RFQ: High-Range Optical Dew Point Hygrometer

Descriptions

NPLs requirement is for a high-range hygrometer with the ability to measure up to +95 °C dew-point temperature with an accuracy of ≤ ±0.1 °C. The purpose is to give confidence to the humidity generated by NPL's primary standard generators. Allowing us to perform maintenance activities and ensuring our ability to deliver our stated international CMCs (Calibration & Measurement Capabilities), as well as enabling its use as a reference standard hygrometer for comparison calibrations. The setup needs to allow for two separate scenarios. In the first circumstance, the test gas will be supplied to the hygrometer inlet from an NPL primary standard generator at 105 kPa and be vented to atmospheric through a rotameter with a needle valve assembly for flow control. In the second circumstance, the hygrometer must have an internal pump that samples gas from a temperature and humidity chamber.