Vacuum Pump Temperature Sensor Purge Gas Flow Control
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Solution Overview
Problem
Existing vacuum pump systems face challenges in accurately measuring the temperature of rotating portions at high speeds due to low gas flow rates and pressure, leading to increased measurement errors and high costs associated with continuous purge gas supply.
Innovation Solution
The system incorporates a throttle portion and thread groove-type seal in the purge gas flow path to control the flow velocity and pressure around the temperature sensor, ensuring an intermediate or viscous flow, thereby reducing measurement errors and the amount of purge gas required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large amount of purge gas is supplied to maintain viscous flow around the temperature sensor, then heat transfer improves and measurement accuracy increases, but gas consumption increases and cost increases
Solution Approach 1:
The patent changes the flow regime parameter from molecular flow to viscous flow by optimizing the purge gas flow rate. By controlling the flow rate to achieve viscous flow (Reynolds number between 2000-10000), the system obtains sufficient heat transfer for accurate temperature measurement while avoiding excessive gas consumption. This parameter optimization allows the system to operate efficiently without requiring large amounts of purge gas continuously.
Solution Approach 2:
The patent implements periodic supply of purge gas rather than continuous supply. The purge gas is supplied periodically to maintain viscous flow conditions during temperature measurement, then stopped or reduced when measurement is not needed. This periodic action significantly reduces overall gas consumption while maintaining measurement accuracy when required.
2Measurement precision
If the purge gas flow rate is increased to prevent process gas from reaching the temperature sensor, then measurement accuracy improves, but the cost of purge gas supply increases
Solution Approach 1:
The patent optimizes the purge gas flow rate parameter to achieve the minimum necessary flow for preventing process gas contamination. By calculating and controlling the flow rate to maintain viscous flow conditions (Reynolds number between 2000-10000), the system uses the minimum effective amount of purge gas, reducing both cost and system complexity while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces complex mechanical flow control systems with a simpler periodic supply mechanism. Instead of using complex valves and flow controllers to continuously regulate purge gas flow, the system uses a simpler periodic supply approach that achieves the same goal of maintaining appropriate flow conditions during measurement, thereby reducing system complexity and cost.
3Measurement precision
If continuous purge gas supply is maintained to ensure intermediate or viscous flow, then heat transfer efficiency improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic supply of purge gas rather than continuous supply. The purge gas is supplied periodically to maintain viscous flow conditions during temperature measurement, then stopped or reduced when measurement is not needed. This periodic action significantly reduces overall energy consumption while maintaining measurement accuracy when required.
Solution Approach 2:
The patent optimizes the purge gas flow rate parameter to achieve the minimum necessary flow for maintaining viscous flow conditions. By controlling the flow rate to achieve Reynolds number between 2000-10000, the system uses the minimum effective amount of purge gas, reducing energy consumption while maintaining sufficient heat transfer for accurate temperature measurement.
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 configuration allows for accurate temperature measurement of the rotating portion while minimizing the amount of purge gas used, reducing costs and preventing measurement errors caused by gas composition changes and low heat transfer.
Implementation Method 1
the pressure of the gas around the temperature sensor unit creates an intermediate flow or a viscous flow
Implementation Method 2
transmission of an insufficient amount of heat and increased measurement errors of the temperature sensors
Implementation Method 3
the throttle portion controlling the purge gas flow path in one direction
Implementation Method 4
the temperature of a rotating portion needs to be measured using a non-contact type temperature sensor
Implementation Method 5
Japanese Patent Application Publication No. H11-37087 describes a technique that increases the radiation rates of both the rotor blades to be measured and heat receiving portions of the temperature sensors
Data Source
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AI summary
The present invention provides a vacuum pump that measures the temperature of a rotating portion accurately and at low cost, a stator column of the vacuum pump, a base, and an exhaust system of the vacuum pump at low cost. The vacuum pump according to the present embodiment, the thread groove-type seal for causing some of the purge gas to flow back toward the temperature sensor unit is provided on the downstream side of the purge gas flow path in which the temperature sensor unit is disposed, thereby increasing the pressure of the purge gas in the vicinity of the temperature sensor unit. Thus, with the small amount of purge gas, the gas pressure around the temperature sensor unit can create an intermediate flow or a viscous flow. Consequently, the total amount of purge gas to be supplied can be saved, resulting in cost reduction.