Hemodialysis Machine is the equipment used to purify the blood of a person whose kidneys are not working properly. A pump in the hemodialysis machine slowly draws out the blood, then sends it through another machine called a dialyzer. This work like a kidney and filters out extra salt, waste, and fluid. The clean blood is sent back into the body through the second needle in the arm. In hemodialysis, the entire blood is circulated outside the body in a machine placed outside the body known as a dialyzer.