Shaft Seal Pumping Ring Axial Flow Cooling
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Solution Overview
Problem
Conventional shaft seal apparatuses face challenges in effectively cooling rotary and stationary rings due to insufficient fluid discharge thrust, leading to inefficient fluid circulation and cooling performance, especially when discharge holes extend radially rather than axially, resulting in increased flow resistance and the need for additional pumping mechanisms.
Innovation Solution
A shaft seal apparatus featuring a pumping ring that generates axial fluid flow, a baffle member to orient the flow towards a discharge hole, and a design that includes inclined discharge holes and radial spaces to enhance discharge pressure and flow rate, eliminating the need for additional pumping in external piping and allowing for longer piping configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a partial impeller is used to pump fluid for self-circulation, then the shaft seal can be cooled, but the discharge thrust is insufficient and fluid circulation is inefficient
Solution Approach 1:
The pumping function is separated from the impeller and assigned to a dedicated pumping ring with radial vane structures. This segmentation allows the pumping ring to specialize in fluid circulation while the impeller focuses on power transmission, resolving the contradiction between cooling capability and circulation efficiency.
Solution Approach 2:
A pumping ring is introduced as an intermediary component between the impeller and the discharge hole. This pumping ring with radial vane structures acts as a mediator that enhances fluid circulation and discharge thrust, improving both cooling performance and circulation efficiency simultaneously.
2Device complexity
If a discharge hole extending in radial direction is formed, then the shaft seal structure is simplified, but discharge power becomes insufficient
Solution Approach 1:
The discharge hole is oriented in the radial direction rather than axially, utilizing the radial dimension for fluid discharge. Combined with the pumping ring's radial vane structures, this dimensional change maintains structural simplicity while enhancing discharge power through centrifugal force and radial flow patterns.
3Temperature
If external piping is lengthened to connect discharge hole and inflow hole, then cooling coverage is improved, but flow resistance increases and additional pumps are needed
Solution Approach 1:
The pumping ring is integrated into the shaft seal assembly itself, merging the pumping function with the sealing structure. This eliminates the need for separate external pumps and reduces flow resistance by shortening the fluid circulation path while maintaining adequate cooling coverage.
Solution Approach 2:
The shaft seal apparatus becomes self-sufficient by incorporating the pumping ring that autonomously circulates cooling fluid within the sealed space. This self-service mechanism eliminates dependency on external pumping systems, reducing energy loss from flow resistance in external piping.
4Ease of manufacture
If the shaft precision is reduced, then manufacturing cost decreases, but the geometrical tolerance for fluid flow orientation deteriorates
Solution Approach 1:
The pumping ring's vane structures are designed with optimized parameters including angle, length, and spacing that compensate for variations in shaft precision. This parameter optimization allows the system to maintain effective fluid circulation and discharge performance even with reduced manufacturing precision, lowering production costs.
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 improves discharge pressure and flow rate, enabling effective cooling of sliding rings with increased flexibility in apparatus arrangement and cooling performance, while maintaining geometrical tolerance and preventing fluid leakage even with reduced shaft precision.
Implementation Method 1
a centrifugal force, that is a force directed in a radially outward direction, is exerted on the fluid in the downstream side of the pumping ring by the circumferential flow generated resulting from the rotation of the rotational body
Implementation Method 2
a centrifugal force, that is a force directed in a radially outward direction, is exerted on the fluid in the downstream side of the pumping ring by the circumferential flow generated resulting from the rotation of the rotational body
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
A pumping ring (46), producing an axial flow of a sealed fluid so that a sealed fluid positioned in a sealed space (33) flows along the central axial direction of a rotating shaft (6), is secured to a rotating shaft (6) in an axial position different than a rotating ring (56). A discharge hole (14) is formed in the inner circumferential surface of a seal cover (8) positioned on the downstream side of the axial flow of the sealed fluid resulting from the rotation of the pumping ring (46). An inflow hole (15) is formed in a position on the upstream side of the axial flow of the sealed fluid resulting from the rotation of the pumping ring (46). The configuration is such that sealed fluid discharged from the discharge hole (14) returns to the interior of the sealed space (33) from the inflow hole (15). A rectifying member (18) is provided so as to protrude toward the inside in a radial direction in the inner circumferential surface of the seal cover (8) where the discharge hole (14) is formed. The rectifying member retains the flow of the sealed fluid along the rotational direction of a retainer (52) and orients the sealed fluid toward the discharge hole (14).