Can anyone share philosophy of Automatic Block Valve and emergency block valve?
What are considerations in view of piping design.?
Back in the day (before I retired) we used to call these "ESV" (Emergency Shut-Down Valves).
These were normally the standard line class block valve fitted with a rapid action motor or pneumatic operator.
The valve, the operator and the control cables were covered with fireproof insulation.
In an emergency these valves would either close or open (as required) automatically and the plant would be shut-down.
Automatic block valve can act as your first layer of protection and once
the alarm condition is reached (e.g. high level), the valve is shut by
means of a software interlock.
The emergency block valve would
act as your final layer of protection and the valve should be shut by
means of a separate hard-wired interlock.
You can have the same
valve performing both applications. e.g. A high level from a level
transmitter will shut the valve. If this instrument fails, a separate
high high level switch will shut the valve.
I have also seen an
application where the above 2 functions are performed by the same valve
by having 2 different solenoids each receiving a different signal.
Many plants use gate valves for isolating units at the battery limits
etc. Large gate valves require many turns of the handwheel to
open. Automated valves may use electric actuators to permit remote
operation. An operator may also push buttons to open or close such
valves. Usually a manual hand wheel is also provided as an override
when power is lost. Such a valve would fall into the automated
isolation valve description. Some quarter turn pneumatic valves are
also operated using a vane actuator (perhaps gas over oil with stored
energy) or double acting pneumatic actuator (perhaps with an air storage
cylinder and double check valves on the supply). Lacking a spring
these automated valves would not be suitable as emergency shutdown
valves.
A pneumatic actuator on a quarter turn ball or butterfly
valve is more common for an emergency shutdown valve. The emergency
shutdown valve should be able to close with no power or air supply.
From the originalgatevalve
.
2010年12月22日星期三
PN Designated Valves - Pressure Temperature Ratings
I am trying to determine in which standard the p/T ratings of PN
designated valves is given. Or in other words, when a valve is stated to
be PN16 Rated - to which standard is is rated as such?
I am
aware of BS EN standards that cover the face to face dimensions etc. but
I cannot seem to find anything that allows you to look up the material,
class, temperature and the corresponding pressure rating for any given
PN designation. (Like one does with the tables in ASME B16.5).
I
am aware that EN1092-1 covers the p/T ratings of the flanges. Do these
extend automatically to the valve as the valve body and components are
assumed to be always stronger than the flanges?
Or is there some other theory behind the determination of a PN designated valves p/T rating?
You don't say where you are from, but from the nomenclature, it appears
you are talking about European (CE)specs? The CE Pressure Equipment
Directive is 97/23/EN (google on those terms, you should be able to find
a copy of this from the CE servers, in the language of your
choice). The PED has tables that specify the pressure and temperature
limits for a part to fall within a particular classification. Moreover,
the manufacturer is supposed to maintain the certification, which
should include the details of the calculations done to show
certification, as well as the temperature and pressure limits defined
for the part, in order to comply with the PED.
Hope that helps. Though, being from the wrong side of the pond, it probably doesn't.
I am working out of the UK - I am currently writing up valve and piping specifications.
Using
the ASME system in this regard is A LOT simpler in that one can simply
state - Class 150# as per ASME B16.5 Table 2..... etc. when specifying a
valve. Proof of compliance with this is then up to the manufacturer.
Also ensuring that you are specifying something that meets both the
pressure and temperature conditions you require is then taken care of.
Most
of the components that I am specifying fall into Class 0 of the PED
with a limited number falling into Class I. In other words they only
require sound engineering practice in terms of their design - with those
in Class I not requiring a CE marking as far as I understand.
So if I understand you correctly what you are saying is:
Ensuring
p/T compliance using the EN 'method' would then require specification
of a nominal rating of PN16 (for example) and going out, finding
products that comply with this spec. Then requesting p/T curves for the
product/s and ensuring that the product meets the worst case scenario
(WCS) for p/T that you are trying to cater for. Alternatively you could
state what your WCS is then go out on enquiry with that p/T information -
which means that you may end up getting a valve with a nominal pressure
rating of PN40 in order to meet the pressure requirements at elevated
temperature.
Either method requires the PN rating to be updated on
the datasheet based on the limitations of the final chosen product -
unless you get it right first time; with the first requiring
considerably more work in terms of picking the final chosen product.
Now
- before I look like one of the guys on these forums trying to get a
quick and easy solution - I am not trying to get out of doing the work
by any means - my basic problem is trying to figure out the industry
standard way of specifying the pressure rating of valves to EN
specifications so that I can ensure I get the same thing every time with
minimal trawling through the limitless number of valves available out
there.
From the originalgatevalve
.
designated valves is given. Or in other words, when a valve is stated to
be PN16 Rated - to which standard is is rated as such?
I am
aware of BS EN standards that cover the face to face dimensions etc. but
I cannot seem to find anything that allows you to look up the material,
class, temperature and the corresponding pressure rating for any given
PN designation. (Like one does with the tables in ASME B16.5).
I
am aware that EN1092-1 covers the p/T ratings of the flanges. Do these
extend automatically to the valve as the valve body and components are
assumed to be always stronger than the flanges?
Or is there some other theory behind the determination of a PN designated valves p/T rating?
You don't say where you are from, but from the nomenclature, it appears
you are talking about European (CE)specs? The CE Pressure Equipment
Directive is 97/23/EN (google on those terms, you should be able to find
a copy of this from the CE servers, in the language of your
choice). The PED has tables that specify the pressure and temperature
limits for a part to fall within a particular classification. Moreover,
the manufacturer is supposed to maintain the certification, which
should include the details of the calculations done to show
certification, as well as the temperature and pressure limits defined
for the part, in order to comply with the PED.
Hope that helps. Though, being from the wrong side of the pond, it probably doesn't.
I am working out of the UK - I am currently writing up valve and piping specifications.
Using
the ASME system in this regard is A LOT simpler in that one can simply
state - Class 150# as per ASME B16.5 Table 2..... etc. when specifying a
valve. Proof of compliance with this is then up to the manufacturer.
Also ensuring that you are specifying something that meets both the
pressure and temperature conditions you require is then taken care of.
Most
of the components that I am specifying fall into Class 0 of the PED
with a limited number falling into Class I. In other words they only
require sound engineering practice in terms of their design - with those
in Class I not requiring a CE marking as far as I understand.
