data.raw["recipe"]["pipe-elbow"   ].hidden = true;
data.raw["recipe"]["pipe-junction"].hidden = true;
data.raw["recipe"]["pipe-straight"].hidden = true;

data.raw["item"]["pipe-elbow"   ].hidden = true;
data.raw["item"]["pipe-junction"].hidden = true;
data.raw["item"]["pipe-straight"].hidden = true;

for newer versions of the game, use this one: https://mods.factorio.com/mod/Flow_Control_Valves_Only