Radar Level Gauge HTHP Seal Design

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Solution Overview

Problem

Conventional radar level gauges face issues with sealing degradation due to soft dielectric filling members moving at varying temperatures and susceptibility to aggressive chemicals, leading to imperfect tank sealing and signal transmission deterioration.

Innovation Solution

A radar level gauge design featuring a dielectric filling member with an annular collar portion sandwiched between a clamping member and an annular abutment, secured by a fastening member and spring member, providing a pressure-tight seal without additional sealing elements like O-rings, and using a structurally strong outer dielectric filling member to maintain sealing at elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a soft dielectric filling member (e.g., PTFE) is used to prevent tank content entry, then the material is hydrophobic and has suitable dielectric properties, but the filling member moves and deforms at elevated temperatures, degrading the sealing

Engineering Contradiction:
Improvesealing reliabilityVSAvoidposition stability of filling member
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies a controlled pressure (parameter change) to the annular collar portion of the dielectric filling member through a spring member and clamping mechanism. This pressure prevents the filling member from moving or deforming at elevated temperatures, maintaining sealing reliability while preserving the beneficial properties of soft materials like PTFE.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies a preliminary counteracting force (pressure) to the dielectric filling member before temperature-induced movement occurs. The spring member and clamping mechanism pre-compress the annular collar portion, creating a force that opposes and prevents thermal deformation and movement, thereby maintaining sealing integrity.

Inventive Principle:
Principle #9Preliminary anti-action

2Ease of manufacture

If conventional sealing elements like O-rings are used, then the sealing is simple to implement, but the sealing elements are susceptible to deterioration from aggressive chemicals

Engineering Contradiction:
Improvesealing implementation simplicityVSAvoidchemical resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the functional role of the dielectric filling member from merely preventing tank content entry to also providing the sealing function. By applying controlled pressure to the annular collar portion, the filling member becomes chemically resistant while maintaining sealing simplicity, eliminating the need for separate O-rings that would be vulnerable to chemical deterioration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the dielectric filling member multi-functional: it prevents tank content entry, provides hydrophobic protection, maintains dielectric properties, and now also provides chemical-resistant sealing. This eliminates the need for separate sealing elements and improves overall system reliability in chemically aggressive environments.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If additional sealing elements like O-rings are added to improve sealing, then the sealing reliability improves, but the device complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the dielectric filling member multi-functional by enabling it to provide both tank content prevention and sealing functions simultaneously. The annular collar portion, when pressurized, creates an effective seal without requiring additional sealing elements, thereby maintaining simplicity while improving sealing reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the sealing function with the dielectric filling member structure. Instead of having separate components for preventing tank content entry and providing sealing, the patent combines these functions into a single integrated solution, reducing device complexity while maintaining or improving sealing performance.

Inventive Principle:
Principle #5Merging (Combining)

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

The design effectively withstands high pressures and temperatures, ensuring reliable tank sealing and maintaining signal transmission integrity by using a pressurized annular collar portion and a temperature-resistant outer filling member, reducing leakage and moisture ingress.

Implementation Method 1

a spring member arranged between the fastening member and the clamping member, and configured to press the clamping member towards the annular abutment, so as to apply a controlled pressure on the annular collar portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a dielectric filling member arranged in the tank connection and configured to prevent entry of tank content into the antenna and/or hollow wave guide

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

a transceiver for transmitting an electromagnetic transmit signal and receiving an electromagnetic echo signal, a directional antenna for directing the electromagnetic transmit signal towards a surface of the product and to return a reflection from the surface as the electromagnetic echo signal

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Data Source

PatentEP3529569B1Radar level gauge with high temperature, high pressure (HTHP) process seal
Publication Date: 2022.05.04 ROSEMOUNT TANK RADAR
  • EP3529569B1 patent drawingFigure 1
  • EP3529569B1 patent drawingFigure 2
  • EP3529569B1 patent drawingFigure 3

AI summary

A radar level gauge comprising a directional antenna (11), a hollow wave guide (20) connected to the antenna, a tank connection (21) having a through hole with an annular abutment (52), a dielectric filling member (31) arranged in the tank connection, the dielectric filling member comprising an annular collar portion (33) resting against the annular abutment (52), a clamping member (38) inserted into the tank connection, a fastening member (43) attached to the fixed tank connection to secure the clamping member between the fastening member and the annular abutment, and a spring member (51) arranged between the fastening member and the clamping member. The spring member presses the clamping member towards the annular abutment, to apply a controlled pressure on the annular collar portion, allowing the annular collar portion to serve as a pressure tight sealing between a tank interior and a tank exterior.