So if I understand you correctly what you are saying is:
Ensuring
p/T compliance using the EN 'method' would then require specification
of a nominal rating of PN16 (for example) and going out, finding
products that comply with this spec. Then requesting p/T curves for the
product/s and ensuring that the product meets the worst case scenario
(WCS) for p/T that you are trying to cater for. Alternatively you could
state what your WCS is then go out on enquiry with that p/T information -
which means that you may end up getting a valve with a nominal pressure
rating of PN40 in order to meet the pressure requirements at elevated
temperature.
Either method requires the PN rating to be updated on
the datasheet based on the limitations of the final chosen product -
unless you get it right first time; with the first requiring
considerably more work in terms of picking the final chosen product.
Now
- before I look like one of the guys on these forums trying to get a
quick and easy solution - I am not trying to get out of doing the work
by any means - my basic problem is trying to figure out the industry
standard way of specifying the pressure rating of valves to EN
specifications so that I can ensure I get the same thing every time with
minimal trawling through the limitless number of valves available out
there.
From the originalgatevalve
.
SPCC Containment Stormwater Discharge
I am reviewing the retrofitting of remote electrical transformer
substations for compliance with the SPCC rules and have a couple of
questions. First, containment structures for new transformers are
easily built during the station construction, but for retrofitting – a
complete concrete structure is not practical. I am aware of options
presented in 112.7(c), but what seems to be the precedent in the utility
industry? Concrete curbing?
Secondly, in the regulations “Section
by Section Analysis”, in 112.8(b)(2) – EPA says ”This rule does not
preclude innovative devices..” regarding the use of imbiber beads, or
assumingly chemical check valves, for discharging accumulated stormwater
from containment structures. It is the manufactures opinion that
chemical check-valves can be used to passively discharge accumulated
stormwater from containment structures, but the rules specially state
that “you must inspect and may drain accumulated stormwater” and keep
adequate records of that event, which is not feasible using these
passive drainage devises. Bottom line, it seems that EPA is saying that
you can install the innovative devise, but you must operate it like a
manual open/close valve. The valve manufactures say they are selling
the valves for SPCC compliance but that seems contrary to what the regs
allow, unless, the users are proposing this under the exception portion
of the rule. Any thoughts?
/////////////////////////////////////////
Both for new installations and for retrofitting we attach a liner to the
transformer pad. The liners drain to gravity oil separation tanks.
The
requirement for manual valves is waived if water is directed to a
wastewater treatment facility. But what other treatment is needed for
oil contaminated water other than oil removal. I guess I would suggest
that the chemical check valve itself constitutes the treatment facility.
Anyone buying?
From the originalgatevalve
.
substations for compliance with the SPCC rules and have a couple of
questions. First, containment structures for new transformers are
easily built during the station construction, but for retrofitting – a
complete concrete structure is not practical. I am aware of options
presented in 112.7(c), but what seems to be the precedent in the utility
industry? Concrete curbing?
Secondly, in the regulations “Section
by Section Analysis”, in 112.8(b)(2) – EPA says ”This rule does not
preclude innovative devices..” regarding the use of imbiber beads, or
assumingly chemical check valves, for discharging accumulated stormwater
from containment structures. It is the manufactures opinion that
chemical check-valves can be used to passively discharge accumulated
stormwater from containment structures, but the rules specially state
that “you must inspect and may drain accumulated stormwater” and keep
adequate records of that event, which is not feasible using these
passive drainage devises. Bottom line, it seems that EPA is saying that
you can install the innovative devise, but you must operate it like a
manual open/close valve. The valve manufactures say they are selling
the valves for SPCC compliance but that seems contrary to what the regs
allow, unless, the users are proposing this under the exception portion
of the rule. Any thoughts?
/////////////////////////////////////////
Both for new installations and for retrofitting we attach a liner to the
transformer pad. The liners drain to gravity oil separation tanks.
The
requirement for manual valves is waived if water is directed to a
wastewater treatment facility. But what other treatment is needed for
oil contaminated water other than oil removal. I guess I would suggest
that the chemical check valve itself constitutes the treatment facility.
Anyone buying?
From the originalgatevalve
.
Is there a Difference?
I’m an engineer at a power plant 1 hour north of Baltimore. I was visiting your site and had a pump question. My plant has 2 single stage liquid ring pumps. They are rated for 30 scfm (we remove 6 - 8 scfm) and they have a hogging capacity of 700 scfm. We have had our vacuum pumps fails 3 times in ten years. Twice the impellors have broken. Once the impellor ripped through the pump casing; fortunately know one was injury. A bad weld job was identified was the cause of one failure and cavitations was the other cause. Currently, because of the water temperature, we are forced to run with both vacuum pumps. We are looking to possibly purchasing another pump; however we need to identify the right pump for our plant. Our vacuum pumps are more or less meant to be hogging pumps (I think). We believe that our pumps are sized correctly, however one theory we have is that hogging vacuum pumps are not normally designed for continuous use; therefore our pumps have a short life span and that we should switch to two stage pumps. Is there any truth to this?
It sounds like your pumps could be oversized, which is not a good thing
for a liquid ring pump. If it cannot suck enough gas the pressure will
go down and you can get cavitation. Your high water temperatures would
make the situation worse. I have also seen impellers come apart under
these circumstances.
It would be helpful if you could describe
the control system as this is another area where it is easy to go wrong.
I have found the technical reps from the suppliers to be very helpful
and knowledgeable and you should get their advice.
What is hogging? Peak load? If so, how can a 30scfm pump take 700scfm?
30scfm
pumps are very small and generally there shouldn't be any problem.
However, you can have a look into the following things, if it is a water
ring pump.
1. Casing should be totally drained before starting
the pump and you should let in water as soon as the pump starts. These
things can be accomplished by a automatic casing drain valve (just like a
check valve) and an automatic valve in the sealing liquid line.
2. Check for casing clearances.
3. Check the teflon balls of the discharge and suction valves. They might have got struck to their seats.
4.
Finally, check your maintenance records. If you hadn't touched them
except when they broke down, 3 times in 10 years is not unusual.
From the originalgatevalve
.
It sounds like your pumps could be oversized, which is not a good thing
for a liquid ring pump. If it cannot suck enough gas the pressure will
go down and you can get cavitation. Your high water temperatures would
make the situation worse. I have also seen impellers come apart under
these circumstances.
