Hydraulic/Pneumatic System - Western Washington Universityphysics-astronomy-manuals.wwu.edu/Pasco...

© 2000 PASCO scientific

Instruction Manual andExperiment Guide forthe PASCO scientificModel SE-8764

012-07733AIncludesTeacher's Notes

andTypical

Experiment Results

Hydraulic/PneumaticSystem

i

Copyright Notice

The PASCO scientific 012-07733A Hydraulic/Pneumatic System Manual is copyrighted and allrights reserved. However, permission is granted tonon-profit educational institutions for reproductionof any part of the manual providing thereproductions are used only for their laboratoriesand are not sold for profit. Reproduction under anyother circumstances, without the written consent ofPASCO scientific, is prohibited.

Limited Warranty

PASCO scientific warrants the product to be freefrom defects in materials and workmanship for aperiod of one year from the date of shipment to thecustomer. PASCO will repair or replace at itsoption any part of the product which is deemed tobe defective in material or workmanship. Thewarranty does not cover damage to the productcaused by abuse or improper use. Determination ofwhether a product failure is the result of amanufacturing defect or improper use by thecustomer shall be made solely by PASCOscientific. Responsibility for the return ofequipment for warranty repair belongs to thecustomer. Equipment must be properly packed toprevent damage and shipped postage or freightprepaid. (Damage caused by improper packing ofthe equipment for return shipment will not becovered by the warranty.) Shipping costs forreturning the equipment after repair will be paid byPASCO scientific.

Copyright, Warranty, and Equipment Return

Please—Feel free to duplicate this manualsubject to the copyright restrictions below.

Equipment Return

If the product needs to be returned to PASCOscientific for any reason, notify PASCO scientificby letter, phone, or fax BEFORE returning theproduct. Upon notification, the return authorizationand shipping instructions will be promptly issued.

➤➤➤➤➤ NOTE: NO EQUIPMENT WILL BEACCEPTED FOR RETURN WITHOUT ANAUTHORIZATION FROM PASCO.

When returning equipment for repair, the units mustbe packed properly. Carriers will not acceptresponsibility for damage caused by improper packing.To be certain the unit will not be damaged inshipment, observe the following rules:

➀ The packing carton must be strong enough for the itemshipped.

➁ Make certain there are at least two inches of packingmaterial between any point on the apparatus and theinside walls of the carton.

➂ Make certain that the packing material cannot shift inthe box or become compressed, allowing theinstrument come in contact with the packing carton.

Address: PASCO scientific10101 Foothills Blvd.Roseville, CA 95747-7100

Phone: (916) 786-3800FAX: (916) 786-3292Email: [email protected]: www.pasco.comCredits

Author: Mr. Jim Housley

012-07733A Hydraulic/Pneumatic System Manual

1

Table of Contents

Section ................................................................................................................... Page

Copyright and Warranty, Equipment Return .............................................................. i

Equipment ................................................................................................................. 2

Introduction ............................................................................................................... 3

Apparatus Setup ....................................................................................................... 4

Connecting the Tubing to the Hydraulic Pump ................................................... 4

Bleeding the Hydraulic System ............................................................................ 4

Using with PASCO Pressure Sensors .................................................................. 5

Experiments:

Experiment 1: The Hydraulic Jack as a "Force Transformer" ............................ 6-9

Experiment 2: Relating Force, Pressure, and Area ......................................... 10-12

Experiment 3: Understanding Boyle's Law .................................................... 13-14

Teacher's Guide ................................................................................................. 15-17

Troubleshooting ...................................................................................................... 18

Technical Support .......................................................................... Inside Back Cover

Hydraulic/Pneumatic System Manual 012-07733A

2

Equipment

Equipment Included:• (a) 1 Jack Stand (Blue Melamine Board)• (b) 1 Plunger (piston) with Blue Melamine

Platform• (c) 1 60 cc Syringe Body (cylinder)• (d) 1 Hose assembly (include two one-way

valves, tee, and 2 quick-connect fittings)• (e) 1 Unattached tee• (f) 1 Hose with two quick-connect fittings• (g) 1 Unattached valve• (h) 1 Hose with 1 quick-connect fitting• (i) 1 Hose assembly with tee (for use with

optional pressure sensor)• (j-m) 4 Syringes (3 cc, 6cc, 12 cc, 20 cc)

The Transparent Devices SE-8764 Hydraulic/Pneu-matic Set includes a rugged stand that holds a largecylinder-and-piston syringe, four smaller syringes,tubing assemblies with valves and quick-connectfittings, and this manual.

