Qualification requirements of gas leakage alarm manufacturers
The State Fire Bureau implemented the product form approval for the production enterprises of gas leakage alarms, and issued long-form approval marks for the form approval certificates. Products that are not approved and that have not been affixed with an accreditation mark may not be sold on the market.
Gas leak alarm performance requirements
Gas leak alarm performance must meet the GB15322-2003 "combustible gas detector technical requirements and experimental methods", CJ3057-1996 "home gas leak alarm" standard requirements, used in the Shanghai area should also meet DB31/89- 1997 Requirements for Safety Technical Conditions for Flammable Gas Leakage Alarms. Gas leak alarm performance requirements are mainly from the sensitivity, selectivity, stability, service life and other aspects into the assessment.
Gas leak alarm sensitivity requirements
Sensitivity is the most important indicator reflecting the performance of the alarm. It is generally set according to the lower explosion limit of the flammable gas (the lowest concentration of combustible gas and air explosion), and the low limit alarm setting value should be around 50% LEL. An alarm setting value should meet the low limit alarm setting value. Monitoring different gas, the sensitivity of the alarm set value is not the same, so in the selection, you must find out what kind of gas used in the alarm installation site, and then use a targeted alarm. At present, the exhaust gas generated from the combustion of gas appliances contains CO, and CO has a great harm to the human body. Therefore, home users in the selection of alarms, it is best to use the detector alarm, both for the gas leak alarm, but also for the CO over the alarm, play a double insurance role.
Gas leak alarm selection requirements
When the alarm is required to have high sensitivity, it must also prevent false alarms. That is, the alarm should not be reported at the time of the report, and should not be reported at the time of reporting, thus adding to the use of trouble. Therefore, the detector requiring the alarm should have a high selectivity to the gas to be measured in order to distinguish the interferences of smoke, paint, organic solvent vapor and the like.
Gas leak alarm stability requirements
Gas alarms are generally installed in harsh environments. For places such as the field, kitchen, basement, and boiler room, the temperature and humidity of these places are relatively large, and the performance of the alarm should be protected from these factors and real-time monitoring.
Life of gas leak alarm
The life of a gas leak alarm depends on the life of the detector. The current lifespan of the detector is generally 3-5 years. During this period, the performance of the alarm should meet the requirements.
Alarm production or sales companies must have honest and reliable after-sales service mechanism
As a safety product for preventing gas accidents, gas leak alarms have a major role to play and their performance is affected by many factors. Therefore, a production and sales company must have an honest and reliable after-sales service mechanism that can schedule alarms on schedule. Perform maintenance and maintenance.
The use of gas leak alarms
Gas leak alarms are based on different models and grades, and their prices are relatively large. The cost-effectiveness should be considered when selecting gas leak alarms. General domestic use is cheaper than industrial use, non-explosive is cheaper than explosion proof, semiconductor type is cheaper than catalytic combustion type, single type is cheaper than centralized control. Since the detector has a useful life, it must be replaced on a regular basis, so the cost of replacing the detector should also be considered.
Turbine Centrifugal Fan
Features: Turbine centrifugal fan impeller adopts the international standard backward design, the perfect streamline structure, large openings into the center of the impeller inlet wind, the wind through the center port into the wind, resulting in a strong centrifugal force, by the backward tilt fan blades thrown off quickly Turbine structure design makes the wind turbine has a strong wind, wind pressure.
Highlights: Turbine centrifugal fan by the overload thermal motor protection of the outer rotor, high efficiency after the circular arc-shaped centrifugal impeller of two parts. All impeller mold production, high precision dynamic balancing machine calibration, with small size, high efficiency, air volume, small vibration, low noise, superior performance, easy installation and commissioning.
Application: Material: Made of PA6 plastic, plastic one molding process. Diameter size 155mm ~ 250mm.
Applications: Air purification equipment, factory equipment (printing equipment, chemical fiber equipment, etc.), medical equipment, fresh food cabinets, refrigeration cabinets, servo motors, inverters, pipe ventilation, dehumidifiers, etc.
Volute centrifugal fan:
Features: Volute centrifugal fan impeller driven by the motor rotation, the impeller blades forcing gas rotation, the gas to work, to increase its energy, the centrifugal force in the gas around the impeller thrown through the scroll casing will speed Can be converted into pressure energy, when the impeller gas is discharged, the impeller pressure is lower than the pressure inside the inlet, the new gas in the pressure difference under the action of inhalation impeller, the gas is continuously exported from the outlet.
Highlights: The fan is designed with a reasonable impeller angle according to the aerodynamics of air flow. Without any mechanical friction during operation, a reasonable blade shape line minimizes the noise. The optimized impeller minimizes the axial force and has an efficient impeller , And the static and dynamic balance correction, the machine running smoothly, without any damping device, the bearing amplitude is relatively small.
Application: Material: Aluminum die-casting frame, wind wheel made of galvanized sheet, surface black electrophoresis, size Diameter: 120mm ~ 160mm
Applications: Sterilizers, heat exchange systems, clean benches, air shower, laboratory equipment, etc.
choose the suitable fan
1, the first parameter to note are: air volume, total pressure, efficiency, sound pressure level, speed and motor power.
2, Centrifugal fan pressure can be divided into three categories: high pressure centrifugal fan P> 3000Pa, medium pressure centrifugal fan 1000≤P≤3000Pa and low pressure centrifugal fan P <1000Pa. Depending on the stupid physicality and chemical properties of the delivered gas and the use, etc., different types of centrifugal fans are selected.
3, taking into account the loss of air leakage pipeline system, calculation error, as well as the actual fan fan, wind pressure negative deviation, centrifugal fan selection, the general use of air flow rate of 1,05 ~ 1,1, wind pressure of 1,10 ~ 1,15 safety factor. In order to prevent long-term fan in low-efficiency operation, it is not appropriate to use excessive safety factor.
4, in order to make the fan stable operation, should make the fan work in the vicinity of its efficiency, the fan operating point is located in the performance curve of the full pressure peak point on the right (ie, gales side, and is generally located at full pressure peak 80%). Fan design efficiency of the selected conditions, not less than 90% of the fan efficiency.
5, the use of variable frequency fan, the total pressure loss should be calculated as the system rated pressure, but the fan motor power should be calculated on the additional 15% to 20%.
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