Mosbys Respiratory Care Equipment 9th Edition By J.M. Cairo – Test Bank

 

 

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Sample Test

Chapter 03: Manufacture, Storage, and Transport of Medical Gases

 

MULTIPLE CHOICE

 

1.    Which of the following gases support combustion?

Air

Oxygen

Helium

Carbon Dioxide

 

1.    2 only c.             2, 3

2.    1, 2 d.            1, 3, 4

 

 

ANS:      B

Oxygen and air support combustion.  Helium and carbon dioxide are not flammable

 

PTS:       1              REF:       Page 57, Table 3-2

 

2.    Which of the following gases is the least dense?

3.    Carbon dioxide c. Helium

4.    Nitrous oxide d.            Air

 

 

ANS:      C

Helium is the second-lightest element, with a density of 0.165 kg/m3 at 21.1° C and 1 atmospheric pressure (atm). Oxygen is slightly heavier than air, with a density of 1.326 kg/m3 at 21.1° C and 760 mm Hg.

 

PTS:       1              REF:       Page 57, Table 3-3

 

3.    Which gas has been used successfully in the treatment of pulmonary hypertension of the newborn?

4.    Oxygen c.             Nitrous oxide

5.    Nitric oxide d.            Helium-oxygen mixture

 

 

ANS:      B

At very low concentrations (2 to 80 parts per million) combined with oxygen, nitric oxide has been used to successfully treat persistent pulmonary hypertension of the newborn. Nitrous oxide is used as a central nervous system depressant (anesthetic). Helium-oxygen mixtures decrease the work of breathing by decreasing turbulent airflow.

 

PTS:       1              REF:       Page 56

 

4.    In high concentrations, which of the following gases is a potent anesthetic?

5.    Nitric oxide c.             Carbon dioxide

6.    Nitrous oxide d.            Helium-oxygen mixture

 

 

ANS:      B

The major use for nitrous oxide is a central nervous system depressant. As such, it is a potent anesthetic when administered in high concentrations. At very low concentrations (2 to 80 parts per million) combined with oxygen, nitric oxide has been used successfully to treat persistent pulmonary hypertension of the newborn. Carbon dioxide is nonflammable, but it supports combustion. Helium-oxygen mixtures decrease the work of breathing by decreasing turbulent airflow.

 

PTS:       1              REF:       Page 56

 

5.    Which of the following gases is used to decrease the work of breathing associated with severe airway obstruction?

6.    Nitric oxide c.             Helium-oxygen mixture

7.    Nitrous oxide d.            Carbon dioxide–oxygen mixture

 

 

ANS:      C

A helium-oxygen mixture decreases the work of breathing by decreasing turbulent airflow.

 

PTS:       1              REF:       Page 56

 

6.    Chemical pneumonitis and pulmonary edema can be caused by which of the following?

7.    Nitrous oxide

8.    Carbon dioxide

9.    Excess amounts of nitric oxide

10.  A combination of nitric oxide and nitrogen dioxide

 

 

ANS:      D

Nitric oxide and nitrogen dioxide combine to form a potent irritant that can cause chemical pneumonitis and pulmonary edema. Nitrous oxide, which is nicknamed laughing gas, can cause brain damage or death if inhaled without a sufficient oxygen supply.

 

PTS:       1              REF:       Page 56

 

7.    Carbon dioxide can be obtained by which of the following methods?

8.    Heating uranium ore

9.    Combustion of natural gas

10.  Fractional distillation of liquid air

11.  Oxidizing ammonia at high temperatures

 

 

ANS:      B

Unrefined carbon dioxide can be obtained from the combustion of coal, natural gas, or other carbonaceous fuels. Helium can be obtained by heating uranium ore. The two methods most commonly used to prepare oxygen are the fractional distillation of liquid air and the physical separation of atmospheric air. Nitric oxide can be prepared by oxidizing ammonia at high temperatures (i.e., 500° C and above).

 

PTS:       1              REF:       Page 55

 

8.    Which agency is responsible for the regulations that govern the manufacture, storage, and transport of compressed gases?

9.    Bureau of Medical Devices

10.  Compressed Gas Association (CGA)

11.  U.S. Department of Transportation (DOT)

12.  U.S. Food and Drug Administration (FDA)

 

 

ANS:      C

Metal cylinders have been used for storing compressed gases since 1888. Federal regulations issued by the DOT require that all cylinders used to store and transport compressed gases conform to specifications. The FDA sets purity standards for medical gas. The CGA provides standards and safety systems for compressed gas systems.

 

PTS:       1              REF:       Page 57

 

9.    Which agency sets purity standards for medical gases?

10.  CGA

11.  DOT

12.  FDA

13.  International Standards Organization (ISO)

 

 

ANS:      C

The FDA sets purity standards for medical gas. The DOT governs the manufacture, storage, and transport of compressed gases. The CGA sets standards and provides safety systems for compressed gas systems. The ISO is an international agency that sets standards for technology.

 

PTS:       1              REF:       Page 55, Box 3-2

 

10.  Safety systems for medical gases are recommended and provided by:

11.  DOT.

12.  CGA.

13.  FDA.

14.  National Fire Protection Association (NFPA).

 

 

ANS:      B

The CGA sets standards and provides safety systems for compressed gas systems. The FDA sets purity standards for medical gas. The DOT regulates the manufacture, storage, and transport of compressed gases. The NFPA is an independent agency that provides information on fire protection and safety.

 

PTS:       1              REF:       Page 54, Box 3-2

 

11.  A cylinder has “DOT 3AA 2015” stamped on it. What does the 3AA stand for?

12.  Ownership mark c.             Non–heat-treated carbon-steel

13.  Manufacturer’s mark d.            Heat-treated, high-strength steel

 

 

ANS:      D

3AA stands for heat-treated, high-strength steel. Type 3A cylinders are made of carbon-steel (non–heat-treated).

 

PTS:       1              REF:       Page 57

 

12.  A cylinder has “DOT 3AL 2015” stamped on it. What does the 3AL stand for?

13.  Manufacturer’s initials

14.  Constructed of heat-treated, high-strength steel

15.  Required to undergo hydrostatic testing every 3 years

16.  Constructed of specially prescribed seamless aluminum alloys

 

 

ANS:      D

3AL means that the cylinder is constructed of specially prescribed seamless aluminum alloys and must be examined every 5 years to test its expansion characteristics. Type 3AA is constructed of heat-treated, high-strength steel.

