Scissor Style Top Loading Arm

Primarily used to load and unload tank trucks where the reaches will be less than 120” (3048 mm).This versatile arm is designed specifically for top-loading installations where a variable operating range is required. The secondary arm rotates 360 degrees in the horizontal plane, providing a spotting allowance of up to twice its length.

Note: The scissor-arm configuration is NOT recommended in 6” size or in all carbon steel or stainless steel construction due to the difficulties an operator would have handling the heavy outboard components.


  • Available in 2", 3" and 4" 
  • Available in carbon steel, stainless steel, aluminum 
  • Choice of flanged, threaded or all-welded construction 
  • Adaptable to tight-fill or closed system loading when equipped with additional swivel planes of rotation and/or drop hose; along with required outboard coupling, union or fitting 
  • Truck applications 
  • Smooth, easy operation 
  • Versatility of reach 
  • Limitations :
    • Not recommended for 6” applications
    • Not recommended for all carbon steel or stainless steel construction due to the difficulties an operator would have handling the heavy outboard components 
    • Not recommended for reaches over 120” (3048mm)
    • Not recommended for vapor recovery applications or applications involving heavy attachments (cover plates, cones, steam jacketing, etc.) 
    • A Supported or Unsupported Boom Style Loader would be suggested for any of above applications


Hi-Level Alarm- An effective means to prevent overfilling of tank is always suggested. In many cases both a primary (metering, scale/weight) and secondary (Hi-Level Alarm on Loading Arm) may be in place.

  • For Clear, Light Non-Viscous Materials
    Civacon Optic Cane Probe (Model 1300/1400)    
  • For Dark, Viscous Materials 
    A variety of probe styles, manufacturers can be adapted to fit on your OPW Loading Arm. We have experience with most major overfill brands.

Vapor Recovery- Concern for the environment and your employees is of utmost concern. Several options are available to help retain and recover harmful vapors and avoid excessive splashing, each customized to fit your application. Click here for more information on OPW Vapor Recovery Solutions.

Heating – Loading Arms can be fully or partially jacketed for efficient handling of asphalt, molten sulfur, waxes, resins and other products that are highly viscous or tend to solidify at ambient temperatures. Click here for more information on OPW Heated Loading Solutions.

Loading Arm Insulation – OPW can provide a Custom Insulation Package designed specifically for your loading arm. Unlike field-applied insulation, these packages are completely removable and reusable, making them the ideal solution for loading arm use.

Grounding/Bonding – Suggested for many top/splash loading applications. Available as an option on all Loading Arm designs. 

Electronic Ground Verification

The Civacon model 8030 Ground Verification Monitor is compatible with today’s transport ground systems. The monitor is equipped to provide a permissive signal to allow load rack operation and, if ground is lost, to indicate a non-permissive signal and shut down the loading operation.

Safety Breakaway Coupling

Protects your equipment, piping and personnel in the event of an unintended pull-away. A consideration whenever you are making a tight connection to a truck or railcar.

Quick & Dry Disconnect Couplings – With OPW, you have many options at your disposal for your loading arm termination connections. From the original quick-disconnect Kamlok® coupling to our Epsilon™ dry disconnect coupling, we have a coupling to meet your needs. 

Vacuum Breaker – OPW Engineered Systems Vacuum Breakers permit quick, positive evacuation of the arm after the loading operation is complete. Suggested for any top load/submerged fill application. 

Lockdown- available to help insure that your loading arm stays securely in vehicle during loading operation. Several options available depending on your application. 

Deflectors – Loading arm drop tube can be provided with deflector to help minimize the risk of static build-up and/or product foaming. Can also be used to redirect the upward pressure in order to keep the arm from attempting to rise out of tank during loading. 

  • 463 Deflector (Cone) 
    • Aluminum Construction 
    • 3” & 4”, FNPT 


  • 464 Deflector (Tee) 
    • Aluminum Construction 
    • 3” & 4”, FNPT


Strainers- Loading arm drop tube can be provided with a cast aluminum suction strainer when unloading tank cars. Helps prevent scale and other foreign objects from being sucked into line.

  • 341 Suction Strainer 
    • Cast Aluminum 
    • Galvanized steel screen 
    • 3” & 4” FNPT 

Loading Valves

  • 6400 Series Horizontal Valve – OPW Loading Valves are designed to shut off flow without causing shock in the pipeline. 
    • Adjustable closure rate 
    • 3” & 4” sizes, Aluminum Construction 
    • TTMA Flanged connections 
    • Ball Valves (per application/specification) 

Pneumatic Counterbalancing – An alternative to conventional spring balanced loading arm, pneumatics provide the ultimate in loading arm design.


All OPW Loading Arms can be customized to fit your specific application requirements. We do offer a series of Standard/ optimized solutions that are commonly specified. These optimized selections can be expedited to meet faster delivery requirements.

  • 3” Top Unloading Arm
        All Carbon Steel/PTFE Construction
        Ball Valve
        84” x 24” x 48” Drop
  • 3” Top Unloading Arm
        Ductile Iron/Carbon Steel/Aluminum/Flurocarbon Construction
        Aluminum Load Valve w/ Remote
        84” x 24” x 43” Drop
  • 4” Top Unloading Arm
         Ductile Iron/Carbon Steel/Aluminum/Flurocarbon Construction
         Aluminum Load Valve w/Remote
         84" x 24" x 43" Drop
  • 3” Top Unloading Arm
        Stainless Steel/PTFE Construction
        Ball Valve w/remote
        84” x 24” x 48” Drop
  • 3” Top Unloading Arm
        Stainless Steel/Fluorocarbon Construction
        Tee deflector
        84” x 24” x 48” Drop



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