News overview and blog about products

Granulation: from powder to processable granulate

Granulation is the process in which fine powder particles are combined into larger, stable agglomerates (granules). The goal is to improve the processing properties of the powder: better flowability for dosing systems and tablet presses, higher bulk density for more compact storage and transport, improved compressibility for tableting, and reduced dust formation with hazardous substances. Granulation is a central step in pharmaceutical solid dosage form production and is also applied in food, chemistry and fertiliser production.

Wet granulation: the most widely used granulation technique

In wet granulation, powder particles are combined by adding a binder solution (granulation liquid). The binder (gelatine, PVP, HPMC, hydroxypropyl cellulose) forms bridges between particles that yield stable granules after drying. Wet granulation takes place in:

• High-shear mixer-granulator: intensive mixing and granulation in a single vessel; short process time (10–20 min); suitable for APIs requiring robust granulation
• Fluid bed granulator: powder is suspended in a fluidised bed while binder solution is sprayed on; gentler process; simultaneous granulation and drying
• Twin-screw granulator: continuous processing; high formulation flexibility; suitable for continuous manufacturing lines

Wet granulation is not suitable for moisture-sensitive or thermolabile APIs.

Dry granulation: for moisture-sensitive products

In dry granulation, powder particles are compressed together without adding liquid. The two most commonly used methods are:

• Roller compaction: powder is compressed between two counter-rotating rollers into compact ribbons, which are then milled into granulate. Scalable, continuous processing, broadly applicable
• Slugging: powder is first compressed into large tablets (slugs) and then milled. Less efficient than roller compaction; increasingly less used

Fluid bed technology: granulating and drying in one step

Fluid bed processors can granulate, coat and dry in the same equipment. An upward airflow keeps the material suspended while a spray nozzle applies binder or coating. Fluid bed technology offers high process flexibility but requires precise control of air volume flow, temperature and spray rate.

Selection criteria for granulation technology

• Moisture sensitivity of the API: moisture-sensitive → dry granulation or fluid bed
• Thermolability: thermolabile → low-temperature fluid bed or dry granulation
• Batch vs. continuous production: continuous production → twin-screw or roller compaction
• Desired granule properties: particle size, density, porosity
• Scale: from gram-scale lab to ton-scale production

Hecht Technology supplies bulk handling systems for granulate processing lines: contained transfer, dosing and transport of granulates for pharma and food. More information: hecht-technology.nl.

Hecht Technology: downstream processing after granulation

After granulation, the granulate often still needs to be dried and brought to the correct particle size. Hecht Technology supplies Nutsche filter dryers for drying moist granulates in a closed, GMP-compliant environment, and the Jett Mill for fine milling or adjusting the particle size distribution after granulation.

Our products

• Nutsche filter dryers
• Jett mill

Endless liner technology is one of the most effective methods for contained filling and emptying of big bags with highly potent, toxic or valuable powders. The plastic liner forms a hermetic barrier between the product and the operator — without the complexity and cost of a full isolator system. This makes endless liner systems particularly popular in the pharmaceutical industry for OEB 3–5 applications.

What is an endless liner?

An endless liner is a continuous tube of polyethylene (PE) or other suitable plastic material, wound on a roll. The liner is pulled over the filling head or discharge head of the big bag and forms a closed, dust-free tunnel between the big bag and the production installation. After use, a section of liner is cut off and disposed of — so every transfer is covered with a clean, uncontaminated liner.

Endless liner filling heads: LBK, SBK and LBK-EC

LBK (Liner Bag Connector)

The standard endless liner filling head for big bag filling. The liner is pulled over the filling head and clamped in place. The powder flows through the liner into the big bag, fully shielded from the environment. After filling, the liner is pinched shut, cut off and knotted — the big bag is then contained and sealed.

SBK (Standard Bag Connector)

A more compact version of the LBK, suitable for smaller filling heads and limited space. Same operating principle as the LBK.

LBK-EC (Easy Connect)

Version with a Quick Connect mechanism for fast, contained coupling and decoupling. The operator does not need to manually pull the liner over the filling head — the connection clicks into place. Ideal for high throughput rates or frequent big bag changeovers.

Endless liner discharge systems: SAS

The SAS (Sleeve Attachment System) is the counterpart of the filling head: it is a contained connection point at the bottom of the big bag for discharging. The liner is connected to the process installation via the SAS connection, after which the material is transferred in a contained manner. After discharge, the liner is pinched shut and cut off — no product contact for the operator.

Containment levels with endless liner

Endless liner systems typically achieve an OEL (Occupational Exposure Limit) of 1–10 µg/m³, corresponding to OEB 4 performance. For OEB 5, additional measures are needed (e.g. combination with bag-in-bag transfer or an isolator). The advantages compared to an isolator: significantly lower investment costs, less validation effort and higher flexibility during product changeovers.

Materials and compatibility

Endless liners are available in:

• LDPE (Low Density Polyethylene): standard, FDA-compatible, economical
• HDPE: higher rigidity, suitable for abrasive materials
• Antistatic PE: for explosion-sensitive materials (ATEX environments)
• Aluminium laminate: for hygroscopic or light-sensitive products

Applications in the pharmaceutical industry

Endless liner systems are used in the pharmaceutical industry for:

• Contained filling of big bags with API powder (OEB 3–4)
• Contained emptying of raw material big bags into the production line
• Intermediate transport of semi-finished products between production steps
• Clinical batches where flexibility and fast product changeover are required

Hecht Technology: custom endless liner systems

Hecht Technology supplies the complete endless liner portfolio — from standard LBK filling heads to LBK-EC Easy Connect and SAS discharge systems. All systems are available in GMP-compliant versions with documented material certificates.

View our products: LBK-EC filling head, SBK filling head, SAS discharge system, endless liner material.

