• Title/Summary/Keyword: 수도용 밸브

Search Result 11, Processing Time 0.034 seconds

Study on Vibration Induced by Fluid at a Water Pressure Reducing Valve through Structure-Fluid Coupled Analysis (구조-유체 연성해석을 통한 수도용 감압밸브에서의 유체유발진동에 관한 연구)

  • Park, Woo-Cheul;Lee, Joong-Kuen;Kim, Il-Gyoum;Park, Yong-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.13 no.10
    • /
    • pp.4371-4377
    • /
    • 2012
  • In this paper, the structure-fluid coupled analysis is carried out in order to examine the cause of the vibration induced by fluid in the pressure-reducing valves for water. It is confirmed that there is the noise at the area of low frequency of 250Hz by measuring noise at pressure reducing valve. The flow analysis is performed by the commercial software ANSYS/CFX. The flow velocity of about 40 m/s is formed by nozzle effect, and so negative pressure is happened in the pressure reducing valve. The structure analysis is carried out with the load condition of pressure distribution by flow formed in valve. The rubber material at disk is deformed to the extent of closing up flow passage. It is confirmed that the disc deformation which is occurred repeatedly is due to noise and vibration at the pressure reducing valve.

Structural safety evaluation of decrepit gray cast iron water valves for the control of water supply (노후 회주철 수도용 제수밸브의 구조적 안전성 평가)

  • Lee, Ho-Min;Choi, Tae-Ho;Park, Jeong-Joo;Bae, Cheol-Ho
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.36 no.5
    • /
    • pp.261-273
    • /
    • 2022
  • In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

A study on the condition assessment of large diameter water valves using non-destructive technologies (비파괴 기술을 이용한 대구경 수도용 밸브의 상태평가에 관한 연구)

  • Ho-Min Lee;Hyun-yong Choi;Suwan Park;Tae-min Oh;Chae-Min Kim;Cheol-Ho Bae
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.37 no.4
    • /
    • pp.215-229
    • /
    • 2023
  • In this study, non-destructive technologies that can be applied to evaluate the integrity of valve materials, safety against internal pressure caused by corrosion, and the blocking function of large-diameter water valves during operation without requiring specimen collection or manpower entering the inside of the valve were tested to assess the reliability of the technologies and their suitability for field application. The results showed that the condition of the graphite structure inside the valve body can be evaluated directly through the optical microscope in the field without specimen collection for large-diameter water butterfly valves, and the depth of corrosion inside the valve body can be determined by array ultrasound and the tensile strength can be measured by instrumented indentation test. The reliability of each of these non-destructive techniques is high, and they can be widely used to evaluate the condition of steel or cast iron pipes that are significantly smaller in thickness than valves. Evaluation of blocking function of the valves with mixed gas showed that it can be detected even when a very low flow rate of mixed gas passes through the disk along with the water flow. Finally, as a result of evaluating the field applicability of non-destructive technologies for three old butterfly valves installed in the US industrial water pipeline, it was found that it is possible to check the material and determine the suitability of large-diameter water valves without taking samples, and to determine the corrosion state and mechanical strength. In addition, it was possible to evaluate safety through the measurement results, and it is judged that the evaluation of the blocking function using mixed gas will help strengthen preventive response in the event of an accident.

Plate Type New Distributor Development for Hydraulic Motors and Pumps (유압모터 및 펌프용 판 형태의 새로운 분배기 개발)

  • Jin, Seong-Mu;Kim, Hyeong-Ui
    • 한국기계연구소 소보
    • /
    • s.18
    • /
    • pp.75-85
    • /
    • 1988
  • The distributor for hydraulic pumps or motors, particularly radial piston motors, include rotary member which has equally both surface shape for dynamic balance and two fixed members, located in both side of rotary member, which have equal surface shape for dynamic balance and circular ring which use to retain predetermined clearance between two fixed members. Rotary member must have valve part for flow-distribution and can have hydrostatic bearing for excellently dynamic balance. At least two annular steps located on said pressure plate which use in compensation of bolt expansion.

  • PDF

FE Analysis on the Screwed Safety of a Valve for a LPG Bombe (LPG 용기용 밸브의 체결안전성에 관한 유한요소해석)

  • Kim, Chung-Kyun;Oh, Kyong-Seok
    • Journal of the Korean Institute of Gas
    • /
    • v.11 no.4
    • /
    • pp.79-84
    • /
    • 2007
  • In this paper, the finite element analysis of a valve screw for a LPG cylinder has been presented on the leakage safety and strength one, which are computed and investigated by a contact normal stress and von Mises stress between a female screw of a valve and a male screw of a neck ring in a LPG bombe. The LP gas charging pressure of a LPG bombe is $8{\sim}9kg/cm^2$, which is pressurized to the screw sealing contact areas between a valve and a LP gas cylinder. The peak failures of the screw tooth height due to a scratch wear and chipping loss of the contact area may decrease screw tooth strength and increase a leakage of a LP gas. These are strongly affect to the contact normal and von Mises stresses of the valve screws. The FEM computed results show that the tooth height loss due to a wear and chipping failure of the screw peak does not affect to the LP gas leak and strength of a valve screw theoretically. But if the tooth wear of the screw height of a brass valve overpasses the critical strength safety of the valve, the valve screw may be failed in fastening the valve and a LP gas bombe suddenly.

  • PDF

Evaluation of Seismic Performance of Valve Chamber System by Shaking Table Tests (진동대 실험을 통한 밸브실 시스템의 내진성능 평가)

  • Young-Soo Jeong;Kyeong-Seok Lee;Jin-Seok Yu;Hyung-Chae Jeong
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.28 no.1
    • /
    • pp.46-52
    • /
    • 2024
  • The structural safety of expansion joints for piping systems has been drawing attention owing to ruptures and leaks of water pipes caused by earthquakes and road subsidence at soft ground. In general, metal bellows are installed as expansion joints to prevent various damages in the piping system. In this study, the seismic performance of a valve chamber system was evaluated by performing earthquake shaking table tests. To validate the benefits to structural safety of metal bellows in connecting steel pipes to valve chambers, the seismic tests were conducted on expansion joints (bellows) and general pipping, and the results were compared for durability. Strain gauges were attached to measure the effects of the input motion. As a result of the shaking table test, it was confirmed that the strain of the valve chamber structure and inflow or outflow steel pipes were decreased in 1/100, 1/20 by applied to the expansion joints.