Branch components.

Firstly, I would like to highlight the word latrolet, weldolet are proprietary names of BF. However it has become synonym in the industry to use those names which is not correct. It is also referred as branch-olets prefixed by 45 deg, 90 deg, etc. not to confuse with proprietary name. Even the ANSI codes do not refer BF names.

Coming to the question, no doubt it is a seamless pipe made reinforced branch fittings. The beveling also looks fine for the profile of the pipe. Being a non standard size, the dimensions have to be verified  with the manufacturer only. But if you ask if forging or pipe made item is acceptable, the answer would be...both can be accepted as the subject is the reinforcing area and cross section thickness.

Additionally, the general opinion is that the BW Reinf.branch fittings has to be used within the available STD, XS, XXS, 160 is not correct. Though being standardized by manufacturer's, we can prescribe actual thickness requirement within B36.10/19 and to std plate thickness. As per my verification all the manufacturer's facility has the flexibility to manufacture the same.
For eg. MEGA a reputed manufacturer in Bergamo, near Milano, Italy is on such vendor. I would say apart from BF, they are the best company with the know-how of  reinforced branch fittings and any other forged components. Their catalog gives a detailed dimension of all types of Rienf. branch fittings for all thickness and diameters of B16.10/19, including the 32".

http://www.mega-spa.com/index.php?option=com_content&task=view&id=28&Itemid=43

Moreover some forging manufacturers like MAWO fittings in Germany do make special designed branch components which are not really looking like a 'olet nor a coupling and not always forged. Such components have been tested and proved at site and has less material and flexibility in mass manufacturing and of course cheaper than the so called weldolets or sockolets or flangolets etc. And the good part is the B31.3 code do not pose any restriction in such configurations. Pl. take note these components are proprietary of their customers such as BASF, Linde for example.

So I would suggest to use the freedom of the code to invent and design your own new, cheap and economical and ease in welding with reduced fabrication and testing costs by avoiding the cumbersome welding process involved in the BW branch fitting. The best would be as Raghu suggested, the RF pads, but that also has its disadvantages in the operation life span.

Regards,
Kannan.

On Fri, Dec 12, 2008 at 11:19 AM, Bathula Raghuram (Mumbai - PIPING) <R.Bathula@ticb.com> wrote:
Can any one pl. share their experience on large size latrolets? I have not seen latrolet like this shape before, it looks like the vendor has taken a higher thickness pipe and machined to suite the curvature on run pipe. It s 32" x 28" latrolet weighing almost 670 Kg. in absence of catalogue for this size or any dimensional standard really it's impractical to judge whether it is a correct type fitting or not?

KAMOS RTJ Gaskets

I have not used this gasket but heard of this from one of the vendors. To what I understand from him and later discussing after your email, it seems it does reduce the time as you mentioned due to the difference in the method of testing. And as per the vendor this gasket does not have any disadvantage compared with the conventional ones from the operation experience point of view. But the concept is not new as other companies like kroll and Zieller are attempting on such variations.

Another special design gasket is available and being used by some companies like BASF and Statoil. The company is Jungtec, probably a more unfaimliar company. But they have good ideas and working design concepts and good long experience in field, on gaskets. On the subject of leakage after maintenance Jungtec is quit good.
Thier site is http://www.jungtec.de/en/productsoverview.html

For our friends to know more about the subject gasket... http://www.karmsund.no/2.1_kamos_rtj.htm

With regards,
Kannan.

Mohamed Ibrahim <mibrahim_ak@yahoo.com> Sent by: piping_valves@yahoogroups.com 20/11/2008 15:13 Please respond to piping_valves@yahoogroups.com

To piping_valves@yahoogroups.com cc kannan.sundaram@linde-le.com Subject [piping_valves] KAMOS RTJ Gaskets

Dear Friends,

 
Can you anyone please advise as you have ever used KAMOS RTJ Gaskets in your project as our client TOTAL asked us to see the feasibility to use such Gaskets in our Pipeline Project. Normally these gaskets will allow us to skip the standard leak test,cost reduction and can reduce down-time connected with testing.
 
Best Regards,
 
Ibrahim.

Design standard for ball valve

Dear Nitin,

Unofurtunately I was on leave and took sometime clearing all my personal emails. However it is disappointing our dear members have become more reluctant and lethargic to have discussions mutually benificial.

Coming to the query, to my knowledge of American standards, this size and rating is not covered for the obvious reason being unusual and are yet to be standardised. The solution in your case is to indicate the design to be in acc. with API 6D and F/F to manuf. std. I also have doubt if any manuf. will make a RB valve in that size. So you may have to consider only FB type. For testing of such valves ensure you mix API598 and API 6D to suit the design and service condition as many suppliers practically are unable to meet API 6D creteria for such large size. This is from my inspection experience.

