It takes longer than that to produce sperm. What comes out in ejaculation is a mixture of sperm and semen. The sperm is produced in the testes and the semen is produced in the prostrate. Most of what comes out is semen which carries the sperm along. When a healthy guy ejaculates he doesn't let go of all this semen so if he's healthy enough to get another erection he probably can come again in 10 - 20 minutes or so for the 2nd time and longer for the next, etc. However, there'll also be less and less sperm in there because it takes 24 hours for a full recovery of everything. A healthy guy can probably have an orgasm fairly often in a day but the liquid will soon run out... and so will his energy level.