How to Determine the Best Field Instruments for Awesome Results?

 I warn you that this post is long and maybe you don't have time or in the right places and circumstances to read this, so I'm  going to give you this sign before I start (so you're not going to sue me for this)

Hahahaha. I love it. OK now what? Oh yes.

How to determine what instrument is best for your application?

Well, It require very intense experience to do that. You know it when you have made mistakes and have a change to correct them. Only by facing the problems you can appreciate the impact of instrument selection, documentation, and installation on its serviceability.

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Warning! This blog is Boring

The author warns you that this technical blog is long, tired and you're at risk of falling sleep ( I fell a sleep while proofreading this blog). I would recommend you not to read this blog while you're

1. Working at heights

2. Operate Heavy Machinery

The Real Engineering Project Interaction

Project Manager: Okay guys, lets make an unmanned technologically advanced plants that are safe with high yield and LOW COST  in less than a year( with a little number of engineer, no support groups (drafting, computer services, purchasing, etc) and a large number of managers).

Process Engineer: We need you to calculate and design a control valve with the  40 barg pressure drop in 2" line pipe under the choked flow condition.

Mechanical Engineer: We managed to purchase low cost packaged equipment without any electrical drawing, Could you make the shop drawing for us?

Electrical Engineer: We want to put electrical heat tracing on the UPS.

Piping Engineer: We forgot to isolate the pressure transmitter during hydrotest.

Safety Engineer: We want to put water sprinkles in the control room because its cheaper

Instrument Engineer: Arrrrrrrrggggggggggggghhhhhhhhhhh

Orang-Orang yang mencintai Ilmu (Cerita Dr Abdus Salam Dengan Pelajar Jerman)

Disadur dari buku Dr Abdus Salam Poor As A Nation.

Dr Abdus Salam: Orang bilang kemiskinan adalah musibah karena jika sesorang lapar dia tidak punya waktu dan keinginan untuk belajar mengasah kemampuan otaknya. Saya selalu teringat sebuah kejadian di Jerman sekitar 40 tahun yang lalu mengenai masalah ini.

Pada tahun 1947 saya adalah mahasiswa di Universitas Cambridge, Jerman sudah kalah perang saat itu dan seluruh masyarakat jerman sedang merasakan penderitaan karena kekalahan ini.American Control Commission mengundang mahasiswa dari Cambridge dan seluruh Eropa untuk melihat penderitaan yang sedang masyarakat Jerman rasakan.Sekitar 500 orang mahasiswa datang ke Munich dari seluruh Eropa.Saya lihat tidak ada satu gedungpun yang masih berdiri utuh dan sepertinya penduduk munich harus tinggal pengungsian.

Pump control and valves 2

Bud (the senior instrument engineer) and Bob (the new instrument engineer) were on the trip to automate the start-up of the new  water injection pump. They caught people's attention because they were wearing coverall clothes and carrying their hardhats on their way from the hotel to the plant. 

Bob: Wow, Bud, I wonder what would happen on this start-up. I think it would be great since the simulations you did showed the stuff would work just fine.

Bud: Bob, anything can go wrong in the start-up. There is plenty that can go wrong with this system. The new control system must control the new water injection pump because the existing 2x100% water injection pumps only have design flow rate if 30,000 BWPD. but the actual produced water flows in excess of the 60,000 BWPD. So we need a third one and the pumps will be operated 3x50%. There is a level controller of the of the produced water vessel to control  a downstream control valve . Valve travel would have effect on the flowrate, This could result erratic control with poor stability and accuracy.

Pump controls and valves

The vice president of the company Mr Big boss just came to his plant for site visit and watch the plant performances and production personally.  The plant manager asked Bud (the instrument engineer) to escort Mr Big boss around the factory with him. The Big boss saw one of the pump operated and asked the plant manager what is it

Big boss: What is this thing called? This stuff is make a lot of noise and vibration.

Plant manager: This is pump boss. Pumps are used in the production facilities to move liquid from a low pressure/elevation to one of higher pressure or elevation.

Big boss: How this thing works?

Control Valve operation and design criteria for beginners 3

In process systems, the final control element is normally a pneumatically actuated control valve. The control valve is subject to the hardest condition, the most expensive item and the most prone to incorrect selection.

