NOT YET RELEASED 37210-00 MechanicalSystems SG ED2 PR2 - … · Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define fluid as it

Student Guide/Portfolio

Mechanical Systems

37210-00 Edition 2

Level two

|3037210000705'~

SECOND EDITION

Second Printing, May 2007

Copyright 2005 Lab-Volt Systems, Inc.

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Mechanical Systems Table of Contents

i

Table of Contents Introduction ................................................................................................................... 1 Topic 1 – Pneumatics–Energy Transmission ............................................................... 3

Activity 1 – Pneumatic Trainer Safety...................................................................... 3 Activity 2 – Properties of Gases................................................................................. 4

Data Sheet – Cylinder Force Table........................................................................ 5 Data Sheet – Full Area (AF) Calculation ............................................................... 6 Data Sheet – Annular Area (AA) Calculation ........................................................ 7 Data Sheet – Ratio of Applied Pressures............................................................... 8 Data Sheet – Pressure and Volume Relationship ............................................... 10 Data Sheet – Final and Initial Volumes.............................................................. 11

Topic 2 – Pneumatics–Energy Control ....................................................................... 13 Activity 1 – Control of Pressure and Vacuum......................................................... 13

Data Sheet – Control of Pressure and Vacuum................................................... 14 Activity 2 – Flow Rate and Directional Control...................................................... 15

Data Sheet – Flow Rate and Directional Control................................................ 16 Topic 3 – Pneumatics–Control Circuits ...................................................................... 17

Rubric .................................................................................................................... 17 Activity 1 – Reviewing Component Descriptions.................................................... 18 Activity 2 – Reading Schematic Diagrams.............................................................. 19

Data Sheet – Reading Schematic Diagrams........................................................ 20 Activity 3 – Create Meter-In and Meter-Out Circuits............................................ 23

Data Sheet – Meter-Out Circuits......................................................................... 24 Data Sheet – Meter-Out Circuit of Your Own Design ........................................ 26 Data Sheet – Meter-In Circuit of Your Own Design ........................................... 27

Topic 4 – Hydraulics–Fundamentals .......................................................................... 29 Activity 1 – Calculate Area, Force, and Pressure................................................... 29

Data Sheet – Calculating and Measuring Force ................................................. 30 Activity 2 – Volume, Capacity, and Fluid Flow ...................................................... 31

Data Sheet – Calculating Piston Extension Rate ............................................... 32 Topic 5 – Hydraulics–System Details ......................................................................... 33

Rubric .................................................................................................................... 33 Activity 1 – System Maintenance............................................................................ 35

Data Sheet – Hydraulic Trainer Start-Up Observations.................................... 36 Activity 2 – Advanced Components......................................................................... 37

Data Sheet – Simulation of Hydraulic Blade Cylinders on a Snowplow............ 38

Mechanical Systems Table of Contents

ii

Activity 3 – Reduced Pressure Circuits................................................................... 39 Data Sheet – Testing the Operation of a Pressure Reducing Valve................... 40

Activity 4 – Operating Advanced Circuits .............................................................. 42 Data Sheet – Operating a Series Circuit, Part 1................................................. 43 Data Sheet – Operating a Series Circuit, Part 2................................................. 44 Data Sheet – Operating a Parallel Circuit, Part 1.............................................. 45 Data Sheet – Operating a Parallel Circuit, Part 2.............................................. 46

Topic 6 – HVAC ........................................................................................................... 47 Activity 1 – Heat Value Concepts............................................................................ 47

Data Sheet – Heat Energy and Temperature...................................................... 48 Data Sheet – Heat Transfer ................................................................................. 49

Activity 2 – Fundamentals of Airflow ..................................................................... 50 Data Sheet – Working with Pressure Measurements......................................... 51

Activity 3 – Refrigeration ........................................................................................ 52 Data Sheet – "Cold" Metal vs. "Warm" Book....................................................... 53

Activity 4 – Residential Air Conditioning ............................................................... 54

