Mai sanyaya ruwa na masana'antu nau'in kayan aikin sanyaya ruwa ne wanda zai iya samar da zafin jiki akai-akai, daɗaɗɗen halin yanzu, da matsa lamba. Ka'idarsa ita ce allurar wani adadin ruwa a cikin tanki kuma sanyaya ruwan ta hanyar tsarin sanyi nachiller, to, famfo na ruwa zai canza ruwan sanyi mai ƙananan zafin jiki zuwa kayan aiki don sanyaya, kuma ruwan zai dauke zafi a cikin kayan aiki, kuma ya koma cikin tanki na ruwa don sake sanyaya. Ana iya daidaita zafin ruwan sanyi kamar yadda ake buƙata.