Description
1:working principle
The air pressure switch has two detection ports, namely the positive pressure detection port and the negative pressure detection port, and its cavity is also divided into a positive pressure cavity and a negative pressure cavity.The two cavities are separated by a membrane, and when there is a pressure source, the membrane moves to trigger the micro switch to achieve the purpose of on/off.Usually the sampling of the air pressure switch adopts the negative pressure detection port, and the sampling device is installed in the negative pressure area of the volute of the strong exhaust fan.The sampling port of the sampling device is a tube with an oblique angle, which is at a certain angle with the wind direction, and the detected pressure values are also different with the change of the angle and the change of the wind speed.
2： Main material names and specifications
|
No. |
Part name |
material |
Material Specifications |
Brand and origin |
|
1 |
Micro Switch |
Stainless steel |
SSS301 |
China |
|
2 |
Micro switch (contact) |
compound contact |
compound contact |
China |
|
3 |
diaphragm |
Fumed silicone rubber |
|
Import |
|
4 |
Cover |
PC |
|
China |
|
5 |
bottom cover |
PC |
|
China |
|
6 |
Mount |
Electrolytic plate |
1mm |
China |
3、Electrical properties
|
No. |
Item |
Test Conditions |
standard |
|
4.1 |
Contact resistance |
Use a DC bridge with an accuracy of not less than 0.05 or other equipment with the same accuracy to measure the resistance between the two terminals, and use the voltage drop method to measure. Application part: between terminals。 |
≤100mΩ |
|
4.2 |
Insulation resistance |
Test voltage: 500VDC, measured after 60 seconds of application time. Application site: between terminals, between terminal - shell. |
500MΩ |
|
4.3 |
Pressure resistance |
1000VAC 50/60Hz voltage application time 60S, leakage current 0.5mA. Application site: between terminals, between terminal - shell. |
No breakdown |
4、mechanical character
|
No. |
Item |
Test Conditions |
standard |
|
5.1 |
Action pressure value (on) |
Apply negative pressure at the negative pressure end, the pressure value when the normally closed contact is turned on |
-70PaMax |
|
5.2 |
Close pressure value (off) |
When the pressure on the negative pressure side drops, the pressure value when the normally closed contact is disconnected |
-50 PaMin |
|
5.3 |
Terminal strength |
Apply static push or pull force along the terminal axis for 60S |
10N no damage |
|
5.4 |
vibration |
It is fixed on a vibration inspection table with sufficient strength, and it is continuously vibrated for 30 min each at a speed of 3 mm amplitude and a frequency of 10 Hz in the up and down, front and rear, and left and right directions. |
Contact resistance, withstand voltage performance, and insulation resistance meet the requirements of the 4requirements. The operating pressure value and the closing pressure value can deviate by 20%. |
|
5.5 |
be under attack |
Freely drop the product from a height of 800mm on a solid horizontal surface such as concrete, stone or steel plate, and drop it three times from top, bottom, left, right, front and back respectively. |
|
|
5.6 |
Air tightness |
Under the test pressure of 1 kPa, connect the air pressure output pipe of the airtight leak detector to the positive pressure port or negative pressure port of the air pressure switch. |
Leakage ≤0.1 L/h at 1 kPa air pressure |
5、Environmental adaptability
|
No. |
Item |
Test Conditions |
standard |
|
6.1 |
low temperature |
Place in -25℃±3℃ incubator for 24h, take out and place at room temperature for 1h, test within 1h。 |
Contact resistance, withstand voltage performance, and insulation resistance meet the requirements of the 4requirements. The operating pressure value and the closing pressure value can deviate by 20%. |
|
6.2 |
high temperature |
Place in a +85℃±3℃ constant temperature oven for 24h, take it out and place it at room temperature for 1h, and test within 1h. |
|
|
6.3 |
6.3 Temperature Variation |
Put it in the incubator at -25℃±3℃ for 0.5h, take it out and put it in the room temperature environment for 2 min~3min, then put it in the incubator at +85℃±5℃ for 0.5h, take it out and put it in the room temperature environment placed in the middle for 2 min to 3 min, and carried out 5 consecutive cycles. |
|
|
6.4 |
Salt spray resistant |
Place for 24 h according to GB/T 2423.17. |
No rust |
6、Durability
|
No. |
Item |
Test Conditions |
standard |
|
7.1 |
Durability
|
Under the condition of 0.1 A, 30 VDC DC load, a pressure of -100 Pa was applied, and the switch was continuously switched 100,000 times at a rate of 7 times/min to 10 times/min. |
Contact resistance≤200mΩ Contact resistance, withstand voltage performance, and insulation resistance meet the requirements of the 4 requirements. The operating pressure value and the closing pressure value can deviate by 20%. |
