News overview and blog about products

Stay up to date with the latest developments within Hecht Technology and the industry. In this overview, we share practical insights, technical innovations, market trends, and company news. From containment solutions and process optimization to project updates and events – here you will find relevant knowledge and current affairs for professionals in high-containment and powder handling.

Vacuum technology in the process industry

Moving powders through a plant looks simple, but in practice it is a source of dust, product loss, segregation and physical strain. Vacuum transport solves these problems by moving powder in a closed, dust-free way using negative pressure. For engineers, buyers and QA in pharma, chemicals, food and the battery industry, vacuum technology offers a hygienic, safe and flexible way to move bulk materials through the process. HECHT designs vacuum transport systems matched to your product and layout.

How vacuum transport works

Vacuum transport moves powder through a closed pipeline using a vacuum pump that creates negative pressure at the end. The powder is drawn in at the pick-up point, carried in the air stream and separated from the air in a receiver. The air is filtered and discharged; the powder drops through a valve into the next process step.

Because the system operates under negative pressure, no dust escapes in the event of a leak — air is drawn inward instead. This makes vacuum transport inherently safer than transport under positive pressure.

The core components of a vacuum system

A reliable vacuum transport system consists of matched components.

  • Pick-up point — lance, hopper or suction nozzle that takes the powder from a bag, big bag or container
  • Transport line — smooth, earthed pipe or hose that guides the powder without loss
  • Receiver — vacuum separator in which powder and air are separated
  • Filter unit — cartridge or bag filter that removes fine dust from the exhaust air
  • Vacuum generator — pump or venturi that delivers the required negative pressure
  • Outlet valve — valve that passes the powder in metered fashion to the next step

Advantages over mechanical transport

Mechanical transport systems such as screws and conveyor belts have moving parts in contact with the product, bringing wear, cleaning and contamination issues. Vacuum transport offers structural advantages.

  • Dust-free — fully closed transport protects operators and the environment
  • Hygienic — smooth, cleanable pipes without dead spots, suitable for GMP and EHEDG
  • Flexible — pipes follow any route through the plant, including vertical runs
  • Product-friendly — controlled velocity limits particle breakage and segregation

Applications in the process industry

Vacuum transport suits a wide range of powders and processes.

  • Pharma — transport of APIs and excipients under containment, with validation to GMP
  • Chemicals — moving pigments, catalysts and additives, often in ATEX environments
  • Food — hygienic transport of milk powder, cocoa, flour and spices
  • Battery — transfer of cathode and anode powders under inert, moisture-free conditions

Containment and operator protection

For highly active substances, vacuum transport is a natural containment strategy. Because the powder is never exposed to open air, operator exposure is minimal. Combined with split butterfly valves at pick-up and discharge points, a vacuum system can meet high OEB classes.

Containment performance is verified to SMEPAC, giving you objective exposure figures. For combustible powders the system is earthed and built ATEX-compliant, optionally with nitrogen inerting.

Design factors that determine performance

The performance of a vacuum system depends on correct sizing. An undersized system clogs; an oversized system wastes energy and can damage powder.

  • Product properties — density, particle size, flowability and moisture sensitivity
  • Transport distance and height — determine the required negative pressure and air flow
  • Throughput — required capacity in kilograms per hour
  • Cycle time — continuous or batch, depending on the downstream process

HECHT determines these parameters through product analysis and, where needed, transport trials in its own test centre.

Frequently asked questions about vacuum transport

Why is vacuum transport safer than pressure transport?

Under negative pressure, air is drawn inward, not blown outward. In a leak, no dust is released, protecting operators and the environment.

What distances can vacuum transport cover?

Depending on product and system, distances of several tens of metres horizontally and vertically are achievable.

Does vacuum transport damage the product?

With correct sizing and velocity control, particle breakage is minimal; HECHT matches air velocity to breakage sensitivity.

Is vacuum transport suitable for highly active substances?

Yes, combined with split butterfly valves and SMEPAC-verified containment it suits high OEB classes.

How is the system cleaned?

Via WIP or CIP, depending on the version, so cleaning takes place without disassembly and reproducibly.

How do I choose a vacuum transport system for pharmaceutical powders?

Match the system to the OEB classification of your substance: standard vacuum conveying suits low-potency excipients (OEB 1 to 3), while high-potency APIs (OEB 4 to 6) require containment-integrated vacuum transport with split-valve or isolator connections and SMEPAC-validated performance.

Related guides

Tailored advice from HECHT

A vacuum system that fits your product starts with a thorough analysis of your powder, distance and throughput. HECHT sizes, tests and supplies vacuum transport that is dust-free, hygienic and safe, and that integrates seamlessly with your dosing and filling systems. Contact us for a transport analysis and a tailored system proposal.

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Handling bulk materials: systems and best practices

Bulk material handling determines the efficiency of virtually every powder processing operation. From unloading big bags to feeding reactors, every transfer is an opportunity for dust, product loss, segregation or downtime. A well-designed handling system is the difference between a smooth, safe production line and a chain full of bottlenecks. For engineers, buyers and QA in pharma, chemicals, food and the battery industry, HECHT delivers integrated bulk material handling that is dust-free, hygienic and reliable.

What does bulk material handling cover?

Bulk material handling is the entirety of systems that receive, store, transport, dose and discharge powders and granulates within a production process. It goes beyond individual machines: it is a chain in which every link must connect to the next.

A typical chain begins with the receipt of raw materials in bags, big bags or bulk trucks, and ends with feeding a mixer, reactor or packaging line. The challenge lies in the transfer points, where most problems arise.

The links in the handling chain

Each link has its own function and its own risks.

  • Receipt and unloading — big bag discharge stations, sack tipping stations and discharge chutes with dust extraction
  • Storage — silos, hoppers and IBCs with level monitoring and discharge promotion
  • Transport — vacuum or mechanical transport between process steps
  • Dosing — gravimetric or volumetric metering into the process
  • Discharge and filling — containment filling heads into containers or packaging

Dust-free and closed design

Open transfer points are the largest source of dust and product loss in a handling chain. A closed design addresses this at every link, not just the most visible one.