It would be helpful if you could describe
the control system as this is another area where it is easy to go wrong.
I have found the technical reps from the suppliers to be very helpful
and knowledgeable and you should get their advice.
What is hogging? Peak load? If so, how can a 30scfm pump take 700scfm?
30scfm
pumps are very small and generally there shouldn't be any problem.
However, you can have a look into the following things, if it is a water
ring pump.
1. Casing should be totally drained before starting
the pump and you should let in water as soon as the pump starts. These
things can be accomplished by a automatic casing drain valve (just like a
check valve) and an automatic valve in the sealing liquid line.
2. Check for casing clearances.
3. Check the teflon balls of the discharge and suction valves. They might have got struck to their seats.
4.
Finally, check your maintenance records. If you hadn't touched them
except when they broke down, 3 times in 10 years is not unusual.
From the originalgatevalve
.
Universal Piping Flanges
Could anyone provide information or a source for "universal pipe flanges"?
There are called Socket-Weld and Slip-On flanges. Pipe schedule is immaterial, and makes the flanges "universal".
I think, if you check the exact bolt hole dimensions on ANSI and DIN
flanges, you will find that they can be bolted together face to face,
with the exception of some 2" flanges where bolt clearence becomes
tight, but I think that even though tight, the bolts can still be
inserted. Check the exact dimensions of the specific case you have
before making any special spools.
Gator, It's probably going to be a situation where the flanges are at a unit or plant
limit that also comes with a code break at the same place, which is
common when connecting between European and American companies in
various parts of the world where there is no national requirement and
one code is thought to be just as good as the next. As long as you used
A code, it was legal. I've
even had requirements for DIN on the pump stations and ANSI on the
pipelines when connecting between defense ministry and national oil
company facilities.
6" and 8" are about the only sizes where you might be able to bolt a
150# flange to a PN10/PN16 flange with a full sized bolt (and a
mallet). You may be able to get some of the smaller flanges together
using undersized bolts, but that would be a sure code violation. At 3" a
150# flange has 4 bolt holes while the DIN PN10 flange has 8.
Apart
from the problem of bolting the flanges together, there is the problem
of wafer type fittings like butterfly valves and disk check valves
trying to fit inside differing bolt circles. Mixed standards are by no
means rare here in South Africa, and it can be a nightmare if it is not
very carefully managed.
My advice - forget about universal flanges and just do it properly.
From the originalgatevalve
.
There are called Socket-Weld and Slip-On flanges. Pipe schedule is immaterial, and makes the flanges "universal".
I think, if you check the exact bolt hole dimensions on ANSI and DIN
flanges, you will find that they can be bolted together face to face,
with the exception of some 2" flanges where bolt clearence becomes
tight, but I think that even though tight, the bolts can still be
inserted. Check the exact dimensions of the specific case you have
before making any special spools.
Gator, It's probably going to be a situation where the flanges are at a unit or plant
limit that also comes with a code break at the same place, which is
common when connecting between European and American companies in
various parts of the world where there is no national requirement and
one code is thought to be just as good as the next. As long as you used
A code, it was legal. I've
even had requirements for DIN on the pump stations and ANSI on the
pipelines when connecting between defense ministry and national oil
company facilities.
6" and 8" are about the only sizes where you might be able to bolt a
150# flange to a PN10/PN16 flange with a full sized bolt (and a
mallet). You may be able to get some of the smaller flanges together
using undersized bolts, but that would be a sure code violation. At 3" a
150# flange has 4 bolt holes while the DIN PN10 flange has 8.
Apart
from the problem of bolting the flanges together, there is the problem
of wafer type fittings like butterfly valves and disk check valves
trying to fit inside differing bolt circles. Mixed standards are by no
means rare here in South Africa, and it can be a nightmare if it is not
very carefully managed.
My advice - forget about universal flanges and just do it properly.
From the originalgatevalve
.
Depressuring Valves to avoid BLEVE during a Fire
What should be the air fail action for depressuring valves installed, or
nominated, to avoid a BLEVE when fire surrounds a pressure vessel?
If air fail closed, and if fire also causes damage to air system then depressuring will not happen and BLEVE possible.
If
air fail open, then vessel depressurizes when there is no fire and at a
far higher frequency than fire, leading to undesired/ unacceptable
release of organics.
As a rider to the general problem above, we
have, in the past, nominated certain PCVs to also serve as depressuring
valves. These PCVs tend to have air fail closed actions. Are there any
comments on this state of affairs?
///////////////////////////////////////////////
This is a very common problme/ question. I used to work on the
design of a NGL plant and there we had the same discussions again and
both arguments are true. But I guess that one would certainly want to
have the Blow down valves be opened during a fire event. So I tend to
make them Air FAil open. But I will then make sure that I have a
relibale source of Air that doesn't fail every now and then.
Other thing is to look for a similar design that your company has with other systems.
I don't think that there is any one answer that is correct for all
situations. As the others have indicated I think the typical action
would be depressuring valves fail open and shutdown valves fail closed
but that does not have to be so in every case.
I believe what you
are doing is the correct way to approach the problem and you need to
evaluate the advantages and disadvantages of your options. Pick the
fail position that makes the most sense for your system but expand your
evaluation to more than just the fail action of the depressuring valve.
I
can't offer any thorough reference for depressuring systems but API
RP-521 does have a little information that you may want to
review. Basically, the key points they make include...
"The valves should remain operable for the duration of the emergency or should fail in a full open position."
I
would put the emphasis on the "or" and don't necessarily interpret that
to mean that all depressuring systems should fail open.
API 521 goes on to say...
"Fireproofing of the power supply and valve actuator may be required in a fire zone."
So there are other factors that should be part of your design that should affect your decision.
For
example, I have seen emergency air supplies (small pressurized
containers) sufficient to actuate an air operated valve located close
connected with valve(API Cast Steel Valves). Maybe you could locate your depressuring valve
outside the fire zone or maybe install redundant valves. A fusible link
sounds interesting, some relief systems on compressed gas cylinders
include a combination rupture disc and fusible plug to ensure release
only during a fire event. What about depressuring your system to some
type of disposal system (flare or scrubber).
I happened to find
this article on the Instrument Society's website that talks about using a
Safety Integrity Level (SIL) selection method relating to depressuring
of a hydrocracker reactor. You might want to consider using an approach
like this to help decide which fail action is best for your system.
