The GLOBE Perspirometer consists of a metallic loading frame and a set of acrylic plates which can be kept in the loading frame.
The loading frame consists of two steel plates separated from each other by four mild steel rods. A set of two mild steel plates held together by means of distance pieces and springs with a dead weight are provided to apply a constant force on the test specimens placed between acrylic plates.
Loading is done by placing a calibrated dead weight on top of the upper plate of the pressing plate assembly. The guide rod attached to top plate of this assembly is locked while under load and the load removed. The springs compensate for subsequent variations in load due to variation in thickness of the test specimens on drying.
The test specimen are stitched between suitable white adjacent fabrics and dipped in either alkaline or acidic test solutions. The composite samples are placed between different sets of acrylic plates. A number of test specimens can be loaded simultaneously by stacking them one above the other.
The exposure is maintained for the specified period of time under the specified temperature. After this time period the test specimens are removed from the frame and dried. The degree of staining of the white adjacent fabrics and change in colour of the test specimens are evaluated using standard grey scales.
All the components are made of mild steel and are bright chrome plated to give them a corrosion resistant finish. Perspirometer made from stainless steel can also be supplied against special order.