PLASTICS - STB Line Feed and Mixing Plant Systems

STB are the UK market leaders in the supply of bulk materials handling systems to the PVC industry. Our systems are proven over the last 30 years, and today are used by many of the UK's major PVC producers, blenders and converters.

The STB LineFeed System

The STB LineFeed System is a Central Bulk Handling System designed to feed a number of extruders or moulding machines from silos, daybins or IBC's. It is conceived as an intergrated system, rather than being arrived at by amalgamating a number of hopper-loader type units. Its unique design produces significant benefits compared to other systems, including:

• Improved product consistancy

• Greatly reduced lead and dust levels in plant

• Lower scrap rates

• Greater reliability and longevity

• Reduced plant maintenance and running costs

The entire system is easy to clean for fast changeover between materials, with interlocks and line purging to prevent cross-contamination and loading of the wrong material.

How does it work?

The LineFeed System is centred around the STB Vacuum Hopper. This is a substantial unit providing c.100kg buffer capacity over each machine. The STB Hopper has a numer of features which distinguish it from hopper loaders.

These include a large-area cartridge filter which reverses jets during the conveying cycle, enabling the unit to operate reliably even when conveying high volumes of powder over long distances.
It also has pneumatically actuated butterfly and ball valves in place of flap valves, ensuring reliability and long-term consistant performance. During colour changes, the entire unit can be cleaned and filter cartridges changed by one person in under 5 minutes, with no extruder down-time and only minimal scrap.
The Hoppers are sited on a continuous gantry running over the extruders. Product conveying lines run along the gantry, with a dedicated line for each material. The System is designed to purge conveying lines after every transfer to prevent line blockages and high vacuum on start up. Vacuum is provided by large central Roots-type exhausters in acoustic enclosures, each serving a group of hoppers.
Hoppers call for material as required, with the control system providing 'intelligent' queuing. A full graphics package is provided, with schematics displaying the status of every system component as well as product levels in silos and daybins.

The STB Mixing Plant

To date, STB have installed over 70 PVC Mixing Plants. The System is designed to feed PVC Resin and a number of additives from silos or big bags, and accurately weigh ingredients and dispense the batch into a high-speed mixer/cooling mixer combination.

From the cooler, the blend is sieved and conveyed to silos or daybins.
The entire System is designed to keep dust levels to an absolute minimum. The System is supplied with a sophisticated control system with full schematics and an operator interface.

The STB AntiSeg / Blending Silo System

The STB Anti-Segregation Silo is the ideal storage system for PVC blend. It's design utilises 'Organ Pipes' of varying lengths, which pull material from different layers in the silo. This minimises the effect of any segregation which can occur in PVC blend, and also has the effect of averaging out any variations between mixes.

The unit is avaliable in Stainless Steel, Aluminium and Epoxy-lined Mild Steel. It may be insulated and fitted with a dehumidifier if so required, and can be mounted on a tall structure to enable tanker outloading.