Rotary Head Research Articles

Simulation Analysis of Sealing Performance of Rubber Core of Rotary Blowout Preventer

The performance of rotary control head or rotary blowout preventer will directly affect the success or failure of the underbalanced construction of oil and gas well. Once the failure occurs in the construction process, there may be blowout and other big drilling accidents. Based on the Yeoh constitutive equation, the dynamic sealing model of rubber core is established in this paper, and the sealing process of rubber core during tripping and tripping is calculated and analyzed. Then, the effect of the bubble defect in the core on the sealing performance of the core under different drilling fluid pressure was analyzed. Finally, the effect of metal degumming on the sealing performance of the core was analyzed. The results showed that the larger the initial sealing pressure and contact stress value of the Mises core was, the better the sealing effect of the Mises core was, while the larger the Mises stress value was, the more likely the Mises core was to suffer fatigue failure. The drilling fluid pressure significantly affects the maximum equivalent stress of the core, and the maximum equivalent stress appears in the bubble position inside the core at different times and under different drilling fluid pressure. The degumming position is placed in the contact position between metal and rubber core. When the tensile stress exceeds the limit of rubber core material, radial and circumferential cracks will occur on the upper surface of rubber core. With the increase of drilling times, rubber is prone to fatigue cracks, which eventually lead to mutual tearing.

METHODS OF ENERGY SAVING IN DEVICES FOR HYDRO-CRACKING OF SCALE

The cause of scale formation on the cast blanks and in the process of ivy is considered, the difference between the physical properties of the scale and base metal is shown, which reduces the quality and stability of the metal, and also complicates the processing of the product. The proposed effective way to remove the scale, which is environmentally friendly, does not require additional water treatment and does not deform the metal surface. The analysis of devices for removal of scale from the metal surface showed that the first collectors with nozzles had problems with operation: high water and energy consumption and poor cleaning of the metal surface. They are proposed to replace them with a hydraulic device with a rotary principle with rotary heads that use very low cost at high impact pressure, which also reduces electricity consumption. A comparative table of ordinary collectors and collectors with a different principle is provided by improving the design of devices for supplying fluid to the metal surface with the quality of cleaning of the metal from scale. Electricity is proposed. It is revealed that you can reduce the eager expenses by optimizing the operation of the pumping station. The optimization result is given in the form of an energy saving schedule in the period of hydraulic pauses by means of an adjustable electric drive with frequency control and hydraulic rods. It is proposed on the basis of the analysis of devices for removal of scale another way to reduce electro -energy by improving the design of water supply devices to the metal surface by improving their properties. It is revealed that not only the features of the design of the nozzles, but their optimal location, plays an important role in removing the scale. The hydraulic scale system is fully controlled by the machine, which allows to regulate the parameters of removal of the scale and to provide the required working pressure in the system, to compensate for the wear of the nozzles.

Stress corrosion cracking of 316LN stainless steel with orthogonal scratches

316LN stainless steel is used to produce the third generation primary circuit pipe of pressurized water reactor (PWR). Its internal and external pipe surfaces are generally introduced with scratches when manufactured, transported and installed processes, making their research and discovery on the stress corrosion cracking (SCC) sensitivity challenging. In the present study, multiple orthogonal scratches on 316LN stainless steel are prepared using the rotary cutting head. The effects of the orthogonal scratches on the SCC of 316LN stainless steel are investigated. The experimental results show that the force bearing point of this kind of rotary cutter head is near 60° on the side, which is different from the common cutter head. At the intersection of orthogonal scratches, larger strain concentration and more oxide particles can be formed comparing with single scratch. With increasing strain concentration, the more nucleation sites and the greater growth driving force for the oxide particles can be formed. Thus larger and more oxide particles in this case are generated, resulting in finally a greater SCC sensitivity.

