Hydraulics and Pneumatics masterlist 1.1

A lottery pays a winner $1 million a year for 20 years. The present value of this sum at an interest rate of 8% is ? million IF the interest rate rises to 10%, then the present value of the lottery will

9.82 decrease

In air-cooled l, reciprocating compressors, the cooling air is often circulated by a fan that is an integral part of the __________.

Compressor flywheel

Provide the formula for the general gas law.

(P1 x V1)/ T1= (P2 x V2)/ T2

Name three major problems that may appear if a fluid with too low of a viscosity is used in a hydraulic system.

1. increased wear 2. increased internal leakage 3. decreased pump efficiency and control accuracy.

2 operating designs of a flow control valve.

1. restrictor 2. bypass control

List the two primary factors that determine the amount of friction between two surfaces.

1. the strength of the force 2. the type of surface involved.

Standard atmospheric pressure is _______ pounds per square inch at sea level.

14.7

If the interest rate is 9%, the present value of $200 paid one year from now equals?

183.5 * 200/ (1+.09)= 183.5

If the interest rate is 8%, the present value of $250 paid one year from now equals ? If the $250 is received in two years, the present value will equal ?

231.48 * 250/(1+.08) 214.33 * 250/(1+.o8)^2

The atmosphere blankets earth with a layer of gases approximately ______ miles deep.

360

During retraction, what is the effective area of the piston of a double- acting cylinder?

It is the area of the piston face minus the cross-sectional area of the cylinder rod.

Typically, what is the initial velocity of a water-in-oil emulsion compared to that recommended by system manufacturers?

It is usually higher than manufactures recommend initially, but tends to decrease during use close to recommended system guidelines.

The economist who coined the phrase " animal spirits" to refer to investment spending by firms was

John Maynard Keynes

A ____ check valve allows fluid flow in one direction and restricts fluid flow in the opposite direction until it receives a pressure signal through a pilot line applied to the port against the piston

a. direct-acting b.pilot-to-close c. pilot-to-open d. solenoid-actuated c. pilot-to-open

In a directional control valve schematic symbol, ____ the position boxes depict the direction of fluid flow for each spool position

a. external arrows outside b. internal arrows inside c. diagonal lines outside d. T-shaped symbols b. internal arrows inside

_____ mounting method is a method that uses tubing or threaded pipes that connect directly to a directional control valve

a. in-line b. manifold subplate c. pipe d. valve a. in-line

_____ pressure is initiated when the fluid pressure in a fluid power system shifts the spool into its desired position

a. pilot b. plc c. solenoid d. spring a. Pilot

There are _____ different subplate designs

a. two b. seven c. nine d. ten b. seven

What does an accumulator do?

absorbs and stores energy

The process that assumes all heat is retained in the air during compression is known as ________ compression.

adiabatic

Check valves are used to hold prime, avoid pump reversal, _____, and provide back pressure. (HL4 2-2)

bipass

The flow control valve is a _____ valve and a _____ valve in one body. (HL4 3-1)

check, needle

To decrease flow through a flow control valve, turn the adjuster in the _____ direction. (HL4 3-2)

clockwise

The _____ pressure is the point where the relief valve starts to open. (HL4 1-6)

cracking

The present value of lottery winnings paid over a 20 year period will ? with an increase in interest rates

decrease

When operating in a flow control circuit, the speed of the actuator _____ when the flow through the relief valve increases. (HL4 1-3)

decreases

The two types of relief valves are _____ and pilot-operated. (HL4 1-4)

direct-acting

The temperature at which a liquid gives off sufficient vapors to ignite when a flame is applied is called the____________.

flash point

A check valve is designed to provide _____ in one direction only. (HL4 2-6)

flow

The direction through a check valve that allows flow is called _____ direction. (HL4 2-3)

freeflow

3 designs of hydraulic motors

gear, vane, piston

Name the three most common, basic designs of hydraulic motors.

gear, vane, piston

Hydraulic fluids that are formulated by adding 2% to 5% soluble chemicals to water are called _____________ or ____________ fluids.

higher water content 95/5 fluids

If interest rates decrease, the present value of a fixed payment in the future will

increase

Rely on the ideas of "animal spirits" to complete the following sentence. Changes in measures of consumer confidence would be correlated to consumer spending on durable goods because people would be

irrationally confident and therefore more willing to purchase durable goods such as furniture and appliances.

