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Pneumatic GCL & GCD Series

Performance | Dimensional Data | Selection Guide

High Frequency GCL & GCD

Dual roller vibrators use compressed air to push two concentric rollers around a shaft producing rotary vibration. Because of the size and weight of the rollers, these vibrators produce much more force than ball vibrators.

When harnessed by proper mounting of the dual roller vibrator, this rotary vibration is transferred through the hopper or bin wall to the material within. As the material vibrates it is displaced from the hopper wall reducing friction and allowing gravity to restore material flow. Proper mounting also disperses the rotary vibration over a large area producing uniform material flow. Since rotary vibration is directional, material will be encouraged to flow in the direction of the rotating rollers.


  • High frequency dual roller vibrators operate at relatively high RPM producing high frequency vibration. They also produce large amounts of force. This makes them well suited for compacting or unloading large quantities of fine materials, such as sand or cement, from railcars, batch hoppers, or storage bins. Excellent for use with wet fine material. The high frequency excites the fine particles and the high force moves the large mass.
  • These same properties make them highly useful for consolidating concrete. It takes this unique combination of frequency and force to remove air bubbles, disperse the large aggregates, and ensure the cement fines are evenly distributed to coat the aggregates. Proper use of vibration means less water is needed, which produces stronger concrete. Air bubble removal and even cement-aggregate distribution produces a smoother finish. High frequency dual roller vibrators make pouring concrete quicker and easier without harming the forms. They are commonly found on battery molds, compaction tables, tilt tables, and a large variety of forms and molds for girders, tees, columns, culverts, vaults, containers, septic tanks, concrete pipe, etc.


  • Produces Uniform, Directional Flow.
  • High Frequency and High Amplitude Vibration.
  • Versatile - Easy to control force and frequency by adjusting air supply.
  • More Reliable Start-up - Dual-roller design assures fast, reliable starts every time. Single roller designs are frequently hard to start.
  • No Bearings or Motors - means reliable performance, lower maintenance costs, and simple, easy operation.
  • Fully Portable - GCL model is portable and can easily be moved from form to form. Fits standard mounting brackets. A convenient handle allows easy and safe transport.
  • Rigid Mounting technique - Provides secure mount for maximum safety and performance.
  • Most Rugged & Wear Resistant Available - Only two moving parts are the two hardened steel rollers. The steel shaft is hardened and ground for long life and even wear. Extra short bolts screw directly into the housing instead of long through bolts that break more easily. A single piece shaft with a hose barb on one end lasts longer than conventional two-piece shafts that can fret or rust. Inside cover surfaces are chrome plated for longer life.
  • Easy repair and maintenance - Global offers replacement parts and an extensive rebuild program that refurbish the vibrators to like-new condition. This can significantly reduce the cost of ownership by extending equipment life.
  • Five Year Warranty.


Two body styles - The GCD has permanent 4-bolt mount. The GCL is for portable use. It has a convenient handle for carrying and fits universal mounting brackets.

Operating Requirements:

  • Filtered & Lubricated Air.
  • 40-80 PSI depending on model. 46-67 CFM.
  • Maximum Ambient Temperature = 200F (93C).

Vibrator Selection:

  • Selection based on the weight of the material in the sloped portion of the container.
  • Select the high frequency vibrator capable of producing a force equal to one-tenth the weight of the material when the vibrator is operating at medium pressure (40-60 PSI / 2.8-4.1 BAR).
  • For concrete consolidation, the selection depends on the consistency of the concrete.
< 15,000 < 6,800 GCD,GCL-4400
15,000-25,000 6,800-11,300 GCD,GCL-5000
25,000-40,000 11,300-18,100 GCD, GCL-5500
40,000-60,000 18,100-27,200 GCD, GCL-6500
60,000-75,000 27,200-34,000 2 X GCD, GCL-5500
> 75,000 > 34,000 2 X GCD, GCL-6500
VERY STIFF CONCRETE < 0.5" Vibrator force output should be equal to 200-300% of the total concrete and form weight.
STIFF OR STIFF PLASTIC CONCRETE 0.5 - 2.0" Vibrator force output should be equal to 130-150% of the total concrete and form weight.
PLASTIC OR FLOWING CONCRETE > 2.0" Vibrator force output should be equal to the weight of the concrete and form.


  • Manual Valves - 2-way manual ball valve used to turn the vibrator on and off for normal operation.
  • Solenoids - For remote or automated control, use 2-way normally closed solenoid valve to turn the vibrator on and off for normal operation.
  • Airline Kits - Required for trouble-free operation and long life of high frequency dual roller vibrators. Includes airline filter, lubricator, and pressure regulator with gauge.
  • Universal GCL Bracket - Heavy-duty bracket used to mount portable GCL models on hopper or forms. Has special swivel nut that lasts longer and helps hold the vibrator tighter than regular nut and flat washer.
  • Special Brackets - Provides wedge mount for railcar pockets for GCL models.
  • Sirometer - Convenient, compact RPM Meter for measuring vibrator speed.

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