Hemodialyzer is abbreviated as dialyzer, which is a pipe and container for solute exchange between blood and dialysate, and is a key part of hemodialysis. The dialyzer provides controllable transfer of solutes and water across the semipermeable membrane. The flows of dialysate and blood are separated and countercurrent. The dialyzer has four ports, one inlet and one outlet port respectively for blood and dialysate.