Control of the extrusion speed of mud flow at each point of the mud section

07-22

When producing porous bricks and hollow bricks, it is also necessary to check whether the hardness of each part of the extruded mud strip is consistent.
When the screw reamer of the extruder extrudes the mud material, the extrusion speed of the mud material in the middle and the mud material at the edge are different. It is common that the mud material in the middle is much faster than the mud material at the edge. On the extruded whole mud strip, the mud material in the part with the fast mud flow speed is dense, the water content is less, the shrinkage of drying and roasting is smaller, and the mud material in the part with the slow mud flow speed is softer, water is also more, drying and baking shrinkage is also larger. Since the elastic coefficient of the mud is only1% ~ 2%, this large shrinkage difference will cause cracks in the brick.
First of all, we should find out which part of the mud strip is fast and which part is slow, and how much is the difference? The method is: use aboutA 4mm thick steel plate is made into a frame with an inner space slightly larger than the section of the extruded mud strip. In the frame, the mud strip is divided into several small squares of about 30mm × 30mm with a thin steel wire with a diameter of about 1mm, which is used as a mud strip divider. Or mud speed detection plate.
When in use, first extrude a section of mud strip, then cut the mud strip along the mouth of the machine, and put on the mud strip divider. At this time, when extruding the mud strip again, it will be divided into multiple pieces.Small mud strips of 30mm x 30mm. After extruding 1m long, measure the length of each small mud strip respectively. The longest and shortest tolerances are: not more than 50mm for porous bricks; Not more than 30mm for thick-walled hollow bricks; Not more than 20mm for thin-walled hollow bricks; Not more than 10mm for extruded flat tiles.

This mud flow speed should be checked once every time the core is replaced, and the flat tile should be checked once a day.

The test results may have the following types of uneven mud speed:

The speed of up, down, left and right is different, you can move the machine mouth to the side with faster mud speed;

The middle is fast and the periphery is slow. Two pieces of shunt iron cut by triangle can be welded on both sides of the middle of the large blade respectively. If the middle is still slightly fast, the shunt iron is small. A layer of welding rod can be surfacing on the surface or two pieces of larger shunt iron can be replaced. On the contrary, two smaller shunting irons should be replaced. Hollow bricks with large holes can also be used to lengthen the middle core head or put a large nut on the core rod behind the core head to slow down the mud flow;

The middle mud speed is too slow, the middle core head can be shortened, or the middle core head can be replaced by the core plate;

If the mud flow of a rib or an edge is too slow, the inclined surface of the core head facing the rib (edge) can be worn off a little. On the other hand, an electric welding can be welded on the inclined surface of the core head facing the surface. If the ceramic core head is used, an eccentric flat pad can be set on the core rod behind the core head to prevent the mud from flowing too fast;

The mud flow at the "crossroads" where the two ribs meet is too fast. A M10 ~ M12 screw can be welded on the blade facing the crossroads. The length of the screw shall not exceed the plane of the small head of the core. Flat washers with different outer diameters are respectively sleeved on the screw and blocked at the tip of the screw with nuts to adjust the mud flow speed there.

Sawtooth cracks appear at the four corners of the mud strip.

"CORE" IN PRODUCING RECTANGULAR POROUS BRICKS"

Sawtooth cracks appear at the four corners of the mud strip.

"CORE" IN PRODUCING RECTANGULAR POROUS BRICKS"