 

PTS:       1              REF:       Page 57

 

13.  Which type of cylinder is produced from non–heat-treated carbon-steel?

14.  3 c.             3AA

15.  3A d.            3AAA

 

 

ANS:      B

3AA means heat-treated, high-strength steel; 3 and 3AAA are not applicable.

 

PTS:       1              REF:       Page 56

 

14.  If the maximum filling pressure is marked as 2050 lb-force per square inch gauge (psig), this cylinder is capable of holding _____ psig.

15.  1845 c.             2255

16.  2050 d.            2460

 

 

ANS:      C

Compressed gas cylinders should be capable of holding up to 10% more than the maximum filling pressure as marked. 10% ´ 2050 = 205 + 2050 = 2255 psig.

 

PTS:       1              REF:       Page 57

 

15.  An asterisk following the reexamination date on a cylinder indicates that the cylinder:

16.  has passed the test. c.             must be retested every 10 years.

17.  must be retested every 5 years. d.            has been sold to another company.

 

 

ANS:      C

An asterisk after the reexamination date on the cylinder markings (see Figure 3-4) indicates that the cylinder must be retested every 10 years.

 

PTS:       1              REF:       Page 57

 

16.  Which size cylinder would be most appropriate for use during patient transport?

17.  H c.             M

18.  G d.            E

 

 

ANS:      D

Size “E” cylinders are used for emergencies and for transport. The other cylinders are too large to be used for transport.

 

PTS:       1              REF:       Page 60

 

17.  Which of the following is not marked on a cylinder?

18.  Ownership marks

19.  Method of production

20.  Serial number of the cylinder

21.  Type of material used to construct the cylinder

 

 

ANS:      B

The method of production is not required to be on the cylinder. All the other options are a requirement.

 

PTS:       1              REF:       Pages 60-61

 

18.  A plus sign after an examination date indicates that the cylinder:

19.  may be retested in 5 years.

20.  may be retested in 10 years.

21.  has been sold to another company.

22.  has complied with the requirements of the test.

 

 

ANS:      D

The plus sign means that the cylinder has complied with the requirements of the test. An asterisk following the reexamination date on the cylinder markings indicates that the cylinder must be retested every 10 years.

 

PTS:       1              REF:       Page 61

 

19.  The color codes for cylinders are prescribed by the:

20.  U.S. National Formulary. c.             FDA.

21.  CGA. d.            American Standards Association.

 

 

ANS:      A

The U.S. National Formulary sets the color-code standards.

 

PTS:       1              REF:       Page 61

 

20.  What is the cylinder color for nitrous oxide?

21.  Red c.             Brown

22.  Black and white d.            Light blue

 

 

ANS:      D

Nitrous oxide is light blue. Ethylene is red. Compressed air is black and white. Helium is brown. See Table 3-4.

 

PTS:       1              REF:       Page 61, Table 3-4

 

21.  What is the international color code for compressed air?

22.  Gray c.             Yellow

23.  Black d.            Black and white

 

 

ANS:      D

The international color code for compressed air is black and white. Yellow is the color set by the U.S. National Formulary.

 

PTS:       1              REF:       Page 61

 

22.  Which of the following appear(s) on the labels of gas cylinders?

23.  Chemical symbol of the contents

24.  Precautionary measures for the gas

25.  Specific hazards related to use of the gas

26.  Volume of the cylinder marked in liters at 70° F

27.  1 c.             1, 2, and 3

28.  1 and 4 d.            1, 2, 3, and 4

 

 

ANS:      D

The CGA and the American Standards Association specify that all labels should include the chemical symbol of the contents, precautionary measures, specific hazards related to the gas, and the volume of the cylinder marked in liters at 70° F.

 

PTS:       1              REF:       Page 62

 

23.  Which agency sets standards for the purity of medical gases?

24.  U.S. National Formulary c.             FDA

25.  CGA d.            American Standards Association

 

 

ANS:      C

Only the FDA sets the purity standards for medical gases.

 

PTS:       1              REF:       Page 62

 

24.  A 97% purity standard is required for which of the following gases?

25.  Ethylene c.             Nitric oxide

26.  Nitrogen d.            Nitrous oxide

 

 

ANS:      D

See Table 3-4.

 

PTS:       1              REF:       Page 61, Table 3-4

 

25.  What is the purity standard for oxygen?

26.  99% c.             97%

27.  98% d.            95%

 

 

ANS:      A

See Table 3-4.

 

PTS:       1              REF:       Page 61, Table 3-5

 

26.  Which of the following statement(s) is (are) true about cylinder valves?

27.  Diaphragm valves can withstand pressure greater than 1500 psig.

28.  Direct-acting valves are used for pressure less than 1500 psig.

29.  Diaphragm valves should be used with flammable gases.

30.  Leakage cannot occur with direct-acting valves.

31.  3 c.             2 and 3

32.  1 d.            1 and 4

 

 

ANS:      A

Diaphragm valves can withstand pressures less than 1500 psig and should be used with flammable gases because they do not allow leaks. A direct-acting valve contains two washers and a Teflon packing to prevent gas leakage around the threads.

 

PTS:       1              REF:       Page 63

 

27.  Which of the following statement(s) is (are) not true about cylinder valves?

28.  Diaphragm valves cannot withstand pressure greater than 1500 psig.

29.  Direct-acting valves are used for pressure greater than 1500 psig.

30.  Diaphragm valves should not be used with anesthetic gases.

31.  Stem leakage can occur with direct-acting valves.

32.  3 c.             1 and 4

33.  2 and 4 d.            1, 2, and 3

 

 

ANS:      A

Diaphragm valves are ideal for situations in which no gas leaks can be allowed, such as with flammable anesthetics.

 

PTS:       1              REF:       Page 63

 

28.  Which of the following statement(s) is (are) true about diaphragm type of valves?

29.  A partial rotation of a diaphragm type of valve will not open the stem.

30.  The valve seat in a diaphragm type of valve does not turn.

31.  The diaphragm type of valve contains two fiber washers.

32.  The diaphragm type of valve uses a threaded stem.

33.  2 c.             3 and 4

34.  1 and 4 d.            2 and 4

 

 

ANS:      D

The valve seat does not turn and is therefore resistant to scoring; it also uses a threaded stem in place of the packing found on the direct-acting valves. The direct-acting valve has two fiber washers.