If alternate valve type can be thought about in your application, definitely you should take that change. The key reasons being the maintenance of seats, back flushing, stem packing overhauling is going to be more complicated than any other on/off valve or even a flow control valve. Last but not the least, cost varies in the region of 25 to 40% more. for valves above 32".

So use of ball valves above 28" should have the right reasons.

Regards,
Kannan.

"Hanamapure Nitin \(Mumbai - Piping\)" <N.Hanamapure@ticb.com> Sent by: piping_valves@yahoogroups.com 07/11/2008 06:55

To <piping_valves@yahoogroups.com> cc Subject [piping_valves] Design standard for ball valve

Dear all,

I am looking for design standard for 600#, 42” LTCS reduced bore ball valve used in sour service.

Could anyone suggest me the design standard?

Thank you.

Best regards,

Nitin Hanamapure_._,___

AISI 307 reference.

Dear friends,

Atlast after pushing the sales manager and contacting the design manager directly, I found that the AISI 307 was wrongly indicated in their drawings and that it is a welding wire used for dissimilar welding to be designated as 'AVESTA 307-si'. It is being adapted by these manufacturers for cutting cost on the price of such valves in overall, by a welding overlay on the valve body itself. And having good hardness of 220 BHN and with the usual trim of 13Cr/316/304 the seating/disc hardness difference is taken care of. Incase of maintenance the welding is lapped onsite. No seat rings, threading, seal welding of the rings needed...looks a good idea and it does depend on the type and constructional design aspect of the valve and the fluid system.

The link provide by the Design manager of one of the valve company.

http://www.avestawelding.com/2813.epibrw

Also I found that the AWS designates as 'A 5.2 E 307' of the solid wire type with slight difference in the composition as per AJ Marshall's manganese steel welding info. And another one called 'super 307 / AWS E307-16' from SuperTech, Germany. Looks a lot of variations are available under 307.

The subject valves involved in my case was conventional check valves & NS check valves.

With regards,
Kannan Sundaram.

   
Dear members,

I would like to know more about AISI 307 which is being used by certain
suppliers as a seating of valves. The suppliers are not able to give the
exact ASTM references, but they say it is ...more or less....equivalent to
X15CrNiMn188(1.4370) of DIN. However I found this DIN material being used
generally to make check valve pins. I am having doubt if it is a
precipitation hardened steel category(which is usually prescribed for
stem/disc/ball/blade/diffuser materials requiring high strength) or a
something related to welding rods.

From my search it looks more of a welding overlay material. However I
could not find any ASTM specification reference of it. Can somebody
specify the same for me to check out the details.

With regards,
Kannan Sundaram.

Valve Datasheet templates

Dear members, sorry to forward this email quit late as I was on vacation.

 

This link looks quit informative.

----- Forwarded Message ----
From: Goran <goran_maaspers@hotmail.com>
To: kannan_cit@yahoo.com; ahmedeissa16@yahoo.com
Sent: Friday, November 21, 2008 6:43:42 PM
Subject: Valve Datasheet templates

Hi guys,

 

I stumbled across your correspondence at piping-valves.blogspot.com regarding Valve Datasheet templates.

 

This link may come handy: http://www.standard.no/acrobat/L-001/VDS/index.htm. These data sheets are used as is or customized to specific requirement by the norwegians. Use with sound engineering practice.

 

 

Best regards,

Goran Maspers

Sweden

Hydro test-max holding period

The holding period depends on the time needed for inspecting the system thoroughly. Minimum is 10 minutes. Especially the gas tests calls for 100% weld and mechanical joints being examined.
Also we have to ensure the limits of test pressure defined by individual components also to be taken care not to damage the components for eg. the soft seating or lining or to replace them with pipe spools.

To my info the repeated call for Hydrostatic test on the same system, the pressure need not be changed from the code to its design pressure as most of the case if any major leaks are identified, the test is performed again at the same pressure and not to reduced pressure. It is independent of the holding time. Holding time risk are purely defined by inspecting time and the in-line components and not of the piping components. It is a usual practice to remove all in-line components which has reduced testing pressure conditions.

The maximum test pressure is the pressure at which the pipe reaches its yield stress. In most of the cases the problems can be tracked back to the original thickness calc of the piping system where in somecases you may find the thickness not sufficient to take the test pressures but will suit the design pressure. When you design the piping class for rating condition you may have some margins to accommodate the test pressure but not always especially in the larger size range above 24". This makes the site testing team to reduce the test pressure adjusting to actual pipes purchased and being used and of the elevation impact of the system. Also piping connected with vessels pose a diff. situation and defining the test pressures requires a different judgement as the approach differs from company to company.

Most important thing is to question the need of hydrotest for a system to process dept. who defines the requirement.

Regards,
Kannan.