  • Closed discharge stations — big bags are emptied dust-free with sealed connections
  • Extracted discharge points — displaced air is captured and filtered
  • Closed transport — vacuum transport avoids exposure between process steps
  • Containment discharge — filling heads close the chain dust-free

This protects operators, prevents cross-contamination and reduces raw material loss that hits margins directly.

Flow and preventing blockages

A handling system is only as reliable as its worst flow point. Powders with poor flow properties form bridges and ratholes in hoppers, leading to downtime. HECHT designs for guaranteed flow.

  • Mass-flow hoppers — geometry that guarantees first-in-first-out flow
  • Discharge promotion — vibrating bottoms, aeration or mechanical aids against bridging
  • Segregation prevention — controlled discharge and transport to avoid separation of fractions

Hygiene, GMP and EHEDG

In pharma and food, hygiene is as critical as flow. Product residue in dead spots poses a contamination risk during product changeovers and complicates validation. HECHT supplies handling components with polished, crevice-free surfaces to GMP and EHEDG standards.

Cleaning via WIP or CIP enables thorough cleaning without disassembly, shortening downtime between batches and delivering reproducible results. This is essential for validated production.

Safety: ATEX and operator protection

Many bulk materials are combustible or highly active, so safety must be embedded in the design. For combustible powders the entire chain is earthed and built ATEX-compliant, with explosion protection where needed. For highly active substances, containment by OEB class provides operator protection, verified via SMEPAC.

An integrated approach prevents safety from becoming a patchwork of separate solutions: one system, one safety concept.

Frequently asked questions about bulk material handling

Where do most problems in a handling chain arise?

At the transfer points between links, where dust, segregation and blockages converge. An integrated design targets these points specifically.

How is bridging in hoppers prevented?

With mass-flow geometry and discharge promotion such as vibrating bottoms or aeration, matched to the flow properties of the product.

Is bulk material handling suitable for highly active substances?

Yes, with containment by OEB class and SMEPAC verification, the chain provides operator protection to high levels.

Can HECHT upgrade an existing line?

Yes, HECHT analyses your existing chain and replaces or integrates links to reduce dust, loss and downtime.

What does a closed handling chain deliver financially?

Lower raw material loss, less downtime, faster product changeovers and lower safety costs, reducing total cost of ownership.

Related guides

Tailored advice from HECHT

Bulk material handling is not a sum of separate machines but a chain that must work as a whole. HECHT analyses your full process, identifies the bottlenecks and delivers an integrated system that is dust-free, hygienic and safe. Contact us for a process analysis and a handling concept tailored to your production.

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Pressure vessels in powder processing

Pressure vessels are an indispensable part of many powder processing operations, particularly in pneumatic transport under positive pressure. A pressure vessel stores powder and then pushes it with compressed air through a pipeline to its destination. For engineers, buyers and QA in pharma, chemicals, food and the battery industry, pressure vessels are a reliable way to move powders over greater distances. At the same time, strict requirements apply to design, safety and certification. HECHT supplies pressure vessels that meet these requirements and integrate with your process.

What is a pressure vessel and how does it work?

A pressure vessel, also called a sender vessel or transmitter, is a closed reservoir that receives powder and discharges it under positive pressure. The operating principle is cyclical: the vessel is filled, sealed, pressurised with compressed air, and emptied as the powder is pushed through the transport line.

Unlike vacuum transport, which operates under negative pressure, a pressure vessel uses positive pressure. This makes it particularly suitable for long transport distances and high throughputs, because the available pressure is greater than under vacuum.

Applications of pressure vessels

Pressure vessels are used where distance, capacity or product properties call for positive-pressure transport.

  • Long distances — transport over tens to hundreds of metres, where vacuum falls short
  • High throughput — large quantities of powder per cycle, suitable for continuous production
  • Dense phase transport — slow, product-friendly transport with minimal particle breakage
  • Abrasive powders — controlled velocity limits pipe wear

In the battery industry and chemicals, pressure vessels are often used to move large volumes under inert conditions.

Dense phase versus dilute phase transport

A pressure vessel can convey powder through the line in two ways, with major consequences for product integrity and wear.

  • Dilute phase — high air velocity, powder suspended in the air stream, suitable for free-flowing, non-friable products
  • Dense phase — low air velocity, powder moves in plugs, product-friendly with minimal breakage, ideal for friable or abrasive powders

The choice determines the sizing of vessel, pipeline and compressed air supply. HECHT advises based on your product properties.

Safety and certification

A pressure vessel falls under the European Pressure Equipment Directive (PED, 2014/68/EU). This sets requirements for design, material selection, manufacture and inspection. An uncertified pressure vessel is a safety risk and not permitted in a professional installation.

  • PED compliance — design and manufacture to the pressure equipment directive
  • Overpressure protection — safety valves that prevent inadmissible pressure
  • Material certification — traceable materials with certificates for process suitability
  • Periodic inspection — re-inspection in accordance with applicable regulations

HECHT supplies pressure vessels with the required certification and documentation for your safety file.

Containment, hygiene and ATEX

Pressure vessels in pharma and food must meet hygiene and containment requirements alongside pressure ones. HECHT designs pressure vessels with polished, cleanable surfaces to GMP and EHEDG, with WIP or CIP where validated cleaning is required.

For combustible powders the pressure vessel is earthed and built ATEX-compliant. With reactive substances, as in the battery industry, nitrogen inerting can be applied to prevent explosion and unwanted reactions.

Sizing and process integration

The performance of a pressure vessel depends on correct matching of vessel volume, cycle time, pipe diameter and compressed air supply. An undersized system fails to achieve throughput; an oversized system wastes compressed air.

HECHT determines these parameters through product analysis and transport trials, and integrates the pressure vessel into the broader handling chain with dosing, filling and storage systems. The vessel thus functions not as a standalone component but as part of a coherent whole.

More about pressure vessels: in-depth articles

Want to read more about a specific topic? Below you will find all our articles on pressure vessels.

Frequently asked questions about pressure vessels

What is the difference between a pressure vessel and vacuum transport?

