Many industries in which combustible dusts or gases are handled risk the devastating effects of an explosion. The amount of heat liberated during an explosion creates extremely high pressures which can result in damaged process equipment, loss of production and serious injury to personnel. Leading insurance firms estimate the average direct costs of an explosion in the hundreds of thousands of dollars, with many unprotected explosions leveling plants, or even closing businesses.
Explosion Suppression systems are designed to detect and chemically suppress an explosion in its earliest stages before it can cause a disaster or become catastrophic. While unsuppressed explosion pressures can reach dangerous levels in less than 50 milliseconds, this unique technology can detect and respond in less than 30 millisecond – averting a catastrophe. Patented container and nozzle designs minimise flow restrictions, helping extinguish the explosion faster and minimising pressure build-up inside the process equipment. The suppression container has no moving parts or wear points, increasing the reliability of the system.
The GCA consists of a 17-4 PH series stainless steel body containing two sets of bridge wires. This device is designed to operate by electrical input from a Fike system controller. Operation of the GCA occurs when the electric current is sent through the bridge wires causing an exothermic chemical reaction. This generates the necessary pressure to open the rupture disc and discharge the suppressant agent or pneumatically drive the gate closed on the isolation valves.
High Rate Discharge (HRD) nozzle assemblies are mounted between the explosion suppression container and vessel wall. Nozzle assemblies are available in spreader, telescopic, and no-nozzle configurations. To equip an HRD suppression container for use, it is necessary to order a nozzle assembly and its compatible nozzle cover and bolting pad. Each part is sold separately to maximize design flexibility.
Dispersion nozzles are mounted directly to the agent storage container. These patented “Zero Restriction” nozzles do not add additional flow restrictions. In fact, the total area of the dispersion orifices is twice that of the nozzle inlet. In addition to the standard nozzle, Fike offers a flush-mount, telescoping nozzle for hygienic or abrasive applications.
Fike suppressant containers provide optimum performance in delivering chemical suppressant agent in suppression and isolation applications. The patented high-rate-discharge (HRD) standard-rate-discharge (SRD) suppressant containers are specifically designed to reduce the time required to inject and disperse the agent, suppressing the explosion. HRD and SRD containers can be used in both suppression and chemical isolation applications.
Fike’s High Rate Discharge (HRD) Mechanical Lockout Assembly provides a means for the user to physically prevent an accidental discharge of the HRD suppression container into the process vessel and to electrically prevent the unintentional arming of the suppression system by the Fike Explosion Protection Controller (EPC).
The Fike Prepackaged SBC Explosion Suppressant eliminates the hassles of transporting and weighing suppressant containers after activation. The time required for moving the suppressant containers from their installed location to a scale, weighing the container and powder, and then moving the container back to its installation location are now gone.
Fike Ball Valve Lockout Assemblies provide a means to physically prevent an accidental discharge of an explosion suppression or isolation container into the process vessel. Each Ball Valve is equipped with electrical contact switches that prevent the unintentional arming of the explosion protection system controller (EPC).
Attaching a Standard Rate Discharge (SRD) explosion protection container to a duct requires an SRD nozzle assembly. SRD containers are connected to the nozzle assembly by a length of either rigid pipe or a flex hose, based on application requirements.
In the production of powdered food or pharmaceutical products, one process step involves drying the product. This is commonly done by a fluid bed or spray dryer. Inherent to this process is the requirement to suspend the powder in air. The suspended powder may create a dangerous potential for an explosion and in cases where a flammable solvent or gas is present with the powder (hybrid mixture) this explosion potential is magnified.
Dust collection involves the removal, or collection, of solid particles from a flowing air stream, for the purpose of eliminating nuisance dust, the safety and health considerations of employees, product quality improvements, and the collection of powdered products.
The powders produced from liquid feedstocks are suspended in the spray dryer at elevated temperatures presenting possible fire and explosion hazards. in the production of food or pharmaceutical products, there could also be residue solvents (hybrid mixtures), that increase explosion hazards.
Bucket elevators are among the most common conveyors used for making vertical lifts of bulk materials. The materials being conveyed can vary over a wide range of sizes, from powders to pellets. Most of these bulk materials inherently produce dusty conditions within the bucket elevators, creating explosion hazards.
Raw coal is fed into the coal inlet, dried and ground to a fine dust on the grinding table. Hot air (inert gas) is used to pneumatically carry the coal dust upward through the classifier and into the transport pipe.
