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Diaphragm high and low pressure line valve for HP & UHP gases - M8SI
Equipment for gas systems > Ultra high purity gas equipment > Springless diaphragm line valves
M8SI is a diaphragm valve for HP & UHP applications. Its springless design keeps the highest level of purity of the gas. The M8SI valve exists in low, medium or high pressure versions. Different actuation are available for purchase : multi-turn or quarter-turn handwheel, and pneumatic actuator. The multi-turn version is delivered with an open-close indicator handwheel. It can be mounted on a panel.
Key advantages
  • 100% Helium Leak Test performed
  • Assembling, testing & Packaging in cleanroom: Class ISO 4
  • Reverse seat design for high life cycle
  • Individual serial number for full traceability
  • Electropolished surface roughness per SEMI F19 UHP Grade
  • Fluid specific seat material as standard options
  • Low internal volume
  • 316L VAR® stainless steel double melt per SEMI F20 option available
  • Additional Multi-port options
  • 270° multiturn handwheel with open/close indicator

CONSTRUCTION MATERIAL

  Parts Material
Wetted parts Body SS 316L,VAR
Seat PCTFE, PVDF, VESPEL®
Diaphragm Phynox®
Non-wetted parts Backup diaphragm Phynox® 
Handwheel Aluminium
Actuator Body SS 316L or Aluminium
Others Stainless Steel and Alloys

SURFACE FINISH

S V
Ra 0.4 μm (15 μin) Ra 0.25 μm EP (10 μin)

TEMPERATURE RANGE

Seat (Actuation type) Temperature Range
PCTFE / PVDF (manual & pneumatic(1)) -40°C to +65°C (-40°F to +149°F)
Vespel® (manual & pneumatic(1)) -40°C to +150°C (-40°F to +302°F)

(1) -20°C pneumatic versions

VALVE VERSION / MAX. WORKING PRESSURE

Valve Max. working pressure
M8SI (LM) Multiturn handwheel(2)(3) 20 bar
M8SI (HM) Multiturn handwheel(2)(3) 240 bar
M8SI (LQ) Quarter turn handwheel(2) 20 bar
M8SI (HQ) Quarter turn handwheel(2) 240 bar
M8SI (BP) Pneumatically actuated(4) 10 bar
M8SI (HP) Pneumatically actuated(4) 240 bar

(2) FT (Panel Mounting) option available

(3) MSF LOTO option available

(4) -20°C pneumatic versions

MANUAL ACTUATION

Parts for all valve grades
Upper spindle Brass
Handle Aluminium
All others  Stainless Steel

PNEUMATIC ACTUATION

Parts
Actuator Body Aluminium / Stainless Steel
Piston Brass / Aluminium / Stainless Steel
O-ring NBR
All others Stainless Steel

All specifications subject to change without notice.

Specifications
Max. working pressureSee table above
Pneumatic actuator opening pressure5 to 7 bar
Temperature rangeSee table above
Flow capacity (cv)0.5
Nominal seat diameter8 Mm
Wetted volume< 1.6 cm3
Burst pressure> 700 bar
Certified max. helium outboard leak rate≤ 1 x 10-9 M bar l/s
Certified max. helium across the seat leak rate (at max. pressure)≤ 1 x 10-9 mbar.l/s
Certified max. helium inboard leak rate (at max. pressure)≤ 1 x 10-9 mbar.l/s
Dimensional drawings
DrawingDrawingDrawing
Product Configurator
 
Surface finish
Actuation
Porting configuration
Body material
Seat material
End connection
Options
M8SI
S
LM
2V1
I
K
V 3/8 F
FT
 
Ra 0.4 μm (15 μin)
Ra 0.25 μm EP (10 μin)
Multi-Turn Handwheel (20bar)
Multi-Turn Handwheel (240bar)
Pneumatically actuated (10bar)
Quarter-Turn Handwheel (20bar)
Quarter-Turn Handwheel (240bar)
Pneumatically actuated (240bar)
See page 26
SS 316L
Hastelloy®(2)
VAR(2)
PCTFE (Kel-F®)
PI (Vespel®)
PVDF
Metal face seal 3/8” - Female
Metal face seal 3/8” - Male non-Swiel
BWO 1/2”
BWO 3/8" mm
BWO 10 mm
BWO 12 mm
Compression tube fittings
Compression tube fittings
Compression tube fittings
Compression tube fittings
Panel Mounting
Electric limit switch(3)
LOTO
Constant bleed
(1) Add NO for normally open or NC for normally closed
(2) On demand
(3) On HP and LP actuators only
Downloadable catalogs, brochures
  • Download
    Ultra High Purity valves and pressure regulators
    Last update: May 17, 2021
    Available in: en/fr/cn
  • Download
    LOTO Locking Mechanism for UHP Line Valves
    Last update: May 17, 2021
    Available in: en
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