It is estimated that around one-fourth of the compressed air in an average system is lost to leaks. This is a costly waste of energy, given the expense of operating compressors, and it is something that can be prevented in most situations. Most compressed air loss occurs at the joints between pipes, and it is often due to inadequate threaded connections or other failing connectors. The relatively-recent innovation of pressed fittings are a solution for leaky joints between air pipes, and below is how to install them in your system:
Tools and materials needed
Pressing tool with matching jaws – there are several manufacturers of pressing tools, and they are powered by variety of energy sources: alternating current, battery direct current, and compressed air. In addition, press jaws that match various diameters and pipe materials are also available. It's important that you use a tool with jaws that will adequately compress the fitting; check with tool and fitting manufacturers to determine the particular specifications that will match your needs.
Press fittings – as with any air fitting, press fittings come as elbows, 45 degree connectors, couplings, tees and other configurations. However, press fittings contain flared ends that contain an internally-mounted seal made of plastic, rubber or other materials. When choosing fittings, it is important to find a match with your compressed air pipe. Matching by material, size, and shape must all be considered during the decision-making process.
Compressed air pipe – you can utilize existing pipe if it is in sound condition, or you can replace pipe with new sections.
Pipe cutter or saw
Black marker or scratch awl
How to install press fittings
1. Cut the pipes to length – if you are using new pipes, then you will need to cut them to the appropriate length with a pipe cutter or saw. With existing pipe, cut away threaded ends or welded joints to expose clean edges. Be sure to make your cuts at a 90 degree angle so that pipe ends will abut and form a tighter connection.
2. Debur and clean the pipe ends – sharp or jagged cuts can damage the soft seal inside press fittings, so use a deburring tool to smooth and taper the ends of pipe. After deburring, thoroughly clean the ends of the pipes to remove grease, dirt or other contaminants.
3. Test fit the pipe sections – spray the ends of each pipe section with a silicone lubricant, and push the pipe sections together inside the fitting to test the joint made. After achieving a solid-feeling joint, mark the pipes with a marker or scratch awl along the edge of the fitting to indicate how far the pipes should be inserted; remove the pipes from the fitting once you make the marks.
4. Prepare the pressing tool and jaws – following the tool manufacturer's directions, prepare the pressing tool and adjust the jaws for your specific application.
5. Press the joint – after the pressing tool is adjusted and ready for use, re-insert the pipe ends into the fitting until the marks you made in step 3 are lined up with the edges of the fitting. Place the pressing tool on top of the fitting flare, and line it up until it is centered over the flare. Making sure the pipe is still aligned, squeeze the jaws to compress the pipe so the seal is pressed tightly around the pipe. Repeat the process at the other end of the fitting with the opposing section of pipe.
6. Test the joint – once you have pressed the new joint, you can immediately test the fitting to determine if it will hold up against the pressure. Be cautious when first adding compressed air to the system in case the joint is not firmly sealed.
For more information on different types of seals, check out companies like Phoenix Specialty.