Home » Control Valves Multiple Choice Questions
Control Valves Interview Questions Multiple Choice Questions

Control Valves Multiple Choice Questions

Control Valves Multiple Choice Questions

Question 1

When a valve is installed in a process with where the differential pressure (drop) across the valve decreases with increasing flow, the best trim characteristic to choose for the valve would be:

(A) Ported
(B) Quick-opening
(C) Equal percentage
(D) Linear
(E) Anti-cavitation

Answer : C

Question 2

The correct identities of the four control valve types shown below are (in order from left to right):

Control Valve Types

(A) Plug, Slide, Rotary, Ball
(B) Globe, Butterfly, Disc, Ball
(C) Ball, Gate, Butterfly, Plug
(D) Diaphragm, Gate, Disc, Globe
(E) Ball, Disc, Butterfly, Globe

Answer : C

Question 3

An air-to-open valve assembly may be formed with which of these actuator/valve body combinations?

(A) Reverse-acting actuator, direct-acting valve body
(B) Direct-acting actuator, direct-acting valve body
(C) Direct-acting actuator, reverse-acting valve body
(D) A or C
(E) B or C

Answer : D

Question 4

Calculate the necessary Cv rating for a liquid service valve, given a pressure drop of 24 PSID, a specific gravity of 1.3, and a maximum flow rate of 140 GPM. Assume there will be no flashing or choked flow through the valve.

(A) 0.1319
(B) 32.58
(C) 7.583
(D) 2585
(E) 601.5

Answer : B

Question 5

The main purpose of a control valve positioner is to:

(A) Alter the fail-safe status of the valve
(B) Improve the precision of the valve
(C) Alter the characterization of the valve
(D) Increase transmitter accuracy
(E) Eliminate cavitation in the valve

Answer : B

Question 6

The purpose of valve packing is to:

(A) Help reduce cavitation in the valve trim
(B) Increase stiction
(C) Cushion the valve against harm during shipment
(D) Seal process fluid from escaping past the stem
(E) Lubricate the valve trim

Answer : D

Question 7

The definition of split range control valves implies that they are . . .

(A) designed to be easily disassembled.
(B) easily re-ranged for different characteristics.
(C) equipped with quick-acting positioners.
(D) only used in sets of three.
(E) calibrated with complementary ranges.

Answer : E

Question 8

Dual-ported globe valves typically enjoy the following advantage over single-ported globe valves:

(A) Less actuating force required
(B) Longer service life
(C) Easier disassembly and maintenance
(D) Tighter shut-off
(E) Greater temperature range

Answer : A

Question 9

Cavitation in a control valve is caused by:

(A) process noise
(B) vibration in the piping
(C) the Von Karman effect
(D) a laminar flow regime
(E) pressure recovery

Answer : E

Question 10

The proper “fail safe” status of a valve should always be dictated by:

(A) economic savings
(B) the configuration of the positioner
(C) the controller’s tuning
(D) the controller’s action (direct or reverse)
(E) the nature of the process

Answer : E

Valves Objective Questions – Share Your Answers

11. Regardless of type, all valves have the following basic parts, with the exception of ___

a) bonnet
b) nipple
c) actuator
d) body

12. The body of a valve typically receives inlet and outlet piping through any of the following types of joints EXCEPT:.

a) glued
b) welded
c) threaded
d) bolted

13. The internal elements of a valve are collectively referred to as a valve’s .

a) guts b) trim
c) works d) packings

14. The manually operated handwheel, manual lever, motor operator, solenoid operator, pneumatic operator, or hydraulic ram are all examples of

a) a yoke
b) a stem
c) a bonnet
d) an actuator

15.Which one of the following valve parts is NOT usually considered to be a part of the pressure boundary.

a) body
b) seal rings
c) bonnet
d) disk

16.The stem in a valve, which connects the actuator and disk, is responsible for positioning the disk.

a) True
b) False

17.Most valves use_______ to prevent leakage from the space between the stem and the bonnet.

a) o-rings
b) a liquid seal
c) a metal to metal seal
d) packing

18.Which of the following types of valve uses a flow control element that involves sliding a flat, cylindrical, or spherical surface across an orifice?

a) globe and needle valves
b) butterfly and diaphragm valves
c) gate and plug valves
d) globe and gate valves

19.Which of the following types of valve uses a flow control element that involves moving a flexible material into the flow passage?

a) diaphragm and pinch valves
b) globe and needle valves
c) gate and plug valves
d) needle and pinch valves

20.Which of the following types of valve uses a flow control element that involves moving a disc or plug into or against an orifice?

a) gate and plug valves
b) globe and gate valves
c) globe and needle valves
d) butterfly and diaphragm valves

21.Which of the following types of valve uses a flow control element that involves rotating a disc or ellipse about a shaft extending across the diameter of an orifice?

