Leak Detection

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Catalytic Combustion Sensor 201G
Thermal Connectivity Sensor 201B

  • 100% Tested

  • Rugged Modern Design

  • Interchangeable with Existing CC & TC Sensors

  • Precise Header & Tube Alignment

    Delphian makes two types of sensors for combustible hydrocarbon detection: the model 201G, catalytic combustion type sensor, and the model 201B thermal conductivity type sensor.
    All sensors are tested for span in methane and offset in air only to make sure they meet controlled performance standards and to guarantee consistency. These sensors are direct replacements for the CC and TC sensors made by J.W. (Bacharach Instrument Co.) and Analytical Logging.
    Delphian's sensors offer several improvements over other hot wire sensors. A new header design reduces sensor damage from rig vibrations. Aluminum tubes replace conventional glass tubes to isolate the filaments and reduce breakage. Special care is taken to assure that the welds which attach the sensing coils to the headers are always made for optimum strength. New materials and a self-fixturing design ensure more precise header and tube alignment. These features assure a longer life and a more consistent performance.
    Both sensors may be used in a wide variety of electrical circuit configurations and flow cells to suit the user's requirements. Delphian tests sensors in a standard J.W. Flow cell using the circuit shown in Figure 2.

    A set of curves for the CC sensor shows typical performance at various voltage for several different gases and concentrations (see Figure 1). Delphian tests its CC sensors at 2.2 volts and its TC sensors at 1.7 volts. However, both sensors may be used at other voltages. As a rule, sensors life is increased at lower voltages but the sensor is more subject to poisoning and contamination. Conversely, at higher voltages, poisoning and contamination are reduced but so is sensor life.


All sensors are factory tested to be within the following tolerances:



Test Voltage

Max Offset % Methane in Air Signal Size Tolerance
(at one sigma level)

CC Sensor 201G


+- 65 mV


110 mV


TC Sensor 201B


+- 65 mV


80 mV


Figure 1
. This set of curves for the CC sensor shows
typical performance at different voltages for several
different gases and concentrations.

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