COMPRESSED AIR DISTRIBUTION SYSTEMS

Transcription

1 Series COMPRESSED AIR DISTRIBUTION SYSTEMS 18

2 DESIGNING AN EFFICIENT COMPRESSED AIR DISTRIBUTION The main source of inefficiencies and problems affecting compressed air distribution systems is often the distribution plan of the system itself. The majority of problems therefore usually occur somewhere between the compressor and the application points. Most compressed air networks are usually of either of two types: Dead-end network Octopus network neither of which provides the best results DEAD-END NOT RECOMMENDED In a dead-end network, air flow must be sacrificed (quantity of air per minute) in order to preserve a uniform pressure at the point of use. The progressive reduction of the central pipe while it moves away from the compressor maintains pressure. However, air tools and equipment must be placed along the length of the circuit in decreasing order of consumption (SCFM). The equipment using the most air flow must be located near the compressor, and that using less, further away. This type of network is not recommended. S CONVENTIONAL OCTOPUS WORST SITUATION OCTOPUS A network where each additional line and extension does not necessarily match the initial configuration is often called an octopus network. Dead-end networks often evolve into octopus networks over time. The octopus network includes the following anomalies: Different airline materials Curves, reductions and enlargements without apparent reason Inconsistent diameters of air lines Installation done with no knowledge of pneumatic standards Predicting what flow and pressure are available at any point is virtually impossible. Air flow fluctuations from varying usage of pneumatic equipment and air tools makes it even more difficult to get the right pressure and flow at any given point. This results in varying pressure and air flow conditions through out the system, creating many problems. This type of network, while quite common, is the worst possible situation. 19

3 S NOT RECOMMENDED WORST SITUATION More than 98% of factories using compressed air started out with a dead-end network. Over the years, their systems have come to resemble a giant octopus whose growth reminds us of a monster escaping our control. THE PROBLEM At the very least, the dead-end network they have has sacrificed air flow in order to maintain point of use pressure. 20 CONVENTIONAL OPTIMAL OCTOPUS The equipment located at point A demonstrates that the air supply flows through several lines at a time, providing balanced pressure and air flow. The secret to planning an efficient, problem-free distribution network is actually quite simple. The goal is to achieve a balance between flow and pressure to maintain the ideal situation at all points of use, while providing for future expansion and remaining flexible in the face of varying compressed air needs. A closed loop network allows the air supply to flow through several lines at a time to any given point on the network. The balance between pressure, air flow and stability of supply is ensured by using a single diameter for piping. This type of system will also easily accommodate modifications and can easily supply tools and equipment with varying supply requirements anywhere on the network. Ball valves permit the isolation of a particular portion of the air line network to allow for easy: Repairs Connections Enlargements Periodic maintenance A well-built closed loop network is therefore most often the ideal situation for the distribution of compressed air. In addition to being easy to plan and to modify when needed, this type of distribution system becomes an immense compressed air reservoir that: THE SOLUTION How is this balance achieved? Often, the best solution remains the CLOSED LOOP design. CLOSED LOOP The size of each loop does not need to be uniform. The important thing is to have at least two different supply routes available simultaneously for each feeder pipe descending toward a tool or piece of equipment. This type of network is often the ideal situation for compressed air distribution systems, providing the balance between flow and pressure required to provide the most efficient distribution of compressed air. THE SOLUTION Offers more constant air flow at all times Guarantees more uniform pressure through out Contributes to the life of the compressor by limiting running time Reduces the electrical consumption of the compressor

4 PROPER SYSTEM DESIGN SYSTEM DESIGN System design should start with a layout of the shop or plant. Designate where and what tools will be used. Determine the placement of the main line. Try to keep the line as short as possible while providing access to where tools are used. Try to keep in mind any future needs or alterations. It is much easier to make changes if they are planned for. Drop supply lines at the point of use or at regular intervals, to minimize hose length. Size the lines appropriately for the equipment to be used. Each supply line should be installed with at least a filter and regulator. FRLs should be installed at the point of use, allowing the air to be prepared properly for the application. Designate appropriate supply lines as clean air lines for use with paint guns, blow guns or tire inflator gauges. On lines operating air tools, install lubricators to extend tool life. PROPER SLOPES AND DROPS A properly designed system can offer cleaner air of the appropriate volume and pressure, translating to better tool performance and worker productivity S As for the slope of network pipes, either for lines running along exterior walls or within a building, there should be a minimum inclination of 1 inch for every 100 feet of length (1 to 2 %). This will lead any condensation toward water evacuation points. It must be noted that the feeder pipe may perform both functions: air flow and the elimination of condensed liquids. Secondary pipes attached below the main pipes should include a ball valve and will help eliminate condensation at their feet by the presence of evacuation valves. Main line slope: 1 inch for every 100 feet of run (always in the same direction as the air flow) Water Trap Tee Pre-formed Pipe Ball Valve Y Strainer Lowest Point of the Main Line Pipe Clip Automatic Drain PROPER DISTRIBUTION SYSTEM INSTALLATION Properly installed pipe minimizes the amount of moisture at the point of use. Piping should slope in the direction of the air flow to an accessible moisture drain point Outlets should be taken from the top of the main air lines to keep moisture out Assemble and test for leaks one section at a time to avoid major disassembly later Pipe unions should be installed at regular intervals. This makes future repairs and modifications easier Sealant should always be used on threads to eliminate air leaks Tapered threads should not be overtightened as this could cause the fitting to crack Air lines should be secured to a solid surface using pipe clamps All piping and fittings should be checked regularly to avoid leaks in the system. An air leak will reduce the amount of air at the tool, causing pressure drop. It will also cause the compressor to work longer and harder, increasing energy and maintenance costs (refer to the next page) 21

