Copyright Goodheart-Willcox Co., Inc. Chapter 16 Conditioning and Distribution of Compressed Air 417 • Pressure regulators commonly use a fl exible diaphragm to sense outlet-line pressure and provide the balancing force needed to control airfl ow through a poppet valve. A diaphragm- control chamber may be used to separate the regulator side of the diaphragm from direct contact with outlet port airfl ow. This arrangement dampens the reaction of the diaphragm, providing more sensitive and effi cient workstation pressure control. • Lubricators meter oil into pressurized system air at the workstation to provide lubrication for system valves, actuators, and air-powered tools. • Conductors moving compressed air through a distribution system can be grouped into two general classes: rigid and fl exible. Pipe is the most common rigid conductor, and hose is the most common fl exible product. • Conductors must be sized and assembled properly to produce system lines that transport compressed air from the compressor to the system actuator with a minimum of pressure drop. Tables are available in engineering handbooks and other publications that provide data on air pressure loss in standard rigid and fl exible conductor sizes using various fl ow rates. • Hose selection, application, and maintenance is critical in both fi xed and portable systems to assure air distribution with a minimum loss of pressure. Internet Resources The following are some useful resources available on the Internet. Enter a company or organization name into a search engine to access its website. Explore the various areas of the sites to discover useful fl uid power resources. Condit Company. The web page provides information on the importance of air fi ltration for pneumatic systems, and includes a number of links to discussion of other system functions. The product brochure provides detailed information on one series of pneumatic fi lters. eCompressedair. Discusses the piping system involved in a pneumatic system, including illustrations with details concerning the total air distribution system. A number of links are provided to related topics, such as the compressor and air- quality control. CompAir (Gardner Denver, Inc.). FAQs regarding air treatment in compressed air systems. ABAC Air Compressors. Describes the function and operation of the aftercooler, separator, and automatic condensate drain for large compressor units. Summary • Maximum pneumatic system operating effi ciency is achieved when system compressed air is consistently clean, free from moisture, and at a relatively uniform temperature. • Dry, oil-wetted, and oil-bath fi lters on the intake line of pneumatic compressors remove dirt and dust from atmospheric air. • Because changes in temperature affect air pressure and volume, it is important to monitor the temperature of the intake air and the compressed air moving through the system. In addition, temperature infl uences the ability of air to retain water vapor. • Water vapor in air is referred to as humidity. When the temperature of the compressed air drops to the dew point, the vapor condenses into liquid water. • Liquid water in a pneumatic system can wash away lubricants, increase component wear, cause inconsistent system operation, and lower the fi nished quality of products using the air directly in the manufacturing process. • Locating the air intake of the compressor in a protected area cooling the air below the dew point to condense, collect, and remove liquid water in system components and installing specifi c air dryers between the system receiver and distribution lines are all methods to reduce moisture in the pneumatic system. • The receiver is typically a metal cylindrical tank with domed ends, inlet and outlet ports, and an internal baffl e that ensures that any particles or liquid water fall out of the airstream. • The receiver stores compressed air for use in the pneumatic system, dampens system pressure pulsations, removes water vapor, and may serve as the mount for the system prime mover and compressor. • The size of receiver needed for a pneumatic system depends on the cubic feet of free atmospheric air needed per minute and the desired cycle time, as well as the atmospheric, initial receiver, and fi nal receiver air pressures. • The pressure regulator maintains a consistent pressure for use by workstation tools and circuit actuators. The unit is necessary as the air pressure in the distribution line fl uctuates because of varying air demands and the inherent characteristics of compressor capacity control systems. • Pressure regulators range from direct-operated regulators to pilot-operated units that can be controlled from a remote location.