Explosion Proof Valves are used in Hazardous Locations where there is a risk of explosion or fire. These valves have thick metal components that surround the coil which will contain an explosion and prevent the ignition of flammable gas or vapors in the surrounding environment.
To efficiently simulate the dynamics of explosion-proof safety valves, 3D CFD modeling is performed. However, this method requires large mesh grids and computing resources. To overcome this limitation, model simplifications such as equivalent volume and equivalent porous methods are investigated.
Safety Features
Explosion proof electric actuators can be used to control rotary valves and are ideal for use in hazardous environments. They are designed to prevent accidental contact with live parts, and feature hard aluminum alloy, anodized or polyester powder coating, and high strength corrosion-resistance.
There are various explosion proof solenoid valves available that meet different standards, including CE (European Union), ATEX (ATmospheres EXplosibles) and CSA (Canadian Standards Association). They are used for fluid control in hazardous applications.
Explosion isolation valves protect filters, mixers, cyclones, mills and central vacuum cleaning systems from an explosion spreading to other plant equipment. They are installed in ducts and can be activated by an explosion signal from a decompression panel burst sensor or a pressure sensor mounted on a duct wall. They can also be operated manually. They are usually installed in Class I, Div. 1, Groups A, B, C and D and Class II, Div. 1, Groups E, F and ATEX Zone 1 or 2 locations.
Operation
Explosion Proof Valves are a special solenoid valve series designed to transmit flammable and explosive media or specially used in explosive hazardous places. Their coil shell not only has the flameproof effect of bearing gas explosion pressure but also has a blocking effect on energy transfer of gas explosion, which makes them have higher safety performance than ordinary solenoid valves.
They are primarily used for the control of movement direction of hydraulic cylinders or motors, and they can be either proportional or direct-acting. They comply with ATEX 94/9/EC standards and can be used in potentially explosive atmospheres that fall within the ATEX II 2GD for gas or dust classification. They have a Zinc-Nickel surface treatment, and they can be connected to a current-controlled power supply.
The explosion-proof cargo lift is a kind of mechanical equipment that can quickly load and unload goods, which is mainly used in factory assembly lines, warehouses, cargo stores, parking lots, docks, construction, etc. The explosion-proof elevator is equipped with a hydraulic explosion-proof valve, which plays an important role in the normal rising and falling process of the freight lift.
Maintenance
Explosion proof solenoid valves are used in hazardous locations to control the flow of flammable gases, vapors and liquids. They utilize thick metal components to prevent an explosion from occurring when a coil is de-energized. To ensure that these safety devices are working properly, it is recommended to inspect them regularly.
Check for the direction of the medium flow (there is an arrow impregnated on the valve body). Also, check for proper connection of the power source, ensuring that the voltage of the power supply meets the specifications (+/- 10%) labeled on the solenoid coil.
External contamination such as sediment or dust can limit the armature’s motion, causing it to overheat. Corrosion of metallic parts, or contaminated diaphragms and seals can also result in valve malfunction. To avoid these issues, an upstream filter can be installed in the pipe.
Design
Explosion Proof Valves are used in hazardous locations where fire or explosion hazards may exist due to the presence of flammable gases, vapors, liquids, combustible dust, or ignitable fibers. They use thick metal components to contain an explosive event. This protects the coil from resulting damage, and allows the escaping gas to cool below the ignition temperature of the surrounding atmosphere.
To understand the dynamic behavior of this type of valve, a 3D CFD simulation is performed and analyzed. Various models are tested, with the ability of prediction in fluid force as an evaluation criterion. The comparison of 2D and 3D model performance shows that the shear stress transport (SST) k-omega model is superior for predicting fluid disc force. Moreover, the impact of mesh grid size and timestep on the solution quality is investigated. In addition, a 2D simplification method is also evaluated. Different simplification models have differing performances in predicting the blocking effect of flame-retardant sheets.