Aarpee <ramprasad.chari@gmail.com> Sent by: materials-welding@googlegroups.com 24/10/2008 08:29 Please respond to materials-welding@googlegroups.com

To "Materials & Welding" <materials-welding@googlegroups.com> cc Subject [MW:1236] Hydro test-max holding period

As per B31.3 Hydro test is carried out at 1.5X Design Pressure.Holding
time for Piping spools is normally 30 minutes but at times 4-6 hours
for Gas applications.Can this be held for 24 hours?What is the
potential risk?It is normally indicated that after Hydro inspection
for 10-30 minutes at 1.5X Design Pressure,if you intend doing further
inspection then same can be done at a pressure not more than the
design pressure.Opinion of the group is being sought thro this mail
Regards
Aarpee

Vacuum Insulated Piping - VIP & Thermal Compensation Guide - TC

Members involved in LNG could be interested in the TC guide / Thermal Compensation guide applied in LNG. The liquifaction units of Hydrogen, oxygen etc. supplied by Linde are using this and such ones were used in the ISRO's cryogenic engine testing bed facility where the Chandrayaan's PSLV was tested.  For literatures follow the link below

http://www.phpk.com/products-pipe-vacuumlng.htm

Moreover the Hadron corridor where the 2/3 degree kelvin super magnet accelarators used these VIP-Vacuum Insulated Piping and additional advanced hi-tech insulation for the cooling system. Though the current failure is blamed on the cooling system but being highly complex, the source of the problem is still to be identified.

Regards,
Kannan.

Netherlocks information

Dear Mr. Gielissen,

 
Thanks for your concern and reply.
 
I am happy to communicate in this public platform with you and of the reach this platform has. More happy I am, about the seriousness as an organisation Netherlocks is of the market reach and basic problems some customers had faced.
 
I am sure the group members will also be happy to know of Netherlocks position and seriousness it has with its existing and potential new customers.
 
I am also sure you know me as the same Kannan Sundaram from Munich and we had met each other sometime back.
 
I never had the doubt about the product or the improvements and innovation happening in your product range. And of the reliability of Netherlock products in the long run having seen your product at few plants, I had been. I am aware of those client's satisfaction and long term relation they have with Netherlocks. Infact the name Netherlocks has become a synonym of mechanical interlocking to many in the industry.
 
The fundamental issue of concern is the response time for certain technical clarification on your products and solutions. As you know some companies who does small process or utility units may not have significant requirements of mechanical interlocking devices and some companies who have significant requirement but are more cost concerned. These are known to the suppliers and more specifically the local trading partners and they have a practice in not responding or slow in response, similar to the situation faced by one of the member who raised the question with Netherlocks. And to me during my handling of LNG terminal, Hazira, Gujarat project.(A Shell company). And others who had other different experiences.
 
Unfortunately some engg. companies do not have a comprehensive company standards and designers go by thier understanding of the product. This kind of platform helps people share thier personal experience and the understanding of the product. Personally I feel a company confident of having the best product should also help in having the product understood in the industry utilising the oppurtunity of people seeking advices or who may ask the very basic questions, irrespective of having the potential of recieving the order and the more Netherlock will dominate the market having the first opinion as the best opinion in the young minds who may lead a project someday. I do agree your website give quit exhaustive details but still open question does exist always. I have seen process engineers and safety engineers who are not aware of the sophistication and complexities possible with the mechanical interlocking, who are supposed to be the originators of such requirements.
 
In conclusion I suggest Netherlocks should lay down rules to its local partners in their way of approach to the local customer base. And you could possibly have a blog opened similar to the way the Microsoft  or HP's IPAQ choice have independant websites for each product and they clarify the simplest questions and discuss things out of the manuals and reference materials of the product itself. May be that could help Netherlocks to have a direct contact for plethora of new ideas and to have an insight of situations at site and at engineering office, especially from the process/safety engineers, helping to understand the other side of the world apart from the feedback from your service engineers at site, having said the channel of communication is also long due to the multi-tier protocol in certain companies, in overall can bridge the gap for mutual benifit and override the word of mouth views of the company.
 
Lastly, to start with, I did develop an alternative design solution avoiding the one and the only spring in your MRL series. Similar to the key hole closing pre-stressed metal plate can be used as the typical position of the valves in the plant makes it more prone to collection of sand particles in the crevice area. The location of the spring currently is in the corner, when the sand accumulates, the spring functioning is more likely to be obstructed. Using the pre-stressed plate the area is cleared off and lever piece can slide on the coated stem freely hanging on the metal plate. The sliding movement can clear off any sand. The plate can be located and oriented to ensure there is even erosion of the stem coating. Refer the attached sketch. Hope this reduces the cost and simplifying the device.
 
Your team could evaluate that and let us know of Netherlock's feedback of it.
 
Thanks again for this interaction and helping the group members to know the interest and concern of Netherlock towards its customers.
 
The above views are of my own and do not reflect the opinion of the organisation I work for or have worked for.
 
