What is lamp respirator and how it work?
Jan 14, 2019


Respirator's importance on outdoor lamps



    Principle and function of respirator


    Respirator is a sealed component by combining ePTFE film injection molding,ultrasonic welding and other processes.As shown in Figure 1:


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    Its principle is to continuously balance the internal pressure of the shell, and then prevent the positive pressure and vacuum caused by the pressure accumulation of the shell, as shown in Figure 2:



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    Outdoor lamps are frequently confronted with the effects of rainwater, fog,ice and snow, wind and sand, as well as the alternating changes of day and night temperature.Therefore, for temperature sensitive outdoor products, it is particularly necessary to be able to adapt to various weather changes.This kind of problem has been troubling engineers. After realizing the problem, they have adopted various design schemes to achieve reliable protection for LED lights, street lights, spotlights, tunnel lights, line lights, stage lights, landscape lights, decorative lights, industrial and mining lights, alarm lights and so on. However,they are still unable to overcome the inconsistency of internal and external pressure, water vapor, fogging and other phenomena on the lamp surface.


    After years of lighting applications, respirators are proved to be more durable than competing products. They can keep the best performance in the severe environment all the time! 


    1.Respirators help the outdoor lamps more durable and prevent them from oil,water,dust and other pollution.


    2.Respirators can reduce shell stress for the applied seals,prolonging the lifetime of outdoor lamps.


    3.Air permeable products can be installed manually or automatically,which is easily and can reduce maintenance costs.


    Respirators’ application in lamps


    Principle of pressure difference between inside and outside of lamps fixtures


    We can take the interior of the lamp as a fixed size cavity.According to the gas equation of state,PV=nRT(P is unit of pressure Pa,V is cavity volume m³,n is amount of substance of gas,T is thermodynamic temperature,R is ideal gas constant).Assume the lamp is sealed and ambient temperature is T0,when the lamp is not electrified,then P0=nR(273+T0)/V,V/nR=(273+T0)/P0.


    When the lamp is working,the temperature inside the cavity increases to T1.For the sealed cavity,V and n will not change with temperature.Then pressure is P1=nR(273+T1)/V. Then the pressure difference between inside and outside of lamps fixtures is DP=P1-P0=(T1-T0)*nR/V=(T1-T0)*P0(273+P0);

P0=105Pa,R=8,134(Pa/m3),assume the ambient temperature is T0=25℃,then DP=(T1-25)/298(bar).

When the temperature of the lamp increases to 70℃, DP=0.151bar, it means that the lamp will bear the equivalent pressure of 1.5m water column.At this time,the respirators act as a balance between internal and external pressure differences.


    At present,there are plastic, stainless steel, aluminium alloy, copper and so on in the market of lamp respirators. Puwei plastic respirator whose specification is m12/m6, is one of the most widely used in outdoor lamps and lanterns.Though plastic respirator is cheap,if the material of it is good,it can be used for at least 8 years lifspan.The lifespan of metal respirator is long enough to reach 15 years or longer.Secondly,we should think about the ability of waterproof and permeable of the diaphragm inside lamp respirator.The protection grade of ordinary diaphragm is IP65~IP68.According to the requirements of lamp fixtures,we just need to choose the corresponding protection grade of the respirators.Waterproof grade and air permeability of lamp respirators need to be tested by professional measuring instruments.




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