Gas Valve Unit With Segmented Flow Ports For Low-Capacity Control
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Solution Overview
Problem
Existing gas valves in multistage furnaces are unable to controllably maintain low-capacity gas flow rates within a desired tolerance, limiting their utilization at low capacity levels.
Innovation Solution
A valve unit with a movable closure member and solenoid system that selectively establishes high-capacity or low-capacity gas flow rates through a combination of first and second opening ports, controlled by a coil and solenoid or stepper-motor mechanism, allowing precise adjustment of gas flow rates based on input signals from a thermostat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gas valve is designed to operate at low capacity gas flow rates (as low as 30 percent of full capacity), then the furnace can provide increased performance and comfort by varying heating output, but the gas valve is not capable of controllably maintaining the gas flow rate within a desired tolerance
Solution Approach 1:
The gas valve is segmented into two distinct flow paths: a first opening port for high-capacity gas flow and a second opening port for low-capacity gas flow. A closure member selectively blocks the first opening port to direct gas flow through the smaller second opening port, enabling reliable low-capacity operation by isolating the gas flow control to a single, appropriately sized passage.
2Device complexity
If a gas valve uses a single opening port for all capacity levels, then the structure is simple, but it cannot maintain desired gas flow rate tolerance at low capacity levels
Solution Approach 1:
The single opening port is divided into two separate opening ports with different sizes. The first opening port handles high-capacity flow while the second opening port handles low-capacity flow. This segmentation allows each port to be optimized for its specific flow range, achieving precise flow rate tolerance at low capacities without excessive complexity.
Solution Approach 2:
A closure member acts as an intermediary that selectively blocks the first opening port when low-capacity operation is required. This intermediary component enables the system to transition between different flow paths, ensuring that gas flow passes through the appropriately sized second opening port for precise low-capacity control.
3Reliability
If a closure member is added to selectively block the first opening port for low-capacity operation, then reliable low-capacity gas flow control is achieved, but the device complexity increases
Solution Approach 1:
The closure member is actuated by a solenoid that responds to control signals from the furnace control system. The system automatically selects the appropriate opening port based on the required capacity level, with the closure member self-actuating to block the first opening port when low-capacity operation is needed, reducing the need for complex external control mechanisms.
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 consistent low-capacity gas flow rates within a desired tolerance range and high-capacity gas flow rates, improving the control and efficiency of gas-fired heating systems.
Implementation Method 1
a solenoid for selectively moving the closure member between the open and closed positions to respectively selectively establish a high-capacity gas flow rate or low capacity gas flow rate
Implementation Method 2
the coil is a solenoid coil that is configured to move the valve member to vary the high-capacity gas flow rate based on the magnetic field generated by the coil, where the magnetic field is dependent on the input voltage
Data Source
AI summary
A valve unit for adjusting gas flow to a combustion apparatus includes a valve member that moves relative to a valve seat in response to a signal input to a coil, for varying a high-capacity gas flow rate through the valve unit. The valve unit includes a first opening port, a second opening port that is smaller than the first opening port, and a closure member. The closure member is movable between an open position, in which said high-capacity gas flow rate is communicated via the first and second opening ports to an outlet, and a closed position against the first opening port, in which a low-capacity gas flow rate is communicated via only the second opening port to the outlet. The valve unit includes a solenoid for selectively moving the closure member between the open position and closed position to selectively establish a high-capacity gas flow rate or low capacity gas flow rate.