Apparatus for indicating how dirty an air filter is in a vacuum-cleaning apparatus, in a room filter, etc.
First Claim
Patent Images
1. An apparatus for indicating how dirty an air filter is that is disposed in an air stream for removing dirt therefrom, comprising:
- an arrangement in the form of a light unit for measuring how dirty said air filter is, said light unit being a forked light unit;
an indicator connected to said light unit;
said filter being a folded filter having folds, each two adjacent ones of which join one another at a common fold edge; and
said forked light unit having two arms that extend over two of said folds and their common fold edge such that a beam of light directed from an emitter of said forked light unit to a receiver thereof passes through said two folds, with a dirt-laden air stream being received on a side of said filter remote from said forked light unit.
1 Assignment
0 Petitions
Accused Products
Abstract
An apparatus is provided for indicating how dirty an air filter is that is disposed in an air stream for removing dirt therefrom. The apparatus includes an arrangement in the form of a light unit for measuring how dirty the air filter is. The apparatus also includes an indicator that is connected to the light unit.
57 Citations
6 Claims
-
1. An apparatus for indicating how dirty an air filter is that is disposed in an air stream for removing dirt therefrom, comprising:
-
an arrangement in the form of a light unit for measuring how dirty said air filter is, said light unit being a forked light unit; an indicator connected to said light unit; said filter being a folded filter having folds, each two adjacent ones of which join one another at a common fold edge; and said forked light unit having two arms that extend over two of said folds and their common fold edge such that a beam of light directed from an emitter of said forked light unit to a receiver thereof passes through said two folds, with a dirt-laden air stream being received on a side of said filter remote from said forked light unit. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification