Vacuum Belt Dryer Series

  • 20 years experience in Vacuum Belt Dryer(VBD);
  • Has a professional technical R&D team,specialized in researching and developing advanced Vacuum Belt Dryer(VBD);
  • Many patents for Vacuum Belt Dryer(VBD);
  • Over 500 sets Vacuum Belt Dryer(VBD) around the world;
  • GMP standards;

Pilotech Vacuum Belt Dryer Series

Compared with other types of dryers, Shanghai Pilotech’s vacuum belt dryer has low drying temperature and low energy consumption, which is 1/3 of the energy consumption of spray dryer. It is suitable for high-viscosity materials, and the dried materials have good fluidity and solubility.

Vacuum Belt Dryer ModelDiameter






Heating Exchange AreaHeating Temperature


Moisture Content Of Feeding MaterialMoisture Content Of Dried ProductHeating ResourceWater Evaporation


Dryer Body








Steam or Hot water or

Hot oil




Pilotech Vacuum Belt Dryer Series

  • Realize continuous feeding and continuous discharging under vacuum condition;
  • Complete drying and crushing under vacuum condition;
  • It can dry high-viscosity materials such as Chinese herbal medicine extract, etc.;
  • Start discharging in 30-60 minutes, and the powder discharging rate is 99%;
  • Heat sensitive materials will not be deformed;
  • Low operating cost, the cost is 1/3 of the cost of spray drying;
  • It can be equipped with online CIP system, in line with GMP specifications.

The vacuum belt type continuous dryer has solved the problems which exists in the traditional Chinese medicine industry for a long time: many extracts are difficult to dry, the spray drying temperature is too high and the heat sensitive substances are easily destroyed. The vacuum oven has a long drying time, high energy consumption and intermittent operation. It is easy to contaminate bacteria and absorb moisture, and cannot meet GMP quality standards.

The successful development of the vacuum belt dryer has played a very active role in promoting the drying problems in the industries of traditional Chinese medicine, pharmaceutical intermediates, fine chemicals, food and health products, and is the best product to replace spray drying and vacuum oven drying. Such as traditional Chinese medicine industry: Salvia miltiorrhiza, compound salvia miltiorrhiza, Chuanxiong, Angelica, Andrographis paniculata, Ganoderma lucidum, Sophora flavescens, ginseng, Acanthopanax senticosus, etc.; food and health products industry: coffee, malted milk extract, fruit treasure, instant milk powder, instant tea, etc.;

It has very good application effects to fine chemicals, pigments, pesticides and other industries.

The vacuum belt dryer not only has low drying temperature and continuous production, and also has small loss, less waste and easy operation in the drying process. The most important thing is to reduce labor intensity and save a lot of energy. Compared with vacuum drying ovens of the same output, it can save 65% electricity consumption, 70% steam saving. It can save 75% electricity and 85% steam compared with spray dryers of the same output.

  1. Vacuum Belt Dryer Principle

The material to be dried is fed into the vacuum chamber of the dryer through a screw metering pump, and is uniformly shoaled on the conveyor belt by the cloth motor. A special roller drive conveyor belt driven by a motor and runs at a set speed. There are independent heating plates and a set of cooling plates under the conveyor belt. The conveyor belt is closely attached to the heating plates and cooling plates, and transfers the heat required for drying to the materials and cooling by contact heat transfer. Set the operating speed of the conveyor belt according to the nature of the material. When the material is transported by the conveyor belt from one end of the cylinder to the other, the material has been dried and cooled. When the conveyor belt is folded back, the dried material cake is peeled off from the conveyor belt. After being pulverized by the pulverizing device, it is discharged through the butterfly valve. The obtained particles can be directly made into capsules or tablets.

The whole equipment adopts PLC control. Operate the equipment through the man-machine interface of the PC. Set up a touch screen operation panel near the dryer and configure a graphical interface, which can display various process parameters, production data and other parameters, which can be modified and adjusted in real time.

  1. Schematic Diagram of Vacuum Belt Dryer Structure
Vacuum belt dryer Principle

Vacuum belt dryer Principle


Vacuum Belt Dryer (VBD)

Vacuum Belt Dryer (VBD)

  1. Technical Characteristics of Vacuum Belt Dryer

(1)Low drying temperature, low energy consumption, no pollution, continuous production, automatic control, meeting GMP requirements;

(2)Drying at low temperature, and can be adjusted according to different materials (35℃-90℃);

(3)The product has a certain degree of crystallization during the drying process. After crushing, the pellets have good fluidity and can be directly filled into capsules.;

(4)The feeding speed can be adjusted accurately, even when the feeding amount is small, the distributing device can distribute evenly;

(5) Each conveyor belt in the box is individually controlled by a frequency conversion motor;

(6)Automatic granulation, continuous discharge of dry particles into the storage tank under vacuum, the storage tank for dry particles can be replaced during the automatic drying process;

(7)Low energy consumption and low noise;

(8) The movement of the conveyor belt is controlled by a frequency conversion speed motor, with correction and tension adjustment functions;

(9)The preparation tank is equipped with a stirring device and a constant temperature device, which can be heated and mixed when adding auxiliary materials;

(10)PC-based control system, friendly man-machine interface, convenient operation, flexible modification of process parameters;

(11)The conveyor belt has a variety of specifications from 1 to 10 layers, customized according to user requirements.

Note: The equipment can be customized according to customer requirements and product characteristics.

