A VSU vacuum conveying installation in a production plant

VSU vacuum conveying system

Vacuum conveying of bulk solids VSU

Vacuum conveying moves powders and granules without dust, sealed inside closed pipework, with no moving parts along the route. The systems are designed individually, from the pick-up point through to discharge and controls.

Ask about a system How we select a system

up to 10,000 kg/h conveying rate 50+ m route length 38–100 mm pipe diameters, with the route running in any direction ATEX · FDA · GMP compliance of the build

Principle of operation

How vacuum conveying works: three components, one closed cycle

Material is drawn in from the pick-up point, separated from the air in the receiver and discharged by gravity into the process. The suction–discharge cycle repeats automatically, and the product stays inside a closed, sealed system throughout.

Material pick-up point

A suction hopper, a lance, a sack tip station or a big bag station. The material is aerated before it enters the pipework, which keeps the flow even.

VSU vacuum receiver

The heart of the system. It separates material from air using cartridge or bag filters with pulse-jet cleaning. A level sensor, a discharge valve and optional discharge aids.

Vacuum generator

The vacuum source, selected to suit the material, the rate and the distance: a side channel blower, a Roots blower, a vane pump or an ejector. With a secondary filter and sequential control.

The vacuum receiver’s working cycle, in three phases

The standard is cyclic operation with a discharge valve, a butterfly valve, as described below: the receiver draws material in, cuts off the vacuum and discharges a batch into the process, and the cycle repeats automatically under the supervision of a level sensor. In selected applications we fit a rotary valve instead of a butterfly valve, so that material is taken away continuously. The receiver then works without pauses for discharge, with the vacuum maintained in the chamber.

The working cycle of a VSU vacuum receiver: filling, settling, discharge with filter cleaning

Suction and filling

The generator creates the vacuum, material flows into the body of the receiver and settles to the bottom of the chamber. The air leaves through the top, through cartridge or bag filters whose number is matched to the rate, and these hold the dust back. The discharge valve stays closed, while aeration nozzles keep the material moving.

Vacuum cut-off and settling

Once the chamber is full, as signalled by the level sensor, the suction is cut off. The airflow stops, the material settles and the pressure in the receiver equalises with the surroundings, which allows the valve to be opened safely.

Discharge and filter cleaning

The valve opens and the batch of material falls by gravity into the process. At the same time a pulse of compressed air cleans the filters, while a pneumatic vibrator helps empty the cone. The receiver is ready for the next cycle.

VSU receivers

VSU vacuum receivers: types S, M and L

VSU receivers are built in stainless steel, in sizes matched to the rate and the working cycle, and in non-standard capacities where the process calls for them. Dismantling without tools makes cleaning and validation easier.

Type S

5 l

Type M

25 l

Type L

110 l

Key features

Filtrationcartridge or bag filters with automatic pulse-jet cleaning
Discharge valvebutterfly valve or rotary valve
Discharge aidsvibrator, aeration nozzles, level sensor
Materialssteel 1.4301 (AISI 304) as standard, 1.4404 (AISI 316L) optionally
Weighing versionmounted on load cells, with a weighing function for batch dosing
Surface finishstandard, or to EHEDG requirements: product-contact surfaces electropolished to a roughness of Ra < 0.8 µm
Hygieneopening on clamp rings, without tools (FDA, GMP, ATEX)

Type S · Type M · Type L non-standard capacities ATEX

Downloads

Pneumatic conveying data sheet (PDF) VSU selection questionnaire (PDF)

Conveying modes

Dilute phase or dense phase conveying?

Dilute phase is the standard: the material is carried in an air stream at roughly 15 m/s and above, depending on the material and the route. For friable or abrasive products, and for pre-blended ones, we use dense phase: conveying in plugs at 3–15 m/s, which keeps degradation and segregation of the material to a minimum.

Cross-section of the pipe in dilute phase conveying — Dilute phaseParticles are dispersed across the whole cross-section of the pipe and carried by a high-velocity air stream, above 15 m/s.

Cross-section of the pipe in dense phase conveying — Dense phaseThe material flows as a dense layer along the bottom of the pipe, forming travelling dunes. The particles move together, at low velocity.

Parametr	Dilute phase lean phase	Dense phase strand / plug flow
Air velocity	above 15 m/s	3–15 m/s
Product degradation	moderate	minimal
Risk of blend segregation	possible	very low
Wear on pipes and bends	higher	considerably lower
Typical materials	flour, sugar, chemical powders, cement	flakes, granules, premixes, crystals, tablets

Vacuum generators

Vacuum generators. We are not wedded to one technology

The type of vacuum generator decides the rate, the reach and the energy cost of the whole system. We work with all four types and choose the one that suits the material and the way the system runs — not the one we happen to stock.

A side channel blower as the vacuum generator in a vacuum conveying system

01Side channel blower

Simple, quiet and cheap to run. For compact systems and short routes: feeding feeders, mixers and packing machines.

02Roots blower

The answer for high rates and continuous operation. One generator serves several conveying lines in the plant in sequence.

A claw vacuum pump for vacuum conveying of bulk solids

03Vane / claw pump

High vacuum at low energy consumption. For long routes, dense phase conveying and sensitive products.

