Quote / Technical Help Request


Please choose your request type below and fill out the form to the right.

Choose Request Type

Stainless Steel
High Purity 2-Stage Regulator

Series 3500


The Series 3500 two stage regulators are designed and constructed for both high purity and general purpose applications. While compact in design these regulators provide outstanding performance, comparable to most larger diaphragm competitive models. They are an excellent choice for use with ultra high purity gases or gas mixtures having a full cylinder pressure of 1000 psig or more. They are rugged and versatile enough for the laboratory or plant.


  • High purity diffusion resistant, metal diaphragm construction on both stages.
  • Encapsulated seats on both stages.
  • Diffusion resistant, stainless steel diaphragm packless control valve installed on outlet as standard.
  • Designed to pass an inboard helium leak-rate test of 1x10-9 cc per sec.
  • All parts ultrasonically cleaned prior to assembly.


The 3500 Series regulators are ideal for critical pressure reduction applications, where the precise control of pressure or flow is required. They are also very useful for controlling the pressure of gas mixtures containing corrosive gases, such as ammonia, hydrogen sulfide, sulfur dioxide, and low levels of the corrosive halogen gases, like chlorine.


  • Max. Inlet Pressure: 3000 psig
  • Operating Temp. Range: -40° to +185°F.
  • Flow Coefficient (Cv): 0.08 standard, 0.2 optional**
  • Inlet and Outlet: 1/4" NPT female
  • Outlet Valve Standard
  • Delivery Pressure Rise: 0.02 psig max per 1000 psi inlet pressure decay.
Stainless Steel High Purity 2-Stage Regulator Series 3500

Materials of Construction

  • Body: 316L stainless steel
  • Nozzle Assembly: 316 stainless steel
  • Seat:
    • 1st stage - Kel-F®
    • 2nd stage - Kel-F®
  • Diaphragm: stainless steel
  • Diaphragm Seal: Teflon®
  • Inlet Filter: stainless steel
  • Bonnet: nickel plated aluminum
  • Gauges: 316 stainless steel
  • Knob: aluminum - black anodized
EZ Mounting Bracket
EZ Mounting Brackets (see page 101).

How To Order***

Del. Press. Range
Del. Press. Gauge
Inlet Press. Gauge
3501-10-CGA* 5-10 0-30 0-3000
3501-25-CGA* 5-25 0-30 0-3000
3501-50-CGA* 5-50 0-100 0-3000
3501-100-CGA* 10-100 0-200 0-3000
3501-250-CGA* 25-250 0-400 0-3000
3501-500-CGA* 100-500 0-1000 0-3000
  • *Specify CGA Connection Number when ordering.
  • **Add “HF” to basic model number (i.e. 3501HF -25-CGA).
  • ***For panel mounting bonnet add “PM” to base number (i.e., 3501PM-50-CGA).

Outlet Options

 P/N Suffix
No Outlet Valve NV
1/4" Compression Fitting T4F
1/8" Compression Fitting T2F
1/4" NPT Male P4M
1/4" Hose Barb 4HB

WARNING: A Purge assembly (see pages 96 and 97) is strongly suggested when using the above regulators with any corrosive gas.