06-07-2012, 11:41 AM
INDUSTRIAL GAS LEAKAGE PROTECTION SYSTEM
LGEC017 - Industrial gas leakage protection system.doc (Size: 250 KB / Downloads: 102)
Gas and vapor sensors have many industrial applications. These applications include the detection of hazardous gas in the workplace for worker safety, enhanced control of the air-fuel mixture and feed in combustion of fuel, increased product yield and reduced waste in a product stream. These applications generally rely on individual sensors, which are installed to detect a single gas or vapor whose concentration may approach a harmful level. In this project we will create a unit with an array of sensors. Individual sensor can be installed at an individual location in the factory and can be integrated with one single controller unit to enhance quality and reduce cost. The controller unit can be located in the controller room and can provide accurate information regarding location and extent of the leakage.
Sensors
The development of microcontrollers and microcomputers has led to smaller versions of these analytical instruments. These instruments are very powerful, but they have some disadvantages, such as being very maintenance intensive. Further, these instruments are sensitive to adverse, corrosive environments and must be located far from the gas or vapor source in a climate controlled enclosure.
The ability of sensors to identify a target gas depends on several factors. These factors include the sensitivity of the sensor to other interfering gases and vapors, and a concentration of the target gas. The ability to resolve the target gas from other gases is called the selectivity. For example, an unreliable sensor does not provide correct indication of a gas amount when the concentration of an interferant is high. In practice, this limitation is avoided by using a sensor only where a high concentration of interferant is unlikely. This solution, however, limits the effectiveness and uses of a sensor.
DESCRIPTION
In this circuit we used MQ-6 sensor for gas leakage detection. MQ-6 sensor composed by micro AL2O3 ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive components. The enveloped MQ-6 has 6 pin, 4 of them are used to fetch signals, and other 2 are used for providing heating current. Here MQ-6 sensor is work on basics of combustion process, and output is given in variable voltage form, so, when LPG gas is leakage voltage at the output pin of MQ-6 is increased and we use IC2 (Op-amp LM324) as a comparator for compare the LPG leakage with respect to normal condition. Output of comparator is fed to IC1 microcontroller (ATMEL 89S8253) and corresponding coding LCD is display gas leakage at any of four location.
APPLICATIONS
•Gas leak detection system
•Fire/Safety detection system
•Gas leak alarm
•Gas detector
FEATURES
•High sensitivity LPG, iso-butane, propane
•Small sensitivity to alcohol, smoke
•Fast response
•Wide detection range
•Stable performance and long life
•Simple drive circuit
ADVANTAGE
•It is used in house as LPG leakage detection.
•It also detect alcohol so it is used as liquor tester.
•The sensor has excellent sensitivity combined with a quick response time.
DISADVANTAGE
•It is little sensitive to smoke, then in kitchen it is not perfectly response for LPG gas leakage.
•It work only when at 5V power supply is given.
•Its sensitivity depends on Humidity and temperature.