Conclusion

Endless liner technology offers a cost-effective solution for contained big bag handling at OEB 3–4 level. The combination of LBK/SBK filling heads, SAS discharge systems and the right liner specification delivers a robust, flexible and GMP-compliant system for the pharmaceutical and chemical industry.

Our endless liner products

• Endless liner
• Endless liner connection system SAS
• Endless liner filling head LBK
• Endless liner filling head SBK
• LAS-MC - Liner connection system "Manual Connect"

Read also

• What is single-use technology and why is it important?
• Endless liner filling head LBK-EC Easy Connect

Not every big bag is the same. The international IBC standard (FIBC = Flexible Intermediate Bulk Container) distinguishes four types based on their electrically conductive properties. The right choice prevents static discharge — a real risk with powders in combination with flammable gases or dust explosions.

Type A: non-conductive, no protection

Type A FIBCs are made of non-conductive polypropylene (PP). They offer no protection against static discharge and may only be used when:

• The material is not flammable or explosive
• No flammable gases or liquids are present in the environment

Suitable for: non-flammable powders such as sand, gravel, sugar (in a non-explosive environment). Lowest cost.

Type B: insulating but with low breakdown voltage

Type B resembles type A but is made of materials with a breakdown voltage of <6 kV. This prevents sparks with enough energy for dust explosions, but offers no protection against corona discharge or sparks that could ignite flammable gases. Use type B only when no flammable gases or vapours are present.

Type C: conductive and grounded

Type C FIBCs are made with conductive threads woven into a grid through the PP fabric. These threads are connected to a grounding point on the discharge or filling installation. Advantages:

• Safe to use in the presence of flammable gases and vapours
• Requires correct grounding — without grounding, type C offers no protection
• Reusable provided conductivity is checked

Suitable for: flammable powders, pharmaceutical APIs, fine chemical powder. Requires a grounding protocol.

Type D: dissipative without grounding

Type D FIBCs are made of special dissipative PP fabric that discharges charge via corona discharge into the surrounding air — without grounding being required. Advantages:

• No grounding cable needed (eliminates operator error)
• Safe in flammable gas environments, provided the material in the bag is not conductive
• Higher purchase price but lower operational risk

Suitable for: situations where consistent grounding cannot be guaranteed; high-value pharmaceutical or chemical applications.

Overview: which FIBC type to choose?

Additional considerations in FIBC selection

Besides the type, the following factors also play a role in selecting the right big bag:

• SWL (Safe Working Load): standard 500–2,000 kg, choose a minimum 5:1 safety factor
• Inlet and outlet type: spout top, duffel top, fill spout bottom, discharge spout
• Liner: PE liner for moisture protection or endless liner for contained handling
• Codemax / UN certification: required for hazardous goods transport

Conclusion

The right FIBC selection is more than just choosing a bag. For flammable or pharmaceutical powders, the FIBC type determines the safety of the entire discharge process. Hecht Technology advises on the right choice and supplies discharge systems compatible with all FIBC types.

More info: Complete guide to big bag handling.

Read also

• Big bag handling: filling, emptying and transport – complete guide
• What are the benefits of using FIBCs in containment for the food industry
• What are the benefits of using FIBCs in containment for the recycling industry
• Big bag connection system LAS-EC Easy Connect

Our products

• O-rings
• Quick-connect Tri-Clamp

Why vacuum drying?

Vacuum drying removes solvents and moisture from a product at reduced pressure, which lowers the boiling point of the liquid. As a result the product dries at far lower temperatures than in an atmospheric dryer — often below 60 °C — protecting heat-sensitive active ingredients, preserving product quality and preventing oxidation. For pharmaceutical and fine-chemical powders, where thermal degradation and solvent recovery are critical, vacuum drying is frequently the only acceptable method.

Conical vacuum dryer

The conical vacuum dryer combines a heated jacketed cone with a rotating screw that gently lifts and mixes the product along the wall. The continuous, gentle agitation gives uniform drying without lumps and excellent batch-to-batch consistency. Its geometry allows near-complete discharge, easy cleaning and effective containment, which makes it a workhorse for GMP powder drying.

Double cone vacuum dryer

The double cone dryer tumbles the entire batch by rotating the vessel itself, with heat transferred through the jacketed wall. Because no internal moving parts contact the product, it is gentle on friable materials and simple to clean. It suits free-flowing products and moderate drying duties where mechanical simplicity is valued.

Horizontal vacuum dryer (paddle dryer)

In a horizontal paddle dryer, heated paddles on a central shaft turn the product over a large heated surface. The high heat-transfer area and intensive mixing deliver fast drying and high throughput, and the design copes well with pastes and sticky products that pass through a plastic phase during drying.

Flash and spray drying under vacuum

For continuous drying of pumpable feeds, spray and flash techniques disperse the product into a fine mist or a hot gas stream so that drying happens in seconds. Operating under vacuum keeps temperatures low, which is valuable for thermolabile products and for capturing solvents. These methods excel where large volumes and consistent particle properties are required.

Nutsche filter dryer

The Nutsche filter dryer combines filtration, washing and drying in a single closed vessel. The slurry is filtered, the cake is washed and then dried under vacuum with heat and agitation — all without transferring the product between machines. This one-pot approach maximises containment and yield, which is why it is a cornerstone of high-potency API manufacturing.

Technology selection: a decision framework

Choosing the right vacuum dryer depends on the starting material (slurry, cake, paste or wet powder), the solvent to be removed, heat sensitivity, required capacity, containment level and cleaning requirements. A friable, high-potency API points toward a Nutsche or conical dryer; a robust free-flowing granulate may run perfectly in a double cone. The safest route is to define these parameters first and validate the choice with drying trials.

Vacuum dryers for pharma and chemicals from Hecht Technology

Hecht Technology engineers vacuum drying systems around your product and your compliance requirements, with full attention to containment, cleanability and solvent recovery. From technology selection and testing through to installation and qualification, we deliver drying solutions that protect product quality and keep operators safe.