Vacuum Belt Dryer Guide 

Over the years, Vacuum Belt Dryers (VBDs) have gained popularity, thanks to their ingenious technology that effectively dries a wide range of liquid and paste materials. Unlike the traditional dryers, VBDs makes it possible to dry thermal-sensitive products (easily destroyed by high temperatures) and high-viscosity raw materials. The viscosity of a liquid corresponds with the concept of “thickness.”

We’ve discussed all you need to know about Vacuum BeltDryers – from its range of application, production process to its market selection techniques. 

How a Vacuum Belt Dryer Works 

A VBD is a continuous and automated in-feed (liquid & paste) and discharge drying equipment that uses a vacuum to control the drying process. Using a high vacuum, the raw materials’ boiling point (temperatures) reduces, and the moisture sublimes to gas directly. 

An infeed pump conveys liquid products into the dryer body. Belts move the heating plates evenly, and this is critical for getting quality end products. What follows is a continuous process –evaporation of moisture, drying, cooling to discharging. All these happen at controlled temperatures, typically decreasing from one cycle to the next. 

A vacuum crusher equipment turns the solid raw material into powder or granules of varying sizes (depending on the required specifications and use).

VBD Range of Application 

A Vacuum belt dryer finds its application in a wide range of industries – especially for products that are difficult to dry and process using the traditional dryer techniques. These include, but are not limited to: conventional and western pharmaceutical products, biological products, food, health foods, chemicals, and food additives, etc. We’ve highlighted each of these below.

  Food Products 

VBDs are used to produce food products such as malt extract, tea powder, corn paste, instant beverage, and cocoa powder. The fineness of the powder and the granules’ size for food products such as coffee can be controlled using specific crusher equipment. Other food products include: Rice protein powder, hops extract, wheat essence, vegetable juice concentrate, meat extracts, chocolate products, instant soup, etc. 

Pharma products

Pharma products such as Chinese medicine extracts, embryos, plant extracts, and PVPK products are primarily produced using Vacuum Belt Dryers. Before VBDs came into the market, producing traditional Chinese medicine was a headache. Most of these extracts are difficult to dry while some are thermal-sensitive and should be handled properly to avoid losing their medicinal properties. Other pharma products processed using VBDs are vitamins, fermentation broth, antibiotics, and active medicinal substances, etc. 

Chemical Products

VBDs are also used to produce chemical products such as emamectin benzoate (an insecticide used in pest control) and the lithium battery used in a wide range of electronic products.

Laboratory VBD applications 

Several organizations, learning institutions, and research companies use vacuum belt dryers in their Research and Development needs. Their specific applications often vary based on the type of research and the elements they are using to conduct the study – could be food, chemicals, or pharmaceutical products.

The Step by Step VBD Drying Process 

A vacuum dryer is designed more like an industrial boiler or a horizontal silo, with synthetic mesh-like belts on the inside. Depending on the design, the dryer belts sit on hot water or steam-heated elements. All the parts used, from the vacuum chamber to the conveyor belt, are food-grade.   

 Most vacuum belt dryers will operate at vacuum conditions from 10mbar to around 80mbar. This is designed so it can suit a wide range of production needs. The moving belt surface varies in size, and you can choose one based on your preference. A single vacuum band dryer is used for small-scale production, while a typical ten-belt VBD is used for commercial production. 

VBDs offer a continuous working mechanism that’s easily customizable to suit your production applications. The raw materials go through many processes: from feeding the raw materials in liquid or paste form to getting end products as granules or powder.

As highlighted above, these processes include: 


The heating temperatures can be adjusted from 30-150 degrees Celsius, depending on the raw material’s nature and expected end-product. The typical moisture content of raw materials would range from 20-80 percent.


The conveyor belt is attached to the heating and cooling plates. These plates transfer the required amount of heat (by contact heat transfer) instantly for the drying and cooling process. All these take place under vacuum conditions. The drying process is continuous and controlled by the Programmable Logic Controller (PLC) module.  

Automatic granulation and Crushing 

One thing about drying raw materials at relatively low temperatures is that they crystallize, making it easy to crush into a particular grain size. Depending on the expected end-product, crushing is controlled to ensure end-products have the desired feel and fluidity.

A VBD handles liquids, viscous products, and concentrates. Since all the processes are automated, there’s no room for human errors – hence no oxidation or inconsistent quality issues. 

Benefits of Vacuum Belt-Dryer continuous process

 A vacuum belt dryer comes with several benefits. In itself, the continuous drying process is a bespoke engineering solution that came when the change was more than a necessity. We’ve highlighted some VBD advantages below. 

Sustainable Technology

VBD is a combination of advanced tech-solution and practicality. It does an excellent job of retaining the aroma, color, and flavor in its end products; this is something that traditional drying technologies don’t guarantee. An example is the spray dryer that destroys heat-sensitive substances due to the high drying temperatures. 


The low energy consumption of VBDs is an added advantage for companies in the commercial processing industry. This translates to low electricity bills and reduced overhead costs, which drives profitability. Unlike the vacuum oven that has a long drying time with high energy consumption, VBDs use 1/3 of the energy consumption of a typical spray dryer.

Retains Critical Elements with enhanced quality  

One of the properties of a vacuum belt dryer is enhanced evaporation at reduced pressure. This helps eliminate oxidation while preventing undue damage to the raw material’s integrity – for example, the chemical composition of a product or the plant extract’s effectiveness as a pharmaceutical product. When making powdered sweeteners, VBDs preserve unique product characteristics such as essential amino acids, antioxidants, vitamins, and mineral components.

The solubility of End Products 

The solubility of VBDs’ end-products is unmatched. Due to the consistent and high-quality production process, the powder produced is highly soluble in cold liquids.

