| 主权项 |
1. A framed air filter comprising:
a filter media with an upstream side and a downstream side and a perimeter, wherein the filter media comprises:
a microperforated film comprising a first, upstream face and a second, downstream face and comprising a plurality of tapered microperforations extending through the microperforated film from the first, upstream face to the second, downstream face,
wherein the tapered microperforations comprise a wide end at the first, upstream face of the microperforated film and a narrow end at the second, downstream face of the microperforated film, wherein the narrow ends of the tapered microperforations exhibit a diameter of from about 150 microns to about 400 microns, and wherein the wide ends of the tapered microperforations collectively provide the first, upstream face of the microperforated film with a % open area of from about 50% to about 95%;and,a nonwoven filtration web positioned on the first, upstream face of the microperforated film with a first, downstream face of the nonwoven web in contact with the first, upstream face of the microperforated film and with the nonwoven filtration web being thermally point-bonded to the first, upstream face of the microperforated film, at an area bond that is less than about 5%,
wherein the nonwoven web exhibits an area coverage of from about 20% to about 50%, wherein the nonwoven web exhibits a solidity of from about 1% to about 4%, wherein the nonwoven web exhibits an area density of from about 10 grams per square meter to about 50 grams per square meter, and wherein the nonwoven web exhibits an average fiber diameter of from about 30 microns to about 200 microns, and, a support frame surrounding the perimeter of the filter media. |
