A desiccator is used to organize and store substances that are sensitive to humidity. A desiccator cabinet has a dust-free and clean storage environment, which is needed for sensitive substances or compounds that are stored and/or used in a laboratory.
There are usually 5 types of desiccators and they are made for different purposes and requirements. There may be models in the market that are modifications on top of these base models.
This is a desiccant chamber where a desiccant, like silica gel beads, is used to absorb moisture from within the cabinet. Desiccants come in reusable cartridges. The plus point about this type of desiccator is that it is economical, while desiccants can be regenerated by using an oven or microwave. Regeneration means the desiccant dries up and can absorb moisture again. However, this type of desiccator needs to be monitored and the desiccant has to be replaced timely, to maintain the dry environment inside.
Gas Purge Desiccator
A constant flow of inert gas, like compressed dry air or dry nitrogen, is used to maintain low levels of humidity. A flow-meter manages the flow. This kind of cabinet can achieve lower humidity levels faster than a desiccant based equipment. The cabinets are also generally larger. The RH% can go as low as 0%. If the flow of gas is increased, it can get dry inside quickly. There isn’t much manual intervention required, although monitoring is manually done. Oxygen deficiency is a risk if nitrogen is released and proper ventilation is required.
This device has a fan or an electrical heater, for regenerating the desiccant, to prevent moisture from saturating within. It is automatic and manual monitoring isn’t required. It uses silica gel, so the dehumanization process is slow.
Automated Gas Purge Desiccator
This is the same as the one as a Gas Purge Desiccator, except that it is automated. There is a purge system that is controlled automatically, and which monitors the RH% and adjusts the gas flow.
A vacuum pump is used to create a dry environment. Vacuum desiccators come in form of jars and cabinets. They are ideal for extremely dry environments with minimum levels of oxygen. However, these desiccators have limited capacity for shelving and storage.
Each of the desiccator s given above have their own pros and cons. Price, operation, storage, monitoring, size and speed are some of the features that have been considered in their discussion. If you can do with a basic Stainless Steel desiccator that is also within a budget, then a regular desiccator can do. The operation of the desiccators, meaning the way they function, involves a desiccant, inert gases or vacuum. A desiccant based device needs constant monitoring, while the desiccant has to be replaced periodically, or it can be regenerated. Vacuum and inert gases may not have to be monitored while being used to purge the container, but the gas cannot be regenerated. The cost involving these elements will also determine your choice. Jar-shaped desiccators have lesser storage space but also can be easily stored in a tiny amount of space.
Each desiccator type is listed out and you can make a choice based on what your requirements are.