Hi, reader welcome to a new post in this post we will have a detailed look at Pitot Tube. A Pitot tube is a simple type of flow sensor and is used for different applications like the air speed of racing cars and air fighter speed. It is also part of different industries for measuring air flow of pipes, ducts, and stacks.
Introduction to pitot tube
- The pitot tube is a low-cost meter that is used as a replacement for an orifice plate and it has an accuracy of about 0.5 to five percent that can compared with the orifice.
- The flow range of this meter is about 3:1 which is the same as the orifice plate. Pitot tube based on the Bernoulli equation that defines that the flow of a fluid increases, pressure loss occurs
- the basic difference between a pitot tube and an orifice plate is that an orifice is used for measuring the complete flow stream and a pitot tube is used for measuring the flow rate at one point of flow.
- it is main feature is that can be put in existing and pressured pipelines without stopping fluid flow.
Working of the pitot tube
- The pressure difference meter is called and processes two pressures first one is static and the other is net bearing pressure.
- The static pressure is applied in a tube or atmosphere, upstream to the pitot tube.
- This meter is configured at 90 degrees to flow the path in place of the turmoil position.
- The bearing pressure (PT) is a measurement of static and dynamic pressure and is defined as the curving tributary effect on the pitot opening point.
- The bearing pressure is measured with the use of an L-type tube that is put in the path of fluid flow.
- The point velocity of approach Vp can measured through the square root of a dynamic process is the difference between net pressure and static pressure and product with a C/D ratio,
Vp= C(PT – P)½/D
- If the flow rate is measured by taking the product of point velocity Vp with a cross-sectional area of the pipe. It is good that velocity measuring can done at an insertion depth that is related to the average velocity.
- When flow velocity increases velocity in pipe also varies in laminar ways to trubulant. That varies the point of average velocity and needed setting of insertion depth.
- Pitot tube used for high turbulent flow that has Reynolds numbers > 20,000 and for these conditions, velocity profile causes to flate so insertion depth does not have a high effect
Applications Pitot Tube
- In manufacturing, the flow speeds calculated are frequently those curving in pipes and pipes where calculations by an anemometer would be hard to find.
- In these classes of quantities, the supreme applied tool to use is the pitot tube.
- The pitot tube can be introduced by a slight hovel in the tube with the pitot associated to a U-tube or some other differential pressure gauge for determining the flow speed inner side of the ducted breeze subway.
- One usage of this method is to govern the dimensions of air that is being transported to a trained place.
- The rate of flow of liquid can be calculated by the given formula.
flow rate = pipe area (square feet) × flow speed (feet per minute)
flow rate = pipe area (square meters) × flow speed (meters per second)
- In aeronautics, air velocity is characteristically dignified in knots.
- In weather places with extraordinary wind velocity, the pitot tube is changed to make a special type of of anemometer which is called a pitot tube static anemometer.
Advantages:
- It is a less cost, small meter and there is no need of any moveable part.
- In this meter, there is less lasting pressure damage.
- We can install it very easily.
Disadvantages:
- External solids in a liquid can simply block the pitot tube and disturb the usual interpretation as a consequence.
- Its accuracy is Low.
- Its range capability is less.
FAQS
What are the benefits of using a pitot tube?
- The Pitot tube is small and essay to handle device does not come with any moving components. It is low-cost and comes with low permanent pressure. Pitot tube can connected to the existing system.
How does the pitot work?
- The pitot-static system uses the air pressure gradient rule. it operates by measuring pressures or pressure differences and uses these values for speed and altitude values
What instruments use pitot tube?
- 3 flight instruments use a pitot-static system such as the airspeed indicator, the altimeter, and the vertical speed indicator.
What is a pitot tube used to measure *?
- Pitot tube is devices employed for measuring the velocity of flow for any point of the pipe. The pitot tube is used for measuring velocity at a point
What are the characteristics of a pitot tube?
- Pitot tubes used in aircraft as speed measuring devices and tubes on aircraft are about ten inches longer with 1/2 inch diameters. Some small holes are made in the external design of the tube and the center hole is made down the side of the axis of the tube.
What are the limitations of the pitot tube?
- If there is a low velocity, the pressure difference is small and not easy to measure with the transducer.
- Error in the device can be higher than measured values.
What is the Bernoulli equation for the pitot tube?
- The Bernoulli equation for the pitot tube is P1=P2+(ρV22)/2 here Pi is pressure in stagnation point 1 and P2 is pressure in point 2.
What are the precautions for pitot tube?
- The pitot static tube must be strongly fixed and must connected at 90 degrees. The angle of the jaw must be equal to zero.
- the mini meter and manometer must configure strongly and accurate level.
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So that is a detailed post about the pitot tubes. if you have any further queries ask in the comments. thanks for reading. Have a nice day.
In terms of accuracy for the Pitot tube, what is the lowest acceptable range (differential pressure) capable of providing a proved delta P?
E.g., Unsing the standard Pito tube and the incline manometer, can the combination of both units be able to read differential pressures as low as 0.001 inches of water? (Application; mesuring low velocities inside the stack with ambient air).
Using the same example above with the difference of using a digital manometer, can a reading of 0.0007 inches of water be valid or acceptable? or is it outside of the Pitot tube capabilities and it should be considered a noise?
Thank you.