Perpendicular Aperture Sensing Tube for Accurate Pressure Registration
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Solution Overview
Problem
Conventional gas regulators face inaccuracies in pressure measurement due to the creation of low pressure zones at the sensing tube ends, leading to inaccurate registration of downstream pressure, especially with variations in flow velocities and demand.
Innovation Solution
The design incorporates a sensing tube with apertures perpendicular to the flow axis, eliminating the low pressure zone by normalizing the pressure communicated to the control cavity, ensuring accurate pressure registration regardless of flow changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an internal sense tube extends from the control cavity to the outlet of the regulator valve to sense downstream pressure, then the pressure can be sensed internally without external control lines, but a low pressure zone is created at the open terminal end of the sense tube due to flow velocities, resulting in inaccurate pressure registration
Solution Approach 1:
The sensing tube is oriented perpendicular to the flow direction, changing the dimensional approach from axial sensing (parallel to flow) to radial sensing (perpendicular to flow). This dimensional change allows the sensing aperture to be positioned in a location不受 flow velocity effects, eliminating the low pressure zone problem while maintaining internal sensing capability
Solution Approach 2:
The patent uses a simplified internal sense tube structure that copies the essential function of external control lines but eliminates their complexity. The sense tube provides the same pressure sensing function internally integrated into the regulator body, achieving both simplicity and accuracy through proper geometric design
2Ease of manufacture
If the sense tube extends parallel to the flow direction or obliquely into the outlet, then installation is simplified, but the registered pressure varies with flow rate changes, negatively impacting overpressure protection capability
Solution Approach 1:
The sensing tube is oriented perpendicular to the flow direction, changing the dimensional approach from axial sensing (parallel to flow) to radial sensing (perpendicular to flow). This dimensional change allows the sensing aperture to be positioned where it is not affected by flow velocity, eliminating the low pressure zone problem while maintaining internal sensing capability
Solution Approach 2:
The patent changes the geometric parameters of the sensing tube configuration, specifically the orientation angle relative to flow direction. By setting the angle at 90 degrees (perpendicular), the sensing location parameter is optimized to be independent of flow velocity variations, ensuring consistent pressure registration across different flow conditions
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 configuration provides accurate pressure measurement and control, enhancing the reliability of overpressure protection devices by maintaining consistent pressure registration across varying flow conditions.
Implementation Method 1
A sensing tube has a first end in fluid communication with the outlet and a second end in fluid communication with the control cavity such that the control cavity is in fluid communication with the outlet through the sensing tube. A first portion of the sensing tube extends along a tube axis that is parallel to a vertical flow axis. One or more apertures are disposed in the sensing tube adjacent to the first end, and each of the one more apertures has a centerline that is perpendicular to the tube axis and the flow axis. So configured, pressure in the outlet is communicated to the control cavity through the sensing tube, thereby eliminating the need for an external control line to accurately communicate pressure in the outlet to the control cavity.
Data Source
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AI summary
A fluid regulating device includes a regulator valve (12) having an inlet (14), an outlet (16), and a valve port (18) disposed between the inlet (14) and the outlet (16). An actuator (20) is coupled to the regulator valve (12) and includes a valve disc (22) that displaces between a closed position and an open position. The device also includes an overpressure protection device (25) adapted to stop flow from the inlet to the outlet when pressure in a control cavity reaches a predetermined level. The overpressure protection device (25) includes a sensing tube (28) having a first end (29) in fluid communication with the control cavity (27) and a second end (30) in fluid communication with the outlet (16). The sensing tube (28) has a first portion extending parallel to the flow axis. One or more apertures (34) are disposed in the sensing tube (28) adjacent to the second end (30), and each of the apertures (34) has a centerline that is perpendicular to the flow axis.