Stationary Spring Double Seal for Centrifugal Pump Shaft Deflection
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Solution Overview
Problem
Conventional shaft seals in centrifugal pump units face issues with high shaft deflections, reduced service life, complex assembly, and increased production costs due to dynamic spring elements causing vibrations and exposing sliding surfaces during maintenance.
Innovation Solution
A double seal module with two stationary mechanical seals in a tandem arrangement, where spring elements are integrated into non-rotating components, and the space between the seals is flushed with a liquid from the pump's housing parts, eliminating the need for external fluid supply and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If dynamic spring elements are used in conventional mechanical seals, then contact force between sliding ring and counter ring is generated, but vibrations occur and service life is reduced
Solution Approach 1:
The patent inverts the conventional design by making the spring element stationary rather than dynamic. The sliding ring is now the moving component that rotates with the shaft, while the spring element remains fixed in the stationary part of the mechanical seal. This inversion eliminates vibrations caused by rotating spring elements while maintaining the necessary contact force between the sliding ring and counter ring.
2Reliability
If conventional mechanical seals are used, then sealing function is provided, but complex assembly and maintenance are required
Solution Approach 1:
The patent segments the mechanical seal into distinct functional components: a stationary part containing the spring element and counter ring, and a rotating part containing the sliding ring. This segmentation allows for simplified assembly where the rotating part can be independently installed on the pump shaft, and the stationary part is mounted in the pump housing. Maintenance is also simplified as the sliding ring can be accessed and replaced without disassembling the entire seal assembly.
3Ease of repair
If sliding surfaces are exposed for maintenance, then repair work can be performed, but maintenance risks increase
Solution Approach 1:
The patent introduces a protective covering or housing that encloses the sliding surfaces during operation but can be opened or removed during maintenance. This intermediary structure allows the sliding surfaces to be protected from contamination and damage during normal operation, while providing safe and controlled access during maintenance activities. The design enables maintenance personnel to work on the sliding surfaces without direct exposure to harmful factors such as rotating shafts or pressurized fluids.
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 enhances the seal's tolerance to shaft deflections, ensures reliable operation, and reduces maintenance risks by providing a compact, cost-effective, and easily installable solution with integrated lubrication, thus extending the service life and improving assembly efficiency.
Implementation Method 1
each pairing is assigned a spring element to generate a contact force between the sliding ring and counter ring
Implementation Method 2
a space between the sliding ring-counter ring pairings is flushed with a liquid from the reservoir
Data Source
Figure 1
AI summary
The invention relates to a shaft sealing arrangement for a centrifugal pump. The arrangement is provided with a module (4). The module (4) comprises a first slide and mating ring pairing (5) and a second slide and mating ring pairing (6). The pairings (5, 6) are positioned in a tandem arrangement to one another. A spring element (11, 12) is assigned to each pairing (5, 6) . The spring elements (11, 12) generate a pressure force between the slide ring (9, 10) and the mating ring (7, 8). A space between the slide ring-mating ring pairings (5, 6) is rinsed with a liquid from a store (22). The spring elements (11, 12) are arranged in stationary structural components.