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butterfly valve 1
- Thread starter Lucycn
- Start date
- Thread starter
- #3
Hi anegri,
Thanks for your explanation, I have the same feeling for the one flanged end, but I received a questionary, it list 4 types of Double Eccentric butterfly valve ( Wafer, Lug, Flanged and Double flanged), 5 types of Central line (Wafer, Lug, Flanged, Double flanged and Metal-Metal) 3 types of Triple Eccentric, Dose it have different?
Thanks for your explanation, I have the same feeling for the one flanged end, but I received a questionary, it list 4 types of Double Eccentric butterfly valve ( Wafer, Lug, Flanged and Double flanged), 5 types of Central line (Wafer, Lug, Flanged, Double flanged and Metal-Metal) 3 types of Triple Eccentric, Dose it have different?
Lucy,
my feeling is that the questionary refers to the products range of a specific valve Manufacturer. In fact, while "Wafer, Lug, Flanged and Double flanged" regard valve ends, "Metal-Metal" regards valve seat... and I know, for example, that exist Manufacturers whot produce metal-seated triple-eccentric butterfly valves only, but in all types of end connections.
So I don't know what the difference between "Flanged" and "Double flanged", in this case, could be; of course, I'd suggest to ask the Author of the questionary, if possible.
Ciao, 'NGL
my feeling is that the questionary refers to the products range of a specific valve Manufacturer. In fact, while "Wafer, Lug, Flanged and Double flanged" regard valve ends, "Metal-Metal" regards valve seat... and I know, for example, that exist Manufacturers whot produce metal-seated triple-eccentric butterfly valves only, but in all types of end connections.
So I don't know what the difference between "Flanged" and "Double flanged", in this case, could be; of course, I'd suggest to ask the Author of the questionary, if possible.
Ciao, 'NGL
- Thread starter
- #5
Hi Anegri,
Thanks for your clear division,as you mentioned you knew the exist manufacturers who product all types of end connection of metal seated triple-eccentric butterfly valve. does it has other types of end connection except Wafer, Lug and Flanged? does it has the rubber seated of triple-eccentric butterfly valve? or only metal seated triple-enccentric butterfly valve existed?
Thanks for your clear division,as you mentioned you knew the exist manufacturers who product all types of end connection of metal seated triple-eccentric butterfly valve. does it has other types of end connection except Wafer, Lug and Flanged? does it has the rubber seated of triple-eccentric butterfly valve? or only metal seated triple-enccentric butterfly valve existed?
tsenthil
Mechanical
- Mar 13, 2003
- 41
Most of the triple eccentric Butterfly Valves are metal seated (I Saw some eccentric valves with PTFE seat). This is because Triple Eccentric Butterfly Valves are primarly used in High Pressure and High Temperature areas where operating torque of Valves are more.
Flanged end and Lug end valves are same.
Senthil
Flanged end and Lug end valves are same.
Senthil
Both mean the same. However, "double flanged" is commonly used in the butterfly valve industry to distinguish between the normal "double flanged" valve (two flanges, one on either side) from the "lug-type" which has a "single flange" in the center.
- Thread starter
- #8
Hi tsenthil,
Thanks very much for your response, Yes, Most triple eccentric butterfly valve is metal seated, does it can be no leakage? How about the PTFE seated? did you see some eccentric valve using a pack of blade of steel and graphite on the disc or on the body to guarantee the absolute and perfect sealing?
You mean "Flanged end and Lug end are same valve" But "Double flanged end should be different with Lug end"?
Thanks in advance.
Thanks very much for your response, Yes, Most triple eccentric butterfly valve is metal seated, does it can be no leakage? How about the PTFE seated? did you see some eccentric valve using a pack of blade of steel and graphite on the disc or on the body to guarantee the absolute and perfect sealing?
You mean "Flanged end and Lug end are same valve" But "Double flanged end should be different with Lug end"?
Thanks in advance.
