615 |
| 100 | 65 | 125 | 195 | 195 | 695 |
| 150 | 100 | 200 | 285 | 260 | 995 |
Dimensions are for preliminary engineering and layout reference. Final approved dimensional drawings should be confirmed before piping fabrication or installation.
Pressure Rating and Size Range
Available valve sizes depend on the nominal pressure class.
PN16 / PN25 / PN40: DN20–DN200
PN64 / PN100: DN20–DN150
Nominal pressure rating and flange size alone do not determine the required safety valve. Set pressure, relieving conditions, temperature and required discharge capacity must also be verified.
Safety Valve Sizing and Selection
For correct selection of the TT-A40Y high-temperature safety valve, provide:
- Required model: TT-A40Y-C or TT-A40Y-I
- Process medium and composition
- Set pressure
- Operating pressure
- Design pressure
- Operating temperature
- Relieving temperature
- Required relieving capacity
- Back pressure
- Inlet DN
- Outlet DN
- Pressure rating
- Required body and trim materials
- Applicable standards or certification requirements
- Installation and discharge arrangement
For hydrogen-nitrogen mixed gas and other gas services, gas composition and relevant thermodynamic properties should be included in the relieving capacity evaluation.
For high-temperature service, material selection and the actual relieving temperature should be reviewed together with the pressure conditions.
Engineering Support
THINKTANK supports EPC contractors, system integrators, pressure equipment manufacturers, high-temperature process equipment manufacturers and industrial users with:
- High-temperature safety valve sizing and selection
- Relieving capacity calculation and review
- Set-pressure configuration
- Temperature and material compatibility review
- Pressure class selection
- Dimensional drawings
- 3D models for system integration
- Existing safety valve replacement evaluation
- Project-specific technical documentation
With more than 30 years of industrial valve application experience, THINKTANK can support high-temperature safety valve selection, equivalent replacement and project-specific application review.