Better Customizations 

Temperature zones allow for product-specific feeding with the option to adjust the feeding parameters to suit your individual needs. This is made possible by a PLC control system.

Due to the high-quality processing, continuous drying by VBD meets and even exceeds the Good Manufacturing (GMP) standards. With a Clean-In-Place (CIP) system, you won’t have to worry about the tedious daily cleaning procedures.

The Vacuum Belt Dryer Production Process

Manufacturing a Vacuum Belt dryer takes more than just a one-step process. For efficiency, accuracy, and quality, the production follows a step-by-step procedure. At each step, there’s a quality control inspection to ascertain that everything is proceeding as required. With such a process, it’s easy to increase productivity, which allows for mass production without compromising quality.

Assembling Raw Materials

As with any production line, the VBD production process begins with the sorting and assembly of high-quality raw materials. These include food-grade stainless steel, heating and cooling plate materials, conveyer belt, etc. This process is necessary to ensure the success of the entire project. From here, it’s possible to know which materials to source before preparing for the next production step.

Processing the Parts

When receiving raw materials, they are often in a form that cannot be used immediately. Processing of parts means getting them ready for the job. More often, this involves cleaning the parts, resizing them, etc.  


Joining the several metallic parts of a vacuum belt dryer is a challenging task that requires the best of talents, leverage, and experience. More often, the welding process is automated to ensure fast and uniform production. However, this isn’t to say that every part of the welding process is automated. There are those areas where manual welding is necessary to guarantee quality work. Every product goes through inspection before and after manual or machine welding.

Parts Polishing

After joining the various parts of the VBD, it’s necessary to do some polishing to preserve the adjoined parts’ integrity. This is done to remove heat tints, reshape misaligned parts, and ensure a smooth and even finish. A weld polishing machine will get the job done in most cases, but manual polishing may be required when getting around the corner welds. 

Assembling Parts

The majority of the polished parts need to be assembled before moving ahead with the production process. This isn’t the final assembly, but one that comes before the mirror-polishing of stainless steel casting. The assembly process may or may not require further welding. It all depends on the parts being assembled. 

Casting Polishing

Across major industries, there’s usually an element of casting involved in the production process. Casting polishing needs to be done to remove the sprues and tough skin from the stainless steel. Choosing the right casting polishing tool is key to ensuring a mirror polish while preserving the material’s quality and functionality. This step could involve a sequential polishing process to ensure a subtle and well-blended finish. The tools used include large abrasive flap wheels, interleaved flap wheels, etc. 

 Final Assembling

The major VBD parts enter a final assembly. This process is often automated, with little to no human labor. However, it’s necessary to check that all the pieces click into place and that every element occupies its rightful position. While this step may not be labor-intensive, it’s one that needs accuracy and precision to avoid costly errors that may propagate and affect the products’ lifetime.


Inspection is often done by the quality assurance team that consists of professionals from all the major departments – from control and safety engineers to the top-level management roles. Before a machine is tested, inspection is done to ensure all parts are intact and minimize incidents and probable damage. All the individual products are inspected before testing to ensure only the best machines get to the market.

 Electrical Control Inspection

Besides inspecting the various parts of the Vacuum belt dryer, a thorough inspection of the electrical control system is done for advanced safety. The control system is one of the most critical parts of any machinery. If a control unit fails, there’s very little that can be done to bring the machine under control. This makes it a priority to inspect and test the different electrical components making up the VBD.  

 Pneumatic Control Inspection  

VBDs’ pneumatic system comprises all the components that use compressed air to transfer energy from one part of the machine to the other. For example, a compressor used to power all the motors, pumps, and cylinders is an essential part of the pneumatic system that needs proper inspection. Any component that stores, moves, controls, or provides compressed air should also be inspected. 

 Vacuum Belt-Dryer Buying Guide

Choosing a vacuum belt dryer from the market can be a daunting task. If you’re like many, you would want to invest in a quality, durable, and reliable product that will serve all your needs without incurring extra costs. With the many options from several manufacturers on the market, convenience and quality should always be your top considerations. That said, we’ve covered some of the crucial factors you should consider when buying a VBD.

Vacuum Belt-dryer Features 

There are different types, models, and designs of vacuum belt dryers. While the principle of operation remains the same, certain unique features come with each vacuum dryer set. These include the size, heating exchange area, heating source, and heating temperature range. You can always ask for further clarification on what these features mean and their importance as far as continuous drying is concerned.

Production capacity 

When choosing a VBD that will suit your production needs, you always want to prioritize both the present and future needs. You don’t want to buy a small capacity VBD that won’t be relevant in the next five years or so. Always have your priorities right and invest in a model that’s both scalable and sustainable. 

A great manufacturer will specify the size and production capacities in ranges that make sense to the customer. That means the customer should have an easy time making a choice based on their needs, and not based on what the manufacturer offers. 

Warranty period

Many people don’t give a product’s warranty the attention it deserves. While a warrant is an assurance of quality and trust between the manufacturer and the customer, there’s more to having a long-term warranty than just the number of years your VBD remains covered.

A warranty product’s period is often an assurance of quality. A confident manufacturer will offer nothing less of a 1-year warranty. This gives you enough time to use the vacuum belt dryer and test every aspect of it before using it for the long term.

Purchasing Process 

When buying such a high-investment product, the purchasing process should be procedural, legal, and professional. Purchasing good practices begin with a show of interest and a request to purchase/requisition. What follows is the customer selection, purchase order, fulfillment, receipt, invoicing, and payment.

Many times, when the customer isn’t knowledgeable enough about the product, it’s essential to begin with a consultation process, which could involve technical scheme determination and testing to ensure everything works as you would expect. Business negotiation follows, after which the procurement process can begin.    

