Morphological Adaptation for Speed Control of Pipeline Inspection Gauges MC-PIG

Passive and active hybrid pipeline inspection gauges (PIGs) have been used for in-pipe inspection. While a passive PIG cannot control its speed, the hybrid version can achieve this by using an integrated valve specifically designed and embedded in the PIG. This study proposes a generic new method for speed adaptation in PIGs (called MC-PIG) by introducing a generic, modular, controllable, external valve unit add-on for attaching to existing conventional (passive) PIGs with minimal change. The MC-PIG method is based on the principle of morphological computation with closed-loop control. It is achieved by regulating/computing the PIG's morphology (i.e., a modular rotary valve unit add-on) to control bypass flow. Adjustment of the valve angle can affect the flow rate passing through the PIG, resulting in speed regulation ability. We use numerical simulation with computational fluid dynamics (CFD) to investigate and analyze the speed of a simulated PIG with the valve unit adjusted by proportional-integral (PI) control under various in-pipe pressure conditions. Our simulation experiments are performed under different operating conditions in three pipe sizes (16″, 18″, and 22″ in diameter) to manifest the speed adaptation of the PIG with the modular valve unit add-on and PI control. Our results show that the PIG can effectively perform real-time adaptation (i.e., adjusting its valve angle) to maintain the desired speed. The valve design can be adjusted from 5 degrees (closed valve, resulting in high moving speed) to a maximum of 45 degrees (fully open valve, resulting in low moving speed). The speed of the PIG can be regulated from 0.59 m/s to 3.88 m/s in a 16″ pipe at 4.38 m/s (in-pipe fluid velocity), 2500 kPa (operating pressure), and 62 °C (operating temperature). Finally, the MC-PIG method is validated using a 3D-printed prototype in a 6″ pipe. Through the investigation, we observed that two factors influence speed adaptation; the pressure drop coefficient and friction of the PIG and pipeline. In conclusion, the results from the simulation and prototype show close characteristics with an acceptable error.

A first dedicated heart valve unit: safe and streamlined patient care for the rapidly growing field of transcatheter heart valve interventions

Background A dedicated Heart Valve Unit was launched in 2018 to meet the demands of the growing transcatheter heart valve program by optimizing patient care in a single dedicated unit. Purpose To assess the performance of the heart valve unit (all steps of patient care in a single unit with intermediate care facilities) over a conventional approach (preparation on a normal ward, postprocedural intensive care unit (ICU) monitoring and transfer to an additional monitoring ward before discharge) in a high volume center. Methods Retrospective analysis including patients undergoing transcatheter mitral or tricuspid valve repair who were admitted to the Heart Valve Unit (02/2018–01/2020) compared to a conventional patient care approach (02/2016–01/2018). Patients who were already preprocedurally admitted to the ICU or in whom ICU monitoring postprocedurally was mandatory (direct annuloplasty, valve replacement) were excluded. The Heart Valve Unit patient care algorithm is presented in figure 1. We assessed procedural numbers, length of hospital stay, length and need for ICU monitoring, patient transfers between wards and periprocedural safety including in-hospital mortality. Results We observed a 164% increase in procedures (521 vs. 316 in total, 369 vs 282 with mitral valve procedures and 152 vs 34 tricuspid valve procedures) with the launch of the Heart Valve Unit over the 2-year-interval compared to the earlier time period. Length of in-hospital stay was significantly decreased compared to a conventional approach (9±7 vs. 12±11 days, p<0.001). In particular, postprocedural stay could be shortened from 7±7 to 5±6 days (p<0.001). Patients were less transferred between different wards in the Heart Valve Unit setting (p<0.001). Whereas all patients were postprocedurally transferred to the ICU in the conventional setting, only 16% of patients required an ICU bed immediately after the procedure due to complex interventions, intraprocedural events or high-risk comorbidities. The length of stay on ICU declined from 1.4±1.4 to 0.5±2.2 days. Among the patients re-transferred to the Heart Valve Unit directly after the procedure, 2% (10 patients) required an ICU bed in the further course due to hemodynamic instability (2), severe bleeding (4), seizures (1), ventricular fibrillation (1), anaesthetic overhang (1) or after urgent surgery due to a atrioventricular fistula (1). After stabilization, all patients were re-transferred to the Heart Valve Unit and discharged hereinafter. There was no intra-hospital death among these patients. Conclusions A dedicated Heart Valve Unit allows a safe and optimized patient care structure for transcatheter valvular interventions by combining all pre- and postprocedural steps in a single unit, thereby decreasing length of in-hospital stay to meet increasing economic demands. ICU capacity can be specifically used for complex procedures aftercare and complication monitoring. FUNDunding Acknowledgement Type of funding sources: None.

Trends in pneumatics – digitalization

The paper presents an overview of the latest technology trends in pneumatic automatization at Festo, focusing on digitalization from a component to a system level. The Festo Motion Terminal (VTEM) is valve terminal, designed for digitalization. Unique valve unit design allows valve functions to be defined by a software and to be changed in a running system very quickly, even on the fly. Model based applications on a valve controller offer many advanced functionalities such as: pneumatic servo positioning, force and torque control of pneumatic drives and pressure or flow regulation in pneumatic systems. VTEM native connectivity with higher order controllers adds a possibility to seamlessly integrate it on all levels, from the field to the cloud. User control logic and/or AI algorithms in a combination with digitalized pneumatics allows new services, such as: auto-commissioning, predictive maintenance, increased energy efficiency, automatic leakage detection within pneumatic systems and many others.