Conclusion

Vacuum drying delivers low-temperature, high-quality drying for sensitive powders — but only when the technology is matched to the product. Understanding the strengths of conical, double cone, paddle, spray and Nutsche dryers is the first step toward a robust, compliant drying process.

Related guides and solutions

• Industrial centrifuges
• Industrial crystallisation
• Pharmaceutical powder handling and GMP
• Containment: OEB 1 to 6
• Industrial filtration and dust extraction

Onze producten

• Verticale vacuümlintdroger
• Nutsche filterdrogers

What is an industrial centrifuge?

An industrial centrifuge separates solids from liquids — or two liquids of different density — by spinning the mixture at high speed. The centrifugal force, often thousands of times gravity, drives the denser phase outward, achieving separations that would be slow or impossible by gravity alone. In powder and chemical processing, centrifuges recover crystalline products, dewater slurries and clarify liquids, delivering a clean solid cake and a clear filtrate in a single, fast step.

Three main types: batch, tubular and continuous

Batch centrifuges

Batch (peeler and basket) centrifuges process one charge at a time. The slurry is fed into a perforated basket, the liquid passes through the filter cloth, and the retained cake is washed and then discharged. They give excellent cake washing and high purity, which makes them the standard for high-value pharmaceutical and fine-chemical crystals where product quality outweighs throughput.

Tubular centrifuges

Tubular centrifuges spin a narrow bowl at very high speed to generate extreme g-forces. They excel at clarifying liquids and separating fine or difficult solids, and at splitting two immiscible liquids. Their high separation efficiency suits low-solids, high-clarity duties such as biotech and fine chemicals.

Continuous centrifuges

Continuous machines — such as pusher and decanter centrifuges — separate solids and liquids in an uninterrupted flow. They handle high solids throughput with low operator involvement, which makes them the choice for large-volume dewatering in chemicals, food and minerals where consistent, continuous output is the priority.

Separation efficiency: what determines performance?

Performance depends on the balance between the applied g-force, the residence time and the properties of the feed — particle size, density difference, solids concentration and viscosity. Fine particles and small density differences demand higher g-forces or longer residence; high solids loads favour continuous machines. Matching these variables to the machine is what turns a specification into real, repeatable separation.

GMP requirements and pharmaceutical applications

In pharmaceutical production a centrifuge is a critical, regulated unit. It must offer crevice-free hygienic design, clean-in-place capability, contained discharge for potent compounds and full validation of cleaning and performance. Effective cake washing directly affects purity, and closed, contained operation protects both the product from contamination and the operator from exposure.

Selection guide: which type fits your process?

Choosing a centrifuge starts with the goal. For maximum purity of high-value crystals, a batch peeler centrifuge; for clarifying liquids or separating fine solids, a tubular machine; for high-volume continuous dewatering, a decanter or pusher. Feed characteristics, required cake dryness, washing needs, capacity and containment level then narrow the choice to a specific design.

Integration into your production line

A centrifuge sits between upstream crystallisation or reaction and downstream drying and handling. Integrating feed control, wash sequencing, cake discharge and data logging with the plant control system delivers consistent results and full batch traceability. Well-designed integration also protects the product between steps, for example with contained transfer into a downstream dryer.

Conclusion: centrifugal separation as process optimisation

The right centrifuge does more than separate — it sets product purity, yield and downstream drying load in one step. Selecting and integrating the correct type for your feed and your compliance requirements turns separation into genuine process optimisation. Hecht Technology engineers centrifugal separation solutions tailored to your product, your capacity and your GMP requirements.

Related guides and solutions

• Vacuum drying
• Industrial crystallisation
• Pharmaceutical powder handling and GMP
• Industrial filtration and dust extraction
• Containment: OEB 1 to 6

Our products

• Batch centrifuges
• Tubular centrifuges
• Continuous centrifuges

From bulk to small packaging: the filling process explained

Bag filling — often called bagging — is the step where bulk product is portioned into open-mouth bags, valve bags or small containers ready for shipment or downstream use. It looks simple, but it sits at the crossroads of accuracy, speed, dust control and operator safety. A filling station that under-fills gives product away; one that over-fills breaches the declared weight; and one without proper dust extraction exposes operators and the plant to airborne powder. Getting the filling step right protects margin, compliance and health at once.

Types of filling stations for bags and small packaging

Open-mouth bag fillers

Open-mouth fillers hold an open bag under a fill spout while product is metered in, then the bag is closed by stitching or heat sealing. They are flexible, handle a wide range of bag sizes and are the standard choice for powders and granulates in the 5–50 kg range.

Valve bag fillers

Valve bags are pre-formed with a self-closing valve in one corner. Product is injected through the valve and the bag seals itself once full. This design is fast, compact and clean, and is widely used for fine powders such as cement, minerals and chemicals.

Small-packaging filling stations (1–25 kg)

For retail packs and smaller industrial units, dedicated small-packaging stations combine precise weighing with gentle, low-dust filling. Accuracy matters most here because the tolerance on a 1 kg pack is far tighter in relative terms than on a 25 kg bag.

Containment filling stations for potent substances

When the product is a potent API or a hazardous powder, filling must happen without exposing the operator. Containment stations use glove boxes, split butterfly valves and integrated extraction to achieve OEB 4–5 exposure limits while still filling accurately and cleanly.

Weighing principles and accuracy

Every filling station is only as good as its weighing system. Gross weighing fills the bag on the scale; net weighing meters a pre-weighed dose and then discharges it, giving higher accuracy and speed. Load cells, a stable frame and correct calibration determine repeatability, while a two-stage bulk-then-dribble feed balances speed against precision to hit the target weight consistently.

