Previous in Forum: PWHT Requirement   Next in Forum: Converting Scuba Tanks into Constant Pressure Source
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
8 comments
Rate Comments: Nested
Anonymous Poster #1

Popping Up of a Spring Loaded Safety Valve

09/24/2013 10:42 AM

a new factory tested spring loaded safety valve behave erratically. When tested at site, it pops up at 0.5 bar less than the set pressure and sometimes 0.2 bar above the set pressure. The supplier says that it is ok. I there any standard which can be referred on this matter?
Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#1

Re: Popping up of a spring loaded safety valve.

09/24/2013 10:46 AM

Yep. Go to the Engineer/Surveyor for the company supplying burst indemnity insurance cover for the facility. That individual will have access to the correct standard.

Of course the supplier says it's OK! In the facility accepting it for use, the supplier can run off to the bank rejoicing!

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#2

Re: Popping Up of a Spring Loaded Safety Valve

09/24/2013 11:15 AM

Why is this plant being operated in such a way that the pressure safety valve needs to operate in the first place?

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply Score 1 for Off Topic
HiTekRedNek
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 8277
Good Answers: 270
#6
In reply to #2

Re: Popping Up of a Spring Loaded Safety Valve

09/24/2013 11:08 PM

All pressurized boilers in the USA require safety(pop-off) valves.This is like a fuse or circuit breaker in an electrical panel..for when things go wrong.

It is a good practice to test and verify all pressure safety valves before accepting them,and is required by most insurance companies before they will issue the policy.

I remember one case where a safety pin was left in a pop-off valve,and the make up water pump failed on a coal boiler.The valve,which weighed about 600 pounds,went thru the roof of the boiler room and came back down through the same hole,and knocked out the catwalk on the top level of the boiler.Fortunately, no one was hurt.The picnic scheduled for the contractor for finishing the job early was cancelled.

__________________
 "A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience" "To create an apple pie from scratch, first you must create a universe"
Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#7
In reply to #6

Re: Popping Up of a Spring Loaded Safety Valve

09/25/2013 3:58 AM

Roger that. The question was about the operation of the plant. When a safety valve lifts, process material is being dumped. The original poster needs to explain why this is being accepted as a normal occurrence, for it indicates that the plant is being driven at the operating limit with the intention to go beyond it!

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
HiTekRedNek
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 8277
Good Answers: 270
#8
In reply to #7

Re: Popping Up of a Spring Loaded Safety Valve

09/25/2013 7:20 AM

Ok, I interpreted the OP as testing the pop-off safety valve at a calibration test bench,not in an actual process.I also presumed a steam application,which I know is a very narrow interpretation.

__________________
 "A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience" "To create an apple pie from scratch, first you must create a universe"
Reply
ozzb
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 5197
Good Answers: 266
#3

Re: Popping Up of a Spring Loaded Safety Valve

09/24/2013 12:11 PM

You can not tell us it acted erratically without more information. What is the pressure that the relief valve is rated for? What was the temperature of the valve at the time the relief valve opened? Changes in temperature effect spring tension. The relief valve set pressure should be 10% above max operating pressure. The operating pressure should not be that close to this device's set pressure. Device specs depend on what it's design to protect.

__________________
 Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Reply
lyn
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#4

Re: Popping Up of a Spring Loaded Safety Valve

09/24/2013 2:13 PM

Apply this tool to the valve spring whenever it doesn't act to suit you.
Reply Score 1 for Off Topic
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#5

Re: Popping Up of a Spring Loaded Safety Valve

09/24/2013 10:23 PM

What is the nominal setting of the valve? What percentage of that is the range of -0.5/+0.2 bar? Why were these essential items omitted from the OP?

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Reply
Reply to Forum Thread
Have a Different Question?
8 comments
Copy to Clipboard

Users who posted comments:

HiTekRedNek (2); lyn (1); ozzb (1); PWSlack (3); Tornado (1)

Previous in Forum: PWHT Requirement   Next in Forum: Converting Scuba Tanks into Constant Pressure Source

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Mechanical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (72 right now)
Show Members
Advertisement