 

PTS:       1              REF:       Page 63

 

29.  The diaphragms of a diaphragm type of valve are made of:

30.  steel.

31.  copper.

32.  aluminum.

33.  chrome-molybdenum.

34.  2 c.             3 and 4

35.  2 and 3 d.            1 and 2

 

 

ANS:      D

The diaphragm type of valve has two diaphragms, one made of steel and one made of copper. Aluminum and chrome-molybdenum are metals that are used in the construction of cylinders.

 

PTS:       1              REF:       Page 63

 

30.  Wood’s metal is used to make:

31.  gas cylinders.

32.  fusible-plug pressure-relief valves.

33.  rupture-disk pressure-relief valves.

34.  spring-loaded pressure-relief devices.

 

 

ANS:      B

Fusible-plug pressure-relief valves are made of a metal alloy that melts when the temperature of the gas in the tank exceeds a predetermined temperature. This is called Wood’s metal.

 

PTS:       1              REF:       Page 64

 

31.  Which type of valve operates on the principle that as the pressure in a cylinder increases, the temperature of the gas increases?

32.  Direct-acting valves c.             Rupture-disk pressure-relief valves

33.  Fusible-plug pressure-relief valves d.            Spring-loaded pressure-relief valves

 

 

ANS:      B

Fusible-plug pressure-relief valves operate on the principle that as the pressure in a tank increases, the temperature of the gas increases, causing the plug to melt. Spring-loaded devices are designed to release excessive cylinder pressure and reseal, preventing further release of gas from the cylinder after the cause of the excessive pressure is removed. The rupture-disk will buckle when the pressure inside the cylinder exceeds a certain predetermined limit. Direct-acting valves are not pressure-relief valves; instead, they are controlling devices that seal the contents of a compressed cylinder until it is ready for use.

 

PTS:       1              REF:       Page 58, Box 3-2

 

32.  Which agency designed the safety systems for outlet connections of cylinder valves?

33.  Z-79 Committee

34.  CGA

35.  FDA

36.  American National Standards Institute (ANSI)

 

 

ANS:      B

The CGA designed the safety systems for outlet connections of cylinders. The Z-79 Committee establishes standards for anesthetic and ventilatory devices. The FDA sets purity standards. ANSI is a private nonprofit organization that coordinates the voluntary development of national standards in the United States.

 

PTS:       1              REF:       Page 64

 

33.  Medical gas cylinder valve outlets always have connections that are _____-handed and _____.

34.  right; external c.             left; external

35.  right; internal d.            left; internal

 

 

ANS:      A

External and right-handed is the standard for medical gas cylinder valve outlets.

 

PTS:       1              REF:       Page 66

 

34.  Which safety system is used with small cylinders, sizes “A” through “E”?

35.  Pin Index Safety System

36.  Diameter Index Safety System

37.  Direct-Acting Valve Safety System

38.  American Standard Index Safety System

 

 

ANS:      A

Small cylinders (i.e., sizes “A” to “E”) with post type of valves use a different American Standard indexing system called the Pin Index Safety System.

 

PTS:       1              REF:       Page 65, Figure 3-8

 

35.  The cylinder outlet diameter for a “G” size oxygen cylinder is _____ inches.

36.  0.830 c.             0.960

37.  0.903 d.            0.965

 

 

ANS:      B

See Figure 3-8.

 

PTS:       1              REF:       Page 65, Figure 3-8

 

36.  A nitrous oxide “H” size cylinder cannot be attached to oxygen equipment because the nitrous oxide cylinder has which of the following?

37.  A different outlet size

38.  A different thread type

39.  An outer threading system

40.  Internal threading; and oxygen has an external threading

41.  1, 2, 3, and 4 c.             2 and 3

42.  2, 3, and 4 d.            1 and 2

 

 

ANS:      D

See Figure 3-8.

 

PTS:       1              REF:       Page 65, Figure 3-8

 

37.  Which of the following types of threading does a compressed air cylinder have?

38.  Right-handed

39.  Left-handed

40.  Internal

41.  External

42.  2 and 3 c.             2 and 4

43.  1 and 4 d.            1 and 3

 

 

ANS:      B

See Figure 3-8.

 

PTS:       1              REF:       Page 66, Figure 3-9

 

38.  What are the pin positions for an “E” size oxygen cylinder?

39.  2 and 4 c.             2 and 6

40.  2 and 5 d.            3 and 5

 

 

ANS:      B

See Figure 3-9.

 

PTS:       1              REF:       Page 66, Figure 3-9

 

39.  What are the pin positions for an “E” size compressed air cylinder?

40.  1 and 5 c.             2 and 5

41.  1 and 6 d.            3 and 5

 

 

ANS:      A

See Figure 3-9.

 

PTS:       1              REF:       Page 66, Box 3-4

 

40.  Which of the following procedures should be followed in setting up a compressed gas cylinder at a patient’s bedside?

41.  Inspect the cylinder and valve for dirt, debris, and oil.

42.  Make sure the cylinder is properly secured.

43.  Tighten the regulator with a pipe wrench.

44.  Open the cylinder valve completely.

45.  3 and 4 c.             1, 2, 3, and 4

46.  1 and 2 d.            1, 2, and 4

 

 

ANS:      B

See Box 3-4.

 

PTS:       1              REF:       Page 66, Box 3-4

 

41.  The best position for the cylinder valve when it is being used is:

42.  completely open.

43.  two turns toward the left.

44.  one turn, open toward the right.

45.  one half-turn back from completely open.

 

 

ANS:      D

See Box 3-4.

 

PTS:       1              REF:       Page 67

 

42.  After connecting an oxygen regulator to an “H” cylinder and turning the direct-acting valve on, the respiratory therapist attempts to turn on the flow of oxygen. The desired gas flow is not achieved. Which of the following is (are) the most likely problem(s)?

43.  The therapist is using the wrong regulator.

44.  The pressure in the cylinder is inadequate.

45.  The regulator outlet is obstructed.

46.  There is a leak in the connection between the cylinder outlet and the regulator.

47.  1 c.             2 and 3

48.  2 and 4 d.            1, 2, and 4

 

 

ANS:      C

Failure to achieve a desired gas flow from a cylinder regulator can result from inadequate pressure or from an obstruction at the regulator outlet. There would be a hissing noise if there was a leak. Safety systems prevent the wrong regulator from fitting an oxygen cylinder.

