scholarly journals Simulation of hydraulic pump load in laboratory conditions

2021 ◽  
Vol 351 ◽  
pp. 01005
Author(s):  
Ľubomír Hujo ◽  
Romana Janoušková ◽  
Štefan Čorňák ◽  
Juraj Tulík

The aim of the scientific contribution is simulating the load of gear hydraulic pump used in agricultural machinery in laboratory conditions, where the impact of ecological transmission-hydraulic fluid on life limit (flow and efficiency) of gear hydraulic pump GHD1-17R is monitored. Laboratory test equipment was used for the simulation. The equipment was used to perform life limit test of hydraulic pump and to monitor changes in physicochemical ecological energy carriers. The simulation in laboratory conditions took 500 hours. The Vickers test took 100 hours. Transmission-hydraulic fluid MOL Farm NH Ultra was used for simulation. The results were that fluid is appropriate to use in this type of hydraulic pump in agricultural machineries. According to the Vickers test, the fluid is characterized by an increased value of flow and efficiency after 50 working hours, thereby exceeding the specified test values.

Author(s):  
Sandra Mrvica Mađarac ◽  
◽  
Marko Eljuga ◽  
Zvonimir Filipović ◽  
◽  
...  

The entire world is facing with the impact and consequences of the COVID 19 pandemic, what is reflected in various spheres of social life. In the conditions of the crisis management, companies are forced to adapt to the new situation in order to survive on the market. Sales companies have had to make changes in their former business; namely in their organization, logistics, retail supply channels that are now oriented towards the online sales without contact when delivering to customers. The Civil Protection Headquarters of the Republic of Croatia has brought a Decision by which are regulated the working hours and the method of work in the trade business during the Coronavirus epidemic, according to which it is obligatory for all stores to organize their work in compliance with general anti-epidemic measures and special recommendations of the Croatian Institute of Public Health. In the paper are listed and analyzed changes in the sales operations of the two companies due to the pandemic crisis; one company deals with the sale of agricultural machinery and the other with the sale of food products.


2013 ◽  
Vol 801 ◽  
pp. 7-12 ◽  
Author(s):  
Ján Kosiba ◽  
Ľubomír Hujo ◽  
Juraj Tulík ◽  
Milan Rašo

This paper deals with the lifetime test of a tractor hydraulic pump. The basic indicator of hydraulic pump lifetime is flow characteristics. This paper presents the results of the performance test of ecological hydraulic fluid. These results were subjected to statistical analysis. Based on these data, it is possible to express a minimum impact of ecological hydraulic fluid on hydraulic pump lifetime. The test was carried out in cooperation between the Department of Transport and Handling (Slovak University of Agriculture in Nitra) and Slovnaft, a.s. (joint-stock company), and supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic – VEGA, ref. No 1/0857/12.


2021 ◽  
Vol 54 (3-4) ◽  
pp. 243-251
Author(s):  
Lubomir Hujo ◽  
Jozef Nosian ◽  
Marcin Zastempowski ◽  
Jan Kosiba ◽  
Jerzy Kaszkowiak ◽  
...  

The present article deals with the physical properties monitoring of the transmission-hydraulic fluid, and changes of those properties due the operating load of the hydraulic pump in laboratory conditions. Tests of the transmission-hydraulic fluid were performed in laboratory conditions with the simulation of the operating load, so as to simulate the real conditions under which hydraulic circuit of the agricultural tractors operates. The universal transmission-hydraulic fluid was subjected to analysis, where the samples of the fluid were taken sequentially according to the chosen methodology at intervals of 250 and 500 h. The results of the present article include the evaluation of the physical properties of the fluid and the flow efficiency change of the hydraulic pump after 250 and 500 h of operation, while simulating the operation load. Based on a laboratory test, we found that after working for 500 h, the dynamic viscosity of the examined hydraulic fluid at 40°C decreased by 2.92 mPa.s and at 100°C decreased by 0.64 mPa.s. When determining the kinematic viscosity of the hydraulic fluid after working for 500 h, we recorded its decrease, namely, at a temperature of 40°C by a value of 3.37 mm2/s and at a temperature of 100°C, its value decreased by 0.77 mm2/s. In the analysis of the test oil samples, we found that the level of water contamination of the hydraulic fluid decreases with increasing number of hours worked. Specifically, the water concentration in the hydraulic fluid decreased by 0.031%. At the same time, we recorded a slight decrease in the flow efficiency of the hydraulic pump, specifically by a value of 0.03% after 500 h worked. After working 500 h, we found that the range of abrasion particles in the transmission-hydraulic fluid is within the prescribed range, which is determined by the standard D6595-00.