- Thread starter
- #9
tsenthil
Mechanical
- Mar 13, 2003
- 41
1. Some valves like Durco BX6 Series Metal seated valves meet ANSI FCI 70-2 Class VI leakage.
2. Normally all PTFE Seated valves are Class VI Tight Shut Off valves.
3. Double Flanged and Lug (Flanged) Valves are different. Double Flange has two flanged on both edges of valve body whereas Lug type is having single flange in the center of valve body.
Normally Valves designed in AWWA standards are Double flanged type. This valves are very large in size (above 900mm to 2000mm) mainly used in cross country water pipelines.
Flanged or Lug type valves are manufactures as per API609 or BS5155 and normally sizes varies from 50mm to 700mm.
Lucy:
I dont know about valves you have mentioned Graphite etc., but Generally Metal Seated Butterfly Dampers are with Inconel or SS Seats and they achieve 100% Sealing by using a Seal Air Fan.
Generally Graphites are used as Seals if the valves are Fire Safe in design.
Thanks
Senthil
2. Normally all PTFE Seated valves are Class VI Tight Shut Off valves.
3. Double Flanged and Lug (Flanged) Valves are different. Double Flange has two flanged on both edges of valve body whereas Lug type is having single flange in the center of valve body.
Normally Valves designed in AWWA standards are Double flanged type. This valves are very large in size (above 900mm to 2000mm) mainly used in cross country water pipelines.
Flanged or Lug type valves are manufactures as per API609 or BS5155 and normally sizes varies from 50mm to 700mm.
Lucy:
I dont know about valves you have mentioned Graphite etc., but Generally Metal Seated Butterfly Dampers are with Inconel or SS Seats and they achieve 100% Sealing by using a Seal Air Fan.
Generally Graphites are used as Seals if the valves are Fire Safe in design.
Thanks
Senthil
- Thread starter
- #11
Hi Senthil,
Thanks a lot for your reply.
1. I am not familiar with Durco BX6 series valve, where can I find it? what types does it belong to?
2. what different between PTFE seated and EPDM seated valve? Do I distinguish it only from different appliciation? does their different has other meaning?
3.the flange thickness of AWWA standard usual is thicker than DIN standard. what different it is in appliciation?
I just heard of the valve using a pack of blade
of steel and graphite on the disk or on the body to guarantee the absolute and perfect sealing. but I never seen it.
Thanks a lot for your reply.
1. I am not familiar with Durco BX6 series valve, where can I find it? what types does it belong to?
2. what different between PTFE seated and EPDM seated valve? Do I distinguish it only from different appliciation? does their different has other meaning?
3.the flange thickness of AWWA standard usual is thicker than DIN standard. what different it is in appliciation?
I just heard of the valve using a pack of blade
of steel and graphite on the disk or on the body to guarantee the absolute and perfect sealing. but I never seen it.
Lucy,
as far as I know, rubber seated butterfly valves have usually single- or double-eccentric design and are usually used in water services (or similar), while triple-eccentric ones are usually metal seated. "Metal seated", however, does not exclude the presence of "soft" parts where graphite (or PTFE, depending on service conditions) is present: spiral wound gaskets, stem packing and seal.
Many triple-offset metal-to-metal valves (like Vanessa Series 30,000 by Tyco, for example) have a seal ring mounted on the disc and the seat on the body, hard faced with Stellite, Inconel, Ultimet, etc.; the seal ring is usually of a lamellar type, i.e. made of alternate lamellas of metal and graphite (or PTFE). Depending on the service conditions (high temperature, solid particles, etc.) a "solid", all-metal seal ring is also used. Both can achieve very good sealing performances, such as "Class VI" for control valves or "Zero Leakage" (even if this expression should be avoided: see Thread408-22293).
Hope this can be useful... Bye, 'NGL
as far as I know, rubber seated butterfly valves have usually single- or double-eccentric design and are usually used in water services (or similar), while triple-eccentric ones are usually metal seated. "Metal seated", however, does not exclude the presence of "soft" parts where graphite (or PTFE, depending on service conditions) is present: spiral wound gaskets, stem packing and seal.
