The AN thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It is a US military-derived specification that dates back to World War II and stems from a joint standard agreed upon by the Army and Navy, hence AN. The Army-Navy involvement is also the origin of the red/blue color combination that was traditionally used in the anodized finishing process.
AN sizes range from -2 (dash two) to -32 in irregular steps, with each step equating to the OD (outside diameter) of the tubing in 1⁄16-inch increments. Therefore, a -8 AN size would be equal to 1⁄2-inch OD tube. However, this system does not specify the ID (inside diameter) of the tubing because the tube wall can vary in thickness. Each AN size also uses its own standard thread size.
AN fittings are a flare fitting, using 37° flared tubing to form a metal-metal seal. They are similar to other 37° flared fittings, such as JIC, which is their industrial variant. The two are interchangeable in theory, though this is typically not recommended due to the exacting specifications and demands of the aerospace industry. The differences between them relate to thread class and shape (how tight a fit the threads are), and the metals used.
Note that AN threads are different for bolts and fittings. In bolts the number refers to the diameter of the bolt whereas in a fitting it refers to the OD of the tube and thereby have different threads. For example, AN6 bolt has a 3⁄8-24 thread whereas an AN6 fitting has a 9⁄16-18 thread.
Note that 37° AN and 45° SAE fittings and tooling are not interchangeable due to the different flaring angles. Mixing them can cause leakage at the flare.
Originally parts were made compliant to the specification MIL-F-5509, but they are now controlled under SAE AS (Aerospace Standards) specifications AS4841 through AS4843 and AS4875.
|Tube OD (inches)||1⁄8||3⁄16||1⁄4||5⁄16||3⁄8||1⁄2||5⁄8||3⁄4||1||1 1⁄4||1 1⁄2||1 3⁄4||2|
|Nominal hose ID (inches)||1⁄8||3⁄16||1⁄4||5⁄16||3⁄8||1⁄2||5⁄8||3⁄4||1||1 1⁄4||1 1⁄2||1 3⁄4||2|
|Actual hose ID (inches, approximate)||1⁄16||1⁄8||3⁄16||1⁄4||5⁄16||7⁄16||1⁄2||5⁄8||7⁄8||1 1⁄8||1 3⁄8||1 5⁄8||1 3⁄4|
|SAE thread size||5⁄16-24||3⁄8-24||7⁄16-20||1⁄2-20||9⁄16-18||3⁄4-16||7⁄8-14||1 1⁄16-12||1 5⁄16-12||1 5⁄8-12||1 7⁄8-12||2 1⁄4-12||2 1⁄2-12|
|Pipe thread size (NPT)||1⁄8-27||1⁄4-18||3⁄8-18||1⁄2-14||3⁄4-14|
A flange is an external or internal ridge, or rim (lip), for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel. Thus flanged wheels are wheels with a flange on one side to keep the wheels from running off the rails. The term "flange" is also used for a kind of tool used to form flanges. Pipes with flanges can be assembled and disassembled easily.
American National Standard Pipe Thread standards, often called national pipe thread (NPT) standards for short, are U.S. national technical standards for screw threads used on threaded pipes and pipe fittings. They include both tapered and straight thread series for various purposes including rigidity, pressure-tight sealing, or both. The various types are each named with a symbol and a full name; examples of the symbols include NPT, NPS, NPTF, NPSC, and others.
A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring, wear pad, preload indicating device, locking device, and to reduce vibration. Washers often have an outer diameter (OD) about twice their inner diameter (ID), but this can vary quite widely.
Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurized according to the resistance present. The fluid is controlled directly or automatically by control valves and distributed through hoses, tubes, and/or pipes.
Swaging is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.
A hose clamp or hose clip or hose lock is a device used to attach and seal a hose onto a fitting such as a barb or nipple.
A compression fitting is a fitting used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined, the fittings will be made of one or more compatible materials appropriate for the connection. Compression fittings for attaching tubing (piping) commonly have ferrules in them.
A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.
