Flow control valve for injecting oil into an air conditioning circuit
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Solution Overview
Problem
Current air conditioning service machines lack precision in measuring and injecting the correct quantity of compressor oil due to reliance on visual identification, operator error, and variability in oil flow rates affected by viscosity and temperature, leading to inefficiencies and inaccuracies.
Innovation Solution
The implementation of a flow control valve with a plunger and biasing member that maintains a constant oil flow rate independent of viscosity, ensuring accurate oil injection by regulating the flow based on pressure differences and geometry of the valve components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If visual identification method is used to measure oil injection quantity, then cost is minimized, but measurement precision deteriorates due to operator error and inaccuracy in reading markings
Solution Approach 1:
The patent replaces the visual identification method with a flow control valve system that uses pressure differential and geometric parameters to control oil flow rate. This mechanical substitution eliminates operator error in reading markings while maintaining cost-effectiveness by avoiding expensive load cells or electronic sensors.
Solution Approach 2:
The flow control valve enables the system to self-regulate oil injection quantity through its inherent pressure-flow characteristics. The valve automatically adjusts flow rate based on pressure differential across the valve and its geometric parameters, eliminating the need for continuous operator intervention or complex measurement systems.
2Device complexity
If time-based oil injection method is used, then device complexity is reduced, but measurement precision deteriorates due to variability in oil flow rate caused by viscosity and temperature changes
Solution Approach 1:
The patent changes the controlling parameters from time-based injection to pressure differential and geometric parameter-based flow control. By using the relationship between pressure difference, valve geometry, and flow rate, the system compensates for viscosity and temperature variations without adding complex sensors or control mechanisms.
Solution Approach 2:
The patent utilizes hydraulic principles by employing a flow control valve that leverages pressure differential and fluid dynamics to regulate oil flow rate. This approach uses the inherent properties of the oil-fluid system itself to achieve precise control, avoiding the need for electronic sensors or complex mechanical measurement devices.
3Measurement precision
If load cell is used to measure oil bottle weight, then measurement precision is improved, but device complexity and cost increase due to expensive and delicate components
Solution Approach 1:
The patent extracts the measurement function from the oil bottle weighing system and replaces it with a flow control valve that directly controls and determines oil flow rate. This eliminates the need for load cells and associated weighing mechanisms, simplifying the system while maintaining measurement precision through flow-based control.
Solution Approach 2:
The patent replaces expensive, delicate load cells with a simpler, more robust flow control valve mechanism. The flow control valve is a durable mechanical component that can tolerate rough handling and environmental conditions, providing a cost-effective and reliable alternative to sensitive weighing systems.
4Measurement precision
If flow control valve with pressure differential control is used, then measurement precision is improved by maintaining constant flow rate independent of viscosity, but device complexity increases due to additional valve components
Solution Approach 1:
The flow control valve performs multiple functions: it controls oil flow rate, compensates for viscosity variations, and provides a reference flow rate for injection quantity determination. By integrating these functions into a single valve component, the patent achieves precise measurement without proportionally increasing system complexity.
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 provides precise and accurate oil injection, minimizing user intervention and reducing costs by maintaining consistent flow rates regardless of oil viscosity, thereby enhancing the operational efficiency of air conditioning systems.
Implementation Method 1
The flow control valve is configured such that, for a given pressure difference between the inlet and the outlet, the oil flows from through the flow control valve at a flow rate that is independent of a viscosity of the oil
Data Source
AI summary
An air conditioning service system includes an oil receptacle configured to store an oil, a solenoid valve configured to selectively allow the oil to flow from the oil receptacle into an oil injection line, a coupling port in fluid communication with the oil receptacle through the oil injection line when the solenoid valve is in an open condition, and a flow control valve with an inlet and an outlet. The inlet is in fluid communication with the oil receptacle when the solenoid valve is in the open condition, and the outlet in fluid communication with the oil injection line when the solenoid valve is in the open condition. The flow control valve is configured such that, for a given pressure difference between the inlet and the outlet, the oil flows from through the flow control valve at a flow rate that is independent of a viscosity of the oil.