Hydraulic Terms EF speaks to hydraulic phrases EF and hydraulic glossary. They are common words and phrases used by those involved in hydraulic industry.
Entrained Air This air which is present in a liquid in an undissolved state and the air is in the form of bubbles. If a pump happens to ingest fluid with entrained air, the air bubbles will have somewhat the same effect on a pump as cavitation. Since this is not associated with a liquid’s vapour pressure and can be referred to as pseudo cavitation.
External Gear Motor
The external gear motor has both its meshing gear teeth on their outer
perimeter and the type of gear used is a spur gear.
Filter A device incorporated into a hydraulic system to remove contaminants from the oil.
Filter Bypass Valve If filter maintenance is not performed, pressure differential across a filter element will increase. To avoid this situation a simple or direct acting relief valve is used to limit the pressure differential across a full flow filter This type of relief valve is generally called a bypass valve.
Filter Indicator A filter indicator shows the condition of a filter element. It indicates when the element is clean, needs cleaning or in the bypass condition.
Fire Point The fire point of a fluid is the temperature to which it must be heated to burn continuously after a test flame has been removed. When a petroleum base oil is heated above that temperature enough vapour is given off from the oil’s surface to ignite when a flame is applied and to remain lit after the flame is removed.
Hydraulic Terms EF
Fire Resistant Oil Fire resistant oils are not fireproof they are simply resistant to fire and if heated to a high to a high enough temperature especially when atomized as in a leak. Fire resistance is determined by three test specifications, flash point, fire point and auto ignition temperature. There are four types of fire resistant fluid, water base, water oil emulsion, soluble oil fluid and invert emulsion oil.
Fitting A device for connecting hose or pipe to hydraulic components.
Fixed Orifice A fixed orifice is a reduced opening of an adjustable size. Common examples are a pipe plug or check valve with a hole drilled through its center, or a commercial, factory preset flow control valve.
Flash Point This is the temperature to which a fluid must be heated to give off sufficient vapour to ignite when a test flame is applied. As a petroleum oil or any liquid is heated, vapour is given off, liquid evaporates. With a petroleum oil vapour, once the flame is removed the vapour ceases to burn.
Float Spool A spool valve design which connects all ports to the tank (return) port, usually in a detented fourth position, allowing a cylinder or motor to "float".
low Control Valve A flow control valve when properly used always reduces the flow rate from a pump to an actuator. A typical flow control valve consists of a valve part and movable part. The movable part is a tapered nose rod which is threaded into the valve body. The movable part in our flow control valve is better described as adjustable since no movement takes place while the valve is operating.
Hydraulic Terms EF
Flow Rate The amount of liquid volume that passes a given point in a given time. Flow rate is commonly measured in gallons per minute (gpm).
Fluid Film Interaction between metal surfaces is greatly reduced by having a lubricating film between them.
Fluid Power Energy transmitted and controlled through use of a pressurized fluid.
Fluid Power System The transmission and control of power through the use of fluid pressure.
Foaming As oil returns to a reservoir it should release any entrailed air bubbles which have been acquired in the system. In some systems where leaks are prevalent and/or returning oil is churned up and foams. As a result entrained air is pumped into the system causing spongy, erratic operation, rapid oil oxidation and noise. In more severe cases, oil foam could bubble out of a reservoir creating a cleaning problem.
Foam Test A check for foaming oil is performed y taking a fluid sample. By draining or drawing off fluid from a system’s reservoir, you can tell by sight whether air bubbles are present in the fluid. The samples should be taken as close as possible to the pump inlet line so that a representative sample of what is getting into the system can be taken.
Force A force is any influence capable of producing a change in the motion of a body. It can cause a body to move. It can retard or stop a body which is moving. It can change the direction of motion.
Foot Pound The unit for measuring work is the ft pound or the Joule.
Friction Friction is a force which can stop or retard the motion of a moving object. Assume that one surface of a clean, dry steel block is at rest on a similar surface. Any attempt to slide the block across the contacting surface would be resisted by a frictional force. Friction occurs because of surface roughness and welding of minute metal surfaces.
Friction Resistance Friction resistance is always present between the contacting surfaces of two objects when they are moving across one another.
Hydraulic Terms EF