From the originalgatevalve
.
nominated, to avoid a BLEVE when fire surrounds a pressure vessel?
If air fail closed, and if fire also causes damage to air system then depressuring will not happen and BLEVE possible.
If
air fail open, then vessel depressurizes when there is no fire and at a
far higher frequency than fire, leading to undesired/ unacceptable
release of organics.
As a rider to the general problem above, we
have, in the past, nominated certain PCVs to also serve as depressuring
valves. These PCVs tend to have air fail closed actions. Are there any
comments on this state of affairs?
///////////////////////////////////////////////
This is a very common problme/ question. I used to work on the
design of a NGL plant and there we had the same discussions again and
both arguments are true. But I guess that one would certainly want to
have the Blow down valves be opened during a fire event. So I tend to
make them Air FAil open. But I will then make sure that I have a
relibale source of Air that doesn't fail every now and then.
Other thing is to look for a similar design that your company has with other systems.
I don't think that there is any one answer that is correct for all
situations. As the others have indicated I think the typical action
would be depressuring valves fail open and shutdown valves fail closed
but that does not have to be so in every case.
I believe what you
are doing is the correct way to approach the problem and you need to
evaluate the advantages and disadvantages of your options. Pick the
fail position that makes the most sense for your system but expand your
evaluation to more than just the fail action of the depressuring valve.
I
can't offer any thorough reference for depressuring systems but API
RP-521 does have a little information that you may want to
review. Basically, the key points they make include...
"The valves should remain operable for the duration of the emergency or should fail in a full open position."
I
would put the emphasis on the "or" and don't necessarily interpret that
to mean that all depressuring systems should fail open.
API 521 goes on to say...
"Fireproofing of the power supply and valve actuator may be required in a fire zone."
So there are other factors that should be part of your design that should affect your decision.
For
example, I have seen emergency air supplies (small pressurized
containers) sufficient to actuate an air operated valve located close
connected with valve(API Cast Steel Valves). Maybe you could locate your depressuring valve
outside the fire zone or maybe install redundant valves. A fusible link
sounds interesting, some relief systems on compressed gas cylinders
include a combination rupture disc and fusible plug to ensure release
only during a fire event. What about depressuring your system to some
type of disposal system (flare or scrubber).
I happened to find
this article on the Instrument Society's website that talks about using a
Safety Integrity Level (SIL) selection method relating to depressuring
of a hydrocracker reactor. You might want to consider using an approach
like this to help decide which fail action is best for your system.
From the originalgatevalve
.
2010年12月14日星期二
Replacing gate valve with proper seacock
On the left is a shot of the original thru-hull for my shower sump. It has a bronze thru hull with a gate valve. It is situated above the waterline unless you’re on a port tack then it’s well underwater. I don’t think it’s not up to code, but it made me squeamish so I am replacing it with a marelon thru hull and ball valve seacock.
There’s a great video on YouTube from Forespar about how to mount Marelon seacocks which I posted previously. I am basically following those exact steps.
1. I removed the old hose from the barb, the valve from the thru hull and the thru hull from the boat.
2. I then prepped the inside of the hull by sanding it down to clean fiberglass with a 4” Ryobi angle grinder.
3. I prepared a 1/2” marine grade plywood backing plate by cutting the wood and coating it with West Systems epoxy. This will be an upgrade over the original installation which has no backing plate.
4. Next I dry fit everything to make sure it would all fit together and be able to be tightened adequately.
From the originalGate Valve
.
There’s a great video on YouTube from Forespar about how to mount Marelon seacocks which I posted previously. I am basically following those exact steps.
1. I removed the old hose from the barb, the valve from the thru hull and the thru hull from the boat.
2. I then prepped the inside of the hull by sanding it down to clean fiberglass with a 4” Ryobi angle grinder.
3. I prepared a 1/2” marine grade plywood backing plate by cutting the wood and coating it with West Systems epoxy. This will be an upgrade over the original installation which has no backing plate.
4. Next I dry fit everything to make sure it would all fit together and be able to be tightened adequately.
From the originalGate Valve
.
Adequate safety precautions
After discussing the goal and safety issues with the facilities man, the plan was set:
The goal was to clear obstructions and pry open or even remove the mud gate
The first dive would be non-tethered and would be to evaluate and photograph the mud gate and determine what tools to bring on the subsequent tethered dive
On the second dive, I would wear a polypropylene rope tether and have a line tender
The tether would be secured on shore at a length that would limit my proximity to the mud gate opening- it would allow my hands to reach the area of differential pressure, but not allow my body to be sucked onto the opening
After opening the mud gate, the diver would exit the water while the impoundment drained
I geared up and then climbed down a ladder to get to the water's edge. Up close, the water still looked dark and murky and the scattered layer of foam on the surface gave it a pretty crappy look. Once I submerged, it turned out to have surprisingly good vis of about 10'! I was in my drysuit and the 64-degree water felt great!
Taking pictures along the way, a few fin kicks brought me down the sloped, mostly sandy bottom to the mud gate valve. There was a faint rumble of moving water. Large sheets of thick plastic were sucked into a slightly open corner of the gate. The plastic was also wrapped around the vertical shaft of the gate.
From the originalGate Valve
.
The goal was to clear obstructions and pry open or even remove the mud gate
The first dive would be non-tethered and would be to evaluate and photograph the mud gate and determine what tools to bring on the subsequent tethered dive
On the second dive, I would wear a polypropylene rope tether and have a line tender
The tether would be secured on shore at a length that would limit my proximity to the mud gate opening- it would allow my hands to reach the area of differential pressure, but not allow my body to be sucked onto the opening
After opening the mud gate, the diver would exit the water while the impoundment drained
I geared up and then climbed down a ladder to get to the water's edge. Up close, the water still looked dark and murky and the scattered layer of foam on the surface gave it a pretty crappy look. Once I submerged, it turned out to have surprisingly good vis of about 10'! I was in my drysuit and the 64-degree water felt great!
Taking pictures along the way, a few fin kicks brought me down the sloped, mostly sandy bottom to the mud gate valve. There was a faint rumble of moving water. Large sheets of thick plastic were sucked into a slightly open corner of the gate. The plastic was also wrapped around the vertical shaft of the gate.
From the originalGate Valve
.
What is this thing on a deaerator?
