Recently, the weather is cold, will the cold air have any influence on LED products ?
Under normal circumstances, in addition to the normal temperature change, the temperature of the LED guardrail tube changes in addition to the normal temperature change, and the greenhouse effect caused by the warming of the sunlight. What effect does the temperature have on the guardrail tube? The equation of state of the gas is used below for analytical calculations. A certain amount of gas state is generally described by three parameters: volume, temperature, and pressure. The relationship between them has the following equation of state:
pV=nRT
Where n - the molar amount of gas, its three state quantities: p - pressure (unit KPa, kilopascal), V - volume, T - gas thermodynamic temperature (unit K, Kelvin, equal to 273.15 + Celsius); R ―Gas constant (R is related to pressure, temperature, gas type, and the guardrail tube can be considered as a fixed value in the normal application environment).
Under normal circumstances, when a guardrail tube is completed, the molar amount n of the gas sealed in the tube is fixed, and the volume V is constant, and the temperature T changes, thereby causing the pressure P to follow the change. The relationship between state quantities is expressed by the following mathematical formula:
Where p1 is the gas pressure at the time of tube encapsulation, generally the standard atmospheric pressure is 101.325 kPa. T1 is the temperature at which the guardrail tube is packaged. With the change of production time, the temperature is T2 when installed outdoors with temperature change, and P2 is the gas pressure which varies with T2. After simplification, it becomes: P1=P1*T2/T1:
If the standard atmospheric pressure and temperature are 25 °C during packaging, then T1=273+25=298K, p1=101.325KPa, and when the temperature rises to 45°C, T2=273+45=318K, substituting into the above formula 3 can be obtained:
P2=101.325KPa×318K/298K=108.125KPa
At this time, the internal pressure of the lamp is increased by p2-p1=6.8KPa, the typical LED guardrail tube D-section is 50*50mm, and the inner surface area of ​​the length of 1m is about 0.17 square meters. The pressure of the inner wall of the pipe is 6.8KPa×0.17 square. Meter = 1156 Newtons, about 118 kilograms of force.
When the temperature drops to 17 degrees at night: T2 = 273 + 17 = 290. After the same calculation, the gas pressure in the tube is 98.6 KPa, the negative pressure generated at atmospheric pressure is 2.725 KPa, and the reverse pressure generated is 463.25 Newtons. 47 kg force.
Through the above calculations, we can see that the guardrail tube is affected by the large or small force every day, destroying the sealing structure. If the temperature is lowered at this time, the negative pressure inside the guardrail tube will inhale into the interior of the lamp, and the moisture attached to the outer casing will be The gap is entered (the large cooling process is usually accompanied by rain and snow).
The above is just an analysis of the D50 type tube. The actual LED lighting night view project has a larger tube, and the temperature change in the actual environment is also more severe. This can understand the reason that some guardrail tubes will break. Manufacturers of LED guardrail tubes rarely face the impact of the climate, and without exception, they have made new innovations in the sealing process. Pay attention to balance the internal and external air pressure of the LED guardrail tube, eliminate the damage factor brought by the temperature change to the guardrail tube, avoid the cooling and low pressure water absorption, and try to reduce the adverse effect of temperature on the LED guardrail tube.
Fiber Media Converter,Fiber Media Converter Switch,fiber media converter,Fiber Media Converter
Fiber Media Converter,Passive POE Switch Co., Ltd. , http://www.nbpoeswitch.com