Suction Box

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Martine Rueff - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the fiber water separation process through a Suction Box of a single wire pilot paper machine
    Separation and Purification Technology, 2012
    Co-Authors: Jeanclaude Roux, Martine Rueff
    Abstract:

    Abstract During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (Suction Boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredee’s formulation [1] was obtained. It states that, at a constant Suction pressure, the amount of filtrate per unit surface area is proportional to the square root of Suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the Suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted Suction Box of a Fourdrinier pilot paper machine. The Suction pressure was varied from 0.5 to 3.0 kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the Suction Box and on the Suction Box itself, the average specific filtration resistance which was 10 10  m kg −1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes.

  • Characterization of the fiber–water separation process through a Suction Box of a single-wire pilot paper machine
    Separation and Purification Technology, 2012
    Co-Authors: Jeanclaude Roux, Martine Rueff
    Abstract:

    Abstract During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (Suction Boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredee’s formulation [1] was obtained. It states that, at a constant Suction pressure, the amount of filtrate per unit surface area is proportional to the square root of Suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the Suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted Suction Box of a Fourdrinier pilot paper machine. The Suction pressure was varied from 0.5 to 3.0 kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the Suction Box and on the Suction Box itself, the average specific filtration resistance which was 10 10  m kg −1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes.

Jeanclaude Roux - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the fiber water separation process through a Suction Box of a single wire pilot paper machine
    Separation and Purification Technology, 2012
    Co-Authors: Jeanclaude Roux, Martine Rueff
    Abstract:

    Abstract During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (Suction Boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredee’s formulation [1] was obtained. It states that, at a constant Suction pressure, the amount of filtrate per unit surface area is proportional to the square root of Suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the Suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted Suction Box of a Fourdrinier pilot paper machine. The Suction pressure was varied from 0.5 to 3.0 kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the Suction Box and on the Suction Box itself, the average specific filtration resistance which was 10 10  m kg −1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes.

  • Characterization of the fiber–water separation process through a Suction Box of a single-wire pilot paper machine
    Separation and Purification Technology, 2012
    Co-Authors: Jeanclaude Roux, Martine Rueff
    Abstract:

    Abstract During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (Suction Boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredee’s formulation [1] was obtained. It states that, at a constant Suction pressure, the amount of filtrate per unit surface area is proportional to the square root of Suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the Suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted Suction Box of a Fourdrinier pilot paper machine. The Suction pressure was varied from 0.5 to 3.0 kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the Suction Box and on the Suction Box itself, the average specific filtration resistance which was 10 10  m kg −1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes.

Peter Åslund - One of the best experts on this subject based on the ideXlab platform.

Hannes Vomhoff - One of the best experts on this subject based on the ideXlab platform.

Rentian Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Influence of the bottom slab upward angle of elbow-type Suction Box on pumping system performance
    2014 ISFMFE - 6th International Symposium on Fluid Machinery and Fluid Engineering, 2014
    Co-Authors: Wei Zhou, Rentian Zhang
    Abstract:

    Elbow-type Suction Box is widely applied to China's large and medium-scale vertical pumping systems. The bottom slab of elbow-type Suction Box in the inlet segment can be horizontal or has an upward angle, the cross-sectional area of which is gradually contracted along the way from the inlet section to the outlet section and the flowing water is gradually accelerated. Characteristic of small hydraulic loss and better flow pattern that can generate better flow conditions for pump. One of the shortcomings of elbow-type Suction Box lies in that its height is larger compared with other type ones, resulting in deeper foundation excavation of pump house and greater civil construction investment. In pump station engineering practice, the bottom slab of elbow-type Suction Box is often designed to have an upward angle in the inlet segment in order to raise the bottom elevations of both forbay and sump, so that the height of their wing walls can be reduced and the quantity of earth excavation and concrete works of the pump house foundation can be lessened. Based on a design case of a certain pump station in China, three optimized design schemes of an elbow-type Suction Box with different bottom slab upward angles were put forward, and the method of computational fluid dynamics was adopted to simulate the internal flow of pumping systems with different Suction Boxes to analyze the influence of bottom slab upward angle on flow conditions of pump in terms of internal flow patterns, hydraulic loss, distribution uniformity of outlet axial velocity and bias angle of outlet flow field. The numerical simulation results indicate that the upward angle of bottom slab can be regulated within a certain range, which mainly affects the average velocity of inlet section and the hydraulic loss of inlet segment, and slightly affects the distribution uniformity of outlet axial velocity, bias angle of outlet flow field and pumping system efficiency.