Mechanical Systems Introduction

1

Introduction

This Student Guide/Portfolio serves as a record of your progress through the multimedia presentation and CELL Guide activities. It includes data sheets and assessment forms. It is structured in the same way as the CELL Guide and the multimedia presentation. Each CELL is divided into topics and each topic consists of a series of activities. Either the multimedia presentation or the CELL Guide will direct you to the Student Guide/Portfolio. You will use the forms available to record your observations, track data, or summarize your experience. Your instructor completes the assessment forms where your performance is observed. Both the data sheets and the assessment forms are labeled according to the topics and activities to which they relate and appear in the corresponding places in your Student Guide/Portfolio. Ask your instructor about adding any additional materials to this guide that you complete during the topics. By keeping a record of your forms and collecting your own work, you create a portfolio that documents your progress through the topics and reviews what you have learned in applying the various technologies.

Mechanical Systems Introduction

2

Mechanical Systems Topic 1 – Pneumatics–Energy Transmission

3

Topic 1 – Pneumatics–Energy Transmission

Activity 1 – Pneumatic Trainer Safety Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. What is the purpose of OSHA (Occupational Safety and Health Administration)? List at least 5 safety procedures pertaining to the Lab-Volt 6081 Pneumatics–1 Trainer.


4

Activity 2 – Properties of Gases Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define fluid as it is used in the following sentence: In a fluid power system, fluid will flow from an area with high pressure to an area that has less pressure. Write a brief explanation of Pascal’s law. Write a brief explanation of Boyle’s law. Write a brief explanation of Charles’ law.


5

Data Sheet – Cylinder Force Table Name Date

Cylinder Force Table Use the formula F = PA to calculate the cylinder force and enter your answers in the Calculated Cylinder Force column of the Cylinder Force Table.

CYLINDER FORCE TABLE Applied Pressure

on Full Piston Area Calculated Cylinder

Force

Measured Cylinder

Force 40 psi (276 kPa)

lbf (N)

lbf (N)

20 psi (138 kPa)

lbf (N)

lbf (N)

On the spring-load device, observe the lbf (pounds force) or Newtons scale and record the values in the Measured Cylinder Force column. Look at the values you entered in the table. Are the calculated and measured cylinder forces within 20 percent of each other? Yes ____ No____

NOTE: A 20-percent margin of error is allowable due to a combination of system leakage and gauge tolerances.


6

Data Sheet – Full Area (AF) Calculation Name Date

Use the formula below to calculate the full piston area (AF). The diameter of cylinder (D cylinder) is 1.06 in (2.7 cm). π x D2cylinder AF = ____________________

4 The calculated full area (AF) of the piston is _______in2(cm2).


7

Data Sheet – Annular Area (AA) Calculation Name Date

The annular area (AA) of the piston is the full piston area (AF) minus the rod area. To find the rod area multiply π times the diameter of the rod squared. The diameter of the rod (Drod,) is 0.31 in (0.8 cm). Use the following formula to calculate the annular area of the piston (round off your calculations to two decimal places): π x D2rod AA = AF – ____________ = ________ 4 Now that you've calculated the annular area and the full piston area, what is the ratio between the two areas? Area Ratio: AA _____ = ________ AF


8

Data Sheet – Ratio of Applied Pressures Name Date You applied 50 psi (345 kPa) to the full piston area in Topic 1, Activity 2, step 19. Enter this value as PF in the table on this page. You measured pressure from the rod end of the cylinder in topic 1, activity 2 step 20. This pressure is the applied pressure on the annular area of the piston. Enter this value as PA in the table on this page

PRESSURE APPLIED TO THE FULL PISTON AREA

PF =

PRESSURE APPLIED TO THE ANNULAR PISTON AREA

PA=

What is the ratio of the applied pressure on the full piston area to the applied pressure on the annular area? Pressure Ratio: PF _____ = __________ PA


9

Data Sheet – Ratio of Applied Pressures Name Date Now compare the area ratio with the pressure ratio: Area Ratio: AA _____ = ________ AF Pressure Ratio: PF _____ = __________ PA The area ratio should be approximately equal to the reciprocal of the pressure ratio. Do your results confirm that F = PA x AA = PF x AF? Yes________ This result confirms Pascal’s law. No_________ Recheck your measured values. Verify that you used a short piece of tubing to connect the components.

