Hx-wr explosion-proof thermocouple

A. We mentioned

Flameproof thermocouple is according to Q/ZZ HHX002-2012 HX - WR flameproof thermocouple, GB3836.1-2010 "explosive environment, part 1: general requirements for equipment and GB3836.2-2010" explosive environment part 2: the flame-proof shell "d" protection equipment "provisions, the explosion-proof marks for the Ex d Ⅱ C T6 Gb.

This product is used in explosive gas, steam, the mist a sensor measurement of the factory environment, and is often used to display instrument, adjusting instruments, transmitter and so on, with all kinds of gas in the direct measurement of all kinds of production engineering, the temperature of the liquid medium.

The product is inspected by the national quality inspection center of explosion-proof electrical products and has obtained the explosion-proof certificate. The explosion-proof certificate number is CNEx13.

Second, the principle of

1. Temperature measurement principle

The principle of thermocouple is based on two different components of the conductor at both ends of the connection to form a network, such as the different temperature of the two terminals, the physical phenomena that generate thermal current in the loop.

The thermocouple is composed of two different conductors (thermal electrodes) A li B, and their end T1 is welded to each other, forming the measuring end T1 (also known as the working side) of the thermocouple. Insert it temperature of the medium under test, and the other end of the thermocouple T0 (reference end or free end) is connected to the display instrument, if exist with the reference of the measuring junction of the thermocouple temperature difference, the display instrument will point of thermocouple thermoelectric emfs.

The thermoelectric electromotive force of thermocouple increases as the temperature of the measuring end increases, and its size is only related to the temperature of the thermocouple and the temperature of the thermocouple, which is independent of the length of the thermal electrode and the diameter.

2. Explosion-proof principle

Flameproof explosion-proof structure is based on the maximum test security clearance, through the flame-proof joint surface quenching and cooling effect, make the combustible mixture inside the flame-proof shell explosion and flame-proof shell is not damaged, and does not cause external lit the principle of design and manufacture of explosive gas.

This product is suitable for the existing Ⅱ, Ⅱ B, Ⅱ C level, T1 ~ T6 group 1 zone and 2 zone the explosion of the combustible gas or vapor and air form

Area 1 and 2 of the sex mixture.

The model specifications and meanings of the thermocouple are as follows:

1. Measuring range: 0 ~ + 800 ℃

2. Explosion-proof marks: Ex d Ⅱ C T6 Gb

3. Protection level: IP65

4. Scale: table 1

5. Response time: 90 ~ 180s

6. Rated voltage: 24VDC

7. Insulation resistance:

(1) under normal temperature insulation resistance: when the ambient air temperature is 15 ~ 35 ℃ and relative humidity under 80% when, between the thermocouple protection tube temperature sensing element and the insulation resistance of not less than 100 m Ω.

(2) high temperature insulation resistance: thermocouple in 300 ~ 500 ℃, the temperature sensing element and the insulation resistance between the protecting tube not less than 2 M Ω.

8. The environmental conditions are as follows:

A atmospheric pressure of 80 ~ 110kPa;

Ambient temperature: b - 20 ~ 40 ℃;

C air maximum relative humidity is not more than 80% (+ 25 ℃);

D is A and B Ⅱ Ⅱ, Ⅱ C level, T1 ~ T6 group 1 zone and 2 zone of flammable gas or vapor and air form explosive mixture of place;

E in a gas or vapor environment without damaging insulation;

F where there is no significant shaking and impact vibration;

The basic structure of the explosive thermocouple is mainly composed of the components of the sensing element, the junction box, the protective pipe and the installation of the fixed device. The basic structure is shown in the general assembly drawing wr.001.001-14.

1. Sensor components

The temperature element of this product is composed of thermal electrode, compensation conductor, ceramic insulating tube and wiring seat.

2. The junction box

The box seat and the box cover are not more than 7.5% in magnesium and titanium. The tensile strength is greater than the aluminum alloy of 120N/mm2, which is connected by a thread separation joint. Tighten the lid of the box after installation. No opening of the box cover before disconnecting the power supply of the thermocouple. The junction box is connected to the protective pipe by a thread separation joint. The junction box adopts the pressure-tight nut to introduce the device. The cable shall be fitted in the proper size, so that the sealing ring of the introduced device can be clamped into the cable, and no space shall be left.

3. The protection tube

All made of stainless steel, good temperature resistance, corrosion resistance and sufficient mechanical strength.

The design insert depth of the protection tube of this model is 150mm. Besides, the user can provide specific dimensions according to the requirements.

4. Install fixtures

Install the fixed device for the nut type fixed or flange fixed, as shown in figure wr.008.1-2.

V. installation and use

1. The selection of flame - proof thermocouple

The proper selection of explosion-proof instrument is one of the important conditions for the safety of the factory, and it is also related to whether the instrument is economical and practical.

(1) selection principle:

The user chooses the partition type thermocouple to adapt to the division of the explosive mixture at the temperature measuring site, the group and the dangerous area.

(2) explosion-proof marks

The symbol for the Ex explosion-proof product d Ⅱ C T6 Gb.

2. Installation requirements:

The site installation of this product shall conform to the relevant provisions of gb3836.15-2000 "electrical equipment for explosive gas environment" part 15: electrical installation (except coal mines) in dangerous places.

The installation site of the thermocouple should be avoided near the furnace door. The junction box of the thermocouple shall not meet the container wall of the measured medium, and shall be installed in the place where the junction box is well ventilated. The wiring hole of the junction box of the thermocouple should be down to the hole with water proof, dust and debris.

3. Connection:

The junction box is equipped with internal and external grounding bolts to ensure safety and installation.

The introduction of cable insulation should be adopted (preferably shielding) copper wire, cable diameter should be compatible with sealing ring, copper wire cross-sectional area depending on the distance between the thermocouple and secondary instrument, but shall not be less than 1.5 was, resistance of the wire should be stipulated in the technical condition of secondary instrument data registration (generally for 5 Ω).

4. Use of explosive thermocouple:

The thermocouple is used to measure temperature, and the thermocouple is installed at the test site. After a period of time, the actual temperature of the measured place can be measured. In order to reduce the heat conduction and heat exchange of the measured place and the external environment, the circulation of the measured medium should be increased, and the convection heat transfer between the thermocouple and the measured medium is increased under the conditions of work pressure permitting. Increase thermocouple insertion depth. When used, the thermocouple should be matched with the second instrument of the corresponding indexing number to properly display and control the temperature, and a thermocouple should not be used at the same time with two secondary instrument connections.

5. Precautions:

(1) check whether there is an explosion proof mark and explosion-proof certificate number of the product shell.

(2) check whether there are mechanical damage to the products in the transportation, installation and other links, especially the surface of the explosion joint and the anti-loosening device. If there is damage, loose can affect the explosion - proof performance.

(3) check the explosion-proof category, temperature group, and the use of the site and the requirements of the site of the explosive gas mixture.

(4) whether it has internal and external grounding screws and signs.

(5) it is strictly forbidden to change the parts that are relevant to the explosion-proof and ensure the explosion-proof property.

(6) it is forbidden to open the cover in a dangerous place, and the power supply of the thermocouple must be turned off before it can be opened. The installation should be checked and checked, the lid of the box should be tightened, the protective screw of the top of the box can be used in the rear.

(7) to dismantle or replace thermocouple, must be the insert part reduced to under 80 ℃ temperature or the temperature limit of the following permitted under the conditions of use, can be removed or replaced.