Contamination Indicator with Thermal Actuation for Hydraulic Filters
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Solution Overview
Problem
Contamination indicators in hydraulic systems inaccurately signal contamination levels during cold start-ups due to temperature-induced changes in fluid viscosity, leading to false readings.
Innovation Solution
A temperature-dependently active actuation device is integrated upstream of the indicating device, which activates only when the fluid reaches a predefinable threshold temperature, ensuring accurate contamination detection by using a differential pressure indicator or back pressure indicator, with a valve device featuring a movable closing body or spool that opens upon thermal expansion, providing improved thermal coupling and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contamination indicator uses a movable element acted upon by pressure on the dirty side, then it can indicate the degree of contamination, but it generates false readings during cold start-up due to temperature-induced viscosity changes
Solution Approach 1:
The patent introduces a temperature-dependent actuation device that activates the indicating device only after a predetermined temperature has been reached. This preliminary temperature check ensures that contamination measurements are only taken when the fluid viscosity is within the acceptable range, preventing false readings during cold start-up conditions.
Solution Approach 2:
The patent employs a temperature-dependent actuation device as an intermediary between the pressure source and the indicating device. This actuation device mediates the signal transmission by only allowing the contamination indication to pass through when temperature conditions are appropriate, thereby filtering out false readings caused by cold viscosity effects.
2Productivity
If the indicating device is activated during cold phases, then it provides continuous monitoring, but it produces display errors due to insufficient fluid temperature
Solution Approach 1:
The system performs a preliminary temperature assessment through the temperature-dependent actuation device before activating the contamination indication. This ensures that continuous monitoring is only effective when temperature conditions support accurate measurements, preventing display errors during cold phases.
Solution Approach 2:
The patent makes the activation of the indicating device dynamic by linking it to temperature conditions. The indicating device is not continuously active but rather dynamically activated only when the fluid reaches the predetermined temperature, adapting its operation to environmental conditions to maintain measurement accuracy.
3Measurement precision
If the flow resistance is used as a contamination indicator, then it reflects the contamination level, but it is influenced by fluid viscosity changes with temperature
Solution Approach 1:
The temperature-dependent actuation device serves as an intermediary that filters out temperature-induced viscosity effects before they reach the contamination indication system. By controlling when the indication is active based on temperature, it prevents viscosity changes from corrupting the contamination measurement.
Solution Approach 2:
The patent changes the operational parameters of the indicating device based on temperature conditions. By adjusting the activation state of the indicating device according to temperature thresholds, it compensates for the harmful effect of viscosity changes on flow resistance measurements.
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 solution minimizes display errors caused by temperature changes, ensuring accurate contamination monitoring and preventing false indications during cold-start conditions, thereby enhancing measurement precision and reliability.
Implementation Method 1
The closing body can be moved into the open position through the thermal expansion of the expansion element
Implementation Method 2
The expansion element comes into contact with fluid and is coupled with the closing body in such a way that this closing body can be moved into the open position through the thermal expansion of the expansion element
Data Source
AI summary
A contamination indicator is for filter elements (12) for fluids that are replaceably housed in a filter housing (2). The indicator has a fluid-conveying connection (58) to the interior of the housing (2) and possesses an indicating device (52) providing information concerning the degree to which the filter element is contaminated (12). A temperature-dependently active actuation device (50) is connected upstream from the indicating device (52) in the direction of fluid inlet. By the actuation device, the indicating device (52) is activated when the fluid temperature has reached a predefinable threshold value.