'Ralph' and 'Ralf' can be interchangable. The origin of 'Ralph' comes from the sound one makes when they throw up, "RRRAAAAAALLLLPH!!"
"If I keep drinking at this pace, I'm gonna meet Raplh."
"Hey did you hear? Bill met Ralph last night."
"If you want me to drink all those forties, I'm gonna have to introduce you to Ralph."