Product Overview
The THINKTANK TT-A48SH Series is a spring-loaded, full-lift safety valve designed for high-temperature and high-pressure overpressure protection of industrial equipment and piping systems.
Different TT-A48SH configurations are available for progressively higher operating temperatures, with listed maximum service temperatures ranging from 425°C to 550°C.
The series is available in pressure ratings from PN16 to PN100, with nominal sizes up to DN250 depending on the selected pressure class and configuration.
The TT-A48SH-V configuration is specifically identified for steam and similar media at operating temperatures up to 550°C.
Model Selection
TT-A48SH-C
The TT-A48SH-C is suitable for high-temperature service with:
Maximum operating temperature: ≤425°C
The supplied product data does not specify the applicable medium for this configuration. Medium and material compatibility should therefore be confirmed according to the actual process conditions.
TT-A48SH-I
The TT-A48SH-I is designed for higher-temperature service with:
Maximum operating temperature: ≤510°C
The supplied product data does not specify the applicable medium for this configuration. Final selection should therefore consider the actual medium, pressure and temperature.
TT-A48SH-V
The TT-A48SH-V is suitable for:
- Steam
- Similar compatible media
Maximum operating temperature: ≤550°C
This configuration is the highest-temperature version listed for the TT-A48SH Series.
Quick Specifications
| Parameter | Specification |
|---|---|
| Model | TT-A48SH-C / TT-A48SH-I / TT-A48SH-V |
| Product Type | High-Temperature & High-Pressure Safety Valve |
| Design | Direct Spring-Loaded |
| Lift Type | Full Lift |
| Connection | Flanged |
| Size Range | DN25–DN250 depending on pressure rating |
| Pressure Rating | PN16 / PN25 / PN40 / PN64 / PN100 |
| TT-A48SH-C Temperature | ≤425°C |
| TT-A48SH-I Temperature | ≤510°C |
| TT-A48SH-V Medium | Steam and similar media |
| TT-A48SH-V Temperature | ≤550°C |
| Function | Automatic Overpressure Protection |
| Manufacturer | THINKTANK |
How It Works
The TT-A48SH operates as a direct spring-loaded full-lift safety valve.
During normal operation, spring force keeps the valve disc seated and the valve closed.
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 then discharged through the valve outlet, reducing pressure within the protected system.
As pressure decreases into the reseating range, spring force returns the disc toward the seat and the valve recloses automatically.
High-Temperature Design
The TT-A48SH Series is intended for applications where conventional-temperature safety valve configurations may not be suitable.
The three listed temperature configurations provide different maximum operating temperature levels:
- TT-A48SH-C: ≤425°C
- TT-A48SH-I: ≤510°C
- TT-A48SH-V: ≤550°C
For applications approaching these temperatures, final valve selection should consider not only the process operating temperature but also the relieving temperature, body and trim materials, spring temperature exposure, sealing arrangement and applicable project requirements.
The actual material configuration should be confirmed according to the selected temperature class and process medium.
Full-Lift Design
The TT-A48SH 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 construction provides a larger available discharge area than a low-lift design and is therefore suitable for applications requiring greater relieving capacity.
Actual valve capacity must still be verified against the required relief load and actual relieving conditions.
Typical Applications
The TT-A48SH Series can be considered for:
- High-temperature steam systems
- High-temperature process piping
- Power and thermal process equipment
- Pressure vessels
- High-temperature industrial gas systems
- High-pressure process equipment
- Boiler and steam-related systems
- Packaged process units
- Skid-mounted high-temperature equipment
- Industrial systems requiring overpressure protection at elevated temperatures
Final valve selection should consider the actual medium, set pressure, operating pressure, relieving temperature, required relieving capacity, back pressure 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 configuration, project specification and applicable standard.
For the TT-A48SH Series, the full-lift criterion applies: H ≥ 1/4 d₀.
For TT-A48SH-V steam applications, the steam-service performance requirements are the primary applicable reference.
Dimensions – PN16 / PN25 / PN40
| DN | Orifice d₀ (mm) | Outlet DN′ | L (mm) | L₁ (mm) | H Approx. (mm) |
| 25 | 15 | 32 | 110 | 95 | 395 |
| 40 | 25 | 50 | 120 | 110 | 418 |
| 50 | 32 | 65 | 135 | 120 | 525 |
| 50 | 32 | 80 | 135 | 120 | 525 |
| 80 | 50 | 100 | 170 | 135 | 675 |
| 100 | 65 | 125 | 205 | 160 | 748 |
| 100 | 65 | 150 | 205 | 160 | 748 |
| 150 | 100 | 200 | 230 | 210 | 1135 |
| 200 | 125 | 250 | 290 | 310 | 1230 |
| 250 | 150 | 300 | 350 | 320 | 1285 |
Dimensions – PN64 / PN100
| DN | Orifice d₀ (mm) | Outlet DN′ | L (mm) | L₁ (mm) | H Approx. (mm) |
| 40 | 25 | 50 | 135 | 120 | 518 |
| 50 | 32 | 65 | 160 | 130 | 625 |
| 50 | 32 | 80 | 160 | 145 | 600 |
| 80 | 50 | 100 | 175 | 160 | 740 |
| 100 | 65 | 125 | 220 | 200 | 920 |
| 100 | 65 | 150 | 220 | 200 | 920 |
| 150 | 90 | 200 | 280 | 280 | 1128 |
| 200 | 125 | 250 | 300 | 295 | 1350 |
| 250 | 150 | 350 | 370 | 390 | 1440 |
Dimensions are for preliminary engineering and layout reference. Final approved dimensional drawings should be confirmed before piping fabrication or installation.
Some nominal inlet sizes are listed with more than one outlet DN′ configuration. The required inlet/outlet combination should therefore be confirmed during final valve selection.
Pressure Rating and Size Range
PN16 / PN25 / PN40: listed sizes DN25–DN250
PN64 / PN100: listed sizes DN40–DN250
The nominal pressure class and connection size alone do not determine the correct safety valve configuration.
For high-temperature service, set pressure, relieving temperature, required capacity and valve material configuration must be reviewed together.
Safety Valve Sizing and Selection
For correct selection of the TT-A48SH Series, provide:
- Required model: TT-A48SH-C, TT-A48SH-I or TT-A48SH-V
- Process medium
- Medium 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 and certification requirements
- Installation and discharge arrangement
For steam service up to 550°C, relieving temperature, steam conditions and material requirements are particularly important and should be confirmed before final valve selection.
Engineering Support
THINKTANK supports EPC contractors, power and energy companies, process equipment manufacturers, system integrators and industrial users with:
- High-temperature safety valve sizing and selection
- High-pressure safety valve application review
- Relieving capacity calculation
- Set-pressure configuration
- High-temperature material selection
- 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 safety valve selection and equivalent replacement for demanding high-temperature and high-pressure applications.
