tailieunhanh - Root Cause Failure Analysis Part 9

Tham khảo tài liệu 'root cause failure analysis part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 232 Root Cause Failure Analysis Complete the equipment assembly taking care when compressing the seal into the stuffing box. Seat the gland ring and gasket to the face of the stuffing box by tightening the nuts and bolts evenly and firmly. Be sure the gland ring is not cocked. Tighten the nuts and bolts only enough to form a seal at the gland ring gasket usually finger tight and one half to three quarters of a turn with a wrench. Excessively tightening the gland ring nuts and bolts will cause distortion that will be transmitted to the running face resulting in leaks. If the seal s assembly drawing is not available the proper setting dimension for inside seals can be determined as follows - Establish a reference mark on the shaft or sleeve flush with the face of the stuffing box. - Determine how far the face of the insert will extend into the stuffing-box bore. Take this dimension from the face of the gasket. - Determine the compressed length of the rotary unit by compressing it to the proper spring gap. - This dimension added to the distance the insert extends into the stuffing box gives the seal-setting dimension from the reference mark on the shaft or sleeve to the back of the seal collar. - Outside seals are set with the spring gap equal to the dimension stamped on the seal collar. Cartridge seals are set at the factory and installed as complete assemblies. These assemblies contain spacers that must be removed after being bolted into position and the sleeve collar is in place. Installation of Environmental Controls Mechanical seals often are chosen and designed to operate with environmental controls. If this is the case check the seal s assembly drawing or the equipment s drawing to ensure that all environmental-control piping is properly installed. Seal Startup Procedures Before equipment startup all heating and cooling lines should be operating. These lines also should remain in operation for a short period after equipment shutdown. On double-seal .