Cyclic Liquid Fuel Metering With Diaphragm Pumps and Level Feedback
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Solution Overview
Problem
Liquid fuel fireplaces face issues with unstable fuel supply and short service life due to aging rubber tubes in constant displacement pumps, leading to inconsistent combustion and high maintenance costs.
Innovation Solution
A device utilizing diaphragm pumps with cyclic operation, including a constant amount chamber, liquid level detection, and a controller to maintain a consistent liquid volume between high and low levels, along with orifice plugs to stabilize flow rates and an overflow system for pressure balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant displacement pump with rubber tube is used to supply liquid fuel, then a stable supply rate can be achieved initially, but the rubber tube ages due to cyclic stress over time, resulting in reduced flow rate and unstable combustion
Solution Approach 1:
The patent replaces the expensive constant displacement pump with inexpensive diaphragm pumps that can be easily replaced. Instead of designing for long service life of a single pump component, the system uses affordable pumps that maintain reliability through periodic replacement, solving the contradiction between initial stability and long-term durability
Solution Approach 2:
The system implements periodic operation where diaphragm pumps operate in cycles rather than continuously. The controller activates pumps intermittently to deliver precise liquid volumes, allowing mechanical components to rest and reducing cumulative stress, thereby extending service life while maintaining supply stability
2Reliability
If a constant displacement pump is used to ensure stable liquid fuel supply, then combustion stability can be achieved, but the system becomes expensive and troublesome to maintain
Solution Approach 1:
The patent substitutes expensive constant displacement pumps with inexpensive diaphragm pumps that are widely available and easy to replace. The low cost and simplicity of these pumps dramatically reduce maintenance burden while the controller ensures they deliver consistent liquid volumes, maintaining combustion stability
Solution Approach 2:
The system incorporates automatic control that monitors liquid levels and pump operation, eliminating the need for manual intervention or complex maintenance procedures. The controller automatically manages pump activation and liquid level compensation, making the system self-regulating and easy to maintain
3Ease of manufacture
If diaphragm pumps are used instead of constant displacement pumps, then cost and simplicity are improved, but the pumps naturally have unstable flow rates that must be controlled
Solution Approach 1:
The patent implements a feedback control system where liquid level detection probes monitor the liquid level in the constant amount chamber and provide signals to the controller. The controller adjusts pump operation based on this feedback, ensuring that the correct liquid volume is delivered each cycle, thereby achieving flow rate consistency despite using simple diaphragm pumps
Solution Approach 2:
The system pre-fills the constant amount chamber with a specific volume of liquid before each dispensing cycle. This preliminary action ensures that the chamber contains the exact amount needed, and the controller manages dispensing to maintain consistent flow rates throughout operation, resolving the instability issue of diaphragm pumps
Data Source
AI summary
Disclosed are a device for supplying liquid at a constant amount and a method for controlling the same, and the device for supplying liquid at a constant amount comprises a constant amount chamber, an input pump, an output pump, a liquid level detection device, and a controller; the input pump is provided with an input pump liquid feeding pipe and an input pump liquid discharging pipe; the output pump is provided with an output pump liquid feeding pipe and an output pump liquid discharging pipe; the input pump, the output pump, and the liquid level detection device are each in matched connection with the controller. In the present invention, by cyclic operation, a liquid volume between a high liquid level and a low liquid level is delivered at a constant amount in each cycle, so that liquid fuel is supplied at a constant amount.