Perfect dosing and shut-off

The Warex rotary valve can be used as a dosing and shut-off valve and, thanks to its advantages, is especially suitable for use with bulk goods.

Warex Valve GmbH based in Senden in the Münsterland region has made a name for itself in the development, production and delivery of reliable and economically attractive shut-off devices throughout its more than 50-year company history. The products, which are used worldwide in the chemical, food and pharmaceutical industries as well as in plant and container construction are particularly suitable for demanding operating conditions and challenging applications. The butterfly valves in the “Rotary Valve” series have also proven themselves extremely well in their field of application in the bulk solids industry. The two models, “Rotary Valve DKZ 103 APS” and “Rotary Valve DKZ 110 APS”, are based on the continuously further developed butterfly valves in the centric APS series from Warex. The shut-off function involves the sealing element being pneumatically pressed against the valve disc. This so-called APS (air-pressure-sealing) system, ensures that in the “closed” position, the entire circumference of the seal is uniformly inflated to adapt to the full circumference of the disc. This technique provides a number of advantages, both in terms of pressure-tight shut-off and low-friction, material-friendly operation. The impeller-like valve disc – the rotor – on which the product name is based ensures extremely precise dosages. Various models (diameter, speed, density of medium) are available. The customer benefits from a product that is perfectly designed for the respective tasks thanks to application-specific options regarding material and drive type. Depending on the sealing material used, the temperature range for applications is from - 40 °C to + 200 °C. If the transported medium is expected to reach a temperature of 130 °C and higher, for example in the case of plastic granules or products and raw materials in the food sector, silicone seals are used.

And at a further stage, i.e. at even higher temperatures, it is also possible to offer rotary solutions with metallic sealing. Although pressure tightness cannot be ensured here, materials such as most types of granules are unable to pass through due to the small gap size.

Especially with abrasive media, for example in the concrete and cement industries, the wear occurs due to the transported medium wearing away material both from the rotor and from the interior of the butterfly valve seal. Soft-sealing rotary valves can thus be used reliably in this area because the abrasion is greatly compensated by the inflatable seal. Up to a certain degree of wear, the loss of material is fully compensated thanks to the highly adaptable cuff still providing reliable sealing. The maintenance and repair intervals are significantly longer than with conventional methods, ensuring greater economy. A further advantage is that the seals are normally interchangeable. Ideal for explosion-proof conditions is the Rotary Valve DKZ 103 / 110 APS in accordance with the Atex type examination BVS 03 ATEX H024 X N6.

A wide range of applications

Another application for the rotary valve is the use in vacuum transport systems. Depending on the thickness of the transported material, the pipe system is either partly, or, in the case of easily flowing products, completely filled. The rotor provides uniform portioning right up to a full flow in the 22° position. The wide range of application possibilities include the chemical, pharmaceutical and animal feed industries as well as the food industry. One example of an application is the production of peanut butter. Rotary-type butterfly valves can be used very successfully here thanks to their special properties: the dosage is very gentle, thus ensuring that the raw material – peanuts – is not damaged, crushed or smeared during the process.

The intelligent design of the rotary valve allows the mounting of various relatively small and therefore energy-saving drives. Here we distinguish between the 180° pendulum-type drive (pneumatically operated) which always provides half the capacity of one full revolution of the rotor, and the electric drive. Electric drives allow the precise setting of the revolutions of the rotor to match the dosage. Thanks to the low installation height and compact construction, the rotary valve can, among other things, also be incorporated into existing systems in a space-saving way, which makes refitting or upgrading a very attractive option.


Veröffentlicht in:
CPP 03/17, S. 33