Barometer is a kind of instrument used to measure air pressure. There are many classifications, among whichTire pressure gaugeIt is a kind of pneumatic tire pressure gauge, which is composed of a gauge head, a piston, a gauge body, a ruler, a main spring, etc. There is only one air pressure on the gauge headMetering portThe utility model has the advantages of simple structure, small measuring range, high precision and convenient use, and is suitable for the tire pressure measurement of small vehicles such as mini cars, motorcycles, etc.
Tire pressure gauge(tyre pressure gauge) is a kind of pneumatic tire pressure gauge, which is composed of a gauge head, a piston, a gauge body, a ruler, a main spring, etc. There is only one pressure metering port on the gauge head, and the length of the main spring is 60-90mmMedian diameterΦ7－12mm、Pitch2.7 － 3.0mm, steel wire diameter Φ 0.6 － 1.5mm, air pressureMetering portThe included angle between the center line and the axis of the meter body is 90 ° - 180 °, the scale is a square body, and the scale value of the measuring range is 0.07Wpa - 0.4Wpa.The utility model has the advantages of simple structure, small measuring range, high precision, convenient use, and is suitable for small vehicles such asMini car, motorcycle, etc.The tire pressure gauge adopts pressure sensing technology, with high measurement accuracy (error less than 0.05%) and long service life.Timely test the tire pressure with a tire pressure gauge, so that drivers can know the tire pressure of their favorite car in time.The pointer type operation is simple, the digital reading is convenient, and the alarm type does not display the tire pressure value.Each tire pressure gauge has a certain pressure measurement range. Generally, only 0-100 PSI is needed for household use, and no heavy load tire pressure gauge for trucks is needed. The price ranges from 12 yuan to 100 yuan.
classification
Double head tire pressure gauge
Mini Tire Pressure Gauge
Pencil Tire Pressure Gauge
Dial Tire Pressure Gauge
Digital Gauge Inflator Gauge
Dual Wheel Tire Gauge
working principle
Inside the main tube of the tire pressure gauge, there is a piston with good sealing performance, and the inside of the tube is very smooth.The piston is located at one end of the tube body, and the plug is located at the other end.The piston and the plug are connected by a compression spring, which is used to push the piston to the left side of the tube body.
When the tire pressure gauge is pressed on the valve stem, the pressurized air in the tire will rush into the pressure gauge and push the piston to the right.The stroke of the piston then corresponds to the pressure in the tire.The pressurized air pushes the piston to the right, and the spring pushes the piston back to the left.When the tire pressure gauge is released from the valve stem, the pressurized air will stop flowing, and the spring will immediately push the piston back to the left.The ball on the left side of the tire pressure gauge is concave.The opening of the ball is used to engage the valve stem of the tire.If you look into the opening, you will see a rubber sealing block and a small fixing pin.The rubber sealing block is used to press the flange of the valve stem to prevent air leakage during measurement.The fixing pin is used to press down the valve core in the valve stem to allow air to enter the tire pressure gauge.The air flows around the fixing needle, passes through the concave part in the sphere, and then enters the piston chamber.
There is a calibration rod inside the pipe body for reading the pressure. The calibration rod is located on the upper part of the piston, but it is not connected to the piston, but to the plug.When the piston moves to the right, it pushes the calibration rod.When the pressure is released, the piston will move back to the left, and the calibration rod will stay at its maximum displacement, then the pressure reading can be taken.
usage method
1. Find a stable position and place the tire pressure gauge on the valve stem.
2. Press the tire pressure gauge tightly to seal it with the valve stem, and air will enter the tire pressure gauge from the tire.Note that the needle inside the pressure gauge should be aligned with the valve core in the valve stem to release air from the tire.
3. Read the pressure of the tire pressure gauge.
After frequent use of the tire pressure gauge, the indication may be inaccurate, the zeroing mechanism may fail, and the reading device may be stuck.Through the automatic control of the air source pressure and the alternate action of the automatic zeroing device, the endurance test of the tire pressure gauge can be completed automatically, and the accuracy can be tested directly, which is very reliable and convenient.This project provides technical guarantee on test means for accurately evaluating the performance of tire pressure gauge[1]。In order to solve these problems of tire pressure gauge,The new AireekAC2000 electronic tire pressure gauge launched by Gemeo Company is equipped with human-computer control and electronic instruments, which can improve the tire pressure measurement and make the tire pressure measurement more accurate.It is not only convenient to use, but also has the characteristics that the linear direct reading barometer used today has not: the unique LDC display installed in the scratch resistant concave lens can directly and clearly display the pressure reading;The adopted electronic pressure sensor can make the pressure measurement accurate to 3.445kPa and extend the service life of the barometer[2]。
matters needing attention
When using the tire pressure gauge, remind users to pay attention to the following aspects:
1. The vehicle shall be parked on the flat ground, and the tire pressure must be measured when the vehicle is cold;
2. Remove the valve cover of the tire, and vertically press the pressure measuring valve of the tire pressure gauge with force aligned with the valve on the tire.The pressing speed needs to be rapid so as not to cause air leakage in the tire;
3. Determine whether the tire pressure meets the requirements according to the tire pressure requirements at the door side and the driver's experience;If the tire pressure is too high, the tire pressure gauge can be used to deflate;If the tire pressure is too low, the vehicle mounted inflation pump shall be used to replenish air to the safe tire pressure immediately, and the accurate tire pressure shall be re measured and checked;
4. Replace the valve cap;
5. Check the tire pressure at least once a month.Before you are not familiar with the operation of measuring tire pressure, you can measure it several times to ensure that the reading is correct.