Integration into the production line

A filling station rarely works in isolation. It is fed from silos, big-bag dischargers or mixers, and feeds into palletising, sealing and conveying. Integrating weighing data with the plant control system enables recipe control, automatic batch records and full traceability from raw material to finished pack — essential in regulated food and pharma production.

Conclusion: the filling station as a critical link

The filling station is where product value is finally packaged — and where accuracy, dust control and containment either protect or undermine everything upstream. Choosing the right type, weighing principle and level of containment for your product is a decision with direct impact on cost, compliance and safety. Hecht Technology designs filling and small-packaging stations that are accurate, contained and fully integrated into your line.

Related guides and solutions

• Dosing and weighing technology
• Big bag handling
• Containment: OEB 1 to 6
• Lifting aids and handling equipment
• Bulk handling

Our products

• SE-H bag dumping cabinet
• Filling stations for small containers

A vacuum lifter lifts products by creating negative pressure between the suction head and the surface of the load. The operator steers the direction; the system carries the full weight. That sounds simple, but selecting the right vacuum lifter for your specific application requires insight into the product, environment and cycle frequency.

Operating principle: how does a vacuum lifter work?

A vacuum lifter consists of three components: a vacuum source (pump or venturi), a suction head (pad) and a lifting system (arm, suction beam or crane). The vacuum pump generates negative pressure in the suction head. When the suction head contacts the product surface, the negative pressure holds the product in place. Release occurs via a valve that neutralises the vacuum.

The lifting force equals: F = ΔP × A, where ΔP is the pressure difference in Pa and A the contact area in m². At a vacuum of 0.6 bar and a suction head of 200 cm², the lifting force is: 0.6 × 10⁵ Pa × 0.02 m² = 1,200 N ≈ 120 kg.

Application areas: what does a vacuum lifter lift?

Vacuum lifters are suitable for all products with a smooth, non-porous surface:

• Bags and big bags: paper, PE or laminate bags of 5–50 kg; FIBC bags of 500–1,500 kg
• Cardboard boxes: retail boxes, master cases, pallet layers
• Drums and barrels: upright discharge or tilting for emptying
• Plates and panels: steel plates, glass sheets, sandwich panels in manufacturing and construction
• IBC containers: 1,000 litre intermediate containers for liquids or powders

See also the pillar page on lifting aids and lifting equipment for an overview of all lifting solutions.

Selection criteria: five questions that determine the choice

1. What is the weight and size of the load?

Determines the required lifting capacity and the size of the suction head. Vacuum lifters are available from 10 kg to 2,000 kg capacity. Larger loads require multiple suction heads or larger contact areas.

2. What is the surface of the load?

Smooth and flat (PE film, steel, glass): a standard rubber pad works excellently. Rough or textured (paper bag, cardboard): a softer foam pad or bellows-shaped suction head for better contact. Porous or textile: vacuum lifting is not possible — use a clamp lift or mechanical gripper instead.

3. Which environmental class applies?

Standard industrial use: electric vacuum pump. ATEX Zone 1 or 2 (explosion hazard): compressed-air-driven venturi system with no electricity in the hazardous zone. Cleanroom or pharma: stainless steel construction, cleanable, no oil-containing components, PTFE seals.

4. How often is lifting performed per hour?

Low frequency (1–5 lift cycles/hour): a single system with manual operation suffices. High frequency (20+ cycles/hour): a balancer system or integrated vacuum lifting arm with automatic valves for fast pick-up and release. Continuous use: industrial-grade systems with higher wear resistance and 24/7 operating hours.

5. What is the available working height and space?

Vacuum lifters are mounted on column cranes, gantry cranes, mobile arms or pallet trucks. The available overhead space and desired reach determine the lifting device type.

Safety: failsafe systems

A vacuum lifter must always be failsafe. In the event of a power outage or vacuum loss, the load must not fall. Modern systems include a vacuum reservoir (buffer) that maintains sufficient negative pressure to hold the load during a power outage. An alarm and automatic emergency stop trigger when the vacuum drops below the safe threshold. Periodic safety tests per EN 13155 (non-fixed load lifting attachments) are mandatory.

Conclusion: vacuum lifter as a productivity booster

The right vacuum lifter doubles productivity in repetitive lifting tasks, eliminates back injuries and fits seamlessly into existing production environments. Selection is bespoke: weight, surface, environment and frequency together determine the optimal system.

Hecht Technology advises on and supplies vacuum lifters for the process industry. Visit hecht-technology.nl for more information.

Our products

• Barrel lifting aid
• Pallet lifting aid

What is dust explosion risk and why is ATEX relevant to bulk handling?

Many everyday powders — flour, sugar, milk powder, metals, pharmaceuticals, plastics — are combustible. When such a dust is dispersed as a cloud in air and meets an ignition source, it can explode with destructive force. Because bulk handling constantly creates dust clouds inside conveyors, mills, mixers, filters and silos, it is one of the highest-risk activities for dust explosions. The ATEX directives (2014/34/EU for equipment and 1999/92/EC for workplaces) set the European legal framework for preventing and protecting against these explosions.

Dust explosion: the five conditions

A dust explosion needs five conditions at the same time, often shown as the explosion pentagon: combustible dust, dispersion of that dust into a cloud, sufficient oxygen, confinement, and an ignition source. Remove any one and an explosion cannot happen. This principle underlies every prevention and protection strategy: eliminate the dust cloud, control the oxygen, or remove ignition sources.

ATEX dust zones: zone 20, 21 and 22

ATEX classifies areas where combustible dust may be present into three zones. Zone 20 is where an explosive dust cloud is present continuously or for long periods — typically inside equipment such as silos, filters and mixers. Zone 21 is where a cloud is likely to occur occasionally in normal operation, for example around a filling point. Zone 22 is where a cloud is unlikely and, if it occurs, only briefly. The zone classification determines which equipment category may be installed.

