Centrifugal Pump Casing Seal Structure for Gap Stability
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Solution Overview
Problem
Centrifugal pump sealing gaps between housing parts are prone to opening or enlargement due to pressure and temperature-induced deformations, leading to sealing failures, especially in high-pressure and high-temperature applications like ebullator pumps, where radial sealing arrangements face challenges in maintaining effective sealing.
Innovation Solution
The introduction of an annular protrusion on the first housing part that engages with an annular recess on the second housing part, preventing the opening of the sealing gap and ensuring even loading of the radial sealing element, thus maintaining a reliable seal under pressure and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radial sealing arrangements are used for sealing between housing parts, then the sealing element can be arranged coaxially with the pump shaft, but the sealing gap opens or enlarges due to pressure and temperature-induced deformations of the housing parts
Solution Approach 1:
The patent changes the geometric parameters of the housing parts by providing an annular protrusion on the first housing part that engages with an annular recess on the second housing part. This geometric modification compensates for pressure and temperature-induced deformations, maintaining the sealing gap stability and preventing opening of the sealing gap under high pressure differentials.
Solution Approach 2:
The annular protrusion and recess arrangement is designed in advance to counteract the harmful effect of housing part deformations. The engagement between the protrusion and recess pre-establishes a mechanical constraint that prevents the sealing gap from opening due to radial expansion or bending of the housing parts under pressure.
2Strength
If the first housing part is fixed with respect to the second housing part, then the radial expansion of the first housing part results in opening of the sealing gap, but the securing elements provide firm connection between housing parts
Solution Approach 1:
The patent segments the sealing function from the structural connection function. The annular protrusion and recess provide a dedicated sealing mechanism that is separate from the securing elements (bolts and nuts) that provide structural connection. This segmentation allows the sealing arrangement to compensate for deformations independently while maintaining firm mechanical connection.
Solution Approach 2:
The annular protrusion acts as an intermediary element between the first housing part and the second housing part. It mediates the interaction between the two housing parts by providing a controlled engagement interface that maintains sealing gap stability while allowing the securing elements to provide firm structural connection.
3Ease of operation
If the sealing element is arranged in a curved surface, then radial sealing is achieved, but the sealing gap opens at the high pressure side due to housing part expansion
Solution Approach 1:
The patent introduces an additional dimensional constraint by providing the annular protrusion that extends in the axial direction and engages with the annular recess. This axial dimension constraint prevents radial expansion of the sealing gap, complementing the radial sealing arrangement and maintaining sealing reliability under high pressure differentials.
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 configuration effectively reduces the opening of the sealing gap and ensures a consistent, reliable sealing function even under extreme conditions, preventing deformation-induced failures and maintaining proper sealing performance.
Implementation Method 1
The first axial end surface is provided with an annular protrusion that engages with an annular recess provided in the second axial end surface
Implementation Method 2
the sealing element for sealing between the adjacent housing parts... the outlet pressure of the fluid that may be 1000 bar or even more is also acting upon the connection between the barrel and the end cover
Data Source
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AI summary
A pump casing for a centrifugal pump is proposed, the pump casing extending in an axial direction (A) and having a first housing part (2), a second housing part (3) for being sealingly attached to the first housing part (2), a plurality of securing elements (4) for linking the first and the second housing part (2, 3), and a radial sealing element (5) for sealing between the first and the second housing part (2, 3), wherein the first housing part (2) has a first axial end surface (21), and the second housing part (3) has a second axial end surface (31), said first and second axial end surfaces (21, 31) facing each other, and wherein the first axial end surface (21) comprises an annular protrusion (22) extending in the axial direction (A) and the second axial end surface (31) comprises an annular recess (32) configured for engaging with the annular protrusion (22), wherein the annular protrusion (22) is arranged radially inwardly with respect to the securing elements (4). In addition, a centrifugal pump is proposed.