Level control filler

Level Control Filler. Plastic bottles can be manufactured clear thus for consumer appeal, they are filled to a level. This means the volume may vary but will appear to be equal due to the visually perceived common level in the containers. Flow is by gravity through a nozzle into a sealed container, whereas air equilibrates via a vent tube (Figure 8). When the rising liquid reaches the air vent port, flow stops. There is no overflow of product as in a pressure or pure vacuum filler. Aeration is at a minimum, perceived fill level is extremely accurate, and the filler is relatively simple and easy to maintain. Size consistency of the blow-molded container is critical to control, because this dictates the amount of product being sold. 

Filler surface chemistry is clearly important, although the effects vary widely according to the exact nature of the filler, polymer and surface modifier. Some of the factors that can influence toughness and are, at least in part, controlled by filler surface chemistry include the level of filler polymer interaction [40], the structure of heterophasic polymers [41], the amount of polymer degradation during compounding [42], filler dispersion [43] and polymer crystallinity arising from altered nucleation processes [44]. 

A major market which has developed for fabric fillers is for the control ot flue-gas fly ash in the utility industry. This market is primarily at the expen.se of electrostatic precipitators. Fabric filters have the inherent advantage of operating at a high level of collection efficiency tor a wide range of dust and gas conditions. 

The choice of a filler depends on the number of bottle sizes being considered for use on it. For example, if 3 1 PET bottles are to be filled, a 126 mm pitch between filling valves is required. If only small bottles up to 500 ml are to be filled, then a 70 mm pitch will suffice. This has a direct effect on the size of the filler and its footprint on the factory floor. Unless the filler bowl level is kept within tightly controlled limits, pressure head variations will affect the rate of flow into containers. Systems such as that shown in Figure 7.15 need to be employed. Wherever possible there should be minimal contact between any instrumentation and the product. Conventional float valves should be avoided and simple capacitance probes, which are easily cleanable but small and very effective, should be used. It is not uncommon in older fillers to only have one float valve. This often gives rise to filler bowl flooding, which may lead to inconsistent fill level and poor counter-pressurisation of the container pre-filling. 

The volumetric filler is also electronically controlled, ensuring an accurate dose of product to each container. For PET bottles, which creep under car-bonation pressure, there is the drawback that they will have differing fill levels over a filling cycle due to the fact that no two bottles are ever exactly identically blow-moulded. With light weighting, this problem is exacerbated. 

Two main types of volumetric filler exist. In the first type, a predetermined volume of liquid can be dosed using either a magnetic inductive volumetric flow meter or a mass flow meter. Alternatively, measuring cylinders can be used that incorporate a level probe. The product is fed to a set level in the metering cylinder, at which point the flow valve is closed off from the supply tank. A typical can filler operating at 1,500 cans of 330 ml capacity per minute will fill as per the supply contract within 2.5 ml. However, a standard deviation for a volumetric filler as low as 0.58 ml has been quoted. As with the probe filler, these fillers are fitted with electro-pneumatic valves, enabling accurate control of the... 

The objectives of the extender-filler in glue mixes are to improve the adhesive performance, to help control the mix viscosity and to conserve the phenolic and urea adhesives. These fillers and extenders serve specific needs in these glue mixes. They extend the resin solution from its original non-volatile state to lower levels, such as 26 percent resin solids in the mix. They also function as a means of maintaining the very low resin molecular weight and size molecules on the surface when they are applied to the veneer to prevent over-penetration prior to hot press pressure and temperature which gels the resin to a permanently set condition. 

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