F = PA x AA = PF x AF


10

Data Sheet – Pressure and Volume Relationship Name Date As you connect a pressure gauge to the rod end of the cylinder using a short length of tubing, the gauge reading should be 0. Add the atmospheric pressure (14.7 psi or 101.3 kPa) to the gauge reading; this is the initial absolute pressure. Record this value as (P1).

Observe the gauge pressure when the piston is extended to the halfway mark and add the atmospheric pressure (14.7 psi or 101.3 kPa) to the gauge pressure. This is the final absolute pressure. Record this value as (P2).

INITIAL ABSOLUTE PRESSURE

P1 = FINAL ABSOLUTE

PRESSURE P2 =


11

Data Sheet – Final and Initial Volumes Name Date The final volume (V2) is half the initial volume (V1) when the rod is extended halfway. Therefore, V2 is 1 in3 since V1 is 2 in3 (theoretically).

FINAL VOLUME

V2 = 0.5 x V1

V2 = ______ in3(cm3)

INITIAL VOLUME

V1 = 2 x V2

V1 = ______ in3(cm3)

Final Absolute Pressure Calculation Using the formula for Boyle's law, calculate the final absolute pressure. The formula for Boyle's law is P1/ P2 = V2/V1. To isolate P2, the formula can be rearranged as follows:

P1 x V1 P2 = ______________ =

V2


12

Mechanical Systems Topic 2 – Pneumatics–Energy Control

13

Topic 2 – Pneumatics–Energy Control

Activity 1 – Control of Pressure and Vacuum Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define gauge pressure. Define absolute pressure. Define vacuum. List at least two applications where pneumatic systems rely on vacuum pressure.


14

Data Sheet – Control of Pressure and Vacuum Name Date

WATER COLUMN HEIGHT PRESSURE READING

ONE-THIRD HEIGHT psi (kPa)

TWO-THIRDS HEIGHT psi (kPa)

FULL HEIGHT psi (kPa) What does the height of the water column represent? What do the pressure readings indicate?


15

Activity 2 – Flow Rate and Directional Control Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Explain the measurement standard for a cubic foot (ft3) and standard cubic meter (scm) of air. What is the purpose of a flowmeter in a pneumatic system? What are air bearings designed to accomplish?


16

Data Sheet – Flow Rate and Directional Control Name Date

FLOW RATE MEASUREMENT IN LITERS PER MINUTE FLOW RATE

REGULATOR PRESSURE

FLOW CONTROL VALVE CONDITION

20 PSI (138 kPa) PARTIALLY OPEN 20 PSI (138 kPa) COMPLETELY OPEN 40 PSI (276 kPa) PARTIALLY OPEN 40 PSI (276 kPa) COMPLETELY OPEN 60 PSI (414 kPa) PARTIALLY OPEN 60 PSI (414 kPa) COMPLETELY OPEN

How did the flow rate correspond with the flow control valve adjustment and the pressure settings?

Mechanical Systems Topic 3 – Pneumatics–Control Circuits

17

Topic 3 – Pneumatics–Control Circuits

Rubric A rubric represents an opportunity for you to directly interact with your instructor to show what you have learned about this topic. Therefore, at the end of this topic you must notify your instructor and give him or her the checklist below. Given a schematic diagram, you will be asked to construct a circuit on the Pneumatics-1 trainer, take a measurement, and explain the function of the circuit. This authentic assessment activity will receive a grade and will also indicate to your instructor if you need additional practice before continuing with this CELL.

Note to instructor: Refer to the Instructor Guide for detailed scenario information.

Scenario Assessment

1 100 75 50 25 0 2 100 50 0 3 100 75 50 25 0


18

Activity 1 – Reviewing Component Descriptions Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Graphic symbols provide a simple and universally accepted way of depicting pneumatic components. What pneumatic components or functions can the following symbols represent? • Circle: • Empty triangle: • Square or box: • Arrow: • Lines (solid, dotted, double, curved, crossed): • Diamond: What is one purpose of a directional control valve in a pneumatic circuit?


19

Activity 2 – Reading Schematic Diagrams Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define schematic diagram. List at least 5 guidelines, rules or standards for drawing standard schematic symbols.


