US4011067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter medium layered between supporting layers
Assignee: 3M Co
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Filing: 1975-09-11
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Granted: 1977-03-08
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Expires: 1995-09-11
Abstract
Abstract A new filter medium, which can remove a high percentage of fine particles from a gas stream while causing a relatively low pressure drop in the gas stream, comprises a base porous web, one or more lightweight non-self-supporting layers of microfibers collected and carried on the base porous web, and a top porous web. A new aerosol filter apparatus incorporates the new filter medium to provide economical consistent filtering of air in a home, office, or industrial environment. In this new filter apparatus, a web of the filter medium extends from a supply roll across a stream of the air being cleaned to a take-up roll; and the filter medium is advanced from the supply roll to the take-up roll to gradually provide a fresh length of filter medium in the air stream.
Inventors
- 👤 Patrick H. Carey, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:43
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; Y; Y10; Y10S; Y10S55/00; Y10S55/35
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
164 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed handleable self-supporting porous fibrous base layer; at least one thin lightweight non-self-supporting filtration layer of randomly arranged microfibers having an average diameter less than about 0.5 micrometer collected on said base layer by interposing the base layer in a stream of the microfibers, said layer of microfibers weighing less than about 0.01 pound per square yard; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material; said base and top layers contributing less than 20 percent of the pressure drop through the filter medium at a face velocity of 100 feet per minute; and said layer of microfibers having a relationship of initial particle penetration to pressure drop when tested at a face velocity of 100 feet per minute within the range defined by curves C and D shown in FIG. 3.
Claim 2
Dependent Claim
164 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed handleable self-supporting porous fibrous base layer; at least one thin lightweight non-self-supporting filtration layer of randomly arranged microfibers having an average diameter less than about 0.5 micrometer collected on said base layer by interposing the base layer in a stream of the microfibers, said layer of microfibers weighing less than about 0.01 pound per square yard; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material; said base and top layers contributing less than 20 percent of the pressure drop through the filter medium at a face velocity of 100 feet per minute; and said layer of microfibers having a relationship of initial particle penetration to pressure drop when tested at a face velocity of 100 feet per minute within the range defined by curves C and D shown in FIG. 3.
Claim 3
Dependent Claim
21 words
A filter medium of claim 1 in which the layer of microfibers weighs less than about 0.01 pound per square yard.
Claim 4
Dependent Claim
28 words
A filter medium of claim 1 which exhibits a pressure drop of less than about 0.5 inch of water at a face velocity of 100 feet per minute.
Claim 5
Dependent Claim
28 words
A filter medium of claim 1 that exhibits a pressure drop of about 3 to 4 inches of water at a face velocity of 50 feet per minute.
Claim 6
Dependent Claim
28 words
A filter medium of claim 1 that exhibits a pressure drop of about 0.3 to 0.5 inch of water at a face velocity of 15 feet per minute.
Claim 7
Dependent Claim
72 words
An aerosol filter apparatus comprising a) blower means for drawing the aerosol through an inlet, moving the aerosol along a path, and then exhausting; the aerosol through an outlet, b) a filter medium of claim 1 stored in a replaceable supply roll and extending across said path to a take-up roll, and c) drive means for advancing the filter medium at a predetermined rate from the supply roll to the take-up roll.
Claim 8
Dependent Claim
28 words
A respirator adapted to be worn by a person, in which a filter medium of claim 1 is disposed across the path of air intake into the respirator.
Claim 9
Dependent Claim
17 words
A filter medium of claim 1 in which the microfibers comprise a polymer based on vinyl chloride.
Claim 10
Dependent Claim
42 words
A room air cleaner comprising a) blower means for drawing air through an inlet, moving the air along an air path, and then exhausting the air through an outlet, and b) a filter medium of claim 1 disposed across the air path.
Claim 11
Dependent Claim
53 words
A room air cleaner of claim 6 in which the filter medium is stored in a supply roll and extends across the air path to a take-up roll, and the room air cleaner includes drive means for advancing the filter medium at a predetermined rate from the supply roll to the take-up roll.
