Following the table of material selection for o-ring and seal.
|
Material |
Max Temp. |
Min Temp. |
Recommended for use in |
Not recommended for use in |
| Viton® GFLT | +400° F (+200° C) |
-40° F (-40° C) |
General purpose, steam, ethylene | Ketones (MEK, acetone), skydrol fluids, amines, anhydrous ammonia, low molecular weight esters and ethers, hot hydrofluoric or chlorosulfuric acids, sour HCs |
| EPDM | +250° F (+120° C) |
-60° F (-50° C) |
Acetone, MEK, skydrol fluids | Petroleum oils, di-ester base lubricants, propane, steam, anhydrous ammonia |
| Kalrez® (4079) |
+400° F (+200° C) |
-40° F (-40° C) |
Inorganic and organic acids (including HF and nitric) aldehydes, ethylene, glycols, organic oils, silicone oils, vinegar, sour HCs | Black liquor, hot water/steam, hot aliphatic amines, ethylene oxide, propylene, oxide, molten sodium, molten potassium, anhydrous ammonia |
| Aegis PF128 | +400° F +(200° C) |
-4° F (-20° C) |
Inorganic and organic acids (including HF and nitric) aldehydes, ethylene, glycols, organic oils, silicone oils, vinegar, sour HCs , steam, amines, ethylene oxide, propylene oxide | Black liquor, Freon 43, Freon 75, Galden, KEL-F liquid, molten sodium, molten potassium, anhydrous ammonia |
| Borosilicate | +850° F (+431° C) |
-320° F (-196° C) |
General high temperature/high pressure applications, hydrocarbons, full vacuum (hermetic), ammonia, chlorine | Steam, hot alkaline solutions HF acid,media with ph>12 |
Source: Magnetrol
There are properties of level transmitter displacer type to define the transmitter orientation. It’s useful when we design the configuration of level in limited space.
The default is left hand position number 1. The number show the position which is industry practical standard.
Left hand mounting
Right hand mounting
Source: GE Energy
Here, we will discuss about basic control valve globe type which used widely in process industry. Further we will discuss about other type, materials, packing, actuator, accessories etc.
I list that 3 properties to be highlighted during early selection before sizing. That are:
- Body
- Plug
- Trim Cage
In major application, type of body:
- Two port, straight or angle
- Three port
Type of plug:
- Balance
- Unbalance
There 3 main trim cage type of globe valves:
- Quick Opening,
- Linear,
- Equal Percentage.
About body, it’s easy to select the type based on the purpose. About plug type, make it easy to consider balance or unbalance. For unbalanced plugs are solid and are used with smaller valves or with low pressure drops across the valve.
Advance about plug, note that advantages of unbalance are simpler design, with one possible leak path at the seat and usually lower cost. The disadvantages are the limited size; with a large unbalanced plug the forces needed to seat and hold the flow often becomes impractical.
Balanced plugs have holes through the plug. Advantages include easier shut off as the plug does not have to overcome static forces. However, a second leak path is created between the plug and the cage, and cost is generally higher.
About trim cage type, first we must to consider the characteristic of inherent flow. Inherent flow characteristic is defined as relationship between the flow rate and the closure member travel as it is moved from the closed position to rated travel with constant pressure.
Fisher defined the commonly specified inherent flow characteristics include:
Linear Flow Characteristic
A valve with an ideal linear inherent flow characteristic produces flow rate directly proportional to the amount of valve plug travel, throughout the travel range. For instance, at 50% of rated travel, flow rate is 50% of maximum flow; at 80% of rated travel, flow rate is 80% of maximum; etc. Change of flow rate is constant with respect to valve plug travel. Valves with a linear characteristic are often specified for liquid level control and for flow control applications requiring constant gain.
Equal-Percentage Flow Characteristic—
Ideally, for equal increments of valve plug travel, the change in flow rate regarding travel may be expressed as a constant percent of the flow rate at the time of the change.
The change in flow rate observed regarding travel will be relatively small when the valve plug is near its seat and relatively high when the valve plug is nearly wide open. Therefore, a valve with an inherent equal-percentage flow characteristic provides precise throttling control through the lower portion of the travel range and rapidly increasing capacity as the valve plug nears the wide-open position.
Valves with equal-percentage flow characteristics are used on pressure control applications, on applications where a large percentage of the pressure drop is normally absorbed by the system itself with only a relatively small percentage available at the control valve and on applications where highly varying pressure drop conditions can be expected. In most physical systems, the inlet pressure decreases as the rate of flow increases, and an equal percentage characteristic is appropriate. For this reason, equal percentage is the most common valve characteristic.
