Purification mechanism of ceramic foam filter

Ceramic Foam filter can effectively intercept inclusions in liquid metal and improve casting quality and yield, ceramic foam filter has four major mechanisms to effectively purify liquid metal.
(1) Floating separation mechanism
After placing the ceramic foam filterin the pouring system, the resistance of liquid metal flow rate increases, and the liquid metal in the pouring system is full of state, so as to play the slag blocking function of the pouring system. At the same time, the liquid flow injected from the straight sprue is throttled through the Filter, the liquid metal stays briefly in the straight sprue, and the slag with small density floats up and separates, which can produce the same effect of the bottom injection pouring system. When the liquid metal passes through the
Ceramic foam filter to continue pouring, on the one hand, the density of small slag floating, on the other hand, effectively reduce or eliminate the eddy current.
(2) "Cake filter" mechanism
Ceramic foam filter is curved channel, can be efficient mechanical slag blocking, many larger than the filter hole in the slag entrapment is captured at the inlet end of the filter. With the increase in the number of captured inclusions, in the filter inlet end of the surface of the formation of large pieces of inclusions generated by the "filter cake". The “cake” makes the liquid flow thin, so that inclusions smaller than the size of the filter are also partially captured in the "cake".
(3) Adsorption mechanism
Filter placed in the cavity of the cross channel or inner sprue, filtration operation is a deep filtration, when the first strand of molten metal arrives at the inlet end surface of the filter, resulting in liquid flow and foam mesh adsorption phenomenon, at the same time, the liquid flow will occur "impact" phenomenon, the filter itself has a blocking effect, some of the impurities in a certain pressure, due to the impurities and the solid foam ceramic mesh. Some inclusions under a certain pressure, due to inclusions and solid foam ceramic mesh frame more similar to the “common grid correspondence” relationship, so that it is easy to lubricate and adsorption, this adsorption is mainly non-selective multi-molecular layer of physical adsorption is the main thing, inclusions in the filter mesh frame adsorption layer by layer, until the blockage.
(4) Rectification effect
When the molten metal flows through the ceramic foam filter, it is divided into many small units of the strand flow, and its diameter is small, so that the Reynolds number (Re=v-D/γ) becomes smaller, so that the liquid flow tends to laminar flow. When the liquid metal is in a laminar flow state, due to the density of molten metal is much greater than the density of inclusions, so that inclusions have sufficient time to float to remove, so the ceramic foam filter can also assist in the cross-cast channel slag blocking, pouring system after placing the filter, the liquid metal flow resistance increases, in the cross-cast channel in the flow of the liquid metal is easy to form a full flow, and make the flow rate lower, conducive to the floating of inclusions and retained in the The top surface of the cross-cast channel.