Products · Pneumatic conveying

Pneumatic pressure conveying of bulk solids

Pressure conveying, or positive-pressure conveying, moves powders and granulates through a closed pipeline on a stream of compressed air: over long distances, from one pick-up point to several discharge points. We design each system individually, from feeding into the pipeline through to discharge, filtration and control.

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over 100 m conveying route length 1 → many one pick-up point, several discharge points high throughputs pipelines run vertically and horizontally ATEX · HACCP · GMP compliant construction

Operating principle

How pressure conveying works: air pushes the material through the pipeline

A blower produces a stream of compressed air, into which the material is fed through an airlock, usually a rotary valve or a pressure vessel feeder. The air stream carries the material along the pipeline to the discharge point, where it is separated from the air and discharged into the process. All of this takes place in a closed system, with no dust emission.

Compressed air source

A Roots blower or a side channel blower, selected to suit the material, the throughput and the length of the route. With an air cooler, an intake filter and a safety valve.

Feeding into the pipeline

The material has to be introduced into the pipeline against the pressure, so we use an airlock: a rotary valve or a pressure vessel feeder. Feeding is continuous and even.

Discharge and separation

A receiving vessel with a filter separates the material from the conveying air. Diverter valves direct the stream to the chosen destination: a silo, a mixer or a feeder.

A pneumatic pressure conveying installation with gravimetric feeders — A pressure conveying installation with gravimetric feeders

Conveying modes

Dilute phase or dense phase conveying?

Dilute phase is the standard: the material is dispersed and carried on a high-velocity air stream. It is the most versatile mode for dry, free-flowing materials. For friable or abrasive products, and for pre-blended ones, we use dense phase: the material travels in slugs, with less air and at low velocity, which keeps degradation and segregation to a minimum.

Diagram of dilute phase pneumatic conveying: particles dispersed in the air stream — Dilute phase (lean phase)Particles dispersed across the whole cross-section of the pipe and carried on a high-velocity air stream. Long distances and considerable lift heights.

Diagram of dense phase pneumatic conveying: the material travels in slugs along the bottom of the pipe — Dense phase (plug flow)The material travels in slugs, with less air and at low velocity. Suited to delicate, abrasive or heavy raw materials.

Parameter	Dilute phase lean phase	Dense phase plug flow
Air velocity	high, material in suspension	low, material flows in slugs
Product degradation	moderate	minimal
Risk of blend segregation	possible	very low
Wear on pipes and bends, and energy use	higher	much lower
Typical materials	flour, sugar, chemical powders, granulates	flakes, premixes, crystals, abrasive and heavy materials

Downloads

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

System components

What a pressure conveying installation consists of

We assemble every system from components matched to the material, the throughput and the route: from the blower, through the feeding airlock, to the receiving vessel and the controls. We integrate the system with the equipment already in place: big bag stations, feeders, mixers and packing machines.

individual design integration with the control system ATEX

BlowersRoots or side channel, with an air cooler and air filtration
Feeding airlocksrotary valves, pressure vessel feeders
Pipelinessteel or plastic, run vertically and horizontally, with large-radius bends
Valvesdiverter and non-return valves, so that one pipeline serves several discharge points
Receiving vesselswith filters and automatic cleaning, built in stainless steel
Quality controlmetal detectors, sieves, separators
Automationsequential control, integration with feeding, weighing and recipes

System selection

Pressure or vacuum conveying?

We offer both technologies and choose the one that suits the arrangement of pick-up and discharge points, the distance and the throughput, rather than the other way round. The main differences are set out below.

Parameter	Pressure positive pressure	Vacuum negative pressure
System layout	one pick-up point → several discharge points	several pick-up points → one discharge point
Route length	long, over 100 m as well	typically up to approx. 50 m
Throughput	high, continuous duty	up to approx. 10,000 kg/h, cyclic or continuous duty
Material intake	an airlock: a rotary valve or a pressure vessel feeder	a suction hopper, a lance, a big bag station
Behaviour if the system loses its seal	dust may escape to the outside	air is drawn inwards, nothing escapes

Do you need sealed pick-up from several points to a single discharge point? Take a look at our VSU vacuum conveying system.

VSU vacuum conveying

Industries and applications

Conveying bulk solids in key industries

Pneumatic pressure conveying in the food industry

Food and animal feed

Flour, sugar, cocoa, starch, feed and feed additives. Feeding silos, mixers and packing lines over long routes. FDA and HACCP construction.

Pharmaceutical and chemical

Active substances, powders, pigments, resins, detergents. A closed, hygienic conveying system, with versions for ATEX zones.

Pneumatic conveying of cement and granulates in the construction industry

Plastics and construction

PE and PP granulates, PVC, cement, lime, fly ash. Loading silos, distribution from one point to several vessels, feeding extruders.

Why INTERPROCESS

Why our solutions are worth choosing

An individual approach

We design every system around the material, the throughput and the space available on site, following a site visit.

Complete delivery

From design, through installation and commissioning, to service and spare parts.

Proven components

Only reliable, industrial solutions, with no compromises on the key sub-assemblies.

Experience across many industries

Food, chemical, pharmaceutical, plastics, construction and animal feed.

Safety and hygiene

Systems compliant with ATEX, HACCP and GMP, including for potentially explosive atmospheres.

Technical support and service

A fast service response, 24/7 where required. Audits and upgrades of existing installations.

FAQ

Frequently asked questions

When should pressure conveying be chosen instead of vacuum conveying?

Pressure conveying proves itself where material has to be sent from one pick-up point to several discharge points, over a long distance, over 100 m as well, or at a high throughput. Vacuum conveying is the better choice with several pick-up points and a single discharge point, and wherever complete containment is decisive: if a vacuum system loses its seal, the material does not escape to the outside. The two systems can also be combined into a suction and pressure arrangement.

Which materials can be conveyed under pressure?

Practically all dry, free-flowing bulk solids: flour, sugar, cocoa, starch, chemical and pharmaceutical powders, pigments, plastic granulates, cement, lime and fly ash. The limits lie with wet or strongly adhesive materials. In such cases we recommend a discussion with our application engineer.

How does the material get into the pipeline when it is under positive pressure?

Through an airlock, which separates the pressurised zone from the surroundings. Most often this is a rotary valve, which feeds the material continuously and evenly, or a pressure vessel feeder at higher throughputs. The choice of airlock depends on the material, the working pressure and how the installation is operated.

Do you build pressure conveying systems to individual order?

Yes, and it is our decisive advantage. We design the route around the infrastructure already in place, choose the blower and the airlock 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. We also carry out audits and upgrades of existing conveying installations.

Do you need a pneumatic conveying system?

Get in touch and our engineers will prepare a solution matched to your process. We also offer audits of existing installations and upgrades of older conveying systems.

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