Flare fittings are a type of compression fitting used with metal tubing, usually soft steel, ductile (soft) copper and aluminum, though other materials are also used. Tube flaring is considered to be a type of forging operation, and is usually a cold working procedure. During assembly, a flare nut is used to secure the flared tubing's tapered end to the also tapered fitting, producing a pressure-resistant, leak-tight seal. Flared connections offer a high degree of long-term reliability and for this reason are often used in mission-critical and inaccessible locations.
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipe is far stiffer per unit weight than solid members.
Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures. "Nominal" refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number. Specific pipe is identified by pipe diameter and another non-dimensional number for wall thickness referred to as the Schedule. NPS is often incorrectly called National Pipe Size, due to confusion with the American standard for pipe threads, "national pipe straight", which also abbreviates as "NPS". The European and international designation equivalent to NPS is DN, in which sizes are measured in millimetres, see ISO 6708. The term NB is also frequently used interchangeably with DN.
A vacuum flange is a flange at the end of a tube used to connect vacuum chambers, tubing and vacuum pumps to each other. Vacuum flanges are used for scientific and industrial applications to allow various pieces of equipment to interact via physical connections and for vacuum maintenance, monitoring, and manipulation from outside a vacuum's chamber. Several flange standards exist with differences in ultimate attainable pressure, size, and ease of attachment.
A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.
In drilling technology, casing string is a long section of connected oilfield pipe that is lowered into a wellbore and cemented. The purpose of the casing pipe is as follows:
JIC fittings, defined by the SAE J514 and MIL-DTL-18866 standards, are a type of flare fitting machined with a 37-degree flare seating surface. JIC fittings are widely used in fuel delivery and fluid power applications, especially where high pressure is involved. The SAE J514 standard replaces the MS16142 military specification, although some tooling is still listed under MS16142. JIC fittings are dimensionally identical to AN (Army-Navy) fittings, but are produced to less exacting tolerances and are generally less costly. SAE 45-degree flare fittings are similar in appearance, but are not interchangeable, though dash sizes 2, 3, 4, 5, 8, 10, 14, and 16 share the same thread size. Some couplings may have dual machined seats for both 37-degree and 45-degree flare seats. Komatsu and JIS fittings have flare ends similar to JIC fittings. Komatsu and JIS both use a 30-degree flare seating surface. The only difference is Komatsu uses millimeter thread sizes while JIS use a BSP thread. JIC fitting systems have three components that make a tubing assembly: fitting, flare nut, and sleeve. As with other flared connection systems, the seal is achieved through metal-to-metal contact between the finished surface of the fitting nose and the inside diameter of the flared tubing. The sleeve is used to evenly distribute the compressive forces of the flare nut to the flared end of the tube. Materials commonly used to fabricate JIC fittings include forged carbon steel, forged stainless steel, forged brass, machined brass, Monel and nickel-copper alloys.
A tube, or tubing, is a long hollow cylinder used for moving fluids or to protect electrical or optical cables and wires.
Copper tubing is most often used for heating systems, and as a refrigerant line in HVAC systems. Copper tubing is slowly being replaced by PEX tubing in hot and cold water applications. There are two basic types of copper tubing, soft copper and rigid copper. Copper tubing is joined using flare connection, compression connection, pressed connection, or solder. Copper offers a high level of corrosion resistance but is becoming very costly.
The Parflange F37 system is a technology from the hydraulic area of Parker-Hannifin, which allows a non welded flange connection of hydraulic tubes and pipes.
A gas cabinet is a metallic enclosure which is used to provide local exhaust ventilation system for virtually all of the gases used or generated in the Semiconductor, Solar, MEMS, NANO, Solar PV, Manufacturing and other advanced technologies.
ASME is a non-profit organization that continues to develop and maintains nearly 600 codes and standards in a wide range of disciplines. Some of which includes the Boiler and Pressure Vessel Code (BPVC), Elevators and Escalators, Piping and Pipelines, Bioprocessing Equipment (BPE), Nuclear Facility Applications (NQA), Process Performance Test Codes (PTC), and Valves, Flanges, Fittings and Gaskets (B16).