A pressure vessel operates under positive pressure and suits long distances and high throughput; vacuum transport operates under negative pressure and is inherently dust-safer in a leak.

When do I choose dense phase transport?

For friable or abrasive powders, where low velocity minimises particle breakage and pipe wear.

Must a pressure vessel be certified?

Yes, a pressure vessel falls under the PED directive and requires compliant design, manufacture and inspection.

Are pressure vessels suitable for pharma?

Yes, in GMP- and EHEDG-compliant versions with cleanable surfaces and optional WIP or CIP.

Can a pressure vessel operate under inert atmosphere?

Yes, with nitrogen inerting for reactive or combustible powders, relevant in chemicals and battery.

Related guides

Tailored advice from HECHT

A pressure vessel that fits your process requires correct sizing, the right transport phase and complete certification. HECHT analyses your distance, throughput and product properties and delivers a PED-compliant pressure vessel that is safe, hygienic and integrated into your handling chain. Contact us for a transport analysis and a tailored pressure vessel concept.

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Homogenizers for powders

A homogeneous end product is, in many industries, not a luxury but a requirement. Whether it concerns a pharmaceutical formulation, a food product, a coating or a battery slurry, the consistency of the mix composition determines the quality. Homogenisers ensure that components are evenly distributed down to micro or nano scale. For engineers, buyers and QA in pharma, chemicals, food and the battery industry, HECHT delivers homogenisation solutions that are reproducible, hygienic and safe.

What does a homogeniser do?

A homogeniser reduces and distributes particles or droplets in a medium so that a uniform, stable composition results. The device applies intensive mechanical forces — shear, pressure, impact and cavitation — to break agglomerates and mix phases evenly.

The aim is a product in which no measurable differences in composition exist between different samples. This is essential for both product quality and process reproducibility.

Operating principles of homogenisation

Homogenisers work according to various physical principles, each suited to different applications.

  • Shear — high velocity differences between rotor and stator break particles and droplets apart
  • High pressure — the medium is forced through a narrow gap, where pressure and cavitation reduce particle size
  • Impact — particles collide with surfaces or each other, breaking up agglomerates
  • Cavitation — imploding vapour bubbles deliver locally intense energy for particle reduction

The combination of these forces determines the fineness and uniformity of the end result.

Types of homogenisers

Various constructions exist, matched to product and desired result.

  • Rotor-stator homogenisers — a fast-rotating rotor in a fixed stator, versatile for mixing and dispersing
  • High-pressure homogenisers — for very fine emulsions and suspensions down to nano scale
  • Inline homogenisers — integrated into a continuous process flow, suitable for high throughput
  • Batch homogenisers — for processing metered quantities in a vessel

HECHT advises the type that fits your viscosity, particle-size requirement and production format.

Applications by industry

Homogenisation is broadly applicable, each time with different goals.

  • Pharma — uniform distribution of APIs in suspensions and emulsions, critical for dosing and efficacy
  • Food — stable emulsions and consistent texture in sauces, dairy and beverages
  • Chemicals — dispersion of pigments and additives into stable coatings and pastes
  • Battery — homogeneous electrode slurries, decisive for cell performance and lifetime

In the battery industry, homogenisation of slurries is a direct quality factor: inhomogeneity leads to local capacity differences and shorter lifetime.

Hygiene, GMP and cleanability

In pharma and food, a homogeniser must deliver hygiene alongside performance. Product residue in dead spots poses a contamination risk and complicates validation. HECHT supplies homogenisers with polished, crevice-free surfaces to GMP and EHEDG.

Cleaning via WIP or CIP enables validated cleaning without disassembly, shortening downtime between batches and delivering reproducible results. For validated production this is a hard requirement.

Safety: ATEX and containment

Many homogenisation processes handle combustible solvents or powders, or highly active substances. Safety must therefore be embedded in the design. For combustible media the homogeniser is earthed and built ATEX-compliant, with inerting where needed.

For highly active substances, homogenisation is integrated into a closed, containment-compliant system, verified to SMEPAC. Operator protection thus remains assured, even under intensive mechanical processing of the medium.

Frequently asked questions about homogenisers

What is the difference between mixing and homogenising?

Mixing distributes components coarsely; homogenising reduces particles and droplets to a uniform, stable composition at micro or nano scale.

Which type of homogeniser fits my product?

That depends on viscosity, desired particle size and whether you produce in batch or continuously; HECHT advises based on your product properties.

Is homogenisation suitable for battery slurries?

Yes, homogeneous electrode slurries are crucial for cell performance; HECHT delivers solutions tailored to this application.

Can a homogeniser be cleaned in a validated way?

Yes, with GMP- and EHEDG-compliant construction and WIP or CIP for cleaning without disassembly.

Are homogenisers available ATEX-compliant?

Yes, in earthed, zone-certified versions with optional inerting for combustible media.

Related guides

Tailored advice from HECHT

The right homogeniser depends on your product, particle-size requirement, production format and safety and hygiene requirements. HECHT analyses your process and delivers a homogenisation solution that is reproducible, hygienic and safe, integrated into your handling chain. Contact us for a process analysis and a tailored homogeniser concept.

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Industrial filtration

Industrial filtration separates solid particles from gas or air streams and is indispensable in every form of powder processing. For manufacturers in pharma, chemical, food and the battery industry, the filtration strategy determines whether a process runs dust-free, safe and GMP-compliant. HECHT designs filtration solutions that combine operator protection, product retention and process efficiency. This page explains the available techniques, how to select a filter, and what to consider regarding OEB bands, ATEX and hygienic design.

Why filtration is critical in powder processing

Every transfer, conveying step or dosing operation releases fine dust. That dust poses three risks at once: operator exposure, cross-contamination of product and explosion hazard with combustible powders. Effective filtration captures particles before they spread, keeps the working environment clean and protects downstream equipment from wear.

Correct filtration also lowers your OPEX. Less dust loss means higher yield, less cleaning and longer service life for pumps and fans.

Key filtration techniques

The choice depends on particle size, flow rate, dust load and the required separation efficiency.

