摘要 |
<p>The supply of a reagent to a mixing chamber is controlled by apparatus comprising a housing 1 having an inlet for the reactant, an outlet 4 to the mixing chamer 5, an inlet 3 for a flushing medium, an outlet 6 for recirculating the reactant and, within the housing, a movable member 7 having first and second ducts 10 and 12, duct 10 connecting inlet 2 with either of outlets 4 and 6 independently, and duct 12 connecting inlet 3 with outlet 4 when inlet 2 and outlet 6 are connected, inlet 3 being blocked when inlet 2 and outlet 4 are connected.</p> |