Dome-loaded back pressure regulator with setpoint pressure energized by process fluid
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Solution Overview
Problem
Existing pressure regulation systems in refrigeration systems, particularly in heat exchangers, face challenges in controlling refrigerant pressure rapidly and efficiently without requiring an external gas supply, leading to inefficiencies and risks of liquid ingestion by compressors due to inadequate control over small fluctuating loads and high valve authority requirements.
Innovation Solution
A self-contained back pressure control apparatus using a dome-loaded diaphragm pressure regulator controlled by a pilot pressure regulator, where the setpoint pressure is maintained using refrigerant tapped from the fluid loop upstream of the main pressure regulator, allowing for rapid and precise pressure control without external gas supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional linear control valves are used for back pressure regulation, then the system is economical and effective, but the response time is slow (10-30 minutes to stabilize)
Solution Approach 1:
The patent replaces traditional linear control valves with a dome-loaded back pressure regulator that uses direct diaphragm sealing and mechanical force balance. This mechanical system responds in less than 1 second by utilizing the native mechanical force balance of the diaphragm, eliminating the slow 10-30 minute stabilization time of linear valves while maintaining effectiveness.
Solution Approach 2:
The invention changes the operating parameters by using a dome-loaded design with direct diaphragm sealing that operates on mechanical force balance rather than linear valve mechanics. This parameter change enables response times under 1 second compared to the 10-30 minute response of traditional linear valves.
2Speed
If dome-loaded back pressure regulators with external gas supply are used, then rapid pressure control is achieved, but the system requires external gas supplies which complicates installation and operation
Solution Approach 1:
The patent implements a self-contained dome-loaded back pressure regulator that uses its own process fluid for dome loading rather than requiring external gas supplies like nitrogen or air. The regulator taps process fluid from the line upstream and returns it downstream, making the system self-sufficient and eliminating the need for external gas infrastructure.
Solution Approach 2:
The invention merges the process fluid circulation with the dome loading function by tapping fluid from the process line upstream of the regulator and returning it downstream. This combines the pressure control function with the existing process fluid flow, eliminating the need for separate gas supply systems.
3Stability of the object's composition
If traditional valves with high valve authority are used, then system stability is improved, but additional Joules-Thompson cooling condenses process fluid and reduces system efficiency
Solution Approach 1:
The patent changes the valve authority parameter by using a dome-loaded design with direct diaphragm sealing that requires minimal pressure drop to operate. This reduces the Joules-Thompson cooling effect that occurs in traditional high authority valves, preventing unwanted condensation of process fluid and improving system efficiency while maintaining stability.
4Reliability
If TXV is controlled with significant superheat to ensure vapor at compressor inlet, then compressor safety is improved, but evaporator and system efficiency decrease
Solution Approach 1:
The patent implements feedback control by using a dome-loaded back pressure regulator that continuously monitors and adjusts the back pressure to maintain the desired pressure differential across the evaporator. This feedback mechanism ensures vapor quality at the compressor inlet while operating close to the vapor dome, maximizing evaporator efficiency without compromising compressor safety.
Solution Approach 2:
The invention changes the control parameter from superheat-based control to back-pressure-based control. By regulating the back pressure downstream of the evaporator, the system can maintain vapor quality at the compressor inlet while operating with minimal superheat, thereby improving evaporator efficiency while ensuring compressor safety.
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 solution enables rapid and precise control of refrigerant pressure, reducing system inefficiencies and minimizing the risk of liquid ingestion, while eliminating the need for external gas supplies, thereby enhancing system stability and efficiency.
Implementation Method 1
a dome-loaded back pressure regulator controlled by a setpoint pressure
Implementation Method 2
This additional valve authority required by some traditional designs also can cause problems, since the large Joules-Thompson cooling could condense process fluid
Data Source
AI summary
A method of operating a thermal system including at least a compressor, a condenser, a flow control valve, and at least one heat exchanger connected in a closed fluid loop charged with refrigerant. The method includes: regulating refrigerant pressure at a selected point within the fluid loop using a pressure regulating apparatus including: a main pressure regulator including a dome in fluid communication with a diaphragm that seals directly against at least one process void and at least one vent void; and a pilot pressure regulator in fluid communication with the dome so as to provide fluid thereto at a setpoint pressure. The setpoint pressure is maintained by the pilot pressure regulator utilizing refrigerant tapped from the fluid loop The refrigerant is tapped from a point upstream of the main pressure regulator and tapped refrigerant is returned to the fluid loop downstream of the main pressure regulator.