Instability of System Caused by Hydraulic Machinery

2013 ◽  
pp. 377-429
Author(s):  
Yulin Wu ◽  
Shengcai Li ◽  
Shuhong Liu ◽  
Hua-Shu Dou ◽  
Zhongdong Qian
Keyword(s):  
Hydraulic Machinery

The Hydraulic Operation of Lathes for the Production of Shells

1944 ◽  
Vol 151 (1) ◽  
pp. 70-86
Author(s):  
W. Littlejohn Philip
Keyword(s):  
Machine Tools ◽  
Hydraulic Power ◽  
The Third ◽  
Hydraulic Machine ◽  
Hydraulic Machinery ◽  
Simple Machines ◽  
High Level ◽  
Shell Production ◽  
Hydraulic Operation ◽  
Made In

The paper is limited to the application of hydraulic power to lathes designed for shell making although, in the author's opinion, there is an immense field for the application of the same principles in other directions. Self-contained hydraulic machine tools have been dealt with by Mr. H. C. Town,† but in the system to be described all the machines are operated from a central hydraulic plant. Three complete installations on this principle have been established by the author, and the present paper contains an account of this work from the first experiments in 1915 until about four years ago. The first plant was constructed in 1915 for the production of 3·29-inch shells, known as “18-pounders”, from the solid bar. The output was 2,000 shells per week of 135 hours, with girl operators working on three shifts. The second plant was put down in 1916–17 for an output of 500 9·2-inch howitzer shells per week of 135 hours, also with girls working on three shifts. The third plant is of recent design. It was started in 1938 for the production of 3·45-inch shells, known as “25-pounders”; and was laid out for an output of 1,000 shells per week of 47 hours. This plant included four types of hydraulic lathes which the author was engaged to design for the War Office. Soon after the commencement of the last war in 1914 it became evident that shell production would have to be greatly increased, and engineering firms were pressed to take up shell manufacture. The author, on behalf of his firm, undertook to help in the movement, and he at once set about the construction of some simple machines for the job. These conformed on general lines to the practice of the period as regards design and operation. He soon realized, however, that drastic changes would have to be made if production was to reach the high level that circumstances demanded. Although quite familiar with hydraulic machinery of various types and of many applications in presses and certain types of heavy tools, he was not aware of any instance in which hydraulic power had been applied to the movements of a lathe. It appeared to him, nevertheless, that it would be possible to construct a very useful machine on these lines, and he accordingly started immediately to carry out experiments and to prepare designs. It was considered essential that machines for the duty which the author had in mind should be much heavier and more rigid than the ordinary machines of the time, so that they should be free from vibration and “chatter” or spring with the heaviest possible cutting. The standard of rigidity aimed at was that which would permit a half-crown coin to remain balanced on edge on the moving saddle or turret while the tools were making the heaviest cuts. This object was achieved, and the demonstration was frequently made in the presence of those who came to see the lathes at work.

scholarly journals Fiber Bragg Grating Sensors for Underwater Vibration Measurement: Potential Hydropower Applications

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4272
Author(s):  
Oscar de la Torre ◽  
Ignazio Floris ◽  
Salvador Sales ◽  
Xavier Escaler
Keyword(s):  
Fiber Bragg Grating ◽  
Numerical Models ◽  
Vibration Measurement ◽  
Quality Data ◽  
Bragg Grating ◽  
Laser Vibrometer ◽  
Main Concern ◽  
High Expectations ◽  
Fiber Bragg Grating Sensors ◽  
Hydraulic Machinery

The present paper assesses the performance and characteristics of fiber Bragg grating sensors, with a special interest in their applications in hydraulic machinery and systems. The hydropower industry is turning to this technology with high expectations of obtaining high quality data to validate and calibrate numerical models that could be used as digital twins of key assets, further strengthening the sector’s relevant position within industry 4.0. Prior to any validation, fiber Bragg grating sensors’ ability to perform well underwater for long periods of time with minimal degradation, and their ease of scalability, drew the authors´ attention. A simplified modal analysis of a partially submerged beam is proposed here as a first step to validate the potential of this type of technology for hydropower applications. Fiber Bragg grating sensors are used to obtain the beam’s natural frequencies and to damp vibrations under different conditions. The results are compared with more established waterproof electric strain gauges and a laser vibrometer with good agreement. The presence of several sensors in a single fiber ensures high spatial resolution, fundamental to precisely determine vibration patterns, which is a main concern in this industry. In this work, the beam’s vibration patterns have been successfully captured under different excitations and conditions.