Kind Regards,
Kannan.
 

---

From: Frank Gielissen <FGielissen@netherlocks.com>
To: "kannan_cit@yahoo.com" <kannan_cit@yahoo.com>
Sent: Tuesday, October 21, 2008 12:24:36 PM
Subject: Netherlocks information

Dear Mr. Kannan,

 

I saw some correspondence on the piping and valve information Blog from last August regarding Interlocking.

 

Firstly you are quite well informed on the subject, have you worked with our company in the past?

I see you are located in Germany, are you still working there and for what company may I ask.

 

I am sorry to see your experience with Netherlocks is not that positive since you mention we only reply for big orders, I would like to emphasize we are always looking to assist companies were possible, actually we are known for our good relation with clients and custom made solutions.

 

SoI hope we can be of assistance in the future, even on small projects and if you would like to get in touch with any of our sales people for an update on our products I would be happy to introduce you.

 

I look forward to hear from you.

 

Kind regards,

Frank Gielissen

Sales Director

 

NETHERLOCKS

Valve datasheet templates

I am sure no one will be able to share such company proprietary information. However you have enormous information in the internet available for general education purpose, which you could adapt to your needs. Also a vendor catalog gives the breakup of a valve with the bill of material which you could start with.

One particular thing to be taken care of is not to be too detailed and very specific which will pose problems in getting offers from vendors and with much non conformity issues after order.

The following sites will be help to you to understand the framework of piping classes and specification content and ofcourse of the relevant valve specification. PIP.org has good resources with a cost.

http://www.pip.org/downloads/Sample-PN01CS2S01.pdf
http://www.pip.org/downloads/Sample-PNSMV003.pdf

Regards, Kannan. --- On Tue, 10/21/08, Ahmed Eissa <ahmedeissa16@yahoo.com> wrote: From: Ahmed Eissa <ahmedeissa16@yahoo.com> Subject: data sheet To: materials-welding@googlegroups.com Date: Tuesday, October 21, 2008, 4:09 AM dear,eng   can any one send me specification data sheet for valves (globe,gate,check,ball),or any sample format, i have to prepare it for my company, and i do not have good experience about this matter, so please any help wil be apreciated . thanks

Rising and non-rising stem gate valves

Thanks Vinayak for letting me know of this principle which I was not aware of. Always I found the vendors offering rising stem only.
Now I have to dig out what size ranges such valves are available and the reliability of that stem/internal threaded disc design.

Thanks
Kannan.


Dear Deepak ,

Plz find attached document , which shows details view of rising and non-rising stems
 
Regards,
Vinayak Nivendkar.

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

Copper gasket.

Even the nonstandard solution is being adapted and in most cases the site personnel do violate the codes and standards to find some solutions specifically without even consulting the engg. office.

So I go by what Bhattaji says as, it does pose serious hazard being a 1500# rating and with a gas service. A big potential for a high speed accident. The reasoning for this is simple. The B16.5 flanges does increase in the OD and thickness of the flange and the hub as the size increases and does have the backing for those dimensions under those Max. Working Pressures. Already it is a weak point in a piping system and if you are prescribing a flange dimensioned for 2" and going to use as a 2.5" connection, moreover a bored flange without a hub, which makes it the most weakest point. A 6mm fillet weld cannot substitute a hub.

So use of SPW / copper gasket can be at the descretion of site and if from engg. office it is to be replaced with a 2.5" reducing flange. As Bhatta refered the bore dim., which is a purchased defined parameter and the para 6.8 very well says that the hub will be as per 2" and thk/od as per 2.5". So I do not find any problem in going for it.

Sometimes such decision is like being with angel / devil.

With regard to your other query, in ethylene plant copper is used only in some cold fraction part and not as a flat gasket but as a V groove O-ring gasket. Aluminium and copper are also used in air seperation units . The torquing calc is the standard procedure and same as the ring joints. But I remember some posting was there by Raghuram some time back on the subject. Pl. check the group's archive.

You can also check http://www.futek.com/boltcalc.aspx

With regards,
Kannan



Thanks Kannan,

 
Kannan, please ignor questions in earlier mail.  
As you said the comparision of diameters was done and we were able to eleminate most of the cases which were originally thought to be problematic.  On most of the cases comparing the gaskets ID and instrument tube OD, it was found that standard 16.20 spiral wound gasket can be used.  So the problem was reduced down to small numbers.
 
As you have said that standard SPW gasket torquing cannot be used for copper gaskets.  Is there any reference to calculate the required torque?
 
regards
yogesh

Copper gasket.

