The working principle of the explosion-proof positive pressure room is to maintain positive pressure in the shell of the instrument room through the ventilation system to meet the explosion-proof technical requirements, so as to achieve the purpose of making all electrical equipment in the instrument room explosion-proof. Electrical equipment outside the control of the explosion-proof system must be explosion-proof electrical equipment, and electrical equipment within the control of the explosion-proof system is controlled by the explosion-proof system. When the main power of the instrument room is turned on, the system automatically turns on the explosion-proof blower system first, and the explosion-proof blower draws fresh air 30 meters away from the wellhead into the instrument room to replace the air in the instrument room. After 3 weeks of replacement, if the control conditions are met, the main power supply is automatically turned on, and then the power control power supply can be turned on to turn on the electrical equipment in the instrument room. During the opening process, if one of the convenient control conditions is not met during the operation of the fire instrument, an alarm will be issued. If the control conditions are still not met within the specified time, or the alarm upper limit is directly reached, the system will automatically shut down, thereby achieving the purpose of convenience.
Composition of the convenient control system: It consists of an intelligent control system, an air intake system, an air flow sensor, an indoor and outdoor pressure difference sensor, a temperature sensor, a hydrogen sulfide sensor, and a hydrocarbon gas detection sensor.
Explosion-proof analysis huts are a technology that became popular in the mid-1980s. The Eagle Power Explosion-proof Industry Alliance has launched explosion-proof huts, explosion-proof analysis huts, positive pressure explosion-proof rooms, explosion-proof stations, and explosion-proof safety analysis huts.
It integrates the combination, set, and installation of industrial online instruments, and is widely used in oil refining and chemical companies. The standardized and professional design of the on-site analysis room makes the on-site installation and maintenance of analytical instruments more convenient, and provides a good operating and operating environment for the instruments.
While ensuring the required use environment and the accuracy of the analytical data, it improves the use cycle of the analytical instrument, has been increasingly used in process equipment, and has been widely used in enterprise safety performance.
1. Scope of application of explosion-proof positive pressure cabin
An analysis cabin product with positive pressure ventilation and explosion-proof. It is an explosion-proof industrial product that can be used in hazardous places such as Zone I and Zone II. As long as electricity and gas are provided on site, online instruments can work safely, stably and reliably in hazardous places. At the same time, the staff performing operations in the analysis room can also be guaranteed to be safe. It is used in the production of oil refining, chemical industry, metallurgy, pharmaceutical industry and light industry, and provides on-site safe installation space and protection for various process gas online analyzers and various online water quality analyzers.
Applicable to hazardous places in Zone 1 and Zone 2 of explosive gas environment;
Applicable to IIA and IIB explosive gas environments;
Applicable to environments with temperature groups of T1-T4;
Applicable to the production of oil refining, chemical industry, metallurgy, pharmaceutical industry and light industry, and provides on-site safe installation space and protection for various process gas online analyzers and various online water quality analyzers.
2. Explosion-proof positive pressure cabin size
Manufactured according to user needs. Generally, the cabin's outer dimensions are 3000mm (length) × 3000mm (width) × 3000mm (height).
The cabin is a non-standard product. Its size can be determined according to the number, type, system complexity and operation and maintenance space of the analyzer, and appropriate margin should be left. Limited by long-distance transportation conditions, its external dimensions are generally as follows:
Length: outdoor main body 2.5~6.5m (considering the standard steel length and the strength of the hoisting and transportation structure, the length of a single analysis cabin should not exceed 6.5m. If the length is 6.5m, a combined structure can be used, split and made, and then combined into one after transportation to the site. Two analysis cabins can also be used to achieve this).
Width: outdoor main body 2.5m, the widest should not exceed 3.0m (limited by the width of road transportation, the width should not exceed 3.0m).
Height: outdoor main body 2.5~3.0m (limited by the height when passing through overpasses and tunnels), indoor net height 2.2~2.8m.