The purchasing process is crucial as it allows you and the manufacturer to communicate effectively and share vital thoughts about the product.

Manufacturer Reputation 

Trust in business is hard to come by. The manufacturer’s reputation is one of the critical factors to consider when buying a Vacuum belt dryer. While the manufacturer’s years of experience in the industry is one of the determining factors, it’s not the only recipe for success in selecting and buying a VBD. Here’s why:

  • The technology used in the production process is of greater importance
  • Quality often begins in the product design and material selection process
  • Customer satisfaction speaks volumes – this is often a measure of the quality of services, from customer support to troubleshooting and other services.

An excellent way to measure the company’s reputation is to look around and see who is using the product. More often, a product used by institutions for learning and research purposes, large production companies, or government facilities is enough to convince you of the product integrity and the manufacturer’s reputation. 


If you’re on a budget, you want to purchase a product that fits your needs. Several factors determine the cost of a product, from internal factors such as the cost of production to external factors such as the market dynamics and government policies. You always want to do your research and make sure you’re not making decisions based on the pricing alone and ending up buying what you don’t want. 

Why Choose Pilotech Vacuum Belt Dryer? 

At Pilotech, there’s more than meets the eye. Your search for a vacuum belt dryer ends here as you find a wide range of high-quality vacuum belt dryers to suit your unique needs. Below are some of the reasons why choosing us is the best investment you can make:

Quality Products and Services 

Buying a high-quality product is not enough. You want to purchase it from a manufacturer that cares about you and wants to solve your problems and everything that may arise along the way. At Pilotech, we evaluate your unique needs and provide just the perfect product for your specific production requirements. 

Not only are our products of high quality, but our customer support is also exceptional. We are intentional about this – since a quality product without effective customer support remains a significant source of frustration to the end consumer.

Market Experience 

With more than 20 years in the VBD industry, we fully understand what it takes to amaze our customers. More than 3,500 scientific institutions use our products across the world. 

This is a big deal for us, and our work is to ensure consistency and unmatched support services to all of them. 

As a leader in the vacuum belt dryer technology, we believe that your production needs are unique, and there’s no one-size-fits-all solution. When you come to us, we keenly listen to understand what you need. We then weigh the options to see if there’s a ready product in the market to meet your requirements. If there’s none, we’ll proceed to customize a product to match your needs and product characteristics. 

A great team of exceptional talent 

As a manufacturer specializing in high-tech products, acquiring a team of outstanding talent is part of our top priorities. This is what we have done over the years – investing heavily in our Research and Development. We are always striving to keep up with ever-changing technology to keep developing advanced market products.

Besides the above reasons, below are the other advantages you get by working with us:

  • You get a variety of options to choose your perfect VBD model 
  • All the VBDs meet the GMP standards.

One of our greatest perks is that we built our products to last a lifetime. Thus, our products serve more than 70% of China’s market, with exports to more than 60 counties and regions worldwide.

Wrapping It Up 

Vacuum belt dryers are becoming the go-to option for industries looking for a continuous drying machine that guarantees automated processing and high-quality end products. The vacuum technology isn’t only a game-changer, but an innovative solution that has helped solve several industry problems. 

Not long ago, it was almost impossible to dry heat-sensitive products without deforming them. Now, even the difficult to dry traditional Chinese medicine has seen a significant production in the market. 

When buying a vacuum belt dyer, it’s recommended you do your research and weigh the options before making a purchase a decision. Hopefully, this guide has been of great importance on your journey to selecting a VBD for your production needs.

 If you would love to inquire more about our Pilotech Vacuum belt dryer, contact us today, and we’ll be glad to be of help.  

Vacuum Spray Dryer: The Ultimate FAQs Guide

This guide will answer all questions you have about vacuum spray dryer.

If you want to learn about the components, working principle, nozzle types, material or optimizing performance, you will find all information here.

So, if you want to be an expert in this spray drying machine, read this guide.

What is Vacuum Spray Dryer?

Vacuum spray dryer refers to a type of spray drying equipment that featuring a low-pressure drying tower chamber.

Low pressure in the drying chamber boosts the thermodynamic parameters for removal of water, enabling drying at considerably reduced temperatures.

The spray dryer type is suitable for drying heat sensitive and hygroscopic substances.

 Vacuum spray dryer

 Vacuum spray dryer

What are the Features of Vacuum Spray Dryer?

  • Has Color Touch Screen HMI
  • Uses PLC System
  • Most have a collector, cyclone separator, spray chamber, and body made of Stainless steel
  • Inlet temperature range from 50-200 degrees Celsius

Which are the Main Components of Vacuum Spray Dryer?

The key parts of a vacuum spray dryer consist of the following:

Vacuum spray drying system

Vacuum spray drying system

1) Process Control Systems

Most types of vacuum spray dryers employ PLCs as the control system.

2) Feed Supply System

This the part where the concentration of raw material/feedstock takes place.

It comprises of the following components:

  • Feed tank(s)
  • Feed/Supply pump
  • High-pressure pump/Homogenizer
  • Filter
  • Concentrate heater
  • Feedline

3) Atomizer/Spray Nozzle

It is here where the vacuum spraying machine optimizes the process of evaporation.

The atomizer helps in the conversion of liquid suspension into fine droplets.

There exist three main types of spray nozzles used in vacuum spray dryer including:

  • Pressure nozzle atomizer
  • Rotary atomizer
  • Two-fluid nozzle atomizer

4) Heating System

The heating system supplies the hot air necessary for vacuum spray drying.

