Cast iron grates,also known as manhole covers,are used to cover roads or deep wells in homes to prevent people or objects from falling.According to material,it can be divided into metal manhole covers,fiber cement concrete manhole covers,resin manhole covers,etc.

　　The correct installation steps for cast iron rainwater grates are as follows:

　　1.After the second layer of water stabilization is laid and the roller compaction is completed,the rainwater well will be excavated manually.

　　2.The rainwater inlet is made of cast-in-place concrete with a net clearance of 700mm*400mm square well.The well is 30cm thick.Pour to a height of 2 centimeters higher than the second layer of water stable surface,without affecting the paving of the first layer of asphalt,and then cover the rainwater outlet with steel plates.

　　3.After pouring the rainwater outlet,first lay a layer of asphalt concrete,and then install the rainwater grate.After the asphalt concrete to be laid cools down,manually excavate the asphalt,remove the steel plate,cut the edges of the asphalt concrete around the rainwater outlet,leave the outer dimensions of the rainwater outlet,and remove debris inside the rainwater outlet.

　　Cast iron rainwater grate

　　4.After checking the elevation of the top surface of the rainwater outlet,sprinkle water on the concrete top surface to moisten it.Use 1:3 cement mortar to place a 2cm thick mortar at the location where the grating needs to be installed,and then place the rainwater outlet grating base.The inner edge of the base should be covered with mortar.During installation,the base should be kept flat,and the grate base should be firmly grounded without looseness.

　　5.After the installation of the grate,a C20 concrete protective ring should be poured around the rainwater inlet grate.The top surface of the concrete protective ring should be 2-3cm lower than the top surface of the grate,and it should be leveled when laying a second layer of asphalt concrete surface layer.The protective ring concrete needs to be watered and cured.

　　6.When paving asphalt pavement,the rainwater inlet should be connected to the rainwater grate within a range of 100cm before and after the road direction,and within a range of 50cm horizontally.During road construction,construction machines are not allowed to directly crush the grate.The area around the grate is manually paved and compacted with small machinery.

　　7.In order to maintain the appearance of the water grate and clear handwriting patterns,the manufacturer of cast iron rainwater grates should protect the surface of the water grate when pouring asphalt or cement on the road surface to avoid contamination and inability to clean.

　　8.After pouring concrete or laying asphalt for the rainwater inlet protection ring,the grate should be opened and cleaned in a timely manner to avoid mortar or asphalt from pouring the water grate into the well base,so as not to affect the future opening.