Structural Dynamic Analysis in Hydraulic Machinery

2013 ◽  
pp. 277-304 ◽  
Author(s):  
Yulin Wu ◽  
Shengcai Li ◽  
Shuhong Liu ◽  
Hua-Shu Dou ◽  
Zhongdong Qian
Keyword(s):  
Dynamic Analysis ◽  
Structural Dynamic ◽  
Hydraulic Machinery

Ninth Circuit Nursery

2021 ◽  
pp. 171-207
Author(s):  
Steven W. Usselman
Keyword(s):  
West Coast ◽  
Textual Analysis ◽  
Patent Law ◽  
Oil Drilling ◽  
Ninth Circuit ◽  
Circuit Court ◽  
Court Of Appeals ◽  
Federal Judiciary ◽  
Hydraulic Machinery ◽  
Appeals Court

Based on statistical and textual analysis of the 148 patent cases heard by the Ninth Circuit Court of Appeals from its creation through 1925, this chapter suggests that the appeals judges created a legal environment highly favorable to innovative West Coast enterprises. Their rulings consistently sided with local patent holders and alleged infringers over litigants from outside the circuit. Cases involving only local parties produced more mixed results, as judges sought to mediate disputes among competing regional suppliers, while insulating small proprietors from risks of infringement. Through these means, the appeals court actively shaped competition and influenced the course of innovation in such emergent fields as oil drilling and refining, hydraulic machinery, and food processing. The distinctiveness of Pacific Coast patent law diminished after 1915 under influence of a federal judiciary stacked with protégés of ex-President William Howard Taft, who became Chief Justice in 1921.

scholarly journals Three-Dimensional Inverse Design Method for Hydraulic Machinery

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3210
Author(s):  
Wei Yang ◽  
Benqing Liu ◽  
Ruofu Xiao
Keyword(s):  
High Performance ◽  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
Blade Loading ◽  
Hydraulic Machinery ◽  
Main Challenge ◽  
Blade Shape ◽  
Stacking Condition ◽  
Inverse Design Method

Hydraulic machinery with high performance is of great significance for energy saving. Its design is a very challenging job for designers, and the inverse design method is a competitive way to do the job. The three-dimensional inverse design method and its applications to hydraulic machinery are herein reviewed. The flow is calculated based on potential flow theory, and the blade shape is calculated based on flow-tangency condition according to the calculated flow velocity. We also explain flow control theory by suppression of secondary flow and cavitation based on careful tailoring of the blade loading distribution and stacking condition in the inverse design of hydraulic machinery. Suggestions about the main challenge and future prospective of the inverse design method are given.

scholarly journals Replacement and Maintenance Decision Analysis for Hydraulic Machinery Facilities at Reservoirs under Imperfect Maintenance

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2507
Author(s):  
Sou-Sen Leu ◽  
Tao-Ming Ying
Keyword(s):  
Cost Effective ◽  
Maintenance Cost ◽  
Imperfect Maintenance ◽  
Term Operation ◽  
Engineering Economics ◽  
Hydraulic Machinery ◽  
Effective Manner ◽  
The Cost ◽  
Replacement Time

After the long-term operation of reservoir facilities, they will become nonoperational due to the material deterioration and the performance degradation. One of crucial decisions is to determine the maintenance or replacement of the facilities in a cost-effective manner. Conventional replacement models seldom consider the maintenance effect. The facilities after maintenance are generally not as good as new, but are relatively restored. The target of this study is to establish a replacement decision model of the reservoir facilities under imperfect maintenance. By combining the theories of reliability analysis, imperfect maintenance, and engineering economics, the best timing of replacement that achieves cost-effectiveness is analyzed and proposed. Lastly, based on the design of experiments (DOE) and simulation, the regression curve chart for the economical replacement decision is established. Once the failure rate, the age of recovery after maintenance, and the ratio of maintenance cost to replacement cost are estimated based on historical data, the cost-effective replacement time of hydraulic machinery facilities will be efficiently determined.

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