Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve (II) : Countermeasure of Water Hammer using Safety Valve

Takahashi, Kazuhiko; Inagaki, Hitone; Tasumi, Masahiro; Takeshita, Shinichi

doi:10.7132/jrcsa.kj00005702907

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…The flow rate of the division works Q is treated as an orifice by using the pressure difference ¨h between the upstream and downstream sides of the valve, and the area of the flow is assumed as constant, as shown in Eq. (13).…”

Section: Pressure Oscillation Due To Opening Rate Of the Valvementioning

confidence: 99%

“…Hence, they show advanced controlled performances for the pressure on the downstream side (secondary side), and necessary water-stop function is ensured. In addition, the verification of stability in the case where multiple pressure-reducing valves are placed in series and methods to suppress water hammer pressure using safety valves were studied experimentally, and some precautionary countermeasures are proposed (Inagaki et al, 1999;, Takahashi et al, 2009a2009b;.…”

Section: Introductionmentioning

confidence: 99%

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Self-excited Pressure Vibration in the Low-Pressure Pipeline Using an Automatic Pressure-reducing Valve (I)

Akiyoshi

Suzuki

Ito

et al. 2017

Journal of Rainwater Catchment Systems

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There is a case where a self-excited pressure variation is generated in low-pressure pipeline systems using an automatic pressure-reducing valve. For example, the pressure acting on the tube and valve is higher than the expected pressure and results in damage to the equipment. This study aims to explain the upstream and downstream pressure variations of the valve by carrying out pressure measurements in an actual pipe, in order to identify the mechanism of the self-excited variations and take effective countermeasures. For a reducing valve set up in the middle of the pipeline, the results indicated that the pressure variations that occur soon after opening the valve propagate upstream and downstream without attenuation, maintaining a constant amplitude, and generate continuing pressure variations that resemble self-excited oscillations. In addition, numerical simulations based on the wave model are conducted to evaluate the relationship between the response of an automatic pressure-reducing valve and the hydraulic transient phenomena in a pipeline system. If the pressure-reducing valve is adjusted for high-sensitivity, pressure variation due to external disturbances in the terminal region (downstream of the valve) may increase because of the period of pressure oscillation in the conduit of the upstream and downstream parts of a control valve.

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Section: Pressure Oscillation Due To Opening Rate Of the Valvementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-excited Pressure Vibration in the Low-Pressure Pipeline Using an Automatic Pressure-reducing Valve (I)

Akiyoshi

Suzuki

Ito

et al. 2017

Journal of Rainwater Catchment Systems

Self Cite

View full text Add to dashboard Cite

show abstract

Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve(IV)

Inagaki

Takahashi

Tasumi

et al. 2010

Journal of Rainwater Catchment Systems

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A field test was conducted on the stability of a pressure-reducing system combining a new type of automatic control valve in parallel with a conventional automatic control valve in a test pipeline in Ohno Mountain of Kagoshima Prefecture. The pressure control functions which include initiation of water flow and closing during transient conditions of increases and decreases in flow were investigated in a field experiment. The results were as follows: 1 When the conventional and new type automatic control valves are employed in parallel, and a safety valve is not used, the characteristics of the conventional valve take precedence. So when the flow is stopped, pressure builds up in the up-and downstream sides of the valves. 2 It is possible to combine the conventional and new type automatic control valves in a series installation. But when they are installed in parallel as a main valve and a bypass valve, respectively, countermeasure comprising concurrent installation of a safety valve to control the secondary side pressure of the control valves is needed. 3 The pressure control functions of conventional control valves are not as effective as the new type of control valve during stopped flow and very low-volume flows, so it is difficult to deal with changes in flow volume with an end valve. Furthermore, conventional control valves are slower in operation than the new type of control valve. Thus, if the conventional model is installed as the main valve in combination with the new model installed as the bypass valve, the system will no longer be dependent on the safety valve for control of secondary side pressure of the control valve. And with this, it will be possible to control the pressure in response to changes in flow rate.

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Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve (III) : In the Case of Automatic Control Valves installed in series

Takahashi

Inagaki

Tasumi

et al. 2010

Journal of Rainwater Catchment Systems

View full text Add to dashboard Cite

Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve (II) : Countermeasure of Water Hammer using Safety Valve

Cited by 4 publications

References 2 publications

Self-excited Pressure Vibration in the Low-Pressure Pipeline Using an Automatic Pressure-reducing Valve (I)

Self-excited Pressure Vibration in the Low-Pressure Pipeline Using an Automatic Pressure-reducing Valve (I)

Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve(IV)

Pressure Countermeasure Control on Pressure-reducing Pipeline System Using Safety Valve (III) : In the Case of Automatic Control Valves installed in series

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