A multi-stage ejector mounted on a vacuum receiver

04Multi-stage ejector

No moving parts and no electrical supply. For explosive atmospheres, intermittent operation and mounting on the receiver.

System selection

Not sure which system to choose?
Fill in the selection questionnaire

The type of material, the rate required, the length of the route and the way the system will run are enough for our engineers to select the receiver, the vacuum generator and the build. We reply with a proposed configuration and a quotation.

Download the questionnaire (PDF) Send the completed form to us

Configurations

Example layouts for vacuum conveying systems

From simple single-line arrangements to systems with several pick-up and discharge points, dense phase and batch dosing. We design each one for its particular application.

Diagram: several pick-up points, one destination

01 · Several pick-up points

One conveying line serves several sources of material. The control system switches the pick-up between points according to the recipe, with no changeover of the installation and no operator involvement.

Diagram: one pick-up point, three destination feeders

02 · Several discharge points

Material from one pick-up point reaches several destinations. Diverter valves direct the stream, and one vacuum generator serves the lines in sequence, which lowers both the capital and the running cost.

03 · Dense phase

The answer for friable and abrasive products and for finished blends. The material travels in plugs at 3–15 m/s instead of being carried in an air stream. The product arrives undamaged, the blend does not segregate, and the bends wear more slowly.

04 · Batch dosing

A receiver mounted on load cells acts as a scale: it meters the ingredients of the recipe one after another and discharges the finished batch into the process. One unit handles both conveying and weighing, with no separate hopper scale.

Industries and applications

Conveying bulk solids in key industries

Vacuum conveying of bulk solids in the food industry

Food and animal feed

Flour, sugar, cocoa, milk powder, starch, premixes, feeds. Charging mixers, feeding feeders, conveying from big bags. FDA and HACCP builds.

Vacuum conveying of powders in the pharmaceutical industry

Pharmaceuticals and chemicals

Active substances (APIs), tablets, pigments, resins, plastics granules. Sealed conveying, ATEX zones, dismantling without tools for cleaning and validation.

Pneumatic conveying of granules and cement in the construction industry

Plastics and construction

PE and PP granules, PVC, cement, lime, titanium dioxide, fly ash. Discharging silos and road tankers, feeding extruders and reactors.

Gallery

Vacuum conveying installations

Click to enlarge

Type M receivers for conveying spices and dough ingredients

Vacuum generators with side channel blowers

A line conveying ingredients for jellies and custards

A Type L vacuum receiver prepared for continuous conveying of sugar

A vacuum conveying line taking freeze-dried product to a packing machine

Video

VSU vacuum conveying on film

Introductory film: how a VSU system works

Dismantling a Type L receiver without tools

Drawing material from a DSL screw feeder

Picking up material with a suction lance

Trials on your own material

Hire a VSU system before you decide

Every bulk solid behaves differently. Rather than relying on catalogue rates, we make a mobile VSU system available for trials at your own plant: on your product, along your route and in your working cycle. You can check the real rate, how the material behaves and how well the filtration works, before you decide to buy.

•trials on your material, at your plant
•a complete system: receiver, vacuum generator and pipework
•support from our engineer at commissioning and in assessing the results

Ask about hiring

Vacuum conveying trials on the customer's material, with a VSU system on hire

FAQ

Frequently asked questions

What are the advantages of vacuum conveying over mechanical conveyors?+

With no moving parts along the route, maintenance is minimal and there is no risk of contaminating the product. The material travels inside closed pipework, which keeps the process completely free of dust — decisive in the food and pharmaceutical industries and in explosive atmospheres. The pipework can run through walls and between floors, and if a vacuum system loses its seal the material does not escape. One installation can pick material up from several points and deliver it to a single destination.

Will a vacuum conveying system fit into a confined plant?+

Yes. Pipework of 38–100 mm diameter can run vertically, horizontally, through walls and floors and around existing equipment. The vacuum generator can stand in a different room from the receiver. We design every system after a site visit, taking account of the existing infrastructure and of future expansion.

Do you build vacuum conveying systems to order?+

Yes, and it is our decisive advantage. We match the receiver to the rate and the working cycle, including non-standard capacities, design the route around the obstacles that are already there, choose the vacuum generator to suit the material, and integrate the system with feeders, big bag stations, mixers and the control system. From the site visit through to commissioning and service.

Which materials can be conveyed by vacuum?+

Practically every dry bulk solid: fine powders such as flour, cocoa and titanium dioxide; granules such as PE/PP, PVC and fertilisers; friable materials such as flakes and tablets; and abrasive ones such as cement and quartz. The limits are wet or strongly sticky materials. In those cases we recommend talking to our applications engineer.

Can a vacuum conveying system dose in batches?+

Yes. A receiver mounted on load cells acts as a scale. The controller follows the increase in weight and closes the valve once the set value is reached; when the reading has settled, the batch passes by gravity into the process. The controller handles multi-ingredient recipes, weighing out the ingredients one after another before the batch is discharged.

Need a vacuum conveying system?

We will design a system around your material, your rate and your space. Audits of existing installations, upgrades, and full support from design to commissioning.

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