Vaisala Filling Balance FB13 facilitates the use of radiosondes. It is used as ballast for obtaining the correct nozzle lift (free lift plus payload) for the sounding balloon. Nozzle lift refers to the weight a balloon is capable of lifting when filled. In addition, the balance also acts as a gas inflation pipe.
FB13 contains 2 different nozzles for convenient attachment of balloons with small and large neck diameters.
The balloon neck is secured on the nozzle with a spring clamp. Each nozzle has a clamp of its own, and the nozzles are easily interchangeable.
- 1
- Nozzle
- 2
- Spring clamp
- 3
- Weight plates
During balloon filling, the required nozzle lift is obtained by loading the nozzle with additional weight. Nozzle lifts from 0.4 kg to 2.8 kg for the big nozzle, and from 0.3 kg to 2.7 kg for the small nozzle, can be obtained by loading weights in intervals of 0.1, 0.2 and 0.4 kg onto the nozzle. See the following table for details.
| Part | Weight | Quantity |
|---|---|---|
| Nozzle, Ø 42 | 0.4 kg | 1 |
| Nozzle, Ø 20 | 0.3 kg | 1 |
| Spring clamp | 2 | |
| Additional weight | 0.1 kg | 1 |
| Additional weight | 0.2 kg | 2 |
| Additional weight | 0.4 kg | 5 |
The nozzles are made of aluminum, and they are grounded to remove possible static electricity formed during the balloon inflation. The weights are made of stainless steel.
The side tube of the nozzle is connected to the gas cylinder or gas piping system with a flexible plastic hose (inner diameter 1/2"). It is recommended that the gas cylinders are furnished with a pressure reducing valve. A simple screw valve can also be used.
Pressure reducing valves of conventional type with built-in back pressure valves and 2 pressure meters can be purchased locally. The first pressure meter indicates the pressure inside the cylinder, and is a gauge for estimating how much gas is left in the cylinder. The second is a low pressure meter that indicates the highest permissible pressure on the outflowing gas. This pressure must be adjusted according to the required speed of gas flow.