4BE3.5 U4 C6 Obj 3 EMH

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Questions and Answers

EASY What should you do if the boiler is priming or foaming?

Open the non-return valve

Turn off the boiler

Open the boiler surface blowoff valve (correct)

Check the feedwater for contamination

What should you do in case of severe priming and water hammer?

Open the non-return valve drain

Open the boiler surface blowoff valve

Turn off the boiler and close the non-return valve (correct)

Check the feedwater for contamination

How do you identify malfunctioning steam traps?

Turn off the boiler

Check the feedwater for contamination

Open the boiler surface blowoff valve

Open the steam trap test valves (correct)

What should you do if a steam trap fails to pass condensate?

Open the trap bypass to relieve condensate Signup and view all the answers

What should you do after identifying malfunctioning steam traps?

Isolate and remove the trap for repair Signup and view all the answers

What should you report to the shift engineer or chief engineer?

Sagging steam lines Signup and view all the answers

What should be done when a steam line is out of service?

Repair or replace steam traps Signup and view all the answers

Why should the boiler water level not be too high?

All of the above Signup and view all the answers

What should be done to prevent excess steam and water loss during warm-up?

Pinch off trap bypasses and steam line drains Signup and view all the answers

What should be installed in steam lines to help remove moisture from the steam?

Steam separators Signup and view all the answers

What should be checked in heating systems to prevent water hammer?

The Hartford Loop Signup and view all the answers

What should be done if water hammer or vibration occurs while the non-return valve is being opened?

Close the valve at once Signup and view all the answers

What should be done to ensure correct boiler operations?

All of the above Signup and view all the answers

What should be installed in piping systems to lessen the occurrence or severity of water hammer?

All of the above Signup and view all the answers

Why should steam lines be properly graded?

To ensure the direction of flow Signup and view all the answers

What should be done if water hammer occurs in the boiler house?

Check the boiler water level Signup and view all the answers

What is the primary symptom of water hammer?

Loud noises accompanied by piping system movement Signup and view all the answers

What causes sudden stoppage of fluid, leading to water hammer?

Manual valves are closed quickly Signup and view all the answers

What is the result of sudden fluid acceleration?

Water hammer Signup and view all the answers

How can water hammer be prevented?

By operating equipment carefully Signup and view all the answers

What is the recommended time to fully open or fully close a valve?

5 seconds per 25 mm of pipe diameter Signup and view all the answers

What should be done to prevent water hammer when shutting off a centrifugal pump?

Slowly close the discharge valve before shutting off the pump Signup and view all the answers

What is the consequence of not preventing water hammer?

Pipe failures Signup and view all the answers

Why is it imperative for operators to be familiar with methods of water hammer prevention?

To prevent pipe failures and costly damages Signup and view all the answers

MEDIUM What is the primary cause of water hammer in a steam plant?

Sudden stoppage of fluid Signup and view all the answers

What is the result of severe water hammer?

Pipe failures Signup and view all the answers

Which of the following is NOT a cause of sudden fluid acceleration?

Swing check valves closing slowly Signup and view all the answers

What is the recommended time to fully open or fully close a manual valve?

5 seconds per 25 mm of pipe diameter Signup and view all the answers

Which of the following is an operational solution to prevent water hammer?

Operating equipment carefully Signup and view all the answers

What is the effect of sudden stoppage of fluid in a steam plant?

Water hammer Signup and view all the answers

Which of the following is a characteristic of water hammer?

Series of loud noises Signup and view all the answers

What is the purpose of familiarizing operators with methods of water hammer prevention?

To prevent the consequences of water hammer Signup and view all the answers

What is the primary purpose of opening the boiler surface blowoff valve?

To remove impurities from near the boiler water surface Signup and view all the answers

What should you do first when dealing with severe priming and water hammer?

Turn off the boiler and close the non-return valve Signup and view all the answers

How do you relieve condensate from the steam system when a steam trap fails to pass condensate?

By opening the trap bypass Signup and view all the answers

What should you observe in steam lines to prevent water hammer?

Sagging, missing insulation, and broken pipe hangers Signup and view all the answers

What should you do after identifying malfunctioning steam traps?

Isolate and remove the trap for repair or replacement Signup and view all the answers

What is the correct procedure when dealing with malfunctioning steam traps?

Blow out the trap strainer, then place the trap on-line and recheck its operation Signup and view all the answers

Why is it necessary to repair or replace steam traps when a steam line is out of service?

