ʻO ka Cast Iron Dual Plate Check Valve kahi ʻano o ka valve nānā i hoʻolālā ʻia e ʻae i ke kahe (ʻo ka wai a i ʻole ke kinoea) e kahe i hoʻokahi ala wale nō a pale i ke kahe hope. ʻO ka "dual plate" e pili ana i ka ʻano hana kūloko o ka valve, nona nā papa hinged ʻelua e wehe ana e ʻae i ke kahe o ka wai a pani e pale i ke kahe hope. Ma ke ʻano he valve nānā, ʻo kāna hana nui ka pale ʻana i ke kahe hope. Wehe nā papa ʻelua i ka wā e holo ai ke kahe ma ke ala i manaʻo ʻia, a pani koke lākou i ka wā e hoʻohuli ai ke kahe, e pale ana i ke kahe hope a i ʻole ka siphoning.