GNF pump belongs to the positive displacement pump, and its main working components are the eccentric spiral screw (referred to as rotor) and the screw liner (referred to as stator) with a double helix surface on the inner surface. Its working principle is that when the motor drives the pump shaft to rotate, the screw rotates around its own axis on one hand, and on the other hand, it rolls along the inner surface of the liner, thus forming a sealed chamber of the pump. Every time the screw rotates, the liquid in the sealed chamber advances one pitch forward. With the continuous rotation of the screw, the liquid is pressed from one sealed chamber to another in a spiral manner, and finally squeezed out of the pump body.