 

PTS:       1              REF:       Page 67

 

43.  An “E” size cylinder is turned on, and the flowmeter is off. Which of the following is (are) the most likely cause(s) of a hissing sound?

44.  A cracked flowmeter

45.  Inadequate pressure in the cylinder

46.  An obstruction at the regulator outlet

47.  A leak in the connection between the yoke and the cylinder opening

48.  2 c.             1 and 3

49.  1 and 2 d.            1 and 4

 

 

ANS:      D

A hissing noise means that there is a leak somewhere in the system. Typically, that will occur between the yoke and the cylinder opening or if there is a crack in the flowmeter. Inadequate pressure or an obstruction would not cause a hissing sound.

 

PTS:       1              REF:       Page 67

 

44.  A full “H” size cylinder is used to provide oxygen to an air-entrainment mask at 6 L/min. If the cylinder is replaced at 500 psig, how long will it last?

45.  5 hours c. 10 hours 50 minutes

46.  10 hours 20 minutes d.            15 hours 23 minutes

 

 

ANS:      D

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). H cylinder factor = 3.14. Full-size “H” cylinder = 2265 psig. If the cylinder is changed at 500 psi, then 2265 – 500 = 1765 (1765 psi will be used). (3.14 ´ 1765)/6 L/min = 923.7 minutes/60 = 15 hours (0.39 ´ 60) = 15 hours 23 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

45.  An “E” size cylinder with 1600 psig is used to provide oxygen to a simple mask running at 5 L/min during a transport. The cylinder will last:

46.  8 hours. c.             68 minutes.

47.  56 minutes. d.            89 minutes.

 

 

ANS:      D

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). “E” size factor = 0.28. A simple mask should run at a minimum of 5 L/min. Therefore, (1600 ´ 0.28)/5 L/min = 448/5 = 89.6 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

46.  An “E” size oxygen cylinder with 2000 psig in it is being used at 4 L/min. How much will be used in 45 minutes?

47.  26.2 psig c.             180 psig

48.  140 psig d.            643 psig

 

 

ANS:      D

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). (2000 ´ 0.28)/4 = 140 minutes to use up 2000 psig. Therefore, 2000 psig/140 min = X psig/1 minute X = 14.3 psig/min ´ 45 minutes = 642.8 psig.

 

PTS:       1              REF:       Page 67, Box 3-5

 

47.  A “G” size oxygen cylinder with 1450 psig is being used at 5 L/min. This cylinder will be empty in approximately _____ hour(s) and _____ minutes.

48.  1; 30 c.             11; 30

49.  2; 39 d.            15; 16

 

 

ANS:      C

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). “G” size cylinder factor = 2.41. Amount of time = (1450 ´ 2.41)/5 = 698.9 minutes/60 = 11 hours 39 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

48.  The K cylinder at a patient’s bedside contains 1300 psig and is using 7 L/min. It will take approximately _____ hours to use 800 psig.

49.  3.7 c.             6

50.  9.7 d.            4

 

 

ANS:      C

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). K factor = 3.14. Time to use 800 psi = (800 ´ 3.14)/7 = 358.8 min/60 = 5 hours 59 minutes.

 

PTS:       1              REF:       Page 57, Box 3-5

 

49.  The E cylinder on a crash cart contains 900 psig. How long would the cylinder last if used at 10 L/min?

50.  1 hour c.             3 hours 36 minutes

51.  25 minutes d.            4 hours 42 minutes

 

 

ANS:      B

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). E factor = 0.28. Time to use 900 psig = (900 ´ 0.28)/10 = 25 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

50.  A “G” size cylinder with 2000 psig is used for 6 hours at 5 L/min. How much gas was used during this time?

51.  2000 psig c.             573 psig

52.  750 psig d.            107 psig

 

 

ANS:      B

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). G factor = 2.41. Time to use 2000 psig = (2000 ´ 2.42)/5 = 964 minutes/60 = 16 hours. 2000 psig /16 hours = X psig/6 hours. X = 750 psig will be used in 6 hours at 5 L/min.

 

PTS:       1              REF:       Page 67, Box 3-5

 

51.  Which of the following statements is (are) true with regard to liquid bulk systems?

52.  Liquefied oxygen occupies a fraction of the space required for the storage of gaseous oxygen.

53.  The CGA regulates the construction of liquid oxygen systems.

54.  A bulk oxygen system contains more than 40,000 ft of oxygen.

55.  The working pressure of a liquid bulk oxygen system is 50 psig.

56.  2 c.             1 and 3

57.  3 and 4 d.            1 and 4

 

 

ANS:      D

See Box 3-6.

 

PTS:       1              REF:       Page 68, Box 3-6

 

52.  The function of the vaporizer of a liquid bulk oxygen system is to:

53.  act as a pressure release.

54.  reduce the pressure to 50 psig.

55.  convert liquid oxygen to gaseous oxygen.

56.  allow heat to be released into the environment.

 

 

ANS:      C

The reservoir stores a mixture of liquid and gaseous oxygen. The vaporizer acts as a heat exchanger where heat is absorbed from the environment and used to warm the liquid oxygen to room temperature, thus forming gaseous oxygen.

 

PTS:       1              REF:       Page 67

 

53.  The gas above liquid oxygen is maintained:

54.  between its freezing point and its critical temperature.

55.  between its boiling point and its critical temperature.

56.  at its critical pressure.

57.  at its boiling point.

 

 

ANS:      B

The pressure-release valve allows some of the gas on top of the liquid to escape if the contents are warmed too much. This release of gas allows the gas within the container to expand, thus lowering the temperature. This maintains the gas under pressure between its boiling point and its critical temperature so that the majority of the reservoir’s contents will be maintained in the liquid state.

 

PTS:       1              REF:       Page 67

 

54.  The application of Gay-Lussac’s law in a bulk liquid oxygen system:

55.  accounts for the conversion of the liquid oxygen to gaseous oxygen.

56.  allows the reservoir contents to be maintained in the liquid state.

57.  keeps the liquid oxygen above its critical temperature.

58.  allows the gas to be maintained at 50 psig.

 

 

ANS:      B

According to Gay-Lussac’s law, if the volume of a gas remains constant, there is a direct relationship between the absolute pressure of a gas and its temperature. This release of gas allows the gas within the container to expand, thus lowering the temperature.