  • Cartridge filters — compact, high filter area per volume, ideal for fine dust and continuous operation
  • Bag filters — robust at high dust loads and coarser particles, easy to maintain
  • HEPA/ULPA filters — for critical separation up to 99.995%, essential in pharma and cleanrooms
  • Cyclones — pre-separation of the coarse fraction, reducing the load on the main filter
  • Sintered lamellas and metal filters — for high temperatures, aggressive media and cleanable applications

Cleaning: jet-pulse and mechanical

A filter inevitably becomes saturated. Cleaning during operation determines continuity. Jet-pulse cleaning uses a short blast of compressed air to release the filter cake from the medium, so the process need not stop. For containment applications, bag-in-bag-out (BIBO) designs let you replace the filter without exposure. Differential pressure monitoring tracks saturation and signals the right moment to clean or replace.

Filtration and OEB bands

For active pharmaceutical ingredients (APIs), the OEB band is decisive. The higher the OEB band, the lower the permitted exposure and the stricter the requirements for filtration and containment.

  • OEB 1–2 — standard dust extraction with cartridge or bag filter often suffices
  • OEB 3–4 — closed systems with HEPA final filtration and safe filter replacement
  • OEB 5 — isolator technology, dual HEPA filtration and validated BIBO procedures

ATEX and explosion safety

Many powders are combustible. As soon as a dust-air mixture is ignitable, the installation falls under the ATEX directive. Filtration systems must then be designed with explosion-pressure-resistant housings, pressure relief, spark detection or an ignition-source-free design. HECHT supplies ATEX-compliant filter units with the correct zoning and documentation.

Hygienic design: GMP and EHEDG

In pharma and food, cleanability matters as much as separation. Filtration components built to GMP and EHEDG guidelines have smooth surfaces, no dead zones and are CIP/WIP-cleanable. Stainless steel 316L, FDA-compliant seals and validated cleaning procedures prevent cross-contamination between batches.

Filter selection in practice

Good selection starts with process data: which powder, which particle size distribution, which flow rate and which separation efficiency. From there you define the filter class, the cleaning principle and the containment requirements. HECHT calculates the filter area based on the permitted filtration velocity, so you neither over- nor under-dimension.

Frequently asked questions about industrial filtration

Which filter class do I need for pharmaceutical powder?

For APIs with a high OEB band, HEPA H13/H14 is the starting point, often combined with a pre-filter and validated BIBO replacement.

What is the difference between a cartridge and a bag filter?

Cartridge filters offer more area in less space and perform better with fine dust. Bag filters are more robust at high dust loads and coarser particles.

How often must I replace filters?

That depends on dust load and cleaning principle. With jet-pulse cleaning filters last longer; differential pressure measurement indicates the right replacement moment.

Is my process subject to ATEX?

As soon as a combustible dust-air mixture can form, ATEX applies. A dust explosion analysis determines the zoning and the required protection.

Can I combine filtration with existing equipment?

Yes. HECHT integrates filtration into existing conveying, dosing and filling lines, including the correct containment connections.

Related guides

Tailored advice from HECHT

Want to know which filtration solution suits your powder, OEB band and process? HECHT's specialists analyse your situation and design a system that protects operators, retains product and complies with GMP and ATEX. Contact us for a no-obligation consultation.

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Lifters and handling systems for powders: the complete guide

Lifting systems determine whether your operators work safely and ergonomically with drums, big bags and containers, or whether you risk back and shoulder injuries, product loss and downtime. In pharmaceutical, chemical, food and battery production, staff lift loads every day that far exceed the ergonomic limit without assistance. This pillar shows how HECHT lifters automate powder and drum handling, which safety standards apply and how to combine ergonomics with containment.

Why lifting systems are indispensable

A drum of powder easily weighs 50 to 200 kg, a big bag 500 to 1000 kg. Tilting, lifting or emptying by hand is physically demanding and error-prone. Lifting systems take over that load, position the product accurately above a discharge point and prevent spillage. The result: less absenteeism, higher throughput and a reproducible process that does not depend on the physical strength of the operator.

Types of lifters for powder and drum handling

The right lifter depends on your load type, height and process step.

  • Drum lifters: lift, tilt and empty drums in a controlled way above a mixer or hopper.
  • Big bag lifters: hoist and position big bags for dust-free emptying, often with a discharge station.
  • Container and IBC lifters: dock to IBCs for charging process installations at height.
  • Mobile lift tables and column lifters: bring products to working height and bridge level differences in the line.
  • Vacuum lifters: lift sacks and packages without mechanical clamping force, ideal for varying formats.

Ergonomics as a design principle

Ergonomics is not a side issue but a design requirement. Good lifting systems bring the discharge point to the correct working height, eliminate reaching and bending and let the operator steer with minimal force. Match the operating height, tilt angle and speed to the task. A lifter that follows ergonomic guidelines measurably lowers the risk of musculoskeletal complaints and keeps your people deployable longer.

Integration with containment and dust-free working

Lifting and containment belong together. For active or hazardous powders you couple the lifter to a dust-free discharge, for example via a liner, a docking station or a split butterfly valve. This prevents the lifting moment itself from causing dust emission. Combine the lifter with a closed transfer to secure operator protection and ergonomics in a single action.

Safety, ATEX and standards

Lifting systems fall under strict safety rules. In zones with explosive dust the lifter must be ATEX-compliant, with spark-free design and correct grounding. The Machinery Directive and requirements for safe loading, emergency stop and fall protection also apply.

  • ATEX: spark-free, certified design for dust explosion hazard zones.
  • Machinery Directive: CE conformity, risk assessment and safe operation.
  • Load safety: validated maximum working load, overload protection and stable pick-up.
  • GMP/EHEDG: hygienic design and cleanable surfaces for pharma and food.

Material and hygienic design

In pharma and food the hygienic design determines suitability. Choose stainless steel 316L, crevice-free welds and surfaces that comply with EHEDG and GMP. This prevents product build-up, eases cleaning and keeps cross-contamination out. For corrosive chemicals you select materials resistant to the specific medium.