There is no glamour in the control valve like there is in distributed control systems. Would any new engineer that graduated from distinguished University be interested in pipe, gasket, flanges, and packing and bothered working with dirt, mud, oilywater when “interfaced” with hardened stainless steel valve trim. It is also hard to hide a 400lb valve under your coat if you make mistake in sizing and selection and the valve needs to be changes.

Fig 1 Debris was found inside the control valve between the plug and seat ring

Fig 2. valve cage

But there are some reason for using valves.  they work and they are great to stand on for you to reach field mounted transmitter reached. If you are still interested, the following subject may be important for choosing the right control valve.

Control Valve Operation and Design Criteria for Beginners 2

Today, control valve can be sized easily by using software in a PC, but in the reality 83.43% of the control valve are sized incorrectly. 76.1 % are too big, 5.13% are too small, 2.2% are both (hahaha). The reason is lack of understanding about vapour pressure (which makes valve cavitate and flash), fluid property (if the service is slurry, the slurry can block the trim and everybody thinks that the valve is undersize) ,and all the things that are mentioned in the flow chart

If the valve is sized incorrectly and the valve needs to be changed, everybody will know it. And it is hard to change it insitu, not including how to perform the seat leak test when the valve had been changed.

Orifice (Differential Pressure) Flow meter Design 1

For Flow meters selection and sizing, use the orifice flow meter. You will waste some energy and money but at least you can relate to its principle of measurement. It is also requires a basic philosophy and prejudice. The most popular method of the flowmeter selection is to use an orifice unless it won’t work.

Reason for using orifice (DP flow transmitter)
Simple (but they are hard to install to get a good velocity profile)
Inexpensive (well there are cheap ultrasonic flowmeters with better accuracy and turndown ratio than DP transmitter today)
Available in various sizes, type, and connections.
Simple design, rugged, and suitable for liquids, gases, steam.

Why am I writing a technical blog

Why am I writing a technical blog? I’m not trying to win a literary awards or become rich and famous ( Maybe I am trying to impress my friends, relatives and associates a little bit). For me the most important thing is a sense of accomplishment to share what I have learned and insure it is not lost.

How do I get the idea out?

Two Phases Oil And Gas Separation Level Measurement

Produced wellhead fluids are complexes mixture of hydrocarbon liquid and gas with different physical characteristics such as density, vapor pressure, .. etc.

Therefore the physical separation between three phases ( water, oil, and gas) is one of the basic production, processing, and treatment in oil and gas facilities.

Separator where mainly designed for mechanically separate liquid hydrocarbon and gases at specific temperature and pressure.

Proper design for separator ( including the instrumentation) is important because separation vessel is normally the initial processing vessel at any facilities.

Oh you’re an Instrument Engineer, The chosen Few (hahaha)

No one plans to become an instrument engineer.The prospective instrument engineer doesn’t even know the profession exists until the job offer comes. Public understanding to the profession is nonexistent.

Do you got What it takes to become an instrument engineer? Do you like to read hundreds pages of catalogs? Do you like to keep track with thousands of instrumentation that changes yearly? Are you capable of forgetting all the math you learned in college?

Being an Instrument engineer is like being paid to go shopping to your nearest electronics or computer store with someone else money.


What is unfortune is that the experienced engineers typically don’t like to speak in public or write. The result is a shortage of good mentors and instructors.

Orifice (Differential Pressure) Flow meter Design 2

Orifice plates are really hard to install. To get a good velocity profile, the mechanical specification for meter tube, the orifice flanges or fitting the differential pressure sensing taps, the upstream and downstream piping requirements must be adhere to the standard. But don’t worry, velocity profiles are only pretty pictures in engineering textbooks

Orifice Plates and holders

Orifice plates are usually installed between special flanges in a horizontal pipe run. The flanges are thicker than normal to accommodate two small bore tapings for connection to a DP cell. The plate is positioned concentrically within the flange bolt circle with the tap protruding near the top of flanges. The tab has a hole and the orifice plates must have information engraved to indicate the correct upstream / downstream orientation.

Control Valve Operation and Design Criteria for Beginners 1

Control valves are used throughout the process to control pressure, level, temperature, or flow. All control valves have variable opening or orifice. For a given pressure drop across the valve, the larger the orifice the greater the flow through the valve.

















Fig 1: Typical single-port body control valve (courtesy of Fisher)