A Low-Cost System for Far-Field Non-Anechoic Measurements of Antenna Performance Figures

Prototype measurements are the key step in the development of antenna structures. Typically, their far-field characteristics are validated in expensive, dedicated facilities such as open range sites, or anechoic chambers. Despite being necessary for obtaining high-precision data (e.g., for device qualification), the use of costly infrastructure might not be fully justified when the main goal of measurements includes demonstration of the methodology behind determination of the performance figures of interest (e.g., for the purpose of teaching), or rough validation of the EM simulation model correctness. From this perspective, systems for far-field measurements in non-anechoic environments represent an interesting alternative to the utilization of the state-of-the-art equipment and facilities. Despite their proven usefulness, the mentioned systems are normally constructed around the expensive, laboratory-grade equipment, which contradicts the whole concept of low-cost measurements. This paper discusses a cost-efficient, mobile system for experimental validation of antennas. Its main components include the in-house developed rotary heads, an open-hardware-based vector network analyzer, and the measurements post-processing software. The cost of the system amounts to only around 3630 USD. The capabilities of the device have been demonstrated through measurements of two antenna structures. The considered performance figures include radiation pattern and single-direction gain vs. frequency. Comparisons against the measurements performed in benchmark conditions (anechoic chamber), as well as using professional network analyzer have also been provided. Furthermore, the documentation that facilitates the construction of the system components is shared in an online repository.

Comparing the performance of several tool coatings in turning of commercially pure titanium grade 4

The increasing use of titanium and its alloys in the manufacture of implants results from the simultaneous presence of excellent biocompatibility, relatively low density, high mechanical properties, and corrosion resistance. Unlike the excellent application characteristics, titanium is classified as a difficult-to-machine material. Therefore, one constant challenge for implant manufacturers is to correctly choose turning tools for each application. This work aims to compare the useful life of the uncoated insert with other three types of coatings on carbide tools, titanium aluminum nitride (TiAlN), aluminum chromium nitride (AlCrN), and titanium nitride/titanium carbonitride multilayer coating (TiN + TiCN). Turning experiments were performed using grade 4 commercially pure titanium (typically used in dental implants), testing two cutting speeds for each tool used. The tests were carried out in a CNC rotary head lathe, using cutting fluid in abundance. The results showed that the uncoated insert achieved the shortest life due to its worst properties (lower surface hardness, higher friction coefficient, and lower maximum working temperature), even with its supposedly higher chemical stability with titanium. On the other hand, the tool with the TiN + TiCN multilayer coating obtained the longest tool life among the four tested inserts. The main novelty of this work is that the tool that showed the longest life (TiN + TiCN coating) did not have the best properties among the tested coatings. In fact, it had both the lowest hardness and working temperature. However, this tool has a low coefficient of friction and a multilayer structure coating, which increases its resistance against the wear mechanism that occurred predominantly in this application, which was attrition. Even with the increased cutting speed, this coating also achieved the best result. Therefore, during the machining of titanium, the most important characteristics of the tool are low coefficient of friction and resistance against the pull out of particles.

Effects of a rotary shear field on the interlayer bond and mechanical properties of polylactide fabricated using fused filament fabrication

Polylactide (PLA) is a kind of distinct semicrystalline polymer and widely applied for fused filament fabrication (FFF), because of its low price and high mechanical properties. But the bad interface of FFF printed PLA parts and their high mechanical anisotropy limit their industrial application deeply. In this work, an innovative FFF 3D printer with a rotary shear head was developed to control the interface and crystallization of FFF printed PLA parts. Compared with traditional FFF, the tensile strength of specimen fabricated via the rotary shear field increases from 21.1 MPa to 59.3 MPa, and the degree of mechanical anisotropy decreases from 0.41 to 0.09. As indicated by the meso-structure morphologies, not only the triangular voids between adjacent strands were disappeared, but also the randomly-distributed shish-kebab structure crystals and fibrils were obtained by the rotary shear field treatment. And the DSC results showed a high crystallinity value of 26.1% of specimen with the rotary shear field treatment. Therefore, the good interface, randomly-distributed crystals and high crystallinity contribute the effort to increase the tensile strength and decrease the degree of mechanical anisotropy of FFF printed PLA parts.

