The origin of the DynaFlo pattern grew out of our analysis of competitive patterns in the Durametal 2-zone arena. We found that the 2-zone design provided an increase in open area at the I.D. of the plate. This coarse inner area was often achieved by cutting every other bar out of the pattern, but was sometimes just a coarser version of the outer section. The outer area of the plate was a standard parallel bar. One thing we noticed about some designs on the market was the development of a pumping or feed groove between the fields of bars. This type of design is used on the small high angle conical fillings.
The features that identify a DynaFlo pattern form from other patterns are:
- Radial feed grooves between bar fields and plate edges. These grooves provide a linear path for the stock to feed into the plate.
- Low angle chamfers in feed grooves that help fibers get to the top bar edge.
- Variable angle chamfers at O.D. to reduce the “Lipping” effect caused by uneven plate wear.
- Elimination of the “Break Bar” section. This provides for more bar edge length, smoother low-to-plate inlet, low angle chamfers to provide good feeding and fiber floc reduction.
- Subsurface dams in radial feed grooves to prevent stock channeling and promote bar surface loading.
- Curved I.D. bars. The unique curved bar inlet is a J&L exclusive design that provides a smooth transition from the wide open feeding section into the refining section.
- Deep I.D. grooves that increase the open area in the most critical section of the plate—the I.D.
- Curved Bars
- Variable Angle Chamfers
- Radial Feed Grooves
- Single or Multizone
- Strategically Placed Dams
- Optimizes Pulp Flow
- Extends Plate Life
- Improves Feeding Capacity and Fiber Quality
The DynaFlo curved bar design promotes continuous transition between zones, thereby enhancing the smooth, uninterrupted flow of fiber from the plate’s ID to the OD. DynaFlo’s unique design also improves feeding capacity—meaning it can deliver equal fiber quality [intensity] at higher capacity, or maintain comparable throughput capability at lower intensity.
The J&L DynaFlo curved bar refiner filling features a variable bar and groove design with deeper and wider grooves towards the plate’s ID and a smooth, gradual transition to narrower bars and grooves at the OD of the plate.
DynaFlo’s flow smooth transition zones also incorporate a balanced open area from the plate’s inlet to outlet. This combines with the deeper grooves in the plate’s ID to deliver improved flow characteristics and means the fiber mat isn’t disrupted as it transitions from the feeding zone to the refining zone. Less restrictive flow contributes to improved fiber quality [reduced intensity at higher capacity] as well as extended plate life and significantly reduced downtime.
DynaFlo can be engineered to deliver enhanced performance in virtually any low consistency refining application so contact us today to find out how it can help your company boost process efficiency.
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Refiner Plate Design
Different refiner applications require different plate designs as system optimization is undertaken.
Fiber treatment, hydraulic capacity and breakage resistance are three critical parameters that must be considered when designing and applying low consistency refiner plate patterns.
A paper mill can optimize its low consistency refining operations on two fronts:
- Monitoring and eliminating as many detrimental hydraulic, mechanical and process conditions as possible.
- Ensuring that the proper plate designs and alloys have been selected.
By working together with our papermakers, J&L Fiber Services seeks to develop strategies to optimize the unique needs and performance of a particular paper mill.
Given the difficulties of being able to control all of the many process variables, refiner plate design becomes extremely critical. The key design parameters, relative to delta P (refiner pressure control) are: groove depth, groove profile, number of bars & total pumping angle.
The intensity of refining that is required will determine the bar width/groove relationship,or pitch. However, groove width should be altered to optimize the throughput rate. This can be done without changing the pitch or intensity by altering the bar width correspondingly.
A special caution when altering groove depth for flow control: While no appreciable negative effect will occur when groove depth is reduced for lower flow rates, increasing groove depth poses some risks. First, it is less efficient than increasing groove width. Second, it can have a negative effect on energy efficiency, because increasing groove depth increases the no-load energy required to spin the rotating element in the stock slurry.
Bar angle is significant to the extent that it affects the delta P and is a tool for hydraulically balancing the refiner.
The relatively infrequently used practice of running the low consistency refiner plates in the holdback position can effectively compensate for low flow conditions which are detrimental to fiber quality, plate life, etc. During holdback, the intersecting bar angle between the rotor and the stator is moving towards the center line of the refiner rather than towards the periphery of the disc, as in pumping position. Holdback will increase the turbulence in the grooves and the plate gap.