Claims
- 1. A filter medium for an oil filter or an air filter for an internal combustion engine to remove dust particles from a fluid to be filtered; said filter medium comprising a nonwoven fabric of a lower fiber density which comprises at least two layers, and a filter paper of a higher fiber density, said nonwoven fabric and said filter paper being superposed in a laminated structure, one of said layers of the nonwoven fabric, which is closer to said filter paper, having a fiber density lower than that of the other of said layers of the nonwoven fabric which is located opposite to said filter paper with respect to the one of said layers, the one of said layers being a thermally fusible layer, said nonwoven fabric and said filter paper being joined together through the thermally fusible layer of the nonwoven fabric.
- 2. A filter medium according to claim 1, wherein the other of said layers has a fiber density of 0.15 to 0.25 g/cm.sup.3, while the one of said layers has a fiber density of 0.1 to 0.2 g/cm.sup.3 and said filter paper has a relatively high fiber density of 0.2 to 0.3 g/cm.sup.3.
- 3. A filter which has a filter medium for an oil filter or an air filter for an internal combustion engine to remove dust particles from a fluid to be filtered; said filter medium comprising a nonwoven fabric of a lower fiber density which comprises at least two layers, and a filter paper of a higher fiber density, said nonwoven fabric and said filter paper being superposed in a laminated structure, one of said layers of the nonwoven fabric, which is closer to said filter paper, having a fiber density lower than that of the other of said layers of the nonwoven fabric which is located opposite to said filter paper with respect to the one of said layers, the one of said layers being a thermally fusible layer, said nonwoven fabric and said filter paper being joined together through the thermally fusible layer of the nonwoven fabric, said filter medium being arranged such that said nonwoven fabric and said filter paper are disposed upstream and downstream, respectively, in a direction in which said fluid to be filtered flows.
- 4. A filter according to claim 3, wherein the other of said layers has a fiber density of 0.15 to 0.25 g/cm.sup.3, while the one of said layers has a fiber density of 0.1 to 0.2 g/cm.sup.3 and said filter paper has a relatively high fiber density of 0.2 to 0.3 g/cm.sup.3.
Priority Claims (2)
Number |
Date |
Country |
Kind |
62-199918 |
Aug 1987 |
JPX |
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62-199919 |
Aug 1987 |
JPX |
|
Parent Case Info
This is a continuation of application No. 07/230,555 filed Aug. 10, 1988, now abandoned.
US Referenced Citations (19)
Continuations (1)
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Number |
Date |
Country |
Parent |
230555 |
Aug 1988 |
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