Gear Pump Shaft Seal Flushing Chamber Design
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Solution Overview
Problem
Existing gear pumps face issues with material deposits forming on shaft seals due to pumped media, leading to premature wear and increased leakage, especially when handling fluids that solidify or harden, such as adhesives.
Innovation Solution
A gear pump design featuring a concentric flushing chamber around the shaft sealing ring, connected to the pressure zone via a feed channel and the suction zone via a return channel, ensuring a continuous flushing flow that prevents fluid stagnation and material deposits, with optional throttles to manage differential pressures and minimize flushing flow volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recirculation system is used to enable regular exchange of leakage flows through the bearing point, then the leakage flow can be redirected, but the differential pressure at the bearing point increases leading to increased leakage flow and potential material deposits on the shaft seal
Solution Approach 1:
The harmful leakage flow that passes through the bearing point is extracted and diverted away from the shaft seal area. The return channel guides this leakage flow directly from the bearing point to the suction side, preventing it from contacting the shaft seal and forming material deposits, thus protecting the seal while managing the increased leakage flow.
Solution Approach 2:
The return channel acts as an intermediary pathway that mediates between the bearing point and the suction side. It provides a dedicated route for the leakage flow to return to the suction side without passing through or contacting the shaft seal, thereby eliminating the harmful effect of material deposits while maintaining the recirculation function.
2Ease of operation
If return threads are formed on the circumference of the pump shaft to support the return system, then the leakage flow can be conducted directly into the return conveying section, but the manufacturing complexity increases
Solution Approach 1:
The return channel is merged with the pump housing structure rather than being integrated into the pump shaft. This combining of functions allows the return flow system to be implemented through the housing instead of requiring complex threading on the shaft, significantly reducing manufacturing complexity while maintaining the ability to generate and conduct the return flow effectively.
Solution Approach 2:
The pump housing is given a multi-functional role by incorporating the return channel directly into its structure. The housing not only contains the pump components but also serves as the conduit for the return flow, eliminating the need for separate return threads on the shaft and simplifying the overall manufacturing process.
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 continuous flushing flow effectively prevents material deposits and wear on the shaft seal, reducing leakage and extending the seal's lifespan, particularly suitable for fluids that solidify or react chemically, while maintaining low-pressure scavenging flows even at high operating pressures.
Implementation Method 1
The pressure difference created across the supply channel and the return channel ensures an uninterrupted continuous flushing flow from the pressure zone to the suction zone of the pump
Data Source
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AI summary
A gear pump is described with a plurality of gear wheels which intermesh in order to deliver a pumping medium, are held rotatably in a pump case and deliver a pumping medium from a priming zone into a delivery pressure zone of the pump case. One of the gear wheels is driven by a pump shaft which protrudes with a coupling end out of the pump case. In order to seal the pump case, a shaft sealing ring is held around the circumference of the pump shaft, wherein, in order to avoid material deposits, the shaft sealing ring is assigned, according to the invention, an interior flushing chamber on the circumference of the pump shaft, the flushing chamber being connected to the delivery pressure zone of the pump case by a feed channel in the pump case.