Design scheme for a positive-pressure explosion-proof control cabinet for petroleum drilling rigs.
PetroleumDrillingMachineUsersPositive-pressure explosion-proof control cabinetIsaccording toGB3836.1《Explosive GasEnvironmentUsersElectricalequipment Part 1: General Requirements》；GB3836.2《Explosive GasEnvironmentUsersElectricalequipment Part 2:Flameproof Type"d"》、 GB3836.5《Explosive GasEnvironmentUsersElectricalequipment no.5Part: Positive Pressure Enclosure Type"p"》、；The positive-pressure explosion-proof electrical control cabinet is manufactured in accordance with GB3836.15 "Electrical Apparatus for Explosive Gas Atmospheres - Part 15: Electrical Installations in Hazardous Areas (Other Than Mines)", with the explosion-proof marking: ExpxIICT4. This control cabinet has passed inspection by a nationally authorized quality supervision and inspection department and has obtained the product explosion-proof certificate. This electrical cabinet is mainly suitable for use in Zone 1 and Zone 2 explosive gas atmospheres in fields such as petroleum, chemical, metallurgical, and pharmaceutical industries, where the air contains explosive gas mixtures of Class IIC and below, serving as electrical control equipment.
Positive-pressure explosion-proof control cabinetbasicparameter
Electric Source: 220VAC、380VAC/50HZ
Rated Current: 630A
Ingress Protection (IP) Rating: IP65
Explosion-proof Marking: ExpxIICT4
Air SourceVariousVarious: Clean、safetyAerospaceStation
Air Sourcepressure: 0.4～0.8 MPa
operationPositive Pressure: 50 Pa～300Pa
Positive PressureCavityNetAsArea: ≤510 L+510L+100L
BlowingSweepTime: 30min
High PressureDrainStation: GreaterIn400Pa
LowPressureAdvancedStation、Alarm: SmallIn50Pa
structure And Principle
Positive-pressure explosion-proof control cabinetmainlyWithElectricControlCabinet、StationControlCabinet、LeftOperatePlatformThreeProduction。The main body of the electrical cabinet consists of a positive-pressure enclosure, a positive-pressure gas path system, and a flameproof control box.。
The positive-pressure enclosure is an airtight enclosure made of 2.5mm stainless steel plates formed by edge folding and welded assembly.。Because it can maintain the pressure of the internal protective gas higher than the pressure of the external explosive gas atmosphere, it can effectively prevent external explosive gas mixtures from entering the interior of the enclosure.。A red "ExpxⅡCT4" marking plate is located in a prominent area on the front of the pressurized enclosure.。
inPositive PressureEnclosureSupremeInstallationWithifDryCable EntryTriggerOutputdevice、StationLineConnector、ElectricApplianceSwitchEtc.，Thesesomedevice的InstallationInvincibleHighlyBreakBadPositive PressureEnclosure的Gas Tightperformance；
Positive PressureStationLinesystemByDuringFilterReducePressureUnitComponents、Energy-savingMainstreamValve、Explosion-proof electricMagneticValve、PipeLine And Connectorcomposition。The pressure inside the pressurized enclosure is controlled by the precision pressure-reducing valve, throttle valve, and inlet and exhaust solenoid valves in linkage, keeping the pressure in each pressurized enclosure stable between 100Pa and 300Pa.。
The protective gas is transmitted through valves, piping, etc., filtered and pressure-reduced to become pure micro-pressure gas that enters the positive-pressure enclosure. After 30 minutes of purging, the content of potentially explosive gas inside the enclosure is diluted to a safe range, and positive pressure is continuously maintained, making the interior of the positive-pressure enclosure a safe location for electrical installation.。
The flameproof control box is responsible for providing power to the coil of the main contactor inside the positive-pressure enclosure and for detecting the positive pressure value within the enclosure, achieving low-pressure and high-pressure alarms, automatic gas intake at low pressure, and automatic gas release at high pressure. When the positive-pressure enclosure has been purged for 30 minutes and the internal pressure is greater than 50Pa, the main contactor inside the electrical cabinet can be energized and supply power to the control relays of other non-essential electrical equipment in the driller's cabin. When the pressure drops below 50Pa, the system automatically alarms and opens the intake solenoid valve to admit gas; when the pressure rises above 200Pa, the exhaust solenoid valve opens to release gas.
Installationlocation
ElectricalCabinetinNextColumnEnvironmental ConditionsAbilitynormalIndustryOperating:
AltitudeInvincibleexceed2000m；
Ambient Temperature:-20℃～+50℃。
AerospaceStationRelative Humidity:MosthumidMonth份，MonthStandardAllMostHighRelative HumidityInvincibleGreaterIn90%；
haveⅡA、ⅡBLevelT1~T4UnitExplosive Gas（ Or LiquidStructure、EvaporateSoda）的Zone 2EnvironmentIn；
nonIntenseIntenseVibrationInteraction And impact的InvincibleAspect。
ElectricalCabinetShouldByWithqualification的InstallationTechnical PersonnelAccordingFoundationManual的Installation InstructionsTrulyEnsureInstallation
InstallationFrontShouldInspectpower supplyVoltage， And Environmental ConditionsIsno And NameplateSupremerequirementsOneCausing。
The installation location of the electrical cabinet should avoid places directly exposed to moisture, seawater, wind, rain, sunlight, etc. Measures should be taken when necessary.。
UsesafetyRequiredWell-known
UseFoundationElectricalCabinetPositionFront，PleaseCertificationTrulyReadFoundationManual。
The flameproof control box of this explosion-proof control cabinet is electrically interlocked with the positive-pressure enclosure power supply. Only after the positive-pressure enclosure has been purged for 30 minutes and positive pressure has been established will the main power contactor coil be energized, allowing power to be supplied inside the positive-pressure enclosure.。
It is strictly forbidden to open the cover of the explosion-proof control cabinet while energized; if opening for inspection or maintenance is necessary, the upstream power supply should be cut off first.。
The gas source for the positive-pressure control system must be purified compressed air or other non-combustible gas (nitrogen N2).。
If explosion-proof components equipped with the electrical cabinet are damaged, contact the seller for repair or purchase.。
Do not arbitrarily replace, modify, or adjust components and structures that affect explosion-proof performance.。
Do not arbitrarily install components on the positive-pressure enclosure shell.。
When the positive pressure value drops below 50Pa and a low-pressure alarm is triggered, the staff must immediately take measures to raise the positive pressure value to 50Pa, or should cut off the power for inspection. Only after the fault is eliminated and the positive-pressure system returns to normal can the equipment be restarted.。