It employs either a direct or indirect method of heating.

Indirect heating, the air, and the heating source are in direct contact.

Conversely, with the indirect method, a heat exchanger helps in indirect heating of the drying air.

Here are the components of the heating system of a vacuum spray dryer:

  • Air Heater
  • Air Filter
  • Air Disperser
  • Supply Fan

Additionally, the most crucial variables in the hot air supply system are air flow rate, temperature and thermo-physical properties.

5) Drying Chamber

The process of vacuum spray drying takes place in this chamber.

It is where the spray dryer eliminates moisture from the feedthrough spraying it as tiny droplets into hot air.

You determine the size and measurements of the drying chamber by the type of raw material.

Moreover, feed and inlet heated air distribution also dictate the size and dimensions, in addition to the atomizer type and feed rate.

6) Powder Recovery Systems

Applying centrifugal force, the system separates the fine powder leaving the vacuum spray dryer from the hot drying air.

Here are the different types of powder recovery systems you can use in vacuum spray drying equipment:

  • Wet Scrubber
  • Bag filter
  • Cyclone
  • Combinations of the three

7) Powder return System and Powder After-Treatment System

They include the following system

  • Powder sieve
  • Fluid bed dryer or cooler
  • Pneumatic conveying and cooling
  • Lecithin treatment System

How Does a Vacuum Spray Dryer Work?

A vacuumspray drying machine is ideal for drying thermally sensitive materials and substances that are prone to absorbing moisture from air.

It operates by developing a vacuum to decrease the pressure in the spraying chamber below the water vapor pressure.

Consequently, the pressure drop results in the boiling of water, which in turn increases the rate at which the equipment dries products.

Other typical working principles of spray dryers remain the same including:


The vacuum spray dryer works by atomizing the feed and contacting the atomized liquid with hot air.

The atomizer serves various purposes including metering flow into the drying chamber, producing droplets of the desired size.

More it also ensures uniform distribution of the liquid droplets within the drying chamber.

The atomization stage creates the optimum environment for evaporation.

This results in a dried powder featuring the desired properties.

Rotary atomizers and pressure nozzles help in the spray formation.

Vacuum spray dryer can have just a single to over 100 spray nozzles.

Droplet-Air Contact

In the drying chamber, the system brings into contact the atomized liquid with hot air at a vacuum.

This vaporizes 95 percent of moisture in the droplets within seconds.

The manner in which spray media interacts with hot air within the vacuum spray drying machine affects droplet behavior during the drying stage.

The interaction has a direct effect on the dried product properties.

Atomizer position with respect to the air inlet determines the contact type between the air and spray.

The location of the nozzle headers are normally at the vacuum spray dryer top and spray down.

Droplet Drying

Evaporation of moisture happens in 2 stages.

In the initial step, the saturated air temperature at the droplet surface is roughly equal to the drying air temperature.

There exist adequate moisture within the droplet to substitute the evaporated fluid at the surface.

Furthermore, the process of evaporation happens at a comparatively uniform rate.

The second drying phase commences if there is no more sufficient water to sustain a saturated environment on the surface of the droplet.

Consequently, this leads to the formation of the dried shell at the droplet surface.

The rate of evaporation relies on the moisture diffusion via a dried shell that gets thicker during the process of drying.

Vaporization rate drops swiftly during the second stage of drying in a vacuum spray dryer.

Different products feature varying particle-forming attributes and evaporation. Some contract, others expand, disintegrate or crack.

The resulting particles might be comparatively homogenous hollow spherical partilces, or permeable and irregular-shaped products.

· Separation

After completion of drying, you must separate the product particles from the hot air.

The vacuum spray dryer achieves primary separation by the powder falling to the base of the drying chamber.

Some particles portion stay entrapped with the air, which you must recover in separation equipment.

You can utilize electrostatic precipitators, bag filters and cyclones for the ultimate separation stage.

Finally, use wet scrubbers to clean and cool the drying air before releasing it into the atmosphere.

What are the Advantages of Vacuum Spray Dryer?

The key benefits of vacuum spray dryer include:

  • It is energy efficient since it requires less energy for spray drying.
  • Performs drying faster than other types of spray drying machines.
  • Vacuum spray dryer is cost-effective due to its fast drying capability
  • Saves on processing times
  • Less damaging spray drying technique due to reduced dwell time and temperature.

What are the Applications of Vacuum Spray Dryer?

You can use a vacuum spray dryer in a broad range of applications requiring the creation of free-flowing powder.

The equipment has successfully processed substances in the following fields:

  • Chemical industry
  • Detergents, soaps and surface active agents
  • Dyestuffs and pigments
  • Blood
  • Organic chemicals such as Polymers and Resins
  • Food and Beverage products for example milk and egg products
  • Pharmaceutical products

How do you Specify Vacuum Spray Dryer?

Here are the key specifications of Vacuum Spray Dryer that you must look for:

  • Power
  • Evaporating Capacity
  • Minimum input temperature
  • Heater power
  • Spray gas
  • Nozzle jet
  • Nozzle type
  • Possible particle size range
  • Operation mode
  • Maximum Sample feed
  • Minimum sample volume
  • Spray chamber material
  • Inlet temperature
  • Cyclone separator material
  • Body material
  • Seal of cyclone/cylinder
  • Outlet temperature
  • Dimensions
  • Weight
  • Display
  • Thermal protection
  • Deblocking
  • Atomizer material

Which are the Materials you can Dry using Vacuum Spray Dryer?

