Pneumatic components and systems normally require very little maintenance. Regular inspections with minor adjustments are a form of preventive maintenance and will prolong the operating life of most pneumatic controls.
The following schedule is intended as a guideline. Experience and operating conditions will determine actual schedules. Refer to OEM datasheets for specific maintenance instructions.
|Drain air line filters. Check operation of the water traps.||Weekly, or more often as needed|
|Check for and seal air leaks.||Every four weeks, or more often as needed|
|Add lubricant to mist lubricators.||Every four weeks, or more often as needed|
|Externally clean components and actuators.||Every four weeks|
|Lubricate cylinders and pivot points. Check and adjust component movements.||According to mechanical maintenance recommendations|
|Replace air filters.||Every six months|
|Replace or clean plugged silencer.||As needed|
When cleaning, do not use cotton waste or other cloths that have lint. When changing a cylinder, plug the hose ends to keep impurities out.
When cleaning pneumatic cylinders, give special attention to blind ends and piston rods with links.
Usually seals are the components most subject to premature wearing. A seal wears out prematurely or is damaged for the following reasons:
If valve or cylinder seals have to be renewed, lubricate them and the slide surfaces of the components with silicon or paraffin grease. Be careful not to apply too much lubricant since too thick a layer will get “lumpy,” which may prevent proper functioning of a seal.
DO NOT use Molykote-type grease. It contains hard particles. Such grease causes seals to wear out quickly. Also, the rubber particles soak up lubricant.
Valmet recommends using any of the following greases:
Make sure that oil mist lubricators are correctly adjusted and filled. Excessive lubrication added to compressed air is unnecessary and can even be detrimental in some instances.
When selecting oil for fog oil lubricators, it is recommended that the viscosity range is 9 to 11 mm 2/3 (=cSt) at 40 °C and ISO-Class VG 10 S as per ISO 3448.
Valmet recommends using any of the following oils for fog oil lubricators:
It is important to pay attention to compressed air leaks. Any leaks may cause improper operation of components.
Depending on the type connection, you can use gaskets or an appropriate Loctite compound for leaks. If using adhesive compound for a leak, keep the circuit depressurized until the compound has completely cured.
For more information on pneumatic maintenance, contact your Valmet representative or check out Valmet's training services.