초록 ▼

A multilayer filter pack includes at least three adjacent layers of fibrous material, each of which is permanently electrically charged and not more than 10 mm thick. The upstream and middle layers are formed from fibers having a fiber diameter that decreases from layer to layer in the direction of

A multilayer filter pack includes at least three adjacent layers of fibrous material, each of which is permanently electrically charged and not more than 10 mm thick. The upstream and middle layers are formed from fibers having a fiber diameter that decreases from layer to layer in the direction of flow and are arranged at a packing density that increases from layer to layer in the direction of flow. The third layer has a fiber diameter and packing density that is approximately equal to the fiber diameter and packing density of the first layer. The multilayer filter pack is particularly well suited for use in air-purifying systems and breath protection filters.

대표청구항 ▼

A multilayer filter pack comprising at least first, second and third adjacent layers of fibrous electret material formed from fibers having a predetermined fiber diameter arranged in each layer at a predetermined packing density with each layer having a permanent electric charge and a thickness grea

A multilayer filter pack comprising at least first, second and third adjacent layers of fibrous electret material formed from fibers having a predetermined fiber diameter arranged in each layer at a predetermined packing density with each layer having a permanent electric charge and a thickness greater than twice the predetermined fiber diameter of its respective layer and less than 10 mm wherein said first layer is disposed in a position upstream of the second layer and is formed from fibers having a fiber diameter in the range of 10 to 30 um arranged at a packing density in the range of 0.01 to 0.07, said second layer is formed from fibers having a fiber diameter in the range of 0.5 to 10 um arranged at a packing density in the range of 0.03 to 0.1., said third layer is disposed in a position downstream of said second layer and is formed from fibers having a fiber diameter approximately equal to the fiber diameter of the first layer arranged at a packing density approximately equal to the packing density of the first layer and the fiber diameter of said first and second layers decreases from the first layer to the second layer in the direction of flow and the packing density of said first and second layers increases from the first layer to the second layer in the direction of the flow wherein more than 50% of particles of a medium to be filtered having a grain size in the range of 10 to about 0.5 um are filtered by the first layer.