Patent ID: 8429950

Claim:
An olfactometer including: (a) a mixing chamber; (b) a human olfaction interface having a sensing opening to the mixing chamber; (c) a first flow path extending from a sample air inlet to a sample air outlet which is open to the mixing chamber, the first flow path providing a first resistance to flow there through in the direction from the sample air inlet to the mixing chamber; (d) a second flow path extending from a diluent air inlet to a diluent air outlet which is open to the mixing chamber, the second flow path being isolated from the first flow path and including a filter medium therein, the filter medium comprising a length of packed spherical adsorbent particles, the length of packed spherical adsorbent particles defining a filtration path forming part of the second flow path, the second flow path providing a second resistance to flow there through in the direction from the diluent air inlet to the diluent air outlet; (e) a flow indicator arrangement, the flow indicator arrangement for providing a first indication when a flow rate at one or more points in the olfactometer reaches a predetermined value corresponding to a first target dilution ratio of the flow rate through the second flow path to the flow rate through the first flow path in response to a motive force applied at the human olfaction interface; and (f) wherein the second resistance to flow increases at a higher rate than the first resistance to flow in response to the motive force applied at the human olfaction interface so that the dilution ratio of the flow rate through the second flow path to the flow rate through the first flow path gradually decreases to the target dilution ratio in response to the motive force.