Hatches & Toothed motor Hatches executed in plywood with coating. Inlet hatches incorporated in the wall. Inlet hatch “Trespa”. Outlet hatches in the ridge of the barn. Outlet hatches in the ridge. Extension for extraction of air. Extension for extraction/evacuation of air. Inlet /outlet hatch with rubber in frame in details. Detail of inlet/outlet hatch. Practical situation with mixing hatch. Practical situation with mixing hatch. Practical situation with mixing hatch. Practical situation for external circulation. Valve open for internal circulation. Air mixing unit with mix-hatches for inside/mix/outside air. Practical situation hatches; air mixing 50/50%. Air intake and discharge hatshes above each other.. Aspiration structure with outlet hatch. Info hatch position: 79% open. Setup page hatches. Status page hatches. Toothed motor for opening hatches. Detail of pinion and rack. Detail of rack with window clamp. Bearing sheet with ball bearings. Bearing sheet for ax. Angle bevel gear axes.