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COMETEO Multi-Plate Radiation Shield for Weather Sensors, Actively ventilated - built-in fan requires 12Vdc voltage

code: F8200

Professional actively ventilated solar radiation shield for better protection of thermometers hygrometers barometers and dataloggers for more accurate measurement.


Multiplate radiation shield is used to protect weather sensors and provides more accurate measurement results. The shield minimizes radiation reaching the sensor, minimizes radiation absorbed by the shield and maximizes ambient air flow around the sensor. The enlarged top plate „cap“ is 210mm in diameter and designed to provide shade for high solar angles for lower plates and also for full protection of measuring device placed underneath.

Optimized design combines all excelent features of multi-plate shield with effective active ventilation by means of a high performance fan powered from external 12Vdc voltage. The unique design allows the use of a low energy fan that minimizes potential sensor's parasitic heating from the fan motor.

The most important advantage of artificial ventilation of the shield is the reduction of the daytime radiation error especially in calm days with low winds.

 

"Not only radiation shield, but the complete COMETEO system minimizing negative effects"

 

Included in delivery:

  • Assembled F8200
  • Mounting accessories
  • User manual

Works with COMET instruments - see OPTIONAL ACCESSORIES


Request your free COMETEO shield for six months evaluation.
If you are satisfied after testing you can buy the shield, otherwise return it.

 

Technical data

Value
Measured value Temperature
Relative humidity
CO2
Atmospheric pressure
GENERAL TECHNICAL DATA
Supply voltage 12 Vdc
Power consumption of fan 0.6 W
Pulse output 2 pulse / rev. (max. current of output is < 5 mA, the pulse output is not protected against short circuits)
Temperature operating range -30 to +80 °C
Relative humidity operating range 0 to 100 %RH
Storage temperature range -30 to +80 °C
Storage relative humidity range 0 to 100 %RH (no condensation)
Dimension 220 mm (diameter), 250 mm (height)
Weight approx. 900 g
Material ASA - UV stabilized, antistatic
Warranty 3 years

Features

F8200
COMETEO is made of ASA plastic which is resistant to mechanical damage and UV radiation. ASA plastic is very stable over time.
F8200
Transmitter is entirely protected inside the radiation shield by maximized top cover area which provides advanced weather protection.

Air Temperature in Meteorology

The measurement of air temperature in meteorology is a difficult task. Accurate air temperature measurements require minimization of local effects (e.g. trees and buildings) and minimization of environmental effects that influence the actual sensing of the temperature at the position of the sensor. World Meteorological Organization - WMO defines internationally  the temperature of the air nearby the earth's surface as “the temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation” (WMO, 1992).

The main functions of thermometer shields are to protect the sensor from direct or indirect radiation from the sun during the day and from radiation from the sensor to the sky at night and to protect the sensor from wetting. Wetting of the sensor and screen is caused by fog, drizzle or rain. But protection against radiation and wetting conflicts with the requirement of sufficient ventilation. Due to insufficient ventilation a microclimate develops within the screen. In fact, all screens develop their own microclimate and the difference with the ambient climate depends on screen type and design.   It may be stated that the larger the bulk of a screen, the stronger the microclimate within the screen and the more the sensed temperature deviates from the real air temperature. From the above, it follows that thermometer screens should have a high reflectivity to minimize heating of the plates and subsequent warming of the air as it flows over the plates to the sensor. To decrease the time the air is in contact with the plate, the plate radial distance should be as small as possible. To prevent the development of microclimates within screens, also the blockage of ambient airflow by the screen should be minimized by making the plate spacing as large as possible, taking into account the requirement that wetting of the sensor should be prevented. Any design of a thermometer screen is a result of compromises. Finding the optimal design is a serious challenge that may require the use of different methods for studying the behavior of screens. In the field, the actual differences between the air temperature in the screens and the ambient air temperature depend mainly on the prevailing weather conditions. Furthermore, the state of the ground and humidity of the soil will also affect the air temperature in the screen as radiation or reflection will cause screen dependent biases. This can easily occur in areas with snow cover and in deserts.

The most important advantage of artificial ventilation of the shield is the reduction of the daytime radiation error especially in calm days with low winds.

Applications:

Applications - Metrology

Meteorology - COMET sensors together with COMET radiation shields are the ideal basis for weather stations for long-term weather, climate and air monitoring.

Applications - Snow Guns

Snow Guns

Application - HVAC

Building management - Our instruments which measure temperature, humidity, atmospheric pressure and CO2 are an integral part of these industry-leading solutions.