Additonal Equipment Recommended(for experiments):• DataStudio®, version 1.5 or later• CI-6532A Absolute Pressure Sensor• ScienceWorkshop® Interface (700, 750,

500 or 300)• Computer• Stack of 4-6 Books• Plastic or Glass Beaker

(a) (b) (c)

(d)(e)

(f)

(g)

(h)

(i)

(j)

(k)

(l)

(m)


3

Introduction

The Transparent Devices Hydraulic/PneumaticSet includes a rugged stand that holds a largecylinder-and-piston syringe, four smallersyringes, tubing assemblies with valves andquick-connect fittings, and this manual. Thisset makes possible a number of teacher demon-strations and student experiements involvingfluids:• The operation of a pump• The hydraulic/pneumatic jack as a force

transformer (simple machine)• The difference in compressibility of

gases compared to liquids• Force, area, and the concept of pressure• The study of Boyle's law, using air or

other gases

Description

Safety Precautions

Please teach and expect safe behavior in yourclassroom and lab. Have students wear safetyglasses when working with liquids, glassware,or fragile equipment. Do not use the Hydraulic/Pneumatic System with corrosive gases.

Care and Use of the Apparatus

Some simple precautions will help ensure thatthis set provides years of use:

• When lifting a load, such as a stack ofbooks, center the load. Do not lift too heavya load with the piston, and do not lift theload above the 40 cc mark on the syringe.

• If lubrication of the syringes is needed, useonly glycerine or silicone oil. Do not usepetroleum-base lubricants, as this willquickly damage the seals.

• If needed, clean only with a damp rag with amild, non-abrasive cleaner. Do not immersethe blue melamine board parts in water.

• Use only light finger pressure on the quick-connect fittings. Do not overtighten.

• If the apparatus becomes lost or damaged,order a replacement part.


4

Apparatus Setup

Connecting the Tubing to the Pump

1. Connect the hose assemblies and associatedparts in the order (d)-(e)-(f)-(g)-(h), as shownon the previous page. Optional: [If installinga pressure sensor, connect part (i) betweenparts (f) and (g). Then connect the pressuresensor to the sidearm of part (i).]

Note: The quick-connect fittings onlyrequire a fraction of a turn with light fingerpressure. Do not overtighten.

2. Install the 60 cc syringe (c) in the Jack stand(a), with the graduations visible from thefront. Then rotate the syringe one-third turncounterclockwise.

3. Place the sidearm of the tee (e) up throughthe hole in the bottom of the stand (a) andonto the end of the syringe (c). Turn thesyringe one-third clockwise to connnect theto the syringe. Do not overtighten. Insert thepiston (b) into the syringe. Push it all the wayinto the syringe.

4. Install the 6 cc syringe onto the sidearm ofthe tee of part (d). Do not overtighten.

Note: If using the apparatus with air orother gases, the setup is complete. If usingthe unit with water, as a hydraulic system,or to obtain a better understanding of pumpaction, continue with the following steps forbleeding the system.

3. Describe the fluid movement during the pullstroke._______________________________________________________

4. Describe the movement during the push stroke.________________________________________________________

5. Close the valve (g) by turning the handle one-quarter turn, so that the handle is at right anglesto the tubing. Pump the small syringe 3 to 4times. Tell what happens and why.

6. Without allowing the ends of the tubing to comeout of the water, turn the main piston andcylinder assembly upside down.

1. Place the unattached ends of the tubing (d)and (h) in the bottom of a beaker or similarcontainer of water. Keep the valve open (on)with the handle in line with the tubing, asshown in Figure 1.

2. Pull out the small syringe to the limit of themeasuring graduation marks. Push it all theway in. Repeat this several times, watchingthe movement of the fluid and air bubbles.Make sure the ends of the tubing do notcome out of the water.