Consideration of the Insulation Design Method on a ± 200 kV Converter Valve Unit in an HVDC Converter Hall

A converter valve unit, which converts Alternating Current (AC) to Directing Current (DC) and DC to AC, is one of the key elements of high voltage direct current (HVDC) transmission. The insulation design of a converter valve unit should be considered for air clearance according to the DC superimposed overvoltage and the insulator that maintains the insulation performance and the corona shield to suppress DC corona discharge. There is no prescribed standard for the insulation design of a converter valve unit. Moreover, insulation performance under an applied DC voltage has not yet been thoroughly investigated. Therefore, it is necessary to study the insulation design method of the converter valve unit. In this paper, consideration of the insulation design method on a ± 200 kV converter valve unit in an HVDC converter hall is performed. The finite element method (FEM) is used to simulate the 3D model. Additionally, the safety factor () is applied in accordance with the dielectric test in IEC 62271-1. As a result, an insulation design process on the converter valve unit is proposed and the insulation design is carried through the design factors. It is confirmed that design factors on the air clearance, insulator and corona shield have a significant effect on a highly reliable insulation design.

Experimental Assessment on Air Clearance of Multiple Valve Unit Considering Switching Impulse and DC Superimposed Switching Impulse

Multiple valve unit (MVU), which converts AC to DC and DC to AC, is one of the key elements of high voltage DC (HVDC) transmission. Therefore, the insulation design of MVU against overvoltage should be considered for the stable and reliable operation of HVDC transmission system. Especially, the air clearance of MVU should be calculated based the switching impulse, since it is fatal to MVU in terms of electrical insulation. However, the previous studies were limited to wave front, and the air clearance of the switching impulse is specified only for an ultra-high voltage (UHV) above 750 kV. As a result, it is difficult to calculate the air clearance of MVU which must endure for a switching impulse under 750 kV. In addition, when the switching impulse introduced while the MVU is in normal operation, it is superimposed to DC and creates the most severe situation, but the studies on such subjects are also insufficient. Therefore, as a fundamental step to calculate the air clearance of MVU, the dielectric characteristics of switching impulse and DC superimposed switching impulse in air have been investigated. The experiments on switching impulse showed that the critical flashover voltage was varied according to the curvature of electrode in the gap distance, up to eight times of the electrode radius. However, beyond that gap distance, the critical flashover voltage became similar, regardless of the radius of electrodes. In case of the superimposed experiment, it was performed according to DC pre-stress level and the polarities of switching impulse. The results were most severe when the positive switching impulse was superimposed on the positive DC, and the peak voltage at which flashover occurs was independent of DC pre-stress.

Use of Barkhausen noise for residual stress definition after diamond smoothing of high-pressure branch pipes

The results of residual stress definition after a valve unit diamond smoothing of high-pressure fittings are shown. In the paper there is used Barkhausen noise method allowing the definition of the residual stress level at a great depth as compared with the X-ray method. There is presented a procedure for the definition of residual stresses according to a ratio of a magnetoelastic parameter – deformation. The advantage of the diamond smoothing as a method of FSD allowing the decrease of tensile residual stresses and the increase compression stresses on a contact surface of fittings units is shown.

Diagnostics of the condition of sucker-rod pumping units after the analysis of dynamogram cards

Despite of the increased share of oil wells equipped with submersible electrical centrifugal pumps, a considerable part of them is equipped and operated with sucker-rod pumping units. When operating wells with sucker-rod pumping units, different plunger pumps are used. The rod string is operated in severe environment due to long contact with highly corrosive well products and time-variant loads. Taking into account all acting loads, the diagnostics of the condition of sucker-rod pumping units is a difficult task. At the majority of oil fields in Russia, the operation of wells equipped with sucker-rod pumping units is controlled by portable and stationary dynamographs of various models. Moreover, dynamographs are used, as a rule, only to obtain images of dependence of the force on the polished piston rod upon its stroke. Based on dynamograms it is possible to find the well flow rate, pump capacity, force on the polished piston rod, etc. But one of the main problems to be solved with the help of dynamometry is the forecasting of down-hole equipment condition in the process of further operation. In this paper we overview the methods to diagnose the condition of sucker-rod pumping units based on dynamograms. The aim of the work is to develop the mathematical model to forecast the failures of down-hole pumping equipment on the results of dynamometry to automatize the control process of the unit operation. The research tasks are to analyze the existing methods for diagnosing the condition of sucker-rod pumping units, and to develop the mathematical model for forecasting the failure of the valve unit leakage. As a result, the method for forecasting the increased failure on the example of the fluid leakage in the pump injection unit is proposed. The permissible boundaries of the change in the relative force on the polished piston rod are drawn up. As a result, the failure increase is forecasted based on the frequency of the relative force on the polished piston rod getting within the interval obtained.