{"id":1231,"date":"2026-10-07T07:27:51","date_gmt":"2026-10-07T07:27:51","guid":{"rendered":"https:\/\/wdlvalve.com\/?p=1231"},"modified":"2026-10-07T07:30:42","modified_gmt":"2026-10-07T07:30:42","slug":"%e0%b8%a7%e0%b8%b2%e0%b8%a5%e0%b9%8c%e0%b8%a7%e0%b8%84%e0%b8%a7%e0%b8%9a%e0%b8%84%e0%b8%b8%e0%b8%a1%e0%b8%81%e0%b8%b2%e0%b8%a3%e0%b9%84%e0%b8%ab%e0%b8%a5%e0%b8%82%e0%b8%ad%e0%b8%87%e0%b8%81%e0%b8%a3","status":"publish","type":"post","link":"https:\/\/wdlvalve.com\/th\/%e0%b8%a7%e0%b8%b2%e0%b8%a5%e0%b9%8c%e0%b8%a7%e0%b8%84%e0%b8%a7%e0%b8%9a%e0%b8%84%e0%b8%b8%e0%b8%a1%e0%b8%81%e0%b8%b2%e0%b8%a3%e0%b9%84%e0%b8%ab%e0%b8%a5%e0%b8%82%e0%b8%ad%e0%b8%87%e0%b8%81%e0%b8%a3\/","title":{"rendered":"\u0e27\u0e32\u0e25\u0e4c\u0e27\u0e04\u0e27\u0e1a\u0e04\u0e38\u0e21\u0e1b\u0e23\u0e34\u0e21\u0e32\u0e13\u0e01\u0e23\u0e30\u0e14\u0e32\u0e29 (Ventil Papierstoffmengenregelung): \u0e04\u0e39\u0e48\u0e21\u0e37\u0e2d\u0e01\u0e32\u0e23\u0e40\u0e25\u0e37\u0e2d\u0e01"},"content":{"rendered":"

Quick answer:<\/strong> \u201cVentil Papierstoffmengenregelung\u201d describes a valve used to regulate the quantity or flow of paper stock. In a paper machine approach-flow or stock-preparation system, this valve helps stabilize pulp flow, consistency and basis weight. Accurate selection depends on stock consistency, fiber characteristics, flow range, differential pressure, valve geometry and actuator resolution.<\/p>\n

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A paper stock flow control valve<\/strong> handles a mixture of cellulose fibers, water and process additives. This medium does not always behave like clean water. Fibers can form networks, collect in narrow passages and change the effective flow capacity of a valve. A reliable specification therefore requires real process data rather than pipe size alone.<\/p>\n<\/header>\n
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What Does \u201cVentil Papierstoffmengenregelung\u201d Mean?<\/h2>\n

The German expression can be translated as paper stock quantity control valve<\/strong> or paper stock flow control valve<\/strong>. It usually refers to a modulating valve that adjusts the amount of pulp suspension delivered to a paper-making process.<\/p>\n

In basis-weight control, the valve can receive a signal from the quality-control or flow-control system and make small position changes. Increasing or reducing stock flow affects the fiber mass sent toward the headbox and forming section. Stable response supports consistent grammage, machine operation and product quality.<\/p>\n<\/section>\n

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Where Is a Paper Stock Flow Control Valve Installed?<\/h2>\n

The exact position depends on the mill layout. Typical duties include stock-preparation flow control, machine-chest discharge, mixing and dilution systems, approach flow before the headbox and basis-weight control loops. Related valves also regulate white water, dilution water, chemicals, steam and wastewater.<\/p>\n

The process engineer should distinguish between the main fibrous stock line and clean utility lines. A valve suitable for dilution water or steam may not be suitable for pulp stock containing long fibers, recycled material or abrasive fillers.<\/p>\n<\/section>\n

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Which Valve Types Can Control Paper Stock Flow?<\/h2>\n
\n\n\n\n\n\n\n\n\n\n
Valve type<\/th>\nPossible use<\/th>\nMain advantage<\/th>\nReview carefully<\/th>\n<\/tr>\n<\/thead>\n
Segmented ball or ball-sector valve<\/td>\nModulating stock and basis-weight control<\/td>\nOpen flow path, useful rangeability and rotary actuation<\/td>\nSegment geometry, seat design, actuator accuracy and wear<\/td>\n<\/tr>\n
V-port ball valve<\/td>\nControlled flow of low- or medium-consistency stock<\/td>\nDefined opening characteristic and compact construction<\/td>\nFiber accumulation, required torque and seat compatibility<\/td>\n<\/tr>\n
Butterfly control valve<\/td>\nLarge-diameter, lower-consistency or water duties<\/td>\nCompact face-to-face dimension and low weight<\/td>\nControl range, disc interference, velocity and shutoff<\/td>\n<\/tr>\n
Knife gate valve<\/td>\nStock-line isolation<\/td>\nGate can cut through fibrous media during closure<\/td>\nGenerally selected for isolation rather than precise modulation<\/td>\n<\/tr>\n
Globe or sliding-gate control valve<\/td>\nSteam, water and selected process-control duties<\/td>\nPredictable control characteristic in suitable clean service<\/td>\nNarrow passages and fiber-plugging risk in stock service<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

