The design of the pouring system is introduced by taking a combined hydraulic valve body as an example. The closed intermediate injection pouring system is used. The number of inner runners in the pouring system is 1. The cross-sectional area ratio of inner, cross and straight runners is Ag:Aru:As=1:1.2:1.5. The minimum cross-sectional area of inner runner is calculated by Ozan’s formula:
M – the weight of the liquid metal flowing through the inner flow channel (kg);
Rho – density of metal liquid (kg/cm3);
T – filling time (s);
G – Gravity acceleration;
ψ – Flow loss coefficient of pouring system;
Hp – Average static head height (cm).
The casting material is ductile iron QT500-7, the density of liquid metal is 7×10-3kg/cm3, and the weight of liquid metal flowing through the inner flow channel is 8.4kg.