High pressure defines hydraulics, and the linear actuator we call the cylinder is the pièce de résistance of our industry. Other methods of creating rotational force may closely mirror the performance of a hydraulic motor. Still, a hydraulic cylinder has no peer for linear force (I’m looking at you, electric linear actuator). The force advantage…
Hydraulic cylinder repair: Metric in an Imperial world
By Josh Cosford, Contributing Editor We live in a global village where local preferences seem to matter less, and acceptance of unfamiliar ideas more widespread than ever. Thirty years ago, the idea of metric bolts, nuts, threads or other objects measured in round numbers was cringe-worthy, especially in the manufacturing space. Many found it annoying […]
What should you know when specifying quick couplings?
By Josh Cosford, Contributing Editor Hydraulic quick couplings provide users with the ability to rapidly connect and disconnect hydraulic hoses to machines or other sections of plumbing. Also called quick-connects or quick disconnects, these fittings allow fluid to flow when the male and female sides are locked together. Conversely, when disconnected, the quick couplings prevent […]
What is the best raw material for hydraulic cylinder repair?
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 mostly likely adhere to 1045 […]
What is the difference between cellulose and glass filter media?
By Josh Cosford, Contributing Editor Manufacturers make cellulose fibers from long chains of plant material processed into a pulp and then drawn out into strands. Glass media comes from a more complicated process of first drawing molten silica fibers and then combining them into a strand using a resin binder. The product of either process […]
Taking a deep dive into the hydraulic reservoir
Hydraulic reservoir design is critical in power unit performance, so selecting the right style elements will ensure efficient circuit design. If you have a hydraulic system, you have a reservoir. Full stop. Even “reservoir-less” systems still require an expansion tank to hold excess fluid. Aside from such unconventional designs, hydraulic reservoirs offer benefits above and…
Symbology 401 – logic elements
Logic elements are fantastic little creatures. Sometimes call DIN valves or slip-in cartridge valves, they are the most basic valve design capable of controlling direction, flow and pressure. Their simple poppet construction nearly guarantees reliability while flowing upwards of a thousand gallons per minute or more. Unlike most of the Symbology series, this one requires…
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 is telematics used on mobile machinery?
In many ways, Industry 4.0 has yet to achieve widespread proliferation throughout fluid power machinery as it seemed we were promised. Baby Boomers are still waiting for their flying cars as promised by the Jetsons. It’s been nearly sixty years since the Jetsons got our hopes up, so I hope it doesn’t take so many […]
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 benefits of urethane seals?
Urethane (or polyurethane) seals are among the most versatile and durable materials used in fluid power sealing. Urethanes are cast into billets or molds to create the seals used in many of the hydraulic components you see every day, such as pump shaft seals, cylinder pistons and rod seals. The material benefits from countless possible […]
When should you use thermoplastic hoses?
By Josh Cosford, Contributing Editor Thermoplastics are polymers with a unique capacity to become soft, pliable and moldable when heated while solidifying upon cooling. The moldability range lies between its glass transition temperature* and its melting point, so it’s essential to avoid overheating the material. Popular techniques such as injection molding and extrusion produce many […]
Hydraulics keep their cool through heat exchanger technologies
Heat exchangers help remove heat from hydraulic power units, helping to maintain fluid viscosity and reduce wasted energy. For all its myriad benefits, hydraulics still has a fundamental downside — heat. Adhering to the Laws of Thermodynamics, we must accept that any energy conversion results in increased entropy. In other words, converting mechanical energy from…
Troubleshooting common hydraulic vane pump problems
Vane pumps are quiet, efficient and reliable, especially when they’re provided care. However, they’re not indestructible and experience problems like every other pump. Just like all hydraulic pumps, when taken care of, they may last you a lifetime. Part of improving your vane pump’s life span is understanding what can go wrong through intelligent troubleshooting.…
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 […]
What causes O-ring failures?
By Josh Cosford, Contributing Editor An O-ring is a polymer seal most often used in fluid power as either a dynamic or static seal. For light-duty pneumatic applications, an O-ring is a suitable seal technology used in pistons, piston rods, valve spools and other locations in air systems. O-rings best suit the sealing of static […]
How does water impact hydraulic fluid?
Most hydraulic fluid is oil-based, so we cannot forget the adage that oil and water do not mix well. However, when it comes to the hydraulic oil transferring energy around your hydraulic system, much more is at stake. Whether free or in saturation, the potential harm from water is more detrimental than merely pooling at […]
What is skiving, and when should you use it on your hose assemblies?
Skiving is removing the outer cover at the end of a hydraulic hose in the location of the crimp fitting. For some high-pressure applications, the hose’s inner tube ID may be skived to allow the hosetail to better fit. Using a specialized machine with externally rotating mandrels, the tooling cuts and then peels the outer […]
Laws are infallible
By Josh Cosford, Contributing Editor Physical laws, unlike governmental laws, are perfect. The heavy hand of the (physical) law keeps our fluid power realm in check, dictating liquids and gases’ behaviours at every location. I’d like to say very few alternate engineering fields so heavily rely on these laws and principles as fluid power, but […]
You can’t get something for nothing
I once had a customer call to request I visit them at their own customer’s site to help with a “breakdown.” I’m always down to help a customer, so I gladly paid a visit. Arriving on-site, many looming pieces of machinery greeted me in a heavy equipment yard. An excavator sat atop a float trailer […]
Hydraulic symbology 305 – condition monitoring symbols
Condition monitoring symbols are the lesser-known and lesser-used of the hydraulic library. It’s not that the components or the symbols representing them do not serve a useful purpose. It’s that the order of operations for designing and drawing a hydraulic system are actuators, pump(s), control valves and then conditioning components. Monitoring symbols represent the nice…
Hydraulics in mining: safe and reliable
Eliminating downtime and ensuring safety in mining — two benefits hydraulics provides consistently. By Josh Cosford, Contributing Editor More than almost any other industry appropriating fluid power, mining is where safety sits front and center from design to execution. Surface mining enjoys bragging rights to some of the most massive machines ever manufactured by humans. […]
Hydraulic Symbology 304 – conditioning and monitoring
The use of hydraulic symbols must be comprehensive in your efforts to detail the workings of a complete hydraulic system. Hydraulic machines consist of more than pumps, valves and actuators, of course, even though they are often the stars of the show. Those stars would quickly fall into the other side of fame without components […]
Hydraulics keeps things moving in material handling applications
Hydraulics goes a long way to improve the function, power, controllability and safety of material handling equipment. By Josh Cosford, Contributing Editor Material handling involves the moving, transporting, lifting, and dumping of products, components or bulk ingredients, and mostly within the production and distribution of finished goods. Much of the equipment used for material handling […]
Hydraulic Symbology 303 – Compound Symbols
I’ve explained other compound symbols in previous Symbology lessons, although not from the specific perspective of intentionally using two or more combined symbols to make one complete, functional component. The detailed version of the pressure compensated pump symbol combines tiny cylinders with 3-way, 2-position regulators and a smattering of other small symbols to make one…