Quick-Opening Flow Characteristic—
A valve with a quick opening flow characteristic provides a maximum change in flow rate at low travels. The curve is basically linear through the first 40 percent of valve plug travel, then flattens out noticeably to indicate little increase in flow rate as travel approaches the wide-open position. Control valves with quick-opening flow characteristics are often used for on/ off applications where significant flow rate must be established quickly as the valve begins to open. Consequently, they are often used in relief valve applications. Quick-opening valves can also be selected for many of the same applications for which linear flow characteristics are recommended, because the quick-opening characteristic is linear up to about 70 percent of maximum flow rate. Linearity decreases sharply after flow area generated by valve plug travel equals the flow area of the port.
Source : Fisher
#1 Express Gratitude
- When you appreciate what you have, what you have appreciates in value
- If we aren’t thankful for what we already have, we will have a hard time ever being happy
#2 Cultivate optimism
- People who think optimistically see the world as a place packed with endless opportunities, especially in trying times.
#3 Avoid over-thinking and social comparison
- Comparing yourself to someone else can be poisonous
- The only person you should compare to is yourself before now
#4 Practice acts of kindness
- Selflessly helping someone is a super powerful way to feel good inside
#5 Nurture social relationship
- The happiest people on the planet are the ones who have deep, meaningful relationships
#6 Develop strategies for coping
- It helps to have healthy strategies for coping pre-rehearsed, on-call, and in your arsenal at your disposal
#7 Learn to forgive
-
Harboring feelings of hatred is horrible for your well-being
#8 Increase flow experiences
- Flow is a state in which if feels like time stand still
- It’s when you’re so focused on what you’re doing that you become one with the task
- Nothing is distracting you or competing for your focus
#9 Savor life’s joys
- Deep happiness cannot exist without slowing down to enjoy the joy
#10 Commit to your goals
- Magical thins start happening when we commit ourselves to doing whatever it takes to get somewhere
#11 Practice spirituality
- When we practice spirituality or religion, we recognize that life is bigger than us
- We surrender the silly idea that we are the mightiest thing ever
#12 Take care of your body
- Taking care of your body is crucial to being the happiest person you can be
—
“Good communication should not be saved for special occasions, but should be a part of our everyday life”
“STRENGTH – a river cuts through a rock not because of its power, but its persistence”
“There are plenty of difficult obstacles in your path, don’t allow yourself to become one of them” – Ralph Marston
“The past is like using your rear-view mirror in the car, it’s good to glance back and see how far you’ve come, but if you stare too long you’ll miss what’s right in front of you”
“If you do things the way you’re always done them, you can’t expect to get better results than you did before”
“In your planning you need to leave room for the unexpected, so that even if a problem comes up you can still get the results you want”
“Those who try to do something and fail… are infinitely better than those who try to do nothing and succeed….”
Three simple rules:
- If you don’t go after what you want, you’ll never have it.
- If you don’t ask, the answer will always be no.
- If you don’t step forward, you will always be in the same spot.
So go for what you want, ask questions, and take that one step forward because you never know where it might lead….
“The size of your success is measured by the strength of your desire; the size of your dream; and how you handle disappointment along the way”
“Change is an attitude of mind and the place to start is within ourselves”
“One of the most common causes of failure is the habit of quitting when one is overtaken by temporary defeat” – Napoleon Hill
“Life is always full of surprises and great adventures.. you just got to get out from your comfort zone, go forward and enjoy life as you move on”
“Life and success is a journey and you continue to grow with every step. The only way to lose is if you stop the journey and go off the path”
It’s called from IEC/EN 60079-10-2, classification of areas – Combustible dust atmosphere. It’s differ with gas zone classification since applies 2 digit to identify the classification.
Following the zone classification for dust:
Zone 20 : Area in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously or for long periods or frequently
Zone 21: Area in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur, occasionally, in normal operation
Zone 22: Area in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation, but if it does occur, will persist for a short period only.
The bodies which can issue certificate for electrical equipment compliances with related standard for use in potentially explosives atmospheres are called as mention in the title.
