Progressing Cavity Gas Pump Lubrication and Cooling
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Solution Overview
Problem
Progressing cavity gas pumps used for delivering and compressing gas face issues with frictional heat generation due to dry running, leading to elastomer degradation and carbonization, as they lack lubrication and cooling, resulting in downtime and reduced efficiency.
Innovation Solution
A progressing cavity gas pump design featuring a stator with an elastomeric inner surface, a lubricant reservoir, and lubricant conduit devices, including a throttle nozzle, to provide lubrication and cooling, ensuring the rotor is lubricated before gas compression and allowing gravitational separation and recycling of lubricant, which cools and recirculates to maintain optimal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dry running is used in progressing cavity gas pumps, then the pump structure is simple and requires no lubrication system, but frictional heat generation causes elastomer degradation and carbonization
Solution Approach 1:
The patent introduces lubricant as an intermediary substance between the rotor and stator elastomer. The lubricant reservoir and conduit devices deliver lubricant to the pump chamber, where it forms a protective film on the elastomer surface, reducing direct friction and heat generation. This mediator prevents elastomer degradation while maintaining pump functionality.
Solution Approach 2:
The patent employs a hydraulic lubrication system where lubricant is pumped from the reservoir through conduits into the pump chamber. The lubricant flow is controlled and delivered precisely to the rotor-stator interface, using fluid dynamics principles to ensure proper lubrication without complex mechanical delivery mechanisms.
2Reliability
If lubrication is introduced to prevent frictional heat, then elastomer degradation is reduced, but the pump system becomes more complex with additional components
Solution Approach 1:
The lubrication system is merged with the pump structure by integrating the lubricant reservoir and conduit devices as inherent components of the pump housing. The lubricant delivery is combined with the existing pump chamber and rotor-stator assembly, creating a unified system rather than separate additive components.
Solution Approach 2:
The lubricant system is designed to be self-regulating and self-service. The reservoir automatically supplies lubricant through the conduit devices based on system operation, and the lubricant circulates and returns to the reservoir without requiring external control mechanisms. The system maintains itself through gravity and pressure differentials.
3Temperature
If lubricant is continuously supplied to the stator interior, then frictional heat is reduced, but lubricant management and separation from gas becomes complex
Solution Approach 1:
The distributor uses gravity as a counterforce to manage lubricant-gas separation. The downwardly extending lubricant branch-off and the downward slope toward the return line exploit gravitational pull to ensure lubricant naturally returns to the reservoir while gas continues to the outlet. This gravitational counterbalance simplifies separation without requiring additional mechanical separators.
Solution Approach 2:
The lubricant return line is positioned and sloped to create an equipotential flow path where lubricant naturally drains back to the reservoir under gravity. The distributor geometry ensures that lubricant and gas flow paths are optimized for their respective densities, with lubricant following the lower gravitational potential path back to the reservoir.
4Device complexity
If gravitational separation is used for lubricant return, then lubricant recycling is simplified, but the lubricant reservoir must be positioned below the stator
Solution Approach 1:
The lubricant return system utilizes the vertical dimension and gravitational field to achieve automatic lubricant separation and return. By positioning the reservoir below the stator and using the downward slope in the distributor, the system exploits the vertical dimension for gravity-driven lubricant flow, simplifying the recycling mechanism without requiring horizontal separation devices.
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 dry running, reduces frictional heat, and extends the lifespan of the elastomeric components, enhancing the pump's efficiency and reliability for gas delivery and compression by maintaining lubrication and cooling within the system.
Implementation Method 1
a lubricant reservoir (13) arranged upstream of the stator (2) and connected via lubricant conduit devices (14) with the stator interior (4)
Implementation Method 2
Integrate a throttle nozzle into the lubricant feed line
Implementation Method 3
a distributor (25) having a gas branch-off extending upward to the gas outlet (7) and having a lubricant branch-off extending downward to the lubricant return line (17) so that due to gravity, lubricant reaches the lubricant return line (17)
Implementation Method 4
the lubricant reservoir (13) is designed for cooling the lubricant contained therein and in particular the lubricant recycled from the stator interior (4)
Implementation Method 5
the pump rotor rotating within the stator generates frictional heat which results in a local overheating of the elastomer
Data Source
AI summary
A progressing cavity gas pump with a stator which has a stator interior with an elastomeric inner surface as well as a gas outlet and a gas inlet, between which a pump delivery direction is defined, and with a rotor which engages with the stator interior, wherein below the stator, a lubricant reservoir is arranged which is connected via lubricant conduit devices to the stator interior. A progressing cavity gas pumping method using a progressing cavity gas pump, gas coming from a gas inlet is delivered with a rotationally driven rotor within a stator and through a stator interior having an elastomeric inner surface to a gas outlet and is compressed, and wherein from a lubricant reservoir below the stator, a lubricant supply to the stator interior takes place via lubricant conduit devices, and lubricant from the stator interior is recycled via the lubricant conduit devices into the lubricant reservoir.