Return on investment and total cost of ownership

For procurement, more counts than the purchase price. Factor in the saving on absenteeism, the higher throughput and the lower product loss from spillage. A lifting system that speeds up changeover and eliminates manual steps often pays for itself within a few years. Moreover, automating handling lowers the risk of costly process errors and recalls.

Frequently asked questions about lifting systems

What load can a drum lifter handle?

That depends on the configuration, but standard drum lifters handle drums up to around 200 kg; heavier configurations are available to specification.

Are lifting systems suitable for ATEX zones?

Yes, provided you choose an ATEX-certified, spark-free design with correct grounding for zones with explosive dust.

How do I combine lifting with dust-free working?

By coupling the lifter to a closed discharge via a liner, docking station or split butterfly valve, so the lifting moment causes no dust emission.

Do lifters comply with GMP and EHEDG?

HECHT lifters are available in stainless steel 316L with crevice-free, hygienic design that meets GMP and EHEDG for pharma and food.

What does a lifting system deliver?

Less absenteeism through ergonomics, higher throughput, less product loss and a reproducible process, lowering total cost of ownership.

Related guides

Tailored advice from HECHT

Want to know which lifting system fits your load type, working height and containment requirements? HECHT engineers lifters that combine ergonomics, safety and dust-free working. Request a no-obligation consultation and receive a proposal tailored to your line.

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Screw conveying for powders

Screw conveying is one of the most reliable methods for moving powders and bulk materials in a controlled way. A rotating screw inside a closed trough or tube pushes the product from inlet to outlet at a constant, dosable rate. For engineers, buyers and QA in pharma, chemical, food and the battery industry, screw conveying offers a robust, low-dust and highly controllable solution. HECHT designs screw conveyors and dosing screws tailored to your product, capacity and hygiene requirements.

How screw conveying works

A screw conveyor consists of a helical screw shaft rotating inside a housing. The rotation moves the product axially towards the outlet. Through speed control, the screw acts as both a conveyor and a precise dosing device. This makes screw conveying ideal for processes that require a constant, adjustable mass flow.

Because the product is fully enclosed, dust emission stays minimal and the working environment remains clean and safe.

Types of screw conveyors

The right design depends on product, capacity and layout.

  • Trough screw — open or closed trough, suited to larger volumes and horizontal transport
  • Tube screw — fully enclosed tube, dust-tight and suitable for inclined transport
  • Dosing screw — short, precise screw for gravimetric or volumetric dosing
  • Shaftless screw — for sticky or fibrous products without a central shaft
  • Vertical screw — for conveying powders upward in compact layouts

Precise dosing with screw technology

Screw conveying excels at dosing. Coupling the rotation speed to a weighing system creates a gravimetric dosing screw that holds the mass flow within tight tolerances. This is critical for recipe formulation, continuous production and filling of critical ingredients.

  • Volumetric dosing — constant speed delivers a fixed volume per revolution
  • Gravimetric dosing — feedback from weighing corrects density variations
  • Loss-in-weight — continuous weighing of the supply hopper for maximum accuracy

Product-friendly conveying

Not every powder tolerates the same handling. Break-sensitive granules, sticky substances and segregation-prone mixtures call for an adapted screw design. The pitch, profile and speed of the screw determine how gently the product is moved. HECHT matches the geometry to the break sensitivity and flow properties of your product.

Containment and operator protection

For highly active powders, a closed screw system is an effective containment strategy. Combined with split-butterfly valves at inlet and outlet, the product stays isolated from the environment and operator exposure is limited. Depending on the OEB band, seals, bearings and feed-throughs are validated for leak-tightness, verified to SMEPAC.

Hygienic design: GMP and EHEDG

In pharma and food, a screw conveyor must be fully cleanable. GMP and EHEDG-compliant designs have polished surfaces (Ra ≤ 0.8 µm), no dead zones and disassembly-free CIP/WIP cleaning. Stainless steel 316L and FDA-compliant seals prevent cross-contamination between batches and product changeovers.

ATEX and safety

For combustible powders, the screw conveyor must be ATEX-compliant. Earthing, spark-free bearings, temperature monitoring and correct zoning prevent ignition. For oxygen-sensitive products such as battery powders, the system can be run inert with nitrogen.

Frequently asked questions about screw conveying

What is the difference between a conveying screw and a dosing screw?

A conveying screw moves large volumes; a dosing screw is optimised for accuracy and delivers a controlled mass flow.

What accuracy does a gravimetric dosing screw achieve?

With loss-in-weight weighing, accuracies within a fraction of a percent are achievable, depending on product and capacity.

Is screw conveying suitable for sticky products?

Yes, with a shaftless screw or an adapted pitch; HECHT selects the geometry based on the flow properties.

Can a screw conveyor operate dust-free?

A closed tube screw with the right seals operates virtually dust-free and is suitable for containment up to high OEB bands.

How is a screw conveyor cleaned?

Via CIP or WIP, or for fast product changeovers through an easily disassembled design, depending on your hygiene requirements.

Related guides

Tailored advice from HECHT

A screw conveyor that suits your product starts with an analysis of your powder, capacity and dosing requirement. HECHT designs, tests and supplies screw conveying that is reliable, low-dust and hygienic, and integrates seamlessly with your dosing and filling systems. Contact us for a conveying analysis and a tailored proposal.

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Powder transport: methods and systems for powders

Powder transport is the artery of every production line that works with bulk solids. How you move powders between dumping, mixing, dosing and packaging determines your throughput, product quality and dust emission. For pharma, chemical, food and the battery industry, the choice between pneumatic and mechanical transport is a strategic decision. This pillar explains which transport principles fit when, how to secure containment and ATEX, and where the value lies for process and cost.

The role of powder transport in your process

Transport connects all process steps. A well-chosen system moves powder in a closed manner, without segregation, product degradation or dust loss. The wrong system causes blockages, quality loss and exposure. Because transport is often the throughput bottleneck, the right choice directly delivers returns in capacity and reliability.

Pneumatic versus mechanical transport

The two main principles differ fundamentally in how they move powder.

