6.5　Ore Mill

6.5.1　The installation of main bearing base plate shall be in accordance with the following requirements:

1　Where the horizontal width between centers of two base plates is less than 5，000mm，the allowable deviation for longitudinal and horizontal centerlines shall be±1.0mm；when width between centers is 5，000mm-10，000mm，the allowable deviation for longitudinal and horizontal centerlines shall be±1.5mm；when width between centers is more than 10，000mm，the allowable deviation for longitudinal and horizontal centerlines shall be±2.0mm；

2　The maximum allowable deviation for horizontal positions of two bearing base plates shall be 1.0mm；the maximum allowable deviation for the distance between horizontal centerlines shall be 0.5mm；

3　The maximum allowable deviation for levelness of main bearing base plate shall be 0.1/1000；the maximum allowable deviation for relative elevation of two base plates shall be 0.5mm，and it shall be ensured that the feed end is higher than the discharge end.

6.5.2　The installation of main bearing block shall be in accordance with the following requirements:

1　The main bearing shall evenly contact with the bearing base plate all round，with local clearance not more than 0.1mm when checking with a feeler gauge；

2　The maximum allowable deviation for coaxiality of two main bearing blocks shall be 1.0mm.

6.5.3　The main bearing bush spherical surface and the bearing block spherical surface shall be in good contact and rotate flexibly，and the assembly of them shall be in accordance with the following requirements:

1　There shall be a wedge clearance remained around the two fit spherical surfaces and its depth should be 25mm-50mm and the edge clearance should be 0.2mm-1.5mm；

2　The circumferential contact wrap angle of two fit spherical surfaces shall not be less than 45°；the axial contact width shall not be more than 1/3 of that of spherical surface base and not be less than 10mm；

3　Contact spots of contact surface shall be evenly and continuously distributed；

4　When assembling main bearing and bearing block，lubricating oil mixed with graphite or molybdenum disulfide grease can be evenly applied on the bearing spherical surface；

5　When the fit contact does not meet the requirements of Items 2，3 of this Article，scraping shall be done within the contact zone；its contact spots shall be evenly and continuously distributed，and the distance shall not be more than 15mm.

6.5.4　The assembly of main bearing bush and hollow shaft shall be in accordance with the following requirements:

1　Contact angle shall be in accordance with the requirements of design documents and should be 70°-90° if no design requirements available；

2　After scraping of bearing other than hydrostatic bearing or dynamic pressure bearing，the quantity of contact points on each contact surface within an area of 25mm×25mm should be 2-4.

6.5.5　The pressure test of main bearing bush cooling water system and high pressure oil system shall be in accordance with relevant requirements of current national standard GB 50235 Code for Construction of Industrial Metallic Piping Engineering.

6.5.6　The installation of cylinder and end cover shall be in accordance with the following requirements:

1　Cylinder and end cover shall be checked before assembly.If no design requirements available，the deviation for straightness of cylinder surface shall not be more than 0.1% of the total length of cylinder，and the deviation for roundness of two ends of cylinder shall not be more 0.15% of the cylinder diameter；

2　When assembling cylinder and end cover，junction surfaces shall be cleaned and they shall closely contact without adjusting gasket；

3　Cylinder and end cover shall be assembled in accordance with markings made when leaving factory，and all positioning pins shall be installed；bolts shall be evenly tightened after the assembly requirements are met.

6.5.7　Check that the two hollow shafts are in accordance with the following requirements:

1　The axial clearance between the shoulders of two hollow shafts and the main bearing shall meet the requirements specified in the equipment technical documents；

2　The maximum allowable deviation for relative elevation of generating line on the two hollow shafts shall be 1.0mm；the maximum allowable deviation for installation levelness of two hollow shafts shall be 0.2/1000；the feed end shall be higher than the discharge end，and the height difference shall meet the requirements of equipment technical documents；

3　The axes of two hollow shafts shall be on the same straight line；check indirectly on the end face of main bearing with a dial indicator，and the end face runout（Fig.6.5.7）of main bearing shall be in accordance with those specified in Table 6.5.7 of this code.

6.5.8　The installation of toothed ring shall be in accordance with the following requirements:

1　The monolithic toothed ring shall be installed on the cylinder before the cylinder is installed on the main bearing；the split type toothed ring shall be installed on the cylinder after the cylinder is installed on the main bearing；

2　The finished surface of toothed ring and the flange surface connecting with the cylinder shall be cleaned and processed，and it shall be ensured that the end face of toothed ring closely fits with the cylinder flange，with the clearance not more than 0.15mm；

3　The clearance at the joint of the split type toothed ring should be no more than 0.10mm；

4　The circular pitch at the joint of the split type toothed ring shall be in accordance with the requirements specified in the equipment technical documents，and the allowable deviation shall be±0.005 modulus；

5　The radial runout of toothed ring shall be no more than 0.25mm for every-meter pitch diameter；

Check the end face circular runout of toothed ring which shall be no more than 0.35mm for everymeter pitch diameter.

6.5.9　The installation of lining plate and grid plate shall be in accordance with the following requirements:

1　When directional lining plates are assembled，their directions and locations shall be in accordance with the requirements specified in the equipment technical documents；

2　The lining plates inside the cylinder shall be so arranged that no circular clearance will be formed；wooden wedge may be used to wedge for wet work and materials such as iron wedge or cement may be used to wedge for dry work；and the clearance between adjacent lining plates shall not be more than 15mm.

3　A sealing gasket and a washer shall be placed under the bolt for fixing lining plate；

4　When assembling the grid plate，the bigger end of the screen opening shall face the discharge end.

6.5.10　When installing the transmission gear，it shall be adjusted with ore mill axis as the reference，and the back lash，top clearance and contact between the small gear and the big ore mill gear shall be in accordance with relevant requirements of design documents and current national standard GB 50231 General Code for Construction and Acceptance of Mechanical Equipment Installation Engineering.

6.5.11　After assembly，the gear cover shall be free from oil leakage or collision with the gear.

6.5.12　When assembling the feeding hopper of the dry-type ore mill or the feeding pipe of the air-swept ore mill，the connection shall be sealed properly and leak-free，and the joint shall be rotating flexibly if it is rotatable.

6.5.13　Test run shall be in accordance with the following requirements:

1　No-load test run shall meet the requirements of Article 3.0.12 in this code；

2　During the test run，stop the mill for check after running for 15min for the first time and it shall be cooled for 30min after confirming everything is normal；stop it for check after running for 30min for the second time and it shall be cooled for 30min after confirming everything is normal；it shall continuously run for 2h for the third time，and the temperature，electricity current，voltage，rotation speed and vibration of each part shall be measured every 30min during running；

3　During the test run，the lining plate shall be free of knock.