Vacuum spray dryer machine

Vacuum spray dryer machine

It is possible to dry the following materials using Vacuum spray drying equipment:

  • Heat-Sensitive materials like biological products including viable bacteria and enzymes preparation
  • Natural product extracts having high sugar content
  • Hygroscopic materials
  • Thermolabile polymer materials
  • Substances that gasify if they get in contact with heat

What is the Difference Between Vacuum Spray Dryer and Vacuum Freeze Dryer?

A vacuum freeze dryer involves a low-temperature dehydration operation.

It entails freezing the product, decreasing air pressure, and eventually eliminating the water through sublimation.

Though comparably new to the sector, the vacuum spray dryer offers some advantages, like the capacity to function with higher throughput.

The difference between the two types of vacuum drying equipment lie in:

Vacuum freeze dryer

 Vacuum freeze dryer

· Drying Process

Vacuum freeze dryers operates by initially freezing a product, often in a controlled way.

Freezing helps in manipulating the structure of the ice crystal of the product, which you then place in a vacuum.

At this point is where primary drying (sublimation) takes place, to eliminate the unbound water.

To help in the bound water sublimation, secondary drying follows, which takes the materials to a specified residual moisture level.

The vacuum freeze drying machine requires more energy in the secondary drying process since the target is bound instead of unbound.

This is because of the processing of increasing shelf temperatures to +20 degrees and low atmospheric pressure.

The goal is to transform ice straight into water vapor, avoiding the liquid phase.

The balance between vacuum and temperature ensures successful batch production post drying.

On the other hand, a vacuum spray dryer involves a simpler and quicker process.

It entails transforming a liquid suspension into dry powder in a single step.

The spray drying equipment atomizes the solution into fine droplets, which it quickly dry in a large chamber utilizing hot air.

A cyclone finally collects the resulting dry powder.

Though less costly, the main disadvantage of a vacuum spray dryer is the high processing shear force and temperature.

· Temperature

Products temperatures during primary drying in vacuum freeze dryer are usually below zero degree Celsius.

During secondary drying, the temperatures often range from 20 to 30 degrees Celsius.

Conversely, temperatures of products in vacuum spray dryers are often above 50 degrees Celsius.

The direct effect of such higher processing temperatures might be a general loss of:

  • Color/smell
  • Efficacy
  • Taste
  • Nutritional value, that is nutrients in foodstuff
  • Proteins degeneration
  • Biological yield (higher level of cells log reduction i.e. bacterial)

· Quality And Cost

Having the potential of larger throughput, you can consider vacuum spray dryers to be continuous process equipment.

This is different from the batch format related to the vacuum freeze-drying machine.

Although the initial cost of a vacuum spray dryer is usually low, this is not often the situation with more complex formulations.

Conversely, there is accurate regulation of low processing temperatures in the vacuum freeze dryer.

This reduces any risk on the intrinsic properties of the products.

The control prevents surpassing of glass transition temperature, collapse and eutectic melt.

In a vacuum freeze dryer, products that need several coating layers will have to undergo several coating operations.

These processes can be cost-prohibitive and time-consuming.

· Applications in Industry

You can use both types of industrial drying machine in a wide variety of applications.

Vacuum freeze dryers help in the preservation of injectable vaccines, food and dairy products, fine chemicals, and different cell types.

Moreover, vacuum freeze dryer is ideal for products that do not need extra processing after drying.

This is because it involves products that you directly fill into vials or other types of packages.

Further, it is possible to seal the vials within the lyophilizer, hence preventing potential contamination.

On the other hand, most people associate vacuum spray dryer with bulk instead of vial-based processing.

Nevertheless, it is a popular misconception that the drying machine is only appropriate for robust bulk pharmaceuticals and food products.

But, research show that it might be suitable for processing of some complex products.

For example, you can process nanoparticulates and microencapsulated bacteria.

Mini vacuum spray dryer

 Mini vacuum spray dryer

What is the Material Used to Make Vacuum Spray Dryer?

Stainless steel is the most common material used for making the main parts of the vacuum spray dryer.

The main components include collector, cyclone separator, spray chamber, and body.

Moreover, it has a borosilicate sight glass window that allows you to inspect the entire vacuum spray drying process.

Which Parameters does the Touch Screen PLC System of Vacuum Spray Dryer Control?

The design of the vacuum spray dryer makes sure that it is easy to choose and adjust all operations.

Ensuring simple operation allows you to quickly attain optimum conditions for vacuum spray drying.

Using PLC system, the touch screen display allows you to manage the following parameters:

  • Inlet Temperature
  • Air compressor flow
  • Pump speed
  • Airflow Volume
  • De-blocker Frequency.

What is the Role of De-blocker in Vacuum Spray Dryer?

The spray assembly integrates an automatic de-blocking gadget that prevents blockage of the spray nozzles.

An integral compressor activates the de-blocking needle.

De-blocker is necessary when feedstock might solidify or large particles lead to blockage of the spray nozzle.

Which are the Types of Nozzles used in Vacuum Spray Dryer?

The choice of the spray drying machine nozzle to use depends on the following factors:

Spray dryer nozzle

Spray dryer nozzle

  • Feedstock
  • Desired powder properties
  • Capacity and type of vacuum spray dryer
  • The capacity of the spray nozzle

Here are the common types of spray nozzles utilized in vacuum spray dryer:

· Rotary Atomizers

This type of atomizer utilizes power from a high-speed spinning wheel to separate the feed formulation into droplets.

You inject the feedstock at the wheel center and it flows across the surface to the circumference.

As the liquid leaves the wheel, it separates into droplets.

· Pressure Nozzle

These are the most popular types of atomizers used in vacuum spray dryers.