  • Pneumatic transport: moves powder via an air stream through closed pipes, ideal for dust-free, hygienic and flexible routing over distance and height.
  • Dilute phase: high air velocity, suitable for non-friable, free-flowing powders.
  • Dense phase: low velocity, high density, ideal for friable, abrasive or segregation-sensitive products.
  • Mechanical transport: screw conveyors, trough chains and elevators for short, robust routes with high capacity.
  • Vacuum transport: closed and dust-free, popular in pharma for low to medium flow rates and easy cleaning.

Product characteristics drive the choice

The powder dictates the system. Particle size, density, moisture content, abrasiveness, friability and flow behaviour determine whether pneumatic or mechanical transport fits and in which phase. Hygroscopic or friable powders call for dense phase or vacuum transport to prevent degradation and segregation. Abrasive materials such as battery powders place extra demands on wear-resistant piping and low velocities.

Containment and dust-free transport

Closed transport is the simplest route to containment. A well-sealed pneumatic or vacuum system keeps powder entirely inside the pipe, so operators are not exposed and the room stays clean. For active pharmaceutical ingredients you couple transport to dust-free loading and discharge points via liners, docking stations or split butterfly valves. This keeps the whole chain, from source to destination, closed.

ATEX and explosion safety

Many powders form an explosive dust/air mixture. Transport through pipes also generates static charge. ATEX-compliant design is therefore not an option but a requirement.

  • Zone classification: match the design to the dust explosion zone inside and outside the installation.
  • Grounding: ensure grounding of all conductive parts to prevent spark formation.
  • Explosion protection: where needed, apply pressure relief, suppression or isolation.
  • Inert transport: use nitrogen to keep the oxygen concentration below the limit.

Hygiene, GMP and cleaning

In pharma and food, cleanability determines suitability. Choose stainless steel 316L, crevice-free construction and surfaces that comply with GMP and EHEDG. Vacuum transport is favoured because it is dismountable and easy to clean, supporting CIP or fast changeover. Secure batch separation and traceability to rule out cross-contamination.

Capacity, energy and total cost of ownership

Procurement weighs throughput against energy consumption and maintenance. Pneumatic transport is flexible but more energy-intensive; mechanical transport is efficient over short distances but less flexible in routing. Calculate the full picture: investment, energy, wear, cleaning and downtime. A system matched to your product and flow rate prevents blockages and recovers quickly, lowering total cost of ownership.

Frequently asked questions about powder transport

When do I choose pneumatic and when mechanical transport?

Pneumatic transport suits distance, height difference and dust-free requirements; mechanical transport suits short, robust routes with high capacity.

What is the difference between dilute and dense phase?

Dilute phase uses high air velocity for free-flowing powders; dense phase uses low velocity for friable, abrasive or segregation-sensitive products.

How do I keep powder transport dust-free?

With a closed pneumatic or vacuum system and dust-free loading and discharge points via liners, docking stations or split butterfly valves.

Is ATEX always necessary?

For most organic and metal powders, yes. You assess the dust explosion properties and apply zone classification, grounding and explosion protection.

Which transport suits battery powders?

Abrasive battery powders require low velocities, wear-resistant piping and often inert transport to limit degradation and explosion risk.

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Tailored advice from HECHT

Want to know which transport principle fits your powder, flow rate and layout? HECHT engineers closed transport systems that combine containment, ATEX and throughput. Request a no-obligation consultation and receive a proposal tailored to your process.

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Vacuum deaerators for powders

When powders are filled, poured or conveyed, they entrain air. That trapped air makes the product fluffy, unstable and hard to dose — and causes dust, overflowing packs and weight deviations. A vacuum deaerator removes that air under negative pressure, so the powder becomes compact, stable and reliably processable. For engineers, buyers and QA in pharma, chemical, food and the battery industry, deaeration is the key to consistent fill density and reliable dosing. HECHT designs vacuum deaerators tuned precisely to your product and process.

What a vacuum deaerator does

A vacuum deaerator extracts the air trapped between powder particles. The powder passes through a vacuum chamber or a perforated surface surrounded by negative pressure, drawing off the air while a filter retains the powder. The result is a deaerated, more compact product with a higher and more consistent bulk density.

This solves a persistent problem: fluffy powder that settles over time, leaving packs underweight or doses inconsistent.

Why deaeration matters

Trapped air causes a series of process problems that deaeration directly addresses.

  • Consistent fill density — deaerated powder fills reproducibly, without after-settling
  • Accurate dosing — a stable bulk density makes volumetric dosing reliable
  • Less dust — compact powder generates less dust during transfer and filling
  • More compact packaging — more product per pack volume, lower transport cost
  • Better flow properties — deaerated powder behaves more predictably

Operation and efficiency

A vacuum deaerator's efficiency depends on residence time in the negative-pressure zone, the depth of the vacuum and the filter area. A fine, compressible powder requires a deeper vacuum and longer residence time than a coarse, granular product. HECHT dimensions the deaerator based on particle size distribution, compressibility and the required throughput, so you gain maximum density without slowing the process.

Inline deaeration in the process chain

A vacuum deaerator works best as an integrated step, not a standalone device. Placed before the filling or dosing stage, it continuously supplies deaerated powder to the filling line. Combined with screw or vacuum conveying, it forms a closed, dust-free chain from storage to packaging, in which every pack receives the same density and weight.

Containment and operator protection

Because deaeration takes place under negative pressure, no dust escapes to the environment — air is drawn inward instead. This makes the vacuum deaerator suitable for containment applications. The extracted air is cleaned through HEPA filtration before leaving the system. For highly active substances, the design is validated to the relevant OEB band and verified to SMEPAC.

Hygienic design and ATEX

In pharma and food, the deaerator is fully CIP/WIP-cleanable, with smooth 316L surfaces and no dead zones to GMP and EHEDG. For combustible powders, the system is earthed and built ATEX-compliant, with correct zoning and explosion-safe components. For oxygen-sensitive battery powders, deaeration can take place under nitrogen.

Frequently asked questions about vacuum deaerators

What problem does a vacuum deaerator solve?

It removes trapped air, making powder more compact and keeping fill density and dosing consistent, without after-settling in the pack.

For which powders is deaeration worthwhile?

