The Features Of Shaw Dewpoint Meters And Sensors

The Shaw Dewpoint Sensors were developed over 50 years ago and are still the most superior direct dewpoint sensors on the market. Substituting as a variable capacitor, the dielectric layer is just a couple of microns in thickness for quick equilibrium with the surrounding water vapor pressure, and the corresponding value is converted by the meter in dewpoint temperature.

The Shaw Dewpoint sensor is a costly, sensitive piece of equipment that should be treated with the utmost respect. Keeping the sensor in similar environments over a long period of time will distress the sensitivity of the sensor, making it slowly diminish away. It can take a week to recover or even be irreparably damaged.

You should take note that the Shaw sensor installed in, for example, a dryer at stable dewpoint is not to be considered as “similar conditions.” Since there will be alteration of pressure, airflow and eventually dewpoint.

The manufacturer supplies the dewpoint sensor in an aluminum container with desiccant. Although the container is a great method of transportation and temporary storage, “similar conditions” may follow if the sensor is kept there for several months or more. The engineers of JLC International suggest exposing the dewpoint sensor to ambient air for a few days here and there to improve its sensitivity, performance and life span.

The most unique and important aspect of the Shaw dewpoint sensor is the “Automatic Calibration” ability. Each dewpoint sensor is manufactured so as to saturate with water vapor at its design maximum. The sensor will swiftly come into equilibrium at its design maximum and will not react to any further moisture, when exposed to moisture above its maximum operating range. This is how the basis of “Automatic Calibration” is formed.

The dewpoint sensor can be simply calibrated by exposing it to any atmosphere that is “wetter” than the operating range of the device and modifying the calibration control on the electronic panel. Usually room air is sufficient for exposure.

Re-calibration can be conducted in-situ, without resorting to any special skilled personnel or equipment.

Over the equipment’s usual operating lifespan of 15 years, the Shaw Dewpoint sensor doesn’t drift outside the given tolerance. To compensate for the natural drift of the electronics and the sensor drift, the engineers of JLC International recommend executing the “Automatic Calibration” method every several months.

While all Shaw Dewpoint Sensors are similar, they are not identical. Every sensor of the same range – or color, if you prefer – should be tuned in with the electronics in agreement to the “Automatic Calibration” procedure.

In addition, the Shaw Dewpoint Sensor has a capacitance probe for fast system response and is intrinsically safe when used with Shaw meters. It has an automatic zero setting on most sensor ranges and is supplied with a stainless steel sensor holder for easy piping. There is a two-year guarantee on the sensor and a six-month guarantee on the Gray Spot Low Spec.

For more information about the Shaw Dewpoint Sensor, explore our website or email jlcusa@jlcinternational.com