Editorial Technical Reference

Vacuum material feeding system for plastics processing (hopper loaders and central vacuum)

Vacuum material feeding for plastics machines · venturi, single-phase and three-phase loaders, rate against distance and bulk density, central vacuum

A vacuum material feeding system draws plastic pellets, regrind or powder through hoses from a bag, octabin, dryer or silo into a receiver on top of each processing machine, using compressed-air venturi, a built-in vacuum motor or a central vacuum station. Ask three things first: what conveying rate each machine needs, over what horizontal and vertical distance and with what material, and whether each loader has its own vacuum source or shares a central one.

Vacuum hopper loaders and central vacuum conveying systems that feed plastic granules, regrind and powders to moulding and extrusion machines. General unit-load and bulk conveyor systems are covered on the Conveyor systems page; screw and belt conveyors, dryers and dosing units sold alone are outside this page.

CNFX editorial research · Sources checked October 12, 2026 · 3 sources

Size rate and distance Choose the vacuum source

Stainless vacuum receiver on a conical hopper with a flexible conveying hose, a screw feeder tube leading to an injection moulding machine that has its own small hopper loader fed by another hose — Vacuum receiver and hoses feeding resin to an injection moulding machine

Start with your task

Size rate and distancePer machine. Choose the vacuum sourceVenturi to central.

Size the conveying rate against distance and material

Shini's manual for its VL series venturi loaders, which use compressed air at about 6-8 kgf/cm² to create the conveying vacuum, lists the VL-50, VL-100 and VL-120 at 40, 60 and 80 kg/h with material hoppers of 0.5, 2.8 and 3.0 L, a maximum conveying distance of 6 m and 1.25 inch hose, and states that the rates were measured with plastic material of 0.8 kg/L bulk density and 3-5 mm diameter, lifted 2 m vertically and moved 1 m horizontally. [1]

Piovan's group page for its vacuum loaders states that the conveying rate of its standard units runs from 1 to 2,000 kg/h depending on material properties and conveying routes, with higher rates for custom solutions, and lists options including self-cleaning filters for dusty bulk materials, discharge aids, PTFE coating, loaders built as vacuum weighing units on load cells, sight glasses and bottom flap or slide gate discharge. [2]

Editorial calculation: the VL-50's 40 kg/h of 0.8 kg/L material is 40 ÷ 0.8 = 50 L/h, or about 100 fills an hour of its 0.5 L hopper; a material with lower bulk density, such as regrind, moves fewer kilograms at the same volume, so give suppliers the bulk density and the longest route rather than the machine's throughput alone. [1]

Give the supplier each machine's consumption in kg/h, the materials with bulk density, pellet size and whether regrind or powder, the source (bag, octabin, dryer, silo), horizontal and vertical distances and bends, the number of machines, compressed air or electrical supply, dust and cleanliness needs, controls and quantity.

Choose venturi, single-phase, three-phase or central vacuum

Woywod lists its hopper loaders as modular, for long conveying distances, in variants for granulates and regrind up to 120 kg/h with single-phase motors (ISP), up to 3,000 kg/h with three-phase motors (ITP), granulates, regrind and powder up to 2,800 kg/h (IPL), and a compact venturi conveyor for granules up to 130 kg/h (IVL 01). [3]

Piovan states that, on economic grounds and above all to reduce energy costs, central vacuum stations are "die optimale Lösung" (the optimal solution), built with side-channel or Roots blowers, self-cleaning separators or filters in different sizes, central vacuum with negative-pressure control and Siemens controls. [2] Shini's venturi loaders run on compressed air and list a single-phase 115/230 V ac, 50/60 Hz power supply. [1]

Editorial note: a venturi loader needs no vacuum motor but uses compressed air whenever it conveys, while motor loaders and central stations use electricity; ask each supplier for energy per kilogram conveyed at your rate and distance before comparing prices.

Receiver, vacuum source, filter, hoses and pick-up lance

The vacuum source sets rate and distance; the receiver's filter and separator sit between the material and that source.

Part	Role	Fix in the order
Receiver (hopper loader)	Collects material above the machine. [1] [2]	Volume, discharge, sight glass.
Vacuum source	Venturi, built-in motor or central station. [1] [3] [2]	Type and power.
Filter and separator	Keeps dust from the vacuum source. [2]	Self-cleaning for powders.
Hoses and pipes	Carry material; 1.25 inch on one venturi range. [1]	Diameter, route, bends.
Suction lance or pick-up	Draws from bag, octabin or dryer. [1]	Type for the source.
Controls	Sequence loaders and vacuum. [2]	Controller and alarms.

Conveying rate, distance and vacuum source data for hopper loaders

The published examples show the spread: 40 to 80 kg/h over up to 6 m for venturi loaders against up to 3,000 kg/h for three-phase units.

Field	What it means and published values	Ask the supplier for
Conveying capacity (t/h)	Examples: 40-80 kg/h venturi; up to 3,000 kg/h three-phase. [1] [3]	Rate at your distance.
Conveying distance (m)	Example: 6 m maximum on one venturi range. [1]	Route length and lift.
Conveying speed (m/s)	Air and material velocity in the line.	Design velocity.
Material temperature (°C)	Dried resin may be hot.	Limit for receiver and hose.
Operating pressure (MPa)	Compressed air 6-8 kgf/cm² for venturi. [1]	Air pressure and flow.
Power supply	Single-phase or three-phase by size. [3] [1]	Supply.
Motor power (kW)	Loader motor or central blower.	Power.
Control voltage (V DC)	Controls.	Voltage.
Ingress protection	Electrics.	Rating.
Noise level (dB(A))	Blowers and loaders.	Level.
Material of construction	Stainless hoppers on one range. [1]	Wetted materials.
Weight (kg)	Example: 4.5-7.5 kg venturi loaders. [1]	Weight on the machine.
Dimensions (L×W×H) (m)	Space above the hopper.	Height and footprint.

Send the machine, material and route data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Machines: [number; consumption kg/h]
Materials: [type; bulk density; regrind or powder]
Sources: [bag; octabin; dryer; silo]
Routes: [horizontal; vertical; bends]
Vacuum: [venturi; single-phase; three-phase; central]
Utilities: [compressed air; power]
Controls: [alarms; integration]

See manufacturer records Send an enquiry through CNFX

Buyer questions

How far can a venturi loader convey?

Shini lists a maximum of 6 m for its VL series, at 40 to 80 kg/h. [1]

What rates do vacuum loaders reach?

Woywod lists up to 120 kg/h single-phase and 3,000 kg/h three-phase; Piovan's standard units cover 1 to 2,000 kg/h. [3] [2]

Why does bulk density matter?

Shini's rates were measured with 0.8 kg/L pellets; lighter material moves fewer kilograms for the same volume (editorial note). [1]

When is a central vacuum station used?

Piovan states that, on economic grounds and above all to reduce energy costs, central vacuum stations are the optimal solution. [2]

Sources and what still needs a direct check

Sources checked 2026-10-12. Shini, Piovan and Woywod describe their own loaders and vacuum systems; Shini's figures come from a 2013 manual.

Shini — VL series venturi loader user manual, Ver. B (April 2013) ↗ Maker manual Return to text ↑
Piovan Group — Saugfördergeräte (vacuum loaders) product page, German ↗ Maker product page (German) Return to text ↑
Woywod — Hopper loaders ↗ Maker product page Return to text ↑

Still to check yourself

State rate per machine and material density.
Measure the longest route and lift.
Choose the vacuum source by energy per kg.
Specify filters for dusty material.
Verify the legal supplier and factory.