On formal explosion-proof electrical equipment will be Ex logo, and each explosion-proof electrical equipment will have a special explosion-proof marks.

1: China and the international electrotechnical commission is the Ex explosion-proof marks, shows that listed in the electrical equipment in accordance with the GB3836 and IEC60079 one or more of the explosion-proof type

2: all kinds of explosion-proof type common symbols are as follows:

Type flameproof "d," increased safety "e", in the "I", filling sand mold "q", positive pressure type "p", immersion type "o", and "n" type, encapsulation type "m"

In the example is flameproof explosion-proof electrical equipment

Category 3: equipment symbols

Ⅰ categories: (1) the gas generating coal mine electrical equipment

(2) A and B Ⅱ Ⅱ, Ⅱ C: besides Ⅰ class of other electrical equipments used in explosive gas environment, namely with electrical equipment factory

Note: Ⅱ B equipment can be used for Ⅱ A condition of equipment, in the same way, Ⅱ C devices can be used for Ⅱ A and B Ⅱ use; Conditions, therefore, the level of explosion-proof Ⅱ C > Ⅱ B > Ⅱ A

4: Ⅱ kind of electrical equipment, said temperature group symbols is as follows:

Ⅱ class the highest surface temperature in the electrical equipment categories: T1 maximum surface temperature 450 ℃, T2 the highest surface temperature of 300 ℃, T3 top surface temperature of 200 ℃, T4 the highest surface temperature of 135 ℃, T5 the highest surface temperature of 100 ℃, T6 maximum surface temperature of 85 ℃

5: equipment protection level is divided into "Ga", "Gb" and "Gc", "Ma" or "Ma".

Equipment protection level (EPL) : according to equipment become the possibility of ignition source and explosive gas environment, explosive dust and coal mine methane explosive environment have different characteristics and fixed level of protection of the equipments.

- Ma level (EPL Ma) : the installation of equipment in coal mine methane explosive environment, has a "very high" level of protection, the level has enough safety, make the equipment in normal operation, the expected or rare fault, fault equipment even in the presence of gas suddenly charged cases are still can't be light source.

- Mb level (EPL Mb) : the installation of equipment in coal mine methane explosive environment, with a "high" level of protection, the level has enough safety, make the equipment in normal operation or in gas power suddenly appeared and equipment between the time of fault conditions can't be expected ignition source.

- Ga level (EPL Ga) : explosive gas environment with equipment, has a "very high" level of protection, in normal operation, the expected failure or rare when a failure is not a light source.

- Gb level (EPL Gb) : explosive gas environment with equipment, has a "high" level of protection, under the condition of normal operation or the expected failure is not a light source.

- Gc level (EPL Gc) : explosive gas environment with equipment, has the "average" level of protection, not in the normal operation of the light source, also can take some additional protective measures, ensure that often occurs in the ignition source is expected (such as failure of lamps and lanterns) under the condition of not effective

Representing the degree of cold and hot objects physical quantities.

Relative humidity, vapor pressure in the air and the percentage of the saturated vapor pressure. The absolute humidity of wet air and same temperature could reach the ratio of the maximum absolute humidity. Wet vapor in the air can also be expressed as the ratio of the saturation pressure of the water pressure with the same temperature.

Humidity, atmospheric dry degree of physical quantities. In a certain temperature in a certain volume of the less water in the air, the air is dry; The more water vapor, the air is humid. The degree of dry wet air is called "moisture". In this sense, commonly used absolutely

Test environment is in a state of high temperature and high humidity for a long time, or have the corrosive substance probe dewing corrosion damage.

Make sure the sensor output signal and the connection mode of secondary instrument is correct, then checks whether display instrument internal parameter Settings and the parameters of the sensor.

1, avoid the easy heat transfer and can directly cause and zone of temperature difference for the installation, otherwise it will cause the temperature and humidity measurement is not accurate.

2, installed in the area of environment is relatively stable, avoid direct sunlight, away from the window and air conditioning, heating and other equipment, avoid straight to the window

1, if there is dirt on the air temperature and humidity sensor, should use a soft brush to clean, not water cleaning, replacement of filter paper in a timely manner. It is important to note that the maintenance, when clean sensor cannot be placed outside the screen.

2, check the desiccant in the atmospheric pressure sensor static stomatal color is blue, if there's any impurities and air inlet. If the blue means to replace desiccant desiccant color.

3, clear the dust on the rainfall sensor on a regular basis, sandstone, grass, insects, etc., can flush of skip caused by pollutants.

4, in order to ensure the measure precision of the wind sensor, avoid error, should be to the wind sensor for regular cleaning and maintenance. If the bearing wear, etc., are considered for replacement.

5, check whether the surface temperature sensor and shallow ground temperature sensor to the surface soil changes, to ensure that the sensor in the right place and cable is in good condition.