Hydraulics Final Exam
Direct
Heavy internal springs are used to establish the operating pressure of the ____-operating type of pressure control valves.
Series
If hydraulic motors are connected in ____, all of them operate at the same time, as long as the total pressure requirement is below the setting of the system relief valve.
Power output shaft
In the inline piston motor design, the centerline of the pistons and cylinders is inline with the centerline if the ____.
Swash plate
In the inline piston motor, a(n) ____ is used to change the linear movement of the pistons to rotary motions of the power output shaft.
20
It is typically recommended that the average fluid velocity in a hydraulic system working line should not exceed ____ per second.
One-piece; Tie rod; Threaded end; Mill
List the four basic construction types of cylinders.
Fixed centerline; Fixed non-centerline; Pivoting centerline
List the three basic configurations used to mount cylinders to equipment.
Mechanical pressure; Pilot pressure; Electromagnets
List the three sources of external force that can be used to position control valve elements.
Both pump and motor have fixed displacement; pump has fixed and motor is variable; Both pump and motor are variable displacement
List three possible pump/motor arrangements that may be used with a hydrostatic system.
Overall efficiency; Varying type and sizes of conductors; Cost; Installation drawings
Name some categories of data typically found in information sheets provided by pump manufacturers.
Provide energy to an operating system; maintain proper system operating pressures; energy displacement
Name some functions of a hydraulic system power unit.
Gear; Vane; Piston
Name the three most common, basic designs of hydraulic motors.
Operations; Construction type
Name the two common ways in which cylinders are classified.
Clevis; Trunnion
Name the two pivoting-centerline cylinder-mounting methods that allow the cylinder to follow the arc made by a pivoting machine member.
Safety valve; Hydraulic fuse
Name the two types of pressure control valves that are used to prevent damage to hydraulic systems in cases where the system relief valve fails, causing excessive system pressure.
Housing; Input/Output ports; Cap/Head
Name three basic components that make up a hydraulic cylinder.
Open and close valves; Control valve positions to determine flow
Name two basic uses of springs in the operation of hydraulic control valves.
Can act like a pump causing cavitation; Shock pressure builds up
Name two conditions that can exist when stopping a hydraulic motor, if the circuit has not been properly designed.
Flexibility; Chemical resistance; Cost
Name two factors that are important to consider when selecting hose for and installation.
Inefficient operations; High cost of maintenance; Difficult assembly
Name two situations that may result if conductors and fitting are not carefully selected for a given hydraulic system.
25
Safety valves are typically set at a pressure ____% above the setting of the primary system relief valve.
False
T or F? Low- and high-pressure hoses may be clamped together, although this is not an ideal configuration.
Center
The middle position in a three-position, four-way directional control valve is often called the ____ position. It provides a control feature beyond cylinder extension and retraction.
Laminar
The opposite of turbulent fluid flow in a pipe is called ____ flow.
Georotor
The specialized gear design that is used with most internal gear motors is called a(n) ____.
Sayborn
The system that indicates hydraulic fluid viscosity by the time it takes 60 mL of the fluid to flow through a calibrated orifice is called the ____ universal viscosity system.
Housing, rotating internal parts, and power output shaft
The three conceptual component groups that make up any hydraulic motor are ____.
Conduction, convection, radiation
The three modes of heat transfer are ____, ____, and ____.
Wipers keep out contaminants; Standard seal is used to prevent fluid leakage.
Two types of sealing components are used to seal the area around the rod of a cylinder.
Self-actuation; Mechanical; Pilot pressure; Manual actuation
What are four general categories of actuation methods used to shift directional control valves?
Shut-off; Check; Three-way; Four-way
What are the four general classifications of directional control valves used in a hydraulic system?
Bypass; Restrictor
What are the two general operating designs of flow control valves?
Springs; Pilot pressure
What are the two sources of internal force typically used to position control valve elements?
2-position
Which type of four-way valve allows cylinder extension in one position and cylinder retraction in the second position?
Springs
____ are often used on the ends of the spool in directional control valves to automatically return the valve to the normal or restart position whenever the activation force is removed.
Replenishment
____ circuits are used in closed-loop hydraulic systems to make up fluid lost from leakage during system operation.
Three-way
____ directional control valves are designed for the actuation of rams and single-acting cylinders.
Needle
____ valves are used in hydraulic systems as both shut-off and metering devices.
Ball
____ valves may be adjusted from the fully open position to the fully closed position by turning the control handle only 90 degrees (1/4 turn).
