Exam Question
Sketch & Describe a piston rod stuffing box incorporated in a two stroke crosshead diesel engine which serves to prevent sludge and dirty oil from entering the crankcase. (16)
Class 4 (4th Engineer)
MEKM
📅 Aug 2023
Reference Answer
### **Principle and Purpose**
The piston rod stuffing box is a critical component fitted on two-stroke crosshead marine diesel engines. Its primary purpose is to seal the space between the crankcase and the under-piston (scavenge) space, which are separated by a diaphragm plate. This separation is essential for two main reasons:
1. **Preventing Crankcase Oil Contamination**: It stops contaminated cylinder lubricating oil, unburnt fuel, carbon deposits, and acidic products of combustion (sludge) from the scavenge space from draining down the piston rod and contaminating the main crankcase lubricating oil system. Contamination can lead to a severe degradation of the oil's properties, causing bearing damage and other machinery failures.
2. **Preventing Crankcase Oil Loss**: It prevents the crankcase lubricating oil, which is splashed onto the piston rod, from being carried upwards into the scavenge space, where it would be burned, leading to excessive oil consumption and fouling of the scavenge ports.
The piston rod stuffing box is a critical component fitted on two-stroke crosshead marine diesel engines. Its primary purpose is to seal the space between the crankcase and the under-piston (scavenge) space, which are separated by a diaphragm plate. This separation is essential for two main reasons:
1. **Preventing Crankcase Oil Contamination**: It stops contaminated cylinder lubricating oil, unburnt fuel, carbon deposits, and acidic products of combustion (sludge) from the scavenge space from draining down the piston rod and contaminating the main crankcase lubricating oil system. Contamination can lead to a severe degradation of the oil's properties, causing bearing damage and other machinery failures.
2. **Preventing Crankcase Oil Loss**: It prevents the crankcase lubricating oil, which is splashed onto the piston rod, from being carried upwards into the scavenge space, where it would be burned, leading to excessive oil consumption and fouling of the scavenge ports.
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