Valves for Textile Chemicals Special Valves for Special Applications: There's Two for Every Case
Industrial valves in textile chemistry—A variety of different valves lead to widely differentiated overhaul expenditure and is associated with an extensive stock of spare parts. In case of a textile producer it was possible to focus essentially on compact ball valves and V–port segment ball valves.
The manufacture of textiles has been known for thousands of years and is an important characteristic of human culture. Textile products — besides everyday articles, including the diverse textile materials for technical purposes — are manufactured from both natural and synthetic fibres and their mixtures. In many textile industry companies, the route from raw material to the ready–to–use finished product involves numerous concerted mechanical and chemical treatments in order to give the goods the required user properties, the specific character and a typical and fashionable appearance.
Textile chemistry addresses chemical problems that arise in the industry during the processing of fibres. Textile auxiliary agents are special chemicals for the wide range of processing steps which ensure a trouble–free and effective production process. As a further chemical challenge, these substances must neither be toxic nor inflammable and must not pose any ecological problems.
The consequences of this are high requirements in the production of the industrial valves that are used. The Textilcolor Company in Sevelen, Switzerland, a company experienced in handling these requirements, is a good example to demonstrate the benefits of specifically used valves.
Special Material Demand Special valves
At Textilcolor, particular attention is paid to safety aspects, reliable leakproofness of the valves and the resistance of the valve materials used with regard to durability and quality of the products that are being manufactured. The chemicals used during processing, such as stearic acid, paraffins and other chemical raw materials, place different requirements on the equipment.
In the past, the company used a variety of different valves. This led to widely differentiated overhaul expenditure — and overhauling always means an interruption in production, a shut–down and costs. One should also not forget infrastructure products such as hot water and steam. These media admittedly do not pose any special challenges to the valves, but they involve other types such as flaps and on/off and control valves.
The Initial Situation
With the introduction of a process control system in 2003 and the associated modifications of the processes for improving production profitability, also the valves were scrutinised and as far as possible standardised. The company focussed essentially on compact ball valves and V–port segment ball valves (so called segmented ball valves).
A lot of different ball valve and valve types in the plant require very individual operational supervision and control. Revisions were complex due to the many different valve types, time consuming and associated with an extensive stock of spare parts. The operating conditions were not perfect for most of the chosen types, which resulted in short operation periods with cost intensive revision interruptions.
The analysis of the process conditions showed that two main types of valves are sufficient for all core processes. These types are compact ball valves and segment valves. The focus on these two types allowed a reduced spare parts inventory, longer service life cycles of the valves, shorter and less frequent revision interruptions which resulted in a significant cost saving throughout the production process. Especially in the case of the V-port segment ball valves, metallic and soft sealed versions were found suited for many applications.
Metal sealed versions have a considerable benefit as a control function, particularly with steam dosing systems and powder feeding into reactors. The production thus achieves greater flexibility and can manufacture a significantly wider range of products without approaching the limits of utilisation of the materials. And last but not least this flexibility allows Textilcolor to offer more specialised products from a single source and thus respond to the individual needs of the customer or to the diverse end products.
The said V–port segment ball valves are not only fitted with soft or metallic seals, but also operate as both on/off and control applications and additionally in different housing materials.
These requirements are guaranteed by the Zuercher Technik Company and the valve manufacturer JDV Control Valves. Zuercher Technik supported the user in case of any questions that arose. But how could these benefits be achieved? In a nutshell — through simple, robust and adaptable constructions, combined with the implementation of the most modern technologies, for example the HVOF coating process, as well as a simple but sophisticated seat construction.
Benefits of the HVOF–Process
A major focus of the valve manufacturer JDV Valves was on the well known 'HVOF'–process. The principle behind this procedure is a combination of plasma and detonation processes for surface coating with cobalt-chromium compounds. Depending on the requirement, specific hardnesses can be achieved up to 70 HRC — thus making the surfaces ideally suited for demanding applications like textile chemicals handling.
Apart from the required abrasion resistance against powders and steam, issues such as cavity pressure relief without ball holes and automatic readjustment of the seat are of central importance for safe and durable application. Here a spring–loaded construction also provides significant benefits.