October 3, 2011
Keep your hydraulic hammers in good working condition by following these six basic maintenance recommendations.
by Randy Osborne
In recent years, hydraulic hammers have made great strides in performance and reliability, providing excellent return on investment over traditional mechanical/explosive alternatives, if properly maintained. The downtime and cost per hour of operating any hydraulic hammer can be reduced by following the recommendations set forth by the manufacturer, but here are some basic maintenance recommendations that can help you keep your hammer in good operating condition.
1. To get off to a good start, match the hydraulic hammer to a suitable base carrier such as an excavator, rubber-tired backhoe, or a stationary boom system.
2. Be sure the hydraulic flow and pressure settings are correctly set. At least once a year, the hydraulic flow, maximum hydraulic relief pressure, and hammer operating pressure should be checked and calibrated to original specs. Depending on the changes in ambient temperature, the viscosity of the hydraulic oil must be adjusted to match ambient working temperatures. Cold temperatures reduce the efficiency of the sealing devices on the nitrogen rebound system, and, thus, pressure settings need to be checked more frequently. In addition, the viscosity of the hydraulic oil increases along with wear during cold operation.
3. In most cases, the operator is expected to perform basic inspections and perform minor maintenance requirements on the hydraulic hammer. The pre-start check should be performed before every shift to ensure that all the components are in proper working order. Ideally, the operator should check to see if there are any oil leaks, that the hydraulic hoses are in good condition, and that there are no signs that a hose is ready to fail. Be sure to check that all fasteners are in place and tight. Make sure the hammer is being properly held in the side plates or box housing and that it is not loose. The operator should lubricate the tool with approved grease suitable for this application. General purpose grease does not provide sufficient protection between the tool and tool bushing and will result in rapid wear of both components. If the hammer is not equipped with an automatic greasing system, the operator will need to repeat the lubrication of the tool several times during the shift, whenever the protection film of grease is lost between the tool and the tool bushings.
4. It is recommended that the tool be removed from the hammer every two weeks so that an inspection can be carried out on the retainer pins and the upper end of the tool to check for any signs of unusual wear.
5. The nitrogen gas in a hammer should be checked and adjusted only by a qualified service person, as the nitrogen gas is in a high-pressure state and specific training is needed to deal with it safely. The nitrogen gas should be checked on a schedule recommended by the manufacturer, but more frequent intervals are recommended in cold temperatures. Telltale signs that the nitrogen pressure is getting low or lost completely include lack of hammer hitting power and violent jerking of the hydraulic hoses.
6. At least once per year, the hydraulic hammer should be completely disassembled, resealed, and new tool bushings installed, if required. Using approved quality replacement parts can ensure longer hammer life. While doing a rebuild on the hammer itself, it is also recommended that the box housing be refurbished with new upper and lower isolators and the dampers should be replaced or shimmed as needed. Due to the wide variation of operating conditions encountered by hydraulic hammers, it is usually necessary to adjust the maintenance periods accordingly, as some applications can be more severe. AM
Randy Osborne is a product applications specialist with BTI Breaker Technology Ltd.
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