The refrigeration system of these test chambers are either conventional single stage systems or two stage cascade systems. All of the chambers are designed to satisfy both military and commercial requirements standard to industries performing low temperature test programs.

The single stage unit consists of a single compressor and single refrigerant. Associated uses a single stage system on all of our standard and custom designed chambers requiring a low temperature limit of -40° Fahrenheit/-40°Celsius.

All chambers, including CO₂/LN₂ Chambers, incorporate non-magnetic welded type 304 stainless steel inner chambers. The exterior cabinet is fabricated of reinforced cold rolled steel with fully welded construction. A textured enamel finish offers a pleasing laboratory appearance.

Doors on most chambers are combination hinged and removable, allowing for modifications and easy access to the test area. All doors are gasketed with silicone offering the expanded temperature characteristics of these materials. Latches all have quick action cam mechanism for positive closure.

The insulation used for thermal integrity in the walls and doors of all our chambers is a high density low "K" factor, non-settling Fiberglass. This insulation optimizes the efficiency of the equipment and minimizes operating costs.

Forced air circulation systems are standard in these chambers to maintain precise temperatures. The fan is powered by a direct drive, heavy-duty electric motor, externally mounted with an integral stainless steel shaft.

The heating systems in our chambers are open wire nichrome resistance elements which combine maximum heat transfer with rapid response time and long operating life. The heaters are located in a plenum, such that, test specimens are not subject to direct radiation.

All Associated chambers feature, as a standard, a high temperature fail-safe control. This fail-safe provides added insurance against damage due to abnormal temperature extremes. In addition, chambers are fitted with fusible thermal links to guard against temperatures exceeding the upper design limits of the equipment.

Temperature/Humidity Chambers are offered by Associated to program controlled conditions of combined temperatures and relative humidity. The HD-500 series utilizes a single stage mechanical refrigeration system capable of producing dry bulb temperatures as low as -40°F (-40°C).

The HD-200 series extend the low temperature capability of the equipment to a dry bulb temperature of -100°F (-73°C).

The high temperature systems in these series consist of stainless steel finned heaters which are non-corrosive and are baffled to eliminate direct radiation to the test pieces at temperatures up to +350°F (+177°C). Special conditions of temperature and humidity may require consultation with Associated's special design engineering services.

These chambers have hermetically sealed liners, fabricated of heliarc welded stainless steel. All components in these chambers have been selected to offer maximum resistance to the corrosive effects of moisture combined with extreme conditions.

Salt Spray/Fog Chambers are designed for corrosive atmosphere testing. Test specimens are hung or supported within the test area by Lucite® rods, are subjected to corrosion by means of a salt residue being deposited on them or the generating of a salt fog atmosphere. Direct visual observation of the items being tested is available at all times.

These test chambers are constructed of non-corrosive materials. Test chamber and saturation tower feature transparent lucite with a stainless steel base.

The need for true Thermal Shock testing has been expanding rapidly due, in part, to the enormous competitive pressures existent, particularly within the general electronics industry. The utilization of these latest technological advances for applications in medicine, computer technology, space exploration, defense research, even the automotive industry, are testimony to the increased necessity to produce products with the highest possible reliability quotient.

Clearly, thermal shock testing does provide the means to achieve this reliability objective. Currently, more and more manufacturers are turning to full temperature cycling or thermal shock testing of their electronic components, semiconductors, computers, instruments and peripheral electronic equipment.

Thermal Shock Chambers allow the test specimen to be automatically and repeatedly transferred from a hot environment to a cold environment or the reverse of this temperature sequence. This process is defined as true thermal shock, as opposed to thermal cycling, wherein the specimen is introduced into the chamber and the chamber temperature is then cycled; a process which may require two hours to ramp up or down and attain a similar 265°C temperature variation.

Associated Environmental Systems offers both a Two Station and Three Station Thermal Shock Chamber. The upper compartment provides the heated environment while the lower compartment provides the cold environment in both the two and three station chambers. The three station chamber also contains a middle compartment between the hot and cold compartments. This middle compartment is exposed to room ambient (ambient dwell) and is enclosed with expanded metal. Each type chamber contains a specimen holding basket (transport carriage), which is pneumatically operated from a compressed air source.

In tight tolerance environmental rooms, air must be evenly distributed and constantly recirculated at a higher than normal rate in order to maintain uniformity and accuracy. A portion of one wall of the room is devoted to a conditioning plenum. Air is drawn into the lower part of the plenum through a set of cleanable filters, across an evaporator coil and vertically across electric heaters. The air then enters centrifugal fans and is discharged into a perforated ceiling plenum. The air flows vertically downward in the room and is returned horizontally through the cleanable filters to the wall plenum.

Mechanical refrigeration systems are designed and furnished to operate continuously when in the cooling mode. Automatic capacity reduction is achieved by means of a hot gas by-pass system when the room is at the set point temperature. The standard compressor-condensing units are air cooled and up to 5 HP units can be mounted on the roof of the room. Larger units are mounted on the floor adjacent to the room. All units incorporate the highest quality components such as, liquid line solenoids, liquid sight glass, driers, strainers and TX valves. Units that operate at -35°C and above are single stage units, below -35°C the units are two stage.

All chambers incorporate non-magnetic welded type 304 stainless steel inner chambers. The exterior cabinet is fabricated of reinforced cold rolled steel with fully welded construction. A textured enamel finish offers a pleasing laboratory-designed appearance.

Doors on most chambers are combination hinged and removable, allowing for modifications and easy access to the test area. All doors are gasketed with silicone offering the expanded temperature characteristics of these materials. Latches all have quick action cam mechanism for positive closure.

The insulation used for thermal integrity in the walls and doors of all our chambers is a high density low "K" factor, non-settling Fiberglass. This insulation optimizes the efficiency of the equipment and minimizes operating costs.

Forced air circulation systems are standard in these chambers to maintain precise temperatures. The fan is powered by a direct drive, heavy-duty electric motor, externally mounted with an integral stainless steel shaft.

The heating systems in our chambers are open wire nichrome resistance elements which combine maximum heat transfer with rapid response time and long operating life. The heaters are located in a plenum, such that, test specimens are not subject to direct radiation.

All Associated chambers feature, as a standard, a high temperature fail-safe control. This fail-safe provides added insurance against damage due to abnormal temperature extremes. In addition, chambers are fitted with fusible thermal links to guard against temperatures exceeding the upper design limits of the equipment.