As a key component of Reciprocating pump, the valve has a significant influence on its performance. However, it is difficult for the existing valve to simultaneously solve the problems such as fatigue, erosion and cavitation in engineering application. In this paper, a solution to these problems of using variable stiffness spring is proposed. And three new structures of the valve are designed. Furthermore, based on Computational Fluid Dynamics (CFD) method, a three-dimensional dynamic simulation model considering fluid-structure interaction in the suction stroke of Reciprocating pump is established by using dynamic grid technique and User-Defined Functions (UDF). The performance of these new valves are compared with that of conventional valve respectively. The result shows that the new valves have significant influence on the motion characteristics of the valve disc, flow field distribution and cavitation. Besides, the simulation and experimental results of the maximum lift are compared, and it is found that they are basically in agreement. The new structures provide a new research direction for improving the performance of Reciprocating pump. Simultaneously, the above simulation method can also provide guidance for valve design, structural optimization and service life improvement.

Reciprocating diaphragm micro-pumps are the most common type among indirectly–driven micropumps. This paper addresses the hydroelastic vibration of a circular elastic diaphragm interacting with the incompressible and inviscid liquid inside the cylindrical chamber with a central discharge opening. Taking into account axisymmetric vibration of the diaphragm, the fluid pressure exerted upon the plate is formulated using linear Bernoulli’s equation. The kinematic and compatibility conditions are incorporated into the elastic vibration of the circular plate to derive the governing eigen-matrix equation. Numerical results are presented for different materials for diaphragm (silicon and glass) and pumped liquid (water and methanol). Normal frequencies of the coupled system, wet mode shapes of diaphragm and fluid oscillation modes are presented in numerical simulations. It is seen that the hydroelastic interaction lowers the natural frequencies considerably. However, the wet mode shapes for diaphragm vibration are very similar to the dry mode shapes. Finally, the effects of chamber height and operating fluid density on the normal frequencies are illustrated for the lowest four modes.

One of the old methods of butter production, which is still used in parts of Africa and the West of Asia, is the process of churning in the skin of a goat or deer that is half filled with milk or yogurt and air, which is beaten Reciprocating. This type of butter production in the current research is mechanized and is called machine-type Reciprocating butter churner (MRBC). This device is composed of chassis, churner, churn carrier, connector or crank, rotating wheel, driving system or power transmission and balance weights. In order to evaluate MRBC, the effect of churning amplitude (40, 60 and 80 cm), churning frequency (50, 61 and 72 cpm) and the churner volume (13.5 and 21.3 liters) on the butter yield was investigated. The results showed that the amplitude, frequency and churner volume had a significant effect on the butter yield at the level of 1%. Regardless of the churner volume, the minimum and maximum butter yield was obtained in the lowest and highest amplitude and frequency, respectively. The present study gives a general overview of the butter yield affected by machine mechanical parameters.

Introduction: The aim of the present study was to compare the amount of apical debris extrusion after preparation using hand files, Reciprocating files, and full rotary nickel-titanium systems. Methods and Materials: One hundred extracted human mandibular molars with two separated canals in mesial root were divided into five groups and prepared using Reciprocating systems (Reciproc file and Safesider endodontic reamers file), full rotary systems (Mtwo and Neoniti A1 files) and hand instrumentation systems. Endodontic access was prepared and a #15 K-file was passed beyond the apex of the mesiobuccal canal by 1 mm to ensure the canal patency. All mesiobuccal canals were prepared 1 mm shorter than the anatomic apex. In each case, extruded debris was collected in an Eppendorf tube and weighed after desiccation. The mean weight of extruded material was calculated in each group. The analysis was carried out using the Kruskal– Wallis test followed by two tailed and Mann-Whitney U test at a significance level of 0. 05. The Bonferroni correction was also applied to correct multiple comparisons. Results: There was a statistically significant difference between the reciprocal and other techniques in debris extrusion (P<0. 05). The order of groups ranked in terms of debris extrusion from the lowest to highest was as follows: 1) Hand instrumentation group (with crown down technique), 2) Mtwo group, 3) Neoniti A1 group, 4) Safesider endodontic reamer group, and 5) Reciproc group. Conclusion: Based on this in vitro study, all systems have some apical debris extrusion; however, using the hand instrumentation system resulted in extrusion of significantly less debris compared to the Reciproc group. It seems that hand and rotary instrumentation systems are better than Reciprocating instrumentation systems in terms of the amount of debris extrusion.