Transcript Document
Unit 4. 02 devices with Entrainment tutorial by Elizabeth Kelley Buzbee AAS, RRT-NPS, RCP The lion is upstream from the crane The crane is downstream from The lion The stream of water is flowing from left to right Upstream & downstream are relative terms of location.. It depends in what direction your flow is going & where one [lion] is in relation to the other [crane] The lion is upstream from the crane The crane is downstream from the lion Who is the frog downstream from? Who is the frog upstream from? Now, is the lion upstream or downstream from the frog? Is the frog upstream or downstream from the crane? Is the crane upstream or downstream from the lion? If beavers builds a dam, the water upstream from the dam will back up… there will be increased water pressure upstream From the obstruction. Downstream, the flow may drop down to a trickle • The pressure upstream from an obstruction builds up • The pressure down stream from an obstruction drops off If a beaver builds a dam at point B of the river, what happens to the flow of the water upstream from the beaver’s dam? What happens to the water pressure upstream from the dam? [A] What happens to the water pressure downstream from the dam? [C] A B C • Downstream from the obstruction the speed or the velocity of the gas increases • This increase in velocity will cause the lateral pressure to drop • A suction is created Gas goes into restricted orifice A where the velocity of the gas speeds up. Air C A 02 02 & Air B Air This increased velocity of gas flow creates a vacuum In the area just downstream from the restricted orifice B Downstream from the orifice, the pressure drops Air is pulled into the 02 flow so that there is more flow of air & 02 downstream from the restricted orifice C How the entrainment mask works 02 flow 3 lpm Air A C 02 & Air B Air The entrainment port at B is opened so that 1 lpm of 02 will pull in 6 lpm of air The total flow coming out of C is 3 lpm of 02 + [3 x 6] The total flow rate coming out if C is 21 lpm The Fi02 upstream from A was 100% but the Fi02 downstream From B is lower because air is mixed with the 02.