Rising and non-rising stem gate valves

I was hoping someone will share a fantastic glossy catalog....nevertheless deepak, the gate valve's basic function is ...a gate moving up and down. So the stem has to rise up and down. So no question of non rising stem gate valve. Only difference it makes in the handwheel being fixed to the stem or not. If fixed the handwheel will rise else the stem alone will rise. Same is for globe valve as the port is not in line of the flow axis of pipe to help throttling. The principle is same up and down movement. non rising stems are the butterfly, plug, ball valves.

Check this glossy site of flowserve. http://www.flowserve.com/fls/Products/Valves

Regards,
Kannan.

"Paranjape, Deepak V" <deepak.paranjape@shawgrp.com> Sent by: piping_valves@yahoogroups.com 17/10/2008 07:26 Please respond to piping_valves@yahoogroups.com

To <piping_valves@yahoogroups.com>, <materials-welding@googlegroups.com> cc Subject [piping_valves] rising and non-rising stem gate valves

Dear all,

I am looking for a cross-sectional view for a rising stem and non-rising stem gate valve which shows exactly the working of both these types of valves.

Regards

Deepak Paranjape

.

__,_._,___

ANSI v/s PN Rating flange - Comparision table

To be precise, we cannot really equate the two different standards, even above 150# of ANSI. The best reliable action will be to look into EN 1092 part 1 to 4 , and look at the pressure / temp limitation table. Take note of the name diff. Working pressure vs. Allowable pressure. And the special note on agreement between manuf. and purchaser.

The above is due to the reason that to my awareness, I have not found any official standard stating the equivalent of each other. All equivalent tables are provided by only manufacturers who may or may not guarantee what they write in thier catalog explicitly. Just to have a general idea such tables can help but not for practical technical solutions.

It would be interesting to just have a look at the dimension variation of a choosen flange between EN and BS and ASME.

I like to make a reference here of a case I came across. A butterfly valve manufacturer who supplied sizes of 36", 48", 56", 64" ANSI double flanged ends. I found the flanged end OD and thickness was reduced by 40mm on an average, just around 6 to 7 mm near the bolt hole....!   When asked he says the flange will not fail even at full rating condition. By which he simply violates the ANSI and says still he can satisfy the PT limits of ANSI and it is his standard practise to follow the reduced dimension. The valves are ready for dispatch and now considering the big cost involved in cancelling the order and time delay, it had to be approved with the gaurantee letter.  In practice it does not have any problems because the operating conditions are below the rating limits, but not a safe design. Moreover it is a big cost saving for the manufacturers considering such big material, weight, machining cost reduction. The vendor is Tyco.

So take caution while considering such equivalent ones and even the ones where even the ANSI is violated as we tend to overlook the standard dimensions on the drawings.

Regards,
Kannan
Germany.

"Agrawal Sunil \(Mumbai -Stequ\)" <s.agrawal@ticb.com> Sent by: piping_valves@yahoogroups.com 15/10/2008 06:33 Please respond to piping_valves@yahoogroups.com

To <materials-welding@googlegroups.com> cc <piping_valves@yahoogroups.com> Subject [piping_valves] RE: 934] RE: 932] ANSI v/s PN Rating flange  - Comparision table

Can any one guide me what is the ANSI equivalent rating for PN below 20 (PN 2.5, PN 6, PN 10, PN 16)?

Thank you…

 

Best regards,

 

Sunil S. Agrawal

Static Equipment Dept. (STEQU)

Engineering & Design Tecnimont ICB

101/102, Interface-11, Link Road, Malad (w), Mumbai - 400 064 ( +91.22.6777.7237 * s.agrawal@ticb.com

---

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Agrawal Sunil (Mumbai -Stequ)
Sent: Thursday, July 17, 2008 11:33 AM
To: materials-welding@googlegroups.com
Subject: [MW:934] RE: 932] ANSI v/s PN Rating flange - Comparision table

 

Please find below the comparision:

 

PN         ANSI rating

20                             150 #

50                             300 #

68                             400 #

100                          600 #

150                          900 #

250                          1500 #

420             2500 #              

 

Source: Handbook of TC

 

I am not sure about reliability of above data and hence I request other member to contribute.

