Lechler VarioJet nozzles atomize according to the principle of internal mixing. With this twin-fluid nozzle, the water is fed in axially. After arriving at the distribution plate, the liquid is split up into a thin liquid film. This thin liquid film is split into finest droplets by the atomizing air in the mixing chamber. The resulting two-phase mixture is then atomized a second time when exiting via several bore holes arranged in a circular fashion.
In addition to the VarioJet nozzles of the sereis VJ II-6 and VJ II-8, a new series has now been developed. The new series VJ II-3 is designed for small liquid flow rates of 0.045 - 10 l/min and currently comprises five nozzles. In this liquid range, the product portfolio of Lechler twin-fluid nozzles is extended by nozzles that produce finer droplets at small air/liquid ratios compared to Lechler Laval nozzles, while having a large spray angle. Fine droplets and a large spray angle are an ideal condition to accelerate heat and mass transfer processes. This leads to shorter evaporation times in gas cooling or to faster reaction times in the injection of ammonia water for DeNOx-systems.
Spray pattern of a VarioJetnozzle (far left) and the Lechler VarioJetnozzles product line (VJ II-3, VJ II-6 and VJ II-8, left to right)
The benefits of the VarioJet II-3 nozzles are their lower operating costs (since less atomizing air is required), their large control ratio of up to 50:1 and their variably adjustable droplet size.
Thanks to the innovative design of the VarioJet II-3 nozzle, a spray with a large outlet angle is achieved. This is characterized by an even liquid distribution as well as a fine droplet spectrum with a low specific air consumption. The fineness of the droplet spectrum is decisively influenced by the air/liquid ratio and by the pressure level of the two flow rates. As a general rule: the higher the air/liquid ratio and the higher the pressure level of atomizing air and liquid is, the finer the droplet spectrum. The large free cross-sections in the nozzle keep the risk of clogging and the maintenance effort to a minimum.
Features of the Lechler VarioJet II-3 nozzle at a glance:
- Large spray angle (60°, 90°) for a good coverage of the cross-section of the duct
- Wide fluid control range up to 50:1 (complete VarioJet series: 16:1 to 55:1)
- Large liquid range from 0.045 – 10 l/min (complete VarioJet series: 0.045 – 150 l/min)
- Typical pressure range: liquid 1 – 10 bar,ü; atomizing air 1 – 6 bar,ü
- Adaptation of the droplet spectrum by changing the air/liquid ratio
- Fine droplets at low air consumption
- Less sensitive to clogging due to large free cross-sections without fixtures
With the new generation of VarioJet II-3 nozzles, several case studies for evaporative coolers have shown that with nozzle substitution by VJ II-3 nozzles, a reduction of up to 60% in the amount of atomizing air required can be achieved, which also means a considerable reduction in energy costs.
Detailed product information about Lechler VarioJet nozzles are available here.
Overview