Product Comparison – SVX vs. Bracket Mounted Cylinder Actuators

As the world advances and grows so does technology. Engineering has allowed us to perform energy intensive duties with greater ease. It is no secret that the Oil and Gas industry is rapidly making the transition from manually operating functions in a hazardous environment to remotely from a climate-controlled room with less hands and labor input.

Bracket Mounted Cylinder Actuators

The first method of remotely operating a ShearFlo® seal directional control valve for BOP hydraulic control systems is by using bracket mounted cylinder actuators, aka AAC/HHC-202/302/402. Simply put, a linear hydraulic or pneumatic cylinder is assembled to a valve via clevis at the “remote handle” and a bracket at the valve housing. The remote handle is different from a manual handle because it has a bushing at the tip that the clevis is assembled to with a rotational degree of freedom. However, because of this rotational movement, vibration and flexure of the tubing must be considered. The footprint of the valve also increases dramatically because the cylinder is offset to the side, so your control system’s plumbing will need to account for the increased length. Despite these downsides, the greatest advantage of using a bracket mounted cylinder actuator is that it is easily retrofittable to the valve. This has been the remote actuation industry standard for over 60 years.

To retrofit an existing valve: (1) get a cylinder with bracket kit; (2) remove the two bolts from the valve (either cylinder 1 or 2 side); (3) align the two front holes of the bracket with the housing holes and reinsert/fasten the bolts; (4) assemble the cylinder to the bracket with provided bolt, spacer, spacer nut, etc.; and lastly (5) assemble the clevis to the remote handle by adjusting the threaded spacing on the clevis/piston shaft. Note that getting the adjustment just right may take a few tries.

This product is also readily available and relatively inexpensive.

SVX Integral Actuators

The latest and superior method of remotely actuating a ShearFlo® seal directional control valve is with the SVX integral actuator. This is a rack and pinion style actuator that is mounted atop the valve that can be remotely (direct or solenoid) piloted with a hydraulic or pneumatic source. More variations are provided to allow customization for your control system such as: 2-position 45° or 90°, 3-position 90°, in direct or spring centered actuation (seven actuation combinations total). For further customization, there are multiple connection points for the power source (air or hydraulic) to operate the cylinders for dual or single acting. This flexibility makes it easier for you to change the actuator logic to fit your constraints and get the job done the way you want.

Because of this integral design it is not as easily retrofittable, requiring a different shaft, detent, and housing from the standard SV models. Nevertheless, it has a smaller footprint in contrast to other actuation methods. The spacing between valve stations is now only limited by the handle and piping to each component. Additionally, the actuator is fixed, so there is no external movement, which maintains low vibration in your control system.

To bring the technological intelligence closer to the SVX and to minimize tubing and labor, solenoid valves can be mounted directly to the actuator. If this is in a hazardous environment, explosion proof solenoid valves can be provided.

Summary

We have covered a lot of ground here that may or may not have helped make the decision towards designing your next remotely actuated hydraulic control system. If you’re more on a budget, have more flexibility with spacing, or perhaps you plan to retrofit manually operated valves, then using bracket mounted actuators may be the best fit for you. However, if you are designing a control system that must maintain a small footprint, requires high performance and must be in line with technological advancements to ensure dependability during remote operations, then the SVX integral actuator should be your choice.