Pressure Transmitter Isolator System with Segmented Tubes
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Solution Overview
Problem
Existing isolator systems in pressure transmitters restrict the flow of oil, leading to slowed response times for pressure sensors due to narrow passageways, which limits the use of low isolator liquid volume without inhibiting rapid sensor response.
Innovation Solution
The isolator system allocates a majority of the cross-sectional area to the sensor tube, reducing flow impedance and allowing a smaller oil fill tube, enabling rapid pressure detection without increasing port size or oil volume, and combining the sensor and fill tubes into a single port to reduce manufacturing costs and liquid usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If narrow passageways are used in the isolator system, then the quantity of isolator liquid is reduced and thermal expansion effects are limited, but the flow of oil is restricted and the response time of the pressure sensor is slowed
Solution Approach 1:
The isolator system is divided into separate functional components: a fill tube for liquid charging and a sensor tube for pressure transmission. This segmentation allows the fill tube to be narrower (reducing liquid volume) while the sensor tube can be wider (improving response time), resolving the contradiction between minimizing liquid quantity and maintaining fast response.
Solution Approach 2:
Different parts of the isolator system are given different cross-sectional areas according to their specific functions. The fill tube has a smaller cross-sectional area optimized for minimizing liquid volume, while the sensor tube has a larger cross-sectional area optimized for rapid pressure transmission. This local differentiation resolves the contradiction by allowing each component to be optimized for its specific purpose.
2Quantity of substance
If the sensor tube has a small cross-sectional area, then the total isolator liquid volume is reduced, but the flow impedance increases and response time is slowed
Solution Approach 1:
The system separates the fill function from the sensor function into distinct tubes. The sensor tube is optimized with sufficient cross-sectional area for rapid response, while the fill tube is optimized for minimal liquid volume, eliminating the need to compromise sensor response time to reduce overall liquid volume.
Solution Approach 2:
The cross-sectional area parameter is differentiated between the fill tube and sensor tube. By allowing different cross-sectional area values for different components, the system achieves both low overall liquid volume and fast response time, resolving the contradiction between these two parameters.
3Ease of manufacture
If separate passages are used for the fill tube and sensor tube, then manufacturing and assembly are simplified, but the device complexity and port requirements increase
Solution Approach 1:
The fill tube and sensor tube are combined and passed through a single port in the transmitter body. This merging approach reduces the number of ports required, simplifies the overall device structure, and decreases complexity while maintaining the manufacturing advantages of having separate fill and sensor pathways.
Solution Approach 2:
The single port serves multiple functions by accommodating both the fill tube and sensor tube. This multi-functionality reduces the number of separate openings needed in the transmitter body, simplifying the device design and reducing complexity while preserving the benefits of separate tube functions.
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 ensures rapid pressure response without slowing sensor detection and reduces manufacturing costs and isolator liquid usage, while maintaining low liquid volume, thereby improving temperature performance and consistency.
Implementation Method 1
a relatively inert isolator liquid that couples pressure from a process fluid to a pressure sensor
Implementation Method 2
A flexible isolator diaphragm separates the process fluid from the isolator liquid
Implementation Method 3
limit the pressure effects due to thermal expansion and contraction of the oil
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An isolator system 14 for a pressure transmitter 10 includes a port 32 internal to the transmitter 10, a sensor tube 34, and a fill tube 36. The sensor tube 34 is connected to the port 32 to fluidly connect a passageway 28 through a transmitter body 12 to a pressure sensor 16. The sensor tube 34 includes a first end 40 disposed in the port 32. The first end 40 has a first cross-sectional area. The fill tube 36 is internal to the transmitter 10 and connected to the port 32 to fluidly connect to the passageway 28. The fill tube 36 includes a second end 42 disposed in the port 32. The second end 42 of the fill tube 36 has a second cross-sectional area that is less than the first cross-sectional area of the sensor tube 34.