a) gate and plug valves
b) globe and gate valves
c) glove and needle valves
d) butterfly and ball valves

22.Gate Valves are not recommended for applications which:

a) require regulation and throttling of flow
b) require good sealing with little or no leakage
c) can have no resistance to flow when the valve is open
d) require the use of flanged connections

23.The _____ is the most commonly used disk within a gate valve, because of its simplicity and strength.

a) parallel disk
b) flexible wedge
c) split wedge
d) solid wedge

24.A globe valve is suitable for stopping and starting fluid flow, but not for regulating flow.

a) True
b) False

25.Which of the following is the globe valve body design that is the simplest and most common for water applications?

a. Z-body
b. X-body
c. Angle
d. Y-body

26.Which of the following is the globe valve body design that provides a remedy for the high pressure drop inherent in globe valves?

a) Z-body
b) X-body
c) Angle
d) Y-body

27.Which of the following is the globe valve body design that can be used as both a valve and a piping elbow?

a) Z-body
b) X-body
c) Angle
d) Y-body

28.Which of the following valve types has an actuator that is of the quick-acting type, requiring only a 90 deg turn of the handle to fully open or close the valve?

a) gate valve
b) globe valve
c) ball valve
d) pinch valve

29.Which of the following valve types is well suited for an application where corrosion or metal contamination of the fluid might be a problem, because the operating mechanism is completely isolated from the fluid?

a) pinch valve
b) gate valve
c) butterfly valve
d) reducing valve

30.Which of the following types of valve causes the greatest head loss when completely open?

a) ball valve
b) gate valve
c) butterfly valve
d) globe valve

31.Which of the following is a disadvantage of ball valves?

a) They are large and heavy.
b) They have high maintenance costs.
c) They have relatively poor throttling characteristics
d) They are among the most expensive of the valve types.

32.The gland of a plug valve is equivalent to the ___ of a gate or globe valve.

a) body
b) packing
c) seat
d) bonnet

33.Which type of valve has advantages over other valve designs in weight, space and cost for large valve applications?

a) butterfly valve
b) globe valve
c) diaphragm valves
d) gate valves

34.All of the following are general types of check valves EXCEPT _.

a) butterfly
b) plug
c) swing
d) tilting disc

35.Relief and safety valves prevent equipment damage by relieving accidental over-pressurization of fluid systems.

a) True
b) False

Related Articles

Fire and Gas System Interview Questions & Answers

S Bharadwaj Reddy

Disassembly of a sliding-stem Control Valve

S Bharadwaj Reddy

Observer Systems

S Bharadwaj Reddy

Radiofrequency Mass Spectrometer

S Bharadwaj Reddy

Electronic Valve positioners

S Bharadwaj Reddy

Components of Mass Spectrometer Questions & Answers

S Bharadwaj Reddy

6 comments

Athar Yazdhani Mohammed January 2, 2018 at 7:28 am

Dear Sir,

I want to Congratulate you for launching, maintaining & updating this Website, which is Providing lots of Instrumentation Knowledge & related information through different Ways on a single Platform.
Well, regarding the “Multiple Choice Questions” Block, it’s a kind request to put the answers for the Questions at the end of the Page; so that the Users get a chance to evaluate & choose the correct answer.

Finally, I would like to express gratefulness to you & your Team for the Work done.

Thank You.

Reply
S Bharadwaj Reddy January 2, 2018 at 7:31 am

Good Suggestion. Noted. Thanks

Reply
Athar Yazdhani Mohammed January 2, 2018 at 7:45 am

Dear Sir,

Well, under the “Multiple Choice Questions” Block, please put the answers for all the Questions at the end of the Page; so that, we get a chance to evaluate and choose the correct answer.

Thanks for providing lots of information on the “INSTRUMENATION” Field.

Reply
حسین April 15, 2018 at 6:15 pm

thanks reddy
this is best site for practical instrument stay 1…;))

Reply
Sharma July 18, 2018 at 4:36 pm

ANSWERS from Inst Forum

11. b- Valve nipples are small in size so they are not found in large open channel valves
12. b
13. b
14. d- They are actuators rely on input signal like 4-20mA, or 3-15psig.
15. c- bonnet is there in upward assembly supporting stem travel. They are not exposed to inlet pressure
16. a
17. c
18. c
19. a
20. a
21. d
22. c
23. c
24. false
27. angle
28. ball
29. a-they are made of rubber or synthetic material within flange.
30. b
31. c
32. a
33. a
35. true

Reply
tissa September 26, 2018 at 5:48 am

I have pneumatic control valves. This is used to gut the molasses. To control the molassas. Molasses is in the required amount of vibrations and how to maintain this standard. Honeywel control udc1500 pneumatic valve transducer (electrical pressure)What is the reason for this change? It did not exist just because it was in good shape. Give the answer.

Reply

Leave a Comment

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More