valupea, mille konstruktsioon tagab valandi toitmise sulametalliga atmosfäärirõhul; sellel otstarbel kasutatakse ventilatsioonikärni (vt valupea, ventilatsioonikärn; vrd ülerõhkvalupea), a riser that uses atmospheric pressure to aid feeding, essentially a blind riser into which a small core (atmospheric core) or rod protrudes; the function of the core or rod is to provide an open passage so that the molten interior of the riser will not be under a partial vacuum when metal is withdrawn to feed the casting but will always be under atmospheric pressure (see: riser, atmospheric core; compare: pressure head)