Answer / carl_ellis

A draft range measurement is typically a gauge pressure
measurement, referenced to atmosphere.

Draft range is very, very low pressure, so DP transmitters
are typically used because they're readily available in
a 'draft' range with the large diaphragms necessary for low
pressure measurements.

The high side is connected to the process with an impulse
tube. The low side is exposed to atmospheric pressure.
Good practice puts a filter, like a scintered pneumatics
filter on the low side, so that dirt doesn't fill the low
side cavity and air movement (wind, passing vehicles) is
buffered and damped to prevent the forces of air movement
on the low side from affecting the draft measurement.

If the impulse line were connected to the low side, the DP
would be negative, a DP subtracts the low side pressure
from the high side pressure (atmosphere minus some positive
pressure = negative pressure). Convention says that draft
range is positive so the impulse connection is to the high
side, to get a positive value.

Tell 'em Carl sent you.

Answer / deepak

Dear Carl,

Cant we use an Absolute pressure transmitter ?

give me the formula for analog to digital converter and also d to a converter

0 Answers   ACC,

---

can i get model question papers of mahagenco exam?

11 Answers   MahaGenco, MSGEN,

---

What is two wire system and how it work

2 Answers   Bhel, IFFCO,

---

In most instances, Inertia processes are quite uncommon. Give an example of a combined Resistance and Capacitance situation.Describe an application, which according to your understanding of the subject matter, comprises of both Resistance and Capacitance effects.

0 Answers  

---

How oil line flow measured?eplain about instruments used and working principle?

0 Answers  

---

---

what is the control valve?how many types of control valves are there

6 Answers   Chemin, Hindustan Zinc,

---

What is three element drum level control system why its better than single element?

0 Answers  

---

how far the two wire transmission (loop power) maximum distance suitable?

2 Answers   PCIL,

---

how can i check vortex shedder bar it is ok? if there is ohms condition are shown correct?

0 Answers   Chevron Phillips,

---

why direct mounted pressure transmitters is always installed with DBB ( double bleed block) valve in process line or top of the tanks ?

0 Answers  

---

WHAT IS THE DIFFERENCE BETWEEN DCS & PLC.

9 Answers   Reliance,

---

why we require Differential pressure?Why we use Orifice Plate?

3 Answers  

---