Overview
ISO 27892:2010 - "Vacuum technology - Turbomolecular pumps - Measurement of rapid shutdown torque" specifies a standardized, destructive-test method for measuring rapid shutdown torque (also called destructive torque) of turbomolecular and molecular drag pumps that use axial-flow type blades and/or helical channels. The standard focuses on torque about the rotational axis as the primary failure-driving force and defines test setups, measurement equipment, and procedures to assess pump and mounting safety under rotor failure (burst or crash).
Key topics and technical requirements
- Scope and failure modes
- Applies to turbomolecular pumps and molecular drag pumps where gas momentum is produced by axial-flow blades and/or helical channels.
- Two failure types: whole rotor burst (centrifugal destruction of rotor body) and crash (softer failure of rotor or stator blades).
- Other non-torque forces are outside the scope.
- Destructive test preparation
- Notch machining may be applied to concentrate stress so failure occurs near rated speed.
- Target failure rotational frequency: preferably within ±5% of rated; procedure suggests repeat if failure below 95% of rated (recommended measurement window ~95–105%).
- Measurement hardware
- Two torque-cell types:
- Short-tube type with circumferential strain gauges (mean strain used to compute torque).
- Compression-bar type (strain rods) or force-sensor arrays mounted on a stand; total measured force/strain is converted to torque.
- High-bandwidth sensing recommended (strain gauges/force sensors responsive to 0–10 kHz or more) to capture rapid events.
- Test configurations
- Method A: pump fixed to a torque cell attached to a rigid test frame/base plate anchored to floor.
- Method B: torque cell fixed so pump can twist relative to floor/base plate; torque cell must not plastically deform.
- Procedures and observations
- Record rotational frequency at failure, measured torque, inspect for housing cracks/deformation, check inlet flange bolt shearing, and perform leak testing on the pump body.
- Referenced terminology
- Uses vocabulary from ISO 3529-2 for pump and vacuum terms.
Applications and users
- Pump manufacturers - validate rotor and housing safety, comparative product testing.
- Test laboratories and R&D - characterize failure torque, optimize rotor designs and safety margins.
- Vacuum system integrators and safety engineers - determine correct mounting and anchoring specifications; verify mounting bolts and base safety under worst-case failure.
- Procurement and compliance teams - include measured rapid-shutdown torque requirements in specifications and contracts.
Related standards
- ISO 3529-2 (Vocabulary - Vacuum pumps and related terms) is normative and provides defined terms used in ISO 27892:2010.
Keywords: ISO 27892:2010, turbomolecular pumps, rapid shutdown torque, destructive test, vacuum technology, torque cell, strain gauges, burst test, crash test, molecular drag pumps.