40HP Robinson Air Ring blower

40HP Robinson Air Ring blower type RL s/n 7519-L size 50-20 drawing # ML-50-20-2-0 WZ-AA-44586007-XX stock # 4515-007 Inlet flange has a damper, minus the plate, mounted on it. OD of 20”, ID of 17”. It has 12 holes of ½”, arrayed at 18-3/4”. Blower flange inlet ID of 14”. Outlet flange 21”/14” with 12 holes of 1” ID arrayed in a diameter of 18-3/4 “.