Effects of a rotary shear field on the interlayer bond and mechanical properties of carbon-fiber-reinforced plastic composites fabricated using fused deposition modeling

One of the key issues restricting the wider application of parts fabricated by fused deposition modeling (FDM) in various fields is the lack of interlayer bonding, owing to layer-by-layer deposition. This issue results in poor mechanical properties and strong mechanical anisotropy of FDM-printed parts. Moreover, this is more critical for FDM-printed parts made of fiber-reinforced composite materials. In this study, an innovative FDM 3D printer with a rotary print head was developed to enhance the tensile strength of parts fabricated from short carbon fiber (CF)-reinforced polylactic acid (PLA) composites. The rotary speed of the print head was a dominant parameter affecting the tensile properties of the parts. The optimal rotary speed was at 200 rpm at a raster angle of 0°, which offered a 1.5-fold enhancement in the tensile strength and 6-fold reduction in anisotropy. In addition, a rotary speed of 200 rpm caused greater entanglement of the polymer chains, whereas increasing the speed to 300 and 400 rpm led to less entanglement. Notably, the rotary shear field provides “in situ” regulation of microstructure formation during the 3D printing process. The results of this study can be useful in enhancing the mechanical strength and reliability of industrially manufactured FDM parts.

Skeleton Curve-Guided Five-Axis Sweep Scanning for Surface With Multiple Holes

Although surface with multiple holes (SMHs) is widely used in industrial components, the precise inspection of SMH is a knotty task due to the inefficiency of traditional surface inspection technology. Recently, a five-axis surface sweep scanning approach is emerging and shows great potential to boost the surface inspection efficiency by sensing surface in a continuous sweep scanning way. However, an efficient sweep scanning path should cater to the unique kinematic characteristics of the five-axis inspection system. In this article, we present an approach to automatically generate efficient five-axis sweep scanning paths for inspecting SMH. First, the skeleton of SMH is extracted along with the surface partitioned into several patches, based on which a guiding curve-based sweep scanning path can be defined for each surface patch. By modeling the skeleton of SMH as a directed Euler graph and finding a proper sequence to traverse the graph, a continuous five-axis sweep scanning path is then generated to sweep all patches without any transition among them. The nonsweeping time could be eliminated so that the sweep scanning efficiency is drastically improved in this way. Simulation and physical inspection experiments are conducted on two SMHs, showing that our method significantly outperforms existing approaches, such as the popular zigzag method and the method from the leading commercial software of RENISHAW. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This article aims to generate an efficient sweep scanning path of a five-axis coordinate measuring machine (CMM) for inspecting the SMHs of a precision component, such as an engine block or a gearbox cover. Although traditional five-axis CMM path generation methods can be applied to SMH inspection, most of them are designed for the point-by-point inspection mode, which intrinsically suffers from extremely low efficiency. Recently, an emerging five-axis surface sweep scanning technology shows great potential for boosting the efficiency of surface inspection by using a continuous surface sensing stylus mounted on a rapid rotary probe head. The realization of high-speed five-axis surface scanning depends on a proper sweep scanning path which takes advantage of the superior kinematic performance of the rotary probe head as much as possible and accordingly avoids assigning heavy workload to the three linear axes with weaker kinematic performance. However, up to date, only a handful of five-axis sweep scanning path planning methods are reported and mainly focus on the simple and compact surface. Therefore, existing methods are incompetent to generate a suitable sweep scanning path for high-speed inspection of SMH. For these reasons, we present a novel and practical approach to automatically generate a continuous five-axis sweep scanning path for complex SMH. The generated path exactly meets the unique kinematic requirements of high-speed five-axis inspection and eliminates all noninspection operations. In this way, the SMH inspection can be accomplished with high efficiency.