Tie rod
A cylinder that had externally mounted metal rods holding the ends on the barrel is called a(n) ____ cylinder.
Swaging
A hydraulic fitting can be attached by threads, cramping, or ____ like was demonstrated in the industrial maintenance lab.
Unbalanced
A motor in which the output shaft bearings are side located is classified as a(n) ____ design.
Externally
A pressure-reducing valve is normally open and must be ____ drained.
A cylinder
A primary component represented by a rectangle is ____.
Ram/cylinder inlet and outlet; Reservoir inlet; Pump discharge
A three-way directional control valve has the reports. Name what each port is connected to in the system.
Cylinder
A(n) ____ is the system component that converts fluid pressure and flow into linear force and movement.
Universal joint
A(n) ____ is used to connect the cylinder barrel and the power output shaft of a bent-axis hydraulic motor.
Dryseal
A(n) ____ standard pipe thread should be used when assembling pipe to prevent leakage when the joint is placed under high system pressure.
Plunger
An unloading relief valve uses a(n) ____ mechanism to assist in the operation of the balancing piston in the pilot section of the valve.
Torque
As the displacement is reduced in a variable-displacement came motor, the speed of the motor increases, while the potential ____ output decreases.
Equipment drive wheels
Can-type radial-piston motors are often used in construction equipment applications where ____ are directly mounted on the power output shaft of the motor.
Motion; Force
Control valves allow a hydraulic system to produce the type of ____ and ____ level of ____ needed for machine operation.
Speed
Controlling the flow rate of fluid entering and actuator controls the ____ of that actuator.
Restrained
Counterbalance and brake valves provide ____ control in hydraulic systems.
Operating surface area
Cylinder rod extension speed may be calculated by multiplying the flow rate going into the actuator by 232 and then dividing by the ____.
Tension
Decreasing surface ____ allows anti-foaming agents to reduce the formation of bubbles and foam in a hydraulic system reservoir.
Valve that contains a disc that ruptures when system pressure above predetermined setting is breached.
Describe a hydraulic pressure fuse.
Straight threads for O-rings; Pipe threads for attachments and fittings
Describe two general methods used for securing an adapter fitting when attaching hydraulic conductors to fittings and major system components.
Kinetic
Energy in motion is known as ____ energy.
Do work
Energy is defined as the capacity to ____.
Heat
Energy that is lost because of high flow resistance produces ____, which can cause system operating problems.
Turbulent
Excessive fluid velocity in a working line may produce ____ flow, which can result in reduced system efficiency.
Orbiting
The ____ georotor design of an internal gear motor uses a fixed gear with internal teeth and a rotating valve plate instead of crescent-shaped inlet and outlet ports.
Needle
The ____ is the simplest of the adjustable, noncompensated flow control valves.
Pilot
The ____ method of directional control activation uses system pressure, which may be remotely sensed, to shift the valve.
Valve body
The ____ serves as the holder of all working elements of the valve.
Bearing shaft
The balanced-vane motor configuration places a balanced load on the ____ of the motor.
psi
The common unit designation of pressure in fluid power systems in the U.S. is ____.
Parallel
A circuit that provides an individual route for the current to follow through each load is called a(n) ____ circuit.
Cylinder
A hydraulic ____ is an actuator that converts energy stored in the system fluid into linear motion.
1st class
A lever in which the fulcrum is located between the effort and load arms is called a(n) ____.
Combustion
A primary disadvantage of petroleum-based hydraulic fluids is low resistance to ____ which makes them unsuitable in many applications.
Manifold
A(n) ____ is a machine or fabricated element that provides a common hydraulic fluid supply to several system components.
Vent
A(n) ____ is used on reservoirs to allow the tank to take in or release air as the fluid level changes during system operation.
Reciprocating
A(n) ____ pump design uses the up-and-down linear motion of a piston in a cylinder to move fluid through the unit.
Bypass
A(n) ____ valve is used in the design of fluid power system filters to route fluid around the filter element of it becomes clogged during system operation.
Pressurized
All fluid power systems should always be treated as if they are ____ and ready to function.
Temperature, humidity
Appropriate air exchange and circulation in a work environment are important for the maintenance of suitable ____ and ____ levels.
Wedge, Screw
Examine the descriptions below and identify them with the basic machine. A: Two inclined planes fastened together ____. B: A spiral inclined plane ____.