Claim 12
Dependent Claim
15 words
A filter medium of claim 1 in which the layer of microfibers comprises solution-blown microfibers.
Claim 13
Dependent Claim
26 words
A filter medium of claim 9 in which the layer of microfibers includes rounded nonfibrous particles of the polymer from which the solution-blown microfibers are made.
Claim 14
Dependent Claim
19 words
A filter medium of claim 11 in which the microfibers have an average diameter less than about 0.3 micrometer.
Claim 15
Dependent Claim
116 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed handleable self-supporting porous fibrous base layer; at least one thin lightweight filtration layer of solution-blown polymeric randomly arranged microfibers having an average diameter less than about 0.5 micrometer deposited on said base layer, said layer of microfibers weighing less than 0.01 pound per square yard; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material; said base and top layers contributing less than 20 percent of the pressure drop through the filter medium when tested at a face velocity of 100 feet per minute.
Claim 16
Dependent Claim
116 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed handleable self-supporting porous fibrous base layer; at least one thin lightweight filtration layer of solution-blown polymeric randomly arranged microfibers having an average diameter less than about 0.5 micrometer deposited on said base layer, said layer of microfibers weighing less than 0.01 pound per square yard; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material; said base and top layers contributing less than 20 percent of the pressure drop through the filter medium when tested at a face velocity of 100 feet per minute.
Claim 17
Dependent Claim
27 words
A filter medium of claim 14 in which the layer of solution-blown microfibers includes rounded nonfibrous particles of the polymer from which the solution-blown microfibers are made.
Claim 18
Dependent Claim
19 words
A filter medium of claim 14 in which the microfibers have an average diameter of less than 0.3 micrometer.
Claim 19
Dependent Claim
47 words
A filter medium of claim 14 in which said layer of microfibers has a relationship of initial particle penetration to pressure drop when tested at a face velocity of 100 feet per mintue within the range defined by the curves C and D shown in FIG. 3.
Claim 20
Dependent Claim
28 words
A respirator adapted to be worn by a person in which a filter medium of claim 14 is disposed across the path of air intake into the respirator.
Claim 21
Dependent Claim
21 words
A filter medium of claim 14 in which said layer of microfibers weighs less than about 0.005 pound per square yard.
Claim 22
Dependent Claim
132 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed porous nonwoven fibrous base layer; at least one thin lightweight filtration layer of solution-blown polymeric randomly arranged microfibers having an average diameter less than about 0.5 micrometer deposited on said base layer, said layer of microfibers weighing less than 0.01 pound per square yard and having insufficient integrity to be removed form the base layer and wound and unwound by itself from a storage roll, but contributing at least 80 percent of the pressure drop through the filter medium when measured at a face velocity of 100 feet per minute; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material.
Claim 23
Dependent Claim
132 words
A multilayer filter medium exhibiting a low pressure drop at a desired particle penetration comprising a preformed porous nonwoven fibrous base layer; at least one thin lightweight filtration layer of solution-blown polymeric randomly arranged microfibers having an average diameter less than about 0.5 micrometer deposited on said base layer, said layer of microfibers weighing less than 0.01 pound per square yard and having insufficient integrity to be removed form the base layer and wound and unwound by itself from a storage roll, but contributing at least 80 percent of the pressure drop through the filter medium when measured at a face velocity of 100 feet per minute; and a porous top layer laminated over the layer of microfibers so as to unify the filter medium into a single handleable self-supporting sheet material.
Claim 24
Dependent Claim
46 words
A filter medium of claim 20 in which said layer of microfibers has a relationship of initial particle penetration to pressure drop when tested at a face velocity of 100 feet per minute within the range defined by curves C and D shown in FIG. 3.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-07 | 1980-09-06 | 1981-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-07 | 1984-09-06 | 1985-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-07 | 1988-09-06 | 1989-03-08 | $7700.00 | Window Closed / Lapsed |