What type of device consists of a spring-loaded bellows with a capacity of 50 or 100 cc of air?

• A. Gas chromatograph
• B. Gastec detector
• C. Photoionization detector
• D. Electrochemical sensor

Answer: (B)

The correct choice identifies a Gastec detector, which is specifically designed to use a spring-loaded bellows to draw a specific volume of air—typically 50 or 100 cc—into a sampling tube for the detection of various gases. This mechanism allows for a precise and consistent method of sampling air to analyze pollutants or hazardous substances.

Gastec detectors are widely used in various industries for monitoring environmental conditions and ensuring safety, as they provide immediate qualitative and quantitative results for specific gases. The spring-loaded bellows ensures a reliable and reproducible sample size, which is crucial for accurate detection and measurement.

In contrast, gas chromatographs separate and analyze compounds in gas mixtures but do not use a bellows mechanism or operate on the principle of fixed air capacity sampling in the same way as Gastec detectors. A photoionization detector measures gas concentration through ionization but does not feature a bellows mechanism for air sampling. Lastly, electrochemical sensors work on the principle of chemical reactions with target gases but do not utilize a bellows or fixed volume approach.

Understanding this device's specific function and construction is essential for correctly identifying it in practical scenarios within mine safety and monitoring processes.