I was on a job site last week where we got convinced to supply a deaerator, which is not normally part of our scope. So, I have very little knowledge of deaerators and their valve requirements and such.
Anyway, the company in charge of doing all the piping has installed this thing (see attached) on our DA and I have no idea what it is. Can someone tell me what it is and what its purpose is?
the last item on the line going into the valve on the end nearest the
picture taker looks like a check valve, so I'd support the chemical
injection point.
Definitely not a hot tap by any definition of hot tap that I've ever
used. Though I have seen hot taps on vessels before, this just doesn't
look like one nor does the description in the OP give any indication
that it was installed on the run.
Having worked for RCS for 17 years, this is definitely not a corrosion
coupon "retractable" holder. Looking at the end, it appears this might
be a check valve. If it is, this is for injection purposes. If you
look into the end and see pins for an electrical connection, then this
is a corrosion probe, though not likely. Usually, chemical injection
quills have valves at the end to shut off the system and isolate it
while not being used. This was inserted and fixed so it is not
retractable, but adjustable is more like it.
From the originalGate Valve
.
Anyway, the company in charge of doing all the piping has installed this thing (see attached) on our DA and I have no idea what it is. Can someone tell me what it is and what its purpose is?
the last item on the line going into the valve on the end nearest the
picture taker looks like a check valve, so I'd support the chemical
injection point.
Definitely not a hot tap by any definition of hot tap that I've ever
used. Though I have seen hot taps on vessels before, this just doesn't
look like one nor does the description in the OP give any indication
that it was installed on the run.
Having worked for RCS for 17 years, this is definitely not a corrosion
coupon "retractable" holder. Looking at the end, it appears this might
be a check valve. If it is, this is for injection purposes. If you
look into the end and see pins for an electrical connection, then this
is a corrosion probe, though not likely. Usually, chemical injection
quills have valves at the end to shut off the system and isolate it
while not being used. This was inserted and fixed so it is not
retractable, but adjustable is more like it.
From the originalGate Valve
.
OHC valve lash adjuster bleeding?
Does anyone know how hydraulic lash adjusters bleed the air out of themselves? The type i'm specifially asking about in this case reside in the head. The rocker arm sits between the lash adjuster and the valve stem, with the cam pushing down on it. Chrysler 2.2 and the Mitsubishi 4G63 are two examples that come to mind.
I know that there is a ball and sproing check valve inside, and that pushing a small wire down the hole inteh top will unseat the ball, allowing you to compress the lifter. I had to do this today as i put in a new set of cams in my 4G63. After 10 minutes of idling at 1500 rpm the liters were still ticking.
HLAs constantly leak around the edges of the piston (this is a necessary
part of their function) and I would expect air bubbles to escape via
this path if the piston is facing up. If the piston isn't up, I'm not
sure how air bubbles could get out, because the body is usually a single
solid piece.
Many hydraulic valve lifters have specific storage and installation
instructions for the the lifters to allow them to initially bleed down
properly prior to initial engine start. I'm not familiar with your
specific engine but did you check the factory service manual for any
installation specifics?
Usually after the oil gets good and hot
and up to full pressure for several minutes at normal operating rpm's
they self bleed. I've not found it to be the case but others have
reported that an oil change with a new oil filter and multi weight oil
tends to quiet them down a little faster after replacement. The
viscosity of fresh multi weight oils
tends to be at its lowest point when new so that would make sense.
It's
kind of funny but in my water cooled inline 4/5 cylinder VW's and Audis
with hyrdraulic lifters, I can tell with great accuracy if the oil is
below full by any amount depending how much the lifters clatter on cold
start.
From the originalGate Valve
.
I know that there is a ball and sproing check valve inside, and that pushing a small wire down the hole inteh top will unseat the ball, allowing you to compress the lifter. I had to do this today as i put in a new set of cams in my 4G63. After 10 minutes of idling at 1500 rpm the liters were still ticking.
HLAs constantly leak around the edges of the piston (this is a necessary
part of their function) and I would expect air bubbles to escape via
this path if the piston is facing up. If the piston isn't up, I'm not
sure how air bubbles could get out, because the body is usually a single
solid piece.
Many hydraulic valve lifters have specific storage and installation
instructions for the the lifters to allow them to initially bleed down
properly prior to initial engine start. I'm not familiar with your
specific engine but did you check the factory service manual for any
installation specifics?
Usually after the oil gets good and hot
and up to full pressure for several minutes at normal operating rpm's
they self bleed. I've not found it to be the case but others have
reported that an oil change with a new oil filter and multi weight oil
tends to quiet them down a little faster after replacement. The
viscosity of fresh multi weight oils
tends to be at its lowest point when new so that would make sense.
It's
kind of funny but in my water cooled inline 4/5 cylinder VW's and Audis
with hyrdraulic lifters, I can tell with great accuracy if the oil is
below full by any amount depending how much the lifters clatter on cold
start.
From the originalGate Valve
.
Flow rate of N2 with know pressure
I am trying to figure out the flow rate of nitrogen through a 1" line. I have a high pressure (40 lb) nitrogen flowing in a 1" line. Can anyone direct me in finding charts that would correlate pressure of a certain line size with expected N2 flow rate. Or perhaps guidance into pressure and flow rate realtionships.
Here is what I basically did already...but i'm not sure if I am correct, the flow seems a bit too low ??!
Line Diameter : 1 " (.0254 m)
Line Length : 934 " (28 m)
Volume = L*A = 934*.25*pi*(.0254^2)=.012 m^3
using the Ideal Gas Law :
Mass(kg)
Press (Pa)=40 psi *6894.757 Pa/PSI = 275790.3 Pa
Volume (m^3)=.012
R (Pa.m^3/Kg.mol.K) = 8314.3
T (ambient)(K)= 298
M (Molec. Weight) (Kg/Kg.mol)=28.0134
Mass=[(press*Volume)/(R*T)]*M)=.037 kg
Once I have my Mass, since I don't have two pressures because this 40 lb pressure is constant than can I assume that my mass flowrate to be the mass that I calculated per second ?
if so then it would be .037 Kg/s
and then I would divide this by my density= 1.185 kg/m^3 (at at 1 bar 15 deg C)and this will give me my Volumetric Flow Rate of 0.032 m^3/s
Can anyone tell me if I am doing this accurately or if I am making some mistakes...I am actually a mechanical engineer and havn't had too much experience with the ideal gas law.
