FRP Series/Full Range Programmable Humidity Chambers

Control System

The FRP series is supplied with a Pro-600 Programming Control System as standard. Time vs. temperature and relative humidity profiles are programmable through the Pro600. It has two sets of controls featuring proportional, integral and derivative parameters, plus reset windup inhibit and reset clipping facilities. This control system provides control setting and indication resolution of 0.1° and +/- 0.1% relative humidity. This controller has 200 program steps for up to 99 recipes and 16 programmable events. An RS-232 communications port is included along with a menu driven software package for the customer's host computer. A host computer can communicate with the Pro-600 programmer via EIA RS-232C serial communications protocol. This interface is provided as standard in the Pro-600 control system. A free diskette for the Pro600, containing programs for setting up communications is available upon request. Other interface protocols, RS-422 and IEEE-488, are optionally available.

Recorder

Blue M's B M 7000 microprocessor- based 10" diameter circular chart recorder is standard. It is capable of measuring, displaying, and recording dry bulb temperature and % of relative humidity. All recorder functions are easily configured via the keys on the front panel. A special swing-out mounting bracket allows the recorder/controller to be pivoted from the side of the control compartment to the front if desired.

Humidity Control Method

Rather than using a moisture injection system, Blue M temperature/humidity chambers use a true vapor pressure system for humidity control. Chamber air is humidified or de-humidified using an integral water reservoir. By controlling the temperature of the water in the reservoir (thereby changing the vapor pressure above the liquid) moisture is added or subtracted from the chamber air. This technique closely approximates natural humidity control. Superior accuracy and stability, out-stripping any moisture injection method, are achieved using this method.

Horizontal Air Circulation

A high efficiency air circulation system, delivering horizontal airflow, is an integral part of chamber construction. This direct drive design has an extended shaft electric motor coupled to a stainless steel centrifugal blower wheel. Smaller models feature single blowers; the larger units have dual blowers.

Solid State Water Levelers

Chamber water usage is regulated by solid state water level controls of Blue M design and manufacture. Leveler control circuitry is designed to automatically control the Blue M water purification option. An integral reducing pressure regulator is provided for reliable operation on high pressure, in house de-ionized (D.I.) water systems Automatic Drain System The chamber water reservoir is protected by a temperature sensitive switch that automatically drains the water reservoir when the chamber temperature exceeds the boiling temperature of water.

Temperature/ Humidity Measurement

All of the models incorporate a relative humidity transmitter, or dry sensor, to measure chamber relative humidity. These sensors offer excellent control and display accuracy while eliminating the routine maintenance involved in wet/dry bulb sensing method.

The temperature measured using a separate 100 Ohm platinum Resistant Temperature Detector (RTD).

Heating

Two separate heating systems are supplied in Blue M temperature/humidity chambers; one is a dry bulb (air temperature) heater and the other is a wet bulb (humidity) heater. The dry bulb heater is a Blue M "Eterna" heating element. It has an open wire resistance heating element which provides fast, accurate response to controller heating demands. Stainless steel sheathed heating elements are used for wet bulb heating -- immersed in the chamber water reservoir. Electric power is regulated by a solid state relay and controlled from the programmer/temperature controller.

All Stainless Steel Chamber Construction

Blue M temperature/humidity chambers look good in any operating environment and they are built to last -- chamber exteriors are fabricated of Type 304 stainless steel with a brushed finish; interior surfaces are fabricated of 316 stainless steel. All seams are heli-arc welded and passivated for strength and durability. Gasketed service access panels insure vapor barrier integrity and maximum insulation effectiveness. A nominal insulation thickness of four inches is used to minimize heat gain/loss across the insulated wall. Type 316 stainless steel is used for interior construction to provide excellent corrosion resistance and long chamber life. Like the exterior, all interior seams are heli-arc welded and passivated to insure vapor barrier integrity and prevent insulation damage.

Door Construction

All chambers include inner and outer chamber doors as standard. The inner glass door provides the primary seal for the temperature/humidity environment and permits the work in the chamber to be observed during operation. Inner and outer doors are sealed around their entire perimeter by silicone sponge rubber gaskets. The chamber inner door is supplied with a wiper blade to clear window condensation for viewing.

