In Part 1 of this paper, the following basic points concerning the push-pull hoods were investigated both theoretically and experimentally.

1. The close relationship between the push-pull flow in the fluid dynamic situation and the deflected beam in the solid body situation was illustrated and verified.
2. The "cooperation theory on air flow" explains logically the reasons for using push-pull hoods which have convergent types of flow. Using the superposition technique, it can be used to calculate flow deflection and the flow field in the vicinity of push-pull hoods. Many experimental runs verified the agreement between theory and experiment.
3. Push-pull flows are strongly deflected by disturbing side flows near push-pull hoods. The maximum value of deflection occurs at the point where the ratio of the push-pull flow distance x/H is about 0.6 to 0.8. Experimental results for several cases verified this conclusion.