Why automated valve of ON OFF type and ESDV type are categorized as instruments by most users

[anand25111987]

Hello,

Can some one enlighten me on this question. An Instrument is a device to record,measure or identify any entity. A ON OFF or ESDV valve is not desired to perform any of the mentioned functions. A relief valve can be categorized as instrument.Whereas a linear and rotary ESDV and ON OFF valve is completely a mechanical device automated by any of the power operator(pneumatic,electric or gear). The function of the ESDV assembly is still the same as a manual valve except it is automated. I have the same question with control valve also. Should this be a instrument

Thanks and Regards,
AP

 

[LittleInch]

I hope some others come on here and provide an historical input because I've never worked it out either. I can only suspect that because it involves signals, wires and in decades past wholly pneumatic systems and relays that the mechanical engineers didn't want it and it just "fell" into instrumentation.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[pennpiper]

anand25111987,
A simple answer is, "People can call it what ever they want to".

A more complex answer is, both of the examples valves you site are controlled remotely by sensors that "read" a specific condition, therefore are part of an instrumentation circuit and receive an instrument tag number.

Sometimes its possible to do all the right things and still get bad results

 

[anand25111987]

Hi Little Inch,

Yes I agree as per my knowledge I could not see any other reasons other than what you mentioned on why it fell into instrumentation. But having it classified under instruments questions the fundamentals of the definition.

 

[anand25111987]

Hi Pennpiper,

The sensors that read a specific condition are completely a different subject and not in general fall under the ESDV vendor scope OR ESDV user instrumentation team

Thanks AP

 

[Roberto1956]

Easy answer for you. SDV, BDV and any on-off valve that receive an actuator goes to Instrument Departure of Engineering while the manual valves are in Pipeline Department. This is not exact your company but I believe it is similar. Instrumentation People are used with really control valves used in process to control pressure and so on. There are valves that do not need to be tight. This may bring some problems as the use of ANSI FCI 70-2 as the tight test so very different of API 598. So this is a internal problem because the mechanical valve is the same, the function is the same unless that now it has an actuator instead of an operator with a walkie-talkie closing or opening the valve by hand.

 

[MickMc]

As previous responses have indicated typically the demarcation is manual (piping) or control (instrumentation) and for block valves the piping valve is normally common for both with actuator added for instrumentation in lieu of handwheel/gear operator. For regulating valves there may be different spec regarding cage trim but body and trim material should follow piping valve and I would expect that the piping material engineer would review all instrument valve data sheets etc to confirm compliance.

As for tightness tests this is always grey area but in my opinion all block valves should follow the more stringent API 598 or equivelant and the regulating valves the less stringent FCI 70-2 but this can be difficult to enforce as typically the thinking is follow piping or instrumentation codes rather than function.

 

[anand25111987]

Dear Roberto and Mick,

Thanks for your response. I also got this clarified here. A manual ON OFF valve performs a ON and OFF function which blocks/opens the line It does not give any feedback to the DCS. However ESDV,automated ON OFF valve and control valve lines valve position are constantly monitored by the DCS system . These valves give information to the DCS whether the line is open or close . Hence these are classified as instruments. A mechanical device with addition of positioner, switch box is used as a instrument.

Thanks and Regards,
AP

 

[gerhardl]

I have seen above discussion just now.

Let me add following: We are here discussing the border limit (almost always) between two 'departments'. Thread carefully! Very often someone fall in the ditch between theese two borderfences: things are not clarified or discussed in detail until it is to late, signal equipment from on/off valves (more often now than before) are not taken into account, 'I thought the instrument department should have described necessary signal (additional box) from the actuator, etc. etc.

The art is to get all detailed signals and steering parameters down on paper early in the project, then you split the respnnsibillity.

A try for general categorizing will help, but might also cause misunderstandings.

(Everything seems to be taken care of for your project!)

 

[moltenmetal]

We consider all automated valves to be instruments, whether they are control valves or on/off XVs, because they share one thing in common: they're connected to either the control system (DCS) or ESD system.

We don't stop at the solenoid or the switches- the valve and its actuator are included.

If a valve has an actuator not connected to the control system merely for the convenience of the operator due to location, size etc., then we can argue a little more.