 

PTS:       1              REF:       Page 67

 

55.  Which of the following are components of a bulk liquid oxygen system?

56.  3AA container

57.  Insulated reservoir

58.  Pressure-release valve

59.  A heater for the liquid oxygen

60.  2 and 3 c.             2 and 4

61.  1 and 3 d.            1 and 4

 

 

ANS:      A

A bulk liquid oxygen system consists of an insulated reservoir, a vaporizer with associated tubing attached to the reservoir, a pressure-reducing valve, and an appropriate pressure-release valve.

 

PTS:       1              REF:       Page 67

 

56.  The NFPA requires bulk oxygen systems to be located:

57.  10 feet from flammable gas storage.

58.  10 feet from public sidewalks.

59.  5 feet from the property line.

60.  5 feet from congested areas.

61.  1 and 4 c.             2, 3, and 4

62.  2 and 3 d.            1, 2, 3, and 4

 

 

ANS:      B

See Box 3-6.

 

PTS:       1              REF:       Page 70, Figure 3-11

 

57.  According to the NFPA, for a nonambulatory patient, the minimum distance from a bulk oxygen supply is _____ feet.

58.  5 c.             25

59.  10 d.            50

 

 

ANS:      D

See Figure 3-11.

 

PTS:       1              REF:       Page 70, Figure 3-11

 

58.  One liter of liquid oxygen weighs _____ oz.

59.  25 c.             86

60.  40 d.            860

 

 

ANS:      B

One liter of oxygen weighs 2.5 lb. 2.5 lb ´ 16 oz/lb = 40 oz.

 

PTS:       1              REF:       Page 69

 

59.  A home care patient inquires about how long her portable liquid oxygen system, currently weighing 30 lb, will last if she uses 3 L/min. The manufacturer says the weight of an empty container is 8 lb. Her system will last for _____ day(s) and _____ hours.

60.  1; 18 c.             4; 21

61.  2; 9 d.            8; 12

 

 

ANS:      A

First subtract 8 lb from 30 lb = 22 lb. Convert 22 lb/2.5 lb/L = 8.8 L. 8.8 L ´ 860 (liter of liquid oxygen multiplied by 860 equals the liters of gaseous oxygen) = 7568 L. Then divide by liter flow. 7568/3 L/min = 2522 min = 1 day 18 hours.

 

PTS:       1              REF:       Page 70, Box 3-7

 

60.  If a portable liquid oxygen reservoir is set to deliver 6 L/min and the current reservoir weight is 38 lb, it will take _____ hours for the reservoir to empty if the weight of an empty container is 10 lb.

61.  5 c.             27

62.  23 d.            36

 

 

ANS:      C

Subtract 10 lb from 38 lb = 28 lb. Convert 28 lb/2.5 lb/L = 11.2 lb. 11.2 lb ´ 860 = 9632 L. Then divide by liter flow: 9632 L/6 L/min = 1605 minutes, or 27 hours.

 

PTS:       1              REF:       Page 70, Box 3-7

 

61.  Approximately how long will a liquid oxygen reservoir last when supplying 3 L/min to your patient? The current reservoir weight is 20 lb, and the weight of an empty reservoir is 10 lb.

62.  19 hours c.             46 hours

63.  38 hours d.            119 hours

 

 

ANS:      A

Subtract 10 lb from 20 lb = 10 lb. Convert 10 lb/2.5 lb/L= 4 L. 4 ´ 860 = 3440 L. Then divide by the flow 3440 L/3 L/min = 1146 minutes, or 19 hours.

 

PTS:       1              REF:       Page 70

 

62.  During your home care visit on Monday morning, you weigh the patient’s portable liquid oxygen reservoir. The liquid oxygen weighs 18 lb, and the patient is using 2 L/min. When should you schedule a visit to fill up the reservoir?

63.  The next Monday c.             Thursday afternoon

64.  Wednesday morning d.            Friday afternoon

 

 

ANS:      B

18 lb/2.5 lb/L=7.2 L. 7.2 L ´ 860 = 6192 L/2 L/min = 3096 minutes, or 51 hours 36 minutes, which is 2 days 3 hours 36 minutes. So it would have to be filled on Wednesday.

 

PTS:       1              REF:       Page 70, Box 3-7

 

63.  Which of the following types of compressor can accommodate a mechanical ventilator?

64.  Diaphragm

65.  Liquid air

66.  Rotary

67.  Piston

68.  1 c.             3 and 4

69.  2 and 4 d.            1, 3, and 4

 

 

ANS:      C

Rotary compressors use a rotating vane to compress air from an intake valve. As the rotating vane turns, gas is drawn into the cylinder through a one-way valve (Figure 3-16). The rotor turns, which causes the gas to be compressed as the oval-shaped cylinder becomes smaller. The compressed gas is then forced out of the compressor through another one-way outflow valve. Low-pressure rotary compressors are used in ventilators such as the Bennett MA-1. Piston compressors use the action of a motor-driven piston to compress atmospheric air. The piston is seated within a cylinder casing and is sealed to it with a carbon or Teflon ring. Figure 3-14 illustrates the operational principle of a typical piston air compressor used to power a mechanical ventilator.

 

PTS:       1              REF:       Page 73

 

64.  Which of the following is (are) a small nebulizer compressor(s)?

65.  Diaphragm

66.  Liquid air

67.  Rotary

68.  Piston

69.  4 c.             1 and 2

70.  1 d.            1, 3, and 4

 

 

ANS:      B

A flexible diaphragm is attached to a piston to compress gas. As the piston moves down, the diaphragm is bent outward and gas is drawn through a one-way valve into the cylinder. Upward movement of the piston forces the gas out of the cylinder through a separate one-way outflow valve. Examples of diaphragm compressors are the Air Shields Diapump and the DeVilbiss small nebulizer compressor.

 

PTS:       1              REF:       Page 73

 

65.  Which of the following agencies makes recommendations for medical air supply?

66.  ISO c.             CGA

67.  NFPA d.            Bureau of Medical Devices

 

 

ANS:      B

See Box 3-8.

 

PTS:       1              REF:       Page 72, Box 3-8

 

66.  Which of the following statements about medical air supplies are false?

67.  The air intake port must be located indoors.

68.  The source of medical air must be from the outside atmosphere.

69.  Most hospital bulk air supply systems use two compressors.

70.  Backflow through the compressors that are cycled off must be prevented manually.

71.  1 and 4 c.             2 and 3

72.  1, 2, and 3 d.            3 and 4

 

 

ANS:      A

See Box 3-8.