Empty box barometer
Announce
edit
brief introduction
Empty box barometerAlso called solid metal barometer.It is a portable measurementatmospheric pressureInstrument.It uses the pressure of the atmosphere acting on the empty metal box (the box is close to vacuum) to deform the empty box, and drives the pointer through the lever system to make the pointer point out the value of the air pressure at that time on the dial.Empty box barometer is inferior toMercury barometerPrecise. Generally, stations are only used as reference instruments and are mostly used for field observation.
Features
Empty box barometerIt is a kind of atmospheric pressure measuring instrument with deformation element as induction.It is widely used in meteorology, military, aviation, navigation, agriculture, surveying, geology, industrial and mining enterprises, scientific research and other fields, and has become a conventional instrument for measuring atmospheric pressure, with the advantages of convenient carrying, accurate measurement, wide range of pressure measurement, simple use and maintenance, and no mercury pollution.
Instrument structure
Serial number of instrument structure
Part name
1 Pointer
2 Pointer shaft
3 hairspring
4 Pointer shaft support plate
5 Dial
6 Reflector
7 Dial fixing column
8 Upper bracket
9 Bracket fixing column
10 Temperature gauge
11 Sector gear
12 Intermediate shaft
13 Adjusting screw
14 Counterweight
15 Connecting rod
16 Empty box group
17 Regulator
18 Lower pallet
19 Mounting screws
working principle
Empty box barometerIt is a thin film empty box made of elastic metal as the sensing element, which converts the atmospheric pressure into the elastic displacement of the empty box, and drives the pointer through the lever and transmission mechanism.When the pointer is deflected clockwise, it will indicate the change amount of air pressure increase. Conversely, when the pointer is deflected counterclockwise, it will indicate the change amount of air pressure decrease.Elastic stress and atmospheric pressure of empty boxphase equilibriumThe pointer will stop rotating when the air pressure indicated by the pointer is at that timeatmospheric pressureValue.
Technical performance and specifications
A Measurement range: 800 ～ 1064hPa
B Operating temperature range: - 10~+40 º C
C After temperature, indication and supplementary correctionmeasurement errorNot more than 2.0hPa
Before reading, gently tap the instrument housing or surface glass with your fingers to eliminate friction in the transmission mechanism.
During observation, the pointer overlaps with the mirror pointer. At this time, the value indicated by the pointer is the air pressure indicating value, and the reading is accurate to one decimal place.
Read the temperature indicated value on the barometer, accurate to one decimal place.
Calculation of air pressure value: the air pressure indication value read on the instrument can only be used after the following correction.
Temperature correction: because the change of ambient temperature will affect the elasticity of instrument metal, temperature correction must be carried out.The temperature correction value can be calculated as follows:
△Pt = a.t
Where: △ pt - temperature correction value
A -- Temperature coefficient value (attached to the verification certificate)
T ―― reading of thermometer
Indication correction, due to the nonlinearity of the empty box and its rotation, will occur when the air pressure changesIndication errorTherefore, indication correction must be carried out.Calculation method: according totestThe indication correction value on the certificate is within the pressure range corresponding to the pressure indication value:Interpolation methodCorrection of calculated valueIndication△PS。
Supplementary correction: in order to eliminate the influence of the residual deformation of the empty box on the indication, the supplementary correction value △ pd obtained from the verification certificate
The corrected air pressure value can be shown by the following formula:
P = ps + (△pt +△ps +△pd)
matters needing attention
The instrument must be placed horizontally during operation to prevent reading error caused by tilt.
Users shall not take out the instrument in the plastic housing to avoid unnecessary damage.In case of failure, please submit it to the meteorological measurement organization or working principle.
As the supplementary correction value of the instrument changes with time, the supplementary correction value shall not exceed the service life of six months. If it exceeds the service life, it must be verified again.
The user shall not adjust the adjusting screw without authorization to avoid increasing the error of the instrument.
Storage, transportation and packaging
The instrument shall be stored in a dry, ventilated place without corrosive gas and severe vibration.
The instrument can be transported by any method other than air transportation.
The packaging box of the instrument must be filled with shock absorber, and the words such as "handle with care", "precision instrument" and "do not invert" shall be marked outside the box.
measurement result
According to JJG 272-2007 Empty Box Barometer and Empty Box Barometer, the metrological verification regulation[3]The uncertainty of the measurement results must be given in the verification results of the empty box barometer, so at present all provincial meteorological measurement verification departments need to do this work. In view of this actual situation, we will describe the evaluation process of the measurement uncertainty of the empty box barometer for reference[4]。
