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This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start.

For the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease.

When point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%.

The introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.

The rotor in screw motor is driven to rotate by highly pressure difference of drilling fluid (DF), while rotor drives drill bit to break rocks. DF works in the volume cavity (VC) which exists between the stator and rotor (SAR), these process realizes the conversion from hydraulic energy to mechanical energy finally. In order to assure seal performance and output power reliability of VC in common hypocycloid screw motor (CHSM), it’s essential to survey SAR end-face profile.

In this article, based on the internal and external cycloid method given for SAR end-face of φ172 7/8-head LZ type CHSM, the interference among SAR is established based on the meshing model through theoretical equilibrium method (TEM). Last, the reasonable design value of SAR interference in TEM is verified with the hydraulic parameters test results.

The profile optimization that top-root part of rotor end-face profiles is replaced by elliptical-circular arcs (ECA) makes the transition area of tooth-top and tooth-root connect smoother than before. The reasonable interference of SAR in TEM is almost 0.16mm~0.22mm to ensure better sealing performance. Through the hydraulic test, the interference positive fluctuation or the number of SAR head reduces increase (starting-pressure-drop) SPD while negative fluctuations by contraries. Meanwhile, DF penetration also decreases the revolution speed with the SAR interference decreases. The less SAR head revolution speed is always below the more with the constant driving power and DF hydraulic drop. Ultimately, decreasing in overall-efficiency occurs for larger fluctuation of interference or or less interference among SAR.

The line type optimization and analysis in TEM for CHSM improves the motor seal and output performance, also has important application values simultaneously.

This paper aims to clarify the relationship between the cone bit seal failure and the down-hole drilling fluid pressure and high temperature that occur during ultra-deep well drilling. It proposes that the contact pressure distribution under low pressure conditions is favourable for lubrication and the seal inner wear is serious under high pressure conditions. Furthermore, the more reliable cone bit seal can be obtained using the back propagation (BP) neural network and genetic algorithm (GA) to reduce the drilling cost.

The wear morphologies of the seal surface were analyzed using Contour GT-K to determine the seal contact pressure distribution. Then, the influences of the drilling fluid pressure and high temperature on the metal seal interface were analyzed using finite element method. The structural parameters of the seal under high pressure were optimized based on the BP neural network and GA.

This paper proposes that the inner seal contact pressure increases rapidly with an increase in the drilling fluid pressure. The design parameters of the seal components should be adjusted reasonably to ensure that the outer contact pressure is greater than the inner contact pressure, which is advantageous for forming a lubricant film on the inner side of the seal. The uneven temperature distribution of the seal surface will further aggravate seal failure.

Study on the bit seal with good property is significant in drilling application, and the optimized seal can prolong the cone bit life.

The NEW GOODYEAR PUMP now being produced by Goodyear Pumps Ltd., Cambourne, Cornwall, a subsidiary of Holman Bros. Ltd. claims a truly amazing performance. Invented by the Cornishman, James W. Goodyear, who has had over 20 years' experience of hydraulics, it makes use of a ‘continuous’ piston. The pump is a continuous, self‐priming, self‐lubricating one, of positive axial‐flow employing a screw rotor of entirely new form. The screw engages with a rotating plate to produce a pulseless action that is virtually positive. In fact, rotor and plate are the only moving parts and since the rotor spins on its true centres there is no tendency to roll around and rub against the surrounding rubber stator which can often be troublesome with this type of conventional pump, The rotor shaft is supported on roller bearings which are protected by lip seals. The rotor can turn in either direction so that direction of flow can be chosen at will. Mechanical face seals running on ground and lapped surfaces seal the shaft, and a chamber between seals and bearings is vented to atmosphere to prevent build‐up of fluid pressure.

Finishing Today's Bicycles The name Raleigh is undoubtedly one of the best known in cycling throughout the world and Kemira Coatings are proud to be their leading supplier of liquid surface coatings.

Brief Particulars of Recently Introduced Materials likely to have Aircraft, Missile or Space Vehicle Applications. Two new nickel‐based casting alloys—EPK 36 and EPD 16—which have been developed in the Rcsearch Laboratories of the International Nickel Company (Mond) Ltd. are now under experimental production at the Hereford Works of Henry Wiggin and Co. Ltd. Specially developed to meet demands for improved high‐temperature service and intended for the manufacture of precision investment‐cast rotor and stator blades in aircraft gas turbines, both the new alloys are vacuum‐melted and vacuum‐cast.

Power‐electronic systems have been playing a significant role in the integration of large‐scale wind turbines into power systems due to the fact that during the past three decades power‐electronic technology has experienced a dramatic evolution. This second part of the paper aims to focus on a comprehensive survey of power converters and their associated control systems for high‐power wind energy generation applications.

Advanced control strategies, i.e. field‐oriented vector control and direct power control, are initially reviewed for wind‐turbine driven doubly fed induction generator (DFIG) systems. Various topologies of power converters, comprising back‐to‐back (BTB) connected two‐ and multi‐level voltage source converters (VSCs), BTB current source converters (CSCs) and matrix converters, are identified for high‐power wind‐turbine driven PMSG systems, with their respective features and challenges outlined. Finally, several control issues, viz., basic control targets, active damping control and sensorless control schemes, are elaborated for the machine‐ and grid‐side converters of PMSG wind generation systems.

For high‐power PMSG‐based wind turbines ranging from 3 MW to 5 MW, parallel‐connected 2‐level LV BTB VSCs are the most cost‐effective converter topology with mature commercial products, particularly for dual 3‐phase stator‐winding PMSG generation systems. For higher‐capacity wind‐turbine driven PMSGs rated from 5 MW to 10 MW, medium voltage multi‐level converters, such as 5‐level regenerative CHB, 3‐ and 4‐level FC BTB VSC, and 3‐level BTB VSC, are preferred. Among them, 3‐level BTB NPC topology is the favorite with well‐proven technology and industrial applications, which can also be extensively applicable with open‐end winding and dual stator‐winding PMSGs so as to create even higher voltage/power wind generation systems. Sensorless control algorithms based on fundamental voltages/currents are suggested to be employed in the basic VC/DPC schemes for enhancing the robustness in the entire PMSG‐based wind power generation system, due to that the problems related with electromagnetic interferences in the position signals and the failures in the mechanical encoders can be avoided.

This second part of the paper for the first time systematically reviews the latest state of arts with regard to power converters and their associated advanced control strategies for high‐power wind energy generation applications. It summarizes a variety of converter topologies with pros and cons highlighted for different power ratings of wind turbines.

The concept of high shear mixing/milling using a high speed rotor/stator principle has been used successfully in most sectors of the process industries, including food, dairying, pharmaceuticals, fibres, plastics, paper etc.

The Italian company Axis has extended its expertise. It has built a robotic line for a domestic appliance manufacturer, as Brian Rooks reports.

Unishear Mixers were exhibiting a range of high shear mixers with the emphasis on the UNS and UNL Rotashear mixer range. Both systems cover a wide range of products in the paint, ink, chemical, food and pharmaceutical industries etc., using low and high abrasive materials.