DP Transmitter

Information about
Differential Pressure
Pressure Transmitter
Definition
Industrial dp transmitter
Construction
Internal arrangement
Uses
Advantage and disadvantage
covered all the concepts

1. MALAVIYA NATIONAL INSTITUTE OF TECHNOLOGY JAIPUR DEPARTMENT :- CHEMICAL ENGINEERING BY :- Krishna Kant Nayak MNIT, Jaipur 2016uch1239

2. DIFFERENTIAL PRESSURE TRANSMITTER CONTENTS :- Differential Pressure Pressure Transmitter Definition Industrial dp transmitter Construction Internal arrangement Uses Advantage and disadvantage

3. DIFFERENTIAL PRESSURE The difference in magnitude between some pressure value and some reference pressure . In a sense , absolute pressure could be considered as a differential pressure with total vacuum or zero absolute as the reference .Likewise , gauge pressure could be considered as Differential Pressure with atmospheric pressure as reference.

4. PRESSURE TRANSMITTER A Pressure Transmitter is used where indication and/or record of pressure is required at a location not adjacent to the primary element. A Pressure Transmitter is used for both indication and control of a process. A Pressure Transmitter is used where overall high performance is mandatory. These can be either Gauge , Absolute or Differential Pressure Transmitters.

5. DEFINITION Differential pressure transmitter is a equipment which sense the difference in pressure between two ports and produce an output signal with reference to a calibrated pressure range.

6. INDUSTRIAL DP TRANSMITTER The industrial differential pressure transmitters are made of two housings. Pressure sensing element is housed in the bottom half, and the electronics are housed at the top half. It will have two pressure ports marked as “High” and “Low”. 

7. DIFFERENTIAL PRESSURE TRANSMITTER CONSTRUCTION A .  Direct Pressure sensing element (located in the lower housing):-  This diaphragm is a mechanical device.  It is placed in between the two pressure inlet ports. The diaphragm will be deflected by the applied pressure.

8. B .   Electronic Unit :- The electrical signal generated at the lower chamber by the sensor is in the range of milli-volt only. This part is housed on the upper part of transmitter. C .  2-Wire 4-20mA Current Transmitter:- A DC output current is generated which is directly proportional to the pressure range of the Differential Pressure Transmitter.  

9. INTERNAL ARRANGEMENT OF BOTTOM &TOP HALF OF DP TRANSMITTER

10. USES OF DP TRANSMITTER SOME USES OF DP TRANSMITTERS:- Measuring positive gauge pressure Measuring absolute pressure Measuring vacuum Measuring liquid level Measuring gas and liquid flow

11. DP TRANSMITTER ADVANTAGE DISADVANTAGE Easy to install/remove. Offer very little pressure drop of which 60% to 65% is recovered. Meter can be easily maintained. Measures a wide range of flow rates. They have a simple construction. They have easily fitted between flanges. They are most suitable for most gases and liquids. They are inexpensive. Requires homogeneous fluid. Requires single phase liquid. Requires axial velocity vector flow. Causes a pressure drop in fluid. Fluid viscosity limits measuring range. Requires straight pipe runs to ensure accuracy is maintained. Pipe line must be fully especially for liquid flow measurement. They have low range-abil ity.

12. REFERENCES Wikipedia NPTEL Website