Refrigeration System

A dual capacity cooling system -- a noncycling hermetic type -- utilizing a non CFC refrigerant, fulfills refrigeration requirements. A service panel is supplied in the left hand side of the chamber's machinery base. The use of desuperheater heat exchangers make it possible to dissipate live load wattage and/or lower the chamber temperature.

Test-Cable Lead-in Port

A 3" diameter port with rubber stopper is included as standard for passing cabling, etc, into the chamber workspace for testing purposes.

Shelves

Two shelves constructed of 304 electro-polished stainless steel are included as standard with each temperature/humidity chamber.

Chamber Options

Several optional accessories are available to help tailor Blue M temperature/humidity chambers to your application requirements.

Water Purification Unit

The WP-4800 water purification unit provides 48 gallons of conditioned water for use in the chamber's humidity and wet bulb measurement systems. The major components of the unit are a Type 304 stainless steel water tank, a quiet electric water pump, a sediment filter and a demineralizing cartridge. Provision for the WP-4800 is designed into the chamber control circuitry -- the pump is activated by water leveler demand. The chamber reservoir may be drained into the tank of the WP when the chamber needs to be drained. This water is passed through the sediment and demineralizing cartridges before being reused to remove contaminants. This feature aids the chamber in avoiding corrosion damage from the accumulated contaminants.

Truline Circular Chart Recorder

Certain testing criteria require greater chart resolution than obtainable using Blue M's standard circular chart recorder. For these applications, a Honeywell "TRULINE" circular chart recorder option is available. This option has a 12" diameter chart that provides 34% greater chart area than a standard 10" diameter recorder chart. The unit prints its own chart with a thermal dot matrix stylus at the same instant that it is printing the process temperature and relative humidity.

Caster/Leveling Legs

Large, phenolic, swivel casters and sturdy leveling legs can be installed to enhance the mobility and setup of Blue M chambers. The legs are threaded rods, with locking nuts and no-mar phenolic feet. Once the unit is in position, the leveling legs may be adjusted to level the unit and pick the casters up off the floor.

Drip Shield

Certain high temperature/high humidity conditions can produce condensation on the ceiling and walls of the chamber workspace. The addition of the Type 316 stainless steel drip shield prevents condensation on the ceiling of the chamber from falling on the workload and causing damage (it is routed down the back wall of the chamber, where it returns to the chamber water reservoir).

Glove Ports or Port Plugs

Glove ports can be installed in the inner door to allow the operator to manipulate the product under test. This option includes neoprene rubber gloves installed through the inner glass door, below the viewing window. Some processes require small parts or tools to be introduced to the work space during chamber operation. In these cases, port plugs are installed through the inner door. These are 6" diameter stainless steel plugs, held in place with DeStaco clamps. Like the glove ports, these entrances are installed below the viewing window.

Use of these options is not recommended at chamber temperatures over +50°C.

Lead-in Ports

Additional lead-in ports may be installed in the chamber in addition to the standard port. Larger port diameters are available upon special request.

Extended Temperature Range

High Temperature: the temperature range of Blue M temperature/humidity chambers can be extended to +150°C with this option. It permits dry bulb "temperature only' testing at temperatures above the normal relative humidity operating range. Low Temperature: the temperature range of the Blue M temperature/humidity chambers can be extended to -40°C with this option. It permits dry bulb "temperature only" testing at temperatures below the normal relative humidity operating range.

The chamber water reservoir is protected by a temperature sensitive switch that automatically drains the water reservoir when the chamber temperature exceeds the boiling temperature of water.

Pro-750 Programmer Controller

All chambers are available with a Blue M PRO-750 Programmer/ Temperature controller installed in lieu of the standard Pro-600 controls. Please consult with your local Blue M representative for details.

Computer Interfaces

Blue M programmable controllers come with an with an RS-232 Serial Digital Communications port as standard. However, some customers find that other interface protocols are desired For their particular use of the units. Blue M offers an RS-422/4X5 Serial Communications option and an IEEE-488 Parallel Communications option for those customers not wishing to use RS-232.

Engineered-To-Order Options

A wide variety of Engineered-To-Order (ETO) options are available to configure your chamber for its intended use. We can assist you with your needs.