Many triple-offset metal-to-metal valves (like Vanessa Series 30,000 by Tyco, for example) have a seal ring mounted on the disc and the seat on the body, hard faced with Stellite, Inconel, Ultimet, etc.; the seal ring is usually of a lamellar type, i.e. made of alternate lamellas of metal and graphite (or PTFE). Depending on the service conditions (high temperature, solid particles, etc.) a "solid", all-metal seal ring is also used. Both can achieve very good sealing performances, such as "Class VI" for control valves or "Zero Leakage" (even if this expression should be avoided: see Thread408-22293).
Hope this can be useful... Bye, 'NGL
- Thread starter
- #13
Hi anegri,
Thanks very much for your explanation.
Dose rubber seated butterfly valve is only usded in water services and similar? can you tell me more about "similar"? Dose triple-eccentric metal seated can be used in more application?
Dose triple-eccentric is the same definition with triple-offset? or difference?
Your explanation about seal ring of triple-offset M-M valve(like valve by Tyco,for example or like valve by Adams, for example maybe) is clearly and very useful for me, even I never seen but I think I can understand what you said, and it is also same with my customer explain to me.
Thanks again.
Thanks very much for your explanation.
Dose rubber seated butterfly valve is only usded in water services and similar? can you tell me more about "similar"? Dose triple-eccentric metal seated can be used in more application?
Dose triple-eccentric is the same definition with triple-offset? or difference?
Your explanation about seal ring of triple-offset M-M valve(like valve by Tyco,for example or like valve by Adams, for example maybe) is clearly and very useful for me, even I never seen but I think I can understand what you said, and it is also same with my customer explain to me.
Thanks again.
Lucy,
rubber-lined valves, of course, have more thermal and chemical limits, but I don't know many applications, more then water related ones.
Metal-to-metal valves, instead, are fire-safe and can be configured for many services (in the chemical, geothermal, food, mining, water, power generation, oil and gas industries...).
Yes, for me "triple offset" is the same as "triple eccentric".
Maybe the following links can be useful for your information, just to see some images of this type of valves:
* * * * Best regards, 'NGL
rubber-lined valves, of course, have more thermal and chemical limits, but I don't know many applications, more then water related ones.
Metal-to-metal valves, instead, are fire-safe and can be configured for many services (in the chemical, geothermal, food, mining, water, power generation, oil and gas industries...).
Yes, for me "triple offset" is the same as "triple eccentric".
Maybe the following links can be useful for your information, just to see some images of this type of valves:
* * * * Best regards, 'NGL
Lucy:
Your initial question about the flanging seems to have exploded to many other subjects. I will try to give you answers to whatever I remember from the above thread...
Re. flanged and double flanged concept. This means the same thing, i.e. the valve has a flange at each end. A specifically single flanged valve is generally considered a lug type valve. Lugs are typically tapped to allow the valve to be bolted between the pipe flanges from both ends. I have come on ocassion across a spec that described a single flanged valve as a valve with lug body, but drilled through, not tapped, which functioned as a wafer body, but still allowed simple bolting to a dead end without a redundant downstream flange.
Re. differences between flanged (i.e. double flanged) and a lug or wafer. Here you have to be careful, the laying length i.e. face to face dimension of a flanged valve is significantly wider than of a lug or a wafer valve.
Re. rubber seated, metal seated, Teflon seated, graphite laminates, etc. butterfly valves. These are all very different animals, for different applications, and the costs differ significantly.
Commercial type rubber seated BFV would be the low cost end and a metal seated triple offset valve like the one with the stainless and graphite laminated disc seal you mentioned above, would be on the high end of the price ladder.
However, the applications of these valves can overlap, so your selection should, amongst other, be governed by cost considerations. Generally, rubber seated valves are good for low pressure (250 psi max) service, and low temperature (300 F max) for very vast selection of flow media, depending on what rubber is used.
Teflon lined valves can either be plain zero offset valves same as the rubber seated valves, except these valves are suitable for more corrosive service than rubber seated valves; or they can be double offset or even triple offset hi-performance valves for higher pressure and higher temperature service. Pressure is more or less unlimited, and temperature is limited to somewhere between 400 and 500 F, depending on the fill in the Teflon material.
