Common cylinder faults and causes

Common cylinder failure problems and causes

⒈The cylinder is cast, and the cylinder must undergo aging treatment after leaving the factory, so that the cylinder will survive the casting process. The internal stress generated is completely eliminated. If the aging time is short, the processed cylinder will be deformed in subsequent operations.

⒉ The stress on the cylinder during operation is very complex. In addition to the static load such as the pressure difference between the gas inside and outside the cylinder and the weight of the components installed in it, it also has to bear the impact of the steam flowing out of the stator vane. The reaction force of the stationary part and the force on the cylinder under the hot and cold conditions of various connecting pipes. Under the interaction of these forces, the cylinder is prone to plastic deformation and leakage.

⒊The load of the cylinder increases or decreases too quickly, especially when the temperature changes greatly during rapid startup, shutdown, and changes in working conditions, incorrect cylinder warming methods, premature opening of the insulation layer during shutdown and maintenance, etc., etc., etc. Large thermal stress and thermal deformation are generated in the cylinder and on the flange.

⒋ The cylinder produced stress during the machining process or after repair welding, but the cylinder was not tempered to eliminate it, resulting in large residual stress in the cylinder and permanent damage during operation. Deformation.

⒌During the installation or maintenance process, due to the maintenance process and maintenance technology, the expansion gaps of the inner cylinder, cylinder partition, partition sleeve and steam seal sleeve are inappropriate, or the hanging lug pressure plate The expansion gap is inappropriate, and a huge expansion force will be generated after operation to deform the cylinder.

⒍The cylinder sealant used is of poor quality, has too many impurities, or is of the wrong model;if there are hard impurity particles in the cylinder sealant, it will make it difficult for the sealing surface to be tightly combined.

⒎The tightening force of the cylinder bolts is insufficient or the material of the bolts is unqualified. The tightness of the cylinder joint surface is mainly achieved by the tightening force of the bolts. The thermal stress and high temperature generated when the unit starts and stops or when the load is increased or decreased will cause the stress of the bolts to relax. If the stress is insufficient, the pretightening force of the bolts will gradually decrease. If the bolt material of the cylinder is not good, the bolts will be stretched under the action of thermal stress and cylinder expansion force during long-term operation, and plastic deformation or fracture will occur. The tightening force will be insufficient, causing the cylinder to leak.

⒏The tightening sequence of cylinder bolts is incorrect. When tightening general cylinder bolts, they are tightened from the middle to both sides at the same time, that is, they are tightened from the maximum vertical arc or the place where the force deformation is the greatest. This will move the gap at the maximum deformation to the free space at the front and rear of the cylinder. The end is transferred, and the final gap gradually disappears. If it is tightened from both sides to the middle, the gaps will be concentrated in the middle, and the cylinder joint surface will form an arc-shaped gap, causing steam leakage.

Internal and external leakage in the cylinder is generally caused by eccentric installation of the piston rod, insufficient supply of lubricating oil, wear or damage of the sealing ring and sealing ring, impurities in the cylinder and scars on the piston rod. Therefore, when there is internal or external leakage in the cylinder, the center of the piston rod should be readjusted to ensure the coaxiality of the piston rod and the cylinder barrel;the lubricator must be regularly checked to see if it works reliably to ensure that the actuator is well lubricated;when sealing When rings and sealing rings are worn or damaged, they must be replaced in time;if there are impurities in the cylinder, they should be removed in time;if there are scratches on the piston rod, they should be replaced with new ones.

Insufficient output force and unstable movement of the cylinder are generally caused by the stuck piston or piston rod, poor lubrication, insufficient air supply, or condensed water and impurities in the cylinder. In this regard, the center of the piston rod should be adjusted;check whether the lubricator works reliably;and whether the air supply pipeline is blocked. When there is condensed water and impurities in the cylinder, they should be removed in time.

The poor buffering effect of the cylinder is generally caused by the wear of the buffer sealing ring or damage of the adjusting screw. At this time, the sealing ring and adjusting screw should be replaced.

Damage to the piston rod and cylinder head of the cylinder is generally caused by the eccentric installation of the piston rod or the failure of the buffer mechanism. In this regard, the center position of the piston rod should be adjusted;the buffer seal ring or adjusting screw should be replaced.