Leak Detectors

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Leak detectors cause leak prevention, which is a crucial part of the industrial sector. Many different industries have leak problems, and thus need reliable and accurate leak detection equipment to eliminate health and safety risks that leaks often cause. In the medical industry, leaks can be found in pumps, containers, fluid transfer devices and other instruments that may play a crucial role in the lives of patients. Other industries, such as the scientific and automotive, use leak detectors on measuring equipment, water pumps, cylinder heads, calibrated volume vessels and hydraulic components. Having problems with leaks can not only cause a system to malfunction, but can also be hazardous to health, depending on what chemical or gas is being dealt with. Because of this, leak detectors play an important role in many fields today. Leak detection is identified by 4 main types of equipment: electronic leak detectors, ultrasonic leak detectors, flame ionization leak detectors and gas detectors, such as helium leak detectors. Different gas detectors identify certain types of leaks, such as refrigerant leaks like Freon, natural gas, halogen or vacuum leaks. Gas analyzers and leak testers are also available to aid in determining the specific composition of the leaking gas, although they are unable to locate the exact location of the leak.

Using electronic leak detectors is the fastest way to identify or locate a gas leak. There are 2 main types of electronic detectors, those that use a heated diode and those that use corona discharge. The detectors that use a heated sensor are less prone to false alarms as opposed to corona discharge, which can be set off by dust, moisture or solvents. Ultrasonic leak detectors are fairly new to the leak detector industry and are mostly used for larger gas leaks. They are able to convert the quiet, high-frequency noises that gas leaks make into a louder, lower range that is heard through headphones and audible to the human ear. Gas detectors use a tracer gas, often helium or hydrogen, to help detect other gasses. After the tracer gas is pumped into the system with a potential leak, the gas detector measures the rate of the leak via a mass spectrometer, which provides test sensitivity. Finally, halide torch leak detection uses flame ionization to detect chloride refrigerant leaks exclusively. If a halogen refrigerant is present, the color of the torch flame changes from blue to green. Some equipment, such as leak testers and gas analyzers, are only able to perform one of function. Gas analyzers are able to detect the composition of a specific gas. They can confirm the existence but not the exact location of the leak. These are useful for defining and monitoring mass spectrometers. Exhaust analyzers test the exhaust of machines and vehicles and are the most common type of analyzers. Infrared analyzers monitor CO2 gas, while combustion analyzers monitor installations and measure CO2 and flue gasses. Residual analyzers are suited to monitor contamination and process control, specifically in the semiconductor industry. Leak tester equipment is used to detect the existence of a leak, but not the type of gas. They test for differences in pressure and use flow measurement.

These different types of leak detection equipment are all used to find leaks of different gas varieties. Refrigerant gasses are compounds that often leak out of refrigerators, freezers and air conditioning equipment. Freon is the brand name given to a whole class of chemicals used in older refrigeration systems that, if leaked out, may cause heart problems for those that breathe it in as well as deplete the ozone layer. In the home, natural gas leaks are a huge concern. Natural gas is a common energy source used for heating, cooking and water heating. It is composed of the highly flammable methane gas, and could start an explosion or massive fire if it is leaked and comes in contact with any sort of spark or flame. If methane gas is inhaled in large quantities, it can also be fatal. Therefore, it is important for any heating system that uses natural gas to have permanent detectors. Many of these have sound or light alarm systems and varying degrees of sensitivity. Some will only detect the lowest amount of methane gas in a room that could cause a fire or explosion, and many systems release a rotten egg smell if a leak occurs. Vacuum leaks can occur in car engines, furnaces and in automobile manufacturing. These leaks are generally detected and located with helium gas.

Most leak detectors are hand-held devices that are programmed to monitor specific conditions. The mobility of the leak detectors is important because of the tight and complex networks of piping that are sometimes used to house a gas or a liquid. Most methods of leak detection are operator dependent. Some systems, however, such as those used to detect water leaks, are able to monitor changes in atmospheric conditions without the use of an operator. Unfixed leaks are a major source of economic loss in both the residential and industrial spheres. Leaking liquids and gases can damage surrounding equipment, and neglected leaks are a major health concern for people who inhabit a factory, work or home environment where one is present. Water leaks left unchecked create mold and therefore manifest many allergic responses in employees or customers exposed. The refrigeration industry is very concerned with the efficient and quality detection of leaks, as many of the chemicals, such as the now outlawed CFC (chlorofluorocarbon), can be found in many older refrigeration units still in use.

