instrumentation Case Studies

GC Problems and Trouble shooting carried out at GCS Ramnad is described here.

Introduction

Now Normal Calibration done

But still total Un normalized concentration came very high

Consulted with Vendor After any change/repair/replacement etc it is mandatory to run 6-7 analysis with either calibration gas or sample gas(This is to purge the entire line properly.

Then Forced calibration to be done. And then normal calibration also to be done.

Now since existing Calibration gas exhausted, new calibration cylinder connected.(Calibration gas should not be used below 3 kg/cm2)

Changed component data table. And normal calib done. Excess RF Deviation alarm came.

Again RT Changed in Component data table and forced calibration done. After that normal calibration done. Now repeatability check carried out.

Repeatability OK.

Put in continuous analysis mode

07.04.2011

GC all parameters are normal Joint calibration Carried out and taken online.

Conclusions:

1. Any reduction in Sample flow rate is due to Chocking in either Sample probe/ sample line/ Genie filter/ Nupro filter Six Port Valve/Analyser Coloum(Low Probability)
2. In first case clean it/Purge it/ replace filter
3. In the second case rebuild six port valve(use aceton or fast evaporating cleaning Agent)
4. Bridge Balancing to be done.
5. Base line run to be done
6. Forced Calibration to be done followed by Normal calibration.

Please feel free to comment on this case

Regards.
C Vinod, DySE(E&T), GCS Ramnad 19.04.2011

Problem:

The operation of Shutdown valve at KVK GCS SDV101 is completely stuck up and was given for service to CE Valves.

And the operation of SDV102 (after service of actuator assembly at site) was observed to be opening in two or three strokes and not smooth.

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Update:

Last week the shut down valve (SDV101) was received after service from CE valves and checked.

After service the valve could be operated manually with handwheel. (was bit tight)

With actuator the 90 degree opening and closing rotation was observed to be occuring in two or three strokes in a slow motion with pauses in between.

Please advice.

_____________________________________________________

Operation: 

Shutdown valve has a Gear box mounted, a pneumatic cylinder and two spring assemblies at the ends.

Two ports are available in the cylinder body for charging/discharging of pneumatic supply to the cylinder.

One port is connected to center (between discs) of cylinder and another to the both ends (rear to the discs) of the cylinder.

For opening of valve air is charged between two discs mounted to the central shaft which is moving outward and air is discharged from rear end of the discs. 

For closing of valve air is charged to rear of the disc and air charged between the disc is discharged.

This charging and discharging is done via 5 port solenoid valve assembly.

Note: Pics of Shutdown valve actuator is uploaded to media gallery.

Advantages of a PC Based HART Communicator

Introduction

It’s now time to upgrade to a new HART Communicator. Your old hand held HART
Communicator is obsolete and receives limited support. You shop around and find that it
costs between $3000 and $7000 for a new hand held HART Communicator. A Google
search reveals a PC based alternative. Will the PC alternative perform as required? What
should you look for?

The PC based HART Communicator has been around for many years, but until recently it
has not been able to replace the hand held HART communicator. The main reason is that
it could not communicate at the DD level with all the devices in the DD library. Recent
developments have eliminated that problem and now is a good time to review the
capabilities of a PC based HART Communicator.

Device Descriptions (DD’s) and the SDC-625

The key criterion is that the program must be “DD based”. This means the software uses
the HART Device’s DD object file to present menus, variables, and methods. The device
manufacture spent a considerable amount of time developing the DD so that the full
functionality of the device is available to the user. The DD was tested extensively for
release to the HART Foundation DD Library. This DD is the only approved way to
interface to a HART device. Some programs use files that are derived from the DD.
However, this approach is not safe because the device manufacture does not test the
derived files. Only the compiled DD binary file is tested by the device manufacture.

