Vibrated Ceramic Sensor Encapsulation Method
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Solution Overview
Problem
Existing methods for encapsulating temperature sensors in ceramic powders face challenges in achieving mechanical resilience, electrical insulation, and preventing contamination, especially at high temperatures, while also dealing with the limitations of short pot life and difficulty in precise dosing of ceramic castings, leading to inefficiencies and waste.
Innovation Solution
A method involving a cup-shaped casting mold where a first and second component are introduced alternately or simultaneously, with the mold being vibrated to mix and compress the ceramic casting compound, allowing for precise filling and elimination of air bubbles, thereby creating a solid ceramic block encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic powder is mixed with water or liquid in large quantities and allowed to set slowly, then the ceramic casting can harden and encapsulate the sensor element, but the casting can only be poured and dispensed for a relatively short time after mixing, leading to waste and inefficiency
Solution Approach 1:
The patent applies mechanical vibration during the mixing and pouring process to accelerate the setting reaction of the ceramic casting compound. By vibrating the mold during filling and initial setting, the patent extends the usable pot life and ensures complete encapsulation without premature hardening
Solution Approach 2:
The patent prepares the ceramic casting compound by pre-mixing the ceramic powder with binding agents and additives before use. This preliminary preparation optimizes the flow and setting characteristics, allowing the compound to remain dispensable for a longer period while maintaining encapsulation quality
2Ease of manufacture
If conventional mixing and pouring methods are used for ceramic castings, then the process is simple, but the casting can hardly be pumped and dosed in a defined manner, leading to imprecise filling and waste
Solution Approach 1:
The patent uses mechanical vibration during the dosing and filling process to maintain the ceramic casting compound in a pumpable and dispensable state. The vibration prevents premature setting and ensures precise, controlled filling of the mold cavity with the required amount of material
Solution Approach 2:
The patent employs pumping and dosing equipment to deliver the ceramic casting compound from a storage container to the mold in controlled amounts. The system uses fluid dynamics principles to pump the viscous ceramic slurry through hoses and dispensing nozzles with precision
3Strength
If ceramic powder is used to encapsulate sensor elements, then the sensor elements can be fixed, but the connecting wires may not be sufficiently electrically insulated from each other and from the housing at high temperatures
Solution Approach 1:
The patent uses a composite ceramic casting compound consisting of ceramic powder (such as alumina or magnesia) combined with binding agents and electrical insulation additives. This composite material provides both mechanical fixation strength and electrical insulation properties, even at high temperatures up to 600°C and above
Solution Approach 2:
The ceramic casting compound creates an inert, non-conductive environment around the connecting wires and sensor elements. The ceramic material's inherent electrical insulation properties prevent unwanted electrical conduction between wires and from wires to the metal housing, ensuring reliable electrical isolation
4Strength
If ceramic powder is compressed to fix sensor elements, then the sensor elements can be secured, but contamination and chemical changes in the sensor element cannot be fully ruled out over longer periods
Solution Approach 1:
The ceramic casting compound forms a hermetic, chemically inert encapsulation around the sensor element. This encapsulation protects the sensor from contamination by process media, moisture, and oxygen, preventing chemical changes and degradation over long periods while maintaining mechanical fixation
Solution Approach 2:
The ceramic casting compound acts as a protective shell or encapsulation layer surrounding the sensor element. This shell provides both mechanical support and chemical protection, isolating the sensitive sensor from the external environment while allowing the sensor to function
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 method enables reproducible mixing and precise dispensing of ceramic castings, even with short pot life, resulting in a stable and insulated sensor encapsulation suitable for high-temperature applications, reducing waste and improving mechanical resilience and electrical insulation.
Implementation Method 1
the mold is vibrated and / or made to oscillate at a predetermined frequency
Implementation Method 2
air bubbles, which usually remain in the casting with conventional mechanical stirring and lead to undesirable porosity after curing, are stimulated by the vibration to rise and outgas
Implementation Method 3
the casting compound with at least the following steps: that at least a predeterminable quantity of the first component of the casting compound is introduced into the casting mold, that at least one predetermined amount of the second component of the casting compound is introduced into the mold
Data Source
Figure 1
AI summary
The invention relates to a method for producing a measuring device for determining and/or monitoring at least one process variable, wherein at least one sensor element is introduced into an at least partially crucible-shaped mold, and wherein a casting compound, consisting of at least one first component and a second component, is used to at least partially fill the mold. According to the invention, the casting compound is used to fill the mold at least partially utilizing at least the following steps: at least one predeterminable amount of the first component of the casting compound is introduced into the mold, at least one predeterminable amount of the second component of the casting compound is introduced into the mold, and the mold is shaken and/or vibrated at a predeterminable frequency. The invention further relates to a method for casting an at least partially crucible-shaped mold.