By Josh Cosford, Contributing Editor The three most common ways to control hydraulic actuators are with lever valves, cartridge valves or sandwich valves. Lever valves are available as monoblock or stacked valves, and are primarily for directional control. Cartridge valves have nearly infinite possible combinations, but must be used with bodies or custom manifolds. Sandwich […]
Engineering Basics
What does pressure really mean?
Pressure is simply the force applied perpendicular to the surface of an object per unit area over which that force is distributed. However, there are many ways to reference and identify pressure, which is largely dependent upon the application. In many applications, there is a common misconception that all pressure measurement needs to be absolute. […]
How do you calculate HPU pressure and flow requirements?
By Josh Cosford, Contributing Editor Before you select a pump for your HPU, you must calculate your pressure and flow requirements. To calculate flow required by your hydraulic pump, you must know the size and velocity of the actuators it will power. It is important to calculate the maximum flow required during simultaneous actuator operation, […]
What components make up hydraulic power units or HPUs?
By Josh Cosford, Contributing Editor Nearly every single hydraulic system shares one thing in common — they’re run by a hydraulic power unit. Although some units are multitaskers, like the engine on a tractor, most often they’re purpose-built for the single task of converting mechanical energy into hydraulic energy. The scope of a power unit […]
How do accumulators improve system performance?
Hydraulic accumulators are pressure vessels that store and discharge energy in the form of pressurized fluid. In essence, potential energy is stored in a compressed gas and released on demand to force oil from the accumulator and into the circuit. Here are some important benefits accumulators provide, and how they make hydraulic systems better. Energy […]
What is a linear position sensor?
Several technologies exist to provide position feedback or data of a cylinder’s position. Linear position sensors convert the position into a proportional analog or digital signal. LVITs—Linear Variable Inductive Transducers—are contactless position sensing devices, with sensing ranges up to 30 inches or more. Most designs feature an inductive probe surrounded by a conductive tube. This is […]
How does a hydraulic accumulator work?
Hydraulic accumulators are energy storage devices. Analogous to rechargeable batteries in electrical systems, they store and discharge energy in the form of pressurized fluid and are often used to improve hydraulic-system efficiency. An accumulator itself is a pressure vessel that holds hydraulic fluid and a compressible gas, typically nitrogen. The housing or shell is made […]
The ins and outs of piggy-back hydraulic cylinders
Piggy-back cylinders, as the name implies, are two opposing hydraulic cylinders mounted with the bodies on top of each other. Taking advantage of this configuration enables a longer stroke from a relatively short overall length. They’re somewhat similar to familiar telescoping cylinders, where several cylinder stages are built inside of one another, and the unit […]
Load-holding valves made simple
Load-holding valves, or counterbalance valves, are simple devices but critical to mobile machine stability and cost. Contributed by Todd McIntryre, Global Planning and Strategy Manager, SiCV, Eaton Load-holding valves, which are also known as counterbalance valves, are a small but important part of any mobile machine. Though they are simple in design, their application can often […]
How much hydraulic safety awareness do you have?
Hydraulic safety knowledge and respect for the hazards of hydraulics is gained through training and mentoring; however, the practice of learn as you go is an unacceptable way to gain safety knowledge. Even though electrical components meet standards, when they are assembled into a circuit, the circuit must be inspected to meet codes of the […]
