Desiccators

The ratio of the mass of water vapor in a sample of air to the mass of air of the sample.

The pressure above the absolute zero value of pressure that is theoretically obtained in empty space. (Example: The absolute pressure at sea level is 14.7 psia.)

The penetration of a substance into the inner structure of a solid or liquid where it is held in place by surface tension effects and is readily displaced.

The surface retention of solid, liquid or gas molecules, atoms or ions by a solid or liquid. The adsorbed material is held in place by Van der Waals and other weak inter-molecular forces and is not readily displaced.

Height, measured as distance along the extended earth’s radius above a given datum, such as average sea level.

A unit of length, 10-8 cm (10-10 meter). Used to define pore size in molecular sieves.

Motion of an aircraft in which the path is inclined upward with respect to the horizontal.

A unit of pressure equal to the pressure exerted by a column of air one inch square and extending from sea level to infinity. 1 atmosphere = 14.7 psi.

Movement of gas, vapors or air in and out of an enclosure as a result of expansions and contractions induced by temperature or pressure change (such as altitude change).

The process by which vapor becomes a liquid and energy is released.

Motion of an aircraft in which the path is inclined downward with respect to the horizontal.

The temperature at which air becomes saturated when cooled without addition of moisture or change of pressure; any further cooling causes condensation.

Pertaining to meteorological actions which are completed within 24 hours and which recur every 24 hours.

An ordinary thermometer, especially one with an un-moistened bulb; not dependent upon atmospheric humidity.

Cushioning material in a container to protect shipped goods from damage.

Condition in which no change occurs in the state of a system as long as its surroundings are unaltered.

A phase of matter in which the substance expands readily to fill any containing vessel; characterized by relatively low density.

A unit of mass equal to 1/7,000 of a pound, or to 6.47989 x 10-5 kilogram (kg).

The unit of mass in the centimeter-gram-second system of units, equal to 0.001 kg.

Water, in any phase, solid (ice), liquid (water), or gas (water vapor).

Having an affinity for, attracting, adsorbing or absorbing water.

Lacking an affinity for, repelling, or failing to adsorb or absorb water.

Atmospheric water vapor content.

Readily absorbs or adsorbs moisture and retains it.

Undesired and gradual escape or entry of a quantity, such as air or water vapor from an enclosure.

A unit of measure of length or distance equal to 1 x 10-6 meters, or 0.00003937 inches.

Water that is dispersed through a gas or liquid in the form of water vapor or small droplets, dispersed through a solid or condensed on the surface of a solid.

A type of stress which is exerted uniformly in all directions; its measure is the force exerted per unit area.

A graph, each point of which represents a specific condition of a gas-vapor system (such as air and water vapor) with regard to temperature (horizontal scale) and absolute humidity (vertical scale); other characteristics of the system, such as relative humidity, wet-bulb or dew point temperature, specific volume and enthalpy, are indicated by lines on the chart.

The act or process of cleaning and purifying by replacing the current contents with a cleaner or purer medium.

The restoring (through the application of heat or other processes) of the adsorption capacity of a desiccant.

The ratio of the actual water vapor pressure of the air-water vapor mixture to the saturation water vapor pressure, stated as a percent (dimensionless) and varies based on temperature.

The point where no more of a substance can be absorbed, adsorbed, dissolved or retained. When referred to desiccant, saturation occurs when the desiccant material will no longer take on moisture for the condition it is exposed to. For water vapor in air, when saturation occurs, liquid water precipitates (or rains) out of the air-water vapor mixture.

A measure of the internal energy of a substance, usually referred to as the degree of hotness or coldness as measured on a specific scale.

Desiccants are usually sold by performance (rate, capacity), not by weight. A standard performance definition is the desiccant unit. One unit of desiccant is defined as having an adsorption capacity of 6 grams of water at 77°F (25°C) and 40% RH. For instance, a unit of silica gel weighs 26 grams, a unit of molecular sieve weighs 32 grams and a unit of clay weighs 33 grams.

A space in which the pressure is far below normal atmospheric pressure.

The partial pressure of water vapor in the atmosphere

Water in the form of a gas, especially when below the boiling point and diffused.

The rate that water permeates through the wall or barrier of an enclosure, usually given in g/(m2 x day)or g/(in2 x day).

A thermometer having the bulb covered with a cloth, usually muslin or cambric, saturated with water in which the temperature reading is affected by the amount of humidity in the air.

The desiccator cartridge for standard 1″ breather valves can be up to about 18″ long and they will hold about 6 grams of desiccant per inch of length.

However, anything over about 6″ should be supported inside your package as the porous polyethylene tubing is not strong enough to support the cantilevered desiccant weight beyond that. Desiccant cartridges are not able to be attached to the 2″ or 4″ breather valves.

While both are packages intended to hold desiccant, a desiccant basket holds pre-packaged or bagged desiccant. It is intended to mount through a container wall and provide an easy way to replace desiccant from the outside of the container. Our desiccant baskets have long-lasting, easily removable, stainless steel covers that will accept a security wire to provide evidence of tampering and come in a variety of standard lengths. Custom lengths are available upon request.

On the other hand, desiccators are usually packed with loose, or bulk desiccants, and are located inside the container or item. They are intended to keep a specific sealed space dry. Some of our customers’ complex pieces of hardware have had as many as six desiccators, each protecting a different area of the item, as well as a desiccant basket in the container to keep the container interior and item exterior dry.

A breather desiccator is a desiccant cartridge that is mounted to a breather valve. Because the air that passes through the breather valve is forced through the desiccant in the cartridge screwed into the back of the breather valve. With a static desiccator, the air is not forced through the desiccant bed.

Yes. The desiccant cartridge reduces the flow for a given pressure drop by 67 – 75%.

The most common are molecular sieve, either Type 4A or Type 13X, or silica gel. However, any desiccant material that does not “pack” will work. When the desiccant material “packs” it can completely block the flow of air through the desiccator, rendering it non-breathable. It will still function to desiccate, but not for breathing.

AGM has made desiccators in literally hundreds of shapes and sizes ranging from the size of a small grape up to eight foot long tubes and every conceivable size and shape in between. Desiccators have been made from aluminum, stainless steel, bronze and many plastics including polystyrene, ABS, polycarbonate, acrylic, polyester, polyproplene, and combinations of plastics and metals. Manufacturing processes for desiccator components can utilize one or more of the following: milling, turning, stamping, vacuum forming, injection molding and casting.

There are two standard diameters currently available, the 2″ TA476 series and the 4″ TA486 series. Each is available in several standard lengths with custom lengths available upon request.

Yes. The 2″ diameter is available with either a TA340, TA333, or TA330 series valve as a TA476, or with the TA440 valve as the TA478 series. The 4″ diameter is available with the above choices but is also large enough to accommodate the TA770 series valve for increased breathing capacity.

The TA476/TA478 series require a 2.015″ diameter mounting hole while the TA486 series requires a 4.015″ diameter mounting hole. All necessary mounting hardware is provided.