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The Kadant Blog

How the LJX™ Rotary Joint and Rigid Syphon System Improves Corrugator Runnability

The LJX rotary joint and rigid syphon system is designed for critical preheater and preconditioner rolls used in corrugated packaging manufacturing. It enables efficient and even heating of both medium and linerboard. To heat the liner or medium, steam enters the roll, condenses, and releases its latent heat energy. Differential pressure pushes the resulting condensate and some blow-through (i.e., non-condensed) steam into the rigid syphon and back through the rotary joint.

LJX Rotary Joint and Steam Heated RollJoint and Roll SM
Steam and Condensate Flow
Cutaway SM

The LJX rigid syphon is precisely positioned to maintain a layer of condensate that continuously cascades, creating turbulent movement and efficient heat transfer. If the syphon is too close to the roll’s wall, the condensate layer becomes too thin and will begin to rim, forming an insulative layer.

Cascading CondensateCascading SMRimming CondensateRimming SM

To maintain syphon positioning, LJX rotary joints are mounted with heavy-duty mounting rods and integral sleeves. They hold the rotary joint and syphon in position over time. Internally, the syphon assembly includes a one-piece, thick-wall mechanical tube, and an integral tapered wedge to provide rigidity. The SecureLock™ retention plate secures the syphon in place.

External FeaturesExternal Components SMInternal FeaturesInternal Components SM

The LJX rotary joint and rigid syphon system provides a more robust solution than bent syphon pipe systems. The LJX syphon’s 3x shorter length and the self-locking elbow increases stiffness compared to conventional bent pipes. Bent syphon pipes bounce erratically inside the roll and result in inefficient, uneven heat transfer and eventual metal fatigue failure.

LJX Rigid Syphon System versus Bent Pipe SystemBent Syphon SM

The LJX rotary joint and rigid syphon system is used by corrugated packaging manufacturers that require increased reliability and runnability with a secure and simple mounting method. Watch this video to learn more about the LJX rotary joint and rigid syphon system.

  • Written by:
    Casey Beck

    Casey Beck

    Director of Marketing, Kadant Johnson

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