 

 

Best regards,

 

Sunil S. Agrawal

Static Equipment Dept. (STEQU)

Engineering & Design Tecnimont ICB

101/102, Interface-11, Link Road, Malad (w), Mumbai - 400 064 ( +91.22.6777.7237 * s.agrawal@ticb.com

---

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Darji Nilesh (Mumbai - Machinery)
Sent: Thursday, July 17, 2008 10:19 AM
To: materials-welding@googlegroups.com
Subject: [MW:932] ANSI v/s PN Rating flange - Comparision table

 

Can any one provide me a subject table.

 

Nilesh.

PSV interlocking

Sorry I came after a long weekend.

In the HP steam service, in situations where to be in line with API area limitation, it is necessary to distribute the capacity with multiple valves to achieve the relieving capacity needed. Where such 20 PSV collectively are used to discharge in which one is left as spare.  So to ensure all 19 valves are open, the interlocking is applied and simple carseal open is not used. Actually for plant operators CSO is easier. But when situation arises where it is only channelized to a diff. PSV and not really meant for maintenance, CSO does not perfectly suit.  Yes we can reduce the number of PSV considering the specialized ASME sectionwise highcapacity PSVs, but it is left to the discretion of the safety engineer. But the pressure in the need of the valve dimensions for the piping layout group is forcing the safety to adopt this API config. solution where the dim. is already available in the standardized form and can still proceed in layout engg while awaiting for the order being placed.

As only one is accounted as a spare out of the 20, all of equal capacity lined up parallelly, I am afraid if any backpressure would develop, as the margin of all put together is equal to one PSV capacity minimum, even if one fails the remaining 18 would still take care of. This multiple distribution is better off than fewer in such failure cases and to ensure least chattering happening.

Regards,
Kannan
Germany.


On Oct 8, 2008, at 4:41 AM, kannan.sundaram@linde-le.com wrote:

> Additionally, where in some cases where a network of 20+ PSVs are
> interlocked the CSO does not serve the purpose.
Just for my own curiosity, how do guarantee that a PSV can operate
independently if it's interlocked with 19 others. I was always taught
to avoid like the plague the possibility that the operation of one
valve might interfere with the operation of another. What sort of
situation requires 20 interlocked safety valves? How do you avoid a
circumstance where one of the valves might put a back pressure on one
or moe of the others?

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/

Strip check test and wedge material

Two possibilities

1) Copper strip test for LPG gases. check the link.

http://symp15.nist.gov/pdf/p153.pdf
http://www.onyxnet.co.uk/clients/mastrad/copper.htm

The COS impurity can form H2S which comes under NACE. So is why the copper strip test is done. In your case it has no meaning as it is relevant in the msd activity of basic engg.

Other metal strip tests are existing like the silver etc.

2) It is corrosion test.(By coupons as in NACE)

http://www.freepatentsonline.com/4338097.html

Also check perry's handbook 28-10 on testing methods.

This test gives the measurement of rate of corrosion simulating the actual process condition. Like the background of nelson curves. This is not the job of the EPC contractor but the job of the Basic engg company and licensor to define what choice of material to withstand the life of the plant and define the required corrosion allowance. Detail engg. is NOT basic engg. In detail engg. we can just ask the vendor to comply with NACE std. for the ITB material prescription. Such corrosion test is very expensive and time consuming as it takes weeks to corrode the metal and measure the reduction of thickness. Calling the vendor to do such test is nonsense. If he can stamp NACE compliance, it is understood he has done such a sample test to get the accreditation for a few years period.

The third possibility I am waiting for the vendor's reply latest by tomorrow and it seems it was done few years ago for a project by one of his colleague.
 
On acceptance of forged and casting, in general till 4" the forging is offered by default. It is better not to define it in your datasheet. If required you can use the same breakup of the body(forged/cast). If you have not defined and vendor offers all in casting reject and ask him to follow the body size break as a min. However there are some good cast materials used for stem against barstock. Such castings can be accepted depending on the process area and your overall understanding and judgement of the frequency of operation and the operating pressures.

The above is applicable for all kinds of obstructer.

With regards,
Kannan

********************

One more query..
Whether to accept cast material for disc/plug/wedge instead of forged.I m really confused ,becaus all our vendors have offered cast material.


-Strip check test is required for 1% of total ordered quantity of valves (min. 1 no) for all valves in process / NACE / Hydrogen application
 
This is our ITB requirement.& vendor has regretted to give the same.
I have searched on net....but didnt get exact test procedure, related to valves.