Dear Kannan,

Good Morning!
I do repeat again that the problem case is a simple SPW gasket case.
I find it difficult to convince myself while wasting my effort on
somebody's fertile idea of using copper gasket.
Regarding your sportive comment, please do appreciate it is a non-code
example of using expanding flange. Such type of flange is indeed a safety
hazard for higher pressure rating.
I can do the "re-inventing of wheels", if I have time and certainly not in
this unsafe case.
Pertaining to your alternative solution "...Coming to B16.5 compliance, the
other alternative, if it is few points in the plant, replace the 2" flange
with 2.5" x 2" ...", kindly ckeck the boring size limit in the B16.5 table.
Thank you again.

Kind Regards,
Bhatta.

*********
Additionally, for our Bhattaji as quoted below,

"I think that you should also similarly respond to site, without breaking your
head."

These problems do occur due to the negligence of the white color engineers siting
in A/C office and doing poor engineering. So white colors do have to break thier
heads to find solutions to thier mistakes as we are called as engineers by our
site colleagues. So we have to engineer it.

This problem is a well known purposeful ignorance by the piping material engineer
who does not co-ordinate with the instrumentation specialist. And he ignores to
comment or talk to piping material engineer. The big excuse and a fact is that the
orders of the intruments are placed after the instrument assembly specification
prepared by the piping material engineer is closed and forgotten and IFC
isometrics is in progression.

So the site can be spared only at the will of the two colleagues involved.

Just a sportive reply dear bhatta.

Happy piping.
Kannan.

Copper gasket.

Temporarily ignoring the subject of expanding flange as being not covered under B16.5,

considering your pipe thk as sch160 for 2", doing a small check, the SPW gasket inner dia is 58.68mm for 2" and outer is 85.85mm. The pipe inner dia is 42.82mm for 2" and 53.94mm for 2.5". So using a SPW gasket without inner ring, the protrusion/obstruction of gasket is not going to be there. And the flange and blind flange are 2" and will not have problem in diff of RF facing dia. Also the step of hole dia change is 5.56mm which is not an issue for any instrument item for sure. So you can use SPW without inner ring, however for the service indicated by you it will definitely be required frequent replacement than with a inner ring.

Speaking in general of the use of copper gasket, yes what the vendor says is true in case of cyclic loading, else it can be used. I do not feel any cyclic loading is going to be there for the service mentioned by you. After every maintenance it will have to be replaced like the soft rubber or metal ring gaskets.And you can never apply the SPW torquing for it.  For your info even Aluminium gasket are used.

Now the solution as copper gasket for your situation is not suitable and you have to go soft iron. But not as a flat one but as o-ring gaskets on a V-groove flange. This could be an alternative solution for you. You could use 90 deg. V groove of 2.1 mm depth on the RF at 80mm diameter which is near to the outer dia of a SPW gasket and use a soft iron of 5mm dia. Finish/tolerance of the groove shall be similar to a ring joint flange. This innovative site solution is used in normal 125 to 250 AARH, RF, B16.5 flanges and have been a proven solution. But you have to calc. your torquing table for these joints. But the torquing data is very similar to the ring joints. In case of 2" it would coincide, but verify from your end. Moreover your services would go well with soft iron.

For the SPW gasket property info the best resource would be the inventors of SPW gaskets, the flexitallic (http://www.flexitallic.com/pro_semi_spiral.html) Also they do give reply in a day or two.

Coming to B16.5 compliance, the other alternative, if it is few points in the plant, replace the 2" flange with 2.5" x 2" reducing WN flange, and with 2.5" bored blind flange, this will ensure you are in line with B16.5.

With regards,
Kannan

yogesh modak <yogeshm28@yahoo.com> Sent by: piping_valves@yahoogroups.com 04/09/2008 09:55 Please respond to piping_valves@yahoogroups.com

To piping_valves@yahoogroups.com cc Subject Re: [piping_valves] Copper gasket.

Thanks for your mail.  

Will go through the tables and other material mentioned by you.  
However another query regarding mechanical properties of copper under compression. Can we use standard bolting torques while using copper gasket?
Any informatino on mechanical properties of Spiral wound gaskets?
 
thanks & regards
yogesh

----- Original Message ----
From: "Bhattacharyya_Bibekananda@ke0.grp.kaneka.co.jp" <Bhattacharyya_Bibekananda@ke0.grp.kaneka.co.jp>
To: piping_valves@yahoogroups.com
Sent: Thursday, September 4, 2008 2:21:10 AM
Subject: Re: [piping_valves] Copper gasket.

Hi! Yogesh,

Thanks for the input.
I understand the situation. And it is a straightforward case indeed!
Please refer ASME B16.5 Table 6 or Table 7 (I do not have it in front of me
right now.) with title as “Reducing … Flanges for Classes … “. Please read
the table and notes very carefully.
The case of modified flange (as indicated by you) is basically an
“Expanding Flange”. Code only permits reducing flanges with boring size
limits. Please read the table.
I hope that it will be clear to you.
For non-Code and poor engineering practice cases, finding a solution is
like “re-inventing wheels”.
I am sorry that I cannot help you in this case.
For additional reading, you can refer ASME B31.3 paragraph 304.4, 305 and
306, which talk about listed and unlisted components.
I think that you should also similarly respond to site, without breaking
your head.

