Instron offers the latest range of 3119-600 Series environmental chambers that has been specifically developed for usage with dual column table model testing systems. The range contains three height options, wherein each option can provide temperatures ranging between -100° C and +350° C, according to the choice of cryogen. An optical quality, heated window and removable wedge ports are included in all the models. The heated window helps preserve window clarity while testing below ambient temperatures.
The environmental chambers employ a forced-convection principle in which hot or cold air is made to re-circulate around pull rods, grips and the specimen to offer reduced thermal gradients, maximum heating or cooling rates, and improved thermal stability. Additionally, air circulates around the outer skin of the chamber to keep it cool.
The product features of the 3119-600 Series chambers are:
- Removable wedges and a handy cut-out port for instrumentation cabling
- Heated window offers enchanted frost-free performance
- Fast/Slow fan speed
- 12V Halogen internal light
- USB interface for communication with computer
- Twist lock removable mains cable
- 0-10V DC-Out
To choose the required set-point temperature, a Eurotherm 3208 temperature controller which is mounted on the chamber is utilized. A sophisticated functions option facilitates PC communication through USB and 0-10V analog output, defined heating rates and enables dwell times (8 segments). Through the new version of Bluehill 3 Software (version 3.31), users can directly control the temperature from Bluehill 3.
Liquid Nitrogen (LN2) is generally preferred for the following reasons:
- LN2 enables a lower minimum temperature from 100° C to -150° C, while CO2 allows a minimum temperature of -70° C.
- When compared to CO2, LN2 is easily available in huge quantities. Dewars for storing LN2 are often large, while CO2 is generally utilized in standard size gas cylinders that have to be changed often.
- When compared to LN2, CO2 has additional associated safety hazards.
Customers can consult their supplier for more details.
Occasionally Carbon Dioxide (CO2) offers a suitable option for the following reasons:
- LN2 is often lost when stored in a Dewar flask that is not in use. On the other hand, CO2 can be stored for extended period of time without any loss. This aspect offers an advantage for occasional users of CO2.
- Since CO2 has higher cooling power over LN2 per unit volume, the specimen, the chamber air temperature, and fixtures will reach the desired temperature quicker than with LN2.
- Losses from CO2 carrying pipe work are comparatively small in contrast to losses from LN2 pipe work. Additionally, with LN2 it is important to insulate hoses and associated pipe work properly.
In order to increase the cooling power and reduce the losses, the cryogenic supply should be placed very closely to the chamber.