"Ces résultats seraient dûs demain." -- These results would be due tomorrow.
This is conditional present tense. The past participle of "devoir" is actually used as an adjective here. You could replace it with another adjective such as "jaune" (even though that doesn't make a whole lot of sense):
Ces résultats seraient jaunes demain. -- These results would be yellow tomorrow.
The use of the infinitive actually parallels its use in English in this case:
Il devrait partir. -- He would have to leave. (also: he should leave.)
"Partir"is the infinitive in French and "to leave" is the infinitive in English. So the constructions are very similar in this case.
-- Chris (not a native speaker).