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Precise Basis Weight Control for Consistent Paper Quality
Maintaining accurate basis weight is essential for stable paper machine operation. Ramén KS Ball Sector Valve provides fast, accurate consistency control before the headbox, helping paper producers achieve consistent sheet weight, improved product quality, and stable downstream operation.
Background
Basis weight control is a critical part in a paper machine operation. The basis weight valve, installed in the stock preparation department in front of the paper machine, controls the consistency of the pulp entering the headbox, dictating the paper weight and quality at the end of the process. The valve is controlled by a control signal showing the difference between the measured basis weight of the sheet on the reel at the end of the paper machine and the set-point. Too high measured basis weight makes the valve close to lower the consistency in the system while too low basis weight causes the valve to open to higher the consistency before the head box. Improper control adversely affect downstream process sections such as drying and calendar sections resulting in even more deviation from the requirements. Hence, a quick and highly accurate control solution is essential to meet customers’ specifications.
A Complete Valve Solution for Basis Weight Control
Ramén Valves offers the Ramén KS Ball Sector Valve model KS-1A, a robust ball sector valve specifically designed for basis weight control applications. The valve features a unique ball-to-shaft connection that eliminates backlash, ensuring highly accurate and repeatable control. Manufactured in stainless steel AISI 316L, the KS-1A is a soft-seated control valve with a carbon/graphite-reinforced PTFE seat ring and a ball sector coated with SuperExpanite® for long-term durability.
The high resolution controllability is further enhanced by Oden backlash free actuator with stepper motor controlled by a microprocessor. This solution is suitable for both recycled and bleached pulp with consistencies ranging from 2% to 12%, meeting the requirements of a wide variety of pulp and paper processes. To ensure optimal performance, each valve is accurately sized for the application based on the based on the customer’s process data.
Process Data Required for Valve Sizing
To ensure optimal valve sizing and control performance, the following process data should be provided with your inquiry.
• Flowrate: Min/Norm/Max
• Pressure upstream the valve
• Allowable pressure drop
• Temperature
• Type of fibre
• Pulp concentration
• Pipe size
• PH level
Ramén KS Ball Sector Valve model KS-1A features & specifications
The valve features and benefits
• Extremely compact, low weight and robust design
• High control rangeability (300:1)
• Enhanced control accuracy with minimum backlash
• Equal percentage characteristic
• Low torque operation
• Self-drained with no hidden cavities and no clogging
• Low maintenance and long lifetime
Valve technical specifications
• Size range: DN 50 – DN 300
• Pressure Class: PN 16 – 40
• Temperature range: -40°C to +170°C
• Capacity: Kvs: 94 -3840 [m3
/h] Cv: 110-4500 [gpm]
• Material: Stainless steel EN 1.4409, AISI 316L
• Seat ring: PTFE for low torque and tight shut off
Actuator features:
• Compact design and backlash free control
• Control precision of 5.000 steps in 90° valve travel
• Adjustable running time and acceleration
• Hand wheel or key for manual operation
• Built-in feedback positioning on the main shaft
• Positioning with high resolution
• Duty cycle 100%
• No need for additional control box or cabinet
• Programmable with free Oden Valve Program
Actuator technical specifications:
• Power supply: 24/48 VDC
• Control signal: 4-20 mA or 0-10V
Galvanically isolated control and feedback signals,
Modbus 485, digital 24 VDC 3-point control.
• Running time: ~ 3 Sec. to 15 Min.
• Enclosure protection class: IP67
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