Assuming your pressure is absolute pressure, you seem to have calculated
the mass of N2 in the line successfully. This has no relationship to
the flow however. As you say you have no pressure drop, you actually
imply that there is no flow.
It might help to say what your line
goes to and/or where it comes from. Is it flowing freely to the air?
Does it feed a piece of equipment running at 40psia? Does it feed a
regulator? Is this the branch line off a header?
I think it is
cool that mechanical engineers can get some simple help like this in the
forum, but you must provide a little more detail. Best of luck, sshep
p.s. most engineers in this forum wouldn't consider 40 psia very high pressure.
Compressible flow problems can be complex and very frustrating. Is
it isothermal flow, or is it adiabatic flow? Which one of these two
“models” is my “real world” problem closest to? Is the flow subsonic,
choked (sonic), or supersonic?
From my interpretation of what you
wrote and did (calculation wise), I can see you need lots of help on
this particular problem. My first advice to you is get someone there
that knows chemical process engineering to help you. If that is not
possible, then I have a lot of questions to ask in order to help you:
What schedule is the 1” pipe? We are after the inside diameter.
On
the upstream end of the 1” line, what is the 1” line connected
to? Does it tee into a larger nitrogen supply header at 40 psia? Is it
connected to a pressure vessel with nitrogen at 40 psia? For the
purposes of this problem, can it be considered an unlimited supply of
nitrogen, or is it a standard cylinder of nitrogen going through a
regulator connected to the 1” line? In short, what’s the source of the
nitrogen?
How long is the 1” line? You said 934 inches, which is 23.7 meters, not 28 meters.
What
type of fittings are in the 1” line and how many are they? How many
valves are in the 1” line? What types and what size? How many 90
degree elbows are in the 1” line? How many 45 degree elbows are in the
1” line? Are there any Y-type strainers in the 1” line? Is there a
control valve in the 1” line? What size? What type? What’s the
Cv? Are there any branch-run tees in the 1” line? Are there any
line-run tees in the 1” line? Is there a check valve in the 1”
line? Is there any other fittings in the 1” line? Describe the
connection of the 1” line to the neutralizer column. Does it go into
the column below the liquid surface, or into the vapor space?
Is the 1” line insulated?
Are
there any controls in place that regulate the flow of nitrogen in the
1” line or downstream of the 1” line? I don’t know your process, but
nitrogen is not inexpensive, and I find it hard to believe that a
neutralization column would need a large flow of nitrogen all the time,
unless it was also being used as a stripper.
From the originalGate Valve
.
Here is what I basically did already...but i'm not sure if I am correct, the flow seems a bit too low ??!
Line Diameter : 1 " (.0254 m)
Line Length : 934 " (28 m)
Volume = L*A = 934*.25*pi*(.0254^2)=.012 m^3
using the Ideal Gas Law :
Mass(kg)
Press (Pa)=40 psi *6894.757 Pa/PSI = 275790.3 Pa
Volume (m^3)=.012
R (Pa.m^3/Kg.mol.K) = 8314.3
T (ambient)(K)= 298
M (Molec. Weight) (Kg/Kg.mol)=28.0134
Mass=[(press*Volume)/(R*T)]*M)=.037 kg
Once I have my Mass, since I don't have two pressures because this 40 lb pressure is constant than can I assume that my mass flowrate to be the mass that I calculated per second ?
if so then it would be .037 Kg/s
and then I would divide this by my density= 1.185 kg/m^3 (at at 1 bar 15 deg C)and this will give me my Volumetric Flow Rate of 0.032 m^3/s
Can anyone tell me if I am doing this accurately or if I am making some mistakes...I am actually a mechanical engineer and havn't had too much experience with the ideal gas law.
Assuming your pressure is absolute pressure, you seem to have calculated
the mass of N2 in the line successfully. This has no relationship to
the flow however. As you say you have no pressure drop, you actually
imply that there is no flow.
It might help to say what your line
goes to and/or where it comes from. Is it flowing freely to the air?
Does it feed a piece of equipment running at 40psia? Does it feed a
regulator? Is this the branch line off a header?
I think it is
cool that mechanical engineers can get some simple help like this in the
forum, but you must provide a little more detail. Best of luck, sshep
p.s. most engineers in this forum wouldn't consider 40 psia very high pressure.
Compressible flow problems can be complex and very frustrating. Is
it isothermal flow, or is it adiabatic flow? Which one of these two
“models” is my “real world” problem closest to? Is the flow subsonic,
choked (sonic), or supersonic?
From my interpretation of what you
wrote and did (calculation wise), I can see you need lots of help on
this particular problem. My first advice to you is get someone there
that knows chemical process engineering to help you. If that is not
possible, then I have a lot of questions to ask in order to help you:
What schedule is the 1” pipe? We are after the inside diameter.
On
the upstream end of the 1” line, what is the 1” line connected
to? Does it tee into a larger nitrogen supply header at 40 psia? Is it
connected to a pressure vessel with nitrogen at 40 psia? For the
purposes of this problem, can it be considered an unlimited supply of
nitrogen, or is it a standard cylinder of nitrogen going through a
regulator connected to the 1” line? In short, what’s the source of the
nitrogen?
How long is the 1” line? You said 934 inches, which is 23.7 meters, not 28 meters.
What
type of fittings are in the 1” line and how many are they? How many
valves are in the 1” line? What types and what size? How many 90
degree elbows are in the 1” line? How many 45 degree elbows are in the
1” line? Are there any Y-type strainers in the 1” line? Is there a
control valve in the 1” line? What size? What type? What’s the
Cv? Are there any branch-run tees in the 1” line? Are there any
line-run tees in the 1” line? Is there a check valve in the 1”
line? Is there any other fittings in the 1” line? Describe the
connection of the 1” line to the neutralizer column. Does it go into
the column below the liquid surface, or into the vapor space?
Is the 1” line insulated?
Are
there any controls in place that regulate the flow of nitrogen in the
1” line or downstream of the 1” line? I don’t know your process, but
nitrogen is not inexpensive, and I find it hard to believe that a
neutralization column would need a large flow of nitrogen all the time,
unless it was also being used as a stripper.
From the originalGate Valve
.
