Slip Ring Seal Supply Line Placement for Dry Running
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Solution Overview
Problem
Mechanical seals in water pumps face challenges with short service life due to the use of soft/hard sliding pairs, which are prone to thermal damage and dry running issues, despite the use of special carbon-graphite materials for low sealing gap temperatures, and require a cooling/lubricating medium to maintain performance.
Innovation Solution
The mechanical seal design incorporates a supply line between the radial housing base and sleeve, allowing for easy adjustment and placement of a cooling/lubricating medium in the collection space, ensuring it remains for extended periods, even during dry running, by utilizing an annular gap and strategically positioned ventilation openings to promote medium retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft/hard sliding pair is used for the mechanical seal, then the sealing gap temperature is reduced and dry running properties are improved, but the service life is shortened due to lower resistance to abrasive attack
Solution Approach 1:
The mechanical seal is provided with a collection space that is pre-filled with a cooling/lubricating medium before operation. This preliminary action ensures that the soft/hard sliding pair has immediate lubrication protection when starting, enabling dry running capability while extending service life by preventing abrasive wear during operation.
2Duration of action of stationary object
If a hard/hard sliding pair is used for the mechanical seal, then the service life is extended, but the dry running properties and cooling requirements are worsened
Solution Approach 1:
The collection space is pre-filled with cooling/lubricating medium before operation, providing immediate thermal management and lubrication. This allows hard/hard sliding pairs to operate with reduced heat generation and wear, extending service life while maintaining reliable cooling during operation.
3Duration of action of stationary object
If the supply line is provided with adjustable height between the radial housing base and sleeve, then the cooling/lubricating medium retention time is extended, but the device complexity increases
Solution Approach 1:
The supply line height is adjusted as a variable parameter between 0.5 and 4 mm to optimize medium retention time. By treating the height as an adjustable parameter rather than a fixed dimension, the system achieves extended medium retention while maintaining relatively simple construction through straightforward dimensional modification.
4Ease of manufacture
If the supply line runs radially in a straight line, then the ease of manufacture is improved, but the medium flow control and retention capability are reduced
Solution Approach 1:
The supply line is configured to run radially between the housing base and sleeve, utilizing the radial dimension to create an extended flow path. This radial arrangement naturally increases medium retention time by lengthening the flow path without adding axial or circumferential complexity, maintaining ease of manufacture while improving medium retention capability.
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 extends the service life of mechanical seals by maintaining a sufficient cooling/lubricating medium in the collection space, preventing premature wear and ensuring effective lubrication and cooling of sliding partners, even when the pump is not filled with medium.
Implementation Method 1
The heat generated in the sealing gap between the mating ring and the sliding ring must neither lead to thermal damage to the sliding partners themselves nor to thermal damage to the sealing components surrounding the sliding partners.
Implementation Method 2
The mechanical seal is provided with a collection space containing a cooling/lubricating medium that gives the mechanical seal the required resistance to dry running
Data Source
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AI summary
The mechanical seal comprises a counter ring (10) and a sliding ring (12) housed in a casing (24, 36) containing a collection chamber (41) for a cooling/lubricating medium, into which at least one supply line (39) opens. To facilitate easy attachment of the supply line (39) to the mechanical seal, it is located between a radial base (38) of the casing (24, 36) and a radial annular section (8) of a sleeve (5) to which the counter ring (10) is rotationally fixed. Since the supply line (39) is limited by components of the mechanical seal, it can be easily attached to the mechanical seal according to specific requirements; in particular, the height of the supply line (39) can be easily adjusted. Furthermore, the arrangement of the supply line (39) allows the cooling/lubricating medium in the collection chamber (41) to remain there for a longer period when the mechanical seal operates dry.