The power of hydraulics leaves no doubt: If you work around hydraulics, you better know what you’re doing because a mistake can cause serious injury or worse. Not so obvious it the threat of injury from hydraulic leaks.
Hydraulic leaks are often described as being analogous to electrical leaks. If electrical leaks occur in a cable, the sparks produced usually cause operators to shut down the machine immediately and investigate the situation. Hydraulic leaks, however, are often considered a nuisance, so a machine continues to run until someone gets around to fixing the leak.
The problem is, hydraulic leaks can also inflict serious injuries. An invisible pinhole leak in a hydraulic hose under pressure can release toxic fluid at more than 200 m/sec — close to the muzzle velocity of a gun. A jet like this can act like a hypodermic needle, penetrating both protective clothing and skin. Other dangers from hydraulic bursts or pinhole leaks can include personal injury from fluid burns and injection, fires, explosions, electric shock and mechanical failure.
Gates Corp., Denver, offers LifeGuard 4000-sleeving for hydraulic hose. LifeGuard 4000 can hold back 8,000 psi (55 MPa) bursts and 4,000 psi (27.5 MPa) pinhole leaks at 100°C for up to five minutes on ¼- to 1-in. hose sizes. The sleeve is slipped onto the hose and clamped and secured at each end with special clamps. The clamps allow leaking fluid to escape, so it won’t collect behind the sleeve and cause it to burst. Fluid leaking past the clamps lets the operator know that there is a leak in the hose.
The inside sleeve layer is made of a tightly woven filament nylon fiber that stretches up to 20%. By stretching, it can absorb the energy of a burst or pinhole leak. The outer sleeve is a textured nylon material that further helps to contain escaped fluids and redirects them to the clamped ends of the hose for release.
In the past, protective sleeves were installed on hose primarily to protect them from abrasive wear, extreme localized heat (from manifolds, for example), and other conditions that could damage or cause premature wear to a hose’s outer cover. So the LifeGuard 4000 takes this concept a step further by protecting the hose from ambient conditions and protecting operators from any potential danger of high-pressure leaks. This is especially important with today’s higher pressure systems and more compact machine designs.
LifeGuard line-of-sight sleeving is a safe, effective and economical alternative to metal and plastic shielding. The sleeving is compatible with a wide range of fluids, including environmentally friendly liquids and biodiesel fuel, so it can be used in all kinds of situations. It protects at temperatures up to 100°C, the SAE standard for most industrial hydraulic applications.