Bleeding the Hydraulic System andObserving the Action of the Pump

Figure 1


5

Apparatus Setup

Using the Pressure Sensors with the Hy-draulic/Pneumatic System

The PASCO CI-6532 Absolute Pressure Sensor maybe connected by first installing hose assembly (i)between parts (f) and (g). After connecting thetubing securely to the pressure sensor, push theopen end onto the sidearm of the tee of part (i).

CAUTION! Take the following precautions ifusing the Absolute Pressure Sensor when water isin the system, since the sensor may be damagedby exposure to water.• Do not loosen the connection to the pressure

sensor while the tube is connected to the hy-draulic system.

• Elevate the pressure sensor above the hydraulicsystem.

• Do not leave the pressure sensor connected tothe hydraulic system for extended periods.

7. Open the valve, push in the main piston toexpel any air, and close the valve. Returnthe main piston and cylinder assembly to itsnormal upright position. The process ofeliminating air from a hydraulic system iscalled "bleeding the system."

PRESSURE

SENSOR

0-700 kPa

(ABSOLUTE)

CI-6532A

700 kPa MAX

DRY AIR ONLY

PRESSURE PORT MATING

CONNECTOR:

PASCO PART NO. 640-021

C

The Absolute Pressure Sensor may be used tomeasure gauge pressure by subtracting that day'satmospheric pressure from the direct output of thesensor. Local atmospheric pressure may bedetermined in advance by reading the sensoroutput before it is connected to the system.DataStudio may be set to automatically subtractthis value to produce gauge pressure readings.

Gauge pressure is the quantity studied in Experi-ments 1 and 2.

CAUTION! Do not use the PASCO CI-6534Low Pressure Sensor with the Hydraulic/Pneu-matic System. It is designed to measure pressuresmuch less than generated with this apparatus andwill be damaged!!!

Pressure in fluids is commonly specified as eitherabsolute pressure or gauge pressure. Absolutepressure considers the entire pressure of the fluid.The CI-6532 Absolute Pressure Sensor measuresabsolute pressure directly.

When the tube of the sensor is not connected toanything, the sensor will output a value around100 kPa. This is typical atmospheric pressure(near sea level) and varies from day to day, aswell as with altitude. Only with the sensorconnected to an evacuated space will the sensoroutput a value near zero.

Absolute pressure is measured in Experiment 3.

Often, we only want to know how pressurediffers from atmospheric pressure. This iscalled gauge pressure.

Figure 2

• Before storing the sensor, disconnect thehose from the sensor.


6

Experiment 1: The Hydraulic Jack as a "ForceTransformer"

1. Set up and “bleed” the apparatus (as described on pages 4-5). Push the large piston all the way down.Install the 6 cc syringe as indicated in Figure 1.1. Its piston should be pulled out to the largest volumegraduation mark. The valve should be closed (handle at right angles to the tubing).

2. Make a stack of 4-6 books and find the weight in newtons. This is Forceout

. A Force Sensor, spring

Procedure -- Part 1

Theory

Machines such as levers, pulley arrangements, and hydraulicsystems can multiply an input force, to produce a greater outputforce. In this experiment, we will investigate this phenomenonwith a hydraulic jack.

The amount that the force is multiplied, FORCEin=FORCE

out, is

called the actual mechanical advantage (A.M.A.) of the system.

Such a system does not multiply input work. Ideally, the inputwork and output work will be equal. In actual practice, the outputwork will be somewhat less due to friction. The ratio WORK

out/

WORKin is called the efficiency of the system.

In the ideal case of no friction, WORKin = WORK

out

Substituting the formula for work,

Eq1: (FORCEin)

X (DISTANCEin)

= (FORCEout

) X (DISTANCEout

)

Simple algebra can transform this equation into

Eq2: (FORCEout

) = (DISTANCEin)

The left side of equation 1 is the actual mechanical advantage (AMA). The right side is called the idealmechanical advantage (IMA). In the ideal case, where friction is negligible, the IMA is the useful value.The IMA may be used as an estimate of the AMA, assuming the system has a high efficiency.

