Posted on by

Agilent TwisTorr 84 FS Turbomolecular Pump User Manual Guide

Introduction

The Agilent TwisTorr 84 FS is a high-performance turbomolecular pump designed for high vacuum and ultra-high vacuum (UHV) applications. With a maximum rotational speed of 81,000 rpm and advanced Agilent hybrid bearing technology, this pump is widely used in research, mass spectrometry, surface science, semiconductor processes, and coating equipment.

This article provides a comprehensive usage guide, covering operating principles and features, installation and calibration, maintenance, troubleshooting, and a bearing failure repair case study. It is intended for engineers, technicians, and third-party service providers.

I. Principles and Features of the Pump

1. Operating Principle

  • Momentum Transfer: Gas molecules collide with the high-speed rotating rotor blades, gaining directional momentum and moving from the inlet toward the outlet.
  • Rotor/Stator Stages: The pump contains multiple alternating rotor and stator stages, which compress molecules step by step for efficient pumping.
  • Backing Pump Requirement: A turbomolecular pump cannot start from atmospheric pressure. A mechanical or dry pump is required to reduce the pressure below approximately 10⁻² mbar before the turbo pump is started.

2. Key Features of TwisTorr 84 FS

  • Oil-free operation: No oil contamination, ideal for clean vacuum applications.
  • High speed and efficiency: Up to 81,000 rpm, pumping speed ~84 L/s (for nitrogen).
  • Flexible installation: Available with ISO-K/CF flanges, mountable in any orientation.
  • Controller options: Rack-mount RS232/485, Profibus, or on-board 110/220 V and 24 V controllers.
  • Cooling and protection: Optional water cooling, air cooling kits, and purge/vent functions to protect bearings.
  • Applications: Mass spectrometry, SEM/TEM, thin film deposition, plasma processes, vacuum research systems.

II. Installation and Calibration

1. Preparation

  • Environment: Temperature 5–35 °C, relative humidity 0–90% non-condensing, avoid corrosive gases and strong electromagnetic fields.
  • Storage: During transport or storage, temperature range –40 to 70 °C, maximum storage 12 months.
  • Handling: Do not touch vacuum surfaces with bare hands; always use clean gloves.

2. Mechanical Installation

  • Flange connection:
    • ISO-K 63 flange requires 4 clamps, tightened to 22 Nm.
    • CF flange requires Agilent original hardware, capable of withstanding 250 Nm torque.
  • Positioning: Can be installed in any orientation but must be rigidly fixed to prevent vibration.
  • Seals: Ensure O-rings or gaskets are free of damage and contamination.

3. Electrical Connections

  • Use Agilent-approved controllers and cables.
  • Power voltage and frequency must match the controller rating.
  • Power cable must be easily accessible to disconnect in case of emergency.

4. Cooling and Auxiliary Devices

  • Install air cooling kit or water cooling kit depending on the environment.
  • Use high-purity nitrogen purge to protect bearings.
  • Connect an appropriate backing pump to the foreline.

5. Calibration and Start-Up

  • Always use Soft Start mode during the first start-up to reduce stress on the rotor.
  • Monitor speed and current during ramp-up; speed should increase smoothly while current decreases.
  • Verify system performance by checking the ultimate pressure.

III. Maintenance and Service

1. General Maintenance Policy

  • TwisTorr 84 FS is officially classified as maintenance-free for users.
  • Internal service, including bearing replacement, must be carried out only by Agilent or authorized service providers.

2. Operational Guidelines

  • Do not pump liquids, solid particles, or corrosive gases.
  • Never expose the rotor to sudden venting or reverse pressure shocks.
  • Check cooling systems regularly to ensure fans or water flow are functioning.
  • If the pump is unused for months, run it once a month to maintain lubrication and rotor balance.

3. Storage and Transport

  • Always use original protective packaging.
  • Store in clean, dry, dust-free conditions.

IV. Common Faults and Troubleshooting

1. Electrical Issues

  • Pump does not start: Power supply issue, controller malfunction, or missing start command.
  • Frequent shutdowns: Overcurrent, overvoltage, or overheating.
  • Insufficient speed: Backing pump failure, drive fault, or rotor friction.

2. Mechanical Issues

  • Rotor friction or seizure: Damaged bearings, foreign objects in the pump, or incorrect mounting stress.
  • Abnormal noise or vibration: Bearing wear or rotor imbalance.
  • Reduced pumping speed: Contamination inside the pump or insufficient rotor speed.

3. Environmental/System Issues

  • Overtemperature alarms: Inadequate cooling or high ambient temperature.
  • Failure to reach pressure: Leaks or system contamination.

V. Case Study: Bearing Failure

1. Symptoms

  • The pump rotor could not be rotated manually after disassembly.
  • Abnormal metallic noise and inability to reach rated speed.

2. Initial Diagnosis

  • High probability of bearing seizure or failure.
  • The pump, manufactured in 2019, had been in service for several years—approaching the expected bearing lifetime.

3. Repair Options

  • Factory repair: Complete bearing replacement and rotor balancing; cost approx. USD 3,000–5,000 with 12-month warranty.
  • Third-party repair: Ceramic hybrid bearing replacement; cost approx. USD 1,500–2,500 with 3–6 month warranty (some providers up to 12 months).
  • Do-it-yourself: Not recommended. Requires cleanroom and balancing equipment. Very high risk of premature failure.

4. Typical Repair Procedure (Third-Party Example)

  1. Disassemble the pump in a cleanroom.
  2. Remove the damaged bearings using specialized tools.
  3. Install new ceramic hybrid bearings.
  4. Perform rotor balancing and calibration.
  5. Clean and reassemble the pump.
  6. Test vacuum performance under extended operation.

5. Conclusion

Bearing damage is the most common mechanical failure in turbomolecular pumps. Professional repair can restore full performance, but warranty length and cost vary significantly depending on service channels.

VI. Conclusion

The Agilent TwisTorr 84 FS turbomolecular pump is a high-speed, clean, and reliable vacuum solution. Correct installation, calibration, preventive maintenance, and troubleshooting are essential for long-term stable operation.

Bearing failure is the most frequent fault and requires professional service. Users should carefully evaluate factory vs third-party repair depending on cost, warranty, and equipment requirements.

By following this guide, users can significantly extend pump lifetime, reduce downtime, and ensure high-quality vacuum performance for scientific and industrial applications.