Sand casting method for closed impeller of low specific speed centrifugal pump

Abstract

The invention relates to a sand casting method for a closed impeller of a low specific speed centrifugal pump. The sand casting mold used includes a lower mold, a lower sand box, an upper mold, a middle sand box, an upper sand box, a runner, a sprue, and a straight runner. The gate, inner runner, locating pin sleeve, locating pin, and impeller cavity are cast using the above-mentioned sand casting mold. After molding and placing the mud core, when pouring, the molten iron flows vertically from the sprue 7 and passes through the horizontal horizontal The sprue and the vertical sprue on the upper mold, and then flow into the two cavities from the inrunners separated horizontally on both sides. Compared with before, the sprue and runner are added, and the path of molten iron inflow is increased, which can slow down the inflow speed of molten iron and prolong the inflow time of molten iron, so that the gas in the impeller cavity can be discharged in time, and the molten iron flows into the gas The vented cavity can effectively solve the foaming phenomenon of castings, and the quality is stable.

Description

technical field [0001] The invention relates to a sand casting method for a centrifugal pump impeller, in particular to a sand casting method for a closed impeller of a low specific speed centrifugal pump. Background technique [0002] With the improvement of energy saving, environmental protection and safety requirements, more and more centrifugal pumps with small flow rate and high head and low specific speed are used. The impellers of this type of centrifugal pump are generally made of cast iron, with a closed structure and an upper cover and a lower cover. The middle is the water outlet channel, and the modeling adopts clay sand technology, aluminum alloy mould, two boxes of wooden sand boxes, and the lower resin sand or coated sand mud core. Due to the upper cover plate and the lower cover plate, the resin sand or coated sand mud core forming the blade should be placed during molding. In this way, the air in the cavity is not discharged smoothly during pouring, and it ...

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Problems solved by technology

[0004] The present invention aims at the situation that the molten iron inflow path is relatively close due to the molding of the two boxes, the inflow speed is relatively fast, the time for inflow into the cavity is short, and the gas in the cavity cannot be discharged in time and effectively during the pouring after the above molding, and provides a The low specific speed centrifugal pump closed impeller sand casting method abandons the traditional thinking of finding how to exhaust air as soon as possible, and creatively proposes to extend the path of molten iron inflow, so that the gas in the cavity has time to discharge

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