Rotary Pump Seal Housing Thermal Decoupling
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Solution Overview
Problem
Conventional centrifugal pumps with shaft sealing systems are limited by operating temperature and require external cooling fluids, which are costly and unreliable for high-temperature applications exceeding 160°C.
Innovation Solution
The seal housing is composed of an inner and outer part made of different materials, with a separate housing cover minimizing heat transfer and a remote return line for relief water, along with thermal decoupling and heat dissipation features such as ribs and air flow channels to manage heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the seal housing is made of a single material, then the manufacturing is simple, but it cannot simultaneously withstand high temperatures and provide effective heat dissipation
Solution Approach 1:
The seal housing is constructed as a composite structure with an inner housing made of heat-resistant material (such as stainless steel or heat-resistant alloy) to withstand high temperatures up to 300°C, and an outer housing made of heat-conductive material (such as aluminum or aluminum alloy) for effective heat dissipation. This composite material approach allows the single seal housing to simultaneously satisfy both high-temperature resistance and heat dissipation requirements.
2Reliability
If relief water is routed through the sealing chamber to cool the mechanical seal, then the seal cooling is effective, but the system is limited to operating temperatures below 160°C
Solution Approach 1:
The seal housing is segmented into an inner housing and an outer housing that are thermally decoupled. The inner housing contains the mechanical seal and is thermally isolated from the outer housing through thermal insulation structures (such as insulation layers or air gaps). This segmentation allows the inner housing to maintain high temperatures while the outer housing remains cool enough for relief water circulation, enabling seal cooling effectiveness at operating temperatures exceeding 160°C.
Solution Approach 2:
A thermal insulation layer or air gap acts as an intermediary between the inner housing and outer housing, blocking heat transfer from the high-temperature inner housing to the outer housing. This intermediary structure allows the system to operate at high temperatures while maintaining the outer housing temperature suitable for relief water cooling of the mechanical seal.
3Temperature
If external cooling circuits are used to cool the seal housing, then high-temperature operation is enabled, but the system becomes complex and requires external cooling fluids
Solution Approach 1:
The outer housing of the seal housing serves its dual function as both the structural enclosure and the cooling surface. Relief water from the pump system directly flows over the outer housing surface, utilizing the housing itself as the heat exchange surface without requiring separate external cooling circuits or additional cooling components. This self-service approach enables high-temperature operation while avoiding the complexity of external cooling systems.
4Reliability
If the return line for relief water is connected close to the seal housing, then the cooling is effective, but heat from the return line negatively impacts the shaft seal
Solution Approach 1:
The return line connection for relief water is extracted and positioned away from the seal housing and shaft seal area. The outer housing serves as the cooling surface where relief water flows, but the return line is routed to a location distant from the seal housing, preventing the hot return line from transferring heat back to the shaft seal. This extraction of the return line connection eliminates the harmful thermal feedback while preserving the cooling effectiveness.
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 enables reliable operation of centrifugal pumps at high temperatures without external cooling fluids, reducing heat conduction and maintaining seal integrity, thus enhancing the sealing system's efficiency and cost-effectiveness.
Implementation Method 1
the outer part is provided with a protective coating, plating or the like on its inside... The outer portion of the seal housing has better thermal conductivity than the inner portion. This allows the heat to be quickly dissipated to the outside.
Implementation Method 2
the seal housing has ribs with axial channels formed between them. The channels are preferably arranged in the outer part of the seal housing and are open towards the seal housing... Air preferably flows through the channels
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a centrifugal pump for delivering hot fluids, having a contacting shaft seal, a seal housing (13) for the shaft seal (14), and a return line (8) for a partial flow of the delivered fluid. No delivered fluid is discharged out of the seal housing, and a separate housing cover (9) is disposed between the seal housing (13) and the pump housing. A contact surface (25) minimizing the heat transfer between the seal housing (13) and the housing cover (9), and the return line (8) is connected to the housing cover (9) and/or to the pump housing (1).