20

Data Sheet – Reading Schematic Diagrams Name Date Locate the 3-way/2-position DCV supplied with the trainer and look at the schematic symbol on its label. Draw the schematic symbol here. What information about the DCV does the schematic symbol supply? Locate the bi-directional motor supplied with the trainer and look at the schematic symbol on its label. Draw the schematic symbol here. What information about the motor does the schematic symbol supply?


21

Data Sheet – Reading Schematic Diagrams Name Date

How did the cylinder respond to the remote operation of the 5/2 DCV when the push button on the left DCV (V1) was pressed? How did the cylinder respond to the remote operation of the 5/2 DCV when the push button on the right DCV (V2) was pressed? How was system pressure applied to the cap end and the rod end of the cylinder?


22

Data Sheet – Reading Schematic Diagrams Name Date

Explain the cylinder response to the pilot pressure ports of the 5/2 DCV while the branch shutoff valve that connects to the input ports of the 5/2 DCV is closed?


23

Activity 3 – Create Meter-In and Meter-Out Circuits Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Discuss the difference between a meter-in and a meter-out circuit. What characteristics do needle valves and flow control valves have in common? Discuss the internal check valve of a flow control valve.


24

Data Sheet – Meter-Out Circuits Name Date

What conditions will produce a fast extension of the cylinder rod? What conditions will produce a slow extension of the cylinder rod? What is the function of the DCV in this circuit?


25

Data Sheet – Meter-Out Circuits Name Date If the push button on the DCV is pressed, which type of circuit is in use, and what type of cylinder response from the double-acting cylinder can be expected?

NOTE: This schematic diagram is meant for illustration purposes only. The components shown are not supplied with the 6081 Pneumatics-1 Trainer.


26

Data Sheet – Meter-Out Circuit of Your Own Design Name Date Draw the schematic of the meter-out circuit that you assembled on the pneumatics trainer. Write a paragraph, draw a pictorial diagram, or use a combination of the two to explain how your circuit functions. Include a description of how the operator can control the direction and speed of the cylinder rod.


27

Data Sheet – Meter-In Circuit of Your Own Design Name Date Draw the schematic of the meter-in circuit that you assembled on the pneumatics trainer. Write a paragraph, draw a pictorial diagram, or use a combination of the two to explain how the circuit functions. Include a description of how the operator can control the direction and speed of the cylinder rod.


28

Mechanical Systems Topic 4 – Hydraulics–Fundamentals

29

Topic 4 – Hydraulics–Fundamentals

Activity 1 – Calculate Area, Force, and Pressure Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. List at least 6 hydraulic trainer safety procedures. Discuss the formula F = PA.


30

Data Sheet – Calculating and Measuring Force Name Date

Pressure Calculated Force Measured Force

500 psi (34.5 bar)

400 psi

(27.6 bar)

300 psi

(20.1 bar)


31

Activity 2 – Volume, Capacity, and Fluid Flow Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Discuss the formula V = AH. Define volume. Define capacity.


32

Data Sheet – Calculating Piston Extension Rate Name Date

FLOW RATE TO CYLINDER

CALCULATED EXTENSION

TIME

ACTUAL EXTENSION

TIME

GAUGE "A"

GAUGE "B"

2.0 lpm/0.52 gpm

2.5 lpm/0.66 gpm

3.0 lpm/0.79 gpm

Mechanical Systems Topic 5 – Hydraulics–System Details

33

Topic 5 – Hydraulics–System Details

Rubric A rubric represents an opportunity for you to directly interact with your instructor to show what you have learned about this topic. Therefore, at the end of this topic you must notify your instructor and give him or her the checklist below. Given a hydraulic system schematic diagram, you will be asked to identify the components of the circuit, describe the type of circuit, and explain its function. This authentic assessment activity will receive a grade and will also indicate to your instructor if you need additional practice before continuing with this CELL.

Note to instructor: Refer to the Instructor Guide for detailed scenario information.

Scenario Assessment

1 100 75 50 25 0 2 100 0 3 100 75 50 25 0


34


35

Activity 1 – System Maintenance Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Discuss preventive maintenance. Discuss the primary purpose of a hydraulic system. List three types of petroleum-based hydraulic fluids. List three basic types of fire-resistant hydraulic fluid.