 

PTS:       1              REF:       Page 72, Box 3-8

 

67.  Which of the following type(s) of air compressors is (are) used in bulk supply systems?

68.  Piston

69.  Rotary

70.  Liquid air

71.  Diaphragm

72.  1 and 4 c.             1 and 2

73.  1 and 3 d.            2

 

 

ANS:      C

To power a bulk air supply, either a piston or a rotary compressor is necessary. Liquid air is not used as a source for bulk supply. A diaphragm air compressor could not keep up with the requirements of a bulk system.

 

PTS:       1              REF:       Page 54, Box 3-2

 

68.  The NFPA requires that bulk oxygen systems be at least how many feet from parked vehicles?

69.  5 c.             15

70.  10 d.            20

 

 

ANS:      B

See Figure 3-11.

 

PTS:       1              REF:       Page 70, Figure 3-11

 

69.  If the working pressure of a bulk oxygen system is 45 psig, all pressure-relief valves should be set at _____ psig.

70.  45 c.             67

71.  50 d.            80

 

 

ANS:      C

All pressure-relief valves are set 50% higher than the system working pressure (e.g., set at 75 psi for a 50-psi system pressure).

 

PTS:       1              REF:       Page 74

 

70.  In the event of a fire in a hospital, which of the following might be necessary?

71.  Provide supplemental oxygen to patients who require it.

72.  Shut off oxygen zone valves to the affected area.

73.  Shut off the main oxygen valve.

74.  Check oxygen line pressure.

75.  3 c.             2 and 4

76.  1 and 2 d.            3 and 4

 

 

ANS:      B

In case of fire, affected zones can be isolated, thus preventing the problem from spreading to other areas of the hospital. And always remember patient safety in terms of applying the appropriate oxygen to each patient.

 

PTS:       1              REF:       Page 74

 

71.  Which of the following are safety features incorporated into a medical gas piping system?

72.  Zone valves

73.  Riser valves

74.  Pressure-relief valves

75.  In-line oxygen analyzers

76.  3 and 4 c.             1 and 4

77.  1 and 3 d.            1, 2, and 3

 

 

ANS:      D

See Figure 3-17.

 

PTS:       1              REF:       Page 75

 

72.  Which safety system(s) is (are) found at station outlets of a medical gas piping system?

73.  Diameter Index Safety System (DISS)

74.  American Standard Safety System (ASSS)

75.  Pin Index Safety System

76.  Quick Connect

77.  1 c.             2 and 3

78.  1 and 4 d.            2 and 4

 

 

ANS:      B

Station outlets are designed with safety systems that prevent the connection of incompatible devices. Two safety systems are currently available: the DISS and Quick-Connect adapters.

 

PTS:       1              REF:       Page 76

 

73.  The type of station outlet connection that uses noninterchangeable thread fittings to connect gas-powered devices to station outlets is known as:

74.  regulator. c.             Pin Index Safety System.

75.  quick-connect adapter. d. DISS.

 

 

ANS:      D

Figure 3-20 shows an outlet that uses DISS. This system, which was designed by the CGA, uses noninterchangeable thread fittings to connect gas-powered devices to station outlets.

 

PTS:       1              REF:       Page 78

 

74.  Which of the following statements are true concerning station outlets?

75.  Check valves are safety valves that close automatically when an adapter is disengaged from the outlet.

76.  Station outlets do not have ASSS connections.

77.  Quick-connect adapters use noninterchangeable thread fittings.

78.  Check valves must hold a minimum of 200 psig.

79.  3 and 4 c.             2 and 4

80.  1, 3, and 4 d.            1 and 2

 

 

ANS:      D

Station outlets have safety valves that close automatically when an adapter is disengaged from the outlet (i.e., quick-connect adapters). The quick-connect adapters and the DISS are the two safety systems that can be at a station outlet.

 

PTS:       1              REF:       Page 76

 

75.  What percentage of oxygen does a typical molecular sieve concentrator provide when it is running at 2 L/min?

76.  100% c.             85%

77.  90% d.            40%

 

 

ANS:      B

The concentration of oxygen leaving the system depends on the flow rate set. For example, at flows less than 6 L/min, the gas contains approximately 92% to 97% oxygen.

 

PTS:       1              REF:       Page 79

 

76.  Which is true about the process of fractional distillation of liquid air?

77.  Compressed air is a by-product.

78.  It produces pure liquid oxygen.

79.  Liquid nitrous oxide is produced.

80.  Concentrators use it to produce oxygen.

 

 

ANS:      B

The fractional distillation of liquid air creates pure liquid oxygen. There are no by-products from this method. Oxygen concentrators take in room air and separate oxygen from nitrogen.

 

PTS:       1              REF:       Page 54, Box 3-1

 

77.  One liter of liquid oxygen is equivalent to _____ liters of gaseous oxygen.

78.  2.5 c.             348

79.  328 d.            860

 

 

ANS:      D

Oxygen expands to 860 times its liquid volume at 25° C and 1 atm; therefore, the total volume of gaseous oxygen available can be calculated by multiplying the number of liters of liquid oxygen by 860.

 

PTS:       1              REF:       Page 67

 

78.  Which of the following statements are true given that, on one side of a medical gas cylinder, the only markings to appear are 3 (tw) 84 + *.

79.  The cylinder passed the hydrostatic test.

80.  The cylinder must be retested after 5 years.

81.  The cylinder must be retested after 10 years.

82.  The cylinder was manufactured in March 1984.

83.  Hydrostatic testing was performed in March 1984.

84.  2, 3, and 4 c.             1, 4, and 5

85.  2, 3, and 5 d.            1, 2, and 4

 

 

ANS:      D

See Figure 3-4.

 

PTS:       1              REF:       Page 61

 

79.  Which of the following statements reflect(s) the recommendations of the NFPA and CGA for storing cylinders outdoors?

80.  Cylinders should not be stored in an area where the temperature exceeds 125° F.

81.  Cylinders must be protected from the weather.

82.  Full and empty cylinders should be kept separate.

83.  Cylinders should not be stored outside.

84.  4 c.             2 and 3

85.  1 and 2 d.            1, 2, and 3

 

 

ANS:      D

See Box 3-3.