3 .Mechanical structure and material requirements of explosion-proof positive pressure huts
(1)Frame, base and roof
The frame, base and roof of the analysis hut are metal components, welded with steel sections, and should have sufficient strength and rigidity to ensure that the analysis hut does not deform during load, lifting, translation and transportation.
The main frame of the base should be made of 12#~20# channel steel, and two 10#~12# channel steels or I-beams are used as support beams under the floor keel. The main frame, floor keel and support beams should be welded to ensure that the floor does not vibrate when maintenance personnel walk indoors.
The roof frame and main beam should be made of 10#~12# channel steel, and 8#~10# channel steel should be used as the main beam and roof keel support in the width direction. They should be welded to prevent distortion. The roof should have a certain inclination, with a slope of at least 4%. It can be A-shaped or one-sided slope structure. Flat roof is not allowed to prevent rainwater accumulation.
(2)Inner and outer walls and inner and outer ceiling panels
External wall panels should be made of 1.5mm#~2.0mm steel plates. The ∏-shaped plate assembly structure can be used to form the exterior wall. If the welding process can be guaranteed, the ribbed galvanized plate welding structure can also be used to form the exterior wall surface. The exterior wall panels with ∏-shaped plate assembly structure should use stainless steel plates (304SS, stainless steel brushed laminated plates are recommended), or galvanized steel plates can also be used. When galvanized steel plates are used, the surface must be sprayed, and the spray color is white or gray.
Inner wall panels and ceilings should be made of 1.5mm#~2.0mm steel plates. Galvanized steel plates or cold-rolled steel plates are used as electrical shed materials. Stainless steel plates can also be used according to user requirements. When galvanized steel plates or cold-rolled plates are used, the surface must be sprayed. The spray color is: white glossy paint for the ceiling and white matte paint for the inner wall panels.
The roof panel must be effectively designed for rain protection. The snap-on assembly rain protection design or flat welding rain protection design can be used. The material is made of 1.5mm#～2.0mm stainless steel plate to ensure the long-lasting corrosion resistance of the roof surface. The load-bearing capacity of the outer top is ≥250kg/m2 (the weight of two people) and no permanent deformation occurs.
(3)Insulation layer
The flame-retardant insulation material (mineral wool, etc.) is filled between the inner and outer walls and the inner and outer tops. The thickness of the insulation layer is generally 70～75mm (3in). It should be thickened to 80～85mm in extremely cold or hot areas.
(4)Floor
The floor should be a non-slip metal plate, preferably made of 4～6mm steel plate. The material can be patterned stainless steel plate, patterned galvanized steel plate or hot-rolled steel plate according to user requirements. The surface of galvanized steel plate or hot-rolled plate must be sprayed. The spray color is generally gray. If necessary, a layer of anti-static plastic plate can be added.
The interior of the hut should avoid dead corners and grooves where gas may accumulate. Appropriate manual or automatic exhaust holes should be opened at high and low places of the hut to prevent gas accumulation. The sample pretreatment unit, carrier gas cylinders, standard gas cylinders and laboratory manual analysis sampling points should be located outside the cabin.
4. Power distribution of explosion-proof positive pressure cabin
The lighting, ventilator, air conditioner, maintenance socket and other public equipment in the analysis cabin are powered by industrial power supply. The analyzer system, installation detection alarm and interlocking system are powered by UPS power supply.
5. Safety detection and alarm system for explosion-proof positive pressure cabin
Combustible gas detectors Use products with integrated structure of detection probe and signal transmitter, and have local display header and contact signal output.
Toxic gas detectors When the sample or the surrounding gas contains toxic components, a toxic gas detection alarm must be installed, and the requirements are the same as those of the combustible gas detection alarm.
Micro differential pressure transmitters The analysis cabin is equipped with different numbers of micro differential pressure transmitters according to the internal volume to detect the positive pressure in the analysis cabin. The principle of the signal provided by the micro differential pressure transmitter to the PLC controller is 3 out of 2, that is, the PLC cuts off the power supply of the non-explosion-proof electrical equipment in the analysis cabin through the pressure signal. If there are 3 micro differential pressure transmitters in the cabin, if more than 2 of them give a pressure value lower than the safety requirement at the same time, the PLC will give a command to cut off the power supply of the non-explosion-proof electrical equipment in the analysis cabin. Sound and light alarm devices Refers to sirens and warning lights (rotating flashing type), which are installed outside the cabin.