To ensure the steam trap is functional when the steam line is returned to service Signup and view all the answers

What is the purpose of inspecting steam lines for damaged or missing insulation?

To prevent excess condensate from accumulating in areas not served by traps Signup and view all the answers

What is the reason for opening all trap bypasses and manual condensate drains during the warm-up period?

To handle the large amount of condensate that forms when equipment first warms up Signup and view all the answers

What is the consequence of not ensuring the water level is not too high in the boiler?

Foaming and priming will lead to carryover and water hammer Signup and view all the answers

What is the purpose of installing steam separators in longer saturated steam lines?

To help remove moisture from the steam Signup and view all the answers

What should be installed around steam valves on steam lines larger than DN 50?

Warm-up valves Signup and view all the answers

What is the recommended action if water hammer or vibration occurs while the non-return valve is being opened?

Close the valve at once and ensure the steam line is warm Signup and view all the answers

What is the purpose of blowing off the water column and gauge glass in the boiler house?

To ensure the water level is accurate Signup and view all the answers

What is the result of not properly grading steam lines and condensate lines?

Condensate will accumulate in areas not served by traps Signup and view all the answers

What should be done to prevent water hammer when shutting off a centrifugal pump?

Install surge arrestors downstream of pumps Signup and view all the answers

HARD What is the primary consequence of water hammer in a steam plant?

Pipe failure and costly repairs Signup and view all the answers

Which of the following is NOT a cause of sudden fluid acceleration in a steam plant?

Centrifugal pumps shutting off slowly Signup and view all the answers

What is the recommended time to fully open or fully close a manual valve on a DN 200 pipe?

40 seconds Signup and view all the answers

What is the primary purpose of operating manual valves slowly in a steam plant?

To prevent water hammer and pipe damage Signup and view all the answers

What is the result of sudden stoppage of fluid in a steam plant?

Water hammer and pipe movement Signup and view all the answers

Which of the following is an operational solution to prevent water hammer in a steam plant?

Operating equipment carefully Signup and view all the answers

What is the characteristic of water hammer in a steam plant?

Loud noises and pipe movement Signup and view all the answers

What is the purpose of familiarizing operators with methods of water hammer prevention?

To prevent water hammer and pipe damage Signup and view all the answers

What is the primary purpose of correcting the boiler water conditions when the boiler is priming or foaming?

To prevent water hammer in the plant Signup and view all the answers

What is the most effective way to locate malfunctioning steam traps in the plant?

By opening the steam trap test valves Signup and view all the answers

What is the primary reason for isolating and removing a malfunctioning steam trap from service?

To perform repairs or replacement Signup and view all the answers

What is the consequence of not following plant lockout and tagout procedures when repairing a steam trap?

The trap may not be properly isolated for repair Signup and view all the answers

What is the primary reason for observing steam lines for sagging, missing insulation, and broken pipe hangers?

To prevent water hammer in the plant Signup and view all the answers

What is the purpose of throttling the bypass valve when relieving condensate from the steam system?

To prevent excessive steam loss Signup and view all the answers

What is the primary reason for installing steam traps in steam lines?

To remove condensate that builds up when the valve cycles off Signup and view all the answers

What is the recommended action to take when admitting steam to cold steam lines?

Ensure all steam traps are in service Signup and view all the answers

What is the primary purpose of installing surge arrestors in fluid-handling systems?

To prevent sudden stoppage of fluid Signup and view all the answers

What is the consequence of not repairing or replacing steam traps when a steam line is out of service?

The steam line will not return to service properly Signup and view all the answers

What is the primary purpose of installing soft-start variable frequency drives in fluid-handling systems?

To start, modulate, and stop centrifugal pumps Signup and view all the answers

What is the recommended action to take when dealing with severe priming and water hammer?

Check the boiler water level Signup and view all the answers

What is the primary purpose of inspecting steam lines for broken or disconnected pipe hangers?

To prevent sagging pipes and condensate accumulation Signup and view all the answers

What is the recommended action to take when opening the non-return valve and water hammer or vibration occurs?

Close the non-return valve at once Signup and view all the answers

What is the primary purpose of installing warm-up valves around steam valves on steam lines larger than DN 50?

To limit the steam pressure in the cold steam line Signup and view all the answers

What is the primary purpose of ensuring steam and condensate lines are properly graded?

To prevent water hammer Signup and view all the answers

Study Notes

Identifying Water Hammer

Water hammer is recognizable by loud noises and piping system movement, ranging from small pings to loud bangs and slight to dramatic piping system movement.

