Later, with the continuous advancement of science and technology, the technical content of the intermittent pre-expansion machine is also continuously improved, and new models continue to appear thereupon, forming various technical systems.
my country had already begun to use the intermittent pre-expansion machine as early as the 1950s, but it was not a special intermittent pre-expansion machine, but an improvement by using a mortar mixer. That is to say, the foaming agent is directly added to the mortar mixer or the semi-automatic foam molding machine concrete mixer, and the foaming agent and the mortar or concrete are stirred together to form foam. It was not until around the 1970s that a special foaming machine began to appear in our country, that is, a high-speed impeller intermittent pre-expansion machine. After continuous technical upgrading and replacement, now there is a third-generation intermittent pre-foaming machine model with high-pressure inflation as the main body, which can basically meet the needs of foam concrete.
There are many brands and models of intermittent pre-foaming machines, but based on the basic foaming principle, there are only three types that are widely used at present: high-pressure air type, high-speed impeller type, and blast medium-low pressure type. The difference of the same type of batch pre-foaming machine is only the difference in its auxiliary equipment and automatic control equipment, and the structure of the foaming part is basically the same.