Progressive Cavity Pump Sealing Assembly for Planetary Rotor Motion
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Solution Overview
Problem
Sealing the rotor of a progressive cavity pump, which undergoes planetary motion, is challenging due to its complex rotational movement, leading to fluid leakage and pressure oscillations.
Innovation Solution
A sealing assembly using an elastic conical diaphragm that grips the rotor and seals to the stator, comprising an outer retaining sleeve, an elastic diaphragm, and an inner retaining sleeve with an O-ring to maintain a seal and dampen pressure oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing method is used for a rotor rotating only about its own axis, then sealing is relatively simple, but the rotor of a progressive cavity pump undergoes planetary motion making sealing more difficult
Solution Approach 1:
The patent employs an elastic diaphragm as a flexible membrane to create the sealing surface. This diaphragm can deform to accommodate the planetary motion of the rotor while maintaining sealing contact with the stator, replacing rigid sealing structures that would fail under such complex motion conditions.
Solution Approach 2:
The sealing solution transitions from static sealing structures to dynamic sealing where the elastic diaphragm continuously adapts its shape and position to follow the rotor's planetary motion. The diaphragm's elasticity allows it to dynamically maintain sealing contact despite the varying relative positions between rotor and stator.
2Productivity
If the rotor undergoes planetary motion, then the pump can provide large or small rates of flow, but fluid leakage occurs due to difficulty in sealing
Solution Approach 1:
The elastic diaphragm forms a flexible sealing membrane that conforms to the rotor's planetary motion trajectory, preventing fluid leakage while allowing the full range of rotor movements necessary for variable flow rate operation.
Solution Approach 2:
The elastic diaphragm acts as an intermediary sealing element between the rotor and stator, transferring the sealing function from direct contact between rigid components to a flexible intermediate layer that can accommodate planetary motion without compromising seal integrity.
3Reliability
If the rotor is sealed to the stator, then fluid leakage is prevented, but pressure oscillations occur due to the oscillatory nature of fluid flow
Solution Approach 1:
The elastic diaphragm's flexibility allows it to absorb and dampen pressure oscillations by deforming in response to pressure variations, while still maintaining continuous sealing contact to prevent fluid leakage.
Solution Approach 2:
The elastic nature of the diaphragm provides inherent cushioning against pressure oscillations, absorbing pressure shocks before they can propagate through the system, thus reducing pressure variations while maintaining seal integrity.
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
Effectively prevents fluid leakage and reduces pressure fluctuations in progressive cavity pumps by ensuring a secure seal and damping fluid flow oscillations.
Implementation Method 1
an elastic conical diaphragm that effectively forms a seal between the moving and rotating rotor of the pump and the stator of the pump... the elastic diaphragm acts to reduce variations in pressure due to the oscillatory nature of the fluid flow
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A sealing assembly for a progressive cavity pump and a progressive cavity pump assembly having a retaining sleeve, a ring, and an elastic diaphragm terminating in a first end of the diaphragm in a first opening, and in a second end of the diaphragm, opposite the first end, in a second opening larger than the first opening. The second opening is held in contact with the retaining sleeve by the ring, and the first opening is configured to grip a rotor of the progressive cavity pump, and the ring is configured to hold the second opening fixed with respect to a stator of the progressive cavity pump.