In 1952, Tretyakov developed a shield similar to the Nipher based on wind tunnel tests.
The Tretyakov windbreak ring is equipped with vertically circular metal blades. The metal blades are horizontally movable and conically converge at the base of the rain gauge. The individual blades are connected to each other by a chain, which provides excellent aerodynamic properties.
The Tretyakov windbreak ring consists of:
· Standpipe for the rain gauge
· frame
· Metal slats
· Small parts for assembly
1. Measuring height
The wind protection according to Tretjakov is used for the measuring heights:
· 100 cm
· 150 cm and
· 200 cm
offered.
The existing foundations and threaded pins on the measuring field are used for installation.
The windshield is made of V2A 1475. A service life of 10 years is guaranteed for use under average meteorological conditions. This guarantee cannot be given for use on islands.
2. Structure
2.1. The Ring
The Tretyakov windbreak consists of 24.35 cm long, circularly arranged metal slats. The metal strips are trapezoidal and U-shaped. The windbreak is height-adjustable.
The arrangement on the circle with a diameter of 1060 mm is carried out at the same distance using slots.
This also ensures that the metal slats can be easily replaced.
The slats are arranged so they can be moved vertically. This allows them to swing depending on the direction of flow and wind speed, with the aim of reducing turbulence at the rain gauge and thus increasing collection efficiency.
The design provides for a pendulum range of 30°.
3. Modifications
The aerodynamic shape of the upper ends of the metal fins was omitted because it would cause snow to accumulate. The deposition of solid precipitation leads to a delayed precipitation measurement when the precipitation is carried into the sensor by wind.
The windshields modified in this way have been used successfully in the CHMI precipitation measurement network for years in the version offered.
The metal slats are connected at the bottom with a V2A cable. The plastic parts shown will be replaced with V2A components.
The rope limits the pendulum movement and increases the rigidity of the system, which keeps the metal slats on the ring at higher wind speeds and increases the effectiveness of the overall system.
4. Maintenance
To facilitate maintenance of the rain gauge, one element of the ring is designed to be hinged. The element is attached with wing screws and can be removed without tools.
5. The frame
The supports are at a 120° angle They are mounted offset and taper towards the foundation base. The supports are secured using the pins provided on the foundation.
The supports and all connecting components are made of V2A stainless steel. The entire structure is also height-adjustable at the supports. This allows the system to be re-levelled and adapted to the requirements of the measuring point.
6. Miscellaneous
The windshield can be retrofitted with a holder for an anemometer to correct the precipitation values.
