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

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

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?

ANS: A

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

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

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.

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

1. Gas pressure above the diaphragm

2. Gas pressure at the diaphragm

3. Spring tension below the diaphragm

4. Spring tension above the diaphragm

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.

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

ANS: B

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

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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?

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.

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

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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7. The most commonly used flowmeter in respiratory care is which of the following?

ANS: A

Thorpe tubes are the most commonly used flowmeters in respiratory care.

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8. The problem most often encountered with a Thorpe tube flowmeter is:

ANS: B

This problem is usually detected when the flowmeter is turned off completely, but gas can be heard continuing to flow from the flowmeter outlet; in this case, the flowmeter should be replaced. This problem can also occur because of constant wear and tear.

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9. Pressure-compensated flowmeters provide which of the following?

ANS: B

On pressure-compensated flowmeters, the needle valve controlling gas flow out of the flowmeter is located distal to the Thorpe tube. This arrangement allows the pressure in the indicator tube to be maintained at the source gas pressure, which ensures an accurate estimate of flow.

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10. A float that jumps and falls to zero when the needle valve is closed and is attached to a bulk system is indicative of a _____ flowmeter.

ANS: D

This floating movement occurs because the source gas must pass through the indicator tube before it reaches the needle valve.

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11. Which device uses the following principle? As the driving pressure is increased, the flow from the flowmeter outlet increases.

ANS: C

A Bourdon flowmeter is actually a reducing valve that controls the pressure gradient across an outlet with a fixed orifice.

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12. What is (are) the type(s) of flow restrictor(s)?

1. Fixed-orifice

2. Adjustable, multiple-orifices

3. Compensated orifice

4. Non-compensated orifice

ANS: D

There are two types of flow restrictors: fixed-orifice and adjustable, multiple-orifice models. The adjustable, multiple-orifice flow restrictor uses a series of calibrated openings in a disk that can be adjusted to deliver different flows.

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