No valve type is correct for every paper mill. The stock consistency, fiber length, freeness, fillers, contaminants and required control accuracy should determine the final design.<\/p>\n<\/section>\n

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How Does Pulp Consistency Affect Valve Sizing?<\/h2>\n

Pulp consistency is the percentage of dry fiber in the stock suspension. As consistency increases, pulp behavior can depart from clean-water sizing assumptions. Fiber networks influence pressure loss and effective valve capacity, particularly at low differential pressure.<\/p>\n

Published flow-control guidance indicates that stock below roughly 2% consistency can behave closer to water for sizing purposes, while higher consistency may require a pulp-stock correction factor. The correct factor depends on consistency, differential pressure and valve design. The supplier should size the valve from the actual operating points rather than applying a universal correction.<\/p>\n

An oversized control valve may operate close to its seat, where small position changes cause unstable flow and fibers can collect. An undersized valve can consume excessive pressure, increase velocity and limit production. Proper sizing should cover minimum, normal and maximum conditions.<\/p>\n<\/section>\n

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8 Selection Checks for a Paper Stock Flow Control Valve<\/h2>\n
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  1. Stock consistency:<\/strong> Provide minimum, normal and maximum consistency rather than a single design value.<\/li>\n
  2. Fiber properties:<\/strong> Identify fiber source, length, freeness, recycled content and tendency to form bundles.<\/li>\n
  3. Solids and additives:<\/strong> State filler content, coating particles, sand, scale and other abrasive or clogging materials.<\/li>\n
  4. Flow conditions:<\/strong> Provide minimum, normal and maximum flow together with upstream and downstream pressure.<\/li>\n
  5. Control objective:<\/strong> Define whether the valve controls flow, consistency, blending ratio or paper basis weight.<\/li>\n
  6. Valve characteristic:<\/strong> Confirm the required relationship between travel and flow, including the usable control range.<\/li>\n
  7. Actuator performance:<\/strong> Specify pneumatic or electric actuation, positioner signal, resolution, deadband, fail position and operating speed.<\/li>\n
  8. Maintenance needs:<\/strong> Review cleaning access, replaceable wear parts, packing adjustment and the space available for removal.<\/li>\n<\/ol>\n<\/section>\n
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    Why Are Actuator Accuracy and Mechanical Backlash Important?<\/h2>\n

    A basis-weight control loop may command many small valve movements. Lost motion in the linkage, gearbox or actuator can prevent the closure member from reaching the requested position. The controller may then continue correcting, which can produce cycling and sheet-weight variation.<\/p>\n

    The complete assembly should therefore be evaluated as one control unit. Check actuator sizing at the maximum differential pressure, positioner resolution, shaft and coupling stiffness, bearing condition and actual valve-position feedback. Fast movement alone does not guarantee stable control; repeatable positioning is more useful.<\/p>\n<\/section>\n

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    Material and Trim Selection<\/h2>\n

    Paper stock can cause abrasion, corrosion and fiber buildup. Body, closure member, shaft, seat and hardfacing materials should match the stock chemistry and solids content. Stainless steel or higher-alloy wetted components may be considered where corrosion is a concern, while hard coatings or wear-resistant trims may be needed for abrasive fillers.<\/p>\n

    Elastomer and packing selection should account for process chemicals, temperature, cleaning agents and washdown conditions. For bleaching chemicals, black liquor or white liquor, complete chemical compatibility requires a separate review because those services can be more corrosive than ordinary paper stock.<\/p>\n<\/section>\n

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    Information Required for Valve Sizing and RFQ<\/h2>\n
    \n\n\n\n\n\n\n\n\n\n\n\n
    RFQ item<\/th>\nInformation to provide<\/th>\n<\/tr>\n<\/thead>\n
    Medium<\/td>\nStock type, consistency, fiber length, freeness, fillers and chemicals<\/td>\n<\/tr>\n
    Operating data<\/td>\nMinimum, normal and maximum flow, pressure and temperature<\/td>\n<\/tr>\n
    Pipeline<\/td>\nNominal size, schedule, end connection and installation orientation<\/td>\n<\/tr>\n
    Control duty<\/td>\nRequired Cv or Kv, control range, characteristic and allowable pressure loss<\/td>\n<\/tr>\n
    Actuation<\/td>\nPower source, control signal, fail position, feedback and operating time<\/td>\n<\/tr>\n
    \u0e27\u0e31\u0e2a\u0e14\u0e38<\/td>\nBody, trim, seat, packing, coating and corrosion requirements<\/td>\n<\/tr>\n
    Documentation<\/td>\nApplicable standards, testing, certificates, drawings and inspection requirements<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n
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    Common Specification Mistakes<\/h2>\n