The 700-10LTA Ozone Test Chamber provides continuous uniform, accurate and reliable temperature and ozone control. The measurement and control system consists of the STAT-1900 Single Setpoint temperature controller for uniform thermal performance under all loading conditions and the Mast Development 727-3A Ozone Monitor with power flow control assembly to ensure uniform and constant control of ozone levels. Low cost, featuring steady state auto control and recording.
Temperature Range: +15º C above ambient to +343º C (+650º F)
Temperature Uniformity: ±1% of setpoint
Ozone Control: ±4% of setpoint
Control System: Single setpoint controller
Applications: Accelerated and continuous duty ozone testing of rubber and plastic components. Designed specifically to meet the stringent testing requirements of the American Society for Testing and Materials (ASTM) test method D1149 and ISO 1431, parts 1 and 2.
Steady State Control
This chamber incorporates solid- state electronic instrumentation for precise temperature regulation. Integral over temperature protection is standard. The STAT-1900 microprocessor-based 1/4 din single loop temperature controller features a bright LED display that shows setpoint oven temperature, control output, etc., during oven operation. Indicator LEDs on the controller face log alarms and control output status during the work cycle. All data input and control selections are made through the membrane key pad. A sheathed thermocouple is part of the control system to monitor oven temperature. Hardware and software interlocks prevent accidental data loss or change.
Over Temperature Protection
Temp limit overtemperature protection is a standard feature of the 700-10LTA control system. A 1/4 DIN control, Temp limit protects the oven and your product during temperature fault conditions. Heaters are latched off by temp limit requiring manual reset to restore normal operation. Audio and visual alarms alert the operator of fault conditions. This instrument is FM approved as an overtemperature alarm device.
Construction
The chamber housing is manufactured with 16 gauge heavy duty steel and is completely welded for strength and reliability. The backed on blue enamel finish provides long lasting corrosion protection. Type 304 stainless steel interior provides excellent corrosion resistance to ozone. The chamber has four full inches of fiberglass insulation to minimizes heat loss. The door is designed with a silicone door seal for positive sealing and also includes a glass observation panel.
Theory of Operation
The Model 700-10LTA is simple to operate and versatile over a wide range of temperatures, airflows and ozone concentrations. Users confirm its ozone concentration stability and dependable operation. The entire system is diagrammed below.
Generation
The ozone source is a mercury vapor quartz ultra-violet lamp. It is housed in a protective metal container outside the test compartment as required by ASTM and is easily accessible through the lower side door.
Air Recirculation
Plenum chambers located on each side of the all stainless steel test compartment direct the ozonized air through it. A wheel type blower in the left plenum chamber provides two-feet/second air recirculation velocity over the test samples. The blower wheel is shaft-mounted with the drive motor mounted outside the test compartment, as required for the ASTM tests.
Air Flow System
Fresh air is drawn into the system with a rotary vane type Gast "oil-less" air compressor. Felt filters on both the intake and exhaust sides of the compressor remove particulate contamination. The rate of airflow is observed on a flowrator and set with the "air flow control," a valve in the compressor by-pass line. Air leaving the flowrator then passes in small part thru the computer controlled regulator over the ultra violet lamp and in large part through a lamp bypass line. The ozonized air from the lamp is remixed with the bypassed air and enters the test compartment circulation system. A freshly ozonized airflow replenishes the air in the test compartment approximately once a minute at the recommended flow rate of six cubic feet per minute. Only fresh air is passed over the ozone source as recommended by ASTM. Air in the test compartment is exhausted outside and is not recirculated over the ozone source.
Tempertaure Control
STAT-1900 digital temperature control provides automatic temperature control over a range to 300 ºF and a tolerance of plus or minus 1/2ºF, as measured with a highly dependable fully compensated cold junction type T thermocouple in the chamber air stream. In order to achieve this remarkable control despite ambient temperatures up to 100ºF, a finned stainless steel cooling coil is employed.
The heat is supplied by an open wire (non-corrosive) element of Blue M modular disc design, which offers oven performance unmatched in the industry. The design is such that over 85% of the open wire coiled element is exposed to the high volume chamber air stream. Thermal lag is virtually eliminated with this unit.