Introduction to Fluid Conductors 241

active component

A fluid system component characterized by being a source of activity. Active components such as pumps perform an action on hydraulic and pneumatic fluids.

aluminum

A metal that is silvery white in color and lightweight. Aluminum resists corrosion.

American Society of Testing and Materials

ASTM. An organization that writes and updates specifications for a broad range of materials. The American Society of Testing and Materials provides pressure ratings for fluid conductors.

annealing

To heat a material and then let it cool gradually. Annealing is done to tubing in order to bend it and relieve internal stresses.

brazed

A process in which a filler metal is melted at a temperature above 840°, but below the melting point of the base metals to form a joint between two base metals. Brazed metals differ from welded metals because only the filler metal is melted.

burst pressure

The pressure at which a conductor is expected to fail and burst. Burst pressure is determined by pressure tests conducted by the American Society of Testing and Materials.

cast iron

A metal consisting of iron, over 2.11% carbon, and 1 to 3% silicon. Cast iron offers heat resistance and compressive strength.

conductor

A component that conveys fluids throughout a pneumatic or hydraulic system. Conductors include pipe, tubing, and hose.

contaminants

Any foreign substance that may cause a loss of efficiency or a breakdown in a fluid system. Contaminants can include particles from cutting or chemicals from sealants.

cover

The outermost layer of hose that protects the inner layers from the environment and wear. The cover is made of wire mesh for strength.

diameter

The distance from one edge of a circle to the opposite edge that passes through the center. Round or cylindrical features require diameter measurements.

drilled metal block manifold

A fluid conductor that is drilled to make fluid passages. Drilled metal block manifolds are made of steel, aluminum, or cast iron.

dry seal

A sealing condition caused by the crest of one thread contacting the root of another thread. Dry seals do not allow fluid to leak from a fluid system.

efficiency

A measure of the work output of a system versus the total energy input. An efficient system is able to convert a greater amount of the supplied energy into the intended useful work.

external leakage

The unintentional movement of fluid from a fluid system into the environment. External leakage can be dangerous and detrimental to the efficiency of the system.

failure

When a part of a system stops being able to perform its job. Failures in a system include corrosion, wear, and leakage.

female thread

A type of thread that appears on the inner diameter of a cylindrical part or round feature. The female thread receives and holds the male thread.

fitting

A fluid component that connects, redirects, extends, or terminates the run of a fluid conductor. A fitting can be a piece such as a coupling or an elbow.

flow rating

The volume of fluid that is passing through a given area of a system per unit time. Flow rating can also be measured for an individual component.

fluid

A state of matter that has the ability to flow. Fluids can be liquids or gases.

fluid system

A power transmission system that uses the force of flowing liquids and gases to transmit power. Fluid systems include hydraulic systems and pneumatic systems.

hoop strength

The resistance of a fluid conductor to inside pressure. Hoop strength indicates the ability of a conductor to maintain its structural integrity.

hose

A type of fluid conductor that joins other components, usually in a non-linear fashion. Hose bends and flexes and is the most versatile conductor.

hose

A type of pneumatic fluid conductor that joins other components usually in a non-linear fashion. Hose bends and flexes and is the most versatile pneumatic conductor.

hydraulic systems

A power transmission system that uses the force of flowing liquids to transmit power. Hydraulic systems allow hydraulic machinery to perform work.

inlet port

A one-way valve where compressed air enters a pneumatic pump.The inlet port is the valve through which fluid is drawn into the pump.

inner diameter

ID. The size of a conductor, as measured along a line extending from opposite points on the inner surface and through the center of the conductor.

inner tube

The innermost layer of hose that contacts the fluid. The inner tube is made of rubber for flexibility.

internal leakage

The unintentional movement of fluid from one component to another within a fluid system. Internal leakage is detrimental to the system by hampering efficiency, but it can also be helpful to pnuematic sytems by providing lubrication.

kilopascal

kPa. A metric measurement of pressure. Kilopascal is a unit of pressure of 1,000 newtons per square meter.

laminated manifold

A manifold that is comprised of several layers of metal. Laminar manifolds are usually made of steel.

leakage

The movement of fluid either out of a fluid system or from one fluid component to another. Leakage causes a loss of effiency and often leads to system failure.

leakage

The unintentional movement of fluid either out of a fluid system or from one fluid component to another. Leakage causes a loss of efficiency and can lead to system failure.

male thread

A type of thread that appears on the outer diameter of a cylindrical part or round feature. The male thread is inserted into the female thread to make the connection.

