BI_4B

Question 1

How do weight loaded pressure regulators work?

Answer 1

Weight tends to open the valve, but the downstream pressure works against the weight to counter balance the downward force. Ref: p.51

Question 2

Explain the difference between a fixed orifice and a variable orifice.

Answer 2

A fixed orifice opening cannot be changed readily. A given size will pass a certain flow at a given pressure. A variable orifice can be changed at will, and is usually a needle valve. Ref: p.52-53

Question 3

Why is an air relay necessary with the flapper valve?

Answer 3

because of the time necessary to fill the actuator diaphragm due to the orifice in the supply line. Ref: p.54

Question 4

Which is not true of non-bleed relays?

a) they waste little air
b) they are reliable units
c) they are usually smaller than bleed units of similar rating
d) they have a constant loss of air from the relay unless the nozzle pack pressure is at either maximum or a minimum.

Answer 4

d) they have a constant loss of air from the relay unless the nozzle pack pressure is at either maximum or a minimum. ref: p. 62-64

Question 5

Which of the following is an orifice?

a) fixed
b) variable c) needle valve d) all of the above

Answer 5

d) all of the above ref: p. 52

Question 6

Name the five parts of a self-contained spring-loaded regulator.

Answer 6

1) set-point adjustment 2) compressed spring 3) inlet 4) outlet 5) valve plug ref: p. 52

Question 7

Pneumatic controllers for commercial applications usually are of on-off action.

a) True
b) False

Answer 7

b) false ref: p. 61

Question 8

A Booster relay is used to overcome response lag due to long connecting lines between the controller and valve

a) True
b) False

Answer 8

‘a) True ref: p. 64

Question 9

A basic pneumatic positioner uses what two things? Select all that apply (2 pts.)

a) Fixed orifice
b) auxiliary relay
c) globe
d) nozzle and diaphragm pressure
e) solenoid

Answer 9

a) Fixed orifice
d) nozzle and diaphragm pressure ref: p. 66