 All Walk-In Environmental Rooms are constructed of prefabricated, modular, sandwich type panels with a metal skin inside and outside. The panels are joined together in a tongue-and groove fashion with silicon gaskets and are fastened to each other with cam speed locks. This modular construction allows for easy removal, re-location or expansion of the room as required. Panels are shipped in a knocked-down fashion for assembly at the job site.
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, dryers, strainers and TX valves. Units that operate at -35°C and above are single stage units, below -35°C the units are two stage.
Room Design
Prefabricated metal sectional panels of tongue and groove type construction. The panels are light-weight for easy handling, average weight of largest panel is 84 lbs. Door panel, door, hardware, all in one piece, slightly heavier. Each panel is 100% insulated, and incorporate alignment pins to fit together accurately. Cam actuated locks insure tight fits and accommodates constant assembly/disassembly for relocating or enlarging the room. Each panel incorporates steel straps connecting locking arms with locking pins on opposite sides of panels. The assembled room has continuous steel perimeters within the insulation to hold panels tightly in place.
Windows
Viewing windows are also available. The standard multipane window has a 14" wide by 23" high viewing area and a thermostatically controlled heater wire in its' casing to reduce condensation and frost formation on the window surface. Custom size windows are available.
Lighting
Incandescent or Fluorescent lighting is provided, it depends on the application. Generally it is recommended that incandescent be used on high temperature units operating above +110°F and low temperature units operating below 0°F. Fluorescent fixtures lose output and are hard starting at low temperatures. All fixtures are vapor proof and sealed.
 Circulation System
All rooms incorporate forced air circulation whether the system is ceiling mounted, side mounted, remote, or in our standard conditioning module. The air is recirculated utilizing external heavy duty motors of the finest quality with internal cooling fans, protectors and stainless steel shafts. Aluminum or stainless steel squirrel cage blowers circulate the air, all mixing is accomplished within a plenum external to the room working area. Various airflow patterns are offered to accommodate your product size and arrangement within the room. Horizontal, vertical or a combination of both can be offered for more even distribution of air and closer temperature control for rooms with modest live loads and airflow, and where noise is a consideration with people working within the room.
Heating
The heating system is all electric. The air is passed over fast response low watt density resistance heaters with ceramic cores. The combination of airflow, instrument response and these fast reacting heaters give very accurate and straight-line control of temperatures. Stainless Steel, completely sealed finned type heaters are incorporated in all humidity rooms. These heaters insure a long reliable life with no down time while giving very accurate air and humidity control. A separate instrument controls these heaters to provide the right amount of heat for the application.
Instrumentation
Instrumentation on standard rooms are single channel microprocessor programmers or two channel microprocessor programmers, accuracy of ±.25°C or better at the sensor. The sensors are fast acting 100 Ohm. platinum type. Various options are available. Events outputs for each step in programmer, RS-232C, RS-422A, IEEE-488 interface, cassette input / output, circular chart recorders and strip chart recorders etc.
Safety
Standard is a redundant control circuit utilizing its own controller and failsafe contactor. When this unit activates, it shuts off power to the heater circuit to prevent thermal runaway. The circulation blowers continue to run to distribute the heat within the room. This is important especially if there are products in the room generating heat. When the temperature subsides, the safety control closes again and power is again returned to the heaters. Other options available are High Temperature Safety with Complete Shut Down of Room with Manual Reset and Visual Indication, Low Temperature Safety with Complete Shut Down of Room with Manual Reset and Visual Indication, Both High and Low Temperature Safety with Manual Reset on Both and Visual Indication, Audible Alarm, and Remote Station Alarms.
 Electrical
Requirements: Standard power requirements include 208V 3PH 60HZ, 220/240V 3PH 60HZ, 460V 3PH 60HZ, 208/220V 1PH 60HZ. Other power requirements are available upon request.
Refrigeration System
The correct refrigeration package is supplied to meet the load demands of the room. All systems are supplied with the highest quality components, compressors are Copeland semihermetic or equal, controls are Penn or equal. All piping, rating, etc..., are in accordance with ASHRAE guidelines. The systems are completely assembled and tested at the factory. All components are labeled, identified, and located in easy accessible areas for maintenance. Complete piping diagrams, schematics, and charging data is provided. Systems that are available are Single Stage Mechanical and Two Stage Cascade, Air Cooled or Water Cooled Condenser.
Temperature Range
Various ranges can be provided, including fast change rates with your product load. Ranges from -73°C (-100°F) to +177°C (-350°F) are available.
Humidity
Standard ranges available are: 20% to 95% ±5% RH. 10% to 98% ±2% RH. Different ranges available including special dehumidity ranges to 5% RH.
Humidity System
Two Humidity systems are standard. The conditioned fine Mist System utilizes your plant water supply and a fine mist is sprayed over stainless steel sheath type heater to create steam. This steam is then carried by the circulation system throughout the room. This system is recommended when doing continuous testing with high live loads. All steam is created within a plenum outside the room area. Our Steam Generator System utilizes an external self-contained steam generator with all safety controls, water level controls, etc... to provide humidities to saturation within the room. This system is recommended for rooms being used for low and high humidity testing within the range of +40°F to
+130°F.
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Temperature Humidity Cabinets