The primary purpose of a relief valve is to _____ system pressure. (HL4 1-1)

limit

The check valve is a _____ way directional control valve. (HL4 2-1)

one

The most common of the synthetic fire resistant fluid is_____________.

phosphate ester.

Cylinder rod extension speed may be calculated by multiplying the flow rate going into the actuator by 231 and then dividing by______________.

piston area

Because investment spending moves in conjunction with GDP, Investment spending is

procyclical

Since investment spending rises and falls with GDP, it is

procyclical

List the three most common designs of limited-rotation actuators.

rack-and-pinion, vane, helical shaft

When using a needle valve to control speed, excess pump flow is directed over the _____ valve. (HL4 1-2)

relief

many firms have pension funds that have fixed dollar obligations to their retirees. For financial purposes, firms must estimate the present value of these obligations to their retirees. For financial purposes, firms must estimate the present value of these obligations to determine how much they truly owe their retirees As interest rates fall, the value of these obligations will

rise

In a ram, the __________ is basically the same diameter as the bore of the barrel.

rod

The balanced-vane motor configuration places a balanced load on the _______________ of the motor

shaft bearings

The poppet type check valve uses a _____ to hold the poppet on the seat. (HL4 2-5)

spring

Turning the adjustment knob on a relief valve changes the compression on the _____. (HL4 1-5)

spring

The three types of check valves used in hydraulic systems are the _____, _____, and _____ types. (HL4 2-4)

spring, ball, poppet

Different types of actuators

1. Linear- a term often used to indicate a hydraulic or pneumatic cylinder. It converts fluid pressure and flow into linear mechanical force and movement. 2. Rotary- A fluid power actuator used to produce torque and rotary motion.

List the characteristics of water that make it a poor hydraulic fluid should it be used alone in a fluid power system.

1. Poor lubricating qualities 2. promotes rust and corrosion 3. freezes within ambient temperature range 4. rapidly evaporates at higher system operating temperatures.

Name three common ways that water can enter a fluid power system and contaminate the system fluid.

1. condensation in the reservoir 2. water sprayed on the equipment for cleaning purposes 3. exposure to weather in exterior installations.

Name three conditions in a fluid power system that promote oxidation and general deterioration of a hydraulic fluid.

1. high temperature 2. entrainment of air 3. reactions caused by contact with different metals in the system.

Temperature compensation

A design feature of some flow control valves that adjusts the control orifice size to maintain a constant flow rate as viscosity changes due to changes in fluid temperature.

What is a pressure compensator

A mechanism that maintains a constant pressure difference between the inlet and outlet passageways.

According to the general gas law, what happens when the pressure of air is changed?

Any change in air pressure will result in either a temperature or volume change. If pressure is increased temperature will increase but volume will decrease. If pressure is decreased volume will increase but temperature will decrease. Pressure is inversely related to volume but linearly related to temperature.

Vegetable-based oils are classified as __________________ fluids because they can be broken down by organisms that normally exist in nature.

Biodegradable fluids

A(n)___________ is the system component that converts fluid pressure and flow into linear force and movement.

Cylinder

Define displacement

Displacement volume of air displaced per unit of time

A(n) _______________ cylinder can exert force during both the extension and retraction strokes.

Double acting

The three conceptual component groups that make up any hydraulic motor are:

Housing, rotating internal parts, and power output shaft

* GRAPH Use the aggregate demand and supply graph to show how in the accelerator theory of investment that future expectation of high GDP growth will cause GDP to increase in the current period Use the line drawing tool to show the impact of an increase in investment . From the graph, we can see that the higher investment leads to ? in GDP

Make new AD2 line above old AD1 line. Mark equilibrium an increase

Dynamic compressors can also be classifies as ____________ -displacement compressors

Non-positive- displacement compressor

Compressed air units may be defined as _____ or ________.

Portable unit or central air supply

The continuous rotating motion of the compression elements identifies a(n) _________ compressor design

Rotary

The simplest compressor design

Single acting reciprocating compressor

Two types of sealing components are used to seal the area around the rod of a cylinder. Describe the purpose of each.

Static seals- are materials compressed between two rigid, moving parts. Dynamic seals- function between two parts that are moving relative to each other.

Investment is a smaller component of GDP than consumption, but it is much more volatile.

True

Define lubricity

The ability of a liquid to form a strong film between two bearing surfaces and adhere to the surface of the material.

