Stainless Steel Gear pump two common failures

1. Trapped oil phenomenon (tooth seal phenomenon)

(1) What is the phenomenon of trapped oil?

In order to make stainless steel gear pump run continuously, and the overlap coefficient of the gear is greater than 1, that is, there are two pairs of gears engaged at the same time, and a closed space is formed between them and the end cover. The space decreases from large to small, and the minimum is the meshing point is symmetric to the node, and then the space increases from small to large.

(2) The harm of trapped oil phenomenon

When the closed volume decreases, the pressure in the closed volume increases sharply, so that the bearing is subjected to a great additional load, and at the same time, power loss and liquid heating and other adverse phenomena;

When the closed volume increases, the pressure in the closed volume drops sharply, and the air dissolved in the liquid precipitates to produce bubbles, resulting in cavitation phenomenon, causing vibration and noise.
(3) Measures to eliminate trapped oil

A) Reduce the size of oil pressure port;
B) Open unloading groove: symmetrical unloading groove, asymmetric unloading groove and special shape unloading trough
(2) Methods to eliminate the unbalanced radial force

A. Pressure balance groove - the high pressure liquid is introduced into the low pressure teeth, and the low pressure liquid is introduced into the high pressure teeth;
B. Reduce the discharge of the mouth, so that the bearing surface of the gear is reduced, only acting on 1 or 2 teeth.

2. internal leakage gear pump internal leakage mainly has three positions

(a) axial clearance - between the end face of the gear and the pump front and rear cover (or sleeve), the leakage accounts for about 70 ~ 80% of the total leakage;
(b) radial clearance -- the fan-shaped arc surface between the top circle and the pump body hole, accounting for about 10 ~ 15% of the total internal leakage;
(c) the engagement of two gears.