5 S SIZING A COMPRESSED AIR LINE Correct sizing of the air line is essential to maximize the cost effectiveness of the compressed air distribution system. Network line size is determined by the flow capacity required for the tools and equipment to be supplied, as well as by system design and length. THINGS TO CONSIDER: Pressure drops are totally unrecoverable and waste energy; a drop in pressure from 87 to 73 PSI will decrease machine and tool capacity by up to 27% Energy cost will rise by 10% if pressure is increased by 20 PSI to compensate for pressure drop Pipe fittings are responsible for much of the pressure drop in compressed air systems TYPES Flow capacity is a function of total network length; longer lines require larger diameters to maintain the same flow and minimize pressure drop. The type of network used will also have an impact on line size. There are two basic types of network designs: closed loop and linear/dead-end. Both are commonly used for compressed air networks. CLOSED LOOP Pipe size should therefore be large enough to keep pressure drops between the reservoir and the point of use to a minimum Main line size should never be smaller than the compressor outlet size Branch line size should be determined based on length and total consumption of the tools on the branch LINEAR/DEAD-END Main lines that are too small will cause high air velocity, thus making water separation more difficult A larger main line is in fact advantageous, acting as a reservoir for the air, reducing the load on the compressor and providing capacity for future demand and growth C C Two paths to point C Half of the compressor flows in each path Allows for smaller diameter size of network Diameter size of network - to point total length C - determined by BEFORE EVALUATING TOTAL LENGTH In order to calculate an effective length of the total network, fittings used must also be taken into account. Every direction change, cross manifold, T connection or reduction in line size within the network will cause pressure loss equivalent to adding additional line length. The table below indicates effective lengths added to the network by each of these restrictions and/or connections. EQUIVALENT LENGTHS FOR VARIOUS FITTINGS (IN LENGTH OF EQUIVALENT TUBE) Union FITTINGS DIAMETER OF FITTINGS 15 mm 20 mm 22 mm 25 mm 28 mm 32 mm 40 mm 50 mm 63 mm 0.43" (0.13m) 0.49" (0.15m) 0.56" (0.17m) 0.66" (0.20m) 0.72" (0.22m) 0.82" (0.25m) 0.98" (0.30m) 1.31" (0.40m) 1.64" (0.50m) 90 Elbow 1.15" (0.35m) 1.31" (0.40m) 1.41" (0.43m) 1.64" (0.50m) 1.80" (0.55m) 1.97" (0.60m) 2.62" (0.80m) 3.12" (0.95m) 4.10" (1.25m) T Straight Line T Deviation 0.56" (0.17m) 0.66" (0.20m) 0.79" (0.24m) 0.98" (0.30m) 1.12" (0.34m) 1.31" (0.40m) 1.64" (0.50m) 2.30" (0.70m) 3.12" (0.95m) 1.80" (0.55m) 1.97" (0.60m) 2.20" (0.67m) 2.62" (0.80m) 3.08" (0.94m) 3.61" (1.10m) 4.59" (1.40m) 5.58" (1.70m) 7.55" (2.30m) Reducer 0.59" (0.18m) 0.66" (0.20m) 0.72" (0.22m) 0.82" (0.25m) 0.98" (0.30m) 1.15" (0.35m) 1.48" (0.45m) 1.97" (0.60m) 2.46" (0.75m) 22

6 THE SOLUTIONS compressed air piping systems in either Nylon or Aluminium are put together using non-traditional means such as push-in fittings or compression fittings. These assembly methods speed up the installation process by as much as a factor of 4, saving on installation costs that often include more labour than materials. The choice of Nylon or Aluminium air piping system provides great improvements over traditional conventional materials, such as Iron, Galvanized Steel and Copper, by eliminating corrosion problems that plague traditional systems. This ensures much longer useful life, definite improvements in flow and reductions in operating costs. air systems are also very light, reducing the time and effort required to complete installations and reducing strain on workers. 63 mm 50 mm 40 mm 32 mm 28 mm 25 mm 22 mm 20 mm 15 mm COMPRESSED AIR SYSTEMS Series AIR LINE Nylon piping Series Aluminium piping Series QuickLINE Aluminium piping S PIPING DIAMETERS AVAILABLE PIPING 15 mm 20 mm 22 mm 25 mm 28 mm 32 mm 40 mm 50 mm 63 mm Series AIR LINE Nylon Series QuickLINE Aluminium Series Aluminium 23

7 S COMPRESSED offers 3 compressed air distribution systemsto meet the needs of users: Series AIR LINE Series QuickLINE Series SERIES FITTINGS Series AIR LINE Nylon Piping Series Composite (Acetal) push-in Series QuickLINE Aluminium Piping MAXIMUM PRESSURE (PSI) 175 (PSI) 12.5 (BAR) DIAMETER (MM) 15, 22, 28 Series 220 (PSI) 15.3 (BAR) 15, 22, 28 Brass push-in Series 220 (PSI) 15.3 (BAR) 40, 50, 63 Brass compression Series Aluminium Piping Series 181 (PSI) 12 (BAR) 20, 25, 32, 40, 50, 63 Fiberglass reinforced polyamid plastic screw-type 24

8 For more information on 's compressed systems, the following brochures can be downloaded at.com AIR LINE COMPRESSED AIR DISTRIBUTION SYSTEM COMPRESSED AIR DISTRIBUTION SYSTEM QuickLINE COMPRESSED AIR DISTRIBUTION SYSTEM Series Series Series Highlights features and benefits of each series Useful information for planning an optimal network A selection of accessories essential to a compressed air network Visit.com Section «Technical Support» / Air Distribution Systems 25