Automatic Liquid Dosing System

What is an automatic liquid dosing system?

In soft (plasticised) PVC formulations, liquids can make up one of the largest shares of the blend. Plasticisers give cable, hose, film, tarpaulin and flooring their flexibility, while liquid stabilisers and ESBO (epoxidised soybean oil) contribute to heat stability. Getting the same amount of each liquid into the mixer in every batch directly controls the hardness, flexibility and surface quality of the product.

An automatic liquid dosing system weighs these liquids gravimetrically, by mass, according to the recipe and charges them to the hot mixer automatically. Erk PVC Makine's system is designed to weigh the liquid stabilisers needed for soft PVC precisely and to prepare the formulation fully automatically.

The problem with dosing liquids by hand

Plants that carry drums and pour by bucket usually see the same issues:

• Quantity deviations: residue left in drums, pouring by eye and reading errors give a different result every batch.
• Spills and contamination: oily liquids end up on the floor, on equipment and on other raw materials.
• Operator safety: lifting heavy drums and working on slippery floors puts operators at risk.
• Unstable quality: small differences in plasticiser content show up as variations in hardness and flexibility.

Why gravimetric liquid dosing?

Liquids can be metered by volume or flow, but the density and viscosity of plasticisers and oil-based additives change with temperature. The same volume weighs differently in winter and in summer. Gravimetric dosing weighs the liquid directly and stops feeding when the target mass is reached, so the recipe holds regardless of ambient temperature or how the liquid flows.

Which liquids can be dosed?

• Plasticisers such as DOP, DOTP and DINP
• ESBO (epoxidised soybean oil)
• Liquid Ca/Zn and Ba/Zn stabilisers
• Other liquid additives and processing aids, depending on the recipe

Storage tanks, transfer lines and the weighing arrangement for each liquid are engineered around the number of liquids you use and your plant layout.

How it works

1. Recipe selection: the operator selects the product recipe, which defines the target quantity of each liquid.
2. Weighing: each liquid is transferred from its tank into the weighing vessel, and feeding stops at the target mass.
3. Charging the mixer: the weighed liquids are added to the heating turbo mixer at the right stage of the mixing cycle. Correct timing helps the PVC resin absorb the plasticiser evenly.
4. Recording: actual weights can be logged batch by batch, giving a basis for quality control and traceability.

Working together with powder dosing

The liquid dosing system can be installed to run under one control system with the automatic powder dosing system. Resin, fillers, powder additives and liquids are then managed from the same recipe: once the powder batch is in the mixer, the liquids follow in the right sequence, and the entire formulation is prepared without operator intervention.

Typical applications

Automatic liquid dosing makes the biggest difference on soft PVC lines:

• PVC cable and cable compounds
• Garden, irrigation and transparent hoses
• Film, tarpaulin and waterproofing membranes
• Flooring and artificial leather
• Shoe sole and pellet compounding

For these recipes, mixing matters as much as weighing. Complete your line with a horizontal turbo PVC mixer fitted with a soft-PVC impeller and a granule sieve for finished pellets or compound. Erk PVC Makine does not build extruders; we supply the complete line in front of them from a single source.

Installation and support

Our systems are manufactured and tested at our factory in Ergene, Tekirdağ. We provide installation, commissioning, operator training, remote support and spare parts to customers in more than 46 countries.

Tell us which liquids you use and your batch size, and we will prepare a quotation for an automatic liquid dosing system tailored to your line.