Hydraulic Tool Removable Coating for Swelling Compensation
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Solution Overview
Problem
Hydraulic drilling motors face issues with parts damage and misalignment due to swelling of elastomeric materials and thermal expansion, requiring a break-in period before reaching full operating pressure and flow rates.
Innovation Solution
A hydraulic tool with a stator and rotor featuring a removable coating that compensates for swelling and thermal expansion, allowing the tool to operate at design conditions without a break-in period by maintaining a constant clearance between the rotor and stator through controlled removal of the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resilient portion of the stator is designed to swell under drilling conditions, then the motor can form a seal at full operating pressure, but the swelling changes the spacing and fit of the rotor with the stator, causing misalignment and potential damage
Solution Approach 1:
The patent applies preliminary action by pre-installing the resilient portion in a compressed state within the stator housing before the motor is assembled and deployed. This preliminary compression accounts for the expected swelling that will occur when the motor reaches operating temperature and pressure conditions downhole. As the resilient portion swells during operation, it expands to the intended dimensions, maintaining proper spacing and fit with the rotor without causing misalignment or damage to metal components.
2Reliability
If the motor is made with rotors slightly undersized to allow room for swelling, then the resilient portion can swell without damage, but the motor must be operated at relatively lower pressures and power until the resilient portion swells enough to form a seal
Solution Approach 1:
The patent eliminates the break-in period requirement by pre-compressing the resilient portion during assembly. The rotor is manufactured at its final, full-size dimensions without being undersized. The resilient portion is installed in a compressed state within the stator housing, creating initial clearance that accommodates subsequent swelling. This allows the motor to immediately operate at full design pressure and power upon deployment, as the pre-compressed resilient portion gradually expands to form the seal without requiring a gradual pressure increase break-in period.
3Reliability
If the motor requires a break-in period at low pressure, then the resilient portion can swell gradually to form a seal, but this delays operation at full operating pressure and flow rates
Solution Approach 1:
The patent eliminates the break-in period by performing the swelling accommodation action in advance during assembly. The resilient portion is pre-compressed within the stator housing, creating built-in clearance that anticipates the thermal and pressure-induced swelling that will occur during operation. This preliminary configuration allows the motor to be deployed and immediately operated at full design pressure and flow rates, as the resilient portion gradually expands to its intended dimensions without requiring a gradual pressure increase period on the drilling rig.
Solution Approach 2:
The patent employs a disposable sacrificial coating applied to the rotor surface that is designed to be removed during the initial operation period. This coating provides temporary clearance accommodation while the resilient portion swells, and is then discarded as it wears away or is removed. This approach replaces the traditional time-consuming break-in period with a material-based solution that automatically provides the necessary clearance during the swelling process, allowing immediate operation at full pressure without delay.
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
Enables immediate operation at full pressures and flow rates without a break-in period, reducing wear on components and maintaining efficiency throughout the drilling process.
Implementation Method 1
The resilient portion typically swells under conditions encountered in drilling operations, such as due to chemical interaction with drilling fluids, thermal effects, or other factors.
Implementation Method 2
Metal parts of the motor may also expand with temperature, further changing the spacing and fit of the rotor with the stator.
Implementation Method 3
The coating may be removed during operation by abrasion, fracturing, tearing, peeling, blistering, thermal decomposition, chemical degradation, electrical degradation, or any other method or combination of methods.
Implementation Method 4
The coating may be removed during operation by abrasion, fracturing, tearing, peeling, blistering, thermal decomposition, chemical degradation, electrical degradation, or any other method or combination of methods.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
A hydraulic tool includes a stator, a rotor, and a removable coating. At least one of the stator and the rotor comprises a resilient material. The removable coating has a thickness compensate for expected swelling of the resilient material or an expected contraction of a clearance between the rotor and the stator based on thermal expansion. The removable coating is disposed on a surface of at least one of the rotor and the stator, and the removable coating is formulated to be removed during operation of the hydraulic tool. A method of operating a hydraulic tool includes passing a fluid through the hydraulic tool during rotation of the rotor within the stator and removing at least a portion of the removable coating responsive to rotation of the rotor within the stator as a volume of the resilient material increases responsive to contact with the fluid passing through the hydraulic fluid.