Explosion-Proof Housings

For in-house correlations, the cost of electric motors should be correlated vs. horsepower with voltage, speed, and type of construction as correction factors or parameters. Correction factors for explosion proof or open drip-proof housings could he developed if most of the data is for TEFC (totally enclosed fan cooled) motors. Similarly, correction factors could be developed for 1,200 rpm and 3,600i pm with l.SOOrpm as the base. 

Seals are required at entries by conduit or cable to explosion-proof enclosures containing arcing or high-temperature devices in Division 1 and Division 2 locations. It is not required to seal IM in. or smaller conduits into explosion-proof enclosures in Division 1 areas housing switches, circuit breakers, fuses, relays, etc., if their current-interrupting contacts are hermetically sealed or under oil (having a 2-in. minimum immersion for power contacts and 1-in. for control contacts). 

It is therefore more cost effective to use a large ultrasonic system supplying 80 kW to process liquids at a flow-rate of 10 m /h than to use 5 ultrasonic processors with a power of 16 kW each or 40 processors with a power of 2 kW each. The robustness of the transducer enables its use under heavy-duty industrial conditions. Also, the processor can be designed to be explosion-proof. Like the transducer and the flow cell, the generator is housed in two connected compact stainless steel cabinets. This makes the device self-contained, robust and easy to install. The standard footprint of a 16-kW system is just 600 mm x 1200 mm. 

The most appropriate switch for this application would be the Mercoid switch DSH-7341 -153-23E. This is the same as the Mercoid switch DS-7341-153-23E except that it comes with an explosion-proof housing. With the addition of the explosion-proof housing, the switch costs almost twice as much. 

Relays such as those used in this particular system can be extremely dangerous because the contact points can spark and very easily ignite a fuel rich atmosphere, which will cause an explosion. Keep the controller well away from the rest of the system, or house it in a pressurized unit with alarm or alert shutdown controls, or in a flanged explosion-proof enclosure. 

Houses located in hazardous areas should comply with the electrical reg lations in force. In some cases, the whole house must be pressurized by using a source of fresh air in non-hazardous areas and an air-sensitive switch to automatically turn off the electrical power if the aeration system should fail. Even if the air is efficiently renewed, explosion-proof switches should be used for aii electrical apparatus. 

If an area is always hazardous due to the flammability of the chemicals in its processes, all the electrical equipment in that area must be enclosed in explosion-proof housings. Equipment which sparks or arcs during normal operation will sooner or later contact a flammable gas or vapor and the result will be a fire or explosion. To prevent this, electrical equipment which sparks or arcs during normal operation must always be explosion-proof even when used in an area which is only infrequently hazardous. 

Explosion-proof electrical equipment (see Figure 7-5) presents no explosion hazard if properly installed and maintained. Such equipment is designed to withstand the pressure created by an internal explosion and to cool hot gases below ignition temperature before they reach the outside of the explosion-proof housing. This cooling is accomplished by routing... 

All fans used on or near the tape casting machine should be explosion-proof if volatile, flammable solvents are being used in the process. On many of the laboratory-scale machines this problem is eliminated by the use of "house air" provided by a remote compressor. On these systems, the airflow through the machine is controlled by the use of flow meters and the cross-sectional geometry of the drying chamber itself. 

There are several strategies for enclosure housing used in classified environments. The two most applicable to Raman analyzers are explosion-proof and purged. 

Many mining applications require electrical components to be housed inside explosion-proof enclosures. An explosion-proof enclosure is an enclosure that will withstand internal explosions of methane-air mixtures without causing damage or excessive distortion to the enclosure walls or cover. In addition, flames from internal explosions must not propagate to outside the enclosure. 

Shack No. 6 Lead Burners Shop Photo Chemical Laboratory Shack No. 7 Shack No. 8 Shack No. 9 Smoke House Explosive Warehouse Concrete Gun Pit Fragmentation Box Armor Plate Bomb Proof Lead Furnace House Mustard Laundry... 

Explosive Warehouse Concrete Gun Pit Fragmentation Box Armor Plate Bomb Proof Lead Furnace House Mustard Laundry... 

For operations the housing has to be equipped with leak-proof sliding windows. To avoid the accumulation of harmful and explosive gases, suction systems are installed in the housing from where CS2 is purged to a recovery facility. 

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