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What is the working principle of an explosion-proof valve?
Release time:2022-12-06
The PUW explosion-proof valve uses an imported expanded polytetrafluoroethylene (E-PTFE) microporous membrane as its primary waterproof and breathable material. The micropores of this imported E-PTFE membrane have diameters ranging from 0.1 to 10 μm, whereas the average diameter of air molecules is only 0.00036 μm, and that of water vapor is approximately 0.00047 μm. Meanwhile, the diameter of drizzle droplets is around 500 μm. Thus, the pore size of the E-PTFE membrane is more than 1,000 times larger than the diameter of gas molecules and thousands of times smaller than that of water droplets. Additionally, due to the extremely low surface energy of the E-PTFE membrane, under the effect of surface tension—where water molecules pull on each other—small water droplets quickly coalesce into larger beads on the surface of the E-PTFE membrane. As a result, gases can pass through smoothly, while liquid water cannot, giving the membrane excellent waterproof and breathable performance.
When the internal pressure inside the battery pack enclosure is lower than the burst pressure setting of the explosion-proof valve, the valve operates in its normal working state (as shown in the right diagram). In this operating state, the valve functions similarly to conventional waterproof and breathable valves: gases inside and outside the cavity freely flow through the built-in E-PTFE waterproof and breathable membrane. Gas flows from the area of higher pressure to the area of lower pressure—meaning that when the internal pressure exceeds the external pressure, gas is released outward; conversely, when the internal pressure falls below the external pressure, gas enters the cavity, thereby achieving pressure equilibrium between the inside and outside. Under these conditions, the PUW explosion-proof valve acts as a waterproof and breathable valve (breathing valve).
When the internal pressure inside the cavity reaches or exceeds the burst pressure setting of the explosion-proof valve, the valve enters its explosion-proof working state (as shown in the right diagram). At this point, the internal pressure pushes open the built-in piston, allowing gas to flow directly to the outside through an unobstructed channel, rapidly releasing the gas and swiftly reducing the internal pressure, thus preventing the cavity from bursting. In this state, the valve serves its explosion-proof function.
Once the internal pressure drops below the burst pressure setting of the explosion-proof valve, the PUW explosion-proof valve immediately returns to its normal working state. Therefore, the PUW explosion-proof valve is not a single-use product; it undergoes 100% inspection both before shipment and during use to ensure that its explosion-proof functionality meets the required standards.
The PUW explosion-proof valve uses an imported expanded polytetrafluoroethylene (E-PTFE) microporous membrane as its primary waterproof and breathable material. The micropores in this imported E-PTFE membrane have diameters ranging from 0.1 to 10 μm. In contrast, the average diameter of an air molecule is only 0.00036 μm, while the average diameter of a water vapor molecule is 0.00047 μm. By comparison, the diameter of drizzle droplets is around 500 μm. Thus, the pore size of the E-PTFE membrane is more than 1,000 times larger than the diameter of gas molecules—and thousands of times smaller than that of water droplets. Moreover, due to the extremely low surface energy of the E-PTFE membrane, under the influence of surface tension (where water molecules pull on each other), small water droplets quickly coalesce into larger beads on the membrane’s surface. As a result, gases can pass through smoothly, while liquid water cannot, giving the membrane excellent waterproof and breathable performance.
When the internal pressure inside the battery pack enclosure is lower than the burst pressure set for the explosion-proof valve, the system is in a normal operating state (as shown in the right figure). In this operating state, the valve functions in the same way as a conventional waterproof and breathable valve: gases inside and outside the cavity freely flow through the E-PTFE waterproof and breathable membrane built into the valve. Gas flows from the side with higher pressure to the side with lower pressure—meaning that when the internal pressure of the cavity exceeds the external pressure, gas is vented outward; conversely, when the internal pressure is lower than the external pressure, gas enters the cavity, thereby achieving pressure equilibrium between the inside and outside. Under these conditions, the PUW explosion-proof valve acts as a waterproof and breathable valve (breathing valve).
When the internal pressure inside the cavity exceeds or equals the burst pressure setting of the explosion-proof valve, the system enters an explosion-proof operating state (as shown in the right diagram). At this point, the internal pressure pushes open the built-in piston, allowing gas to flow directly through an unobstructed passage to the outside, thereby rapidly venting the gas and quickly reducing the internal pressure, thus preventing the cavity from bursting. In this state, the system effectively serves as an explosion-proof device.
When the internal pressure drops below the rupture value set for the explosion-proof valve, the PUW explosion-proof valve will immediately return to its normal operating state. Therefore, the PUW explosion-proof valve is not a single-use product and can be 100% inspected both before shipment and during use to ensure that its explosion-proof function meets the required standards.
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