Inlet/return valves below fluid surface levels in reservoir; Components in contact with outside environment; Internal leaks
Excessive air entrainment and foaming may be caused by a variety of hydraulic system design flaws or operational problems. Name some typical factors that can cause these problems.
Vibration
Flexible hydraulic hose is desirable in systems involving movable members or where severe ____ is a problem.
Return lines
Fluid power system filters may be located in one or more of three typical locations. List one of the three locations.
Pressurized
Fluid power systems use ____ fluid to transmit power.
Pressure
Force exerted over a unit area is known as ____.
Closed, Open
Hydraulics is a ____ system, where a Pneumatics is a ____ system.
Reservoir
Improving surface tension characteristics increases the rate at which water separates from hydraulic oils and collects in the ____.
Conductors
In a basic Hydraulic system, the ____ distribute fluid to components.
Flow control valve
In a basic hydraulic system, actuator extension speed is controlled by placing a(n) ____ I'm the line between the directional control valve and the actuator.
Impeller
In a centrifugal pump, the primary element of the pumping mechanism is called a(n) ____.
Adjustable
In a simplified symbol for a flow control valve, an arrow that passes through the orifice in the symbol indicates the valve is ____.
Three
In general, the reservoir for a stationary industrial system should have a storage capacity ____ times the flow rate of the pump.
Atmosphere
In the pneumatic fluid power system, after the pressurized system air has completed its work, it is exhausted to the ____.
Empirical Knowledge
It is generally believed by historians that much of the early development of fluid power was based on ____, rather than on an understanding of scientific principles.
Employee
It is the responsibility of the ____ to learn and follow the safety procedures needed to perform a job safely.
Viscosometer
Kinematic viscosity is measured with the aid of a device called a(n) ____.
Cost; Overall efficiency; Delivery characteristics
List factors that must be considered when selecting a pump for use in a hydraulic system.
Poor lubricant; Promotes rust; Freezes; Evaporates
List some characteristics of water that make it a poor hydraulic fluid should it be used alone in a fluid power system.
Cylinder with cap on one end with a piston inside; input line; output line; control valve
List some primary parts of a basic pump.
Roughness of surfaces, force moving the surfaces
List the two primary factors that determine the amount of friction between two surfaces.
Mechanical, muscular, electrical
List three of the five classifications of control mechanisms for which symbols are available.
Lack of hazard awareness, fear of operating a machine, impatience
List three personal factors that can cause an individual worker to perform a job unsafely.
Prevention of contamination; Decreased maintenance costs
List two reasons it is important to properly handle and maintain hydraulic fluids.
Poor lighting, poor ventilation, loud noise
Name environmental conditions from a shop setting that can cause cumulative injuries.
Condensation, vents allow some moisture when in contact with outside environment
Name two common ways that water can enter a fluid power system and contaminate the system fluid.
Copper or other catalysts in the components from manufacturing, oxygen becomes integrated through contamination, reacting with any water that may be in the fluid.
Name two conditions in a fluid power system that promote oxidation and general deterioration of a hydraulic fluid.
Extreme pressure test; Pump loading
Name two general methods that are used to establish the lubrication and wear prevention qualities of hydraulic fluids.
Power consumption, high pressure drops between components
Name two major problems that may appear if a fluid with too high of a viscosity is used in a hydraulic system.
Internal leakage, increased internal wear
Name two major problems that may appear if a fluid with too low of a viscosity is used in a hydraulic system.
Water in fluid promotes rust; Rate of maintenance increases
Name two problems that are commonly associated with the use of fire-resistant fluids in hydraulic systems.
Absolute
Standard atmospheric pressure registers as 0 psi on a gauge calibrated on the ____ pressure scale.
Neutral
Symbols are shown in the ____ position, unless they are part of a circuit diagram showing a sequence of operation.
Heating/cooling
Systems that cannot maintain appropriate fluid temperatures using ambient air temperatures and appropriate reservoir, pump, control valve, and actuator designs employ specialized ____ devices to control temperature.
Lubricator
The ____ adds a fine mist of oil to a pneumatic system to assure lubrication of system components.
Pneumatic
The ____ fluid power system can usually provide the best solution where lightweight and easily handled tools are a requirement.
Hydraulic
The ____ fluid power system is usually selected when an application requires a high operating pressure.
Reservoir
The ____ holds the system fluid not currently in use in the lines, pump, actuators and control components.
Piston
The ____ pump is the oldest of the pump designs used in current hydraulic system circuits.
Unbalanced
The ____ vane pump achieves a pumping action because the centers of the pump rotor and the cam run are off center.
