November 2016

Cam Roller Constants in Action

Rilco Manufacturing recently supplied a variety of high load bearing Rilco Cam Roller (RCR) constants to a local propane dehydrogenation plant. Several of our B-type constants were selected to compensate for the vertical movement of the piping system at a performance level previously unattainable using a standard or vertical type constant.

The operation of these RCR constants is based on the interaction of force between the main spring load and the forces provided by two interconnected springs. The opposing springs acting in conjunction with the main spring enables achievement of absolute load setting reliability.

Cam Roller Constants Installed in the Field
Overall View of Multiple Cam Roller Constants in a Local Plant

Loads subjected to the main spring, which is connected through the load column, activates the opposing springs, thus activating a system of specially engineered cams, rollers and pins which in turn also exert force on the main spring. As loads are transported over the travel range of the piping, the forces on the main spring and opposing springs change based upon the angle created by the specific shape of the cams, and the design characteristics of the spring.

As loading is applied and the travel moves downward towards the apex of the cams, the opposing spring load is minimized in direct proportion to loading on the main spring. Upon reaching the apex, the opposing force is zero, as the main spring is carrying the load without assistance, traversing past the apex, in a downward motion, the direction of the compensating springs begin to reverse thereby reducing the load on the main spring as well. The constant support is achieved as a result of the alignment of these components so that any deviations in the load are matched exactly with the loading on the main spring.

Cam Roller Constant Assembly in the Field
Rilco Cam Roller Constants Supporting Rilco Fabricated Floating Rings in the Field

Advantages of Rilco Cam Roller Constants Over Lever Type

  • RCR Constants have wider load and travel ranges than lever type 
  • A single central suspension point on the RCR constant with completely linear travel motion imposes no bending moments on supporting steel 
  • More compact overall package dimensions of the RCR as opposed to the large lever type overall size 
  • Lower load deviation on RCR constants than the lever style reduces stress in the piping system 
  • RCR constants have a wide load adjustment range. A typical lever style constant has +/- 10% field adjustability while the RCR has -30% to 100% load adjustability depending on the particular set load 
  • You can observe a direct reading on the linear travel scale of the RCR constants as opposed to the arced scale on the traditional constant for easy determination of pipe movements 

​Do you have any requirements for our RCR constants or any other pipe supports or steel fabrication on your upcoming projects? Please let me know how I can serve your needs.