7.2　Removable Hood

7.2.1　The track for cross travelling trolley shall be installed according to the following requirements:

1　The longitudinal center line shall be adjusted，and the measurement by plumb wire should be carried out，with the allowable deviation of 2.0mm.

2　The longitudinal levelness shall be adjusted，and the measurement by leveler or optical instrument should be carried out，with the allowable deviation of 1.0/1000.

3　The elevation shall be adjusted，and the measurement by optical instrument should be carried out，with the allowable deviation of±2.0mm.

4　The height difference of two rail surfaces on the same cross section shall be adjusted，and the measurement by optical instrument should be carried out，with the allowable deviation of 1.0mm.

5　The distance between rails shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of 2.0mm.

7.2.2　The cross travelling trolley for hood installation shall meet the following requirements:

1　The equipment shall be checked.In case that the applied lubricating grease is expired or degenerative or with dirt and it cannot turn flexibly with jamming，it shall be marked at first，and then disassembled and cleaned.Its cleaning and assembly shall conform to the requirement of the design technical document or related requirements of current national standard General Code for Construction and Acceptance of Mechanical Equipment Installation Engineering GB 50231.

2　The span of travel mechanism shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of±2.0mm.The diagonal shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of 5.0mm.The error of wheels'position under the same side sill shall be adjusted，and the measurement by plumb wire should be carried out，with the allowable deviation of 2.0mm.

7.2.3　The removable hood shall be installed according to the following requirements:

1　For the installation of removable hood，the cross travelling trolley shall be at the working position.

2　The longitudinal and horizontal center lines shall be adjusted，and the measurement by plumb wire should be carried out，with the allowable deviation of 3.0mm.The elevation shall be adjusted，and the measurement by optical instrument should be carried out，with the allowable deviation of±5.0mm.The verticality of the lower inlet shall be adjusted，and the measurement by suspension wire should be carried out，with the allowable deviation of 1.0/1000.

3　Its sealing with the lower hood shall be checked according to the design requirement.

4　It shall be connected with the upper flue.The concentricity and parallelism of flanges at the joint shall be adjusted，and the measurement by ruler and feeler gauge should be carried out，with the allowable deviation of the concentricity and parallelism being respectively 2.0mm and 1.5/1000（3.0mm for the overall length）.