• Corrosion Science and Technology
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• v.14 no.2
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• pp.93-98
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• 2015

Recently, Stainless steels have been increasingly selected as the fitting or the valve materials of water pipes as the human health issue is getting higher and higher. Therefore, the connectors attached at pipes to deliver water are exposed to more severe environments than the pipes because crevice or galvanic corrosion is apt to occur at the fittings or the valves. Effects of the solid solution annealing, cooling rate after this heat treatment, and passivation on the corrosion properties of the shell mold casted SSC13 (STS304 alloy equivalent) were studied. The heating and quenching treatment more or less reduced hardness but effectively improved corrosion resistance. It was explained by the reduction of delta ferrite contents. Independent of heat treatment, the chemical passivation treatment also lowered corrosion rate but the improvement of corrosion resistance depended on temperature and time for passivation treatment indicating that the optimum conditions for passivation treatment were the bath temperature of $34^{\circ}C$ and operating time of 10 minutes. Therefore it is suggested that the corrosion resistance of SSC13 can be effectively improved with the heat treatment, where SSC13 is heated for 10 minutes at $1120^{\circ}C$ and quenched and passivation treatment, where SSC13 is passivated for at least 10 seconds at $34^{\circ}C$ nitric acid solution.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.74-81
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• 2018

The Korean Government has proceeded petroleum gas pipeline construction business since 2014 for rural districts. The operating pressure of petroleum gas pipeline are from 25kPa to 75kPa which are different from that of natural gas pipeline. Petroleum gas pipeline pressure is ten or forty times higher than natural gas operating pressure. For this reason, petroleum gas pipeline has higher probability of accident occurrence from massive gas leakage. Korea Gas Safety Corporation begins to development excess flow valves and their performance testing equipment since 2017. The excess flow valves stop the gas flow when a overflow happened in gas pipeline. The excess flow valves are generally not installed in main pipeline, because that may block massive gas supply. So, the valves are installed in starting points of branch pipes. According to the number of house and amount of gas use, a shut-off point of exxcess flow valve is determined called as Trip Flow. The trip point is the most important thing of excess flow valve, so, it is required a equipment testing the performances of excess flow valve as trip point.

• Journal of Korea Water Resources Association
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• v.42 no.6
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• pp.505-511
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• 2009

When replacing deteriorated pipes, it is important to select pipe diameters of new pipes for improving the long-term reliability of a water distribution system. However, as the use of larger diameter pipes brings cost increase, it is required to evaluate the improvement of the reliability by the use of larger diameter pipes. In this study, we propose a methodology to evaluate the improvement of the reliability by the use of different pipe diameters. For this purpose, we rely on the segment-based minimum cutset method with the success mode approach to evaluate the reliability of a water distribution system and determine which pipes and their diameters will be replaced to improve the reliability using GA, After the suggested method is applied to a real water distribution system, the optimized pipe diameters produces higher reliability of the system than the current ones with the same construction cost. However, compared to the increase rate of the construction cost, the improvement of the reliability is not significant. Thus, in addition to the use the different pipe diameters, the structural modification or adding new valves to the system is necessary to improve the reliability efficiently.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.70-78
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• 2000

A balanced vane pump for the use of automotive power steering systems generates a flow ripple which is imposed upon the mean flow rate. The flow ripple interacts with the characteristics of the connected pipes, valves and steering gear in a complex manner to produce a pressure ripple, also known as fluid-borne noise. In order to reduce vibration level and produce quieter and more reliable power steering systems, it is important to measure the flow ripple produced by a pump with high accuracy and fast response. In this paper, the flow ripple generated by a vane pump in automotive power steering systems is measured by the remote instantaneous flow rate measurement method (RIFM) using hydraulic pipeline dynamics. In experiment, flow and pressure ripple wave forms are measured under various operating conditions. Also, the parameters affected upon the flow and pressure ripple are investigated by the frequency analysis.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.602-609
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• 2011

In this paper, we standardized the water operation system picture, process control logic, realtime database and system configuration. All aspects, including monitoring & controlling processes, symbols such as pumps, valves and pipes were standardized. As a result we have developed a specialized Integrated water operation system, iWater. We have developed a variety of advanced application programs that are essential for water treatment systems, such as IWS (Integrated Warning system), MBO(modbus opc)/LSE(LS ethernet) driver, video monitoring, self diagnosis system, network monitoring, etc. IWS prevents water supply accidents by using a variety of alarms and warning messages. Drivers have the flexibility to communicate with other 3rd party systems. We expect that iWater will eliminate any concerns regarding water-related issues while also promoting the production and fair distribution of clean water.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1897-1904
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• 2002

Monotonic torsional and pure torsional low cycle fatigue(LCF) test with artificial degradation were performed on duplex stainless steel(CF8M). CF8M is used in pipes and valves in nuclear reactor coolant system. It was aged at 430$^{\circ}C$ for 3600hrs. Through the monotonic and LCF test, it is found that mechanical properties(i.e., yield strength, strain hardening exponent, strength coefficient etc.) increase and fatigue life(N$\sub$f/) decreases with degradation of material. The relationship between shear strain amplitude(${\gamma}$$\sub$a/)and N$\sub$f/ was proposed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.815-823
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• 1999

A dynamic simulation program may be used for the development of effective control algorithms for the ice storage cooling system. Simplified effective dynamic models for an ice-on-coil type storage tank, a screw chiller, a water-to-air heat exchanger, three way valves, pipes, pumps, temperature sensors, and controllers were developed. And a dynamic simulation program for the ice storage cooling system was developed by using these dynamic models. Control algorithms for the full storage system were also selected and analyzed in order to show the effectiveness of these models. From the simulation results, it may be concluded that the simulation program developed in this study can be effectively used for the development of improved control algorithms for the ice storage cooling system.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1760-1764
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• 2003

This study was carried out to establish an analytical method on the open circuit seawater pipeline network for open rack vaporizers(ORVs). The linear theory method was chosen to solve this network system. In particular, the method was modified to calculate the static pressure at each node and to determine the operating condition of each pump with the mean static pressure of pumps and ORVs. The proposed method is the first report demonstrating that can be used as a solver for the complicated open circuit. Also, the method indicated the importance for exactly calculating equivalent length of pipes including valves, bends, fittings, and others to raise the accuracy. Although this technique is good for solving this system, it is still required to improve the convergence rate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.79-84
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• 2010

The supply system module of the liquid rocket engine has been developed, which consists of the various supply system components such as pipes, orifices, elbows, bellows, valves and flanges. This module can size the components and calculate pressure drops between them. For the assembly of the supply system components, the supply system module can evaluate the number of the components, total pressure drop, outlet pressure and total system weight.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1187-1195
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• 2022

To run the algorithm for identifying the segments of a pipe network, the relative positional relation between nodes, pipes, and valves should be prepared as input information of a segment search algorithm. In order to more accurately identify the segments of real pipe network, pipe network GIS/CAD database that contains all isolation valves is more suitable than modeled pipe network information used for a hydraulic analysis program. In this study, we developed an algorithm that can establish the relative positional relations among node-pipe-valve suitable for pipe network segment search algorithms using GIS/CAD data of a real water supply network, and developed a MATLAB program that can implement it. The effectiveness of the developed MATLAB program was confirmed by applying it to a portion of a real municipal pipe network.