G&O Diaphragm valve do not incorporate any stuffing box and are leaktight on all liquids, slurries, granular materials, powders, pastes, gases, acids etc..
Diaphragm (internal membrane) is supported during opening and closing, and is easily replaceable without any special tools.
The wide range of available elastomer materials enable an appropriate selection for each application and is a guarantee of perfect resistance to corrosion and abrasion.



  • Weir type, conveyed flow way
  • Flanges and dimensions acc. to ANSI/ASME B 16.10 and B 16.34, DIN 3202 F1, UNI PN6/10/16, BS 5152 and 4504, NPT and BSP threaded connection.
  • Size from 1/2" through 14"
  • Manual, pneumatic and electric operated.



  • Long diaphragm life: no metallic inserts to strain the elastomers
  • Diaphragm supported during opening and closing: hence the possibility of under vacuum operation
  • Quick and easy replacement of diaphragm
  • Epoxy painted, valve bodies protected with an anti-acid varnish



  • Spheroidal cast iron gs400
  • A216 WCB carbon steel
  • A352 LCB carbon steel
  • SS 304; SS 316; SS 316 L



  • Soft rubber
  • Hard rubber (ebonite)
  • ECTFE/HALAR
  • ETFE
  • PFA
  • PTFE
  • Galvanized (laid in an hot zinc bath)


  • Limit switches
  • Solenoid valve
  • Position indicator
  • Filter regulator
  • 3:15 PSI positioner
  • 4:20mA electropneumatic positoner
  • 4:20mA electronic transmitter of position
  • Mono/Triphase AC motor



  • Sewage and sludge
  • Corrosive chemicals
  • Paper coatings
  • Wet scrubber slurries
  • Abrasive sand slurries
  • Mineral slurries



    GS 51 - handwheel operated, size 1/2" through 14"
    GS 51 DIN - handwheel operated, size 1/2" through 12"
    Literature on request only
    GS 55 – handwheel operated, NPT threaded connection, size 1/2" through 3"
    GS 57 – security valve, to maintain the constant pressure of a fluid, size 3/4" through 4"
    Literature on request only



    SINGLE EFFECT ACTING - SPRING TO OPEN
    GS 52 - one cylinder, on request available with emergency handwheel (GS 52A), size 3/4" through 14"

    SINGLE EFFECT ACTING - SPRING TO CLOSE
    GS 53 - one cylinder, with emergency handwheel, size 3/4" through 8"
    GS 54 - one cylinder, with emergency handwheel and special ring nut for travel limit regulating., size 3/4" through 8"

    DOUBLE EFFECT ACTING
    GS 56 – one cylinder, size 3/4" through 12"
    Literature on request only