Regards,
Sheetal Patil

Aker Solutions

Piping supports.

This piping support manufacturer has a big spectrum of products and does custom designed supports catering to the special needs.

To members who are not aware of this supplier check this site for more information.

www.lisega.de

With regards,
Kannan Sundaram.

Three Way Valve Interlocking.

In addition to our earlier discussion on the subject, I verified with operations people and that an additional reasoning based on their practice in dual safety valve, is that the situation is, the PSV is gone for maintenance or inline/cutoff from the system. And the same status is to be known at the key cabinet. So if the PSV-2 outlet LO key is in cabinet it is understood that the PSV is in maintenance. if it is in the inlet valve of the PSV-2 along with the second key which is used to unlock and close, it is to be understood as that it is only a cutoff.  Also during maintenance the pipe spool is placed to replace the PSV and incase of any leak in the closed inlet valve, the pressure build-up is avoided by keeping the outlet LO.

As per the operation person it is important to know the PSV status in cabinet to verify the maintenance records.

So LO of outlets has to be interlocked with inlet and not independently LO as a GEP.

In addition I understand Netherlocks has recently comeup with new locking devices in which some valves which are not reachable as in your case, can be controlled by the flexible metal  wire covered in plastic sheath like an electrical cable and can be located anywhere and can operate a raising stem valve. And the key can be removed or inserted using the extension rods. It looks quit neat and without any disturbance to any piping.

Smithflow guys say as per thier experience they do not have a better solution than the same wire cable for such changeover valves.

One more news is that all big oil and gas vendors are presenting themselves in Dubai trade fair. So any one in the region could benefit.

With regards,
Kannan.

RE: [piping_valves] Three Way Valve Interlocking.

Netherlock always expects and replies only for big orders. If the order is more than Euro 1million, the founder of the company will reply you back. It is not a good approach though.

Anyway. coming to your email, the observation of your PID snap shows a FG/FS, possibly fuel gas with insulation/heat traced. But the No pocket note is strange there being a gas. So definetly we cannot bring the arrangement at floor level of the vessel. So operating the valve at such height without a platform, going to be a special task. However as the top nozzle of the vessel has a fig.8. and a manhole and I expect some arrangement to reach the top. And the change over valve being a raising stem, and the simultaneous operation is required of both the valves, chain-wheel is the best cheap solution. Have a look at the below snap of Netherlock where the long rod also is available to handle the key.

With regards,
Kannan

"Bagesh Kumar" <bagesh.kmr@gmail.com> Sent by: piping_valves@yahoogroups.com 12/09/2008 13:51 Please respond to piping_valves@yahoogroups.com

To <piping_valves@yahoogroups.com> cc Subject RE: [piping_valves] Three Way Valve Interlocking.

If you can throw some light for the interlocking between these Two Change over Valves , Although a vendor has suggested a chain interlocking, which is not looking suitable at this kind of application, I have tried to contact the Netherlock but didn’t recd any reply.

Thank u once again for your suggestion.

Kumar Bagesh

Three Way Valve Interlocking.

Sorry I overlooked the three way valve you had mentioned.

Here I would like to draw a similarity, though the valve constr. and design are different, in ethylene cracking a changeover valve is used to switch from cracking to decoking mode. I happed to observe that flow pressure condition during the change over is significantly affected by the changeover valve and the downstream valves were required to achieve the right condition. Similarly, if you observe the various scenarios of the inlet flow condition under which a safety valve is designed for, the functioning will be affected, like chattering and the availability of the 3% margin.

But even with the two way valves at a transition point both the valves are 100% open and both the PSVs are available and will start chattering, but you have the advantage that the 100% relieving is available at any point of time. But in a changeover valve the 100% relieving is not there as at 50 % open condition the flow is split at 50%, compounded with a situation where one safety valve is malfunctioning, you are at more risk. But you have a bargain that the transition is shorter and easier operation than a two way valve. But if the upstream vessel is of large volume and you expect the PSV size to be in the range of 1" to 3", the 3way could be used.

But again, the outlet and inlet has to be interlocked even in case of the 3way valve, if the PSV-1 inlet side is open, PSV-2 inlet side closed and the outlet side of PSV-1 is closed and PSV-2 outlet side is open, which is possible without an interlock.

Most of the vendors who manufacture such changeover three way valves do guarantee the flow area remaining constant during the transition but in case one PSV has failed the vessel is in high risk for the short duration of the 3way valve operation.