Performability of electro-hydro-mechanical rotary head of drill rig in open pit mining: A case-study

The test subject is the electro-hydro-mechanical rotary-and-feed mechanism of roller-bit drill rigs with undermount rotary head. The goal of the research is the capacity stimulation, vibration reduction and reliability improvement of drill rig model SBSH-250MNA-32. The article describes the studies in the field of mining machines and the relevant engineering solutions. It is critical for Russia to preserve and replenish its mineral resources and mineral reserves to pursue social and economic advance. The priority growth of coal and gold production using the advanced open pit mining method can increase percentage of the latter in cumulative mineral mining by not less than 50%. Furthermore, it is necessary to cut down costs of production by 4&ndash;5%. The main and extremely labor consuming process in open pits in Russia is drilling which takes up to 40% of total mining cost [1&ndash;3]. The common method of drilling in rocks with the hardness factor of 6&ndash;20 on Protodyakonov&rsquo;s scale in Russia is the roller-bit drilling [4&ndash;6]. This drilling processes is accompanied with high dynamic loading imposed on the rotary-and-feed mechanism [7&ndash;9]. One of the ways of reducing dynamic loads in the roller-bit drill rigs is redesigning of the rotary-and-feed mechanism to possess higher safety and anti-vibration properties, simpler structure, as well as better performability and longevity [7, 8, 10&ndash;13]. This article describes and substantiates the design and operating principle of the electro-hydro-mechanical rotary head, its prototype testing, the research program and procedure, the instrumentation preparation, the research objective as well as the test data processing and analysis as a case-study of drill rig model SBSH-250MNA-32.

Design and experimental study on a novel sealing structure of rotary control head for coalbed methane underbalanced drilling

In order to reduce the failure accidents of dynamic seal ring and rubber core of conventional rotary control head, a novel rotary control head for coalbed methane underbalanced drilling is developed in this paper. According to the material selection requirements of the rubber core and dynamic seal assembly, the mechanical properties experiments of hydrogenated nitrile rubber materials with three different formulations were carried out. According to the design scheme of the rotary control head, the toothed slip ring combined seal is selected, and the finite element analysis and experimental research are carried out on the seal. Finally, through the field test, the working performance of the novel special rotary control head for coalbed methane is tested. The experimental results show that there is no leakage in the static and dynamic sealing system during the application period. It shows that the designed sealing system is reliable.

Real-time model inversion control for speed recovery of hydrostatic drive used in the rotary head of a blasthole drilling machine

Real-time model inversion control for speed recovery of hydrostatic drive used in the rotary head of a blasthole drilling machine

Fatigue optimization of rotary control head rubber core based on steady sealing

In the process of underbalanced pressure drilling, the drill pipe body and its joint repeatedly pass though the sealing rubber core of the rotating blowout preventer (RBOP), making the rubber core susceptible to alternating cyclic load, and prone to fatigue failure. Under the premise of effective sealing realized by the rubber core, to increase its service life, first the Yeoh constitutive model and constitutive parameters describing the material of rubber core were determined by uniaxial tensile and compression tests, and the finite element governing equation of the nonlinear large deformation of the rubber core was obtained according to the principle of virtual work; then a three-dimensional finite element model of the rubber core was established by ABAQUS software to simulate the dynamic sealing process, contact pressure and Mises stress distribution and variation on the sealing surface were analyzed, and the accuracy of the finite element analysis results was verified by comparing the existing test results; subsequently, the influence of structural parameters such as inner angle, outer angle and inner diameter on the sealing surface stress was studied, and these parameters were optimized through Taguchi experiment. The optimal combination of structural parameters was obtained as inner angle 29°, outer angle 69° and inner diameter 84 mm. The maximum Mises stress was reduced by 2.48 MPa and the Mises stress amplitude by 42% after optimization. Finally, the suitable conditions of the optimized rubber core were selected based on the applicability analysis to conduct the field application and result shows that the rubber core has good sealing performance and significantly increased fatigue life after optimization.

