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.

Technical details

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

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.

SULZER 2RC 4A 4N 67 Scanning and 3D modelling of the rotor

Scanning and 3D modelling of the rotor

SULZER 2RC 4A 4N 67 Scanning and 3D modelling of the rotor 3

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

SULZER 2RC 4A 4N 67 (1)

SULZER 2RC 4A 4N 67 (2)

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:

SULZER 2RC 4A 4N 67 3D geometrical inspections on existing bearings for reverse engineering purposes

SULZER 2RC 4A 4N 67 3D geometrical inspections on existing bearings for reverse engineering purposes 2

3D geometrical inspections on existing bearings for reverse engineering purposes.

SULZER 2RC 4A 4N 67 02 New bearing design is developed according the calculations and data collecting from the original bearings.

4) SULZER 2RC-4A-4N-67 rotor Inspection

SULZER 2RC 4A 4N 67 Visual income inspection @ Energetic workshop

Visual income inspection @ Energetic workshop

SULZER 2RC 4A 4N 67 Income run out control

Income run out control

SULZER 2RC 4A 4N 67 Glass pearl cleaning by blasting

Glass pearl cleaning by blasting

SULZER 2RC 4A 4N 67 Balance check ISO 1940 1 dynamic G 1

Balance check ISO 1940-1 dynamic G 1

SULZER 2RC 4A 4N 67 Electronical and mechanical run out check and improving by burnishing probe places
Electronical and mechanical run out check and improving by burnishing probe places

SULZER 2RC 4A 4N 67 Magnetic particle test (MPT)of complete rotor inclusive degaussing

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
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

Alignment check SULZER 2RC-4A-4N-67 vacuum blower & preparation for start up.

5) Conclusion

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.