The HART Communication Foundation (HCF) recognized the need for a standard PC
based interface into the DD. They applied their expertise into the standard and in 2004
released the SDC-625 Smart Device Communicator. The SDC-625 uses the DD binary
files just like the hand held HART communicator. An SDC-625 developers group was
created, where member companies had access to the source code and could improve the
software. All developer companies get access to the improved code, so the quality and
functionality increases rapidly. This open source method of software development is
quickly becoming a standard practice for software creation worldwide.
A new requirement by the HART Foundation is that all new DD’s must pass a testing
protocol using the SDC-625. This ensures all DD’s are bug free and behave as expected.
So any PC based communicator that is built using the SDC-625 is also guaranteed to
work as the device manufacture intends.
Ease of Updating
Once you have established that the candidate PC based HART Communicator is DD
based, you can look deeper into other criteria. One is the DD Library itself. The DD
Library is updated 4 times per year by the HART Communication Foundation (HCF).
Does the software contain all devices released by the HART Foundation? Is it easy (and
inexpensive) to update the library? Some hand held HART communicators are extremely
difficult and expensive to update. PC Based HART Communicators can take advantage
of the internet to maintain the library.
Ease of Use
A very important advantage of a PC based HART communicator is that it has much more
screen space to display information. The menu structure of the DD can be expanded or
contracted as required. This enables you to jump directly to the information or function
you are interested in. No more digging through menus to perform a task, then
backtracking to the main menu to then dig down another path to do something else. In
the PC communicator everything is available at a glance. With a full keyboard available,
data entry is also much improved.

The Windows interface is known to everyone worldwide. Training time is thus greatly
reduced. Menus allow functions to be readily available – again, no need to dig through
pages of menus to find what you want.
Single Function vs. Multi-function
Hand held HART Communicators can only perform one function - HART
Communications. A PC based solution offers the advantage of having all your needs met
with one tool: Email, user manuals, operating procedures, reports, contact database, etc.
are all available on your PC. In fact HART Communications on your PC allows
integrating the HART information easily into your report database, contact management,
and email. This results in higher productivity for the engineer or instrument technician,
and also eliminates one extra piece of equipment.
Device Configurations
Documenting and managing device configurations are other important criteria. Some
hand held HART communicators have memory limitations that limit the number of
configurations you can save. Also, it may be difficult or impossible to transfer the
configurations to the PC for archiving or viewing. PC based communicators have no
practical memory limits. Configurations can be saved and viewed using standard
programs. In a PC based communicator, make sure the saved configurations can be
viewed in a user friendly way. PDF files make great looking reports possible.
Customizable reports are also a nice touch.

Size and Mobility, Bluetooth as a Solution
In the past it was difficult to use a PC based HART communicator in hard to reach
places. Carrying a laptop up a ladder is dangerous. However, now there are Bluetooth
based HART modems that provide great convenience. Connect the Bluetooth HART
modem in the hard to reach location, and then climb back down to safety and use your PC
based HART communicator safely from the ground.
Conclusion
With the advent of the SDC-625, full featured PC based HART Communicators are now
a reality. The SDC-625 uses the DD binary files supplied by the device manufacturer.
The DevCom2000 Smart Device Communicator software from ProComSol, Ltd is based
on the SDC-625 software from the HART Communication Foundation. It was released
in 2007 and has benefited from the open source development process and from user
feedback. It is now feature rich, stable, and reliable. It offers full configuration saving
and download. Configuration reports are easy to read and distribute via PDF files that are
customizable. It can be used with either HART USB modems or HART Bluetooth
modems, and the DD Library is easy to update.
The DevCom2000 Smart Device Communicator is a PC based HART Communicator that
offers many advantages over hand held communicators: ease of updating, ease of use,
multi-function capability, ability to document and manage device configurations, and
most importantly – significant cost savings.

ProComSol, Ltd Contact:
Michael B. Fersky, Marketing Manager

Please see the image of LSL-107 float deformation.What might be the reason for such deformation? Here are the vessel details

V-107  (TEST OIL STABILISER) The vessel is operating at 2.5 kg/cm2 and design pressure is 3.5 kg/cm2

Online GC Vis-a-Vis Offline Gas Analysis

Introduction

By installing an Online GC, these disadvantages will be taken care. Here Analysis will be done every fixed Interval(eg. 4 minutes cycle) and the result will be directly communicated to Flow computer on a real time basis. Hence the accuracy of Flow measurement will be very high