Over tightening of the valve stem packing to...

Question 1 of 270705eccefa5bacbc34ba4d487f2

Over tightening of the valve stem packing to a pneumatically controlled final control element, shown in the illustration, will cause __________. See illustration GS-0051.

Back

Question 1 of 27070

Over tightening of the valve stem packing to a pneumatically controlled final control element, shown in the illustration, will cause __________. See illustration GS-0051.

No Illustration

This question does not have an illustration

🔍 Key Concepts

• Relationship between valve stem packing tightness and stem friction/sticking • How a pneumatic diaphragm actuator moves the stem in small, frequent adjustments to control flow • Effect of increased friction on smooth, proportional control action

💭 Think About

• Look at the stem where the packing is located in the illustration: what happens to stem movement if the packing is compressed too hard around it? • In an automatic control loop, if the stem does not move freely to match small changes in air signal, how will the valve’s motion and process variable behave? • Which option best matches the behavior of a valve that moves with stick–slip motion rather than smooth travel?

✅ Before You Answer

• Be clear on what packing actually does (sealing vs. supporting or cooling). • Ask whether over tightening packing would realistically cause immediate mechanical failure or temperature rise, or first cause a change in how smoothly the stem moves. • Choose the option that reflects increased resistance to stem motion and possible stick–slip behavior.