There are three types of certificates for equipment:
- Certificate of conformity
- Certificate for component
-
Certificate of Ex electrical apparatus
Following the NRTLs of various countries. Note that most of NRTLs have reciprocal agreement which allow other labs outside of their country to test and certify equipment to the countries standards.
| No |
Country |
Test Authority |
| 1 | Australia | SAA |
| 2 | Brazil | CEPEL |
| 3 | Canada | CSA |
| 4 | Denmark | DEMKO |
| 5 | France | LCIE, CERCHAR |
| 6 | Germany | PTB, DMT, TUV |
| 7 | Holland | KEMA |
| 8 | Italy | CESI |
| 9 | Japan | JIS |
| 10 | Norway | NEMKO |
| 11 | Spain | LOM |
| 12 | South Africa | SABS |
| 13 | Sweden | SEMKO |
| 14 | UK | BASEEFA2000, SIRA, EECS |
| 15 | USA | UL, FM, ETL |
Source: Cooper Crouse-Hinds Ex Digest Testing and Approvals
The IP is followed by two numbers. First number provided the degree of protection against solid objects and dust. Second number is degree of protection against water. This called from IEC 60529.
FIRST NUMERAL – against solid particles
| 0 | No Protection |
| 1 | Objects equal to or greater than 50 mm |
| 2 | Objects equal to or greater than 12.5 mm |
| 3 | Objects equal to or greater than 2.5 mm |
| 4 | Objects equal to or greater than 1.0 mm |
| 5 | Dust Protected |
| 6 | Dust Tight |
FIRST NUMERAL – against liquid
| 0 | No Protection |
| 1 | Vertically dripping water |
| 2 | 750 to 1050 angled dripping water |
| 3 | Spraying water |
| 4 | Splashing water |
| 5 | Water jets |
| 6 | Heavy seas, powerful water jets |
| 7 | Effects of immersion |
| 8 | Indefinite immersion |
NEMA (North American Electrical Manufacturers Association) also issue about protection against solid particles and liquid. There is equivalent table in associates IP rating while there may be differences in the detail of testing code such as nozzle size or water velocities.
Below is conversion of NEMA type number to IP rating
| NEMA type number | IP Rating |
| 1 | IP10 |
| 2 | IP11 |
| 3 | IP54 |
| 3R | IP14 |
| 3S | IP54 |
| 4 and 4X | IP56 |
| 5 | IP52 |
| 6 and 60 | IP67 |
| 12 and 12K | IP52 |
| 13 | IP54 |
ASME Code stamps are listed in the associated sections of the ASME Boiler and Pressure Vessel Code. Following the associated sections:
Section I : A, E, M, PP, S, V
Section II : none
Section III : N, NA, NPT, NV
Section IV : H, HLW, HV
Section V : None
Section VI : None
Section VII : None
Section VII : Division 1: U, UM, UV
Division 2: U2, UV
Division 3: U3, UV3
Section IX : None
Section X : RP
Section XI, XII, B31.1, PTC 25-1994 : None
It’s about the test code. The main code as follow:
- Flame Retardant : IEC-60322
- Fire Resistant : IEC-60331
That’s all. But of course we have to learn more than that. The title of IEC-60331 is Test for Electric Cables under Fire Conditions – Circuit Integrity. For IEC-60322 is Test on electric cable under fire conditions. In detail the IEC-60331 is subdivided in several parts:
IEC-60331-1 : Part 1 – Test method for fire with shock at a temperature of at least 803oC for cables of rated voltage up to and including 0.6 / 1.0 kV and with an overall diameter exceeding 20m
IEC-60331-1 : Part 2 – Test method for fire with shock at a temperature of at least 803oC for cables of rated voltage up to and including 0.6 / 1.0 kV and with an overall diameter not exceeding 20m
IEC-60331-1 : Part 3 – Test method for fire with shock at a temperature of at least 803oC for cables of rated voltage up to and including 0.6 / 1.0 kV tested in a metal enclosure.
IEC 60331-11: Part 11: Apparatus – Fire alone at a flame temperature of at least 750 °C
IEC 60331-21: – Part 21: Procedures and requirements – Cables of rated voltage up to and including 0,6/1,0 kV
IEC 60331-23: – Part 23: Procedures and requirements – Electric data cables
IEC 60331-25: – Part 25: Procedures and requirements – Optical fibre cables
For IEC-60322, as follow:
IEC 60332-1: Test on electric cables under fire conditions. Test on a single vertical insulated wire or cable
IEC 60332-2: Test on electric cables under fire conditions. Test on a single small vertical insulated copper wire or cable
IEC 60332-3: Test on electric cables under fire conditions. Test on bunched wires or cables
Other standard also mentioned about fire resistant, such as BS EN 50200:2006 (equivalent with IEC 60331-2), BS EN 50362:2003 (equivalent with IEC 60331-1), BS 6387:1994, BS 8434-2:2003, BS 8491:2008.
Source: Cavicel.com
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