Product Overview
The THINKTANK TT-A27H/Y Series is a direct spring-loaded, low-lift threaded safety valve equipped with a lever mechanism for overpressure protection of equipment and process piping.
The series is available from DN15 to DN80 and is designed for water, air, steam, corrosive media and similar process services depending on the selected model.
Its threaded connection and compact construction make the TT-A27H/Y suitable for small and medium-size piping systems where a flanged safety valve is not required.
Model Selection
TT-A27H
The TT-A27H is suitable for equipment and pipelines handling:
- Water
- Air
- Steam
- Similar compatible media
Operating temperature: ≤200°C
TT-A27Y-P/R
The TT-A27Y-P/R is designed for equipment and pipelines handling:
- Corrosive media
Operating temperature: ≤200°C
Material compatibility should be verified according to the actual medium, concentration, temperature and operating conditions.
Quick Specifications
| Parameter | Specification |
|---|---|
| Model | TT-A27H / TT-A27Y-P/R |
| Product Type | Spring-Loaded Low-Lift Safety Valve |
| Size Range | DN15–DN80 |
| Connection | Threaded |
| Design | Direct Spring-Loaded |
| Lever | Yes |
| Applicable Media | Water, air, steam or corrosive media depending on model |
| Maximum Operating Temperature | ≤200°C |
| Function | Overpressure Protection |
| Manufacturer | THINKTANK |
How It Works
The TT-A27H/Y is a direct spring-loaded safety valve.
During normal operation, spring force keeps the valve disc seated against the valve seat. When the pressure in the protected system reaches the specified set pressure, the pressure force acting on the disc overcomes the spring force and the valve begins to open.
The process medium is then discharged to reduce system pressure and protect the connected equipment or piping from excessive pressure.
As the system pressure decreases to the reseating range, spring force moves the disc back toward the seat and the valve recloses.
The valve is equipped with an external lever mechanism associated with the lifting assembly.
Typical Applications
The TT-A27H/Y Series can be considered for:
- Steam piping
- Compressed air systems
- Water systems
- Process equipment
- Small pressure vessels
- Packaged equipment
- Skid-mounted systems
- Utility piping
- Corrosive process service with a suitable TT-A27Y-P/R configuration
Final selection must be based on the actual medium, set pressure, temperature, 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 specific valve model, project specification and applicable standard.
For the TT-A27H/Y Series, the low-lift criterion applies: H ≥ 1/20 d₀.
Dimensions
| DN | Orifice d₀ (mm) | R Thread | L (mm) | L1 (mm) | G Thread | H Approx. (mm) |
|---|---|---|---|---|---|---|
| 15 | 10 | 1/2″ | 40 | 65 | 1/2″ | 135 |
| 20 | 15 | 3/4″ | 45 | 65 | 3/4″ | 140 |
| 25 | 20 | 1″ | 45 | 76 | 1″ | 155 |
| 32 | 25 | 1 1/4″ | 55 | 85 | 1 1/4″ | 170 |
| 40 | 32 | 1 1/2″ | 60 | 90 | 1 1/2″ | 310 |
| 50 | 40 | 2″ | 67 | 105 | 2″ | 322 |
| 65 | 50 | 2 1/2″ | 76 | 115 | 2 1/2″ | 344 |
| 80 | 65 | 3″ | 110 | 145 | 3″ | 395 |
Dimensions are for preliminary engineering reference. Final approved dimensional drawings should be confirmed before piping fabrication or installation.
Safety Valve Selection
A safety valve should not be selected only according to the nominal connection size.
For correct selection of the TT-A27H/Y Series, please provide:
- Process medium
- Set pressure
- Operating pressure
- Operating / relieving temperature
- Required relieving capacity
- Back pressure
- Inlet and outlet connection
- Required materials
- Applicable standards or certification requirements
- Installation and discharge arrangement
For gas or steam applications, additional thermodynamic data may be required for relieving capacity calculations.
Engineering Support
THINKTANK supports EPC contractors, system integrators, equipment manufacturers and industrial users with:
- Safety valve sizing and selection
- Set-pressure configuration
- Relieving capacity review
- Material selection
- Dimensional drawings
- 3D models for system integration
- Replacement valve evaluation
- Project-specific technical documentation
With more than 30 years of industrial valve application experience, THINKTANK can also evaluate equivalent replacements for existing safety valve brands and provide technically suitable, cost-effective alternatives.