A dust collector (bag house) is typically a low strength enclosure that separates dust from a gas stream by passing the gas through a media filter. The dust is collected on either the inside or the outside of the filter. A pulse of air or mechanical vibration removes the layer of dust from the filter. This type of filter is typically efficient when particle sizes are in the 0.01 to 20 micron range.
Dust laden gas enters the chamber from a tangential direction at the outer wall of the device, forming a vortex as it swirls within the chamber. The larger particulates, because of their greater inertial, move outward and are forced against the chamber wall. Slowed by friction with the wall surface, they then slide down the wall into a conical dust hopper at the bottom of the cyclone. The cleaned air swirls upward in a narrower spiral through an inner cylinder and emerges from an outlet at the top. Accumulated particulate dust is deposited into a hopper, dust bin or screw conveyor at the base of the collector. v
In an electrostatic precipitator, particles suspended in the air stream are given an electric charge as they enter the unit and are then removed by the influence of an electric field. A high DC voltage (as much as 100,000 volts) is applied to the discharge electrodes to charge the particles, which then are attracted to oppositely charged collection electrodes, on which they become trapped.
In an electrostatic precipitator, particles suspended in the air stream are given an electric charge as they enter the unit and are then removed by the influence of an electric field. A high DC voltage (as much as 100,000 volts) is applied to the discharge electrodes to charge the particles, which then are attracted to oppositely charged collection electrodes, on which they become trapped.EAP 10
Transport pipes and ducts are enclosures that move coal dust from one piece of equipment to another, or that brings heated gases into the equipment for process operation. These enclosures can range from lightweight sheet metal to heavy wall pipe. They can be round with diameters up to approximately 5 feet, or rectangular with cross sections up to approximately 2’x3’
1999, Coal Supplied 56% of the nations electricity.
Cement manufacturing is one of the largest mineral commodity industries in the United States, with an estimated production capacity of greater than 73 million metric tons annually.
Most manufacturing processes require the removal or collection of dust particles, whether that is eliminating nuisance dust or collecting powdered products. After removal or collection of dust particles, the solid particles typically must be separated from the flowing air stream. One method of separating the solid particles involves using a cycling and dust filter (see figure on page 3). Heavier dust particles are first separated from the air stream into the cyclone through centrifugal forces, then the smallest particles are separated from the air into the dust filter
At an elevator facility, a truck unloading system is used to move grain from the truck into storage silos. While conveying grain throughout the system, fine dust will become airborne creating a risk for dust explosion in practically every process section: (see Figure on page 3 from left to the right) truck unloading hopper, bucket elevator, silo and dust aspiration/filter system.
The pulverisation of coal to improve burning efficiency and maximize energy output is a method that has been used for more than 75 years.Pulverised coal processing and storage systems are typically found in power generation, steel and iron manufacturing, cogeneration, cement drying, and other industries that employ injection furnaces.
The nature and operation of dust collection equipment present possible fire and explosion hazards, due to the greater concentration of small particle material. Dust collectors experience more explosions than any other process vessel types.
A cement kiln is the world’s largest moving manufacturing machine. Cement kilns are cylindrical ovens, some as long as 1000 feet and as much as 24 feet in diameter. They rotate one to three times every minute. The kilns are mounted at a slight incline. The inside is lined with fire resistant brick. Powdered coal, oil, gas, liquid waste-derived fuel, and solid waste fuel are used to fuel the kiln. Raw material enters the kiln and is heated to over 2700°F. The material leaving the kiln is called clinker.
This process includes a hopper for manually feeding product into a powder handling plant (see figure on page 2). Filling of product hoppers can cause dust particles to become agitated and suspended in air. This dust laden atmosphere can then support a deflagration if an ignition is introduced. A dust collector is installed onto the hopper to pull vacuum, which in effect limits the amount of dust that will become airborne both inside and outside the hopper when feeding the product.
Fike introduces the use of bus network technology to the explosion protection industry. Fike’s explosion protection control system uses bus network technology to exchange information between its components, and to “connect” protection controllers to ‘enlarge’ the protected area if required.
Single detection is sufficient for most applications, however paired detection is an option dependent on customer preference (some users have a tradition of using 2 detectors in tandem at each detection point (location) or 2 detectors may be required to achieve a stable working system for specific high demanding applications (see ‘paired’ below).
Explosion Protection Controller (EPC) The cornerstone of the system is the Explosion Protection Controller (EPC). The EPC is an addressable panel that has the ability to retain event history for enhanced system diagnostics. The EPC should be installed as close as practically possible to the protected environment, thereby minimizing field wiring.
EC-Type Examination Certificate
Canadian Registration for HRD Containers
DWG. E30-016-02-XX ET AL, EIV Valves sizes 2" through 8"