It is said that a chain is only as strong as its weakest link. This idea applies to many things in life. Air tools and equipment are no exception. Today’s pneumatic equipment is far superior in many ways to equipment made just a few years ago. There are lighter materials and better designs, resulting in tools that are faster, quieter and more powerful pound for pound than the tools of yesterday.
There is, however, one common denominator between today’s air tools and ones made years ago. The element that all these tools need, which is many times overlooked or taken for granted. Here is a riddle for you: If a gasoline engine can’t run without gasoline, then what does an air tool need to operate? You guessed it! Air! Pneumatic tools need air that is clean, dry, and the correct pressure and volume in order to perform the way they were designed.
This presents two different issues. One is the actual creation of the air. This, as you know, is dependent on having a compressor (or compressors) that is correctly sized to supply air to the shop. It needs to be large enough to supply the pressure and, more importantly, the volume needed for the number of bays, technicians and equipment in a shop. This needs to be balanced against the economics of operating the equipment as well as the initial costs. Too big or too much air is wasteful in terms of operating costs and purchase/installation costs. The second issue, and the one this article is about, has to do with getting the air from here to there. After the air leaves the compressor, and makes its way to the bay, the technician is still faced with making the connection from the wall fitting to the air tool. The only way to do this is using an air hose.
There are two styles for air hose in terms of storage. The first is the original and oldest form — bulk hose. This is loose hose, coiled until needed and then stretched out and laid on the shop floor. This solution is the least expensive, but with the low expense comes some built-in frustrations and failures. Air hose that is on the ground is constantly dirty and it’s more prone to damage such as cuts, crushing, etc. Air fittings on loose hose tend to fail sooner and leak more often due to dirt and contaminants.
The alternative to loose air hose is to use a hose reel. Reels come in many configurations and materials, but the basic design allows the user to remove only as much hose as is needed to reach the work area. I will go into detail about different designs and feature benefits a little later.
The earliest hoses were more accurately tubes or reeds. Long, hollow plant reeds such as bamboo and other plants were used to transport water for irrigation of crops. Modern-day hoses evolved from those designs, the earliest of which were based on natural rubber, and hoses continue to be offered in that material today. Rubber air hoses have improved over the years, with manufacturers implementing various methods such as using interwoven thread and coatings both internally and externally.
Rubber air hose is still extremely popular, but does have some shortcomings. It is heavy, it tends to get dirty and stay dirty, and it is larger in outside diameter than other types of hose. There are several alternatives to rubber. PVC or poly-vinyl chloride hose is one such alternative. This style hose is lighter than rubber hose, can be dyed multiple colors, and is resistant to chemicals and staining. The disadvantage of PVC hose is that is can become stiff and hard to manage in cold weather.
PVC hose does lend itself well to being formed into coil hoses. Usually suspended from the ceiling, these hoses have a memory to them and return to their coiled shape after being stretched out. They can range in length from 10’ up to 25’ or longer.
Air Hose Reels
Hose reels have been around for many years. The earliest reels were metal or wooden spools. The hose was rolled back onto them manually. These reels still exist today although they are pretty much always metal in construction. They range from a spider-type spool, which is basically two crosses of metal, to the more complex metal reels with solid sides. Manual hose reels are good solutions for low usage, places where cost savings are the most important thing, and in some harsh environments that may destroy automatic hose reels.
Top-end hose reels are fully automatic in their retraction. There are two types of automatic hose reels: there is what is known as open design and closed or cage design. The only difference is on the closed design the reel that holds the hose is covered by an outer structure known as the cage or box. While this is mostly a cosmetic consideration, the cage does provide some protection from atmospheric dangers including chemicals, sun, moisture, fumes, etc.
The cage can be made out of metal or plastic. Both designs are extremely durable and will offer, in most cases, a lifetime of service. The only exception might be on service trucks that are in corrosive environments such as mining. In those cases, the plastic architecture may be a better solution.
The real meat of the hose reel is the rewind mechanism. Although a seemingly simple device, these are fairly complex, have several moving parts and can be problematic. Most manufacturers will tell you that the return mechanism will never need replacement or service. While this is true a majority of the time, the best manufacturers offer field serviceable return mechanisms. In some cases, these are cartridges that can be replaced by the owner user (assuming said owner has a really tall ladder!). Some hose reels are not serviceable at all or, if they are, the owner will be risking life and limb to replace the return spring, which is the main failure item on a hose reel.
I mentioned in the beginning of this article about the weakest link in a chain. While sometimes the air hose and reel can be the weakest link to power tools, they don’t have to be. Generally speaking, hose and reels are abused, ignored and taken for granted. In many cases, the cost difference between average and good quality is minimal, but the additional years of service for the user can be significant.