Causes of Water Hammer

Sudden stoppage of fluid, caused by:
Manual valves closed quickly
Control valves (solenoid valves) closing rapidly
Swing check valves closing suddenly when pumps stop or control valves close quickly
Sudden fluid acceleration, caused by:
Pumps starting suddenly with discharge valves fully open
Manual valves opened quickly
Control valves (solenoid valves) opening rapidly
Co-existence of saturated steam and saturated water (condensate) in steam or condensate lines

Preventing Water Hammer

Operate equipment carefully
Redesign piping systems
Install piping components that reduce or eliminate water hammer

Operational Solutions

Operate manual valves slowly (5 seconds to fully open/close per 25mm pipe diameter)
For centrifugal pumps, slowly close discharge valve before shutting off the pump
For steam lines:
Repair or replace steam traps when out of service
Inspect steam lines for broken/disconnected pipe hangers and repair/replace
Inspect steam lines for damaged/missing insulation and repair/replace
Regularly clean steam trap strainers
Ensure all steam traps are in service before admitting steam to cold steam lines
Open all trap bypasses and manual condensate drains during warm-up period
Warm up steam lines using small warm-up lines, rather than main isolation valves
Allow trap bypasses or steam line drains to blow until steam lines are warmed up
Ensure correct boiler operations

Design and Equipment Solutions

Identify low points in steam lines and install appropriate steam traps
Ensure installed steam traps are of proper type and capacity
Install steam separators in longer saturated steam lines to remove moisture from steam
Ensure steam and condensate lines are properly graded
Install warm-up valves around steam valves on steam lines larger than DN 50
Ensure traps are installed in steam lines before control valves
Install soft-start variable frequency drives for centrifugal pumps
Install slow-opening solenoid valves
Install no-slam design check valves
Install surge arrestors downstream of pumps
Redesign piping systems for lower fluid velocities

Response to Water Hammer

When Placing a Boiler On-Line

If water hammer or vibration occurs while opening non-return valve, close the valve and:
Ensure steam line between header and boiler is warm
Open drains between header isolation valve and non-return valve to blow steam
Try opening non-return valve again, but more slowly

During Routine Operation

Water Hammer in the Boiler House

If water hammer occurs, immediately check boiler water level
If high water level or priming, lower water level with boiler blowoff valves
Determine cause of high water level or carryover
If boiler is priming or foaming, open boiler surface blowoff valve to remove impurities
Correct boiler water conditions causing the situation

Water Hammer in the Plant

Open steam trap test valves or use other means to locate malfunctioning steam traps
Blow out trap strainers to remove blockage
Place trap on-line and recheck operation
If trap fails to pass condensate, open trap bypass to relieve condensate
Throttle bypass valve to prevent excessive steam loss or water hammer
Isolate and remove trap for repair or replacement
Follow plant lockout and tagout procedures

Identifying Water Hammer

Water hammer is recognizable by loud noises and piping system movement, ranging from small pings to loud bangs and slight to dramatic piping system movement.

Causes of Water Hammer

Sudden stoppage of fluid, caused by:
Manual valves closed quickly
Control valves (solenoid valves) closing rapidly
Swing check valves closing suddenly when pumps stop or control valves close quickly
Sudden fluid acceleration, caused by:
Pumps starting suddenly with discharge valves fully open
Manual valves opened quickly
Control valves (solenoid valves) opening rapidly
Co-existence of saturated steam and saturated water (condensate) in steam or condensate lines

Preventing Water Hammer

Operate equipment carefully
Redesign piping systems
Install piping components that reduce or eliminate water hammer

Operational Solutions

Operate manual valves slowly (5 seconds to fully open/close per 25mm pipe diameter)
For centrifugal pumps, slowly close discharge valve before shutting off the pump
For steam lines:
Repair or replace steam traps when out of service
Inspect steam lines for broken/disconnected pipe hangers and repair/replace
Inspect steam lines for damaged/missing insulation and repair/replace
Regularly clean steam trap strainers
Ensure all steam traps are in service before admitting steam to cold steam lines
Open all trap bypasses and manual condensate drains during warm-up period
Warm up steam lines using small warm-up lines, rather than main isolation valves
Allow trap bypasses or steam line drains to blow until steam lines are warmed up
Ensure correct boiler operations

