Turbomolecular Pump Cleaning via Pressure-Induced Deposit Sublimation
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Solution Overview
Problem
Existing vacuum pumps, particularly turbomolecular pumps, face challenges in achieving sufficient cleaning performance due to deposits that accumulate and degrade pump performance, despite temperature control mechanisms.
Innovation Solution
The vacuum pump system incorporates a heating means, gas introduction means, and pressure control means to alternate between operation modes, including a cleaning mode that increases pressure and temperature to sublimation levels, facilitating deposit sublimation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature is increased to sublimation level to improve cleaning performance, then deposit removal efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic alternation between high-temperature sublimation phases and cooling phases. The heating means operates intermittently to sublime deposits, then stops to allow cooling, creating a cyclic cleaning process that achieves effective deposit removal while reducing continuous energy consumption compared to sustained high-temperature operation.
Solution Approach 2:
The patent utilizes the phase transition of deposits from solid to gas (sublimation) by controlling temperature and pressure. By increasing temperature to sublimation level and maintaining appropriate pressure conditions, the deposits undergo phase transition and are removed, providing an energy-efficient cleaning mechanism that leverages natural material properties rather than requiring mechanical removal forces.
2Reliability
If pressure is increased to cause intermediate flow or viscous flow for deposit sublimation, then cleaning effectiveness is improved, but pump performance degradation occurs
Solution Approach 1:
The patent employs periodic switching between high-pressure cleaning mode and normal vacuum operation mode. During cleaning cycles, pressure is increased to intermediate or viscous flow ranges to facilitate deposit sublimation. Between cleaning cycles, the system returns to molecular flow conditions for normal vacuum performance, thus achieving effective cleaning while maintaining overall pump productivity.
Solution Approach 2:
The patent dynamically adjusts operating pressure and temperature parameters based on the cleaning needs. The pressure control means and temperature control means coordinate to create optimal conditions for sublimation when cleaning is required, then return to standard operating parameters for vacuum maintenance, allowing the system to adapt its behavior to different operational states.
3Reliability
If heating means is activated to sublime deposits, then cleaning performance is improved, but thermal stress on pump components increases
Solution Approach 1:
The heating means operates in periodic cycles rather than continuously. High-temperature heating phases are alternated with cooling phases, allowing thermal stress to dissipate between heating events. This intermittent heating approach achieves effective deposit sublimation while preventing excessive thermal accumulation and stress that would occur with continuous high-temperature operation.
Solution Approach 2:
The patent carefully controls and adjusts temperature parameters within optimal ranges for sublimation while avoiding excessive temperatures. By precisely managing the temperature profile and heating duration, the system achieves effective cleaning through parameter optimization that balances cleaning efficacy with component thermal stress limitations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances cleaning performance by effectively sublimating and removing deposits, improving the vacuum pump's operational efficiency and longevity.
Implementation Method 1
a cleaning mode that is capable of sublimating deposits in the vacuum pump
Implementation Method 2
increase a pressure in at least a part of an interior of the vacuum pump to a pressure region with which a temperature is greater than or equal to a sublimation temperature of the deposits in the vacuum pump and that causes an intermediate flow or a viscous flow
Data Source
AI summary
A vacuum pump includes a heater, purge gas introduction ports, a purge gas valve, and an exhaust valve. In a cleaning operation mode, at least one of the heater, the purge gas valve, and the exhaust valve is controlled, and a pressure in at least a part of an interior of the turbomolecular pump is increased to a pressure region with which a temperature is greater than or equal to a sublimation temperature of the deposits in the turbomolecular pump and that causes an intermediate flow or a viscous flow.