Figure 1.1

** A spring scale or balance is not needed if a Force Sensor is available.

• Hydraulic/Pneumatic System (SE-8764)• Ruler• Stack of books• Beaker of water

• Force Sensor (CI-6746 ir CI-6537)*• DataStudio®, version 1.5 or later• ScienceWorkshop® interface (700, 750, 500 or 300)*• Spring scale (SE-8718) or balance (SE-8758)**

* Optional: The Force Sensor, DataStudio, and a ScienceWorkshop interface are recommended, but not required for the experiment. Ifusing the Force Sensor, you must have DataStudio and a ScienceWorkshop interface.

Equipment Required:

(FORCEin) (DISTANCE

out)


7

scale, or balance may be used to find the weight. If a balance is used, you will need to calculate theweight.

3. Carefully balance several large books (4-6) on the platform of the large piston.

Note: Keep the position the books centered, and do not lean them in any direction. Do not exceed a loadof more than six books.

CAUTION! To prevent breakage, do not pump the piston above the 40 cubic centimeter mark at anytime during the experiment.

4. Push in the piston of the small syringe and notice the amount of force required. In words, compare theforce you used to the amount of force required to lift the books directly._____________________________________________________________________________

5. Compare the distance you moved the small piston to the distance the books were lifted. _________________________________________________________________

6. Pump the piston of the small syringe several times. Record your observations. __________________________________________________________________

7. Open the valve by turning the handle to line up with the tubing. What happens to the load of books?Why? _______________________________________________________________ ___________________________________________________________________

Procedure - Part II

Next, you will make measurements to quantify these observations. Record your measurements in Table1.2. Measure the distance the small piston moves as you move it from a starting position at the largestgraduation mark to the zero mark. Use a ruler, not the graduations on the syringe. This is Distance

in.

1. Pull out the small piston to the largest graduation mark. Measure the force required as you push inthe piston. Use a Force Sensor if available. If not, use another method, such as holding the syringevertical and piling on stackable lab weights. This result, expressed in newtons, is Force

in. Record

this measurement in Table 1.2.

Experiment 1 (Continued)

2. Open the valve to lower the load. Close the valve again.

3. Note the position of the large piston that supports the books. Pump the small piston for severalstrokes. Count the strokes, and use a ruler to measure the distance the piston moved. Alsonote the volume of fluid that entered the syringe. Divide the distance by the number of strokesto find the distance out for 1 stroke. Also divide the volume by the number of strokes to findthe volume of fluid that entered the large syringe from 1 stroke.

4. Repeat the above measurements for some or all of the other small syringes, as directed by yourinstructor.


8

Efficiency

In Table 1.2, Forcein and Distance

in are the force and distance involved in operating the small syringe.

Forceout

is the weight of the stack of books, and Distanceout

is the distance they were lifted as a result ofone stroke of the small piston. Explanations for calculating work, the actual mechanical advantage(AMA), the ideal mechanical advantage (IMA), and efficiency may be found in your textbook or inanother reference.

Forcein Distance

inForce

out IMAAMA Workin Work

outSyringe Distance

out

Table 1.2


Data and Calculations

Find the inside diameters of each syringe and the areas of circles of these diameters. Express the areas insquare meters. Do this by removing the pistons, measuring the inside diameters, and then calculating theareas. Record your results in Table 1.1

Note: A more accurate method is to measure the length of the graduated portion of the syringe, and notethe volume of that portion. A formula for the volume of a cylinder, Volume = Area x Length allowscalculation of the area. The diameter may be calculated from the area.

Table 1.1

AreaSyringe Diameter LengthVolume (m2)(cm) (cm)

Note: Remember to convert cm to meters (1 cc = cm3;100 cm = 1 m)


9


Questions

1. What are some examples of hydraulic systems being used in industry or everyday life?

2. Find the AMA, IMA, Workin, Work

out, and the efficiency for each system tried.

3. Which is larger, the AMA or the IMA? Why is this true? Under what sort of ideal conditionswould the AMA and IMA be the same amount?

4. Consider the cylinder diameter, cylinder cross sectional area, volume of fluid transferred, and theforces and distances. Which of these is the same for the small and large syringe?

5. The ratio of the two distances can be used to calculate the IMA. What other ratio of items inquestion 4 gives the IMA?

