[Q&A Question 168] 2018.06.17

(1) Breakage of the connecting rod screw or damage to the connecting rod, (2) Breakage of the compressor frame, (3) The piston gets stuck or wedged inside the cylinder, (4) Breakage of the compressor crankshaft, (5) Freezing and cracking of the cylinder, (6) Breakage of the compressor flywheel, (7) Damage to the drive motor.

Abnormal exhaust temperature, overheating, breakdown, combustion, explosion. .

I. Abnormal exhaust temperature 　Abnormal exhaust temperature refers to a value that is higher than the design value. 　　Factors that affect the increase in exhaust temperature include intake air temperature, pressure ratio, and compression index (for air, the compression index K=1.4). 　　Factors that affect high intake temperatures include low intercooling efficiency, or excessive scale buildup in the intercooler, which hinders heat exchange; as a result, the intake temperature in subsequent stages will inevitably be high, and so will the exhaust temperature. 　　Air leakage in the valve and piston rings not only leads to an increase in exhaust temperature but also causes changes in the pressure between stages; whenever the pressure ratio is higher than normal, the exhaust temperature rises. Furthermore, in water-cooled machines, a lack of water or insufficient water volume will cause the exhaust temperature to rise. II. Overheating fault 　　When the temperature at points of friction such as the crankshaft and bearings, the crosshead and slide plates, as well as the packing and piston rod, exceeds the specified value, it is referred to as overheating. The consequences of overheating are, first, an accelerated wear between the friction pairs, and second, the continuous accumulation of heat from overheating, which can lead to the burning of the friction surfaces as well as seizure, resulting in serious machine failures. 　　The main reasons for bearing overheating are: uneven fit between the bearing and the shaft journal or an insufficient contact area ； Bearing misalignment, crankshaft bending, torsion ； Too low viscosity of lubricating oil, blockage in the oil circuits, faults in the oil pump resulting in a lack of oil supply, etc ； During installation, leveling was not done, the gaps were not properly adjusted, the main shaft and the motor shaft were not aligned, and there was tilting between the two shafts. III. Fracture accidents The main locations where fracture accidents occur are: Crankshaft fractures: Most of these fractures take place at the transition zone where the shaft journal meets the curved end of the crank arm ； Breakage of the connecting rod: Breakage of the connecting rod screw ； Cracking of cylinders and cylinder heads: The main reason is that in water-cooled machines, if the cooling water inside the cylinders and cylinder heads is not drained after shutdown in winter, the water will freeze and cause the cylinders and cylinder heads to crack ； The piston rod is broken. IV. Breakage of the piston rod The main areas where breakage occurs are at the threads connecting to the crosshead and at the threads used to secure the piston; these two areas represent the weak points of the piston rod. Breakages tend to happen frequently due to design flaws, careless manufacturing practices, or issues related to operation. If there are no issues with the design, manufacturing, or material quality, the pre-tensioning force during installation should not be too high; otherwise, when the maximum force reaches the yield limit, the piston rod will break. After long-term operation, due to excessive wear of the cylinders, the pistons in the horizontal row will sink, thereby creating additional stress at the connection threads; continued operation may lead to the breakage of the piston rod, a point that requires special attention during maintenance. Furthermore, if the piston rod is subjected to a severe impact due to damage in other areas, it is possible for the piston rod to break. V. Combustion and explosion accidents Oil-lubricated compressors often suffer from carbon buildup, as this not only causes the piston rings to get stuck in their grooves and disrupts the proper functioning of the valves, but it also reduces the area of the airflow channels and increases resistance. Under certain conditions, this carbon buildup can catch fire, leading to explosions in the compressor. Therefore, too much lubricating oil cannot be supplied into the cylinder, and gases that have not been properly filtered and contain a large amount of dust must not be drawn into the cylinder; otherwise, carbon deposits will form and come into contact with gases containing large amounts of volatiles, leading to an explosion. To prevent fires and explosions, it is essential to plan regular maintenance and clean the oil deposits in the gas storage tanks and pipelines on a periodic basis.

(1) Breakage of the connecting rod screw or damage to the connecting rod, (2) Breakage of the compressor frame, (3) The piston gets stuck or wedged inside the cylinder, (4) Breakage of the compressor crankshaft

(1) Breakage of the connecting rod screw or damage to the connecting rod, (2) Breakage of the compressor frame, (3) The piston getting stuck or wedged inside the cylinder, (4) Breakage of the compressor crankshaft, (5) Freezing and cracking of the cylinder, (6) Breakage of the compressor flywheel, (7) Damage to the electric motor.

(1) Breakage of the connecting rod screw or damage to the connecting rod, (2) Breakage of the compressor frame, (3) The piston gets stuck or wedged inside the cylinder, (4) Breakage of the compressor crankshaft, (5) Freezing and cracking of the cylinder, (6) Breakage of the compressor flywheel, (7) Damage to the drive motor.

(1) Breakage of the connecting rod screw or damage to the connecting rod, (2) Breakage of the compressor frame, (3) The piston gets stuck or wedged inside the cylinder, (4) Breakage of the compressor crankshaft, (5) Freezing and cracking of the cylinder, (6) Breakage of the compressor flywheel, (7) Damage to the drive motor

Abnormal vibrations caused by severe cylinder collision due to liquid presence, worn piston rings, a sinking piston rod, damaged bearings, and broken connecting rods; high vent temperatures or hydrogen leaks resulting from insufficient pressure of the isolating nitrogen gas; damage to the engine block caused by excessive compression ratios and valve temperatures resulting from undetected leaks in the intake valves

1. Liquid in the cylinder, resulting in cylinder collision accidents. 2. Mechanical failures in the engine block, such as the crankshaft or connecting rods coming loose or bending. 3. Blockage in the outlet pipeline, leading to pressure buildup; this can cause the safety valve to activate or result in cylinder explosion accidents. 4. Improper lubrication or loading conditions, leading to piston damage due to friction with the cylinder walls

1. Cylinder collision 2. Leakage and fire 3. Burning of bearing shells 4. Explosion caused by the entry of incompressible substances into the cylinder