Filter Holder With Removable Drive And Spring Tensioning
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Solution Overview
Problem
Existing filter holders with hydraulic drives cannot be autoclaved with filter cassettes clamped in place due to undesirable pressure increases from hydraulic fluid expansion, and they lack precision in adjusting clamping pressure during filtration and sterilization processes.
Innovation Solution
A filter holder design featuring movable plates on rails with a removable drive and tension rods having spring tensioning elements, allowing for precise clamping pressure adjustment and enabling autoclaving of filter cassettes with the clamping mechanism removed, ensuring the filter holder can be sterilized in an autoclave and reused.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hydraulic drive is used to clamp filter cassettes with predefinable pressure, then clamping pressure precision is improved, but the filter holder cannot be autoclaved due to hydraulic fluid expansion causing high pressures
Solution Approach 1:
The patent removes the hydraulic drive from the autoclavable filter holder design. Instead, it uses a mechanical drive with a spring element that can withstand autoclaving conditions. The hydraulic drive is extracted because it cannot tolerate the high temperatures and pressure changes of autoclaving, which would cause fluid expansion and damage the filter cassettes.
Solution Approach 2:
The patent changes the drive mechanism from hydraulic to mechanical with a spring element. The spring element is designed to maintain a maximum clamping force of 200 N during autoclaving, which is sufficient to keep filter cassettes sealed but low enough to prevent damage. This parameter change allows the system to survive autoclaving while maintaining functional clamping pressure.
2Object-affected harmful factors
If a mechanical drive with spring tensioning element is used for autoclaving, then autoclavability is improved, but clamping pressure adjustment precision deteriorates
Solution Approach 1:
The patent employs a dynamic clamping system where the spring element can be pre-compressed to different degrees before autoclaving. The compression amount is calculated based on expected thermal expansion, allowing the spring to maintain consistent clamping force (around 200 N maximum) throughout the autoclaving process. This dynamic adjustment compensates for temperature-induced dimensional changes.
Solution Approach 2:
The spring element is pre-compressed before autoclaving to account for thermal expansion that will occur during the process. This pre-compression acts as a cushion that absorbs the expansion forces, preventing excessive clamping pressure while maintaining sufficient pressure to keep filter cassettes sealed. The spring's elastic properties provide built-in compensation for thermal effects.
3Object-affected harmful factors
If the drive is made removable to enable autoclaving, then sterilization capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the filter holder into distinct segments: an autoclavable frame with rails and a non-autoclavable drive unit. The drive can be removed from the frame before autoclaving and reinstalled afterward. This segmentation allows the autoclavable components to be sterilized while protecting the sensitive drive mechanism from damage, simplifying the overall sterilization process despite the additional removal/reinstallation step.
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 allows for precise clamping pressure during filtration, prevents pressure increases during autoclaving, and enables the filter holder to be sterilized and reused, ensuring the integrity of filter cassettes and the filtration process.
Implementation Method 1
at least one tension rod having a spring tensioning element is provided parallel to the at least one rail by means of which the two plates can be connected to each other and can be clamped against the filter cassettes with a predefinable tension rod pressure
Implementation Method 2
Because of the hydraulic fluid of the hydraulic drive, undesirable expansion would take place in the hydraulic cylinder, which would result in high clamping pressures or forces
Data Source
AI summary
A filter holder for receiving filter cassettes (19) and a method for sterilizing the filter are provided. The filter holder has first and second parallel plates (3, 4). The first plate (3) is fixed and the second plate (4) is movable along at least one rail (2) by a drive (7, 9) so that the filter cassettes (19) can be clamped between the plates (3, 4) with a predefined clamping pressure. The drive (7, 9) is designed to be removable. The at least one rail (2) has at least one tension rod (5) with a spring clamping element (6) so that the first and second plates (3, 4) can be clamped with a pre-definable pressure against the filter cassettes (19).