 

PTS:       1              REF:       Page 58, Box 3-3

 

80.  Which of the following large-cylinder safety recommendations is not appropriate?

81.  Protective caps are not necessary during storage.

82.  Cylinders should be transported with protective caps.

83.  Cylinder carts used in the operating room must be grounded.

84.  Transportation must occur on an appropriate cart, onto which the cylinder is secured by a chain.

 

 

ANS:      A

Large cylinders have a protective cap that fits over the valve stem. This cap should be kept on cylinders when moving or storing them.

 

PTS:       1              REF:       Page 58, Box 3-3

 

81.  Which of the following types of oxygen storage device are appropriate for home care?

82.  Manifold

83.  Compressor

84.  Concentrator

85.  Bulk oxygen system

86.  Liquid oxygen cylinder

87.  2 and 5 c.             2, 3, and 5

88.  2 and 4 d.            1, 4, and 5

 

 

ANS:      A

Concentrators are used in the home care setting for patients who require low-flow oxygen. Liquid oxygen cylinders can allow the patient more time outside of the home during travel. Manifolds and bulk oxygen systems are not appropriate for home care. Compressors provide medical air, not oxygen.

 

PTS:       1              REF:       Page 79

 

82.  Which of the following have the fastest diffusion rate through the semipermeable membrane of an oxygen concentrator?

83.  Carbon dioxide

84.  Water vapor

85.  Nitrogen

86.  Oxygen

87.  1 and 2 c.             3 and 4

88.  1 and 3 d.            2 and 4

 

 

ANS:      D

Oxygen concentrators are devices that produce enriched oxygen from atmospheric air. Thus, oxygen and water vapor diffuse through these membranes faster than nitrogen.

 

PTS:       1              REF:       Page 77

 

83.  The concentration of oxygen leaving an oxygen concentrator depends on the:

84.  number of sieves in the unit.

85.  number of compressors used.

86.  set flow rate of the gas exiting.

87.  size of the sodium-aluminum silicate pellets.

 

 

ANS:      C

Atmospheric gases diffuse through the membrane at different rates. The rate at which a gas diffuses depends on its diffusion constant and solubility for the plastic membrane and the pressure gradient for the gas across the membrane.

 

PTS:       1              REF:       Page 77

 

84.  Bulk oxygen is produced through which of the following?

85.  Molecular sieves c.             Semipermeable membranes

86.  Fractional distillation d.            Combustion of natural gas

 

 

ANS:      B

Fractional distillation generates bulk oxygen. Molecular sieves and semipermeable membranes are used in oxygen concentrators. The combustion of natural gas produces carbon dioxide.

 

PTS:       1              REF:       Page 54

 

85.  Which of the following gases is used to treat singultus?

86.  Air c.             Nitrous oxide

87.  Oxygen d.            Carbon dioxide

 

 

ANS:      D

Carbon dioxide is used for the treatment of singultus (hiccups) and as a stimulant/depressant of the central nervous system.

 

PTS:       1              REF:       Page 55

 

86.  At –183° C, which of the following gases exists as a pale, bluish liquid that is slightly heavier than water?

87.  Air c.             Nitrous oxide

88.  Oxygen d.            Carbon dioxide

 

 

ANS:      B

Oxygen is an elemental gas that is colorless, odorless, and tasteless at normal temperatures and pressures. It makes up 20.9% of the Earth’s atmosphere by volume and 23.2% by weight. It constitutes approximately 50% of the Earth’s crust by weight. Oxygen is slightly heavier than air, having a density of 1.326kg/m3 at 21.1° C and 760 mm Hg (specific gravity = 1.105). At temperatures less than –183° C (–300° F), oxygen exists as a pale, bluish liquid that is slightly heavier than water.

 

PTS:       1              REF:       Page 54

 

87.  Which of the following gases may be used as a refrigerant?

88.  Oxygen c.             Carbon dioxide

89.  Nitric oxide d.            Carbon monoxide

 

 

ANS:      C

Solid carbon dioxide is used to refrigerate perishable materials during transport (e.g., food and laboratory specimens). Liquid carbon dioxide can be used as an expendable refrigerant and is used extensively as a fire-extinguishing agent in portable and stationary fire-extinguishing systems.

 

PTS:       1              REF:       Page 55

 

88.  Which of the letters points to the manufacturer’s mark?

 

 

1.    A c.             C

2.    B d.            D

 

 

ANS:      B

See Figure 3-4.

 

PTS:       1              REF:       Page 61

 

89.  Which size cylinder is currently used for the storage of nitric oxide?

90.  61.4 cubic feet c.             110 cubic feet

91.  82 cubic feet d.            152 cubic feet

 

 

ANS:      B

Before 1997, nitric oxide was supplied in cylinders with a volume capacity of 152 cubic feet. It is now supplied in smaller cylinders (82 cubic feet) with 626 CGA valve outlets.

 

PTS:       1              REF:       Page 56

 

90.  The cylinder color for nitric oxide is:

91.  red. c.             teal and black.

92.  light blue. d.            brown and green.

 

 

ANS:      C

See Table 3-4.

 

PTS:       1              REF:       Page 61

 

91.  Which gas law is applied in a fusible-plug pressure-relief valve?

92.  Boyle’s c. Dalton’s

93.  Charles’ d.            Gay-Lussac’s

 

 

ANS:      D

The pressure-release valve allows some of the gas on top of the liquid to escape if the contents are warmed too much. This release of gas allows the gas within the container to expand, thus lowering the temperature. This maintains the gas under pressure between its boiling point and its critical temperature so that the majority of the reservoir’s contents will be maintained in the liquid state.

 

PTS:       1              REF:       Page 67

 

92.  The American Standard System connections for all life support gases are _____-handed and _____.

93.  Left; internal c.             Right; internal

94.  Left; external d.            Right; external

 

 

ANS:      D

Note that the connections for oxygen and other life-support gases are right-handed and external.

 

PTS:       1              REF:       Page 64

 

93.  Which of the following is the Pin Index Safety System pin position for oxygen?

 

 

1.    A c.             C

2.    B d.            D

 

 

ANS:      A

Recall that in this system, indexing is accomplished by the exact placement of two pins into holes in the post valve.

 

PTS:       1              REF:       Page 66, Figure 3-9

 

94.  An “E” size oxygen cylinder with 2200 psig has a set flow rate of 2 L/min. It will take _____ hours and _____ minutes until the gauge pressure reaches 400 psig.

