1. Manufacturer of combustible gas alarm device
1. Shenzhen Softcom Industrial Co., Ltd. was established in 1995 and is one of the professional manufacturers of combustible gas alarm devices in China. The company has a group of earliest production technicians in China and a sales team with rich practical experience.
2. Since its establishment in 2005, Dongying Pengyuan Petroleum Equipment Co., Ltd. has been expanding its service team and expanding its service fields thanks to the support and love of new and old customers.
3. Jinan Hengyao Electronic Technology Co., Ltd. is a high-tech enterprise specializing in R&D, production and sales of toxic and harmful gases and combustible gas detection equipment. Since its establishment in 2004, the company has been committed to providing customers with products, services and system solutions that meet their application security needs.
Second, the combustible gas alarm device selection
Combustible gas alarm is a kind of gas leakage detection and alarm instrument, which is often used in chemical plants, petroleum, gas stations, steel plants and other places with gas leakage. So how can we choose a combustible gas alarm with excellent performance? Here are four tips for choosing combustible gas alarms shared by Noan Bao Xiao!
1, depending on whether the combustible gas detector is stable. This is a factor that must be considered. The smaller the values of zero offset and full-amplitude offset, the better. All gas detectors will produce more or less interference reactions to other gases except oxygen, and the most common one is the electrochemical sensor for detecting hydrogen sulfide. Therefore, as daily users in home life, we must be familiar with the toxic gases that may exist in the family.
2. It depends on whether the combustible gas detector is easy to identify. Digital or pointer gas detector. Generally speaking, the advantages of numerical type are strong readability and less misjudgment. Whether the display area is large enough, with background lighting and large fonts for easy reading and understanding. Whether the alarm is loud enough to be distinguished from the background noise. Generally more than 90dB(A) is applicable. Whether the alarm flash can be recognized from all angles. Whether the signal can be displayed continuously with the change of the measured gas concentration, and stop the alarm after confirming or taking countermeasures.
3. It depends on the reliability of combustible gas detector. The longer the life of the sensor, the better. Generally speaking, the average life of combustible gas detectors is 2-5 years, and the smaller the error, the better. Accuracy and precision will improve with the increase of service life, and the warranty period of products is generally 2 years. Whether the sensor adopts intelligent sensor technology.
4. It depends on whether the combustible gas detector is convenient to use.
Three. Matters needing attention in application
Once the fixed-point installation of combustible gas alarm is in place, its position is not easy to change. According to years of accumulated work experience, the following points should be considered in specific applications.
(1) Find out the possible leakage points of the monitored equipment, analyze the leakage pressure, direction and other factors, draw the position distribution map of the probe, and divide it into three levels according to the severity of the leakage.
(2) According to the specific factors such as the direction of air flow and wind direction in the place, judge the leakage direction of combustible gas when a large number of leaks occur.
(3) According to the density of the leaked gas (greater than or less than air) and the air flow trend, the three-dimensional flow trend diagram of the leaked gas is synthesized, and the initial setting scheme is made at the downstream position of the leaked gas.
(4) Study whether the leakage state of the leakage point is micro-leakage or jet. If it is micro-leakage, the position of the set point should be closer to the leakage point. If it is jet leakage, it should be slightly away from the leakage point. According to these circumstances, the final plan was drawn up. In this way, we can estimate the quantity and variety to be purchased.
(5) For places with large combustible gas leakage, according to relevant regulations, a detection point shall be set every10-20m-20m. For the unattended small pump house running intermittently, attention should be paid to the possibility of combustible gas leakage, and detectors should generally be installed at the downdraft.
(6) For places with hydrogen leakage, the detector should be installed on the plane above the leakage point.
(7) For the medium with gas density greater than air, the detector should be installed on the lower plane below the leakage point, and pay attention to the characteristics of the surrounding environment. Special attention should be paid to the setting of safety monitoring points in places where flammable gases are easy to accumulate.
(8) For the open environment where combustible gas diffuses and escapes, if there is no good ventilation condition, it is easy to make the combustible gas content in a certain part of the air close to or reach the lower explosion limit concentration. These are security monitoring points that cannot be ignored.
According to the analysis results of on-site accidents, more than half of them are caused by incorrect installation and calibration. Therefore, it is necessary to introduce correct installation and calibration precautions to reduce failures.
Four. Precautions for installation of combustible gas alarm
(1) There should be no strong electromagnetic fields (such as high-power motors and transformers) around the alarm.
(2) The alarm is a safety instrument with acousto-optic display function, and should be installed in a place where the staff can easily see and hear, so as to eliminate hidden dangers in time.
(3) The installation height of the alarm should generally be160-170 cm, which is convenient for the maintenance personnel to carry out daily maintenance.
(4) The alarm probe is mainly a detection element contacting with the combustion gas sensor. It consists of platinum wire coil coated with alumina and adhesive, and rare metals such as platinum and palladium are attached to the outer surface. Therefore, care must be taken during installation to avoid damaging the probe.
(5) The installation position of the indoor probe should vary with the density of the gas to be measured. When the measured gas density is less than the air density, the probe should be installed 30cm away from the roof with the downward direction; On the contrary, the probe should be installed 30cm above the ground, with the direction upward.
(6) The installation height of the outdoor probe can be selected according to the density of the gas to be measured. It is particularly important to note that the probe should be installed on the downwind side.
(7) The connecting cable of the alarm circuit should be protected by a protective sleeve, and it is best to add a metal hose to the wiring of the probe, and pay attention to the ex-factory explosion-proof grade.
(8) After installation and debugging, be sure to install a breathable waterproof cover to prevent rainwater from entering and damaging the probe.
Five, combustible gas alarm calibration matters needing attention
(1) In principle, the standard sample gas that has been certified by measurement and matched with the detected gas should be used. Different standard sample gases are used for the same measured medium, and the alarm points are also different.
(2) Before calibration, there should be no gas around the probe. If there is combustible gas, the rain cover should be removed first, and a certain amount of clean air should be filled before the sample gas is continuously introduced to ensure the accuracy of calibration.
(3) When the measuring gas is a mixture of hydrocarbons, isobutane is the preferred sample gas, followed by propane.
(4) For non-hydrocarbon mixtures or gases with low explosive concentration, the heat generated during combustion is quite different.
For hydrocarbon mixture, butane, isobutane, propane and other easily available and stable single-component fuels can be used as sample gas if necessary. At this time, the alarm range must be adjusted according to some conversion relationship of the detection signal.
Six, the use and maintenance of combustible gas alarm method
There are many kinds and models of combustible gas alarms, but the basic circuit principle is the same, so their use and maintenance methods are similar. The usage and maintenance methods are as follows:
(1) The service life of detection elements and compensation elements is usually 3-5 years. Under reasonable conditions and proper maintenance, its service life can be extended.
(2) For the alarm with test button, press the test button once a week to check whether the alarm system is normal. Check and calibrate the zero point and range of the alarm every two months.
(3) Check the detector frequently for accidental water inflow. When testing the instrument, remove and clean the vent cover of the detector to prevent blockage.
(4) The detector is flame-proof and explosion-proof equipment and shall not be used beyond the specified scope. Detectors should not be used in sulfur-containing situations. The detector should be used under the condition that the concentration of combustible gas is lower than the lower explosion limit as far as possible, otherwise it may burn out the components.
(5) Hot-wire semiconductor detectors shall not be used under anoxic conditions. Don't use a lot of combustible gas to go straight at the probe.