Product Description
Pitot tube flow meter
I. Main Characteristics of Pitot Tube Flowmeters
A Pitot tube, also known as a Pitot-static tube, is a tubular
device used to measure the total pressure and static pressure of a
gas to determine its flow velocity. It was originally invented by
the Frenchman H. Pitot, hence its name. Initially, it was primarily
used for measuring aircraft speed. Based on this principle, Hongqi
Company designed the HQ-PTG series Pitot tube flowmeter, a
measuring device that calculates the gas flow rate by measuring the
pressure at the sampling point, applying Bernoulli's principle to
determine the gas velocity, and then multiplying it by the
cross-sectional area.
Pitot tube flowmeters are suitable for measuring the flow velocity
of various media such as steam, liquids, air, and gases, and are
particularly well-suited for measuring airflow velocity in
large-diameter ducts. They determine flow rate by measuring the
airflow velocity in pipes and flues of furnaces and kilns, and then
performing calculations. Widely used in scientific research,
production, teaching, environmental protection, cleanrooms, mine
ventilation, and energy management departments, they feature
reliable principles, simple structure, and low cost, making them an
ideal flow measurement instrument for online monitoring systems of
industrial boiler gas emissions.
II. Components of a Pitot Tube Flowmeter
The HQ-PTG series Pitot tube flowmeter generally consists of a
primary flow restriction element (sensor), a transmitter, and a
valve assembly. In special cases, it may also include a ball valve,
an in-line insertion/removal device, and a purge valve.
III. Working Principle of Pitot Tube Flowmeter
The Pitot tube flowmeter consists of a small metal tube with a
double-layered structure bent at a right angle. It has a total
pressure port facing the flow at the top and static pressure ports
around the side wall. The sensor is inserted into the center of the
pipe, with the total pressure port aligned with the upstream flow.
The difference between the total pressure and the static pressure
is the measured differential pressure at the center of the pipe.
The differential pressure transmitter is connected to the total
pressure tube and the static pressure tube. Based on the
mathematical model and measured data, a curve is fitted to
determine the corresponding flow rate. The corresponding flow rate
signal is then converted into a standard 4-20mA signal by the
differential pressure transmitter.
IV. Main Characteristics of Pitot Tube Flowmeters
1. Capable of measuring various media
Suitable for measuring the flow velocity of various media such as
steam, liquids, air, and gas, especially ideal for measuring wind
speed in large-diameter air ducts. It features reliable principles,
simple structure, and low cost, making it an ideal flow measurement
instrument for industrial boiler flue gas emission online
monitoring systems.
2. Optional online installation, removal, cleaning, and
backflushing devices
For measuring points where production cannot be stopped for
installation, an online insertion and removal device can be used
for installation without interrupting production. For media
containing excessive impurities or dirt, to prevent clogging of the
pressure tap, an online insertion and removal device can be used
for regular cleaning, or an online backflushing device can be used
for backflushing to ensure long-term accurate and reliable
measurement.
3. Central Pressure Measurement, Inherently Clog-Resistant
The sensor is located at the center of the pipeline for pressure
measurement, making it inherently clog-resistant. An optional
configuration with a cleaning rod allows for online automatic
cleaning, further improving clog prevention.
4. Low Installation Costs, Virtually Maintenance-Free
The insert-type installation is simple, and the unique
wear-resistant coating on the sensor tip ensures the sensor's shape
remains unchanged over time, resulting in excellent long-term
stability.
VI. Selection Table for Pitot Tube Flowmeters
Pitot Tube Flowmeter Selection Code Table
| HQ-PTG | Pitot tube flowmeter |
| Nominal diameter | □ | DN20-2000 |
| Connection method | -F | Flange |
| -J | Square Flange |
| -E | Other Connection |
| -N | Economical flanged ball valve with online plug-in design. |
| -W | Economical flanged ball valve with leak-free online insertion and
removal capability. |
| Structure | T | Integrated |
| X | split type |
| Sensor material | Q | SS304 |
| L | SS321 |
| A | SS316 |
| B | 15CrMoG |
| E | 1Cr5Mo |
| F | 16Mn |
| H | HC276 |
| P | PTFE |
| M | Monel |
| T | Wear-resistant alloy steel |
| W | SS316+Tungsten carbide coating |
| Z | SS316+Ceramic coating |
| S | Other materials |
| Flange Standard | 0 | Not applicable (for direct soldering type selection) |
| 1 | HQ20592-2009 |
| 2 | HG20615-2009 |
| 3 | GB/T9115-2010 |
| 4 | JB/T81-94 |
| 5 | ANSI B 16.5 |
| 6 | Rectangular flange |
| 7 | Other types |
| Sensor Number | 1 | Sensor 1 (DN200~DN500) |
| 2 | Sensor 2(DN400~DN1000) |
| 3 | Sensor 3(≥DN1000) |
| Level Class | A | 0.25MPa |
| B | 0.6MPa |
| C | 1.0MPa |
| D | 1.6MPa |
| E | 2.5MPa |
| F | 4.0MPa |
| G | Customized |
| Pipe Material | C | Carbon steel |
| L | SS321 |
| Q | SS304 |
| A | SS316 |
| E | 15CrMo |
| S | Other Material |
| Pressure tap type | 1 | Threaded connection, with openings on both sides. |
| 2 | Socket welding, opening facing upwards. |
| 3 | Threaded connection, opening facing upwards. |
| 4 | Connecting joint, opening upwards. |
| 5 | Direct standard type (three-valve manifold for process connection) |
| Attachments | VCPS | Anti-blocking |
| VCPL | Test tube type |
| A | Three-valve manifold |
| B | Needle valve |
| C | Condensation tank (for high-temperature media) |
| G | Gate |
| L | Cleaning rod |
| N | Globe valve |
| R | Backflushing device |
| T | Others |
*When the Pitot tube flowmeter is of the split type, it does not
include all mounting accessories. These are supplied according to
the user's requirements at the time of ordering. The material of
the threaded mounting base and flange mounting base will be the
same as the material of the on-site pipeline.
*When the pipeline is rectangular, the nominal diameter
specification is selected according to the wider dimension.
VII. Pitot Tube Flowmeter Installation Requirements
VII. On-site installation diagram of the Pitot tube flow meter
Certificate Approved