Explosion-relevant dust parameters

Not all dusts are equally dangerous, and design must be based on measured parameters. Key values include Kst and Pmax (explosion violence and maximum pressure), the minimum ignition energy (MIE), the minimum ignition temperature and the lower explosion limit. These figures are determined by laboratory testing of the actual product and form the basis for correct zoning, equipment selection and protection design.

ATEX requirements for bulk handling equipment

Equipment installed in a dust zone must be certified for the corresponding ATEX category and built to avoid becoming an ignition source. That means controlling surface temperatures, preventing mechanical sparks, correct earthing to dissipate static, and appropriate ingress protection. Every component — rotary valves, filters, conveyors, level sensors — must be selected and documented for its zone.

Explosion protection: three strategies

Where prevention cannot fully exclude an explosion, protection limits its consequences. Three constructional strategies are used: explosion venting (relieving pressure safely through a rupture panel), explosion suppression (detecting the incipient explosion and injecting a suppressant within milliseconds), and explosion isolation (preventing flame and pressure from propagating through connected pipework into other equipment). These are often combined to protect a complete system.

Inerting as a primary prevention measure

The most fundamental prevention is to remove the oxygen. Inerting replaces the air inside equipment with an inert gas such as nitrogen, keeping the oxygen concentration below the limiting value at which an explosion can propagate. For high-risk metal and pharmaceutical powders, inerting turns explosion protection from damage limitation into genuine prevention. Hecht Technology designs bulk handling systems with integrated ATEX compliance — from dust testing and zoning to inerting, protection and certified equipment — so your process is safe by design.

Related guides and solutions

• Industrial filtration and dust extraction
• Pneumatic powder transport
• Silo installations and bulk storage
• Containment: OEB 1 to 6
• Bulk handling

Our products

• Single-use isolator
• Containment clip

Dozens of blog articles about mixing, but no clear winner in Google? That's the classic result of keyword cannibalisation. This page bundles everything you need to know about powder mixing — from mixing principles to technology comparison — so you can make a well-informed choice for your process.

Mixing principles: batch vs. continuous mixing

The first strategic choice in any mixing process is the process format:

Batch mixing processes a fixed quantity of powder per cycle. You load, mix, discharge and repeat. Advantages: full control per batch, easy cleaning, ideal for product changeovers and smaller volumes. Typical cycle time: 5–20 minutes depending on material and mixing intensity.

Continuous mixing feeds and discharges powder without interruption. Suitable for large-scale production of a single product. Lower labour costs per kg, but higher demands on process stability and dosing accuracy.

For pharma, food and specialty chemistry, 80% of manufacturers choose batch mixing because of traceability and GMP requirements.

Comparing mixing technologies

Not every mixer suits every powder. The key technologies:

Double Cone Blender
Operation: two cones rotate around a horizontal axis; powder tumbles under gravity.
Suitable for: free-flowing powders, low shear sensitivity, pharmaceutical bulk powders.
Mixing quality: CV < 5% achievable in 10–15 minutes.
Containment option: OEB1–OEB3 standard, OEB4–OEB5 on request with split-butterfly valves.

V-Blender (Twin Shell)
Operation: V-shaped drum with tumbling and tipping motion; intensive cross-mixing.
Suitable for: granulates, crystals, dry powders with a broad particle size distribution.
Not suitable for: liquids or cohesive powders prone to caking.
Scale range: 1 litre lab scale to 10,000 litre production scale.

Containment mixer OEB4–OEB5
For highly potent active substances (HPAPIs) with an OEL < 1 µg/m³. HECHT supplies systems with integrated split-butterfly valves, isolator connections and continuous monitoring options. See also our containment solutions.

Ribbon Blender & Paddle Mixer
Suitable for higher volumes and less free-flowing powders. Higher shear force, short mixing times. Often used in food and animal feed production.

When is your mixing process optimal?

A mixing process is optimal when it achieves the desired homogeneity in the shortest possible time, without product damage or contamination risk. Practical criteria:

✓ Mixing efficiency (RSD or CV) < 5% over at least 10 sampling points
✓ No segregation during transport to the next process step
✓ Reproducible results across multiple batches (Cpk ≥ 1.33)
✓ Cleaning validation achievable within the production schedule
✓ Containment class matches the OEL of the active substance

Have doubts about your current mixing efficiency? HECHT offers process analysis and trial runs at our test centre.

HECHT mixing solutions

HECHT Technology supplies mixing installations for pharma, chemistry, food and the battery industry. Our systems are fully custom-configured — from a standalone mixer to a fully integrated mixing installation including dosing, transport and containment.

Relevant HECHT products and topics:

• Dosing systems for accurate powder feeding
• Containment for OEB4–OEB5 processes
• Big bag discharge systems as mixer feed
• Mixing in battery production (cathode, anode)

Frequently asked questions about powder mixing

What is the difference between batch mixing and continuous mixing?
With batch mixing you process a closed quantity per cycle; with continuous mixing the powder flows through the system without interruption. Batch mixing offers more control per lot and is standard in GMP environments.

How long does a typical mixing cycle take?
Depending on material, mixer type and desired homogeneity: 5 to 30 minutes for batch systems. A process trial at our test centre provides the exact mixing curve for your product.

Can a V-blender also process liquids?
No — a V-blender is designed for dry, free-flowing powders and granulates. For adding liquid to powders, use an intensifier bar or a high-shear mixer.

Which mixer type suits OEB4 powders?
For OEB4–OEB5 substances, closed systems with split-butterfly valves and validated containment are required. HECHT supplies certified mixing installations for these applications.

Related guides and solutions

• Dosing and weighing technology
• Screening and classification
• Bulk handling
• Pharmaceutical powder handling and GMP
• Pneumatic powder transport

Our products

• Jett mill

Homogenisatoren zijn cruciaal voor elke toepassing waarbij deeltjes, druppels of vezels gelijkmatig verdeeld moeten worden in een vloeistof of pasta. Of het nu gaat om farmaceutische emulsies, voedingssauzen of batterij-slurries — de juiste homogenisatorkeuze bepaalt productkwaliteit, batchreproduceerbaarheid en procesefficiëntie.

