Filtration of dirty air at every step of your process

Though inputs and outputs may look similar, each foundry's process can vary greatly from other foundries across the industry. For example, the die casting process is significantly different from that of sand casting or forging.

Regardless of the method, processing metal creates dust, smoke, and fumes that are harmful to employ health, operational equipment, and the quality of finished products.

Keller's Clean Casting brings air filtration to every step of the casting / metal forming process.  With increasing focus on improving air quality standards and the explosive properties of light alloy metals, it has never been more important to ensure the solution and process match. 

 

How can Keller bring value to your operations?

By providing products and expertise to address concerns for each process phase: from melting to forming to finishing. 

 

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Common Casting Challenges:

Gaseous matter might be adhesive or odorous during some casting processes. These sticky fumes quickly clog the pores of the filter element causing premature failure of the dust collector.  Without proper filtration material and capturing, this type of fume can cause problems in the dust collection process (particularly the ductwork), leaving employees and equipment exposed to harmful particulates and operational accidents.

Potential Dust Collector Remedies:

  1. Automatic Dosing Supply: The automatic online dosing of an inert powder (limestone or clay) into the dust collector dirty air plenum.  This powder coats the filter elements and acts as a sacrificial barrier by absorbing the adhesive and humid particulates and preventing from penetrating the filter pores 
  2. KLR Filter Plate: Keller’s KLR-bran filter plate with PTFE membrane ensures that the combination of pre-coating powder and process emissions can easily disperse off the filter plate by automatic self-cleaning compressed air pulses.  The wide pleats of the KLR-bran filter plate, in comparison to the deep pleats of traditional round cartridges, provide continuously active filter surface area without trapping the particulates
  3. Bin Dosing: When the KLR-bran filter plates are cleaned off additive agent is dosed from the disposal bucket providing an additional protective layer on the filter surface until new material is fed by the automatic dosing unit

This combination not only provides long filter life with constant 24-hour airflow but has additional ancillary benefits of reduced fire risk due to the addition of inert powder into the mixture of dirty air emissions and potential smell reduction (absorption of hydrocarbons).

Keller also provides wet scrubbers and mist collectors with pre-spraying processes that can help address issues raised by gaseous fumes.

Fires in dust collector systems rely on two factors: fire load (the fuel for the fire) and ignition source (the source for the fire).

The fire load can exist due to one of more of the following fuels:

  1. Filter Elements: Filter elements consist of natural, synthetic or organic material (paper, cotton, needle felt and plastic granulate) and are therefore classified as combustible. Basically, a fire risk exists. For example, the thermal value for polyester is 6.3 kWh/kg.
  2. Secondary Sources: Secondary flammable sources such as oily air from sheet metal sheets, aerosols, or other foreign matter that can be easily ignited
  3. Dust: The fire risk increases by the dust accumulation in the filter if the material separated is also flammable

The source of the fire can come from internal or external sources:

1. Internal Ignition Source (Inside the Dust Collector)

  • Hot Surfaces
  • Static Electricity

2. External Ignition Source

  • Operational ignition sources (ie. sparks)
  • Exothermic reactions including spontaneous ignition of dusts 

Some potential solutions to reduce the risk for fires include:

  • Spark Preseparation: The threat of introducing ignition source from the operation is reduced by using a spark preseparator to divert and minimize their energy.  However, no spark preseparator is 100% effective and a residual risk remains.  
  • Solid Matter Inertization: Solid matter inertization offers the possibility to generate a non-combustible dust mixture from combustible dust by adding limestone powder via a dosing device.  This reduces the threat of combustion and provides an auxiliary protective layer on the filter elements to extend filter life.
  • Monitoring Fire Detection: Sensors to monitor for different fire sensors including sparks entering (infrared spark detector) and smoldering fires (temperature sensors in hopper and clean air side).  The detection can be used to either alert the operator of the fire hazard or initiate automatic fire suppression system.
  • Automatic Fire Suppression: After alert of a fire event an automatic fire suppression system can be initiated with a return valve preventing the flame from escaping and a shut-off valve preventing the exhaust of the suppression agent.  An extinguishing agent such as Argon is dispensed into the isolated filter housing to remove the fire risk.

The manner of capturing dust and fumes depends on the production process in use. Optimally, fumes are captured at the source.

However, for some foundry processes, the parts being handled are too large or unconventionally shaped to allow for source capturing while still allowing an employee to work efficiently. In these situations, custom capturing elements or an ambient collection of fumes is needed.


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