36

Data Sheet – Hydraulic Trainer Start-Up Observations Name Date

Initial Oil Temperature

Initial System Pressure

5 Minute Oil Temperature

5 Minute System Pressure

Pressure when Flow Rate Drops

Pressure when Flow Control Valve Closes

Gauge 1 Pressure

550 psi (37.92 bar)

Gauge 2 Pressure


37

Activity 2 – Advanced Components Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define hydraulic pump. List three types of hydraulic pumps. List at least three common applications of hydraulic accumulators. Discuss the function of a hydraulic reservoir.


38

Data Sheet – Simulation of Hydraulic Blade Cylinders on a Snowplow Name Date Which component from the simulated snowplow circuit unloads the pump when pump output isn’t being used? What is the pressure reading on the pressure gauge when you simulate a stalled cylinder? Which component in this circuit do you think prevents pressure from rising above this reading when the cylinder stalls?

During normal operation, a snowplow does not use pump output during snowplowing because the blade drops and rests on the surface of the street.

Mechanical Systems Topic 6 – HVAC

39

Activity 3 – Reduced Pressure Circuits Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Discuss pressure reducing valves and include at least two facts or applications in the discussion. List at least 3 tasks that a “clamp-and-work” circuit can perform. Discuss the use of different sized cylinders in the “clamp-and-work” circuit that you constructed on the hydraulic trainer.


40

Data Sheet – Testing the Operation of a Pressure Reducing Valve Name Date When you increased the circuit pressure by slowly turning the adjustment knob on the relief valve clockwise until gauge "A" reads 500 psi (34.5 bar), what was the pressure level downstream from the reducing valve? When you decreased the load (pressure demand) downstream from the reducing valve by turning the adjustment knob on the flow control valve one turn counterclockwise, what was the pressure reading downstream from the reducing valve? What happens to the oil flow rate and to the pressure level downstream from the reducing valve as the pressure demand is decreased?


41

Data Sheet – Testing the Operation of a Pressure Reducing Valve Name Date What happens to the oil flow rate and to the pressure level downstream from the reducing valve as the pressure demand is increased? According to the pressure reading on gauge "B", is the pressure level downstream from the reducing valve still limited to the 200-psi (13.8 bar) setting of this valve? Did the downstream pressure decrease when the reducing valve is completely closed? Explain your answer.


42

Activity 4 – Operating Advanced Circuits Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Describe the physical connection of two cylinders connected in parallel. Describe the physical connection of two cylinders connected in series. Define mechanical yoke.


43

Data Sheet – Operating a Series Circuit, Part 1 Name Date In step 10 of operating a series circuit, part 1, do the rods start and stop extending at the same time? In step 10 of this activity, does the rod in the downstream cylinder completely extend?

PRESSURE READINGS LOAD CONDITION

GAUGE "A" (UPSTREAM CYLINDER)

GAUGE "B" (DOWNSTREAM

CYLINDER)

NO LOAD

MEDIUM LOAD

HEAVY LOAD

STALL


44

Data Sheet – Operating a Series Circuit, Part 2 Name Date In step 4 of operating a series circuit, part 2 do the cylinder rods start and stop extending at the same time? Explain your results.

PRESSURE READINGS LOAD CONDITION

GAUGE "A" (UPSTREAM CYLINDER)

GAUGE "B" (DOWNSTREAM

CYLINDER) NO LOAD

MEDIUM LOAD

HEAVY LOAD

STALL


45

Data Sheet – Operating a Parallel Circuit, Part 1 Name Date In step 9 of operating a parallel circuit, part 1, which cylinder rod extends first, and why?


46

Data Sheet – Operating a Parallel Circuit, Part 2 Name Date In step 2 of operating a parallel circuit, part 2, the flow control valve simulates a heavy load on the cylinder when it is open one-half turn. Which cylinder do you think will extend first? In step 9 of this activity, do the cylinders remain synchronized now that you've changed the setting of the flow control valve? In step 6 of this activity, the flow control valve simulates a heavy load on the cylinder when it is open one-half turn. Which cylinder do you think will extend first? In step 11 of this activity, do the cylinders remain synchronized after 15 minutes of circuit operation? In step 12 of this activity, are you able to control the extension sequence of the cylinder rods? Explain why or why not.