6. Is the efficiency different for different systems? If so, is there a trend?

7. There are two ways to calculate the efficiency from the preceding values in the table. What arethey?


10

Experiment 2: Relating Force, Area and Pressurein a Hydraulic System

Theory

In this experiment, you will apply force to four differentsyringe pistons, producing the same pressure each time. Theamount of pressure created will be just the amount needed tolift a stack of books on the hydraulic jack, and is the sameeach time. Each syringe piston has a different cross-sec-tional area, and requires a different force to produce therequired pressure. The constant pressure is established bythe weight of the books stacked on the platform of the largesyringe. The force, area, and pressure are related by asimple formula that may be discovered using this apparatus.

1. Set up and bleed the system as described on pages 4-5.

2. Carefully balance several large books on the platform of thelarge piston. Take care to position the books so that the donot lean in any direction.

CAUTION: To prevent breakage, do not pump the pistonabove the 40 cubic centimeter mark at any time during theexperiment.

3. If a PASCO CI-6532A Absolute Pressure Sensor is avail-able, first take a reading with the tubing open to theatmosphere. The result is the present atmosphericpressure at this location. Subtract this value from all ofthe following pressure measurements to obtain the gauge pressures.

4. Connect the sensor to the sidearm tee of part (i), which is connected between parts (f) and (g), asshown in Figure 2.2.

CAUTION: The following precautions must be taken if the Pressure Sensor is to be used whenwater is in the system, since the sensor may be damaged by exposure to water.

Procedure

Equipment Required:• 1 Hydraulic/Pneumatic System (SE-8764) • ScienceWorkshop® interface*• Absolute Pressure Sensor (CI-6532A)* • Beaker of water• DataStudio®, ver. 1.5.1 or later • Ruler• Stack of books • Force Sensor (CI-6746)* or CI-6737

Figure 2.2

* Optional: The Absolute Pressor Sensor and Force Sensor are recommended, but not required. If using either sensor,you will also need DataStudio and a ScienceWorkshop interface.

Figure 2.1

PRESSURE

SENSOR

0-700 kPa

(ABSOLUTE)

CI-6532A

700 kPa MAX

DRY AIR ONLY


CONNECTOR:


(d)

(f)

(i)

(h)

(e)

(g)

• Do not loosen the connection to the pressure sensor while the tube is connected to the hydraulicsystem. (See the next page for more necessary precautions.)


11



Find the cross-sectional area of the small syringe. This may be done by measuring the inside diameter ofthe syringe, and using the formula for the area of a circle. (Note: A more accurate method is to use a rulerto measure the graduated portion of the syringe, and to note the volume of that portion.) A formula forthe volume of a cylinder, Volume = Area x Length allows calculation of the area. The diameter may becalculated from the area. Convert the area to square meters. Record the pressure if a Pressure Sensor isavailable.

Force (N) AreaSyringe StackedWeight

(m2) Gauge Pressure(Calculated)(N/m2)

1. Make a graph displaying the (area, force) data pairs from the four small syringes.Area should be plotted along the horizontal axis, and force along the vertical axis.

2. A straight line passing through the origin should show the pattern of the data. Usesoftware such as DataStudio, or traditional techniques, to determine the slope and theequation of this best-fit line.

3. Calculate the pressure by considering the weight of the books and the area of the pistonsupporting them. Make the necessary measurements, and calculate the pressure inNewtons/square meters.

Table 2.1

Gauge Pressure(Sensor) (kPa)

5. With the smallest piston installed at point (d), measure the force required to push in the plungerand lift the stack of books. Use a CI-6746 Force Sensor if available. If not, use anothermethod such as holding the syringe vertical and piling on stackable weights.

6. Repeat the above steps for as many of the four small syringes, as time allows.

• Elevate the Pressure Sensor above the hydraulic system.• Do not leave the Pressure Sensor connected to the hydraulic system for extended periods.• Before storing the sensor, disconnect the hose from the sensor.

SENSOR PRECAUTIONS (continued)


12

3. How does the linear graph of this experiment relate to pressure?

4. PASCO's pressure sensors produce pressure readings in kPA (kilopascals). How is a pascal definedin terms of other common metric units?