Kind regards,
Bhatta.

yogesh modak
<yogeshm28@yahoo.
com> To
Sent by: piping_valves@ yahoogroups. com
piping_valves@ yah cc
oogroups.com
Subject
Re: [piping_valves] Copper gasket.
09/03/2008 11:38
PM


Please respond to
piping_valves@ yah
oogroups.com


Requested parameters:

1. #1500

2. design temp. 100°C

3. Fluid type - Glycol / De-Emulsifier (De-oiler) / Nitrogen Gas

Flange details

Piping side is having standard 16.5 raise face flange.

Instrument side is having Modified blind flange. 2" blind flange bored to
accomodate approx 2.5" instrument meter pipe. Due to this the raise face width at
instrument side is reduced and so standard 16.20 dimension gasket does not fit.
The flange type based on the drawing of vedor is similar to fig. 4a

ASME SECTION VIII DIV 1 appendix 2.

I have done the stress calculations as per ASME but that does not answer the point
raised by vendor i.e copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.

Also the required torque calculated using the Min design seating stress required
for flat copper metal gasket (Table 2-5.1 of ASME) is very low as compared to the
standard torque values used for bolting. And if that values are used than the
initial stress on copper gasket goes beyond UTS. Since gasket will always in
compression comparing with UTS may not be correct. Is there any value fo copper
gaskets upto which the copper gaskets can be initially compressed?

Also would like to know if available, mechanical properties of sprial wound
gakset.

Regards
Yogesh

----- Original Message ----
From: "Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp"
<Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp>
To: piping_valves@ yahoogroups. com
Sent: Wednesday, September 3, 2008 9:12:33 AM
Subject: Re: [piping_valves] Copper gasket.


Dear Yogesh,

Request you to indicate the following parameters please ...

1) Pressure Rating of the Flanges, in question;
2) Temperature of fluid, which will be wetting the flanges and gasket;
3) Name of fluid, which will be wetting the flanges and gasket;
4) Both flanges' facing details, like type, RF dimension, finish etc.

All these parameters are needed to do a quick check for the flanged joint's
integrity.
Guessing: What is the problem, if soft iron is used?

Kind Regards,
Bhatta.

yogesh modak
<yogeshm28@yahoo.
com> To
Sent by: piping_valves@ yahoogroups. com
piping_valves@ yah cc
oogroups.com
Subject
Re: [piping_valves] Copper gasket.
09/03/2008 01:22
AM


Please respond to
piping_valves@ yah
oogroups.com



At site on one of the flow meters flange facings of flowmeter flange and standard
piping flange do not match for the raise face dimension.


The raise face width at flowmeter end is less than standard flange. Hence
standard spiral wound gasket does not fit. Site came up with option of using
copper gasket. We enquired with gasket vendor and one of them said that copper is
not suitable for cyclic loading. He say's copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.

Also for copper, can we use standard bolt torque for tightening?

Regards

Yogesh _,___

locking devices

In continuation of the earlier email on the subject, the following companies are few prominent manufacturers.

http://www.smithflowcontrol.com/new/wheel-valves.htm

http://www.gst-systeme.de/Steuertechnik%20Download%20englisch.htm

http://www.netherlocks.com/

Check out the animation also.

With regards,
Kannan

Ball valve soft seat materials and temperature limitation

In general you may refer Table A323.4.3 of ASME B31.3

Bathula Raghuram

Ball valve soft seat materials and temperature limitation

This compilation done by Yayati-TICB. Source: Shell SPE.

Take note this is not an exahaustive list and various brands of PTFE does exist having different limits. So take the advice of the valve manufacturer before detailing your seat spec.

SEAT MATERIALS	Temperature range (deg.C)
Filled PTFE	-100	220
PEEK	-100	260
Modified PTFE	-200	200
EPDM	-20	110
VITON (fluoroelastomer)	-30	200
NEOPRENE	-20	85
NITRILE (NBR) (BUNA-N)	-10	100
STYRENE (SBR) (BUNA-S)	-40	70
NYLON POLYAMIDE	-40	90
ZYFLON	0	100
POLY OXY METHYLENE (POM)	-50	110
DEVLON -V (API GRADE)	-100	150
PER FLUOR ALKOXY (PFA)	-100	200
ETFE	-198	149
PCTFE	-250	150
VESPEL	-150	150

swapnil gorantiwar <gorantiwar_swapnil@yahoo.com> Sent by: piping_valves@yahoogroups.com 29/08/2008 10:20 Please respond to piping_valves@yahoogroups.com

To piping_valves@yahoogroups.com cc Subject [piping_valves] piping_valves

i want to know the temperature range of non-metallic seat material for ball valves. for which temperature range which non-metallic seat material is to be used in ball valves?   Regards, Swapnil Gorantiwar

.

