Rotary Piston Pump Sealing Chamber for High-Pressure Shaft Protection
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Solution Overview
Problem
Rotary piston pumps face challenges in maintaining the service life of shaft mountings, drive means, and synchronization gear mechanisms due to fluid and particle invasion under high pressure conditions, leading to reduced reliability and lifespan.
Innovation Solution
A seal assembly with a sealing-fluid pump device that generates a fluid pressure differential using an eccentric element, a blocking chamber, and check valves to prevent fluid egress along the pump shaft, ensuring reliable sealing and maintaining pressure within the blocking chamber to counteract high resistance forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radial shaft seal rings and mechanical seal assemblies are used to prevent fluid invasion, then sealing is sufficient at low differential pressures, but fluid and particle invasion occurs at high differential pressures
Solution Approach 1:
The invention applies preliminary anti-action by creating a blocking chamber that is pre-filled with sealing fluid and maintained at a pressure higher than the pump chamber pressure. This pre-established pressure barrier actively prevents fluid and particle invasion before it can occur, rather than merely reacting to pressure differentials. The blocking chamber acts as a proactive defense mechanism that counteracts the harmful pressure gradient before it causes damage to mounting components.
Solution Approach 2:
The blocking chamber serves as an intermediary element between the pump chamber and the mounting components. It introduces a sealing fluid that acts as a mediator to prevent direct contact between the pumped fluid and the mounting components. This intermediary layer with controlled pressure differential provides an additional protective barrier that enhances sealing effectiveness beyond what conventional seals alone can achieve.
2Reliability
If conventional seal assemblies are used, then the structure remains simple, but service life is significantly reduced under high pressure conditions
Solution Approach 1:
The blocking chamber is nested within the existing pump housing structure, utilizing available space between the pump chamber and mounting components. The sealing fluid system is integrated into the existing hydraulic architecture, with the blocking chamber sharing the pump housing space. This nested arrangement adds protective functionality without requiring complete structural redesign, thereby limiting the increase in device complexity.
Solution Approach 2:
The blocking chamber serves multiple functions: it acts as a pressure barrier, a fluid seal, and a protective enclosure for the mounting components. The sealing fluid in the blocking chamber simultaneously prevents fluid invasion, maintains pressure differential, and lubricates the mounting components. This multi-functionality reduces the need for separate dedicated sealing systems, thereby limiting complexity increase while enhancing reliability.
3Reliability
If the blocking chamber is impinged with high fluid pressure to seal the pump chamber, then fluid egress is prevented, but energy consumption increases
Solution Approach 1:
The blocking chamber is impinged with a pressure that is partially excessive relative to the minimum sealing requirement. By maintaining a pressure differential that exceeds the maximum pump chamber pressure, the system ensures complete sealing effectiveness without requiring complex active pressure control systems. This partial excess action provides a safety margin that simplifies the overall system while achieving reliable sealing.
Solution Approach 2:
The sealing fluid in the blocking chamber is drawn from the pump's own hydraulic system, utilizing the pumped fluid itself as the sealing medium. The system self-regulates the pressure differential through the natural operation of the pump, without requiring external energy sources or active control mechanisms. The pump chamber pressure automatically charges the blocking chamber, creating a self-sustaining sealing system that minimizes additional energy consumption.
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 prevents fluid and particle ingress into sensitive components, enhancing the service life of rotary piston pumps by maintaining a controlled pressure differential and ensuring reliable sealing, even under high pressure conditions.
Implementation Method 1
a sealing-fluid pump device (220, 320a, 320b) having a pump inlet (221, 321a, 321b) and a pump outlet (222, 322a, 322b), by way of which a sealing fluid is conveyed into the blocking chamber (40, 140, 240, 340, 390) and by means of which the blocking chamber (40, 140, 240, 340, 390) is impinged with a fluid pressure
Implementation Method 2
a sealing-fluid pump device (220, 320a, 320b) having a pump inlet (221, 321a, 321b) and a pump outlet (222, 322a, 322b), by way of which a sealing fluid is conveyed into the blocking chamber (40, 140, 240, 340, 390)
Implementation Method 3
an eccentric element (423, 550) having an encircling eccentric circumferential face (450), by way of which the pump device (220, 320a, 320b) is driven
Data Source
AI summary
A seal assembly for sealing a pump shaft in a rotary piston pump configured for conveying pump-conveyed fluid comprises a sealing-fluid pump device having a pump inlet and a pump outlet. A blocking chamber is connected to the pump outlet and is disposed so as to neighbor the pump chamber of the rotary piston pump and is sealed in relation to the pump chamber by means of a first shaft seal that encloses the pump shaft. The blocking chamber by way of the pump outlet is impinged with a fluid pressure resulting from the fluid pressure differential that is generated by the sealing-fluid pump device, whereby said fluid pressure interacts with the first seal assembly to seal the pump chamber in relation to the egress of pump-conveyed fluid from the pump chamber along the pump shaft.