Radial Labyrinth Seal for Rotary Piston Pump Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotary lobe pumps face issues with fluid leakage and wear due to short-circuit flow between the pressure and suction sides, especially when handling solids, leading to premature wear and failure of transmission components.
Innovation Solution
A sealing device with a labyrinth gap that extends further in the radial direction than the axial direction is implemented, utilizing centrifugal acceleration to increase flow resistance and enhance sealing, with a ratio of radial to axial sealing path components ranging from 1 to 15, and featuring a compact design with alternating radial and axial gap sections and co-rotating and stationary sealing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing labyrinths are used in rotary lobe pumps, then fluid leakage is reduced to some extent, but short-circuit flow occurs at the end faces of rotary lobes causing severe wear
Solution Approach 1:
The sealing labyrinth is designed with a predominantly radial orientation instead of conventional axial orientation. By extending the sealing path primarily in the radial direction (from outer diameter toward the shaft) rather than axially, the invention creates a sealing mechanism that effectively blocks the short-circuit flow path at the end faces of rotary lobes, thereby preventing wear while maintaining sealing effectiveness
Solution Approach 2:
The invention changes the geometric parameters of the sealing labyrinth by specifying that the radial sealing path length should be greater than the axial sealing path length. This parameter change optimizes the sealing effect by increasing flow resistance in the radial direction, preventing fluid from taking the short-circuit path through the end faces of rotary lobes
2Reliability
If sealing path is extended in axial direction, then sealing effect is improved, but device becomes less compact
Solution Approach 1:
Instead of extending the sealing path axially which would increase device length, the invention redirects the sealing path extension into the radial dimension. The sealing labyrinth extends from the outer diameter region radially inward toward the shaft, achieving effective sealing while maintaining a compact axial footprint and overall device compactness
3Reliability
If radial seal is provided between rotating and stationary parts, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
The sealing device is segmented into multiple sealing members arranged in series along the radial sealing path. These sealing members create multiple sealing stages within the labyrinth gap, enhancing sealing effectiveness through cumulative effect while keeping each individual sealing member relatively simple in structure
Solution Approach 2:
The sealing members act as intermediary elements between the rotating rotor and the stationary housing. These intermediaries create the labyrinth gap that provides the radial sealing path, effectively isolating fluid-free areas from the pump chamber while managing the complexity through standardized sealing component design
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 effectively reduces fluid leakage and wear on the piston and shaft seals, increasing the service life of the shaft seal and allowing for easy maintenance by isolating the fluid-free areas from the pump chamber, while maintaining a compact and space-efficient design.
Implementation Method 1
a centrifugal acceleration acts on the fluid, which causes an increase in the flow resistance of the fluid in relation to its radial movement component
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an apparatus for sealing off, in particular in the region of a shaft feedthrough, a pump space of a rotary piston pump with respect to a fluid-free region of the rotary piston pump, wherein the apparatus has two or more sealing members, which are arrangeable in such a way next to an end side of a rotary piston, arranged on the shaft, in the pump space of the rotary piston pump, that a labyrinth gap extends between the sealing members, said labyrinth gap being configured to extend the seal path in relation to the shaft in the radial direction and in the axial direction. According to the invention, the seal path in the radial direction in relation to the shaft is longer than the seal path in the axial direction in relation to the shaft.