47

Topic 6 – HVAC

Activity 1 – Heat Value Concepts Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. What does a British thermal unit represent? What is temperature? What is kinetic energy? List three common scales used to measure temperature.


48

Data Sheet – Heat Energy and Temperature Name Date Considering that a gallon of water weighs 8.3 lb (3.77 kg), and considering that Btu = lb x ∆T (and Cal = g x ΔT), how many British thermal units (or Cal) does it take to raise the temperature of 55 gal of water from 60º F (15.56ºC) to 70º F (21.11ºC)? How many calories would 75 g of water release if it cooled from 80º C to 50º C? Show your work. Use the equation for calculating Btu (Btu = lb x ∆T ºF x specific heat) or Cal (Cal = g x ΔT ºC x specific heat) to answer the following question. Considering that the specific heat of ice = 0.487, how many British thermal units (or Cal) are required to raise the temperature of 10 lb (4.54 kg) of ice from 27º F (-2.78ºC) to 30º F (-1.12ºC)?


49

Data Sheet – Heat Transfer Name Date Find the amount of heat energy (in British thermal units per hour or Watts) that a 12-ft2 (1.115 m2) triple-pane glass window with a 2.8 R-value saves over an identically sized single-pane glass window with a 0.9 R-value, when it is 10 degrees colder outside than inside. (Note; a delta of 10ºF = 5.56ºC and to find the metric equivalent of an R-value multiply by 0.176) Determine the type of building you live in, and estimate the hourly rate of air exchange by looking at the ACH chart shown here. The approximate air changes per hour in your home is:______________

Building Type Approximate Air Changes per Hour New, energy-efficient, tight construction 0.5 ACH New, ordinary construction 1.0 ACH Old, ordinary construction 1.5 ACH Old, leaky, needs-maintenance

construction 3.0 ACH


50

Activity 2 – Fundamentals of Airflow Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Discuss velocity pressure. What is total pressure? How does airflow differ in centrifugal and axial fans? Why does rectangular ductwork have the least efficient geometry for airflow?


51

Data Sheet – Working with Pressure Measurements Name Date Find the head equivalent of 0.6 psi (4.14 kPa) in inches (cm) of water. What pressure, expressed in pounds per square inch (kPa), is equal to a 7 inch (17.78 cm) column of mercury? Find the velocity pressure of air moving at 1,000 ft/min (304.8 m/min).

Head/Pressure Equivalents To find inches (cm) of water, multiply psi by 27.7 (kPa by 10.23). To find psi (kPa), multiply inches (cm) of mercury by 0.49 (1.33). To find psi (kPa), multiply inches (cm) of water by 0.0361(0.0978).

Determining Velocity pressure Velocity pressure = (speed/4,005)2, where: Velocity pressure is expressed in inches of water. Airspeed is expressed in feet per minute (ft/min). The value 4,005 is a constant. (The airspeed divided by the square root of the velocity pressure is approximately 4,005.) Metric formula = Pv (Pa) = 0.6[velocity (m/s)]2 • Velocity pressure is expressed in Pascal. • Airspeed is expressed in meters per second (m/s).


52

Activity 3 – Refrigeration Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Who is Willis Haviland Carrier? What is refrigeration? Refrigerants are usually selected based on four major criteria. List at least three of them. Define Dobson unit.


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Data Sheet – "Cold" Metal vs. "Warm" Book Name Date Record the temperature of each flat surface.

SURFACE MATERIAL SURFACE TEMPERATURE

ROOM TEMPERATURE = Determine the average of the three recorded temperatures and record this value as room temperature.

ADDITIONAL SURFACE MATERIAL

SURFACE TEMPERATURE

Arrange the list in the order of how cold the materials felt (from coldest to warmest).


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Activity 4 – Residential Air Conditioning Name Date

Key Concepts Write a definition, explanation, or list of steps for each of the following Key Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. What is a heat pump? How do geothermal heat-pump systems operate? List at least 6 sources of indoor air pollution.

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NOT YET RELEASED 37210-00 MechanicalSystems SG ED2 PR2 - … · Concepts. These notes will serve as a study guide for the quizzes, topic tests, and the posttest. Define fluid as it