High Purity Porous Metal Flow Restrictors

For reliable, affordable flow control, without the drawbacks of mass flow controllers, needle valves and calibrated orifices.
Whatever your priorities in flow control - whether you want low cost, consistent performance, or resistance to clogging - there's one alternative that will satisfy on all counts: Mott High Purity Porous Metal Flow Restrictors. Featuring Mott's unique porous metal media developed specifically for semiconductor manufacturing.
Mott Flow Restrictors provide compact, long-lasting flow control coupled with:
  • A cost-effective design - Mott's simple flow restrictor design consists of a porous metal element inside a standard fitting, providing maximum strength and reliability at a minimum cost.
  • Fixed, tamper-proof performance - Each Mott Flow Restrictor delivers the specified downstream flow for the life of the product. There are no moving parts or potential adjustments which can hamper performance.
  • Clog-free performance, with laminar flow - The porous metal element spans the full width of the inner channel, allowing gases to move through hundreds of microchannels without increasing flow velocity or creating irregular flow paths. Downstream flow is smooth and constant, and the media will not wear from friction, or clog when exposed to sporadic particles.
Additional benefits of Mott Flow Restrictors
  • All-metal construction - Porous metal elements constructed of 100% stainless steel, nickel or Hastelloy¨ are permanently affixed into 1/4" face seal fittings. Other configurations are available. There are no elastomers or other non-metallic materials which could flex or shed particles.
  • Tolerance of high temperature and pressure - Stainless steel Mott Flow Restrictors withstand sustained temperatures to 450°C (inert gas), and pressures to 120 psig, standard; up to 1500 psig by request.
  • Wide range of flow rates - Downstream flows range from 100 SLPM to <1x10-6 SCCM.
  • Cleaned and bagged in a Class 100 clean room - For superior out-of-box performance.
  • Calibrated - To nitrogen and hydrogen flow curves. Compatible with all process gases including oxygen. Sized to specialty gas applications through viscosity curves.
Major advantages over calibrated orifices
  • Reduces the flow burden - From one pore to hundreds
  • Prevents plugging - By distributing flow over the entire insert
How to determine the flows of other gases
The flows of gases not yet tested with Mott Flow Restrictors can be estimated by adjusting for the viscosity relative to nitrogen. Ratios of some common process gases are shown in the table below. To make the correction between nitrogen and the target gas, use the following formula:
Nitrogen flow = (target gas flow) x (target gas viscosity / N2 viscosity)
418 SCCM of N2 = 500 SCCM HCl (148/177)

Standard orifice:
Speed, pressure and heat increase as gas moves through the orifice, causing wear and tear.

Flow restrictor:
Gas moves uniformly through porous metal element with minimal friction due to viscosity.

© 2022 Rainer Lammertz