In many industries and sectors, actuators are among the most important elements of pneumatic applications. The work done converts the energy of the compressed air into a sliding or rotating motion.
The most popular actuators are those that meet the ISO standard.
- ISO 15552 Profile drives, with piston diameters from 32 to 320 mm, with pneumatic shock absorption and magnetic ring.
- ISO 6432 round drives, with piston diameter from fi 10 to fi 32, optionally with pneumatic shock absorption, with magnetic ring. They can be made in a single action version.
- ISO 21287 Compact drives with internal or external thread on the piston rod are available as an option.
Other actors are:
- UNITOP Compact drives, according to the French standard, are slightly smaller than ISO 21287 and also have different mounting hole spacings with internal and external threads. They also have a magnetic ring. Simple action is also available as an option.
- Rotary units – They carry out a rotary movement and are mainly used to drive ball valves or dampers.
- Linear drives – Stemless actuators, the most advanced actuator type, the stroke of these actuators can be up to 6,000 mm.
- Mini cartridge units – single-acting cylinders with piston diameters from 6 to 16 mm. They are actuators with small strokes in a threaded housing.
Like any mechanical element, the actuator is subject to natural wear and tear or can be damaged.
What causes actuators to fail?
In addition to normal wear and tear, improper use or failure to follow the manufacturer's recommendations is the most common cause of damage to actuators.
1. Damage to seals
As a result of leaks, leaks can occur inside and outside the actuator and become noticeable Decrease in power and a characteristic noise caused by air leakage.
Seal damage can be caused by sudden or excessive pressure peaks in the pneumatic load on the actuator as well as lateral forces acting on the moving rod.
Solid contaminants and water in the system also contribute to damage to the actuator and its seals.
2. Mechanical damage
These are the most common types of damage , overloaded or inadequate. This can lead, for example, to the piston rod bending, the thread breaking, the cover cracking or the piston seizing.
The drive can be damaged by the effect of a bending moment on the piston rod or, for example, by a strong mechanical shock.
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Actuator coordination is also important to working conditions such as operating temperature, dust, working environment (e.g. aggressive factors) or cycle speed.
Otherwise, there will be premature wear and associated costs.
Most of the time we choose to regenerate the actuator for financial reasons if our budget is unfortunately limited, which unfortunately is not always a good solution.
The second reason we chose regeneration is: no chance Buying an original unit (or a replacement unit) as it is no longer produced and has been removed from the manufacturer's offering.
What can be repaired or replaced on a regenerated actuator?
The key point is this correct diagnosis of damage and cost estimation, which is a very important topic.
Actuator repair typically includes:
- Replacing aluminum profiles or tubes (gearbox)
- Selection and replacement of seals
- Replacing the piston rod
The remaining corrective actions are:
- Component cleaning (usually dry cleaning)
- lubrication
- Leak test and correct operation of the actuator
- Unwind the piston rod (stainless steel rods only)
Due to the relatively high cost Drive cover If they are damaged, it will be unprofitable to repair them. Therefore, a better solution than repairing is to buy a new pneumatic drive.
Another very expensive element of the repair is the profile, colloquially also the casing. The key element for the profitability of profile replacement is the piston diameter and actuator stroke.
However, if the seals and/or stem need to be replaced, regeneration is recommended and each repair must be done individually.
Most actuators are manufactured to the ISO standard, so many components from different manufacturers are very similar and even the same over time. There is usually no problem with regeneration
However, when we come across an actuator that does not meet the ISO standard, the problem begins and repair is often not possible. This is mainly due to the lack of availability of components and parts.
The Mini and ISO 6432 drives are due to their design not to be disassembled (therefore they have crimp sockets). There is no way to repair them .
Fortunately, these actuators are inexpensive, so the cost of purchasing new ones shouldn't be an issue.
