Top Entry Rising Stem
model A31
In a rising stem ball valve the stem lifts and rotates the ball away from the seat instead of rotating it against the seat: during opening and closing there is no rubbing between sealing surfaces. Combined with a single metal-to-metal seat with hardfacing, this makes the rising stem design suitable for frequent cycling, dirty or abrasive media and long-life severe service, with minimum seat wear and low maintenance.
The Valland rising stem ball valve (model A31 rising stem execution) is built on a single-piece, top entry body with bolted bonnet, designed to API 6D, API 6DSS or API 6A. Manual operation is by handwheel or gearbox; pneumatic, hydraulic, electric and electro-hydraulic actuation is available. Hyperbaric testing for subsea application can be performed.
A recent reference is the NPS 10 rising stem ball valve (model A81 execution) supplied to Ørsted for the Nybro lifetime extension of the Tyra terminal gas infrastructure in Denmark, with body in LCC low-temperature cast steel and stainless steel trim with Stellite hardfacing.
| Applicable standards | API 6D, API 6DSS or API 6A Design according to ASME B16.34 or ASME VIII Div. 1 & 2 |
| Pressure Class Range | ANSI Class 150 lbs. to 4500 lbs. API6A Class 3000 PSI to 15000 PSI |
| Size Range | API 6D, API 6DSS - from 1/4” to 24” API 6A - from 1.13/16" to 13.5/8" |
| Ends design | Flanged (RF/RTJ) - ASME B16.5 or ASME B16.47 Flanged (6B/6BX) - API 6A Compact (Norsok Standard L-005) Butt-Weld (ASME B16.25) and/or Butt-Weld + Pipe Hubbed according to client Clamp Special client's requirements |
| Body Design | Single piece |
| Closure Design | Bolted Bonnet |
| Seat design | Single Seat, Metal to Metal (c/w hardfacing) |
| Valve operation | Manual: Handwheel or Gearbox Actuated: Pneumatic / Hydraulic / Electric / Electro-Hydraulic |
| Available Materials | CS, LTCS, SS, Duplex SS, Super Duplex SS, 6Mo, Inconel, Incoloy, Hastelloy, Monel, Titanium NACE MR0175 according to client request |
| Additional Features | Reinforced Graphite or V-Pack stem sealing arrangement |
| Testing and Certification | Testing: Hydrostatic, High Pressure Gas, Pneumatic and Functional API 598 - API 6A PSL3G, API 6A PR2 & Endurance Fire testing: API 6FA, API 607, BS 6755 part 2 Fugitive Emission Test: ISO 15848 - 1 & 2 PED 2014/68/UE Mod.H Hyperbaric Test for Subsea application Additional test according to customers requirements |