Explosion-proof alarm control box It is equipped with a small programmable controller (PLC or processor) and various indicator lights and buttons on the panel. Its function is to control the safety detection alarm system, realize local alarm (inside and outside the cabin), control room alarm and interlocking function (such as starting the fan and opening the instrument air for exhaust).
5.1.System composition: The online explosion-proof analysis room can be widely used in metallurgy, chemical industry, textile, oil refining and other industries. It is an explosion-proof industrial product that can be used in hazardous places such as Zone I and Zone II. As long as electricity and gas are provided on site, online instruments can work safely, stably and reliably in hazardous places.
At the same time, the staff performing operations in the analysis room can also be guaranteed safety. The system consists of the following five parts:
A: Analysis room main body (double-layer structure, filled with thermal insulation and fireproof materials in the middle);
B:Indoor hazardous gas concentration monitoring system;
C :Sound and light alarm interlocking system;
D :Instrument power supply system; E Public power supply system;
6. Structure and main technical parameters of positive pressure explosion-proof analysis room
Structural form of the room: adopt internal and external steel structure, assemble the analysis instrument, pretreatment and control unit in the analysis room, and install the analysis room on site. The sampling probe is installed in front of the outdoor pressure reduction station. The main body of the analysis room adopts internal and external steel structure, both of which are cold-rolled (or stainless steel) steel plates, the base adopts No. 10 channel steel, and the surrounding keel square steel structure. The inner and outer plates are sprayed with plastic, and the middle layer is 70mm thick, which is filled with flame retardant, heat preservation and heat insulation materials. Explosion-proof air conditioners are installed indoors to adjust the indoor temperature. The power distribution system is a pipeline system equipped with an explosion-proof distribution box. The lighting system uses explosion-proof emergency fluorescent lamps. The analysis room also has ventilation, air exchange and filtration devices. Single door structure, equipped with glass viewing window and escape door lock. Using special processing technology, all achieve the functions of sealing, corrosion resistance, dust prevention, temperature control, etc.
Positive pressure explosion-proof analysis room applicable scope:
Indoor ambient temperature: 5℃~+45℃;
Ambient humidity: relative humidity not more than 95%;
Altitude: not more than 2000m;
The temperature of the analysis room shall be heated or air-conditioned according to the requirements of the analytical instruments installed inside.
The inlet of the air duct of the analysis room shall be in a non-hazardous area.
Installation and use conditions:
Ambient temperature: -20℃~40℃;
Power supply: AC220±10% 50Hz;
Atmospheric pressure: 50 KPa-- 106 KPa;
Altitude: < 2000m;
No strong vibration;
7. Main technical parameters of positive pressure explosion-proof analysis room:
A: Explosion-proof level: ExdⅡBT4~ExdⅡCT6, the production level is determined according to user requirements. B: Sound and light alarm when the concentration in the analysis room exceeds the limit (25%LEL);
C: Power supply: 220VAC±10%, 50Hz, 20A;
D: Protection level: ≥IP56E: Normal internal pressure: 30-100Pa;
8. Product features:
Equipped with explosion-proof distribution box and junction box;
The wiring method is determined according to user requirements;
Explosion-proof air conditioners can be installed according to user requirements to ensure the temperature in the room, and explosion-proof electric heaters or steam heating equipment can also be installed in the room;
Explosion-proof fluorescent lamps are installed inside;
Workbenches can be installed inside according to user requirements;
Analytical instruments can be customized by users;
The analysis room has the advantages of shockproof, anti-static, anti-spark, dustproof, and anti-interference, providing a good operating environment for the instrument and enhancing the reliability of the system;
The analysis room can relatively centrally install various process analysis instruments used in various industrial fields, use the public works of the analysis room for unified power supply, and uniformly transmit signals with the control room;