Thermal and Water-vapour Resistance Tester

Introduction
The instrument is a special measurement device used for measurement of thermal and water-vapour resistance under steady-state conditions (?sweating guarded-hotplate test“) of textiles according to ISO 11092.

 Working principle
The test method, as described in ISO 11092, is based on measurement of the heat losses through the sample in stable temperature (thermal resistance). Sample is placed on the hot plate; the hot plate is surrounded with active heat shields on all sides except for the side with the sample. Electrical power required to hold the hot plate temperature stable is measured and converted to temperature resistance of the sample: the better temperature resistance (better insulation), the lower power is needed.
The sample can be precisely moisturized in order to simulate human perspiration (and measure water-vapour resistance). To achieve this, the hot plate is porous and water can be pumped into the assembly. A digital regulator holds constant level of water/vapour mix in the hot plate assembly. The sample does not soak up with water as the sintered material of the hot plate is permeable only to water vapour.
The sample gets wet with the water vapour and is chilled with a wind, simulated with tangential fans: just like when wearing sweaty clothes. The air speed and turbulent flow are electronically regulated. The water-vapour resistance is then measured from the hot plate heating power requirements.

Structure
The device consists of two parts: the hot plate device unit (HPD) and a trolley. The HPD is inserted into a customer-supplied climatic chamber. The trolley is then connected with the HPD by means of a water hose and an electrical connector.

Features
WATER CIRCUIT wets the sample. As the sample dries, the device adds water under the porous hot plate. An insertion of a cold water can cause inaccurate results, so we heat the water in a two-stage pre-heater.
 
UNIFORM HEATING of the hot plate is important for accurate results: we use copper layer to achieve high uniformity. In addition, our temperature regulators measure temperature with 0,018 °C resolution.

EQUIPMENT DRAWER
The trolley includes an equipment drawer and a shelf to store all documents and small parts.
 
USE YOUR OWN CLIMATE CHAMBER
The device fits in all climate chambers that can accommodate 550x430x600 mm (customizable).
 
RUNS WINDOWS
No special computer needed. We use a Windows 10 based touch notebook computer with Ethernetand Wi-Fi: it would be easy to store the reports on your network.
The measurement application is free, in English or Czech. We can even do remote support!