Maintenance Technology April 2015 - (Page 22)

HYDRAULIC-SYSTEM TIPS It's important to develop a preventive maintenance schedule for every hydraulic system in your plant, and stick to them. This can help your operations boost the efﬁciency, safety and uptime of these critical plant systems. Another check involves watching the system pressure gauge while the equipment is operating. Normally, the pressure shouldn't drop more than 100-500 PSI when the accumulator is properly pre-charged. If piston accumulators are used, the charging rig should be installed when the system is down and the oil bled off the top of the piston. With the pump on and the bleed-valve open, there should be little or no flow exhausting out of the valve. Make sure all personnel are away from the bleed-valve prior to turning the pump on. A continuous flow from the bleed valve would indicate that the piston seals or barrel were badly worn. If no flow exists, recharge the accumulator to the proper dry nitrogen level. because of a poor crimp or the hose is rubbing on a beam or another hose. If rubbing cannot be avoided, hose sleeves are available on a reel from various manufacturers. Hoses should usually not exceed approximately 4 ft. in length unless they move with a machine. Also inspect system piping to verify that prior to connecting to a valve bank or cylinder, a hose is installed. The hose will absorb the hydraulic shock that is generated when the oil is rapidly deadheaded. An exception to this rule is that hard piping should always be used when connecting to a vertical or suspended type load. Pilot-operated check valves and counterbalance valves are used to hold the load in the raised position. Hoses Inspect system clamps to verify that that the proper hydraulic clamps are used to clamp hydraulic lines. Beam and conduit clamps are not acceptable, as they will not absorb the shock generated in the piping or tubing. The clamps should be spaced approximately 5 ft. apart. A clamp should also be installed within 6 in. of the pipe or tubing termination point. Check system hoses for proper length and wear. Hoses infrequently burst because the rated working pressure is exceeded. They normally rupture Reduce Maintenance Cost by up to 40% Keeping oil clean - It's your best insurance! 1 2 Keep oil clean - remove solids AND moisture Valve testing Typical new oil. Clean incoming oil - because new is NOT clean oil Keep your ﬁrst ﬁll from starting things off on a dirty foot. Our systems remove impurities in your new oil. These contaminants are the seeds of increased maintenance costs in the form of downtime, wear, and repair. A Harvard Filtration system on your machinery will keep your investment clean and operating at its peak performance. In hydraulic systems, 70-80% of failures are due to contamination. The Harvard Constant Contamination Control® keeps moisture and contaminants from accumulating in your oil. This prevents premature wear, and reduces costs. Let us show you how one company reduced their maintenance costs by 40%. Call us today. Don't let your oil look like this! Contaminated oil. The same oil after 48 hours in use with a Harvard system. 505 Union Street l Evansville WI 53536 l 800-523-1327 608-882-6330 l 608-882-5127 fax www.harvardcorp.com 22 | MAINTENANCE TECHNOLOGY Clamps Constant Contamination Control® can be applied to engines, transmissions, hydraulics, turbines, gear boxes, diesel fuels, heat transfer ﬂuids, AND MORE! On any hydraulic system, one or more valves could be closed while the system runs. These include relief valves used with pressure-compensating pumps, air-bleed valves and accumulator-dump valves. The tank lines of all valves should be checked regularly with a temperature gun or infrared camera to verify that they are closed and no oil is being lost back into the reservoir. The big picture To improve the reliability of your equipment, Smiley says it's important to develop a preventive maintenance schedule for every hydraulic system in your plant, and stick to them. Heeding this advice can help your operations boost the efficiency, safety and uptime of these critical plant systems. MT Al Smiley is President of GPM Hydraulic Consulting (gpmhydraulic.com) of Monroe, GA. APRIL 2015 http://www.harvardcorp.com http://www.gpmhydraulic.com http://www.harvardcorp.com

Maintenance Technology April 2015

Table of Contents for the Digital Edition of Maintenance Technology April 2015