Fine, compressible and fluffy powders benefit most; coarse, free-flowing products contain less trapped air.

Does deaeration slow down my process?

When correctly dimensioned, deaeration runs inline at production speed and the process need not stop.

Is a vacuum deaerator suitable for containment?

Yes. Because it works under negative pressure with HEPA filtration, it is suitable for highly active substances up to high OEB bands.

How much density gain is achievable?

That depends on the product and its compressibility; for fluffy powders, significant improvements in bulk density are possible.

In-depth articles on vacuum deaerators

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Tailored advice from HECHT

Struggling with fluffy powder, varying fill weights or dust at the filling line? HECHT's specialists analyse your product and process and dimension a vacuum deaerator that delivers consistent density, accurate dosing and a dust-free, safe working environment. Contact us for a product analysis and a tailored proposal.

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Safe powder sampling: the complete guide

Sampling is a critical but underrated risk point in powder processing. Every time you draw a sample, you open a closed process, precisely where containment is most vulnerable. For pharma, chemical, food and battery production, safe sampling means taking a representative sample without operator exposure, cross-contamination or product loss. This pillar explains how HECHT sampling systems sample safely, representatively and GMP-compliantly, and which technique fits your OEB target.

Why sampling is a risk point

QA and QC require samples for identity, content and homogeneity. But opening a drum, pipe or mixture exposes the operator to dust and breaks the closed chain. For active pharmaceutical ingredients or toxic powders that is unacceptable. Safe sampling resolves the tension between the analytical need for a sample and the requirement of a closed, protected process.

Representativeness as the first requirement

An unsafe sample is a problem; a non-representative sample is one too. The golden rule of sampling is that the sample must represent the whole batch. Take samples at the right location and depth, at multiple points and moments, and prevent segregation while drawing. A wrongly taken sample leads to incorrect release decisions, recalls or rejected batches, no matter how well the lab analyses.

Techniques for safe sampling

The right technique depends on the medium, the process step and your containment target.

  • Sample thieves/spears: draw powder at various depths from static bulk in drums or containers.
  • In-line samplers: automatically take a sample from a moving powder stream or pipe without opening the process.
  • Closed sampling systems: take samples via a sealed port, ideal for high containment.
  • Glovebox and isolator sampling: for the highest OEB classes, keeping the operator fully separated from the product.
  • Single-use samplers: disposable samplers that eliminate cross-contamination and cleaning.

Containment and OEB classes

The required containment determines the system. For low-active substances a sealed port suffices; for high-potent APIs a closed or isolated system is needed.

  • OEB 3-4: closed sampling ports with liners or sealed interfaces.
  • OEB 5 and higher: glovebox, isolator or single-use sampling with validated disconnection.
  • Validation: confirm containment performance with SMEPAC measurements to demonstrate operator protection.

GMP, cross-contamination and traceability

Under GMP, sampling must be reproducible, documented and free of cross-contamination. Single-use samplers eliminate cleaning between samples and rule out product-bearing surfaces. Secure traceability of sample, batch and time, and use contact materials that comply with USP/EU requirements. A validated sampling procedure prevents deviations during audits.

ATEX and explosion safety during sampling

Opening a powder process in an ATEX zone requires extra care. Samplers and ports must be spark-free and grounded, so static charge causes no ignition. At high explosion risk you take samples under inert gas or via a closed system that limits oxygen ingress. Match the design to the zone classification of the installation.

Integration into the process flow

Sampling works best as a fixed part of the process, not as a separate action. Place sampling ports at logical points: after mixing for homogeneity, at receipt for identity and at discharge for release. Couple the sampler to your existing docking and liner interface, so sampling does not break the closed chain but fits into it.

Frequently asked questions about sampling

How do I take a representative powder sample?

By sampling at multiple points, depths and moments and preventing segregation while drawing, so the sample represents the whole batch.

Which sampling technique suits high-potent substances?

For OEB 5 and higher you use glovebox, isolator or single-use sampling with validated disconnection to rule out operator exposure.

How do I prevent cross-contamination during sampling?

With single-use samplers or validated cleaning, per-sample traceability and contact materials that comply with GMP and USP/EU.

Is sampling possible in an ATEX zone?

Yes, provided you use spark-free, grounded samplers and at high risk work under inert gas or via a closed system.

Can I sample without opening the process?

Yes, with in-line or closed sampling systems that sample via a sealed port without breaking the closed chain.

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Tailored advice from HECHT

Want to know which sampling system samples representatively, safely and GMP-compliantly at your OEB target? HECHT engineers closed sampling solutions that combine containment and representativeness. Request a no-obligation consultation and receive a proposal tailored to your process.

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Filling systems for powders

Filling is the final, critical step in powder processing: this is where the product is transferred into bags, drums, big bags or containers at the right weight and without dust. A good filling system combines accuracy, speed, hygiene and operator protection. For engineers, buyers and QA in pharma, chemical, food and the battery industry, the filling strategy determines product quality, throughput and the safety of the working environment. HECHT designs filling systems tuned to your product, packaging format and containment requirements.

What a filling system must deliver

A reliable filling system doses the correct weight, fills dust-free, protects the operator and keeps pace with production. These requirements often conflict: fast filling generates dust, accurate filling costs time. A good design balances them by aligning dosing, deaeration and containment.

The choice of system follows from the product, the packaging format and the required accuracy and capacity.

Filling formats and packaging

Each packaging format calls for its own approach.

  • Bag filling — open or valve bags, manual or (semi-)automatic, for 5–50 kg
  • Big bag (FIBC) filling — bulk packaging up to 1,000 kg and beyond, with deaeration and compaction
  • Drum filling — for powders and granules in steel or plastic drums
  • Container filling — IBCs and process containers for closed transfer
  • Bottles and small packs — accurate dosing of small quantities in pharma

Accurate dosing during filling

Fill accuracy determines whether you deliver under- or overweight — both cost money. Gravimetric filling with integrated load cells corrects during filling and holds the weight within tight tolerances. A coarse/fine dose (fast fill, then top-up) combines speed with precision. HECHT couples the dosing screw or valve to the weighing system for reproducible fill weights.