__,_._,___

Finex and Corex furnaces.

As in the past we found few questions on furnaces and felt to add this to those messages.

Just today I read an interesting second page article in newspaper on Finex furnace which are new generation furnaces without ovens able to operate using fine coal instead of the traditional coking coal which is a high pollutant. Using this furnace the energy cost and pollution is reduced. And yet it does produce the pig iron suitable for high grade steels.

Posco with Siemens, then VAI has developed this in the past 10 years spending heavily and Posco's new plant in India and Vietnam are planned to be build with these Finex furnaces. This is a modification of Corex furnaces as per the article.

They claim the cost is reduced by 10% in overall and as the current fine coal price and coking coal price gap is increasing, they hope it should be more profitable in the coming years.

Good for Nature and Environment and in having a competitive steel price.

Regards,
Kannan.

PWHT by Induction Heating Method

I understand that in projects like Borouge, Ruwais the main construction contractor CCC is using and are prefering the induction heating.  As per my conversation the same as you have highlighted of the prefabrication spooling had been found to be more efficient and less time consuming and very acurate control of temperature, in comparision.

With regard to portability as per the contractor, they are using both portable and as well as fabrication shop stationed machine. It is available on lease by quite a no. of suppliers in the gulf region in particular. I havn't checked out the names of manufacturer nor the leasing agents, but can find out.

CCC also does have its own facility in the region in catering to various project sites of them. So in that sense it could be more efficient and cheaper solution on the run though the initial investment is high.

With regards,
Kannan



Dear members

Please share your experience on the subject method for pipe welds
(PWHT to be carried at site), one of our client insisting for
Induction heating instead of PWHT by conventional resistance coil
heating.

tho' i have seen literature on this I need info on availability (first
hand experience) of the equipment, portability etc..

I understand it is faster but advantageous in mass production, and may
not be easier for site activities. i don't see any reason for this
method over resistance heating

Raghuram Bathula

Material discrimination color.

The term is not used in our sector except in the shipping of our materials. Though I am much sure about it, to what I have once heard from a supplier that the containers are scanned like our baggage to know the content without opening, in specific to know if any internationally export  banned materials are shipped like radioactive elements etc. The scanner is capable of displaying in diff. colors the materials in the containers. Like steels, super alloys, rare metals in diff. colors. This caused the shippment delay which was how I came to know of it.

With regards,
Kannan


I have one query:what is mean by "Material descrimination color".Is it related to material identification using colors, like cs pipes with one color ss pipes with another color.

Sheetal Patil
Design Engineer(Piping)

Extended bonnet valves for high temperature service

Though such high temp valves do exist, but few in the plants and are specialized construction, due to the temp/press and service and the location of the valve and safety requirements.

The extended bonnet construction is one option to dissipate heat and to lower the heat at the stem packing similar to the reduction of cryogenic valve temp propagation to the stem packing and to avoid subsequent failure of the packing and operation of the valve. In all, the subject of concern is the stem packing failure. Other options are finned bonnet constr, stem packing with separate cooling system.

Protection for valve handwheel operation is not a major concern as it can be chosen as Motor/Pneumatic operated valve. Most of the hand operated valves requires once in a year operation in such high temp service.

Coming to the stem packing,
1)The usual ones are in one or more combination of graphite, metal rings, Elastomer rings, Lip seals, simple TEFLON rings etc.
2) In the moderately higher temp. range, only Graphite+alloy is used in diff. arrangements.
3) For very high temp such as your case, cooling system or the extended bonnets and same as 2) packings are used. Also many new proprietary packing arrangements are available in the market. Evaluating them is an important part of a material engineer's role.

Additional one to be noted is, the valve basic design is also to be reviewed. Process engr. is not a valve specialist. So the material engineer is supposed to evaluate such cases. In this case a rising stem valve type design to be avoided as it has vertical and rotation wearing on the packing. For controlling a butterfly valve could be evaluated. For Gate types, a knife gate valve could be thought of. Pl. take note that such evaluation has many things to be accounted for such as leakage allowance, emission, hazops, ATEX concerns, operation difficulty, trim erosion and not the least process parameters like pressure drops, zigma allowance, opening/closing period, service fluid etc.

Coming to your question,
1) Parameters controlling the bonnet height ...depends on the stem packing design and heat propagation to the packing. As a thumb rule for alloy constr. 250mm shall be the min. height.
2) On tests....apart from the usual tests, service condition test is required to be performed. But if the manufacturer has a prototype test certificate, it could be accepted. Again it depends on the application of the valve. In your case prototype should be OK, in my opinion.
3) Create these valves as special parts and specify the individual condition of operation and design to ensure correct valve/packing design is offered by manuf.