Regulator
The basic pressure control device that sets maximum operating pressure in a pneumatic system is called a(n) _____.
Filtration
The cleanliness of the fluid in most hydraulic systems is assured by the addition of specialized ____ devices
Direct
The electrical current that involves electron flow in one direction only is known as ____ current.
Potential
The energy stored in a form that allows it to be easily released and used is known as ____.
Visual
The first step in testing a hydraulic fluid is to compare a sample taken from the reservoir with a sample of unused fluid of the same type and grade using a ____ inspection.
Heat
The fluid maintenance group removes dirt, moisture, and excessive ____.
Absolute
The force per unit of area required to move one molecular layer of a substance over another layer of the material is called ____ viscosity.
Film
The friction between two surfaces can easily be reduced by placing a layer of oil based liquid, called a ____, between them.
Latent
The heat required to produce a change of state in a substance, such as changing from a liquid to a solid, is known as ____ heat.
High-pressure
The hydraulic fluid additives that are used to prevent metal-to-metal contact in system components are called anti-wear or ____ agents.
Radial
The hydraulic pump that is usually considered to have the highest continuous pressure capability uses the ____-piston design.
Swash
The individual piston volumes in the inline axial-piston pump are determined by their position on an angular device called a(n) ____ plate.
Earplugs
The most popular hearing-protection devices are ____, which are both inexpensive and inconspicuous to wear.
Graphic
The most standardized graphic symbol type is the ____ symbol.
NFPA
The nonprofit trade association that concentrates its efforts in the fluid power products manufacturing area and limits its memberships to companies is the ____.
Transfer, Transmit
The physical components in a fluid power system are used to generate, ____, and ____ power to produce the desired results in an application.
Conditioning, Maintenance
The pneumatic fluid power system is generally considered to be the most expensive to operate because of the cost of ____ and ____.
Vapor
The pressure at which a fluid begins to vaporize is known as ____ pressure.
ANSI
The primary coordinating work with standardizing groups in the U.S. is done by the ____.
ISO
The principle coordinating group that works with standards on the international level is the ____.
Oitsode
The size of hydraulic system tuning is indicated by the actual ____ diameter of the tube.
110, 140
The temperature of the fluid in the reservoir of an operating fluid power system is ideally between ____ and ____ degrees Fahrenheit.
Celsius
The temperature scale that is commonly used in the world outside of the U.S. is the ____ scale.
Inertia
The tendency of a body to remain in motion once it has achieved operating speed is known as ____.
Electron, proton, neutron
The three parts of the atom are the ____, ____, and ____.
Electric motor; internal combustion engine
The two most common prime movers used in a hydraulic system are a(n) ____ and a(n) ____.
Hydraulic, Pneumatic
The type of fluid used in a system and fluid direction are indicated by a small equilateral triangle. A solid triangle represents a(n) ____ operation and an open triangle indicates a(n) ____ operation.
Watt
The unit of electrical power is the ____, which is equal to the work produced by a current flow of one ampere at a pressure of one volt.
Higher
Typically, the initial viscosity of a water-in-oil emulsion is ____ than what is recommended by system manufacturers.
Unsafe acts
Unsafe working conditions are often incorrectly identified as the chief cause of industrial accidents. What really is the chief cause of accidents?
Reduced surface tension; lowered ambient air temperatures around reservoir
What are two fundamental areas of system design and operation that must be analyzed to determine the cause of higher than desired system reservoir temperatures?
Occupational Safety and Health Administration
What does OSHA stand for?
Separates particles in the reservoir by maximizing the fluid travel path from intake to output; prevents sloshing and bubbles.
What is the purpose of baffles?
Overhead; L-shaped
What reservoir configuration is suitable for use with a pump that requires a positive pressure on the inlet line?
Hydraulic
What type of fluid power system is used when a high degree of accuracy is needed?
Boots; Cup seals
When cylinders are exposed to extreme conditions, contamination of system fluid can be reduced by using ____ or ____ to prevent the entry of dirt from the surfaces of the piston rods.
Polyglycol
Which fire-resistant fluid is similar to automotive antifreeze?
Heat
____ in the fluid of a hydraulic system is caused by forcing fluid through the system without completing work outside of the system.
Shock pressure
____ is a short duration, high pressure in a system that results from surges caused by control valves shifting or unexpected load changes during operation.
Standardization
____ is the preselected factors used as the basis for comparing items or procedures.
