WorldWide Drilling Resource

65 WorldWide Drilling Resource ® MAY 2013 Hydraulic Training by J. Eric Freimuth Hydraulic Training Associates Cylinder Force & Speed Calculation Over the years, I have trained many people how to troubleshoot systems. This article is a bit of a change because I want to help determine how to select the proper cylinder for the job. Many times I have been called out to ascertain why the cylinder failed, or why the sys- tem is not functioning according to what the design called for. I want to take the next few articles to supply you with a few pages from my class material to help with these decisions. During the course, we look at the various types of cylinders available as well as the various types of seals in the industry. How do we determine the size, force, or speed for a particular applica- tion? Next, we will discuss how to deter- mine these calculations. What bore size is needed to move 25 tons? What cylinder bore diameter and at what pressure should I use? The solution is as follows: Calculate the required force of 25 ton x 2000, (since there are 2000 pounds in a ton). This will give a force of 50,000 pounds. Looking at the chart, you see there are several combinations of cylinder diam- eters and pressures which will produce 50,000 pounds of force or more. For example, a 6-inch piston will produce 56,550 pounds at 2000 psi, or a 7-inch piston at 1500 psi will produce 57,725 pounds. An 8-inch piston at 1000 psi will produce 50,265 pounds and a 10-inch piston at 750 psi will lift 58,900 pounds. There are many combinations which can be used; the final choice is a matter of preference or matching the pressure and flow capability of other components, particularly the pump. In practice, choose a combination which will produce 10-25% more than is actually required by the load alone. This will give you a safety allowance to take care of pressure losses in valves and piping, as well as mechanical loss- es in the cylinder. Our next article will discuss how force plays a role in sizing a cylinder. Eric Eric Freimuth may be contacted via e-mail at admin@ worldwidedrillingresource.com