Drying with air knives: fast, even and energy-efficient
Drying with air knives: fast, even and energy-efficient
Washed bottles that have to be labelled, crates from the washer, cans that come out of pasteurisation wet: in production lines, products constantly have to be dry quickly and completely. Drying with air knives is the technique of choice for this, provided the air knife and the blower are properly calculated for each other and for the product. That is precisely where DOVAC is strong.
Drying at line speed: how an air knife works
An air knife is a slot-shaped blowing profile that directs a thin, even airflow across the full width of a product. The product passes under or alongside the air knife on a conveyor belt or drum, with the airflow pushing water, ice, crumbs or loose particles off the surface. A blower or turbo blower delivers the continuous airflow, which is fed through hoses to one or more air knives. Unlike drying with heat, this happens mechanically and directly, at the speed of the line.
By far the greatest share of air knife work, some 90 to 95%, is in the food and beverage industry: drying bottles and buckets before labelling, drying packaging after pasteurisation, blowing crates dry and clean, drying washed eggs, fruit and vegetables before packing in carton, blowing products ice-free out of the freezer and blowing away residual material for reuse. Beyond that, the technique is used for, among other things, blowing sprayed pallets dry.
Air knives are moreover used not only to dry products, but also to blow surfaces clean, remove residual material and make products ice-free. That makes them suitable for a wide range of production processes.
The problem: wet product and expensive compressed air
Wet product is a source of failures and quality loss further down the line. At the same time, blow-drying is in practice still often solved with compressed air from a compressor, and that costs a lot of power. On top of that, an air knife installation only performs if the sizing is right: the width of the product determines the length of the air knife, and the line speed, the amount of moisture and the distance to the product determine which blower is needed. The closer the air knife is to the product, the more effectively it blows.
The risks of half-measures
Anyone who does not solve the drying problem, or only half solves it, sees it immediately in the end product:
- Labels that will not stick to wet or iced bottles and packaging
- Soaked carton that loses its strength and collapses
- Oxidation and rust on cans that come out of pasteurisation wet
- Crumbs and residual moisture spreading through the line
And anyone who does solve it, but with compressed air, is structurally paying too much: the compressor consumes considerably more energy than a properly calculated combination of blower and air knife.
Because drying installations often run continuously, energy costs mount up quickly. That is precisely why a properly calculated air knife installation often delivers an attractive payback period within a relatively short time.
Our possibilities
Air knives
An air knife dries, cleans or de-ices products and conveyor belts in a single pass, running on a blower instead of compressed air to save energy. We calculate the right combination in advance.
Side channel blowers
Side channel blowers move large air volumes, suiting aeration, conveying and porous materials. Oil-free and low-maintenance, from compact single-stage to two-stage models, including ATEX.
Turbo blowers
Turbo blowers deliver a steady airflow at high efficiency and low noise. Direct drive matches output to demand, cutting energy use substantially.
Benefits for your business
A properly calculated air knife installation delivers:
- Dry products at full line speed
- Less loss and fewer failures in labelling, packaging and further processing
- An even drying result across the full product width
- Structurally lower energy consumption than drying with compressed air
- Insight into the payback period before you invest
The solution: air knife and blower, calculated and from a single source
For each application, DOVAC calculates which air knife and which blower deliver the required result, and then supplies the complete installation in-house: the air knife in aluminium or stainless steel (the latter for hygiene-critical environments such as the food industry), the blower or turbo blower, hoses, hose clamps and filters. You have one party for the calculation, the delivery and the maintenance. Where competitors regularly recommend a compressor, DOVAC deliberately opts for the blower solution, because it delivers the same result at considerably lower energy costs.
In doing so, the focus is not only on the right blower and the right air knife, but also on the optimum positioning, blowing angle and distance to the product. It is precisely that combination that ultimately determines the drying result.
Which air knife solution suits your drying process?
DOVAC supplies complete air knife installations for drying, blowing clean and de-icing products on a conveyor line. Which version is suitable depends on, among other things, the product width, line speed, amount of moisture, required dryness and the available distance to the product.
The delivery programme includes:
- Aluminium air knives: suitable for general industrial drying and blow-clean applications.
- Stainless steel air knives: intended for hygiene-critical environments, such as the food and beverage industry.
- Blowers: for a continuous, energy-efficient airflow at a wide range of line speeds and product dimensions.
- Turbo blowers: for applications that require a higher air output or a more powerful, precisely calculated airflow.
- Complete installations: including air knives, blower, hoses, hose clamps and filters.
- Replacement of compressed air: for existing drying processes in which a compressor consumes unnecessarily large amounts of energy.
DOVAC does not simply select individual components, but calculates the combination as a single system. The length and positioning of the air knife are matched to the product, while the line speed, amount of moisture and required blowing force determine which blower is needed. The result is an installation that dries sufficiently without consuming energy unnecessarily.
Arrange a demonstration
Are you currently drying with compressed air, or is your line held up by wet products? Contact DOVAC for a calculation of your drying process and a demonstration on site, and discover how much energy you can save compared with drying with compressed air.
Why choose DOVAC?
A large stock of our own, available immediately
A product is no use if it arrives in eight weeks. That's why DOVAC keeps a large stock of its own, including filters, valves and maintenance kits.
Extensive experience with air knife installations
DOVAC has extensive experience with air knife installations for drying and cooling.
The difference lies in the calculation
The difference lies in calculating the air knife, blower and positioning.
See that it works first, then buy
DOVAC first demonstrates on site that it works, then you buy.
