Compact Humidity Chambers

The Bemco FW1.5, mechanically cooled Compact Humidity Chamber, has a temperature range of -28 C to +177 C (-20 F to 350 F) or -73 C to +177 C (-100 F to 350 F) and a humidity range of up to 5% RH to 95% RH (see the Chart below).

This chamber features direct dry air injection and a direct humidity sensor. It operates without dewpoint limit from 5% RH to 95% RH over the range of 30 C to 85 C and allows operation at 20% RH at 5 C and 50% RH at -14 C!

This chamber provides a reliable, very low and very high, humidity testing platform with a compact footprint. Both the narrow and wide range models are housed in the same package.

Air cooled condensing and casters are standard.

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Conditioning

Chamber air is recirculated by the same high volume, stainless steel axial fan located behind a removable rear mounted diffuser baffle included on the Bemco FB1.5V Chambers

The fan is driven by a horizontally mounted motor with dual ball bearing races, connected by an extended stainless steel shaft.

A proportionally controlled single compressor refrigeration system cools the workspace on the Narrow Range System (FW1.5N) and a cascade two compressor system (one refrigeration system cools another) cools the workspace on the Wide Range System (FW1.5). Both types of refrigeration systems utilize modern environmentally friendly refrigerants. The systems include automatic hot gas bypass and suction cooling unloading.

Fast-response open type heaters, located behind a radiation baffle, raise chamber temperature as required.

Chamber humidity is increased by a Bemco mass transfer vapor generator with a sight glass, a low water cutoff, and automatic drain freeze protection. The vapor generator can be shutoff and drained when very low humidity control is desired.

Chamber humidity is decreased by the direct injection of -73 C (-100 F) dew point dry air produced by a dual bed regenerative compressed air drier furnished with an isolation valve, an inlet particulate and coalescing filter, and an outlet filter regulator.

Water and air connections are located on the top.

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Safety Systems and Electrical Wiring

All systems have thermal and current sensors on the compressor, charging valves, and numerous safety and reliability protection systems for dependable operation. All electrical wiring meets the United States National Electric Code. UL and CSA approved components are used where possible.

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Construction

The FW1.5 includes a continuously heliarc welded 304 Series stainless steel liner with high temperature fiberglass insulation. No asbestos is used in chamber construction. The outer case is fabricated from cold rolled steel finished in Bemco Blue.

A matching machinery housing is mounted on the right hand side and beneath the chamber. The FW1.5 also includes:

• A sloped roof insert to minimize potential water dripping on test objects and to meet Mil-Std 810 and Mil-Std 202. This feature reduces overall height (shown in the table above) by 1 inch.
• A trapped drain line to remove condensed water from the workspace.
• A door drip trough to catch condensed water.

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Controls

The FW1.5 is furnished with a two channel, microprocessor based, programmable 1/4-DIN, solid state, 256-step ramping controller which includes a 4-line LCD interface display, and a large red LED display.

Temperature inside the chamber is sensed by a precision thermocouple.

Humidity is sensed by a direct reading electronic humidity sensor accurate to + or - 2% RH over the dew point temperature range of -20 C to 85 C (-4 F to 185 F). This sensor is mounted through a sleeve located on the roof near the left side of the door.

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Performance

Cooling rate from 23 C (+73 F) to -73 C (-100 F) is approximately 45 minutes and heating rate from 23 C (+73 F) to +177 C (350 F) is approximately 35 minutes, both with the chamber empty on the FW (Wide Range Model).

Cooling rate from 23 C (+73 F) to -20 C (-28 F) is approximately 45 minutes and heating rate from 23 C (+73 F) to +177 C (350 F) is approximately 35 minutes, both with the chamber empty on the FWN (Narrow Range Model).

+ or - 1 C (+ or - 1.8 F) guaranteed control, + or - 0.15 C (+ or - 0.25 F) typical.

Humidity 5% RH to 95% RH, see chart. 95% RH at 85 C (185 F) maximum.

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Optional Equipment

• Window and interior light. Window size is 8.5 ” x 8.5 ” clear viewing area.
• A window wiper with an external operating handle.
• Access Ports. Sizes are 2”, 3”, 4” and 6.” One 3” access port in the left wall is provided with each chamber.
• A 5-gallon water reservoir with an internal pump, low level sensor, low level alarm, and an isolation valve to allow system operation without a source of pressurized water. The tank requires occasional manual filling.
• A single cartridge, demineralization system that produces up to 4 liters / minute of water. The demineralization system Includes a water purity indicator.
• Shelf pilasters and wire-type stainless steel shelves.
• GN2 gas purge with pressure regulator, gauge, flow measuring and regulating valved rotameter, and vent.
• Two refrigeration gauges mounted in the refrigeration compartment with or without isolation valves for the narrow range model or four refrigeration gauges mounted in the refrigeration compartment with or without isolation valves for the wide range model.

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Optional Instruments

Available instrument options include:

• Microprocessor-based, FM Approved, high over-temperature safety control.
• Set of two, one high and one low microprocessor-based, FM Approved temperature safety controls.
• Remote control over an Ethernet Link.
• 12-inch, two pen, chart printing, circular recorder.
• Pre-fixtured relay racks for mounting test items.
• Strip chart recorder.

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Available Literature Includes:

Bemco FW1.5V Series, Compact Mechanically Refrigerated Temperature and Humidity Chamber. Download FB1.5V Series Bulletin and FB1.5VN Series Bulletin, for additional information on chamber construction. Document is triple fold front and back, 2 pages, 342 KB download.

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The systems described above are our Standard Models. We make custom equipment to your specifications.  If you have any questions, need assistance in preparing a specification, or have a technical problem you want help with, we are ready.  Our quotations and advice are free.