Pressure nozzles often develop coarser, more free-flowing particles than rotary atomizers.

They are also known as “vortex” spray nozzles since they incorporate functionality that promotes the whirling of fluid flowing across them.

Some designs utilize slotted cores or vanes to produce the vortex.

However, the drawback of the slotted nozzle design is that it is susceptible to blockage and untimely wear.

The whirling liquid enables the atomizer to transform the potential energy of formulation subjected to pressure to kinetic energy around the nozzle orifice.

It does this through the formation of a slim, high-speed layer around the spray nozzle exit.

While leaving the nozzle, the unsteady layer disintegrates, initially forming ligaments and then ultimately droplets.

You can use pressure nozzles over a wide flow rate range.

Moreover, it is possible to combine them in multiple nozzle installations giving high particle size flexibility and flow rate.

The scope of operating pressure for this type of spray nozzle varies from 250 PSI to 10,000 PSI.

· Two-Fluid Nozzle

This type of spray nozzle combines compressed air and liquid feedstock in a single nozzle.

It uses compressed air energy for atomization of the liquid suspension.

Two-fluid nozzles can atomize extremely viscous liquids, although they are very costly to run due to high compressed air costs.

Two main benefits of a two-fluid nozzle are the capability to atomize highly viscous fluids and to generate extremely fine particles.

They commonly find application in the pilot plant and laboratory vacuum spray dryer applications.

This is due to their capacity to generate a broad range of droplet sizes and flow rates.

Which are the Advantages of Rotary Atomizer of Vacuum Spray Dryer?

The three main advantages of using a rotary atomizer in vacuum spray dryer include:

  • The feed system can function at comparatively low pressure since the motor-driven wheel supplies the break-up energy.
  • Capable of handling vacuum spray drying in which clogging would present a challenge to the spray nozzles.
  • You can change the particle size by adjusting the speed of the wheel.

Why is it Important to Concentrate the Feedstock Before Introducing into Vacuum Spray Dryer?

Before introducing the feedstock into the vacuum spray dryer, you must concentrate it.

The concentration of feedstock helps in increasing the solid content.

This in turn reduces the quantity of liquid that the vacuum spray dryer must evaporate.

Which are the Different forms of Feedstock for Vacuum Spray Dryer?

One advantage of vacuum spray dryer is that it is possible to introduce any form of feedstock that you can pump:

  • Solutions
  • Slurries
  • Pastes Gels
  • Suspensions

Which are the Key Characteristics of Feedstock that you Must Consider when Using Vacuum Spray dryer?

The initial step in vacuum spray dryer is preparing the feedstock by optimizing its important characteristics:

· Feed Temperature

The feedstock temperature influences the viscosity and heat transfer from the heated air within the drying chamber to the fluid droplets.

Therefore, you must consider both the feedstock and chamber air temperature when choosing materials for the nozzle seal.

· Melting Temperature

Some type of feedstock for vacuum spray dryer is solid at room temperature.

Therefore, you need to melt it to facilitate atomization.

Spray cooling entails producing crystals/pellets through spraying molten feedstock within a dryer chamber having movement of cooling air.

· Abrasion

You must also consider the feedstock abrasiveness when choosing the materials for the interior components of the spray nozzle.

For most applications of vacuum spray dryers, tungsten carbide is the ideal material for orifice disks and swirls.

Tungsten carbide exhibits excellent abrasion resistance and good resistance to corrosion for most feedstock.

· Corrosion

Corrosive attack on the components of the vacuum spray dryer nozzle by some feedstock is a bigger issue than abrasion.

In such situations, you can use spray nozzles made using nickel alloy C22 or 316 stainless steel.

· Specific Gravity

This refers to feedstock density with respect to water.

A value higher than 1 implies that the raw material has a greater density compared to water.

Raising specific gravity of feedstock decreases the feed flow via the spray nozzle.

· Solids Content

Solid content represents the feedstock percentage that comprises of solids.

Majority of feedstock constitutes approximately 50 percent solids, however, the range varies from 20 to 70 percent.

Raising the solid content decreases the moisture quantity removed by the vacuum spray dryer.

As you increase the solid content, the pumping and atomization of feed gets more challenging.

· Surface Tension

This refers to the force exerted on the surface of fluid formulation that have the tendency of decreasing its surface area.

Decreasing the surface tension facilitates easier atomization of the feedstock.

· Viscosity

Viscosity of feed describes its resistance to flow.

Raising viscosity incline to increase size of the droplet.

Moreover, in some nozzle designs, increasing viscosity also increases the rate of flow.

Why is Bulk Density of Powder Important in Vacuum Spray Dryer?

Bulk density refers the dried powder weight/unit volume and forms a crucial parameter in majority of vacuum spray drying machines.

It dictates the fullness/size of packages and affects costs of handling and shipping.

You must constantly monitor the bulk density of powder during the process of vacuum spray drying.

Which are the Factors Affecting Bulk Density of Vacuum Spray Dryer?

Some of the factors influencing bulk density of powder produced by vacuum spray dryer include:

  • The increasing rate of feed raises bulk density when residuary moisture increases
  • When the increasing the temperature of feedstock results in spherical droplets production rather than threads, there will be an increase in bulk density.
  • In the case of easily atomized feedstock, the increasing temperature might lower bulk density.
  • The fine uniform powder features a higher bulk density compared to coarse uniform powder.
  • Powder having broad particle size distribution will feature higher bulk density compared to a powder having narrower sizes distribution.
  • Increasing solids in feedstock typically raise bulk density.
  • Aerating the feed of lowers the bulk density of powder.
  • Liquid suspensions provide higher bulk densities in comparison to liquid solutions.
  • Raising residuary moisture content raises bulk density.
  • Elevating the temperature of inlet air lowers powder bulk density.
  • The decreasing the temperature of outlet air raises residuary moisture level and hence increases powder bulk density.
  • Co-current vacuum spray drying machines generate powders having reduced bulk densities in comparison to counter-current types.

