|The chamber shall be of mono block structure construction, comprising three cabinets placed one above the other (Hot cabinet at top, ambient cabinet at middle and cold cabinets at bottom).
|The exterior housing must be made from lightweight, self-supporting, corrosion resistant, galvanized steel-sheet of suitable thickness. The outside surface of the exterior wall shall be primed and painted to a standard finish with high quality materials.
|Complete construction of the inner testing spaces shall be made of Stainless steel
|All the joints shall be continuous seam welded to form a hermetically sealed unit in order to prevent external moisture migration.
|The inner shell shall have good suitable thickness and structural rigidity to withstand thermal induced thermal stress.
|Inner wall shall be connected to external wall suitably.
|Upper test cabinet shall be hot cabinet and equipped with fan, heaters, temperature sensor, thermostat etc.,
|Middle test cabinet shall be ambient cabinet and equipped with fan, heaters, evaporator, temperature sensor, thermostat etc.,
|The lower test cabinet shall be cold cabinet and shall equipped with fan, heaters, evaporator, temperature sensor, thermostat etc.,
|All the fan motors shall be placed outside the test space with suitable protection.
|If cooling by LN2 injection method an appropriately sized port shall be provided at the centre of the cold test room wall to vent the vaporized LN2 so as to avoid over pressurization in the test space.
Materials used in testing room size conditioning shall not generate any corrosive elements like sulphur, chlorine etc.,
|Temperature sensor or any other items in the test cabinet shall not protrude into the usable testing volume of specimen carriage basket.
|Suitable environmental friendly, low thermal conductivity, high density and non hygroscopic insulation material shall be provided between interior and exterior of the chamber and also between the test cabinets. Asbestos insulation or hazardous substance shall not be used. The thickness of the insulation shall be such that to ensure the following conditions:
|The outer wall surface temperature of the cold cabinet shall be ≥ 20oC, when cold testing room is maintained at -180o C in continuous operation.
|The outer wall surface temperature of the hot cabinet shall be ≤ 35o C, when hot cabinet is maintained at +250oC in continues operation.
|Test Specimen Carriage Basket:
|The chamber shall be provided with electrical driven actuator / pneumatic piston actuator to transfer specimen holding carriage (Basket) between the test cabinets. Clear basket dimension shall be ≥ 500mm (D) x ≥500mm (W) x ≥500mm (H). The basket shall be transferred vertically between the test cabinets in short duration (≤ 10 seconds) without jerk & mechanical shock after the lapse of the set time in each cabinet. The basket shall be made of stainless steel mesh to facilitate good air circulation.
|Travelling Cable Port:
|The chamber shall be provided with travelling cable port at test specimen carriage basket for the usage of temperature sensors and signal wires external from the test package. Any part of the travelling cable port shall not protrude into the usable test room’s volume of the basket. Travelling port inside shall be Teflon sleeved and clear inside dia shall be ≥50mm.
|The chamber shall have door at front side. The door shall be fully open able (180C or more) to facilitate test article loading and unloading
|Heaters shall be provided at the door at appropriate place to avoid moisture condensation on the outside surface.
|Suitable numbers of locks / clamps shall be provided to ensure uniform pressure and air tightness of the thermal shock chamber testing room.
|Window and Interior Lights:
|The chamber door shall have multi-pane observation window of size ≥ 0.3m x 0.3m to view/inspect the test sample/ specimen in the ambient cabinet. The test room shall have proper lighting for functional inspection.
|Condensation Water Drain:
|A backpressure free automatic drain shall be provided at cold room and ambient room to remove humidity/condensation water.
|The chamber shall be designed to conduct thermal shock tests as per the international standards (MIL-STD, IEC, DIN, etc.) as applicable.
|Run Time Meter:
|Run time counter shall be provided for recording the total running time in hours of the chamber
|Thermal Shock Chamber’s Safety
|Audio / Visual Alarm system on machine & computer for fault reporting.
|Chamber protection during power failure, power surge, low power, fluctuating power or power reversal.
|Prevention of condensation on test samples.
|Fuse protection for mains and individual circuits.
|Over temperature safety cut off thermostat with audio alarm.
|Integral Fault Diagnostic system/Auto diagnosis program for safety with troubleshooting for equipment.
|Auto/self adapting power control of cooling system.
|High and low temperature protection for testing samples.
|Door opening electrical switch control with chamber conditioning fan.
|Test cabinet fan interlock for Heaters and Refrigeration.
|Factory set high heat limit.
|All electrical & electronics components should be CE marked components.
|Safety interlocks to prevent basket transfer when chamber door is open.