manifold

A fluid conductor that consists of a metal block with multiple integrated channels. Manifolds are designed to conduct fluid in confined spaces.

maximum allowable working pressure

MAWP. The pressure rating that indicates the highest pressure a conductor should experience in service. Maximum allowable working pressure is also referred to as simply working pressure.

minimum bend radius

A value indicating the limit beyond which a conductor should not be bent. Exceeding the minimum bend radius causes a conductor to not perform properly.

modular-block manifold

A fluid conductor that usually supports one valve. A modular block manifold is designed to be used in conjunction with other manifolds and fluid components.

nominal size

The size by which pipe is known and sold in the fluid component market. The nominal size of pipe differs from its actual size.

outer diameter

OD. The actual size of a conductor, as measured along a line extending from opposite points on the outer surface and through the center of the conductor.

outlet port

A one-way valve where compressed air exits a pneumatic pump.The inlet port is the valve through which fluid is expelled from the pump.

passive component

A fluid system component characterized by inactivity. Passive fluid components such as conductors do not perform an explicit action on fluids, but allow fluids to act upon them.

pipe

A type of fluid conductor that joins other components, usually in a straight line and on a permanent basis. Pipe can be made of metal or plastic.

pipe

A type of fluid conductor that may be used to join system components, usually in a straight line and on a more permanent basis. Pipe can be made of steel, stainless steel or several types of plastic.

plugs

A pipe fitting that closes the end of the pipe. Plugs terminate the run of a pneumatic fluid.

pneumatic systems

A power transmission system that uses the force of flowing gases to transmit power. Pneumatic systems most commonly use air to transmit power.

ports

Openings on valves through which fluid can flow. Ports link one device with another.

pounds per square inch

psi. A measurement of pressure. Pounds per square inch is the pressure resulting from a force of one pound-force applied to an area of one square inch.

pressure

The exertion of force upon a pneumatic fluid. Pressure can cause changes to the properties of a fluid.

pressure rating

An indication of the amount of pressure a fluid conductor can withstand. Pressure ratings generally depend on a conductor's wall thickness.

pump

A mechanical device used to move fluids in a hydraulic system. Pumps use suction or pressure in order to operate.

reinforcement

A layer of woven material used to strengthen hose. Reinforcement of hose may have many layers.

safety factor

The ratio of a fluid conductor's burst pressure to working pressure. A safety factor of 5:1 means that a conductor has a burst pressure that is five times greater than the working pressure.

schedule 160

A common pipe designation that indicates the thickness of pipe wall and how much pressure a pipe can withstand. Other schedules include 40 and 80, among others.

schedule 40

The most common pipe designation that indicates the thickness of pipe wall and how much pressure a pipe can withstand. Other schedules include 160, 80, and 10.

schedule 80

A common pipe designation that indicates the thickness of pipe wall and how much pressure a pipe can withstand. Other schedules include 40 and 160, among others.

schedule number

A number that describes the thickness of a pipe wall. Schedule 40 is the most common metal pipe size.

seal

An intentional obstruction designed to keep fluids inside a fluid power system. A seal prevents leakage and contamination.

single-block manifold

A fluid conductor that contains all of the fluid passages and valves of a complete system. Single-block manifolds can be either laminar manifolds or drilled metal block manifolds.

steel

A metal consisting of iron and carbon, usually with small amounts of other elements. Steel is the most common manufacturing metal.

suction

An indication of the amount of fluid a pump can draw in. Suction capability determines the flow rate of a pump.

supports

A mechanical device that fixes and stabilizes the position of a fluid conductor. Supports can guard against vibration.

tapered

Gradually decreasing in size from one end of the object to the other. A tapered thread is the most common type of thread.

threads per inch

TPI. The number of threads in a linear inch. Threads per inch is measured along the length of a workpiece.

tube

A type of pneumatic fluid conductor that joins other components usually in a non-linear fashion. Tubing is made of thin wall steal or flexible plastic and is easily bent.

tubing

A type of fluid conductor that joins other components, usually in a non-linear fashion. Tubing is easily bent and flared.

valves

Mechanical devices that control air in pneumatic and hydraulic system. Valves are primarily used to control fluid systems.

vibration

The fast, back-and-forth movement of an object. Vibration can lead to system failure.

vibration

The fast, back-and-forth movement of an object. Vibration is a physical hazard.

volume

The amount of three-dimensional space that an object occupies. Solids and liquids have definite volume, while gases have indefinite volume.

wall thickness

A value that indicates the thickness of the wall of a conductor. Wall thickness may remain unchanged as outside diameter and inside diameter change.