Hoe werkt een homogenisator?

Alle homogenisatoren werken op het principe van het toebrengen van mechanische energie aan een vloeistof om deeltjes te verkleinen en gelijkmatig te verdelen. De drie hoofdmechanismen zijn:

Druk (hogedruk-homogenisatie): De vloeistof wordt met hoge druk (100–2000 bar) door een nauwe opening (klep of orifice) geperst. Door plotselinge drukval treedt cavitatie op, waarbij microbellen imploderen en hoge lokale energiedichtheden produceren. Resultaat: deeltjes van 0,1–1 µm.

Ultrasoon (sonicatie): Een sonotrod (trillende pin) genereert geluidsgolven op 20–40 kHz in de vloeistof. Cavitatiebellen imploderen aan het oppervlak en produceren intensieve micromixing. Schaalbaar tot ca. 200 L/u; ideaal voor lab en pilotschaal.

Mechanisch (rotor-stator, colloidmolen): Een snel roterende rotor (3.000–20.000 rpm) werkt samen met een stationaire stator om vloeistof door nauwe spleten te forceren. Hoge afschuifkrachten verkleinen druppels en agglomeraten. Geschikt voor hoge viscositeiten.

Types homogenisatoren vergelijken

Hogedruk-homogenisator (HPH)
Drukbereik: 100–2000 bar | Deeltjesgrootte: 0,1–1 µm | Capaciteit: 10–10.000 L/u
Toepassingen: farmaceutische injecties, liposomen, nanoëmulsies, zuivelproducten
Voordeel: kleinste deeltjesgrootte, GMP-geschikt, CIP/SIP mogelijk
Nadeel: hoge investering, energie-intensief

Ultrasone homogenisator
Frequentie: 20–40 kHz | Deeltjesgrootte: 0,1–5 µm | Capaciteit: tot 200 L/u
Toepassingen: lab R&D, dispersies, celruptuur, batterij-elektroden
Voordeel: flexibel, snel opschaalbaar van ml naar liter
Nadeel: beperkte capaciteit voor industriële volumes

Colloidmolen
Gap: 0,05–5 mm instelbaar | Capaciteit: tot 5.000 L/u
Toepassingen: mayonaise, pindakaas, farmacie (zalven), pigmentdispersies
Voordeel: verwerkt hoge viscositeiten en vaste deeltjes
Nadeel: minder fijne deeltjesgrootte dan HPH

Rotor-stator mixer
Snelheid: 3.000–20.000 rpm | Capaciteit: batch tot 10.000 L
Toepassingen: emulgeren, dispergeren, oplossen in batch
Voordeel: geschikt voor grotere volumes, eenvoudig te reinigen
Nadeel: minder uniformiteit dan HPH bij nanobereik

Toepassingen per industrie

Farmacie en biotechnologie: HPH voor injectables, liposomale drugformuleringen (mRNA-vaccins), nanopartikels. GMP-gecertificeerde uitvoeringen vereist.

Food en dranken: HPH en colloidmolen voor homogene zuivelproducten, sauzen, fruitpulp. Verlengde houdbaarheid door microbiele reductie.

Batterij-industrie: Ultrasone en rotor-stator homogenisatoren voor kathodesuspensies (NMC, LFP) en anodesuspensies (grafiet). Uniforme deeltjesverdeling is direct bepalend voor cel-capaciteit.

Chemie en coatings: Dispersie van pigmenten, nanomaterialen en vulstoffen in polymeermatrices.

Veelgestelde vragen over homogenisatoren

Wat is het verschil tussen HPH en ultrasone homogenisatie?
HPH is geschikt voor grote volumes (tot 10.000 L/u) en bereikt de fijnste deeltjesgrootte (sub-200 nm). Ultrasone homogenisatie is flexibeler op lab- en pilotschaal maar beperkt in capaciteit. Voor industriële farmaceutische productie is HPH de standaard.

Welke deeltjesgrootte bereik ik met een homogenisator?
Afhankelijk van het type: HPH bereikt 0,1–0,5 µm (100–500 nm), ultrasoon 0,2–2 µm, colloidmolen 1–10 µm, rotor-stator 2–50 µm. De uiteindelijke grootte hangt ook af van het materiaal, de viscositeit en het aantal passages.

Wanneer kies ik voor een colloidmolen in plaats van HPH?
Bij hoge viscositeiten (pasta's, zalven) en grotere deeltjes (>5 µm) is een colloidmolen praktischer en goedkoper. HPH is de voorkeur wanneer sub-micron deeltjesgrootte vereist is en het product pumpbaar is.

Our products

• Jett mill

Silo installations and bulk storage for powder and granulate — definition: A silo installation is an integrated system for storing, conditioning and controlled discharge of bulk goods in powder or granulate form. The installation comprises at minimum a silo tank (steel or stainless steel), a discharge system (rotary valve, screw feeder or pneumatic), level measurement and structural support. For industrial applications in food, chemistry, pharma and the battery industry, HECHT supplies complete silo installations from 1 m³ to >500 m³, including engineering, assembly and commissioning.

