Pneumatic cylinders come with a whole range of variable attributes, from size to load and speed capacity as well as options on port locations and mountings. There are also considerations around the design and type of pneumatic cylinder you want in relation to the application and its working environment. Below, we unfold some of the choices to be made when choosing cylinders, and provide a little guidance on which ones are suitable for which application.
Single- or double-acting cylinder?
One of the first considerations when looking at pneumatic cylinders is to decide whether a single-acting cylinder is right for your application, or whether a double-acting cylinder would be better suited. Single-acting cylinders have just one air port, and uses the pressure input at this point to move the piston to the pre-determined final position. The piston is then returned to the starting position using an internal mechanism – usually a spring, though sometimes the weight of the load itself combined with the effects of gravity. Double-acting cylinders have an air port at each end of the cylinder, using air alternately at the two ends to push the load in the required direction. This means that a single acting actuator can only do work in one direction, whereas double-acting cylinders carry a full load in both directions (up and down/forward and backward). Double acting cylinders require more energy, but are suited to a load that requires both pushing and pulling, for example, opening a gate.
Other factors which determine the right pneumatic cylinder for your application:
How much work you need the pneumatic cylinder to do
The intended load for cylinders dictates, to a large degree, both the cylinder type and the piston size. It is critical that the cylinder is large enough to create the required force needed to carry the load, whilst also compensating for friction and losses; if you oversize the cylinder you will end up with increased energy costs and a larger and unnecessary outlay cost.
How fast you need your pneumatic cylinder to move
The speed at which a pneumatic cylinder carries a load depends not only on the load itself, but also the pressure available from the compressor, the bore size, the size of the piston rod and the distance which must be covered. There is a balancing act to be done here; higher travel speeds result in greater pressure losses, seemingly calling for increased pressure – but over-pressurised cylinders will suffer damage and increase energy consumption. Heavy loads and long stroke lengths also don’t mix well unless cylinders are large enough to cope – though the mounting position of the load can help in such cases.
Where the pneumatic cylinder will be working
If space is tight, compact cylinders are often a good choice, as they fit into smaller spaces. However, they also tend to have shorter stroke lengths because their overall design won’t facilitate a load to be carried over a longer distance. If the pneumatic cylinder is likely to be working in extreme conditions, either in very high or very low temperatures or where it will come into contact with corrosive media, the manufacturing material may need to be carefully selected; cylinders are generally made in steel, aluminium, brass or engineered plastics, or a combination of materials – choosing a suitable material for your working environment is critical. Similarly, the sealing materials used for your pneumatic cylinder will also need to be appropriate for the working environment in order to protect the internal workings and ensure longevity of the equipment.
There are a whole range of variables to consider when selecting a pneumatic cylinder best suited to your application. Matara are seasoned experts in pneumatic systems and will be happy to guide you in selecting the appropriate configuration from all the options available. If you would like some guidance in selecting the right pneumatic cylinder, speak to the experts at Matara on 01684 850 000.