2010年12月9日星期四
Stop Valve
A stop valve is any sort of valve system that totally stops the flow of liquid through a pipe. There are many styles of stop valves, but two of the most common are gate valves and globe valves. Gate valves dont restrict flow when not in use, but they take longer to move into position and are more likely to leak. A globe valve will interrupt flow at all times, but will move into position very quickly. Both of these valve types are common on piping systems of all shapes and sizes.
Most of the time, a stop valve is necessary as a safety feature. These valves completely stop flow of any kind through the system, often to avert a crisis before it can get out of hand. As a result, these valves are generally close to important machinery or a human workstation. A stop valve may have a manual crank or may be incorporated into an automated system. Manual stop valves typically have a brightly coloured screw handle, the kind common in many pipe systems.
From the original1Gate Valve.com
.
Most of the time, a stop valve is necessary as a safety feature. These valves completely stop flow of any kind through the system, often to avert a crisis before it can get out of hand. As a result, these valves are generally close to important machinery or a human workstation. A stop valve may have a manual crank or may be incorporated into an automated system. Manual stop valves typically have a brightly coloured screw handle, the kind common in many pipe systems.
From the original1Gate Valve.com
.
Flexible Seal Gate Valve (205)
The co has its ex-cellent mechanical processing equipment and modernized inspecion devices, the quality of its products are stable and credible to pass the ISO9001 international quality certificate, and obtained the qualified certificae awarde by National Mechanical Depart-mentlts also promising to API Approved Enterprises and CE Obtained Enterprises. Not only entitled the Excellent Products with New Science & Technology in Zhejiang Province are the ANSI type cutting sleeve rotating plug valves, but achie-ved the National Patent with patent no: 99227876.7, with many years quality certificate inspected by the county, provincial and national inspection departments.
Since establishment, the company has always innovated and created new products by science and technology to develop the quality products conforming to the standards of ISO, API&ANSI of America, BS of Britain, DIN of Germany, NF of French, JIS & JPI of Japan, GB&JB of China, Its main products are high temperature and high pressure gate Valve, globe valve, check valve, ball valve, plug valve, bellow globe valve, and plunger valve with inside nominas diameter of 1/2"-42"(DN15-DN1050), pressure lever of 150 LB-2500LB(1.0MPa-42.0MPa), and operating temperting temperature of -101~+680, The main materials of valve are A105. WCB304, 304, 304L, 316, 316L, 1Cr18Ni9Ti, 1Cr18-Ni12MO2Ti, etc. And can smelt and produce accrding to the clients special repuire-ments, The products are hot sold in all over the coutry and to over more than 10 coun Tries and areas, i. E. Mid-east, Southeast Asia, Europe and Unite States, widely used in the fieids of chemical industrial, fertilizer, metallurgy, pharmacy, electric power, as well as liquefied petroleum gas, etc, for complement valve of introducing equipment. The company will be in the consistent pursuit of the idea of "Quality Superior & Clients First"to Best service customers from anyplace with high quality and satisfying after-sale service.
From the original1Gate Valve.com
.
Since establishment, the company has always innovated and created new products by science and technology to develop the quality products conforming to the standards of ISO, API&ANSI of America, BS of Britain, DIN of Germany, NF of French, JIS & JPI of Japan, GB&JB of China, Its main products are high temperature and high pressure gate Valve, globe valve, check valve, ball valve, plug valve, bellow globe valve, and plunger valve with inside nominas diameter of 1/2"-42"(DN15-DN1050), pressure lever of 150 LB-2500LB(1.0MPa-42.0MPa), and operating temperting temperature of -101~+680, The main materials of valve are A105. WCB304, 304, 304L, 316, 316L, 1Cr18Ni9Ti, 1Cr18-Ni12MO2Ti, etc. And can smelt and produce accrding to the clients special repuire-ments, The products are hot sold in all over the coutry and to over more than 10 coun Tries and areas, i. E. Mid-east, Southeast Asia, Europe and Unite States, widely used in the fieids of chemical industrial, fertilizer, metallurgy, pharmacy, electric power, as well as liquefied petroleum gas, etc, for complement valve of introducing equipment. The company will be in the consistent pursuit of the idea of "Quality Superior & Clients First"to Best service customers from anyplace with high quality and satisfying after-sale service.
From the original1Gate Valve.com
.
35QSQB #2 Graywater valve
y #2 graywater valve is stuck open and I cannot currently take it in to a shop to be repaired as we are on the road. I don't want to remove the entire underbelly to find the valve, so I was hoping someone could help me out and give a general area to loosen up so I can fix the gate valve.
I have not tried back flushing yet, but I did inspect the back of the cable behind the dump control panel and it looks good there, unfortunately, from there the cable goes down through a cutout into the underbelly and I can't see where it reaches. The only thing I have been dissatisfied with was the owners manual and the lack of technical drawings. I am a Chief Engineer offshore and I would say roughly 95-99% of all items (motors, pumps, etc.) come with drawings and exploded view diagrams and if they don't, the company will usually email them to me quickly. The owners manual seems to be a generic book for all Heartland trailers and is relatively unhelpful when it comes to the specifics of my unit and Heartland is unwilling to share those diagrams. I understand saying that it could void my warranty, but when your on a trip, you don't always have the luxury of dropping your trailer off for three days for a 1-2 hr (max) fix. At least for the next 5 weeks it's our home. This is not written to bash Heartland in anyway, just a personal frustration.
From the original1Gate Valve.com
.
I have not tried back flushing yet, but I did inspect the back of the cable behind the dump control panel and it looks good there, unfortunately, from there the cable goes down through a cutout into the underbelly and I can't see where it reaches. The only thing I have been dissatisfied with was the owners manual and the lack of technical drawings. I am a Chief Engineer offshore and I would say roughly 95-99% of all items (motors, pumps, etc.) come with drawings and exploded view diagrams and if they don't, the company will usually email them to me quickly. The owners manual seems to be a generic book for all Heartland trailers and is relatively unhelpful when it comes to the specifics of my unit and Heartland is unwilling to share those diagrams. I understand saying that it could void my warranty, but when your on a trip, you don't always have the luxury of dropping your trailer off for three days for a 1-2 hr (max) fix. At least for the next 5 weeks it's our home. This is not written to bash Heartland in anyway, just a personal frustration.
From the original1Gate Valve.com
.