Key points

• Silo type selection: steel silos (painted or galvanised) for dry, non-aggressive bulk goods in outdoor placement; stainless steel silos (304 or 316L) for food ingredients, pharma, chemically aggressive products; polyester/GRP silos for corrosive substances; concrete silos for large volumes (grain, cement, limestone) — material choice determined by product, cleaning requirements and environmental class
• Silo sizing parameters: fill weight (ton/m³), bulk density, flow character (free-flowing, cohesive, thixotropic), bridging tendency, maximum storage duration, temperature and moisture sensitivity, ATEX classification of the product dust; fill volume = (batch interval × consumption) × safety margin 1.2–1.5; cone angle: free-flowing product ≥30°; cohesive ≥45°, sometimes mass-flow design required
• Silo accessories: level measurement (radar, ultrasonic, load cells), air filter (HEPA or bag filter on top for dust emission during pneumatic filling), moisture control flap, cone heating/cooling, ATEX earth connection, overpressure protection (explosion safety flap or suppression system), inspection hatch with safety catch
• Process integration: silo coupling to receiving (big bag station, pneumatic transport, tanker truck discharge) and to production (dosing unit, mixer, reactor via rotary valve or screw feeder); gravimetric or volumetric dosing; automation via PLC/SCADA with integrated alarms (empty, full, bridging)
• HECHT silo park experience: 500+ silo installations delivered in the Benelux and surrounding countries; sectors: pharma, food, chemistry, battery industry, construction materials; in-house engineering, prefabrication and assembly teams; FAT and SAT included

HECHT silo installations: Test & Trial Centre in Pörnbach, silo installations bulk storage powder granulate steel silos stainless steel engineering and silo park bulk storage food pharma chemistry complete engineering assembly.

FAQ — Silo installations and bulk storage

How do I calculate the required silo capacity for my production process?

Silo capacity calculation: step-by-step method. (1) Determine consumption: daily or weekly raw material consumption in tons/day; (2) Determine supply frequency: delivery by tanker truck (20–25 tons), big bag (500–1500 kg), or daily small deliveries; (3) Target stock buffer: at least 1 full delivery as reserve + safety margin; (4) Net volume calculation: gross tonnage / bulk density (ton/m³) = m³ net; (5) Calculate gross silo volume: net / fill degree (max 85–90% for powder = space for filter, dust cloud) = m³ gross; (6) Choose a standard size or custom design. Example: consumption 5 tons/day, weekly delivery 20 tons, bulk density 0.6 ton/m³, buffer 1 delivery = 20 tons / 0.6 = 33 m³ net / 0.85 = ~39 m³ gross → rounded to 40 or 50 m³ standard silo. HECHT provides silo capacity calculation as a free engineering service for customers.

What are the GMP requirements for pharmaceutical silos?

GMP requirements for pharmaceutical silos (EU GMP Part II / ICH Q7): (1) Material: 316L stainless steel, Ra ≤1.6µm internal (preferably ≤0.8µm for API contact); FDA-compliant seals (PTFE, food-grade EPDM); (2) Cleanability: inspection hatch >600mm diameter for manual inspection; spray nozzles for WIP/CIP; drain connection at the lowest point; (3) Level measurement: without product contact (radar or ultrasonic) or hygienic (membrane pressure sensor); (4) Ventilation: HEPA filter on air inlet/outlet, integrity testable; (5) IQ/OQ/PQ: installation qualification (IQ), operational qualification (OQ) including calibration certificates, process qualification (PQ) including cleaning validation; (6) Documentation: material certificates (EN 10204 3.1), welding certificates, pressure test. HECHT supplies pharmaceutical silos including a complete qualification package.

Which discharge systems are suitable for a silo with cohesive or poorly flowing powder?

Discharge systems for cohesive powder silos: cohesive or poorly flowing powder (e.g. silica, talc, clay powder, sugar powder) requires active discharge assistance to prevent bridging and ratholing. Options: (1) Fluidisation plates (air cushions in the cone): air injection temporarily fluidises the powder — cheap, effective for lightly cohesive material; (2) Vibrators (vibration motors on the cone or walls): mechanical shock breaks the bridge — effective but can cause compaction with prolonged use; (3) Mass-flow silo (steep cone >70°, smooth internal surface): flows homogeneously without bridging — more expensive but most reliable; (4) Discharge cone / discharge bridge: combined system of cone + rotating discharge cone centrally in the material; (5) Pneumatic assist dosing: air injection nozzles at multiple points. HECHT designs cone and silo profiles based on Jenike shear-cell analysis for worst-case discharge behaviour.

Author: Joost van Velzen, Managing Director Hecht Technology B.V.

Related guides and solutions

• Pneumatic powder transport (complete guide)
• Dosing and weighing technology
• Pressure vessels and storage tanks
• Columns and process towers
• Solutions for the chemical industry

Hecht Technology: storage solutions for bulk goods

In addition to silo installations, Hecht Technology supplies pressure vessels and storage tanks for smaller to medium storage volumes of powders and granulates, including GMP and ATEX versions. For process integration between storage and processing, our systems offer the same hygienic connection standards as our filling and dosing installations.

Our products

• Pressure vessels and storage tanks

Single use versus stainless steel in biopharma - definition: The choice between single use (SU) technology and stainless steel (SS) systems in biopharma comes down to capital investment, flexibility, cleaning validation burden, production scale and sustainability. Hybrid strategies combine SU for upstream flexibility with SS for downstream high-volume processing.

Key points: single use versus stainless steel biopharma comparison

• Capital cost vs operating cost: SU systems have 40-60% lower capital expenditure (CAPEX) but higher variable costs due to disposable materials. SS installations are capital-intensive but have low consumable costs long-term. Break-even occurs at larger batch volumes and high utilization rates.
• Cleaning validation: SS systems require full CIP/SIP validation per product changeover per EU GMP Annex 15. SU eliminates this entirely, delivering 20-40% time savings per campaign in multi-product facilities and reducing inspection risk.
• Flexibility and time-to-market: SU systems are faster to install (weeks vs months), easier to reconfigure for new molecules, and suited to clinical phase I/II production. SS is optimal for commercially validated processes with stable volume.
• Sustainability profile: SU generates plastic waste but saves significantly on water consumption (WFI for CIP), steam energy and cleaning agents. Lifecycle analyses show mixed results depending on energy mix, water price and waste processing route.
• Scalability and process intensification: SS remains dominant for volumes above 2000 litres of fermentation and high-titre applications with multiple batches per week. SU is ideal for batches up to 2000 litres, multi-product sites and fast-growing biopharma with a variable product portfolio.

