Answer / carl_ellis

A closed pressure vessel requires a differential pressure
measurement in order to compensate for the pressure or
vacuum in the vapor space above the liquid.

The density is said to be 1, so we'll assume that what was
really meant is that the specific gravity is 1.00, the same
as the specific gravity of water. The measurement can be
made in engineering units of mm of water column (wc) with no
compensation for a specific gravity other than water.

A DP transmitter measurement:
(high side pressure) minus (low side pressure)

The low side pressure reading is (vacuum pressure).
The high side pressure reading is (column of water pressure
+ vacuum pressure)

(water column pressure + vacuum pressure) minus vacuum
pressure = water column pressure.

With a vertical elevation difference between the flanges of
440mm, the water column pressure will be
0 - 440mm wc.
LRV = 0.0 mm wc
URV = 440 mm wc

Carl Ellis
Measure First

in i/o panel for digital ouput(do) how much power(in volts) we must give?

2 Answers  

---

What is the use of temprature compensation?

0 Answers  

---

how u meassure a room temp?in rtd or themo couple?

4 Answers  

---

The performance of a pump is monitored by measuring the ________ and _________ pressures

1 Answers  

---

how to convert transmitter milliamps output to like temp,pressure etc.....

5 Answers  

---

Can DP transmitter with orifice plate works on Beta ratio 0f 0.3 and differential pressure of 100 MMWC in liquid service application?

1 Answers  

---

1.what is beta in control valves? 2.what is the condition followed by light in LASERs? 3.1kg/cm2=?psi 4.Integral action reduces what? 5.about vena contracta 6.a simple RC circuit 7.thermistor material's temp coefficient of resistance 8.if wave passes through the thicker area of a chord to a thinner area what changes will occur to wavelength? 9.if 4-20 mA represents 0-10 kg/cm2 what will be the current when pressure is 5 kg/cm2.................

0 Answers   Lurgi,

---

In case of Transmitter's(e.g.Ultrasonic Flow meter ) we have an normal practise of selction of upstream and downstream distance such as (20D and 5D ).can anyone please let me know whow to calculate "D" ?? i guess it refers to pipe thickness is t right ?

2 Answers  

---

what is the dp across a orifice plate & how much is permanent pressure across an orifice plate.

2 Answers   HPCL,

---

hi i'm an Instrumentation student,i have one doubt that we can call- > computer science as CS > Information science as IS > Electronics & communication as E & C In the same way what is short term for Instrumentation....?

11 Answers  

---

principle of dead weight tester ?

0 Answers  

---

How many ohms are required for proper earthing?

0 Answers  

---