Does anyone recognize this P&ID Symbol? 1

[MattNCSU03]

I have scoured all of the P&ID legends I could find in-house and on the net and couldn't find a match for the attached symbol. It was received from a certain French steam turbine manufacturer and is located between the condenser hotwell and condensate pump suction isolation valve. My logical guess is that it is some sort of suction strainer, however, I would have located it between the pump isolation valves instead of upstream if that was the case.

Thanks!

 

[JohnBreen]

Errm.......maybe a tied expansion join???

JB

 

[pennpiper]

My guess is that symbol is a flexible joint (an expansion joint)
It would be considered premature to assume that an Expansion Joint (EJ) is required at the P&ID stage and it is not normal to include an EJ on a P&ID.

Ask the turbine vendor to verify that it is an EJ.
Then,
Ask them why they think one is required?

 

[JohnBreen]

perhaps a tied elastomeric (rubber) expansion joint??

look at this and other similar pages:

http://www.cadtoolsonline.com/rubberexp.html

Just add tie rods to these?

JB

 

[JJPellin]

I agree with the belief that this is an expansion joint. We would normally include this on the P&ID. But the location is not typical for our installations. We would always have an expansion joint between a condensing steam turbine and the surface condenser. But, I don't recall ever seeing one between the hot well and the pumps. Between the turbine and the surface condenser, there is a need to keep the pipe as short and straight as possible. An expansion joint is necessary. But, between the condenser and the pump, it would be more usual to make the piping flexible enough that an expansion joint would not be necessary.

Johnny Pellin

 

[JohnGP]

Me too, looks awfully like a tied expansion joint as suggested above, and also I'm with JJP - we have flexible joints all over our P&IDs, with their unique "special piping" item numbers.

 

[Thomasjl]

When I look to the symbol the first thing that comes up is an bellow with 2 rods to avoid overstretching.

I agree with JJPellin and JohnGP – Further a few things to consider.

Often bellows do appear on P&ID’s as they do effect the flow in the pipe.

P&ID’s are also often used for a (bulk) material take off, in that case all in line items are shown with their specific details. (This number 2110ZD could refer to that. Likely “ZD” stands for this thing in French, like EJ stands for “Expansion Joint” in English.)

Perhaps it is not a P&ID, some schemes look like a P&ID’s but they are just a schematic mechanical view (often used by vendors to show the working)

A bellow is not always an expansion joint, it is also used to avoid vibrations going from one system into another.

Thomas

 

[MattNCSU03]

Thanks for the suggestions! I tend to agree with the expansion joint theory. As to the label, the "Z" in "ZD" stands for miscellaneous, unfortunately the "D" (when preceded by a "Z" isn't defined in any of our equipment code sheets. I have a question in to the vendor, I'll let everyone know once and for all when I hear back.

 

[JLSeagull]

For instruments, Z is normally used for position.

 

[MattNCSU03]

Logically (or illogically perhaps), in this coding system, a position measurement is indicated by "MM"

 

[racookpe1978]

The expansion joints have to be regularly inspected and (less often) replaced during outages as the bellows material degrades.

So, to allow a isolation valve lineup/lock-out/tag-out to be written, the P&ID HAS to include all possible parts that might need to be isolated. (Otherwise, you're left rying to figure out "how/where/when do I isolate and drain and remove this thing - when I can't even see where it is on the P&ID?"

You will often see flanged joints on P&ID's for same reason: Where can I break the pipe? When I need to break the pipe, what do I have to isolate?

 

[DannyA]

This is certainly an expansion joint. Dependant on the orientation of the condenser relative to the LP Turbine, in a side condenser arrangement, expansion joints are required on CEP suction. On my current project,maximum design movement of hotwell is +6.1mm x-dirn. A factor of Safety is built in, resulting in sizeable expasion joints being required.
This is an additional feature to an expansion joint between LP Turbine Outer casing and Condenser neck, due to Steam Bypass nozzles directly feeding the condenser

 

[skearse]

We also use the "Z" to indicate position, with the following "D" that would then make this a "position device"-as for the symbol itself, no [original] ideas...I suppose I could buy-in to an EJ being considered as a "ZD" (amybe?).

 

[hydrae]

To present an alternative view

I have seen a 'inserted' valve that if it had a special PID symbol that would be it. It uses an oval hole in the pipe into which the gate slides into. The valve body is bolted around the pipe, then the oval is cut, cutter extracted and gate inserted, all done live.

I would think expansion joints would be the squiggly bellows like on the PID.

Hydrae

 

[JLSeagull]

Could it be a flame arrestor?

 

[MattNCSU03]

There is no combustion in the area so I don't think its a flame arrestor. Interesting idea Hydrae, I've seen some of the wild things companies can do with live pipes, however this is for a plant under design.

One additional note: This could be a drawing error but the third (and last) parallel pump does not show this symbol in line. Each pump takes suction from a common header. Still waiting to hear the official answer back from the vendor...

 

[StressGuy]

I concur with the group that the symbol is intended to be an expansion joint/isolator/flex coupling.

I also agree that it's the norm to show them on the P&ID's. We would categorize it as a "specialty item", as we would with spring supports, out of spec valves, strainers, etc.

Typically, if something is an "inline" specialty item, it shows on the P&ID as it's position relative to equipment, block valves, vents/drains and such needs to be known. Specialty items like spring supports would typically not be shown on a P&ID.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[SOROURA]

For Condensate Systems, sometimes it is preferable to have an expansion joint tied to the condensate pump's suction, not necessarily for thermal expansion (because condensate temperatures are around 38 to 40 degrees C), but because it isolates the vulnerable suction nozzle from line vibrations and transient effects.

It could also be useful during installation, because it gives the installer some tolerances during hook-up, especially since, in most cases, the Condensate Pump is of the vertical type, and relocating it is NEVER an option in case mismatches occur.

So it could be possible that the symbol resembles a tied expansion joint.

 

[MattNCSU03]

Its official, these are expansion joints. I'm not sure why they didn't use same symbol that they provided on their P&ID legend for expansion joint. Thanks for the input everyone!

 

[Gator]

Hydrae, are you talking about a stopple?