Dust-free filling and deaeration

During filling, powder displaces air, which wants to escape carrying dust. Dust-free filling requires closed fill heads, extraction at the fill point and deaeration of the pack. A vacuum deaerator before the fill head supplies compact, deaerated powder, so the pack settles less and dusts less. The result is a clean working environment and a consistent fill weight.

Containment and operator protection

For highly active powders, filling is the moment of highest exposure risk. Containment filling systems use split-butterfly valves, continuous liners or isolator technology to minimise operator exposure.

  • OEB 1–2 — local extraction and closed fill heads often suffice
  • OEB 3–4 — split-butterfly valves and continuous liner for closed transfer
  • OEB 5 — isolator or glovebox with validated, SMEPAC-verified containment

Hygienic design and ATEX

In pharma and food, fill heads and product-contact parts are fully CIP/WIP-cleanable, in 316L with smooth surfaces and no dead zones to GMP and EHEDG. For combustible powders, the filling system is earthed and built ATEX-compliant; for battery powders, filling can take place under nitrogen.

Frequently asked questions about filling systems

What fill accuracy is achievable?

With gravimetric filling and coarse/fine dosing, accuracies within a few tenths of a percent are achievable, depending on product and packaging.

How do I fill dust-free?

With closed fill heads, extraction at the fill point, pack deaeration and a vacuum deaerator that compacts the powder beforehand.

Which filling system suits highly active substances?

Depending on the OEB band: split-butterfly valves, continuous liner or isolator technology with SMEPAC verification.

Can one line handle multiple packaging formats?

Yes, with interchangeable fill heads and stations a line can handle bags, drums and big bags, depending on the design.

How fast can I fill?

Capacity depends on packaging format, dosing principle and accuracy requirement; HECHT dimensions to your required throughput.

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Tailored advice from HECHT

Looking for a filling system that fills your product accurately, dust-free and safely into your packaging? HECHT's specialists analyse your powder, packaging format and OEB band and design a filling line that combines quality, throughput and operator protection. Contact us for a filling analysis and a tailored proposal.

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Powder processing: the complete guide to processes and safety

Powder processing is a discipline of its own. Powders behave unpredictably: they dust, segregate, cake and form explosive mixtures. For pharma, chemical, food and the battery industry, controlling those properties determines whether a process runs safely, reproducibly and profitably. This pillar gives technical decision-makers an overview of the complete powder processing chain, from receipt to packaging, with an emphasis on safety, containment and GMP.

What makes powder processing so challenging

Unlike liquids, powders follow no fixed flow laws. Their behaviour depends on particle size, shape, moisture content, density and charge. The same powder can flow freely today and bridge tomorrow. That variability makes powder processing complex and explains why standard solutions often fail. Those who understand powder properties design a process that performs consistently.

The process steps in the chain

Powder processing is a sequence of operations that each carry their own risk.

  • Receipt and discharge: dumping sacks, big bags and drums, the dustiest part of the process.
  • Transport: moving pneumatically or mechanically between process steps.
  • Mixing and dosing: homogenizing and weighing accurately for reproducible quality.
  • Sieving and milling: adjusting particle size for flow and quality.
  • Sampling: sampling representatively for QA without opening the chain.
  • Packaging and discharge: controlled filling into final packaging or IBC.

Containment as the common thread

Throughout the chain runs one question: how do I keep powder in and the operator out? Containment means a closed process in which dust never leaves the product. You achieve this with liners, docking stations, split butterfly valves, closed transport and isolated sampling. Containment is not a separate component but a design philosophy that protects every transfer in the chain.

OEB classes and operator protection

The required containment depends on the toxicity of the product, expressed in OEB classes.

  • OEB 1-2: low activity, simple extraction and good ventilation often suffice.
  • OEB 3-4: moderately active, requires liners, closed transfer and well-engineered docking.
  • OEB 5 and higher: high-potent, requires isolators, endless liners or gloveboxes with validated disconnection.
  • Validation: confirm each containment step with SMEPAC measurements to demonstrate exposure.

ATEX and dust explosion safety

Almost every organic or metal powder can cause a dust explosion. Fine dust in the air plus an ignition source is enough. ATEX-compliant design controls this risk via zone classification, grounding of all conductive parts and, where needed, explosion protection or inertization with nitrogen. For battery powders and reactive chemicals this is an absolute design requirement, not an option.

GMP, hygiene and cleanability

In pharma and food the hygienic design determines whether an installation is usable. Choose stainless steel 316L, crevice-free welds and surfaces that comply with GMP and EHEDG. This prevents product build-up, eases CIP and rules out cross-contamination. Single-use components eliminate cleaning between batches and speed up changeover, a direct advantage with frequent product changes.

From components to an integrated system

The greatest value arises not in individual machines but in an integrated chain. When discharge, transport, mixing, sampling and packaging connect via a consistent containment and interface philosophy, the dust leaks at the transition points disappear. HECHT engineers that complete chain, so every transfer stays closed and the entire process runs reproducibly, safely and efficiently.

Frequently asked questions about powder processing

Why is powder processing more complex than liquid processing?

Because powders follow no fixed flow laws; their behaviour varies with particle size, moisture, density and charge, which often makes standard solutions fail.

What does containment mean in powder processing?

A closed process in which dust never leaves the product, achieved with liners, docking, split butterfly valves and closed transport and sampling.

How do I determine which OEB class I need?

Based on the toxicity and exposure limit of the product; the lower the permitted exposure, the higher the OEB class and the required containment.

Is ATEX necessary in powder processing?

For almost all organic and metal powders, yes, because fine dust forms an explosive mixture. Zone classification, grounding and explosion protection are then required.

How do I keep an installation GMP-compliant?

With stainless steel 316L, crevice-free hygienic design, cleanable surfaces per EHEDG and validated cleaning or single-use components.

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Tailored advice from HECHT

Want to make your powder processing safer, closed and reproducible? HECHT engineers the complete chain, from discharge to packaging, tailored to your OEB target, ATEX zone and GMP requirements. Request a no-obligation process consultation and receive a concrete proposal.

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