Pressure Sensor Sleeve Isolates Lateral Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure sensors used in injection molding face issues with erroneous measurements due to lateral and radial pressure from low-viscosity media, which cause deflection of the membrane and incorrect signal generation, especially when the mounting conditions are unfavorable.
Innovation Solution
A sensor design featuring a pressure sleeve coaxially arranged with the housing axis, tightly connected to the sensor on the front side, with a gap extending further axially from the pressure chamber than the force path via the measuring element, allowing the pressure sleeve to withstand lateral pressure without transferring it to the inside, and incorporating a thick-walled pressure sleeve to minimize deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thin membrane is used to improve response time and resolution, then measurement precision is improved, but the membrane becomes more susceptible to deflection from lateral pressure causing measurement errors
Solution Approach 1:
The pressure sleeve acts as an intermediary component between the low-viscosity media and the sensor housing. It absorbs the lateral pressure from the media and transfers it to the tooling plate through its outer surface, preventing direct transmission of this pressure to the sensor housing and membrane assembly. This mediator structure allows the membrane to remain thin for fast response while being protected from pressure-induced deflection errors.
2Strength
If the housing wall is made thicker to resist lateral pressure, then structural strength is improved, but the attachment of the membrane to the housing deteriorates
Solution Approach 1:
The pressure resistance function is segmented from the housing structure and assigned to a separate pressure sleeve component. This allows the housing to maintain thin walls for optimal membrane attachment while the pressure sleeve provides the necessary structural strength to withstand lateral pressure. The segmentation of functions between these two components resolves the contradiction between housing strength and membrane attachment quality.
3Ease of operation
If the sensor is mounted with a small gap distance in the tool, then ease of installation is improved, but low-viscosity media flows into the gap causing radial pressure and measurement errors
Solution Approach 1:
The pressure sleeve converts the harmful radial pressure from media infiltration into a beneficial protective mechanism. By allowing the media to flow into the gap and exert pressure on the outer surface of the pressure sleeve, the design transforms the harmful infiltration into a controlled pressure application on the sleeve's outer surface. This pressure is then distributed to the tooling plate, preventing it from reaching the sensor housing and causing measurement errors. The mounting gap remains small for ease of installation while the harmful media infiltration is converted into a protective pressure distribution mechanism.
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 design significantly reduces erroneous measurements by isolating the radial pressure from the force path, maintaining the accuracy of the measuring element and improving the sensor's resistance to temperature changes and mechanical stress, while also enhancing the attachment of the membrane to the housing.
Implementation Method 1
a measuring element 13, for example a piezoelectric crystal
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A sensor for measuring pressures in low-viscosity media for use in injection molding includes a housing with an axis A, a flat end face to be exposed to a pressure space, and a diaphragm that is arranged on the end face and is permanently connected to the housing. A measuring element that can infer a pressure prevailing in the pressure space on the basis of deflection of the diaphragm is arranged behind the diaphragm. A pressure sleeve that is tightly connected to the sensor on the end face and is arranged at a distance from the housing with a gap behind this connection is arranged coaxially with the housing axis A outside the housing. The gap extends axially further across the measuring element than the region of the force path in the direction away from the pressure space.