2019 ◽  
Vol 302 ◽  
pp. 01006
Author(s):  
Romana Janouskova ◽  
Jerzy Kaszkowiak ◽  
Marek Halenar ◽  
Martin Zachar ◽  
Jozef Nosian

The focus of this sceintific article is a laboratory research on the qualities of environmental energy carriers by simulating the operational load, focusing on changes of physico-chemical qualities of ecological hydraulic and transmission fluid used in agricultural tractors. In laboratory setting by using a simulator, it was possible to simulate different operational load and also track changes in qualities of hydraulic fluid by changing the flow in precise intervals. The hydraulic-transmission fluid used in the laboratory setting was the MOL Farm NH Ultra.


2014 ◽  
Vol 1059 ◽  
pp. 111-117
Author(s):  
Zdenko Tkáč ◽  
Ján Kosiba ◽  
Ľubomír Hujo ◽  
Daniela Uhrinová ◽  
Ivan Štulajter

Hydraulic pumps are the most important components of hydraulic circuits in agricultural tractors. Their durability is influenced by flow characteristics and thus the flow efficiency. This paper presents the laboratory test of an ecological synthetic hydraulic fluid of UTTO type. This fluid is currently under development. In terms of a decrease in hydraulic pump flow efficiency, laboratory tests of these fluids did not show negative effects of its application. It can be stated that after completion of laboratory tests, it will be needed to continue with trials under operational conditions.


Author(s):  
Z Tkáč ◽  
Š Čorňák ◽  
J Kosiba ◽  
R Janoušková ◽  
M Michalides ◽  
...  

This article deals on the impact of the ecological hydraulic fluid type hydraulic environmental ester synthetic oil on operation of mini excavator hydraulic circuit. An operational test was to 500 engine hours. Hydraulic fluid is evaluated for chemical contamination. Fluid samples were taken from the mini excavator at 250 engine hours intervals. These samples were subjected to IR spectroscopic analysis, kinematic viscosity measurements at 40° C and 100° C, total acid number measurement and differential scanning calorimetry. It was found that the ecological hydraulic oil does not influence the operation of the mini excavator. Based on the achieved results, it was shown that the degradation processes during the operational test of the ecological fluid do not affect the operating parameters of the monitored machine. The presented paper also presents the results of the influence of hydraulic on the flow characteristics of the hydraulic pump.


2020 ◽  
Vol 11 (05) ◽  
pp. 857-864
Author(s):  
Abdulrahman M. Jabour

Abstract Background Maintaining a sufficient consultation length in primary health care (PHC) is a fundamental part of providing quality care that results in patient safety and satisfaction. Many facilities have limited capacity and increasing consultation time could result in a longer waiting time for patients and longer working hours for physicians. The use of simulation can be practical for quantifying the impact of workflow scenarios and guide the decision-making. Objective To examine the impact of increasing consultation time on patient waiting time and physician working hours. Methods Using discrete events simulation, we modeled the existing workflow and tested five different scenarios with a longer consultation time. In each scenario, we examined the impact of consultation time on patient waiting time, physician hours, and rate of staff utilization. Results At baseline scenarios (5-minute consultation time), the average waiting time was 9.87 minutes and gradually increased to 89.93 minutes in scenario five (10 minutes consultation time). However, the impact of increasing consultation time on patients waiting time did not impact all patients evenly where patients who arrive later tend to wait longer. Scenarios with a longer consultation time were more sensitive to the patients' order of arrival than those with a shorter consultation time. Conclusion By using simulation, we assessed the impact of increasing the consultation time in a risk-free environment. The increase in patients waiting time was somewhat gradual, and patients who arrive later in the day are more likely to wait longer than those who arrive earlier in the day. Increasing consultation time was more sensitive to the patients' order of arrival than those with a shorter consultation time.


Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 466
Author(s):  
Xi Yu ◽  
Xiyang Yin ◽  
Yuying Liu ◽  
Dongmei Li

Agricultural machinery services play an increasingly important role in the land transfer market, especially in developing countries. Prior studies have explored the impact factors of machinery use on agricultural production and land transfer, respectively. However, little research has focused on the relationship between the adoption of agricultural machinery services and the land transfer of rice farmers. To bridge this gap, this study investigated the correlation between machinery services and land transfer, using unique survey data of 810 rice farmers collected from Sichuan province in China. Additionally, this study further explored the impact mechanism on land transfer of rural households with IV-Probit and IV-Tobit models. The empirical results show the following: (i) Agricultural machinery services have a significantly positive and robust effect on both the incidence and area of rice farmers’ land transfer-in, while the impact degree is different. Specifically, with other conditions remaining unchanged, and with a 1% increase in the proportion of machinery services, the average probability of land transfer-in of rice farmers increased by 2.4%, and the area of land transfer-in increased by 13.4 mu, on average. (ii) For control variables, head education, agricultural certificates and whether the majority of land, are in a flat area have positive impacts on land transfer-in behavior. Yet, age and off-farm labor have a negative impact on land transfer-in area. Moreover, our findings highlight the importance of agricultural machinery services in stimulating the development of rural land rental markets.


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