ISO FSN-HF Acid Service Valve – Two-Way Plug Valve for Harsh Conditions

Two way plug valve with safety stuffingbox packing, special design for HF alkylation, Monel materials

Type ISO-FS-HF with Fire Safe sealing
Type ISO FSN-HF with  triple safety sealing for fluctuating temperatures

ASME: NPS ½“ – 24“ / class 300
PT range: -29 < T < 220°C

Design Features

Design Characteristics

  • safety stem packing
  • easily accessible plug adjustment
  • UOP approved design for HF Alkylation
  • free of cavities
  • maintenance free / self lubricating
  • HF detection coat for leakage indentification
  • actuator mounting flange acc. to DIN ISO 5211

Approved for the highest HF Alkylation UOP Process Specifications

  • AZ HF plug valves are specially designed for the use in any HF Alkylation processe and hydrofluoric acid applications
  • design and material requirements as well as manufacturing and testing procedures are in accordance to the UOP process and piping specifications HF1, HF10, HF2 and HF20

Operating temperatures < -29°C and > 220 °C have to be checked and approved by AZ according to the operating conditions.


Standard body material

  • Monel, ASTM A494 M35.1

Standard plug material

  • Monel, ASTM A494 M35

Standard cover material

  • ASTM A216 / WCB (Monel, ASTM A494 M35.1 on request)
Sealing Systems

Type FS-HF

Firesafe sealing (API 607) with graphite packing for additional stem sealing; Tmax 220°C


Firesafe safety sealing (API 607) for fluctuating temperatures
with 3x graphite packing (adjustable) for additional
stem sealing, Tmax 220°C

Port Forms

Fully vented Plug (FVP) prevent possibility of pressure build-up due to thermal expansion

  • vented plug buttom
  • vented plug side




1 Locking Devices
Pilot valve combinations, pad lock eyelets, linear key conception, indexing plunger arrestor.

2 Plug stem extension
Solid construction in stainless steel with T-wrench, Standard extension 100 mm or 150 mm, non standard lengths are available on request

3 Actuators
Actuators for mounting-flange acc. to DIN ISO 5211

NEW: Pneumatic actuator AIR GEAR for plug valves with high torque =150.000 Nm

4 Ratched coupling
To usw on multiport valves with standard 90° actuator for bigger switchpositions than 90°

5 Cover extension
Solid construction in stainless steel, Standard extension 100 mm or 150 mm high,  non standard lengths are available on request . Hexagonal bolts on adjustment ring freely accessible. Note: Don’t use with sealing FSN/FSN-SL and CASN/CASN-SL