Define Barrel

The barrel is the tube portion of a cylinder.

what is pressure override?

The difference between the cracking pressure and the full-flow pressure of a valve.

Suppose the government said that they would not let the U.S price for a barrel of oil fall below $50. They could do this by raising taxes on oil if the price fell below $50 By keeping the price of oil high, firms would have an incentive to invest in energy-saving technologies

True

Define saturation

The maximum amount of water that can be held in the air for a given temperature.

Valve body

The structural element of a valve made from standard metal stock or a special casting. The body contains bores, chambers, lines, ports, and often fittings for valve mounting.

A cylinder that has externally mounted metal rods holding the ends on the barrel is called a(n) ______________ cylinder.

Tie rod

List the three basic configurations used to mount cylinders to equipment.

Tie rod, head-end flange, cap-end flange

Why do air bubbles entrained in a hydraulic fluid increase fluid oxidation?

To increase the surface area of the contact.

When the internal geometry of a hydraulic motor can be changed to vary output shaft speed, it is classified as a:

Variable-displacement motor

Where are lubricants typically introduced into a pneumatic system?

Work station at the beginning of the work circuit.

Solenoids alone are not strong enough to move a directional control valve spool when fluid flow is greater than ______ gpm

a. 20 b. 25 c. 35 d. 50 b. 25

In a directional control valve, port _____ receives fluid flow from the pump, while port ______ returns fluid flow to the reservoir

a. A; B b. B; A c. P; T d. D; T c. P; T

The air we breath and use as the source of air for pneumatic systems contains several gases. Name the gases and indicate the percentage at which they exist in the atmosphere.

a. Nitrogen 79% b. Oxygen 20% c. Others 1% (argon, carbon dioxide, ozone, and others.

A directional control valve _____ is a mechanism that is used to move the positioning spool in a directional control valve

a. actuator b. handle c. positioner d. slide a. actuator

A(n) ____ is an internal component of a directional control valve that is used to control fluid flow and to connect internal passages and ports

a. actuator b. piston c. plunger d. spool d. spool

A(n) ____ is the schematic representation of the direction in which a spool forces fluid to flow

a. actuator b. position c. valve port d. way b. position

A(n) ______ -center position directional control valve allows a hydraulic system to operate with more than one actuator and with each actuator operating independently of the others

a. closed b. float c. open d. tandem a. closed

A(n)______- center position directional control valve is used to hold the piston in a cylinder in the desired position while allowing fluid flow to be directed back to the reservoir without the need to activate a relief valve

a. closed b. float c. open d. tandem d. tandem

A hydraulic system that does not have a variable-displacement pressure-compensated pump typically uses a(n) _____- center or ____ - center position directional valve so that the hydraulic fluid can be returned to the reservoir

a. closed; float b. float; tandem c. open; closed d. open; tandem d. open; tandem

____ pressure is the amount of pressure required to slightly unseat a ball or poppet and start to allow fluid flow through a check valve

a. cracking b. operating c. pilot d. poppet a. cracking

List the four possible pump/motor arrangements that may be used with a hydraulic system

the first pump/motor arrangement: both components have fixed displacement. the second pump/motor arrangement: the pump has a fixed displacement and the displacement of the motor is variable. the third pump/motor arrangement: has a drive unit with a variable-displacement pump and a fixed-displacement motor. the fourth pump/motor arrangement: the pump and motor have variable displacements

The primary function of the liquid in a hydraulic system is to:

transmit the energy to do the work the system is designed to complete.

Proponents of solar energy point to the vast savings that come in the long run from using a free source of energy rather than paying high prices for electricity. Unfortunately, solar energy systems typically have a large up front expenses to install the system. Using the concept of present value, solar energy systems are more likely to be profitable when the interest rates are low.

true

The amount that the viscosity of a hydraulic fluid will change as the temperature of the fluid changes is indicated by a(n)_______________ number.

viscosity index

The water-in-oil type of fire-resistant fluids is often called an inverted emulsion because the ___________ is suspended in the __________________.

water oil

Spring-loaded____________ can be used on external gear motor designs to reduce gear end play and help control leakage around the sides of the gears.

wear plates

Suppose you have $500,000 to purchase an annuity. Currently the annuity payments are $35,000 per year as long as you live If interest rates increases, the annuity payments

will increase since the present value of future payments will fall as the interest rate rises