What is the Difference Between Products Produced in Vacuum Spray Dryer and Conventional Spray Dryer?

Let’s look at the key differences between products dried by conventional spray dryer and vacuum spray dryer:

Laboratory vacuum spray dryer

Laboratory vacuum spray dryer

· Moisture Content

The powder produced by the two spray dryer types exhibited considerable differences between them in terms of moisture.

Vacuum spray dryer produces particles with relatively higher moisture content than conventional spray dryer.

This is due to the high temperature of drying air in a standard spray drying machine.

Due to this fact, there is a larger difference in temperature between the drying air and sprayed product.

The great temperature differential leads to greater transfer of heat and a higher water evaporation.

As a result, it results in lower moisture content values.

Lack of a direct source of heat in vacuum spray dryer leads to high moisture content of the final dried powder.

Absence of sufficient heat to facilitate of entire water out of the product causes the higher moisture content.

· Apparent Density

Particles produced by vacuum spray dryer exhibited the lowest apparent density.

Particle size may be the reason for densities differences between particles produced by vacuum spray dryers and conventional spray dryers.

Smaller powder particles lead to higher apparent density.

This is because the agitation during spray drying tends to reduce the gap between particles.

This compels the powder to cover smaller volumes.

Moreover, you can as well link greater apparent density to reduced moisture content.

Since vacuum sprat dryer form particles with high moisture content, it leads to mot completely dried agglomerates.

As a result, it produces particles with lower apparent density.

However, conventional spray dryer forms powder having greater apparent density.

· Particle Size

The dried product produced by the two spray drying equipment differs considerably from one another in terms of mean diameter.

Particles produced by vacuum spray dryers have a larger diameter compared to those produced by an ordinary spray dryer.

The high temperatures of drying in conventional spray dryer led to smaller particles compared to those formed in vacuum spray dryer.

This could be due to higher evaporation of water in the products, leading to drier and finer particles.

However, in a vacuum spray dryer, the feedstock within the low-pressure drying chamber experiences reduced expansion due to low temperature.

This resulted in the production of larger particles.

Furthermore, the presence of higher moisture content as well leads to increase in particle diameter.

Particles with higher moisture content incline to agglomerate.

The atomizer type, solution viscosity, and feed solution viscosity as well as affect the particle size.

Atomized particle size depends directly on the solution viscosity during an atomization process at a consistent speed.

Solutions of higher viscosity lead to the formation of higher droplets during atomization of the vacuum spray dryer.

Consequently, this results in a greater amount and size of particles.

· Drying Process Yield

There exist a considerable difference in drying efficiency between the two spray drying machines.

Conventional spray dryer exhibit higher yield than vacuum spray dryer because of large material retention in the internal walls of the latter.

Application of high temperatures in traditional spray dryer leads to greater process yield.

You can attribute this to enhanced heat efficiency and mass transfer operations when you elevate the drying air temperature.

In a vacuum spray dryer, the material adhesion onto the drying chamber’s internal walls adversely affects process yield.

The feedstock material deposition is because of partial evaporation of moisture.

To boost process yield, you can install a heat supply system on the chamber’s inner walls.

For instance, you can integrate hot water flow within a jacket.

Moreover, boost water vapor suction movement by incorporating more vacuum pumps in the spray drying system.

What is the Shape of Powder produced by Vacuum Spray Dryer?

Most vacuum spray drying machines generate spherical particles though there are others that produce a non-spherical powder.

Moreover, the particles may be solid or hollow.

You characterize non-spherical particles by their aspect ratio, which refers to the longest dimension to the shortest dimension ratio.

How Does Viscosity Affect the Droplet Size and Flow Rate in Vacuum Spray Dryer?

As earlier explained, viscosity refers to the resistance to fluids flow, whose common measurement unit is the centipoise.

In most cases, an increase in viscosity tends to enlarge droplet size.

Furthermore, with spray nozzle designs, there tends to be an increased flow rate with increased viscosity.

What are the Factors to Consider When Selecting Vacuum Spray Dryer Nozzle?

Here are the essential considerations when choosing the spray nozzle of a vacuum spray dryer:

Spray dryer machine

 Spray dryer machine

  • Feedstock particle size, solid content, viscosity, and density
  • Vacuum spray dryer size, temperature, velocity, humidity and pressure
  • Required construction materials for corrosive environments
  • Required flow rate of spray media
  • Available pressure drop across the spray nozzle

Is there a Difference Between Droplets and Particle in Vacuum Spray Dryer?

Yes, there is significant difference between droplet and particle of vacuum spray drying equipment:

Droplet refers to a subdivision of the feedstock the dryer is spraying from the atomizer. Provided the spray comprises of surface moisture, you refer to it as droplets.

Particle refers to a subdivision of the final dried powder. The particle shape relies on how the vacuum spray dryer formed the droplets and its behavior during spray drying.

Depending on your unique requirements and specifications, we have a range of spray drying machines such as low-temperature spray dryers, benchtop spry dryer, ceramic spray dryer, pilot scale spray dryer, Nano spray dryer, organic solvent spray dryer, inert loop spray dryer, and small spray dryer.

Contact us now for all your vacuum spray dryer needs.

Send Inquiry Now!