Service life, chemical cartridges

Abstract To design an adsorption cartridge, it is necessary to be able to predict the service life as a function of several parameters. This prediction needs a model of the breakthrough curve of the toxic from the activated carbon bed. The most popular equation is the Wheeler-Jonas equation. We study the properties of this equation and show that it satisfies the constant pattern behaviour of travelling adsorption fronts. We compare this equation with other models of chemical engineering, mainly the linear driving force (LDF) approximation. It is shown that the different models lead to a different service life. And thus it is very important to choose the proper model. The LDF model has more physical significance and is recommended in combination with Dubinin-Radushkevitch (DR) isotherm even if no analytical solution exists. A numerical solution of the system equation must be used. 

Combination Type C supplied-air respirator [see below], demand type, with half facepiece, and auxiliary self-contained air supply (2) Type C supplied-air respirator [see below], demand type, with half facepiece or (3) Any chemical cartridge respirator with an organic vapor cartridge which provides a service life of at least 1 hour for concentrations of vinyl chloride up to 10 ppm. 

OSHA urges employers I to be conservative when evaluating service life testing data such as temperature, humidity, air flow through the filter, work rate and the potential interference of chemicals. The outcome of this evaluation dramatically affects the service life of APRs cartridges. 

B) Provide an organic vapor cartridge that has a service life of at least one hour when using a chemical cartridge respirator at vinyl chloride concentrations up to 10 ppm. 

---