These electronic leak detectors are used to detect leaks in circuits containing refrigerants or combustible gases, by detecting the presence in the atmosphere of the gas escaping through the leak.
Kimo Sauermann leak detector
These portable devices are almost always fitted with a flexible hose, enabling them to inspect all leak-prone areas of a circuit, even those that are difficult to access.
Several types of detectors are available: ionization detectors, heated diode detectors, and infrared detectors.
Ionization detectors
This is the oldest electronic detection technology. These detectors draw in ambient air via a built-in micro-pump and send it into an ionization chamber equipped with oppositely charged platinum electrodes.
When halogenated refrigerant gas from the leak passes through the chamber between the electrodes, it is ionized and causes a change in the electric current.
Advantages:
- This detector works with all halogenated refrigerant gases.
- It is inexpensive compared with more recent technologies.
Heated diode detectors
For this type of detector, a ceramic diode sensor is located at the end of the hose. This diode is heated to a temperature corresponding to the gas to be detected. The diode reacts to the presence of halogenated refrigerant gas by producing fluoride ions from the gas molecules, thereby modifying the electrical current flowing through it. This electrical signal is sent to the device’s electronics, which triggers an audible and visual alarm.
Heated diode electronic detectors can detect both low and high concentrations of gas, and some models offer sensor temperature adjustment for precise detection of certain gases. These detectors deliver progressive signals as a function of gas concentration, enabling the search to be directed right up to the leak. These detectors are more sensitive to interference from other gases in the ambient air and may trigger false alarms. They can also become overloaded if the ambient air is saturated with gas from the leak.
Advantages:
- This highly sensitive detector can detect even low concentrations of gas. What’s more, the detector’s sound signals are progressive, enabling it to pinpoint the area of the leak where gas concentrations are highest.
- Like ionization detectors, these are compatible with all halogenated refrigerant gases (CFC, HFC, HCFC).
Disadvantages:
- As this detector is very sensitive, it can sometimes trigger false alarms.
- In areas saturated with refrigerant gas, the sensor may be overloaded.
- The sensor has a service life of 100 hours.
Infrared detectors
Infrared leak detectors draw air through an optical sensor; refrigerant gas alters the amount of infrared transmitted to the sensor, and the detector electronics trigger an alarm. Infrared detectors are considered better than the previous two because their sensor can last up to 10 years, they are not overloaded in a gas-saturated environment, and they are less prone to triggering false alarms. On the other hand, they are more expensive to buy. Infrared electronic detectors work with all CFC, HFC, and HCFC refrigerant gases.
Advantages:
- These are considered the most reliable for detection.
- The sensor has a life expectancy of 10 years.
- Less prone to false alarms.
- Not overloaded in gas-saturated zones.
- They also work with all types of refrigerant gas.
Disadvantages:
- More expensive than the other two types of detectors.