Compare technology choices for your biopharma facility via our page on containment systems, discover validation options at our Test & Trial Centre, or view our solutions for big bag discharge stations for bulk raw material handling in pharmaceutical manufacturing.

The Core Question: Single Use or Stainless Steel?

When designing or expanding a biopharma manufacturing facility, the choice between Single Use Technology (SUT) and traditional stainless steel (SS) equipment is one of the most strategic decisions. There is no universal answer — the optimal choice depends on production volume, product portfolio, investment horizon and operational strategy.

Hecht Technology supports pharmaceutical and biopharmaceutical manufacturers in making this choice with a structured technology evaluation, including total cost of ownership (TCO) analysis and facility strategy. In this article we outline the key differences and decision criteria.

Comparison on the Key Dimensions

Capital Expenditure (CAPEX)

Single use wins on CAPEX for new facilities. Eliminating the CIP/SIP installation (piping, pumps, vessels, validation) significantly lowers construction costs. Studies from ISPE and Biophorum show CAPEX reductions of 25–40% for comparable SUT facilities versus fully stainless steel facilities at clinical scale (up to ~500L).

At large commercial production volumes (multiple batches per year >1000L), the balance tips: the high consumable costs of bags outweigh the CAPEX savings on utilities.

Operating Expenditure (OPEX)

Here SS wins at scale. Single use consumables (bags, sensors, tubing) are significantly more expensive than the operating costs of a well-managed SS installation at large volumes. A 2000L single use bag typically costs €3,000–8,000; a comparable SS batch has lower direct material costs but higher labour and energy costs for CIP/SIP.

Rule of thumb: at production titres >5 g/L and volumes >1000L per batch, SS often becomes cheaper in OPEX.

Flexibility and Multi-Product Manufacturing

Single use wins convincingly on flexibility. Switching between products only requires replacing the disposable components — no validation of cleaning procedures per product combination. For multi-product facilities with varying campaigns, SUT is almost always preferred.

Scale Limits

SS has no scale limits; commercial bioreactors of 20,000L and more are common. Single use bioreactors are commercially available up to ~2000L working volume. Above this limit, SS is the only option, or a hybrid approach where the upstream SUB feeds the SS downstream.

Cross-Contamination Risk

Single use wins. New plastic per batch eliminates the risk of insufficient cleaning or carry-over from previous campaigns. This is particularly relevant for HPAPI products and multi-product facilities.

Sustainability

SS wins on sustainability at high volumes and long facility horizons. Plastic waste from SUT is a drawback, although the reduction in water and energy consumption for CIP/SIP partially offsets this.

Decision Matrix: When to Choose What?

• Clinical production (Phase I/II): → SUT, always. Speed and flexibility dominate.
• Multi-product commercial manufacturing: → SUT or hybrid. Flexibility advantage weighs heavily.
• Single-product large-volume commercial (>2000L/batch): → SS, or hybrid with SUT upstream.
• New facility, limited budget: → SUT for lower initial investment.
• Expanding an existing SS facility: → Hybrid: add SUT for flexibility, keep SS for core processes.
• Cell and gene therapy, mRNA: → SUT, almost always. Small volumes, high product value, strong flexibility required.

The Hybrid Model: The Best of Both Worlds

An increasing number of manufacturers are choosing a hybrid approach: single use for upstream (seed train, production bioreactor up to 500L) and stainless steel for downstream (chromatography, ultrafiltration, formulation). This combines the flexibility advantages of SUT with the scale advantages of SS at the purification steps, where volumes are smaller and the OPEX burden is manageable.

Total Cost of Ownership: The Right Calculation Method

A sound SUT versus SS decision requires a 10-year TCO analysis that accounts for all factors: CAPEX, consumable costs, energy, water, waste processing, labour, validation and downtime. Hecht Technology performs these TCO analyses as part of facility strategy projects.

Contact us via hecht-technology.nl for a tailored analysis.

FAQ - Single Use versus Stainless Steel Biopharma

When do you choose single use and when stainless steel in biopharma?

Single use is ideal for: clinical phase I/II production, multi-product facilities with frequent product changeovers, low to medium volumes (up to 2000 L), fast time-to-market and limited cleaning validation budget. Stainless steel is better suited to: high-volume commercial product, stable process portfolio, high utilization rate and long-term cost optimisation.

What are the total costs of single use vs stainless steel over 10 years?

At volumes up to 500 litres and fewer than 3 batches per week, SU is typically cheaper over 10 years. Above 1000 litres with high utilization, the balance shifts to SS. Add cleaning validation costs (50,000-200,000 euros per product), WFI water consumption and depreciation to the TCO calculation for an accurate comparison.

Can single use and stainless steel systems be combined in the same facility?

Yes, hybrid strategies are common in commercial biopharma. Typically: SU bioreactors and SU mixing systems upstream combined with SS centrifuges, SS chromatography columns and SS UF/DF systems downstream. This optimises flexibility upstream and process intensity downstream.

How does the FDA assess the use of single use systems versus traditional stainless steel?

The FDA fully accepts SU systems provided the following can be demonstrated: extractables/leachables study (USP <665>), sterility assurance on delivery, integrity testing per batch, supplier DMF and batch traceability. Process Analytical Technology (PAT) enables monitoring in SU bags in line with FDA PAT Guidance.

What is the environmental impact of single use systems compared to stainless steel?

SU saves up to 87% water consumption and up to 30% energy compared to SS with CIP/SIP, but generates plastic waste (5-15 kg per batch for a 200-litre system). Lifecycle analyses (LCA) show that the net CO2 footprint depends on the local energy mix and waste processing infrastructure. Suppliers are working on recyclable multilayer films.

Our products

• Single-use isolator