SULZER 2RC-4A-4N-67 vacuum blower Trouble shooting & solving
Vacuum Dewatering papermill machine wet boxes & presses.
Problem: Regularly tripped due to high vibration value’s caused limitation of production capacity because of the lower amount of dewatering per min.
- Suction volume : Suction I :852 Suction II : 150 Suction III : 198 Suction IV : 280 Suction V :810 m³/Min
- Power: 1250 kw
- RPM : 8000
- Atmospheric pressure : 735 mm Hg.
- Installation: 1970
- Industry: Pulp & Paper
Assembled SULZER 2RC-4A-4N-67 vacuum blower
1) Clearly situating the problem using engineering calculations and simulations
After analysing the vibration spectrum within Energetics’ engineering, we came to the conclusion that the vacuum blower was experiencing high vibrations due to the oil whirl phenomenon. The customer had apparently made several attempts in the past to adjust the bearing design without any effect.
First, we scanned the rotor completely to run a rotor dynamic simulation in order to understand exactly what happens to the rotor during operation.
Scanning and 3D modelling of the rotor
The compressor experiences significant sub synchronous vibrations during operation under transient events. The baseline rotor lateral dynamics with cylindrical profile bearings and measured radial clearance was calculated. The results where compared with the measured data. High instability risk corresponding with measured instability trip events has been identified. Furthermore, revised design with new lemon profile bearings is proposed. Minimum & maximum bearing stiffness were analysed. Based on analysis results ( see below) it is concluded that lemon type profile bearings will provide a solution to instability that has been occurring in operation, rotor is fully expected to provide reliable service.
2) Solution simulated to solve the vibrations issue
Diagram of lemon type bearings
3) New bearing design is developed according the calculations and data collecting from the original bearings.
A geometrical check on the existing bearings is executed:
3D geometrical inspections on existing bearings for reverse engineering purposes.
New bearing design is developed according the calculations and data collecting from the original bearings.
4) SULZER 2RC-4A-4N-67 rotor Inspection
Visual income inspection @ Energetic workshop
Income run out control
Glass pearl cleaning by blasting
Balance check ISO 1940-1 dynamic G 1
Electronical and mechanical run out check and improving by burnishing probe places
Magnetic particle test (MPT)of complete rotor inclusive degaussing.
Assembly SULZER 2RC-4A-4N-67 vacuum blower on site of rotor and clearance check of seals.
Alignment check SULZER 2RC-4A-4N-67 vacuum blower & preparation for start up.
The trouble shooting activity was successful because of the Engineering and babbitt bearing production capability of Energetic NV.
Energetic NV has the possibility to execute regular services and inspections on the Sulzer vacuum blowers and also on the Sulzer evaporating cycle compressors.