Dry Pump Restart Failure Prevention via Pulsed Purging

Solution Overview

Problem

Dry pumps used in semiconductor manufacturing experience restart failures due to compacted particulate contaminants between components, which increase frictional forces beyond operational torque, as they cool and contract, leading to inefficient purge functions and frequent start-up failures.

Innovation Solution

Implementing an automated shutdown sequence with a controller and temperature sensor that initiates pulsed operation of the dry pump at pre-selected temperature intervals to purge contaminant particulate matter, reducing the amount of compacted contaminants and thus minimizing frictional forces during restart.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pump operates continuously to maintain productivity, then productivity is improved, but particulate contaminants compact between components causing restart failure

Engineering Contradiction:

Improvecontinuous operationVSAvoidrestart failure

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pump operates in periodic cycles rather than continuously. During each cycle, the pump runs for a predetermined time period to evacuate contaminants, then shuts down for a predetermined time period to allow cooling. This periodic operation pattern prevents contaminant compaction while maintaining productivity by ensuring the pump is ready for reliable restart.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The pump performs a preliminary purging operation before shutdown, evacuating contaminants from the pumping mechanism while still warm. This preliminary action prevents contaminants from compacting during the subsequent cooling period, ensuring smooth restart when the pump is reactivated.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If the pump shuts down completely to cool components, then temperature reduction is improved, but contaminants compact between components increasing friction

Engineering Contradiction:

ImprovecoolingVSAvoidfrictional force

Core Design Contradiction:

TemperatureVSForce

Solution Approach 1:

The pump performs a preliminary purging operation before shutdown, evacuating contaminants from the pumping mechanism while still warm. This preliminary action prevents contaminants from compacting during the subsequent cooling period, ensuring smooth restart when the pump is reactivated.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pump operates in periodic cycles rather than continuously. During each cycle, the pump runs for a predetermined time period to evacuate contaminants, then shuts down for a predetermined time period to allow cooling. This periodic operation pattern prevents contaminant compaction while maintaining productivity by ensuring the pump is ready for reliable restart.

Inventive Principle:

Principle #19Periodic action

3Reliability

If the pump runs at high torque to overcome friction on restart, then reliability is improved, but energy consumption increases

Engineering Contradiction:

Improverestart successVSAvoidtorque requirement

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The pump performs a preliminary purging operation before shutdown, evacuating contaminants from the pumping mechanism while still warm. This preliminary action prevents contaminants from compacting during the subsequent cooling period, ensuring smooth restart when the pump is reactivated.

Inventive Principle:

Principle #10Preliminary action

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

Significantly reduces the occurrence of restart failures by effectively evacuating particulate contaminants during cooling, ensuring smoother pump operation and reducing the torque required for start-up.

Implementation Method 1

a sensor for sensing the operating temperature of the pumping mechanism

Methodology Applied

Scientific EffectTemperature sensing: Thermal Radiation

Implementation Method 2

initiating operation of the pumping mechanism for a fixed time period so as to purge a proportion of contaminant particulate matter present

Methodology Applied

Scientific EffectPulsed purging: Pulse Jet

Implementation Method 3

when the pumps are switched off, they cool to normal room temperature, the components (such as rotors and stators in the pump mechanism) contract, reducing the running clearances between them

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 4

the torque required to overcome the friction caused by the presence of these particulate materials compacted between the components is higher than the operational torque of the pump

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8398376B2Dry pumps

Publication Date: 2013.03.19 EDWARDS LTD

AI summary

A dry pump apparatus comprises; a pumping mechanism, a controller for controlling the operation of the pumping mechanism, and a sensor for sensing the operating temperature of the pumping mechanism. The controller is configured to carry out an automated shutdown sequence involving the following steps; a) ceasing operation of the pumping mechanism b) monitoring the temperature of the pumping mechanism by means of the temperature sensor c) at least one pre-selected temperature interval, initiating operation of the pumping mechanism for a fixed time period so as to purge a proportion of contaminant particulate matter present until a predefined temperature is reached or a predefined time limit has passed. By carrying out these steps the incidence of powder compaction between component parts of the apparatus which may contract during shutdown, and consequential restart failure and down time, can be significantly reduced.