With regards,
Kannan

"Bagesh Kumar" <bagesh.kmr@gmail.com> Sent by: piping_valves@yahoogroups.com 12/09/2008 10:45 Please respond to piping_valves@yahoogroups.com

To <piping_valves@yahoogroups.com> cc Subject RE: [piping_valves] Three Way Valve Interlocking.

But the Valve is not simple Three way, It’s a change over Valve, I agree with your answer for interlock, but the change over valve working principle explains clearly that It is not possible to block the flow, i.e if one closes other side opens simultaneously and in any case the inlet side is always open.

Kumar Bagesh_._,___

Three Way Valve Interlocking.

The answer is simple.

Imagine if someone mistakenly closes the PSV outlet block valve, what would be the scenario. To avoid that, the interlock should be there between the inlet side and the outlet side of the dual PSVs.

The sequence goes like this....the outlet valve of PSV-1 which is in locked open using first key and the key is removable only if the valve is in open position and for closing that valve the first key is required and the inlet valve of PSV-1 which is LC to be unlocked and with that first key and is opened and LO using second key  and this key will be removed after locking and will be used to unlock the inlet valve of PSV-2 and the valve is closed and locked using third key and this key is removed and inserted to lock open the outlet valve of PSV-2 and this means the third key stays there in LO and that the outlet valve cannot be closed.

The core purpose is that both the outlet valves are open irrespective of the respective inlet open/close positions and that it can never be closed and to enable one stream to be opened before closing the other stream. So interlocking will be required either in three valve system or two way valve system.

Even your first initial PID is also incorrect. It should have the PSV outlet side valves also interlocked.

Additionally, my recommendation is that never use a three way valve for a safety valve as the reason for two valves and two streams is for safety reasons that even if one stream is having a problem the other one is available. It is not a matter of cost saving but  a safety matter.

With regards,
Kannan

"Bagesh Kumar" <bagesh.kmr@gmail.com> Sent by: piping_valves@yahoogroups.com 12/09/2008 03:18 Please respond to piping_valves@yahoogroups.com

To <piping_valves@yahoogroups.com> cc Subject [piping_valves] Three Way Valve Interlocking.

Dear All,

                Please suggest me why interlocking is necessary in Dual relieve Safety Valve, My issue is like this,

In a Russian project the Licensor PID specified the single relief valve diagram. After detailing our process team found that Dual relief Valves are required, As the detailing went on they generated the scheme for Dual relief Valves with Two Gate Valve in inlet and Two in Outlet by single operation scheme, i.e. One Lock Open and one Lock Closed, Process team wanted to purchase an interlock system between both Gate Valves, Then it came for material parts, I suggested them to use two Three way Valves in dual relief operation, because I had used it earlier in a plant of Zimmer licensed, and the operation of these valves are similar to my project requirement, after that our PID with both diagrams went for an approval to PMC, now PMC wanted to use this Change-over Valve system, but interlocking to be done between Inlet three way Valve and Outlet three way Valve, I remember previously I have not used any interlocking between these.

My question remains,

Why Interlocking is necessary between these two changeover valves in Dual relief Safety Valve operation, Although Vendor is ready to provide interlocks between these.

I request member suggestion.

 

Attached is the scheme suggested by me, after that PMC added interlocking provision.

 

 

 

Earlier it was like this.

 

 

Regards

Kumar Bagesh

Use of DIN material in B31.8 design practice.

ST52.0 which is equivalent to 1.0421 / A519 and ST52-3N which is equivalent to 1.0570/1.0576 / A516, A572 can be used for the purpose inline with B31.8 para 811.221 being an official equivalent of ASTM material.

With regards,
Kannan

"Mohammad Yaghoubi" <yaghoubi_m@nigc.ir> Sent by: materials-welding@googlegroups.com 11/09/2008 12:07 Please respond to materials-welding@googlegroups.com

To materials-welding@googlegroups.com cc Subject [MW:1097] MATERIAL APPLICATION

DEAR SIR
CAN WE USE PLATES OF DIN1629 ST 52.0 OR DIN17121 ST52.3N TO MANUFACTURE
SPLIT TEE ACCORDING TO ASME B31.8
BEST REGARDS
MOHAMMAD YAGHOUBI

----------------------------------------------
National Iranian Gas Company
http://www.nigc.ir