Metal seated butterfly valves can be either damper type (somebody mentioned) with leakage rate varied usually by the valve size (very difficult to get a small damper to conform to a low leakage rate); or metal seated valves can be double or triple offset type. Double offset metal seated valves are usually used together with Teflon seats and are the so-called common fire safe hi-performance valves. Triple offset metal seated valves are of various construction, but in most cases, use a laminated seal ring, either on the disc or in the body, to seal against very high temperatures and very high pressures. Triple offset metal seated valves are inherently fire safe, and inherently cryogenic (with neck extension). Contrary to what was stated by someone above about class VI leakage rates, reputable manufacturers produce triple offset metal seated valves to perfect bubble tight seal. Triple offset valves are normally not used in corrosive applications, and would be an overkill in a plain water application. Typically, high temperature service like steam would be the common use for triple offset BFVs.
Well, I hope this is enough for now...
Good Luck...
Your initial question about the flanging seems to have exploded to many other subjects. I will try to give you answers to whatever I remember from the above thread...
Re. flanged and double flanged concept. This means the same thing, i.e. the valve has a flange at each end. A specifically single flanged valve is generally considered a lug type valve. Lugs are typically tapped to allow the valve to be bolted between the pipe flanges from both ends. I have come on ocassion across a spec that described a single flanged valve as a valve with lug body, but drilled through, not tapped, which functioned as a wafer body, but still allowed simple bolting to a dead end without a redundant downstream flange.
Re. differences between flanged (i.e. double flanged) and a lug or wafer. Here you have to be careful, the laying length i.e. face to face dimension of a flanged valve is significantly wider than of a lug or a wafer valve.
Re. rubber seated, metal seated, Teflon seated, graphite laminates, etc. butterfly valves. These are all very different animals, for different applications, and the costs differ significantly.
Commercial type rubber seated BFV would be the low cost end and a metal seated triple offset valve like the one with the stainless and graphite laminated disc seal you mentioned above, would be on the high end of the price ladder.
However, the applications of these valves can overlap, so your selection should, amongst other, be governed by cost considerations. Generally, rubber seated valves are good for low pressure (250 psi max) service, and low temperature (300 F max) for very vast selection of flow media, depending on what rubber is used.
Teflon lined valves can either be plain zero offset valves same as the rubber seated valves, except these valves are suitable for more corrosive service than rubber seated valves; or they can be double offset or even triple offset hi-performance valves for higher pressure and higher temperature service. Pressure is more or less unlimited, and temperature is limited to somewhere between 400 and 500 F, depending on the fill in the Teflon material.
Metal seated butterfly valves can be either damper type (somebody mentioned) with leakage rate varied usually by the valve size (very difficult to get a small damper to conform to a low leakage rate); or metal seated valves can be double or triple offset type. Double offset metal seated valves are usually used together with Teflon seats and are the so-called common fire safe hi-performance valves. Triple offset metal seated valves are of various construction, but in most cases, use a laminated seal ring, either on the disc or in the body, to seal against very high temperatures and very high pressures. Triple offset metal seated valves are inherently fire safe, and inherently cryogenic (with neck extension). Contrary to what was stated by someone above about class VI leakage rates, reputable manufacturers produce triple offset metal seated valves to perfect bubble tight seal. Triple offset valves are normally not used in corrosive applications, and would be an overkill in a plain water application. Typically, high temperature service like steam would be the common use for triple offset BFVs.
Well, I hope this is enough for now...
Good Luck...
- Thread starter
- #17
- Thread starter
- #18
Hi anegri,
Thanks for your further explanation for rubber seated and metal seated valve. I have another question about metal seated valve. As you mentioned, metal-to-metal valve is fire-safe can be configured many service. Do all Metal-to-metal valves are fire-safe? what's meaning of fire-safe? if all metal-to-metal seated valves are fire-safe, why my customer must require me to provide fire-safe certification?How can I get this certification?
Thanks a lot, wish my question does not beyond our topic.