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Leak Detector Types

• Alarm only leak detectors give off an alarm when they detect gas, but do not give any information about the type or amount.
  
• Colorimetric leak detectors react chemically with minute leaks and cause a visible color change in the developer.
  
• Electronic leak detectors can be programmed to detect certain or multiple refrigerants. After the general area of the leak is detected, a soap solution is applied to the area to reveal the precise leak point.
  
• Freon leak detectors monitor products that use the chemical Freon in order to ensure that the chemical, which can be dangerous, remains contained and the product functional.
• Gas analyzers detect the composition of a specific gas. When a gas leak is suspected, the analyzer can confirm the existence of a gas compound in an environment, but cannot pinpoint the exact location of the leak.
  
• Gas detectors use tracer gasses like hydrogen and helium to find a leak. After filling the chamber with helium or a hydrogen/nitrogen mix, the gas loss is measured with a mass spectrometer that detects the helium or hydrogen.
  
• Halogen leak detectors are used to detect and identify the location of halogenated refrigerant leaks.
• Helium leak detectors use helium to pinpoint the source of a leak.
• Leak detection measures the discharge of gases and liquids to find leaks.
• Leak testers are mechanisms designed to detect and measure predominantly liquid and gas leaks.
• Natural gas detectors monitor the amount of methane in a given area and, when the gas is detected, trigger an alarm to signify that there is a leak.
• Refrigerant leak detectors can detect only chlorinated refrigerants. A halide torch uses a flame, and if halogenated refrigerant vapors are present, the flame changes from a blue to blue-green color.
  
• Ultrasonic detectors are used to detect a wide range of gas leaks. Because gas leaks are noisy, this technology converts the high frequency leak sound to a lower range where the hissing of the leak can be heard through a set of headphones and traced to the source.
  
• Vacuum leak detectors identify leaks in closed systems using compressed air to monitor the changes in pressure, which indicates the presence and severity of leaks.
• Water leak detectors range from sensors that monitor moisture levels to sensors that monitor flow rates and all have warning alarms and auto shut-off devices.

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Leak Detector Terms

Adsorption - The condensation of gas or vapor on a surface.
 
Aerosol - The suspension of minute particles in the air.

Analyzer - An instrument that can determine qualitatively and quantitatively the components in a mixture.

Blocking - The conditions that cause leak detectors to malfunction, most commonly a lack of oxygen.

Calibration - The procedure used to adjust an instrument for proper response.
 
Combustion - The rapid oxidation of a material that is evolving heat and light.
 
Explosive/Flammable Range - The range of flammable vapor or gas-air mixture between the upper and lower flammable limits.

Gas - A type of matter that expands indefinitely to fill a contained space. Gas is characterized by its low density.

Interference - A gas other than the one being detected that will cause a false reading on a leak detector.

Leak Tight - Leakage that is at an acceptable rate for a system or component.

Non-destructive Testing (NDT) - The examination of an object or material with technology that does not affect the object's future.
 
Permeation Leak - A leak through a barrier that does not have a hole or a discrete passage.
 
Quantitative - The total amount of leakage for any particular system or component.

Sensor - A device that converts the presence of a gas or vapor into an electrically measurable signal. The sensor is the heart of a gas monitor and can also be used to detect other substances, such as moisture levels.

Toxic Gas or Vapor - Any substance that causes sickness or death when inhaled or absorbed by the body.

Tracer Gas - A gas that, when passing through a leak, is used by a specific leak detector to help detect the presence of other gasses.

Vapor - The gaseous state of a material below its boiling point.
 
Zero Gas - Clean air, and a way of ensuring that a small release of gas is not near the sensor when honing the sensing signal during calibration.

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