  • Numerical Simulation of the Internal Flow of a New-Type Shaft Tubular Pumping System
    2012
    Co-Authors: Honggeng Zhu, Longyang Dai, Guoxian Zhu, Linbi Yao, Rentian Zhang, Jianqin Luo
    Abstract:

    The structural features of a pumping system will directly affect the investment of the pumping station and its pumping efficiency. In the design and construction of low head or extra-low head pumping stations, bulb tubular pumping system and shaft tubular pumping system are widely adopted. So far all the 5 large tubular pumping stations finished or under construction took the form of rear type bulb tubular pumping system (bulb is arranged inside the discharge passage) in China's Eastern Route Project of South-to-North Water Diversion. However, front type shaft tubular pumping systems (shaft is arranged inside the Suction Box) are more widely used in city flood-control pumping stations, which are characteristic of large amounts and medium or small scale. To improve the reliability of city flood-control pumping stations, the authors have invented a new-type shaft tubular pumping system featuring shaft Suction Box, siphon-type discharge passage with vacuum breaker valve as the cutoff device, which is possessed of such advantages as simpler structure, reliable cutoff and better energy performance. Taking an real pumping station in Yancheng city of China as an example, the computational fluid dynamics method was adopted in this paper to simulate the three dimensional turbulent flow of a model new-type tubular pumping system (impeller diameter D=0.3m, rotational speed n=1100r/min and specific speed ns is about 1500) and predict its performance, to improve the pumping system efficiency through hydraulic design optimization. Computation results show that the efficiency of the new-type shaft tubular pumping system reached 56.0% when the design head and discharge are 1.15m and 0.326m 3 /s respectively, and up to 68.8% when the maximum head and relevant discharge are 1.95m and 0.296m 3 /s respectively, having more extensive foreground for low-head, especially extra-low-head city flood-control pumping stations. Copyright © 2011 by ASME.

  • Numerical Analysis of Shaft Tubular Pumping Systems
    2011 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring, 2011
    Co-Authors: Rentian Zhang
    Abstract:

    In order to supply better flow conditions for pump and improve pumping system efficiency, numerical simulations were conducted in this paper on 3 design schemes of a shaft tubular pumping system to compare their energy performances and investigate the relationship between the design scheme and the system characteristics. With the same design of Suction Box and discharge passage, the head losses of the outlet discharge passage and the pumping system efficiencies were compared between 2 design schemes of different size and shape of the shaft (pit). The flow conditions of pump, in terms of distribution uniformity of axial velocity and velocity-weighted bias angle of outflow field in the outlet cross-section of Suction Box, and the pumping system efficiencies were compared between the front and rear arrangement of the shaft while keeping the shaft and the pump unchanged. The computational results show that for the rear arrangement of shaft schemes the size and shape of the shaft affect not only the head loss of the discharge passage but also the pumping system efficiency. If just simply turning the pump around 180 degrees without changing pump and flow passages, the pumping system can be operated both in the rear arrangement scheme of shaft and front arrangement scheme. However, the flow conditions of pump become deteriorated in terms of distribution uniformity and bias angle when the rear arrangement scheme of shaft changed to front arrangement. As a result, the hydraulic losses of Suction Box and discharge passage in front arrangement increases, the best efficiency point drops and high efficiency zone moves toward smaller flow rates.

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