Cryopump Cool-Down Control with High-Temperature Stage Relief

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Solution Overview

Problem

Cryopumps face challenges in achieving a rapid temperature difference between high-temperature and low-temperature stages during the cool-down process, leading to prolonged downtime due to the need for extensive temperature adjustments.

Innovation Solution

A cryopump system with a control unit that selectively provides a cooling relief effect to the high-temperature stage during the cool-down operation, allowing for rapid temperature adjustments between the high-temperature and low-temperature stages by managing the flow of operating gas through the compressor's flow channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the cryopump is cooled from room temperature to cryogenic temperature to initiate vacuum pumping operation, then the vacuum pumping function is enabled, but the cool-down time becomes excessively long due to the difficulty in creating a large temperature difference between high-temperature stage and low-temperature stage

Engineering Contradiction:

Improvetemperature difference between high-temperature stage and low-temperature stageVSAvoidcool-down time

Core Design Contradiction:

TemperatureVSLoss of time

Solution Approach 1:

The control unit performs preliminary cooling of the high-temperature stage before the low-temperature stage reaches its target temperature. This advance action allows the high-temperature stage to be pre-cooled, reducing the subsequent temperature adjustment time when the low-temperature stage finishes cooling. The control unit monitors temperatures and initiates high-temperature stage cooling in advance, thereby shortening the overall cool-down time without compromising the required temperature difference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control unit dynamically adjusts the cooling operation based on real-time temperature measurements. It continuously monitors the temperatures of both stages and adaptively controls the cooling process, switching between different cooling modes (cooling both stages simultaneously, cooling only low-temperature stage, or cooling only high-temperature stage) to optimize the temperature difference creation process and minimize cool-down time.

Inventive Principle:

Principle #15Dynamics

2Speed

If the high-temperature stage is cooled to a temperature lower than the target temperature while waiting for the low-temperature stage to reach its target temperature, then the temperature difference can be established faster, but the high-temperature stage requires additional time to be raised back to the target temperature

Engineering Contradiction:

Improvespeed of creating temperature differenceVSAvoidtemperature adjustment time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control unit continuously monitors the temperatures of both stages and uses this feedback to make real-time decisions about cooling operations. When the low-temperature stage approaches its target temperature, the control unit receives temperature feedback and adjusts the high-temperature stage cooling accordingly, preventing excessive cooling and minimizing the time needed for temperature adjustment to the target value.

Inventive Principle:

Principle #23Feedback

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 significantly shortens the cool-down time of the cryopump, reducing downtime by enabling faster temperature equilibration between the stages without requiring significant modifications to the refrigerator or compressor design.

Implementation Method 1

a refrigerator (16) provided with a high-temperature stage for cooling the high-temperature cryopanel (19) and a low-temperature stage for cooling the low-temperature cryopanel (18)

Methodology Applied

Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 2

The cooling system (15) includes: a refrigerator (16) provided with a high-temperature stage for cooling the high-temperature cryopanel (19)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The cooling system (15) is configured to provide a cooling relief effect selectively to the high-temperature stage at least temporarily in the cool-down operation

Methodology Applied

Scientific EffectCooling relief effect:

Data Source

PatentUS10273949B2Cryopump and method of operating the cryopump

Publication Date: 2019.04.30 SUMITOMO HEAVY IND LTD

AI summary

A method of operating a cryopump includes: cooling a cryopanel from an initial temperature higher than a cryogenic temperature for a vacuum pumping operation to the cryogenic temperature by using a refrigerator; and after the cooling, initiating the vacuum pumping operation, in which the cooling includes providing a cooling relief effect selectively to a high-temperature stage of the refrigerator.