Process Valve Force Measurement via Spring Deflection
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Solution Overview
Problem
Existing force measurement methods in process valves are costly due to high current consumption and require sophisticated electronics, which is problematic in potentially explosive environments, and are prone to distortion from friction forces and inertia in pneumatic drives.
Innovation Solution
A force measuring device using a spring and travel measuring device to determine force through spring deflection, with mechanical amplification and anisotropic magnetoresistive sensors, eliminating the need for high-current electronics and providing accurate, fast measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain gauge is used to measure force in the valve rod, then force measurement is achieved, but the device becomes costly and consumes high current due to the need for sophisticated electronic amplifiers
Solution Approach 1:
The patent replaces the electrical strain gauge measurement system with a mechanical spring-based measurement system. The spring constant provides a direct mechanical relationship between force and displacement, eliminating the need for electrical amplifiers and associated high current consumption while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces a spring as an intermediary element between the valve rod and the measurement system. This spring translates the force applied to the valve rod into a measurable displacement, serving as a mechanical mediator that converts force into a readable output without requiring complex electronics.
2Measurement precision
If driving pressure in a pneumatic drive is measured to determine force, then force information is obtained, but the measurement is distorted by friction forces and cannot detect fast peak pressures
Solution Approach 1:
The patent extracts the force measurement function from the pneumatic drive system itself and places it directly in the valve rod through the spring mechanism. This separation eliminates the distorting influence of friction forces within the pneumatic drive and allows direct measurement of the actual force applied to the valve body, including fast peak pressures.
3Use of energy by moving object
If a spring-based force measuring device is used, then low current consumption and fast response are achieved, but the spring deflection is too small to measure accurately without amplification
Solution Approach 1:
The patent transforms the small linear spring deflection into a larger rotational movement through a lever mechanism. This dimensional transformation from linear to rotational motion amplifies the measurement signal, making the small spring deflections easily measurable while maintaining the low current consumption benefits of the spring-based system.
4Measurement precision
If mechanical amplification is used to increase measurement accuracy, then measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent designs the lever mechanism to serve multiple functions: it provides mechanical amplification for accurate measurement, transmits the spring force to the indicator, and can be integrated into the existing valve structure. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity despite the addition of mechanical amplification.
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 reliable, low-power force measurement in process valves with high accuracy and quick response, avoiding the limitations of prior methods by using mechanical amplification and AMR sensors, suitable for use in explosive environments.
Implementation Method 1
a spring (30) which is elastically deformable
Implementation Method 2
the travel measuring device (38, 42) is designed as an AMR sensor and magnet in such a way that a change of travel of the magnet (42) with respect to the sensor (38) will result in a vast change of direction of the field strength of the magnet at the site of the sensor (38)
Data Source
AI summary
The invention relates to a process valve (10) comprising a valve seat (14), a flow restrictor (12), a valve rod (16) and a drive unit (18) acting thereon, with a force measuring device (20, 44) being connected between said drive unit (18) and said flow restrictor (12). The invention is characterized in that said force measuring device (49) includes a spring (30, 46), and said force measuring device (29, 44) comprises a travel measuring device (38, 42, 50, 52) so as to allow the force acting on it to be determined based on the change in the deflection of the spring (30, 46) caused by the force acting on it.