Knife-type valve and the use of technical features of Notes
Knife-type gate valve product use and characteristics of note: the knife-type gate valve is the gate thing, flashboard fluid movement direction and vertical direction, knife-type gate valve can only be full and all related and can not to make adjustments and cut expenditure. There are two gate sealing surface, the most commonly used mode of gate valve sealing surface to form two wedge-shaped, wedge-shaped valve angle parameters vary, usually 50, wedge-type knife gate valve can be made of a whole called rigid ram; can also be made to produce micro-deformation of the gate, so as to improve its process, and cover the sealing surface in the processing point of view of the deviation process, the gate is called a flexible-type knife gate valve closed , can only rely on the sealing surface to seal the pressure medium, which will rely on the medium pressure ram pressure of the sealing surface to the other side of the valve seat to ensure the sealing surface of the seal, which is self-sealing. The majority of knife-type gate valve seal is mandatory, that is, the valve closed, will be forced to rely on external pressure to the valve seat gate to ensure the tightness of the sealing surface.
From the original1Gate Valve.com
.
From the original1Gate Valve.com
.
Pressure Gauge Isolation Valve
In my experience working in many chemical plants, there are times when restricting the opening (needle valve) to a PG is useful to dampen and perhaps prevent a cycling reading due to pulsations, so a steady pressure can be read. Gate valves are often used as they are "multi-turn" and can not be bumped open by accident causing a hazard. Gates valve more often have all metal components so are less likely to leak or pass due to chemical attack of soft materials (non metals).
Common choice is a "gauge keeper" or valve block. This is often used between the main pipe isolation valve and the PG or other instrument. The Gauge keeper typically looks like a block of stainless with some T handles. It has built in single or doudle isolation valves (including needle) and a vent. It makes the job of changing a PG quick, safe, and easy.
Sometimes to dampen or other wise protect a PG, a diaphragm seal immediately upstream of the PG is also used.
From the original1Gate Valve.com
.
Common choice is a "gauge keeper" or valve block. This is often used between the main pipe isolation valve and the PG or other instrument. The Gauge keeper typically looks like a block of stainless with some T handles. It has built in single or doudle isolation valves (including needle) and a vent. It makes the job of changing a PG quick, safe, and easy.
Sometimes to dampen or other wise protect a PG, a diaphragm seal immediately upstream of the PG is also used.
From the original1Gate Valve.com
.
2010年12月1日星期三
Gate Valve Modification
I gonna to do some modification on gate valves and I'd like to have information about a suitable handbook for the calculation of the minimum wall thickness required and other specification necessary for the final design approval.
What is the standard on which your valve is designed? The information you have provided is insuffiecient for a practical suggestion.
My Valves should be designed on API6/API2 standard. They was designed to work in high H2S concentration and at 10k psi. I can not add more details cause I inherited them whitout the right documentation.
From the original1Gate valve
.
What is the standard on which your valve is designed? The information you have provided is insuffiecient for a practical suggestion.
My Valves should be designed on API6/API2 standard. They was designed to work in high H2S concentration and at 10k psi. I can not add more details cause I inherited them whitout the right documentation.
From the original1Gate valve
.
Vacuum gate valves
Vacuum gate valves have a huge variety of uses in modern appliances. Indeed, vacuum in general is a force that is used for a number of reasons. Beyond the obvious vacuum cleaner, vacuum is also used as a power source for a number of powerful appliances, such as car engines. Gasoline engines naturally create a source of vacuum, and this is what allows the entire brake system to work, as it amplifies the pressure that is placed on the brake pedal. Without the vacuum source, it would take a very long time to stop a car going at any high speed.
However, vacuum moves things indiscriminately, and in any appliance that’s designed to use it, there must be some way to filter out the general dirt and grime that naturally gets sucked in along with the air. Also, sometimes the pressure that vacuum creates is the purpose of the device, and not whatever the vacuum could be sucking. To go back to the car engine example, you don’t want the vacuum to be sucking any debris into the engine itself, and so you need the vacuum hose to be filtered so that the debris cannot harm the source of the vacuum.
From the original1Gate valve
.
However, vacuum moves things indiscriminately, and in any appliance that’s designed to use it, there must be some way to filter out the general dirt and grime that naturally gets sucked in along with the air. Also, sometimes the pressure that vacuum creates is the purpose of the device, and not whatever the vacuum could be sucking. To go back to the car engine example, you don’t want the vacuum to be sucking any debris into the engine itself, and so you need the vacuum hose to be filtered so that the debris cannot harm the source of the vacuum.
From the original1Gate valve
.
Forged steel gate valve
These series forged steel gate valve are used to cut or connect the pipe media under nominal pressure between PN 16～PN 420(class 150～class 2500), working temperatures≤600℃.in oil industry. Chemical industry, fossil fired power plants
Forged steel gate valve
Forged steel gate valve / Technical parameters
Design reference API ASME
Design standard API6D ASME B16.34
Flanged ends Thread ends Socket welded ends
ASME B16.10 ASME B16.11 ASME B1.20.1
Flanged ends ASME B16.5
Test &inspection API598
From the original1Gate valve
.
Forged steel gate valve
Forged steel gate valve / Technical parameters
Design reference API ASME
Design standard API6D ASME B16.34
Flanged ends Thread ends Socket welded ends
ASME B16.10 ASME B16.11 ASME B1.20.1
Flanged ends ASME B16.5
Test &inspection API598
From the original1Gate valve
.
Alternatives to Gate Valves in Stormwater and Wastewater Drainage
Stormwater and wastewater (sewage) systems can be built as separate or combined facilities. The more modern houses and businesses now have separate piping systems for sewage and stormwater, while some cities are upgrading their present combined systems due to the occurrences of spillage of sewage into the environment following a rainstorm. This gate valve spillage can be from overflow at the wastewater plant or from regulators in the piping system, but both measures involve dumping raw sewage into the local environment.
This happens because of a combined plant’s inability to process the additional stormwater and sewage at the same time, preventing a back-flow of sewage to the local houses.
This is an article on flow control of drainage from wastewater and stormwater systems, in particular from combined sewage systems. We begin with a look at the some of the problems with a combined sewage plant and then move on to the control of outflow.
From the original1Gate valve
.
This happens because of a combined plant’s inability to process the additional stormwater and sewage at the same time, preventing a back-flow of sewage to the local houses.
This is an article on flow control of drainage from wastewater and stormwater systems, in particular from combined sewage systems. We begin with a look at the some of the problems with a combined sewage plant and then move on to the control of outflow.
From the original1Gate valve
.
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