One of our readers wrote to me recently about the following problem:

“ I am having problems with the boom on my crane creeping down. How do I determine if it’s the valve or cylinder that’s leaking?”

A popular misconception about hydraulic cylinders is that if the piston seal is leaking, the cylinder can creep down. Fact is, if the piston seal is completely removed from a double-acting cylinder, the cylinder is completely filled with oil and the ports are plugged, the cylinder will hold its load indefinitely - unless the rod-seal leaks. What happens under these conditions - due to the unequal volume either side of the piston, is fluid pressure equalizes and the cylinder becomes hydraulically locked. Once this occurs, the only way the cylinder can move is if fluid escapes from the cylinder via its ports or rod seal.

Bijur Delimon International, a global leader in automated lubrication systems for manufacturing equipment, has launched a new web site-- www.luberevolution.com-- dedicated to the needs of the packaging, bottling and process industries.

The purpose of the site is to give engineers access to an interactive tool they can use to explore a variety of standard and innovative lubrication solutions offered by Bijur Delimon International. It only takes a minute or two to enter the type of lubricator (pneumatic, electric, manual, single-point), lubrication metering device (series progressive block or injector) and the number of points they need to lubricate. Then the tool generates a system ideally suited to these requirements.