5. The pressure calculated using force and area measurements was somewhat greater than that calcu-lated using the weight of the books on the large piston or that measured by the sensor. Why was thattrue?


Questions

1. Compare the formula for pressure to the formula for the slope of the graph you created.

2. Why did we believe each syringe would produce equal pressure in this experiment?


13

Experiment 3: Understanding Boyle's Law

Purpose: Unlike liquids, which have a relatively constant volume, a sample of gas mayvary greatly in volume. The volume and pressure are related by a mathematical formula,called Boyle's law. This lab provides data that may be analyzed to discover this formula.Air or another gas may be used.

Procedure:

1. Set up the system (as described on pages 4-5). Keep thesystem free of water, as much as possible. (see setup inFigure 3.1)

2. Attach any small syringe to the sidearm of the tee part(s). If possible, arrange to use a pressure sensor. Thesensor attaches to the sidearm of part (i). Part (i) at-taches between parts (f) and (g). (Figure 3.1)

Note: If you are not using a pressure sensor, lubricatingthe large syringe is important. Use glycerine or siliconeoil. To avoid damaging the seals, do not use a petroleum-based lubricant.

3. Close valve (g) by turning the handle at right angles to the tubing. If using a gas other than air, connecta balloon containing the gas to the unattached end of the hose assembly (d). If using air, leave the endunattached.

4. Now pump the small syringe until the large syringe piston goes up to the 20 cc mark. Open the valvewhile pushing the large syringe platform down, and then close the valve again. This expels any gaspreviously used. Use the small syringe to pump the large syringe piston up to the 50 cc mark.

Equipment Required:• Hydraulic/Pnuematic System (SE-8674) • Glycerine or Silicone oil• DataStudio®, version 1.5 or later* • ScienceWorkshop® interface*• Stack of Books • Absolute Pressure Sensor (CI-6532A)*• Balloons • Ruler

*DataStudio, a ScienceWorkshop interface, and Absolute Pressure Sensor are recommended, but not required.

PRESSURE

SENSOR

0-700 kPa

(ABSOLUTE)

CI-6532A

700 kPa MAX

DRY AIR ONLY


CONNECTOR:


C

(g)

(f)

(i)

Figure 3.1

5. If a pressure sensor is being used, you may skip this step. If no pressure sensor is available, find theweight of the books in newtons. Hang them from a force sensor or spring scale using a loop of string.Alternately, a balance may be used to find mass and the weight calculated. Much effort will be saved ifidentical books can be used. Otherwise, you will need to weigh and record the weight of each book,(and carefully document the order that you stack the books on the platform in step 6).

6. Add one textbook to the platform at a time, carefully centering and balancing the stack each time.After adding each textbook, wait a minute for the volume and pressure to stabilize. Then record thevolume of the gas in the large syringe. If a pressure sensor is being used, also record the pressureunder the column "Total Pressure." The columns, "Total Weight of Books" and "Pressure due to

7. If no pressure sensor is available, an additional step may increase your accuracy. Remove thebooks, one by one, and record the volumes and total weight of the remaining books after each bookis removed.

(d)


14

Calculations and Analysis

Boyle's law states that the pressure of a gas sample times its volume is constant, assuming aconstant temperature.

If you used a pressure sensor, you can test this by calculating P x V for the gas sample foreach of the six pressures. Then you can skip ahead to the questions.


Table 3.1

Your volume readings, as you stacked the books on the piston, are likely too large. The corre-sponding readings, as you removed the books from the piston, are likely too small. (Do you seewhy?) Average the two volumes for one book, the two volumes for two books, etc., and enterthe average values into the table. The pressure due to the weight of the books may be calculatedby the formula,

Pressure=force/area

P x V

The force is the weight of the books. Area is the area of the circular end of thepiston, 5.51 x 10-4m2.

Calculate these pressure values and enter them into the table under "Pressure due tobooks."

The total pressure of the gas sample is greater than this because the earth's atmosphere presses downon the syringe. At sea level, on a typical day, this pressure amounts to 101 kPa, or 101 x 103 N/m2.In Table 3.1, add this value to the values in the "Pressure due to books" column to give the valuesfor the "Total Pressure" column. If you know the actual atmospheric pressure for your location, usethat value instead.

