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Mechanical Explosion Isolation

The explosion isolation Valve VEX stops flame’s propagation in ducts, protecting the rest of the equipment within the installation.

The explosion isolation Valve “VEX” by Adix is an economical and efficient solution to protect against the propagation of explosions in ducts.

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What is Explosion Isolation?

An isolation system works to avoid the propagation of deflagration during its processes: thanks to this, the effects of the explosion remain limited in the part of the equipment where the deflagration began.

Numerous investigations and trials have demonstrated that the explosions spread through tubes, and in all processes exist ducts that link together equipment, or even, the ducts can lead to a personnel area.

On the other hand, the explosions tend to be more severe in tubes than in closed receptacles.

After the flame combustion begins, it propagates throughout the combustible product that is not yet burned, also crosscurrent to the normal flow of processes, generating a pressure wave ahead of the combustible product in flames, and that has a superior velocity to that of the flame but inferior to the velocity of sound, which means that it produces deflagration.

Normally, factors such as turbulence and the increase of the surface of the flame accelerate the flame front, and if it is able to continue and there is sufficient air and combustible substances, it will exceed the speed of sound resulting in detonation, that should in every way be avoided due to its destructive effects.

The isolation systems are based on avoiding the spread of the flames, and there are various techniques that exist to achieve this objective:

Chemical isolation systems

They are designed to act after the start of an explosion has been detected, by unloading an extinguishing agent, that way avoiding the propagation of flames.

These systems act in three stages:

Detection, which is achieved by means of components that are activated by static pressure, dynamic pressure or light (UV/IR).

Commencement, as a result of the detection, a signal is sent to the electronic control system indicating that the start of an explosion has been detected and therefore the given system starts the sequence of valve opening that free the extinguishing agent, which is contained within a pressurized bottle.

The extinguishing agent is discharged, by action of a gas pressurized impulse over the actuator piston of the discharge valve.

The suppressing agents avoid the propagation of the flame front through the following mechanisms:

Absorbing the heat energy produced by the flame, lowering the temperature of the flame below the point of self-combustion. Inhibiting the combustion reaction by neutralizing unburned product.

Lowering the concentration to a value in which combustion cannot exist. In order to achieve this effective isolation of the deflagration, the discharge of the sufficient amount of extinguishing agent must begin milliseconds after the detection.

Passive mechanical systems

The Anti-explosion Valves cease the propagation of the explosion in ducts, protecting the equipment in the installation.

Throughout the operation of the installation, the flow goes through the valve clapper maintained in the open position. When the installation is stopped, the in absence of flow, the clapper closes by its own weight.

In the case of explosion in installation equipment where the valve is installed (for example in the Filter), an expansion of gas is produced, whose excess pressure closes the clapper, isolating and protecting the rest of the installation equipment in this way. The Adix clapper’s anti-return valve is an economical solution to help protect against the propagation of explosions in tubes.

Active mechanical systems

Are different from the chemical systems in that the progress of the flames is ceased through the closing of mechanical isolations valves.

Description of passive isolations valves VEX

The detectors transmit a signal to the control unit that at the same time activates the extinguishing bottles. The bottles are equipped with fast opening valves that immediately release the extinguishing agent creating a very effective barrier:

  • High velocity system reaction from detection to extinction
  • High system reliability
  • Independent storage for detector data
  • Personalization of Detector, control units and container unit
  • High quality components
  • Personalization according to the client’s requirements
  • Suitable for interior or exterior use

Description of passive isolations valves VEX

  • For tube sizes starting at DN 100
  • Optional position indicator
  • Does not require electric energy or system activation
  • Variable installation distance
  • Simple installation and maintenance, low cost maintenance

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