Thanks for your further explanation for rubber seated and metal seated valve. I have another question about metal seated valve. As you mentioned, metal-to-metal valve is fire-safe can be configured many service. Do all Metal-to-metal valves are fire-safe? what's meaning of fire-safe? if all metal-to-metal seated valves are fire-safe, why my customer must require me to provide fire-safe certification?How can I get this certification?
Thanks a lot, wish my question does not beyond our topic.
- Thread starter
- #19
Hi hmmmmm,
Thanks very much for your browse all of our comments to give me your idea about my initial question.
1. flanged and double flanged. yes your explain make me more clear of it, but I still have a question from your answer, what's different from drilled through and tapped? as I understand whether drilled through is usual used in bigger size, tapped used in the small size? if for high pressure i.e. PN40 and up, whether flanged (lug type) can not support valve sometimes? so the double flanged maybe better?
2. yes double flanged face to face dimension is wider than lug and wafer valve. how can I to distinguish them? as I know for centre butterfly valve is lug and wafer valve, for eccentric( double or triple) is more double flanged (some times is wafer)but for bigger size almost all of them are double flanged. what are they different? just from cost and application? how can I suggest to use eccentric valve to instead of center valve( in what condition can I suggest)?
3.if triple offset metal seated valves are inherently fire-safe? Do I need to provide the certification of fire-safe for my customer? How can I get this certification? as the same question I mensioned above?
4. does the bubble tight is the same meaning with no leakage? what's different of them?
5. Now I am clear of the use of Rubber seated Teflon seated and Metal seated butterfly valve.
Thanks again.
Thanks very much for your browse all of our comments to give me your idea about my initial question.
1. flanged and double flanged. yes your explain make me more clear of it, but I still have a question from your answer, what's different from drilled through and tapped? as I understand whether drilled through is usual used in bigger size, tapped used in the small size? if for high pressure i.e. PN40 and up, whether flanged (lug type) can not support valve sometimes? so the double flanged maybe better?
2. yes double flanged face to face dimension is wider than lug and wafer valve. how can I to distinguish them? as I know for centre butterfly valve is lug and wafer valve, for eccentric( double or triple) is more double flanged (some times is wafer)but for bigger size almost all of them are double flanged. what are they different? just from cost and application? how can I suggest to use eccentric valve to instead of center valve( in what condition can I suggest)?
3.if triple offset metal seated valves are inherently fire-safe? Do I need to provide the certification of fire-safe for my customer? How can I get this certification? as the same question I mensioned above?
4. does the bubble tight is the same meaning with no leakage? what's different of them?
5. Now I am clear of the use of Rubber seated Teflon seated and Metal seated butterfly valve.
Thanks again.
Lucy,
as you can probably see by looking into the above mentioned websites, usually Manufacturers are already fire-proof certified, that is they have already performed "prototype" fire testing on a set of valves able to qualify a certain products range. Otherwise, they can perform fire tests upon Customer's requests, for single projects... so, of course, I suggest you hear from your Manufacturer to get certification.
The usual reference standards are API 607 (this is intended for rubber-seated butterfly valves with a certain maxmum allowable leakage, but it can be also extended to metal-seated ones by accepting "no visible leakage" only, for example) or similar API 6FA and ISO 10497.
lms1964,
about achieving triple-eccentric geometry, I think that the first two offsets regard the shaft axis, while the third is provided by the conical machining of the seat on the body.
Bye, 'NGL
as you can probably see by looking into the above mentioned websites, usually Manufacturers are already fire-proof certified, that is they have already performed "prototype" fire testing on a set of valves able to qualify a certain products range. Otherwise, they can perform fire tests upon Customer's requests, for single projects... so, of course, I suggest you hear from your Manufacturer to get certification.
The usual reference standards are API 607 (this is intended for rubber-seated butterfly valves with a certain maxmum allowable leakage, but it can be also extended to metal-seated ones by accepting "no visible leakage" only, for example) or similar API 6FA and ISO 10497.
lms1964,
about achieving triple-eccentric geometry, I think that the first two offsets regard the shaft axis, while the third is provided by the conical machining of the seat on the body.
Bye, 'NGL
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