Temperature control device and process control apparatus including a temperature control device
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Solution Overview
Problem
Process control field devices are often affected by extreme temperature variations, as their components are designed for moderate environments and protective housings are not effective in preventing temperature-related issues.
Innovation Solution
A temperature control device using a vortex tube and flow control valve to regulate the internal atmosphere of a housing, with a temperature sensing feature that adjusts the flow of hot and cold air streams to maintain optimal conditions, utilizing a compressed fluid to separate into distinct temperature streams and a control element to direct airflow accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If protective housings are used to enclose process control devices, then mechanical protection is improved, but temperature control effectiveness deteriorates
Solution Approach 1:
The housing is segmented into an outer housing and an inner temperature-controlled housing, creating separate thermal zones. The temperature-controlled housing can be selectively positioned relative to the outer housing to provide thermal protection while maintaining mechanical protection from the outer housing.
Solution Approach 2:
A temperature-controlled atmosphere is introduced as an intermediary medium between the external extreme temperature environment and the process control devices. This intermediate thermal environment protects the devices from direct exposure to extreme temperatures while allowing mechanical protection to remain intact.
2Temperature
If conventional refrigeration systems are used for temperature control, then cooling capability is improved, but device complexity and cost deteriorate
Solution Approach 1:
The system uses the process control device's own waste heat and the ambient temperature differential to drive the temperature control. The heated atmosphere from process devices is redirected to preheat incoming air or provide heat to other zones, eliminating the need for external heating sources and reducing overall system complexity.
Solution Approach 2:
The system uses pneumatic actuators and fluid-based temperature sensing/control mechanisms to regulate the temperature-controlled atmosphere. This approach provides precise control without requiring complex mechanical refrigeration components, maintaining simplicity while achieving effective temperature management.
3Use of energy by moving object
If heated atmosphere is used to preheat incoming air, then energy efficiency is improved, but temperature control precision deteriorates
Solution Approach 1:
Temperature sensors continuously monitor the temperature within the temperature-controlled housing and provide feedback to the control system. This feedback mechanism allows the system to adjust the heated atmosphere flow and preheating rate to maintain precise temperature control while maximizing energy efficiency through optimal heat recovery.
Solution Approach 2:
The system dynamically adjusts the balance between direct heating and preheating operations based on real-time temperature conditions and energy availability. The heated atmosphere flow rate and preheating intensity are continuously optimized to maintain temperature precision while maximizing energy efficiency under varying operating conditions.
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
Effectively manages temperature within a process control apparatus to ensure operational usability across extreme temperature conditions, from -100 °C to 200 °C, by selectively directing hot and cold air streams based on internal temperature sensing, thus protecting the devices from extreme temperatures.
Implementation Method 1
The temperature controlled air supply system comprises a source of ram air (a scoop). Connected to air scoop is a centrifugal type separator or vortex tube which separates the air stream entering the air scoop into two portions or air streams, one of which is at high temperature, while the other is at low temperature.
Implementation Method 2
The temperature sensing feature can include a reservoir of a control fluid that expands in response to an increase in the temperature of the atmosphere internal to the housing and contracts in response to a decrease in the temperature of the atmosphere internal to the housing.
Data Source
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AI summary
A process control apparatus includes a housing, a process control device disposed in the housing, and a temperature control device operably coupled to the housing for regulating a temperature of an atmosphere internal to the housing. The temperature control device includes a vortex tube and a flow control valve. The flow control valve is coupled to the vortex tube and includes a temperature sensing feature configured to sense a temperature of an atmosphere internal to the housing and configured to move a control element of the flow control valve based on the sensed temperature between a plurality of positions to selectively direct the flow of fluid from the first and second vortex outlets to the atmosphere internal to the housing.