*****
Important note is the temp you specified and the valve material specified does not go well together. Being a HP steam and at 700 deg. c(which itself is very unusual), SS is no good and it has to high alloy grade. Or your design condition is to be verified. B16.34 defined the temp. limits in the notes of every rating table.
*****

Regards,
Kannan.


Dear friends

I have a query related to valves used at very high temperature for the refinery in Russia Im working on. The service are high temperature hydrocarbon, process with hydrogen or hot air and high pressure steam with ratings of 300# and 2500#. Design temperatures(stream list not yet issued by process) in FEED contractor piping class are 700 to 750 degC. Valve material(CF8, C>0.04)The FEED contactor has put a note against the valves(gate and globe) in his pipng class ' valves shall be supplied with extended bonnet and heat dissipating elements to obtain a packing temperature of 450degC maximum'. We have come across extended bonnet valves for cryogenic service.I would like to know if members have experience with extended bonnet valves for high temperature service. What are the parametres to be considered by the vendor in deciding the height of the bonnet? What are the tests/set up to be performed by the vendor to demonstrate that temperature at packing is <450°C.Is it feasible to have a extroordinarily long bonnet in order to maintain T<=450 deg C?? What are the other packing materials other than graphite that can be used to compensate for the height of the bonnet. line gaskets are spiral wound with SS304H windings and mica/graphite filler.

Regards
Shyam

Snamprogetti

Why 2000# threaded fitting are not covered in ASME B16.11

With ref. to your query on 2000 class fittings, I would like to highlight that those low pressure fittings have become more absolute in application.
Those fittings are finding very less use in low pressure drainage/sewer systems.

Answering yours and additional questions,

1) The 9000 lb fittings in NPT threading is beyond the permissible leakage allowance and so is why NPT threaded fittings are not available in that range. But other threading type can withstand higher pressure, which is how compression/threaded fittings work, like swagelok.

2) For 2000 lb fittings, socket welding is not available, as threaded fittings are sufficient enough for that pressure class. And socket welding such thin pipes is not economical/recommended due to the special care/skill required or the practical difficulty on alignment issues.

3) Cap & coupling were not convered in B16.11even when the MSS SP 49/50 was first encompassed into it and 4000 lb was eliminated due to the lack of support in the Americal industry. If you are using 2000 lb piping fitting, plugs are to be used against caps and unions against couplings.

Above all these, the most important fact to be considered is of the market trend and industry acceptance. For instance, min. pipe sch is STD / 2.24mm for 1/4". The pressure it can withstand is around 2000 lb discounting NPT threading. But it has become a practice to use 3000 lb and not 2000 lb.

Moreover to what I have seen, the prices difference is nearly nil between 3000 and 6000. 9000 is around 5 to 10 % higher than 6000. ofcourse it depends on the quantum you purchase.

Regards,
Kannan.


Dear all,

 could anyone explain that threaded fitting i.e. cap & coupling of class 2000  are covered in which standards?
 
because ASME B 16.11 , covered the forged threaded fitting (i.e. Tee, elbow and cross) of class 2000, 3000 and 6000.
But threaded cap,half coupling and coupling are covered from class 3000 and 6000.  
 
Regards,
Vinayak

Locking devices.

Very interesting note from Surve on CSO/C.

May be it would also be interesting to discuss on interlocking devices also at this point of time.

To the extend I have come across I would classify as below.

1) The normal valve locking devices which are used to have the valve locked in open or closed position on an individual basis.
2) The interlocked valve system where a group of valves are kept in open or closed position to achieve one or multiple different stream flow conditions in a chemical process.
3) The interlocked valve system where a group of valves in the upstream and downstream of one or group of Pressure Safety Valves for safety reasons.
4)  The interlocked valve system where a group of valves are kept in open or closed position and interlinked with electronic locking keys to obtain a swing in production of a plant like a switch between LLDPE to HDPE production based on the market demand and sales conditions.
5) The completely integral electronic interlocking system of valves to obtain a swing which are more sensitive and time framed.

The devices ranges from normal padlocks, integral locks in the valve design itself, external retrofit locking device and electronic locking devices using position sensors in campanion with MOVs.

The interlocking at times may involve as high as 30 different valves in one single network.

I find some companies apply the individual locking devices for PSVs, which is really not a safe solution. I feel the interlocking is required for PSVs so that even accidently the valves are not locked in wrong positions.  Moreover the Master keys are in the control of the plant manager and are obtainable only with proper authorisation for changing any of the valve positions. This is the same concept of CarSeal. This is one reason why we find very less engg. companies are prefering to have the above locking devices rather than the CarSeals.

The logics of locking operation are to be part of the Plant operating manual in my opinion. But rarely implimented.

Members who have used locking devices and systems for other purposes are also requested to share.

With regards,
Kannan