Establishment of a Rotary Print Head to Effect Residual Stresses and Interlayer Bonding in an FLM-Process

In fused layer modeling (FLM) manufacturing technology, there is an increased demand for semi-crystalline materials due to their favorable mechanical properties, such as high strength and toughness. The reasons for their limited use are process-related residual stresses and reduced interlayer bonding, resulting in component distortion, warping and poor strength. Addressing these problems, this paper presents the development and implementation of a rotary print head that enables local laser pre-deposition heating and forced air cooling in the 2.5-dimensional FLM process. Samples of polypropylene are fabricated to investigate the effects of the modified process on residual stresses and interlayer bonding. The investigations show that local laser pre-deposition heating can positively influence the interlayer bonding. In combination with a reduction of the extrusion temperature and additional cooling, it is possible to considerably reduce the residual stresses. The results of this research show that pre-deposition heating and forced air cooling significantly improve the processability of semi-crystalline thermoplastics in the FLM process.

An image-based algorithm for generating smooth and interference-free five-axis sweep scanning path

Five-axis continuous scanning inspection is an emerging technology in measuring free-form surfaces. Compared to the traditional three-axis scanning inspection, the five-axis continuous surface scanning tremendously boosts the inspection efficiency and suffers from less dynamic error due to adopting a special sweep scanning working mode, which lets the super-light and high-speed rotary two-axis probe head take over the majority of the inspection work. However, there has not been any efficient method to generate sweep scanning path for a free-form surface with external obstacle. The major problem is how to guarantee the non-interference condition during the scanning process. In this paper, a two-step algorithm for generating smooth and interference-free sweep scanning path is proposed. First, an image-based algorithm is proposed to incrementally calculate the admissible area of the stylus along the scanning path. Then an optimized B-spline fitting algorithm is proposed to find the optimal probe head trajectory within the admissible area, which simultaneously guarantees the smoothness and non-interference of the trajectory. In the real experiment, the average tangential velocity and acceleration of the machine's translational axes with the proposed five-axis sweep scanning path are only 16.45% and 17.19% of those with three-axis zigzag scanning path respectively. When inspecting a high-accuracy cylindrical surface with high scanning velocity, the root mean square of the surface profile error is 0.002 mm and 0.004 mm in five-axis scanning and three-axis scanning respectively. The experimental result manifests that the sweep scanning path tremendously helps to reduce the kinematic loads and the dynamic errors of the inspection machine.

The Dynamic Characteristic Analysis of an A/B Biaxial Rotary Milling Head

The biaxial rotary CNC universal milling head is an important functional part of the five-axis CNC machine tool, and its dynamic performance directly affects the machining accuracy of the machine tool. In this paper, the modal analysis and thermal error analysis of an A/B biaxial rotary milling head were carried out. The first six natural frequencies and modal shapes were obtained by the finite element method, and the modal test was carried out by LMS Test.Lab. The transient temperature field of the milling head during machining was obtained by the finite element method, and the thermal deformation experiment was carried out. The experimental results verify the validity of the finite element model within an acceptable error range. This paper provides theoretical references for the structural optimization and thermal error compensation of the A/B biaxial rotary milling head.

Temperature-dependent abrasivity of Bukit Timah granite and implications for drill bit wear in thermo-mechanical drilling

Thermo-mechanical drilling combines the advantages of flame thermal treatment and rotary head drilling to achieve a high penetration rate in granitic rocks and a low wear rate of drill bits. This drilling strategy has been recognized as a potential technique to develop deep geothermal energy, but further improvement is still needed to optimize the drilling efficiency, such as the reduction in drill bit wear in thermally treated rocks. We use the Cerchar abrasivity test to investigate the abrasivity characteristics of Bukit Timah granite after the thermal treatment at different high temperatures. The Cerchar abrasivity index (CAI) decreases from 3.5 at 25 °C to 3.0 at 400 °C, remains constant between 400 and 600 °C and subsequently increases to 4.1 at 800 °C. Based on the meso-scale and micro-scale observations using polarizing microscope, 3D scanner and scanning electron microscope, the reduction in CAI value at lower temperatures is due to the abrasive wear of stylus tip, while the mechanical interaction between the stylus cone and abrasive minerals causes the increase in CAI value at higher temperatures. The Cerchar abrasivity test results indicate that overheating rocks may result in the exposure of drill bits to more abrasive minerals and enhance drill bit wear.