95.  5; 30 c.             4; 30

96.  5; 6 d.            4; 12

 

 

ANS:      D

Amount of time left in cylinder = (cylinder pressure ´ cylinder factor)/flow rate of gas (liters/minute). 2200 – 400 = 1800 psig (the amount of gas that will be used). (1800 ´ 0.28)/2 = 252 minutes/60 = 4 hours 12 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

95.  Which of the following “E” size oxygen cylinders will last the longest?

Pressure            Flow

(psig)              (L/min)

1.    1600 3      c.             800                2

2.    1400 2.5   d.            400                1

 

 

ANS:      B

This answer was derived from the following formula:

 

 

 

1400 ´ 0.28 = 392/2.5 L/min = 156.8 minutes.

1400 psig at 2.5 L/min will last the longest compared with the other three.

 

PTS:       1              REF:       Page 67, Box 3-5

 

96.  An “H” size oxygen cylinder with 1600 psig has a set flow rate of 3 L/min. It will take _____ hours and _____ minutes to reach 300 psig.

97.  17; 24 c.             22; 40

98.  21; 25 d.            27; 54

 

 

ANS:      C

The same formula as described in the previous question is used here; however, you first have to subtract 300 psig from 1600 psig to get the exact duration for 1300 psig. (1300 ´ 3.14)/3 = 1360.7 minutes/60 = approximately 22 hours 40 minutes.

 

PTS:       1              REF:       Page 67, Box 3-5

 

97.  The following figure represents the components of which of the following?

 

 

1.    Hydrostatic testing system c.             Fractional distillation apparatus

2.    Bulk liquid oxygen system d.            Alternating oxygen supply system

 

 

ANS:      B

Recall also Figure 3-10.

 

PTS:       1              REF:       Page 68, Box 3-6

 

98.  Which of the following “G” size oxygen cylinders will run out of oxygen first?

Pressure       Flow

(psig)        (L/min)

1.    700 1.5      c.             1100           2.5

2.    900 1.0      d.            1600           3.0

 

 

ANS:      C

This answer was derived from the following formula:

 

 

 

The cylinder factor is 3.14. 1100 psig has the shortest duration at 1382 minutes, or 23 hours.

 

PTS:       1              REF:       Page 67, Box 3-5

 

99.  According to the NFPA, the minimum distance for a place of public assembly from a bulk oxygen storage system is how many feet?

100.          10 c.             25

101.          15 d.            50

 

 

ANS:      D

See Figure 3-11.

 

PTS:       1              REF:       Page 70

 

100.          Storage of a portable liquid oxygen system adjacent to a heat source will _____ the _____ of the oxygen.

101.          Increase; pressure c.             Decrease; pressure

102.          Increase; venting d.            Decrease; venting

 

 

ANS:      B

Liquid oxygen units should not be located adjacent to heat sources, which can accelerate the venting of oxygen.

 

PTS:       1              REF:       Page 72, Box 3-8

 

101.          A stationary liquid oxygen system contains 80 lb of oxygen when full. A home care patient is using it 8 hours each day, during sleep, at a rate of 3 L/min. At this usage, how many days will the liquid oxygen last?

102.          6 c.             19

103.          8 d.            27

 

 

ANS:      C

Use the liquid oxygen duration formula as given previously.

A liter of liquid oxygen weighs 2.5 lb, so: 80 lb/2.5 = 32 L.

Gaseous oxygen occupies a volume that is 860 times the volume of liquid oxygen, so: liters of liquid ´ 860 = liters of gas.

Duration of supply (minutes) = gas supply remaining (in liters) ÷ flow (liters/minute).

Once you get the answer in minutes, you divide by 60 to obtain the number of hours. Then divide the number of hours by the usage, which is 8 hr/day; that gives you 19 days.

 

PTS:       1              REF:       Page 70, Box 3-7

 

Chapter 04: Administering Medical Gases: Regulators, Flowmeters, and

 

MULTIPLE CHOICE

 

1.    What device helps reduce high-pressure gases from cylinders or bulk storage units to a lower working pressure?

2.    Regulator c.             Bourdon gauge

3.    Kinetic tube d.            Thorpe tube

 

 

ANS:      A

The regulator is the only device in which pressure is regulated. The other devices relate to flow.

 

PTS:       1              REF:       Page 84

 

2.    The chamber located above the diaphragm of a single-stage regulator is which of the following?

3.    Lower chamber c.             High-pressure chamber

4.    Pressure-relief valve d.            Adjustable regulator

 

 

ANS:      C

The high-pressure chamber is located above the diaphragm and contains a valve stem that will close the inlet when the pressure reaches its setting.

 

PTS:       1              REF:       Page 84

 

3.    The gas flow into the high-pressure side regulator is dependent on what two opposing forces?

4.    Gas pressure above the diaphragm

5.    Gas pressure at the diaphragm

6.    Spring tension below the diaphragm

7.    Spring tension above the diaphragm

8.    1 and 3 c.             2 and 4

9.    2 and 3 d.            1 and 4

 

 

ANS:      A

When the force offered by the high-pressure gas above the diaphragm equals the force offered by spring tension, the diaphragm is straight and the inlet valve is closed.

 

PTS:       1              REF:       Page 84

 

4.    Delivered pressures on common adjustable regulators are between _____ and ____ pounds per square inch gauge (psig).

5.    0; 50 c.             50; 100

6.    0; 100 d.            50; 200

 

 

ANS:      B

Most adjustable regulators can be set to deliver pressure between 0 and 100 psig.

 

PTS:       1              REF:       Page 84

 

5.    Which regulator supports the theory that gas pressure is gradually reduced as gas flows from a high-pressure source through a series of stages to the outlet?

6.    Single-stage regulator c.             Preset regulator

7.    Flowmeter d.            Multistage regulator

 

 

ANS:      D

Gas from a compressed cylinder (e.g., 2200 psig) enters the first stage of a two-stage regulator, and the gas pressure is reduced to an intermediate pressure (e.g., 700 psig). This lower pressure gas then enters into the second stage of the regulator, where the gas pressure is further reduced to the desired working pressure (e.g., 50 psig) before the gas reaches the outlet.

 

PTS:       1              REF:       Page 85

 

6.    Which device is more precise in terms of controlling gas pressure?

7.    Bourdon flowmeter c.             Multistage regulator

8.    Thorpe tube flowmeter d.            Flow restrictors

 

 

ANS:      C

Multistage regulators can control gas pressure with more precision than single-stage regulators because the pressure is gradually reduced.

 

 

 

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