News Details

KaiNaFu Launches KNF-700G Underground Gas Monitoring System with TDLAS Methane Detection

Shenzhen, China — KaiNaFu has released the KNF-700 and KNF-700G underground gas monitoring system, an all-in-one detection terminal built for sewer networks, drainage pipelines, inspection wells and road manholes. The terminal combines tunable diode laser absorption spectroscopy (TDLAS) methane measurement with hydrogen sulfide, carbon monoxide, oxygen, barometric pressure, temperature and optional liquid level sensing inside a single IP68, explosion-proof housing.

Why Underground Networks Need a Dedicated Monitoring System

Confined underground spaces can accumulate methane, hydrogen sulfide and carbon monoxide while oxygen drops, often at the same time. Conventional electrochemical and catalytic sensors drift, saturate or fail in humid, condensing atmospheres, so maintenance teams end up visiting manholes for calibration instead of acting on real risk. Municipal operators, drainage contractors and smart-city projects therefore need an underground gas monitoring system that stays accurate for years without consumable sensor replacement or frequent site attendance.

The TDLAS methane channel of the KNF-700G reads the methane absorption line with a tunable laser, which gives excellent selectivity, no cross interference from humidity, dust or other gases, and no consumable sensor. The methane sensing element is rated for more than three years of service.

Five Parameters, One Compact Terminal

Instead of installing several separate instruments inside a narrow shaft, one terminal covers the full gas profile plus the physical conditions that drive gas accumulation:

Key Specifications

Designed Around Real Manhole Conditions

• More than two years of autonomous operation from a 3.6 V large-capacity lithium battery, so crews are not opening shafts for battery swaps every quarter.
• Air pump sampling that tolerates soaking water, combined with a housing designed for inspection wells and humid air.
• 4G transmission with strong adaptability to weak underground signal, plus a split antenna option that can be buried in a shallow slot and covered with cement or asphalt to restore the road surface.
• Alarm-driven reporting: default sampling every 30 minutes and one upload per 24 hours, with immediate online transmission when a threshold is exceeded (up to three times per day).
• Three years of free data traffic included, so deployment does not require a separate SIM contract negotiation.
• 15 ~ 20 cm below ground installation with an expansion-screw mounting frame, and a rotating arm option when the liquid level radar path is blocked.
• External expansion interface for additional sensing functions, and other gases available on request.

Supply and Support

The terminal is manufactured in Shenzhen, China and certified to IP68 with EX d IIC T6 Gb explosion-proof protection. Minimum order quantity is one piece, supply ability is 500 pieces per month, delivery takes 10 to 20 working days, and export packing uses cartons with shock-proof foam. Payment terms are T/T. Each unit carries a one-year warranty from the date of delivery.

About KaiNaFu

KaiNaFu designs and manufactures gas detection terminals for drainage, municipal and industrial safety applications. The KNF-700 and KNF-700G extend that portfolio into underground confined spaces, where long unattended endurance and maintenance-free sensing matter as much as measurement accuracy.