Structural Design of Tool Head of Pipe Dredging Device

In the cold season, pipelines are prone to icing-induced clogging, causing great inconvenience to people’s production and life. To solve the icing-induced clogging of the pipeline, analysis was made on the reason why the original device fails to break the ice, to provide some guidance for conducting an innovative design of the cutter head of the device. Based on the actual needs for the cutter heads in the course of ice-breaking, a parallel inclined spherical rotary cutter head was proposed, and its 3D model created with the help of a modelling software. Through the operational and arc-traversing performance analyses of the cutter head, the relationship between the radial direction and the axial direction of the cutter head was constructed. The pressure relationship of the device was analysed. The conclusion was drawn as follows: the designed cutter head can improve the effectiveness of the device on ice-breaking and reduce the requirement for the structural intensity, providing a significant basis for the development of its physical prototype.

Changes in Vertebral Artery Blood Flow in Different Head Positions and Post–Cervical Manipulative Therapy

ObjectiveThe objective of this study was to investigate the hemodynamics of blood flow through the V3 region of the vertebral artery contralateral to the side manipulated during different rotary head positions and post–cervical spinal manipulation. MethodsThis quasi-experimental study was performed on 25 healthy, asymptomatic participants, both male and female, between 20 and 30 years of age. Each participant presented with a C0/C1 or C1/C2 cervical facet restriction (as determined by motion palpation). Participation was voluntary, and participants had no symptoms of vertebrobasilar artery insufficiency or contraindications to cervical spinal manipulation. Doppler ultrasound was used to measure vertebral artery blood flow (V3 region) hemodynamics, contralateral side of manipulation, as close to C1/C2 region as possible in 4 positions of cervical rotation (neutral, 45°, maximum, and post-manipulation neutral). Doppler ultrasound parameters included peak systolic flow velocity, end diastolic flow velocity, mean flow velocity, vessel diameter, and flow rate. The nonparametric Friedman test was used for analysis across each head and neck position, and post manipulation. ResultsNo clinical or statistically significant results (P > .05) were found for any of the hemodynamic parameters in any of the head positions. ConclusionsHemodynamic measurements of the V3 region of the vertebral artery do not show significant changes in the measured head positions or following manipulation of the upper cervical spine in patients without pre-existing risk factors.

Implicit Surface Modelling and Parametric Optimization for Self-cleaning Portable Toilets Using a Rotary Jet Head Cleaning in Grasshopper

Implicit Surface Modelling and Parametric Optimization for Self-cleaning Portable Toilets Using a Rotary Jet Head Cleaning in Grasshopper

Modeling and Simulation Approaches for Reliability Analysis of Drilling Machines

Drilling, as the initial stage of exploitation in open-pit mining, has a significant effect on subsequent mining stages. Any failure in a drilling machine stops the drilling operation and, as a result, all following operational phases come to a halt. The drilling system is the most important part of the drilling operation. This study selected two new rotary-type drilling machines (A and B) in Sarcheshmeh Copper Mine in Iran as a case study to perform a reliability and availability analysis of their drilling systems. The drilling system was divided into three independent subsystems; drill string, rotary head, and mast. The reliability modeling used a reliability block diagram and Monte Carlo simulation. Reliability and availability were evaluated, and the importance of each subsystem estimated. A preventive maintenance schedule was proposed using weighed reliability allocation to achieve the reliability target. The results show the mast is the most reliable subsystem. Importance measure analysis indicates the drill string and rotary head are the most critical subsystems of machines A and B, respectively. Finally, under the proposed maintenance policy, the reliability of the drilling systems of machines A and B is improved.