Boyle's Law says that the product of pressure and volume for a gas sample is constant if temperatureis constant.

Calculate P x V for each of the rows of the table. Do the results agree with Boyle's Law, consideringuncertainty?

If you don't have pressure data, proceed to the next steps.

Number ofBooks

Volume(cc)

Total weight ofbooks (N)

Pressure due tobooks (kPa)

Total Pressure(kPa)

123456


15

Teacher's Guide

Experiment 1:

Procedure Notes and Observations:

4. The force required to lift the books on the hydraulic system is much less than if youwere to lift the books directly.

5. The distance the small piston moves is much greater than the distance the books arelifted.

6. Pushing the syringe pushes the water toward the large piston. Pulling the syringe outcreates a suction that pulls water from the beaker into the syringe. If the open tubingends are not completely submerged in the container of water, air will enter the system.

7. Opening the valve reduces the pressure in the hydraulic system. The large piston fallsback to the baseline (zero mark.) The water from the large syringe travels through thevalve and into the beaker.

Sample Data

Forcein

(Newtions)Distance

in

(m)Force

out

(Newtons)IMAAMA Work

in

(Joules)Work

out

(Joules)Syringe Distance

out

(m)Efficiency(%)

3 cc6 cc12 cc20 cc

7.013.618.930.5

.048

.048

.063

.063

41.141.141.141.1

.0054

.0108

.0216

.0360

5.93.02.21.4

8.94.42.91.8

.34

.651.21.9

.22

.44

.891.48

65%68%75%78%

6.12 x 10-5 m2

1.25 x 10-4 m2

1.91 x 10-4 m2

3.13 x 10-4 m2

5.51 x 10-4 m2

AreaSyringe Diameter Length (m)Volume

(m2)(m)

3 cc6 cc12 cc20 cc60 cc

8.83 x 10-3 m1.26 x 10-2 m1.56 x 10-2 m2.00 x 10-2 m2.65 x 10-2 m

0.0490.0480.0630.0640.109


16

Answers to Questions:

1. Some examples of hydraulic systems used in industry include hydraulic brakes in automobiles,hydraulic jacks to lift cars, and hydraulic presses.

2. The ideal mechanical advanatage (IMA) is always larger because the IMA assumes there are noforces working against the machine under study. The actual mechanical advantage and IMA areequal where friction (such as the friction working between the plunger and the syringe cavity),dissipation of thermal energy, water turbulence and air resistance (such as bubbles) are negli-gible. In the ideal condition, there is no wasted energy or work.

3. The only parameters that are the same for the small and large syringe are the force per unit areaand the volume of liquid transferred.

4. The ratio of the areas of the large and small cylinders can also be used to calculate the IMA.

5. Yes, the efficiency is different for different systems. In general, the efficiency increases whenyou go up in syringe size because less strokes (and thus work) are required to move the piston inthe apparatus upward. Also, friction may be a smaller percentage of the total Force

in.

6. The two ways to calculate efficiency are Workout

/Workin

and AMA/IMA.

Experiment 1: (Results Continued):

Experiment 2:


1. The graph will show the force increasing linearly with the area. (This is true while the pressureremains constant.)

2. The slope is approximately constant. The pressure was also constant in this experiment. (Note:In some cases, due to experimental error, there may be some small fluctuations in the pressure.)

3. Pressure=Force/Area; (example: 36.44/5.51 x 10-4 = 66,100 N/m2 = 66.1 kPa)

Sample Data

(m2)*Area (V/L)Syringe

VolumeLength

3 cc6 cc12 cc20 cc60 cc

6.12 x 10-5m2

1.25 x 10-4m2

1.91 x 10-4m2

3.13 x 10-4m2

5.51 x 10-4m2

0.049 m0.048 m0.063 m0.064 m0.109 m

*Note: Remember to convert your units tometers. (1 cc = 1 cm3; 100 cm = 1 m )

(m)


17

Experiment 3:

498048504732464045324200

1. The two formulas are essentially the same!

2. Each syringe was used to produce just enough pressure to lift the stack of books. The sameamount of pressure is needed to lift the stack every time.

