Gastec HS-7A-S Hydrogen Sulphide Detector

Description

The HS-7A-S utilizes a high-performance electrochemical sensor. When gas is drawn into the unit via the internal pump, it reacts with the sensor’s electrode, generating a small electrical current proportional to the gas concentration.

This model is favored by technicians because of its “Direct Read” capability—providing an immediate digital display of the $H_2S$ concentration without the need for colorimetric tubes (though Gastec is famous for them). Its built-in pump allows for “Pre-Entry” testing; a technician can drop a hose into a confined space to check for $H_2S$ before physically entering the area.

Brand

Gastec

Although, technology is always evolving, one demand on our products never changes: the demand for customer safety. Whenever we contribute to customer safety, we are presented with an opportunity to develop further.

GASTEC holds this corporate creed of safety and development in high esteem, as it strives to grow while always putting customer safety first.

Features

Built-in Suction Pump: Enables remote sampling via extension hoses, making it ideal for checking manholes or deep tanks from a safe distance.
Dual-Range Monitoring: Usually features a low range (0–30.0 ppm) for high-resolution environmental checks and a high range (0–100 ppm) for industrial leak detection.
Fast Response Time: Provides a $T_{90}$ response (90% of the actual value) in less than 30 seconds.
Large Digital Display: Clear LCD screen that shows real-time concentrations, battery status, and peak values.
Audio-Visual Alarms: Equipped with a loud buzzer and flashing LEDs that trigger if gas levels exceed pre-set safety limits (typically 10 ppm for the first alarm).
Compact & Lightweight: Designed for one-handed operation with a rugged exterior to handle field use.

Specifications

Feature	Specification
Gas Detected	Hydrogen Sulphide ( $H_2S$ )
Detection Principle	Electrochemical Cell
Sampling Method	Internal Diaphragm Pump
Detection Range	0 – 30 ppm (Standard) / 0 – 100 ppm (Extended)
Resolution	0.1 ppm
Operating Temp	-10°C to +40°C
Battery Life	~8–12 hours of continuous operation
Weight	Approx. 300g – 450g (including batteries)

Applications

Wastewater Management: Checking for $H_2S$ “hotspots” in sewers and pumping stations where organic matter decomposes.
Pulp & Paper Industry: Monitoring emissions near digesters and washers where $H_2S$ is a common byproduct.
Confined Space Entry: Ensuring a safe atmosphere for workers before they enter underground vaults or storage vessels.
Landfill Monitoring: Detecting surface emissions or migration of landfill gases.
Chemical Plants: Routine leak detection around valves, flanges, and seals in $H_2S$ processing lines.