Pitot tube use instructions

Warranty instructions

Our company is responsible for the warranty period of 12 months for the L-type pitot tube. The warranty period starts from the date the user gets the instrument. When the user is in use, he should follow the instructions for use. Due to improper use of the user or poor working environment, the instrument may not be damaged.

important hint

1. Before using the instrument, read the operation manual carefully.

2. The instrument must be used and maintained by trained personnel.

3. The use of this instrument must be operated according to the rules established by our company.

4. The maintenance of the instrument and the replacement of parts must use original spare parts of our company.

5. If the user does not repair the replacement parts in accordance with the above instructions, the reliability of the instrument

Let the operator take responsibility.

6. The use of this instrument should also comply with the regulations and rules of the relevant domestic departments and instrument management in the factory.

Pitot tube instruction manual

A pitot tube is connected to the instrument as shown below. The Bernoulli equation can be used to calculate the flow velocity V at a certain point in the fluid.

Where: V = K√2P/ρ

V wind speed (m/s)

K Pitot coefficient

P Dynamic pressure measured by pitot tube (Pa )

ρ fluid density (kg/m3)

After measuring the wind speed at multiple points and obtaining the average wind speed, the air volume can be calculated. Q=3600×V×F

In the formula:

Q Airflow (m3/h)

V mean wind speed (m/s)

F Pipe cross-sectional area (m2)

Second, the main technical parameters:

The L-type pitot coefficient is between 0.99-1.01, and the S-type pitot is between 0.81-0.86. The measured air flow rate does not exceed 40m/s, and the measured flow rate does not exceed 25m/s. 3. The Φ8 tube is the longest 1500mm, the Φ10 tube is the longest 2000mm, (the company has various pitot tubes)

Third, the main purpose:

In scientific research, production, teaching, environmental protection, and tunnels, mine ventilation, and energy management departments, Pitot tubes are commonly used to measure the airflow velocity in ventilation ducts, industrial ducts, and kiln flue ducts, and the flow rate can be determined through conversion to measure the water flow in the ducts. speed. The use of Pitot tube to measure the speed and determine the flow rate has a reliable theoretical basis and is easy to use and accurate. It is a classic and extensive measurement method. In addition, it can also be used to measure the pressure of a fluid.

Fourth, the structure: L-type Pitot tube with two different straight through the stainless steel tube concentric socket, the inner tube through the straight end of the joint is a full pressure tube, the outer tube through the side of the joint is a static pressure tube. The pointing rod is in the same direction as the head of the rod. When used, the direction can be determined so that the probe is aligned with the flow direction. The S-type pitot tube is made from two branches facing away from each other. The windward side is the full-pressure side and the lee side is the static side.

V. How to use:

It is necessary to select the cross section of the measuring point correctly to ensure that the measuring point smoothly flows through the straight pipe section. For this reason, the local components such as elbows, valves, and variable diameter tubes in the direction of the flow direction of the measured cross-section must be greater than 4 times the pipe diameter. The local elbow and reducing structure in the downstream direction should be greater than 2 times the pipe diameter. The diameter of the pitot tube is selected in accordance with the diameter ratio of the pipe under test and is not greater than 0.02. In order to avoid interference, increase the error. Do not allow the Pitot tube to be close to the wall when measuring. When measuring, the full pressure hole should be aligned with the direction of the air flow to point to the rod. The measurement point should be inserted into the hole to avoid air leakage and prevent air flow interference on the section. According to the technical specifications for pipeline surveying, the survey point of the survey section should be reasonably selected.

The Pitot tube can only measure the flow velocity at a certain point on the pipeline section, but the average flow velocity is used to calculate the flow rate. Because the flow distribution of the cross-section is not uniform, several points should be measured on the section to obtain the average value.

Measurement points are measured by the flue (pipeline) measurement method, and are classified according to the “log-linear” method, and can also be divided according to the commonly used equally divided areas.

5. S-type pitot tube static pressure joints are marked with a marking number, and the pitot coefficient is indicated on the identification sheet. The identification sheet should be kept for a long time for calculation.

Six, maintenance

May cause the tube to bend during use. Check once before use, noticeable deflection is pre-aligned, and cone-head damage can no longer be used.

2. After use in dusty pipes, there may be dust or moisture in the pipes. Should be blown after use, after the box is blown. Or test the smoothness before use. Clean the inner and outer tubes timely after use to ensure long-term good condition.

3. Small static pressure holes often check, do not make impurities plug the small holes, causing pressure barriers.

4. The standard pitot inspection cycle is five years.

VII. Execution standards: The national measurement standard number JJG518-94.

Beijing 01100013

Measuring instrument name L type pitot tube

Measurement coefficient 0.998

Model size L type

Factory number L

Unit Beijing Xia Ya Electronics Co., Ltd.

According to the result of the test, the measuring instrument is allowed to be used for level 1.0

Inspector

inspector

Verification date: 2013

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