Answer / aftab ahmed mazari

These are flow paterns.
a. Equal percntage
b. Linear
c. Quick opening

The plug and cage is made in such a way that you can get
flow any one of above construction.
Suppose, Valve cage, plugs are Equal percentage, then at
opening of valve of 30 percent, you may get flow of only 6
to 8%
If linear, then flow also 30%,
If quick opening, then flow almost double, about 60%,
It all depends upon process requirements.
Suppose for vent valve, usually quick opening type valves
are used

aftabmazari@yahoo.com

Answer / imran

•Linear - flow capacity increases linearly with valve
travel.
•Equal percentage - flow capacity increases exponentially
with valve trim travel. Equal increments of valve travel
produce equal percentage changes in the existing Cv.
•A modified parabolic characteristic is approximately
midway between linear and equal-percentage characteristics.
It provides fine throttling at low flow capacity and
approximately linear characteristics at higher flow
capacity.
•Quick opening provides large changes in flow for very
small changes in lift. It usually has too high a valve gain
for use in modulating control. So it is limited to on-off
service, such as sequential operation in either batch or
semi-continuous processes.
•Hyperbolic
•Square Root

Will Intergraph support SmartPlant Instrumentation in an AutoCAD or MicroStation environment on a long-term basis?

1 Answers   Siemens,

---

Draw a complete P&ID of a flow suction tank indicating all control & protection equipment. Indicate all its inlets and outlets. Explain the controls for this system

0 Answers  

---

What are advantages and disadvantage of the ac supply load cell?

0 Answers  

---

I want to know the questions asked in ONGC interview(after being selected in the written exam) for Instrumentation branch.Kindly help.

0 Answers  

---

How many mode are in ups?

2 Answers  

---

---

what is the difference between auto tuning and manual tuning of controllers(eg:PID,PI,PD CONTROLLERS )

2 Answers   GATE,

---

what are the standards used for earthing instruments in the field?

1 Answers  

---

how we can check level probe and controller

2 Answers  

---

What is the relationship between GAIN and PROPORTIONAL BAND.

1 Answers   Kharafi National, Sabic,

---

How can i test procedure grounding for CAT-7 cable? Or How can we test procedure CAT-7 Cable Electrically safe?

0 Answers   Tecnimont,

---

What is the purpose of RS Networks

2 Answers  

---

what is commisioning procedure,2)what is is the main work in commisioning in the field tx to dcs, plz send me detail

0 Answers  

---