Method and apparatus for improving the charge accuracy of a refrigerant recovery unit having a check valve device and temperature controlled service hoses
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Solution Overview
Problem
Current refrigerant recovery units face challenges in achieving accurate refrigerant charging due to fluctuations in ambient and system conditions, leading to undercharging or overcharging of refrigeration systems, which can result in system damage and decreased efficiency.
Innovation Solution
A refrigerant recovery unit with temperature-controlled service hoses and a recirculating circuit that purges vapor refrigerant before weight measurements, ensuring accurate refrigerant transfer and using a check valve assembly to maintain refrigerant in a liquid state during charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If refrigerant recovery units use standard service hoses without temperature control, then the device complexity is low, but the measurement precision of refrigerant weight is poor due to vapor condensation and ambient temperature fluctuations
Solution Approach 1:
The patent applies parameter changes by actively controlling the temperature of service hoses to maintain refrigerant in liquid state. Temperature sensors monitor hose temperature and heating elements adjust it dynamically, changing the thermal parameter to prevent vapor condensation and ensure accurate weight measurements during refrigerant charging.
Solution Approach 2:
The patent replaces manual temperature management with an automated electronic control system. The microcontroller-based system substitutes mechanical judgment and manual adjustment with electronic sensing and automatic heating control, improving measurement precision while managing the complexity through integration.
2Quantity of substance
If refrigerant is allowed to evaporate in service hoses during charging, then the operation is simpler without additional circuits, but the quantity of refrigerant transferred accurately is reduced due to vapor loss
Solution Approach 1:
The patent applies preliminary action by implementing a recirculating circuit that pre-cools service hoses and maintains refrigerant in liquid state before charging begins. The system circulates refrigerant through hoses beforehand to establish proper temperature conditions, ensuring accurate quantity transfer when charging starts.
Solution Approach 2:
The recirculating circuit enables continuous cooling of service hoses during the entire charging process. Rather than a single preparatory step, the system maintains continuous refrigerant circulation to keep hoses at optimal temperature throughout charging, ensuring consistent liquid state and accurate quantity transfer.
3Measurement precision
If check valve assembly provides free flow during recovery, then the productivity of refrigerant recovery is high, but the measurement precision during subsequent charging is poor without cracking pressure
Solution Approach 1:
The patent applies dynamics by making the check valve assembly dynamically adjustable with two distinct modes. During recovery, the valve provides free flow for high productivity. During charging, it applies cracking pressure to maintain liquid state for measurement precision. The system dynamically switches between these two operational states based on the process phase.
Solution Approach 2:
The check valve assembly applies local quality by creating different flow conditions in different operational phases. The valve structure provides free flow characteristics during recovery while switching to restricted flow with cracking pressure during charging. Each phase receives the specific flow quality it needs for optimal performance.
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 enhances the accuracy of refrigerant charging by ensuring precise weight measurements and maintaining refrigerant in a liquid state, thereby improving the efficiency and longevity of refrigeration systems.
Implementation Method 1
purges vapor refrigerant before weight measurements
Implementation Method 2
ensuring accurate refrigerant transfer
Implementation Method 3
temperature controlled service hoses... maintaining refrigerant in a liquid state during charging
Data Source
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AI summary
A refrigerant recovery unit with improved charging accuracy is provided. A service hose that includes a service coupler and a check valve A refrigerant recovery unit with improved charging accuracy is provided. A service hose includes a service coupler and a check valve assembly. The assembly is disposed proximal to the service coupler and includes a recovery flow and recharge flow path. The assembly is configured to provide a substantially free flow of refrigerant and also configured to provide a predetermined cracking pressure in response to the refrigerant being urged to flow along the recharge flow path. The disclosure includes thermally conditioning the interior of the service hoses based on one or more temperature reading(s) and/or based on a function and may be achieved by a heater along the length of the hose, recirculating refrigerant, and/or through a parallel line of heated liquid.