TURBOVAC Molecular Pump Maintenance Guide

TURBOVAC Turbomolecular Pump: Complete Guide to Installation, Debugging, Troubleshooting, and Maintenance

Introduction: When your turbo molecular pump needs to be replaced or repaired

Turbomolecular pumps are the core equipment for generating high and ultra-high vacuum in semiconductors, analytical instruments, vacuum coating, and research laboratories. The TURBOVAC series (35 LS, 50, 151, 361, 600 C, 1000 C, etc.) of Oerlikon Leybold Vacuum (now part of the Leybold brand) uses grease lubricated bearings and is widely used in leak detection, surface analysis, electron microscopy, and industrial coating due to its high compression ratio, clean oil-free operation, and reliable performance. However, as the running time increases (usually bearing replacement is recommended after 15000 hours), engineers often face faults such as pump failure to start, increased noise, failure to meet maximum pressure standards, overheating shutdown, etc. It is crucial to master fast diagnosis and correct maintenance methods when the original factory maintenance cycle is long or spare parts are discontinued.

This article is based on the official operating manual of the TURBOVAC series, providing a detailed technical guide from safety regulations, installation points, cooling configuration, use of purge gas, start-up and baking, troubleshooting to preventive maintenance to help on-site engineers quickly restore equipment performance.

Safety first: Protection against mechanical, electrical, and thermal hazards

The rotor of the TURBOVAC turbomolecular pump operates at a speed of up to 36000 rpm, storing a large amount of kinetic energy. Once the rotor gets stuck or collides, it will release enormous energy. The manual emphasizes: "If the system malfunctions (such as rotor/stator contact or even rotor collision), rotational energy will be released. To avoid equipment damage and personnel injury, it is necessary to strictly follow the installation instructions in this manual

1.1 Mechanical hazards

It is strictly prohibited to operate the pump without flange connection to the vacuum chamber (such as bench testing). The small diameter connection of the high vacuum flange (such as the DN 40 KF flange of TURBOVAC 50) is not strong enough to prevent the pump from rotating when it suddenly gets stuck. The rotation of the pump can cause leakage in the front stage pipeline. The pump must be additionally fixed to prevent rotation.

The high vacuum flange must be securely connected. The manual provides different brake torque values for different models: TURBOVAC 35 LS/35 LS2 is 150 Nm, 50 is 450 Nm, 151 is 283 Nm, 361 is 580 Nm, 600 C is 1486 Nm, 1000 C is 1500 Nm. The clamping bolts (steel) need to be tightened to 35 Nm, and 12.9 grade bolts are 50 Nm. CF flanges are tightened according to DN 40 CF (15 Nm), DN 63 and above (30 Nm).

The splash guard must always be installed to prevent foreign objects from entering the pump and damaging the rotor.

1.2 Electrical hazards

There is a voltage of up to 400 V on the connecting cable between the frequency converter (TURBOTRONIK) and the pump; The power supply lines for fans, flange heaters, and valves are equipped with main power voltage.

Before carrying out any maintenance, all power sources must be disconnected. Even if the connecting cable is plugged in, the output terminal of TURBOTRONIK may still be live.

1.3 Thermal hazards

The temperature of the pump during operation can exceed 70 ° C (up to 120 ° C), and contact may cause burns. Hot components must be shielded from contact and protective clothing must be worn.

1.4 Material and Substance Hazards

The front-end pipeline must be sealed. Dangerous gas leaks or reactions with air/moisture can pose risks. Pumps that have handled hazardous gases must take appropriate protective measures (gloves, respirators, fume hoods) before opening the interface.

The standard version pump is not suitable for explosive environments. If you need to use it, you must consult the manufacturer.

Installation points: from flange fastening to anti vibration measures

2.1 Installation of high vacuum flange

When using ISO-K flanges, place the O-ring into the centering ring to ensure that the O-ring is flat and free of distortion, and then add the outer ring. For ultra-high vacuum applications, a collar flange with a retainer and a metal sealing gasket are required.

Key torque value (braking torque): This is the torque that the flange connection must withstand when the pump suddenly gets stuck. The manual clearly lists the braking torque for each model, and it is necessary to use a sufficient number and strength of bolts during installation.

Model: Braking torque (Nm), number of clamping bolts

35 LS / 35 LS2 150 4

50 450 6

151 / 151 C 283 8

361 / 361 C 580 8

600 C 1486 10

1000 C (DN 160) 1500 16

1000 C (DN 250) 1500 10

2.2 Anti rotation additional fixation

For the TURBOVAC 50, the KF connection strength of its high vacuum flange is insufficient to resist the rotational torque when stuck. The manual specifically states that "the pump must be additionally fixed to prevent sudden stuck rotation

2.3 Dust and Vibration Prevention