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SSV closing time 1
- Thread starter godel123
- Start date
LittleInch
Petroleum
By SSV I think you mean sub surface valve?
Closure should be around 15 seconds?
No more than 30.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Closure should be around 15 seconds?
No more than 30.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
-
1
- #3
georgeverghese
Chemical
SSV = surface safety valve ?
On a hydraulic actuator, time to close is much better than for an air operated valve - it also depends on the size of the return hydraulic line - if there are many SSVs' and they all close at the same time, then closing time would be slower than for a single SSV only. If you have a slow closing SSV, then one of more of the return lines or the return manifold may be the bottleneck.
On a hydraulic actuator, time to close is much better than for an air operated valve - it also depends on the size of the return hydraulic line - if there are many SSVs' and they all close at the same time, then closing time would be slower than for a single SSV only. If you have a slow closing SSV, then one of more of the return lines or the return manifold may be the bottleneck.
- Thread starter
- #4
georgeverghese
Chemical
Little Inch , Godel123
In the absence of a company standard:
For an air op SDV, typical closing speed is about 1inch to 1.5inch of nominal size per second, so would guess that for a single acting, fail close SSV, you should get approx 2inch of nominal bore per sec or better.
So, for an SSV on a 6inch line, closing time = 3sec or better.
In the absence of a company standard:
For an air op SDV, typical closing speed is about 1inch to 1.5inch of nominal size per second, so would guess that for a single acting, fail close SSV, you should get approx 2inch of nominal bore per sec or better.
So, for an SSV on a 6inch line, closing time = 3sec or better.
- Thread starter
- #6
LittleInch
Petroleum
Gödel,
Now we know valve you're talking about, no, there is no set figure AFAIK, only guidelines and perhaps company standards and targets.
The oft quoted 1 inch per second is just a guide. 50 m of tubing - closure will depend on tubing size and size of the return spring, but max time for say a 6inch valve 10 to 15 seconds. In reality most of the time it would be probably about 5 or less.
I got a 16" class 600 ball valve to close in 3 seconds to 5 seconds - needed two air ports and a BIG spring, but it did it.
Why are you asking??
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Now we know valve you're talking about, no, there is no set figure AFAIK, only guidelines and perhaps company standards and targets.
The oft quoted 1 inch per second is just a guide. 50 m of tubing - closure will depend on tubing size and size of the return spring, but max time for say a 6inch valve 10 to 15 seconds. In reality most of the time it would be probably about 5 or less.
I got a 16" class 600 ball valve to close in 3 seconds to 5 seconds - needed two air ports and a BIG spring, but it did it.
Why are you asking??
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #8
LittleInch
Petroleum
Each case is different so there is no document.
If it is safety critical that your valve shuts in 2 seconds, then you design it to shut in 2 seconds. If 10 seconds doesn't result in significant safety issues then it is more economic to design it to shut in 10 seconds (smaller tubing, smaller springs, less complex electronics etc etc). Taking 30 seconds or 60 seconds to close defeats the point of having the valve. All highly variable.
Not everything is prescribed in a standard or design code.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
If it is safety critical that your valve shuts in 2 seconds, then you design it to shut in 2 seconds. If 10 seconds doesn't result in significant safety issues then it is more economic to design it to shut in 10 seconds (smaller tubing, smaller springs, less complex electronics etc etc). Taking 30 seconds or 60 seconds to close defeats the point of having the valve. All highly variable.
Not everything is prescribed in a standard or design code.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
georgeverghese
Chemical
A 50m long return header can result in a slow closing SSV if it isnt sized correctly. Directionaly speaking, increasing return header size by 2nominal sizes up or so may give you a much better closing time. Run some pressure drop calcs on this return header with the required closing time and then you'll see where and what needs to be done.
- Thread starter
- #11
georgeverghese
Chemical
Yes, use the max oil displacement rate from the sum total of all actuators that could be activated in the pressure drop calc, and also use the max viscosity of the oil at the lowest ambient operating temp.
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- #13
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