Design and Equipment Solutions

Identify low points in steam lines and install appropriate steam traps
Ensure installed steam traps are of proper type and capacity
Install steam separators in longer saturated steam lines to remove moisture from steam
Ensure steam and condensate lines are properly graded
Install warm-up valves around steam valves on steam lines larger than DN 50
Ensure traps are installed in steam lines before control valves
Install soft-start variable frequency drives for centrifugal pumps
Install slow-opening solenoid valves
Install no-slam design check valves
Install surge arrestors downstream of pumps
Redesign piping systems for lower fluid velocities

Response to Water Hammer

When Placing a Boiler On-Line

If water hammer or vibration occurs while opening non-return valve, close the valve and:
Ensure steam line between header and boiler is warm
Open drains between header isolation valve and non-return valve to blow steam
Try opening non-return valve again, but more slowly

During Routine Operation

Water Hammer in the Boiler House

If water hammer occurs, immediately check boiler water level
If high water level or priming, lower water level with boiler blowoff valves
Determine cause of high water level or carryover
If boiler is priming or foaming, open boiler surface blowoff valve to remove impurities
Correct boiler water conditions causing the situation

Water Hammer in the Plant

Open steam trap test valves or use other means to locate malfunctioning steam traps
Blow out trap strainers to remove blockage
Place trap on-line and recheck operation
If trap fails to pass condensate, open trap bypass to relieve condensate
Throttle bypass valve to prevent excessive steam loss or water hammer
Isolate and remove trap for repair or replacement
Follow plant lockout and tagout procedures

Identifying Water Hammer

Water hammer is recognizable by loud noises and piping system movement, ranging from small pings to loud bangs and slight to dramatic piping system movement.

Causes of Water Hammer

Sudden stoppage of fluid, caused by:
Manual valves closed quickly
Control valves (solenoid valves) closing rapidly
Swing check valves closing suddenly when pumps stop or control valves close quickly
Sudden fluid acceleration, caused by:
Pumps starting suddenly with discharge valves fully open
Manual valves opened quickly
Control valves (solenoid valves) opening rapidly
Co-existence of saturated steam and saturated water (condensate) in steam or condensate lines

Preventing Water Hammer

Operate equipment carefully
Redesign piping systems
Install piping components that reduce or eliminate water hammer

Operational Solutions

Operate manual valves slowly (5 seconds to fully open/close per 25mm pipe diameter)
For centrifugal pumps, slowly close discharge valve before shutting off the pump
For steam lines:
Repair or replace steam traps when out of service
Inspect steam lines for broken/disconnected pipe hangers and repair/replace
Inspect steam lines for damaged/missing insulation and repair/replace
Regularly clean steam trap strainers
Ensure all steam traps are in service before admitting steam to cold steam lines
Open all trap bypasses and manual condensate drains during warm-up period
Warm up steam lines using small warm-up lines, rather than main isolation valves
Allow trap bypasses or steam line drains to blow until steam lines are warmed up
Ensure correct boiler operations

Design and Equipment Solutions

Identify low points in steam lines and install appropriate steam traps
Ensure installed steam traps are of proper type and capacity
Install steam separators in longer saturated steam lines to remove moisture from steam
Ensure steam and condensate lines are properly graded
Install warm-up valves around steam valves on steam lines larger than DN 50
Ensure traps are installed in steam lines before control valves
Install soft-start variable frequency drives for centrifugal pumps
Install slow-opening solenoid valves
Install no-slam design check valves
Install surge arrestors downstream of pumps
Redesign piping systems for lower fluid velocities

Response to Water Hammer

When Placing a Boiler On-Line

If water hammer or vibration occurs while opening non-return valve, close the valve and:
Ensure steam line between header and boiler is warm
Open drains between header isolation valve and non-return valve to blow steam
Try opening non-return valve again, but more slowly

During Routine Operation

Water Hammer in the Boiler House

If water hammer occurs, immediately check boiler water level
If high water level or priming, lower water level with boiler blowoff valves
Determine cause of high water level or carryover
If boiler is priming or foaming, open boiler surface blowoff valve to remove impurities
Correct boiler water conditions causing the situation

Water Hammer in the Plant

Open steam trap test valves or use other means to locate malfunctioning steam traps
Blow out trap strainers to remove blockage
Place trap on-line and recheck operation
If trap fails to pass condensate, open trap bypass to relieve condensate
Throttle bypass valve to prevent excessive steam loss or water hammer
Isolate and remove trap for repair or replacement
Follow plant lockout and tagout procedures

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Description

This quiz covers the identification and causes of water hammer, including the sounds and movements associated with it, and the sudden changes in fluid flow that trigger it.