Semi-commanded Valve System for Compressor Capacity Modulation
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Solution Overview
Problem
Conventional reciprocating compressor valve systems are inflexible and non-customizable, requiring high energy for starting and operation, and lack efficient capacity modulation capabilities, especially in fixed-speed compressors, leading to energy inefficiencies and high costs.
Innovation Solution
A semi-commanded valve system utilizing prestressed mechanical valves and selectively actuated magnetic fields to control the operational state of suction and discharge valves, allowing for flexible modulation of valve opening and closing times to manage compressor capacity without varying motor speed, using electric coils to generate magnetic fields for valve control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional suction valves are used with normal closed configuration, then the valves can open automatically when pressure difference is sufficient, but high starting force is required for the motor and energy loss for pumping increases
Solution Approach 1:
The suction valve is prestressed in the opened position before operation, so that it remains open during the suction stroke without requiring high pressure differential to open. This preliminary positioning eliminates the need for high starting force and reduces pumping energy loss while maintaining reliable valve operation.
Solution Approach 2:
The valve system changes the operational parameter of the suction valve from normally closed to prestressed open position. This parameter change allows the valve to remain open during the suction stroke, reducing the pressure differential required and thereby reducing energy loss for pumping while maintaining reliable operation.
2Reliability
If conventional discharge valves are used with normal closed configuration, then the valves can open automatically when cylinder pressure exceeds discharge chamber pressure, but capacity modulation of the compressor is prevented
Solution Approach 1:
The discharge valve system transitions from a static normally-closed configuration to a dynamic semi-commanded system where the valve can be selectively actuated to remain open or close at different times during the compression cycle. This dynamic control enables capacity modulation while maintaining reliable valve operation when needed.
Solution Approach 2:
The discharge valve can be prestressed in the opened position before the compression cycle begins, allowing selective control of when the valve opens and closes. This preliminary positioning enables capacity modulation by controlling the timing of valve operation without compromising reliability when the valve is held in the appropriate position.
3Adaptability or versatility
If variable speed compressors are used for capacity modulation, then effectiveness gains can be obtained in systems demanding varying gas masses, but complex electronics and permanent-magnet motors with high costs are required
Solution Approach 1:
The patent replaces the complex variable speed motor-electronics system with a simpler fixed-speed motor combined with a semi-commanded valve system. The valve system uses magnetic actuators and prestressed springs to control valve timing, providing capacity modulation without requiring variable speed drives or complex electronics.
Solution Approach 2:
Instead of changing the motor speed parameter to modulate capacity, the invention changes the valve timing parameters (opening and closing times) while maintaining constant motor speed. This parameter substitution achieves capacity modulation with simpler fixed-speed motors and avoids complex variable speed electronics.
4Device complexity
If fixed speed compressors with ON-OFF control are used, then motor complexity is reduced, but capacity modulation capability is lost
Solution Approach 1:
The patent adds dynamic control capability to a fixed-speed compressor by implementing a semi-commanded valve system. The valves can be selectively actuated to open or close at different times during the compression cycle, providing continuous capacity modulation while the motor remains a simple fixed-speed type without complex electronics.
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
Enables efficient capacity modulation and reduced energy consumption by allowing selective control of valve states, facilitating better refrigeration system performance with reduced energy expenditure and lower costs compared to existing solutions.
Implementation Method 1
at least a selectively actuated magnetic field generating element... selectively actuated by generating a magnetic field with said at least a magnetic field generating element
Implementation Method 2
comprising at least a ferrous portion... selectively actuated by generating a magnetic field
Data Source
Figure 1
AI summary
Semi-commanded valve system applied to an alternative-type compressor, wherein said compressor comprises at least a cylinder (1), at least a piston (2), at least a compression chamber (3), and at least one valve (71;81) acting in their respective orifice (7;8). Said at least one valve (71;81) is prestressed in a first operation state and is able to act as a check valve. Furthermore, said at least one valve (71;81) comprises at least a ferrous portion and can be selectively actuated by a magnetic field generating element (72;82). Method of modulating the capacity of a compressor provided with such a semi-com¬ manded valve system.