Heated Thermal Desorption Sampling Chambers

Description

For sampling of volatile and semivolatile organics from large samples at elevated temperatures

Standard Chamber (Complete) and Standard Chamber with heated cover removed.

The Heated Thermal Desorption Sampling Chambers are used to contain large solid matrix samples for the purpose of purging off the volatile and semi-volatile organics at elevated temperatures and then trapping these analytes on thermal desorption tubes packed with a variety of adsorbent resins. The samples collected are then analyzed using the thermal desorption system in conjunction with a GC and/or GC/MS. The chamber shown is 4" in diameter x 4" high and can analyze samples up to 3.0" diameter x 1.5" high. These systems are custom made on order and other chamber sizes can be constructed according to your requirements.

Two models of the 4" Sample Chamber are available - Standard and High Temperature. The Standard Model is constructed using an NW type flange with a PTFE encapsulated sealing ring (max temp 250 degrees C) and a quick disconnect clamp. The High Temperature Model is constructed using a standard Conflat flange with a copper sealing ring (maximum temperature 450 degrees C) and the chamber is clamped using standard 1/4" diameter bolts.

The system shown contains two heaters. Both heaters contain a J type thermocouple for the measurement of the temperature at the heater surface. The system requires two separate temperature controllers one for each of the heater circuits (these must be ordered separately). The interior plate heater is used to directly heat the sample on top of this plate inside the sealed chamber. This heater can be heated up to 800 degrees C. The external heater is used to heat the sample chamber to prevent the condensation of volatiles on the surface of its walls. This heater is also used to heat the chamber to higher temperatures in order to bake it out between samples. The maximum temperature for heating the walls is dependent on the material used to seal the two halves of the sample chamber (Standard Model is 225 degrees C and High Temperature Model is 450 degrees C).

The systems shown contain an adjustable internal purge gas nozzle that can be positioned or replaced with another style to suit the users needs. The purge gas can be adjusted from 0 to 1000 mL/min using a separate gas flow controller (not included).

The system is designed to accept any 1/4" diameter thermal desorption tube including 1/4" glass tubes as well as the SIS GLT thermal desorption tubes. The desorption tube is attached to the top of the chamber using the 1/4" Swagelok fitting with either PTFE or Graphitized Vespel® seals.

Theory of Operation of the Desorption Sampling Chamber

Features

Standard 4" TD Sampling Chamber

Features

• NW Type Flange with Quick Seal Clamp
• PTFE encapsulated O Ring Seal
• Maximum housing temperature - 225 degrees C
• Max Sample Size: 3" diameter x 1.5" high
• Maximum Sample Temperature- 800 degrees C
• Requires 2 Temperature Controllers
• Requires Separate Flow Controller
• Accepts any 1/4" diameter desorption tube
• Maximum purge flow - 1000 mL/min

High Temperature 4" TD Sampling Chamber

Features

• Conflat Type Flange with 1/4" clamping bolts
• Copper Ring Seal
• Maximum housing temperature - 450 degrees C
• Max Sample Size: 3" diameter x 1.5" high
• Maximum Sample Temperature - 800 degrees C
• Requires 2 Temperature Controllers
• Requires Separate Flow Controller
• Accepts any 1/4" diameter desorption tube
• Maximum purge flow - 1000 mL/min