By Josh Cosford, Contributing Editor The line that separates the performance of servo and proportional valves has blurred in recent years. Some may consider a servovalve to be any valve capable of accurately positioning your actuator with closed-loop control. However, in everyday hydraulic circles, many industry professionals describe a servovalve as a valve with a […]
Engineering Basics
What is the best raw material for hydraulic cylinder repair?
By Josh Cosford, Contributing Editor When your customer’s cylinder arrives on your dock for repair, how often do you consider raw material when you quote the overhaul? Probably very little. Most hydraulic cylinders are manufactured from a combination of 1018/1020 cold rolled steel for the “square” components such as flanges, heads and caps. Piston rods […]
How to specify pressure sensors for hydraulic applications
Learn about common challenges and key specifications to consider when selecting pressure sensors for hydraulic systems with pressures greater than 50 bar (725 psi). Contributed by By Daniel Mullen, Product Manager, Sensata Technologies Pressure sensors are critical components in fluid power systems, where they are used in a control loop with a Program Logic Controller […]
When should you use rotary actuators?
Rotary actuators, in many cases, are a hybrid of linear and rotary actuators. Of course, in the fluid power realm, linear and rotary actuators are more affectionately referred to simply as cylinders and motors, respectively. A cylinder creates linear force when pressure acts up its piston’s surface area, while a motor creates rotational force when […]
How does hydraulic cylinder repair work?
By Josh Cosford, Contributing Editor When well cared for, hydraulic cylinders should last decades. So long as they were designed for their application — meaning they perform within the bounds of their environment — there should be no reason for damage or wear outside of regular use. The mount, rod and raw material should have […]
What are the most common hydraulic cylinder piston rod problems?
By Josh Cosford, Contributing Editor It would help if you never underestimate the importance of your cylinder rod. The rod is not just the object transmitting the force from the cylinder’s piston but also the interface between that cylinder and your machine. Before you can correctly select and then design the piston rod, you must […]
How do you safely precharge an accumulator?
By Josh Cosford, Contributing Editor When high-pressure hydraulics fail, the result is often a whimper as a seal blows out and pressure decays to useless levels. The harm to the surrounding environment and spectators is often little or none, which is why high-pressure hydraulic systems are so popular. However, when high-pressure pneumatic systems fail, you […]
What are flow control valves?
In the collection of hydraulic valve components, flow control valves are any device manufactured for the purpose of modifying the rate of fluid flow in a portion of a hydraulic circuit. Flow variability occurs through the adjustment of the effective orifice size inside the valve, and this is achieved through various techniques based upon the […]
How do relief valves work?
By Josh Cosford, Contributing Editor It seems like a question with an easy answer, but you’d be surprised how often people ask, “how do relief valves work?” We in the fluid power industry take our knowledge for granted, but each and every one of us was at some point ignorant of literally every hydraulic component […]
What is the difference between fixed and variable pumps?
For novices in the fluid power industry, lack of understanding between the fixed flow and variable flow pumping concepts is quite common. A hydraulic pump has one mission, and that is to transform incoming mechanical energy at its shaft into hydraulic energy capable of transferring force to actuators somewhere downstream. This transfer of force is […]
