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

Did you know we also offer Full Service for your EPM Out-of-Stack (OOS) diluting sampler?

has the service knowledge of this system that remains unmatched. We have been involved with the service and rebuilds for numerous OOS systems over the years. Despite the fact that many of these systems are racking up the miles, we are doing our part to ensure that these instruments are running better than ever!

Full Service & Rebuilds

Pressure & Temperature Modifications

Several Upgrades Available

Many Spare Parts Available

EPM Out-of-Stack Diluter Seal Upgrade
To Eliminate Leakage and Sample Contamination

The original EPM Environmental Model 797.380 Series OOS (Out Of Stack Diluting Sampler) used a Kalrez® O-ring to create the seal between the diluter tip and the inner flange assembly. This configuration, using a Kalrez® O-ring, will limit the maximum operating temperature of the instrument to 572°F (300°C).

As application requirements became more demanding of greater temperature flexibility, it was decided to introduce a new Series OOS design having higher inlet sample temperature and/or heater set-point temperature capabilities.

In 1999, EPM had made a design change to the standard OOS Diluting Sampler to accomplish this. The design change consisted of the following:

1. Elimination of the Kalrez® O-ring from the design. In its place would be a 3/4" Swagelok® ferrule configuration (stainless 316).

2. Modification to the diluter side of the inner flange assembly to accept the ferrules that are permanently swaged to the diluter tip.

3. Larger inside diameter of the heater mantle, so that the diluter (with 3/4" Swagelok® nut permanently attached) could pass through it.

4. Sleeve/housing attached to the outside of the diluter, to eliminate the resulting gap between the diluter and larger ID of the heater mantle.

5. Modification to the knurled nut (hand wheel), so that it fits over the 3/4" Swagelok® nut.

This design change allowed for the maximum operating temperature (sample gas temperature and/or heater set-point temperature) of up to 750°F (400°C). The new model became EPM's standard OOS known as the Model 797.380-S Series ("-S" in the model number denotes "Swagelok®" type diluter tip seal).

Although the design change was proven to be successful in high temperature applications, and applications where cold process or ambient conditions required higher set-point temperatures, some issues have surfaced with regard to using the Swagelok® seal method.

These issues are as follows:

1. Leakage around the diluter tip which results in ambient air being drawn into the sample chamber via the bypass pump and contaminating the sample gas.

2. Difficulty re-tightening the Swagelok® nut to the full 3/4 turn from finger tight (per Swagelok® specifications).

3. Requirement for routine leak-tight testing that is time consuming as the system is not closed-loop.

4. Cross-threading of the modified knurled nut and threads of the inner flange assembly.

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Alpha Suite Inc.  2020