3. The slope of the graph, which is constant, should be equal to the pressure, which is also constant.

4. 1 kPa = 1000 Pa (1 Pa is defined as 1 N/m2).

5. Part of the force applied serves to counteract friction. If friction could be eliminated, slope andpressure would be equal.

Experiment 2 (Results Continued):

Answers to Questions


3 cc6 cc12 cc20 cc

Pressure xVolume

Number ofBooks

Volume(cc)

Total Weight of Books (N)

Total Pressure (kPa)

123456

50 cc43 cc37 cc33 cc29 cc22 cc

9.9619.5627.5636.6247.2055.20

99.6112.8127.9140.6156.3190.9

(Typical results)

Gauge Pressure(Sensor)

(kPa)

AreaSyringe

7.0 N13.6 N19.0 N30.5 N

StackedMasses (kg)

.711.391.943.11

6.12 x 10-5 m2

1.25 x 10-4m2

1.91 x 10-4 m2

3.13 x 10-4 m2

(m2)

114 x 103

109 x 103

99.5 x 103

97.4 x 103

82 kPa82 kPa82 kPa82 kPa

Force Applied byMasses or Sensor

(N)

Gauge Pressure(Calculated)

(N/m2)


18

Troubleshooting

Problem: I want to use the system with air (or another gas), but the tubing is wet.

Solution(s): Follow the instructions on pages 4-5 for bleeding the system. While bleeding, have a dry,empty container available and place the open ends of the tubing in the container to collect any water. Ifavailable, use a small air-dry vacuum or blow dryer to suck out or eliminate moisture in the tubing.

Problem: The piston in the Hydraulic/Pneumatic apparatus does not move up when I apply pres-sure to the syringe.

Solution(s): Check the following: a) Ensure that tee is attached under the bottom of the stand. Ifthe tee becomes loose, disconnected or mislodged, the hydraulic system is no longer closed to theatmosphere, and water may begin to slowly run out. b) Check to ensure that the valve is closedwhile you are pushing on the syringe.

Problem: The results for pressure do not appear accurate for the volume reading.

Solution(s): a) Before and after changing syringes, ensure that you properly bleed the apparatus(see page 4-5 of this manual for instructions on bleeding the apparatus). b) Take all volume read-ings from the same position on the point or bottom of the syringe. For example, if you take yourfirst reading from the second line on the black plunger, take all subsequent syringe readings on thesecond line on the black plunger. c) If desired, you may calibrate the sensors. Follow the instruc-tions in the DataStudio online help.

Problem: Too many air bubbles are in the hydraulic system.

Solution(s): Follow the instructions for bleeding the system on pages 4-5 of this manual. Ensureyou bleed the system with the valve opened, closed, and also with the apparatus upside down.

Problem: When I apply pressure with the syringe, the large piston pops out.

Solution(s): Use a smaller syringe or take smaller strokes with the syringe. The larger 20 cc syringeintakes and moves a greater volume of water through the large piston than the smaller syringes.With the large syringe, it's possible to pop the piston out with just 3 strokes.


19

Notes


20

Technical Support

Feedback

If you have any comments about the product ormanual, please let us know. If you have any sugges-tions on alternate experiments or find a problem in themanual, please tell us. PASCO appreciates anycustomer feedback. Your input helps us evaluateand improve our product.

To Reach PASCO

For technical support, call us at 1-800-772-8700(toll-free within the U.S.) or (916) 786-3800.

Fax: (916) 786-3292

E-mail: [email protected]

Web: www.pasco.com

Contacting Technical Support

Before you call the PASCO Technical Support staff, itwould be helpful to prepare the following information:

➤ If your problem is with the PASCO apparatus, note:

- Title and model number (usually listed on thelabel);

- Approximate age of apparatus;

- A detailed description of the problem/sequence ofevents (in case you can’t call PASCO right away,you won’t lose valuable data);

- If possible, have the apparatus within reach whencalling to facilitate description of individual parts.

➤ If your problem relates to the instruction manual,note:

- Part number and revision (listed by month andyear on the front cover);

- Have the manual at hand to discuss yourquestions.

Hydraulic/Pneumatic System - Western Washington Universityphysics-astronomy-manuals.wwu.edu/Pasco...

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