Quality Instruments, Spare Parts, Service & Support from your Gas Sampling Specialists at ASI
Experience and Expertise from Hundreds of Reconditioned and Repaired CEMS Dilution Probes

Fast and Consistent Turnaround Times for your Serviced Equipment


We have a wide range of standard Critical Orifice (sonic orifice) styles and flows to suit your diluting application. Critical Orifice styles for use with your in-situ and out-of-stack diluting sample probes, our ESP direct extractive probes, inertial filter diluting probes, laboratory diluters and more.

Standard Materials include Glass, Quartz, Monel-400®, and Stainless 316. Standard Max. Temperatures up to 750°F (400°C), High Temperature Critical Orifices (Sonic Orifices) are available for your applications up to 1000°F (540°C).

For our OEM Customers, we offer custom designed critical orifices to meet your specific needs.

ASI is a proven leader for Quality Parts and Best Selection of critical orifice flows and materials you will find for your gas sampling instruments and systems.


Cross reference the old EPM critical orifice part numbers

Alpha Suite Inc.  2020