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Fail-safe position

Fail-Safe Position Selection of Control Valve

In designing a processing facility, we usually use control valve to manipulates the temperature, pressure, level, or fluid flow rate in process system. The selection of control valve, which is air-to-open or air-to-close, is base on safety consideration. In case of power loss or air failure , control valve should move in safe position (fail-safe).

Fail Position

Fail position is the term used to describe how control valve will react when there is loss of power. I read there are three different fail positions. Read More

Storage Tank Selection

In my recent project, there are at least eight liquid storage tanks we need to design and purchase. Although, the design of storage tank is not part of my work (it is a job of mechanical engineers), but I always wonder how people design the tanks. In this post, I want to share to you the results of my desktop study about liquid storage tank selection. Read More

IP Codes

The IP CodesIngress Protection Rating, sometimes also interpreted as International Protection Rating, classifies and rates the degree of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in mechanical casings and with electrical enclosures.

A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.

The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.

Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:

  •  The first digit represents protection against ingress of solid objects.
  •  The second digit represents protection against ingress of liquids.

The larger the value of each digit, the greater the protection. As an example, a product rated IP54 would be better protected against environmental factors than another similar product rated as IP42.

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References:

  1. IP ratings. http://www.mpl.ch/info/IPratings.html
  2. IP code. http://en.wikipedia.org/wiki/IP_Code

Plant Layout Consideration

About a week ago my boss asked me something crucial about Plant Conceptual Design and Layout for our bankable feasibility study of ferronickel project. He asked me if I had explained why we chose this part as smelter plant and not on that part, why the gate should be on the west side of the processing plant, and so on. I just shook my head and grinning. BIG NO! 

My boss was emphasizing the philosophy to make site plan. There are several considerations to make site plan. For example, the processing facilities which are heavy, require high load, and very dynamic, should be positioned at the relatively flat and so on.

I started to think what aspects we need to consider making plant layout. Read More