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Vacuum Shelf Dryer

Hywell Machinery is the lead manufacturer and factory of the vacuum shelf dryer. The vacuum shelf dryer is a vacuum tray dryer working under vacuum conditions. The vacuum shelf dryer dries on the conduction principle. There are several shelves inside the vacuum shelf dryer on which the product-laden trays are placed. The shelf is a pipe shelf to ensure proper heating of the tray.
Industrial vacuum shelf dryers are suitable for drying heat-sensitive raw materials that can decompose or polymerize or deteriorate at high temperatures. Industrial vacuum tray dryers are widely used in the pharmaceutical, chemical, foodstuff, and electronic industries.

  • FZG


  • 8419399090

  • SUS304/SUS316L

  • Food/Pharmaceutical/Chemical


Vacuum Shelf Dryer Introduction

Vacuum Shelf Dryers Consist of a square or round vacuum chamber with customized fixed internal shelves; the wet material to be dried is loaded into pans or trays and manually placed on the shelves. The top part of each shelf is flat with a coil jacket on the underside to circulate steam or liquid heating medium for the desired operating temperature. 

Due to hundreds of various types of products and demands of inducing and controlling a vacuum environment, almost all aspects of a vacuum shelf dryer's mechanical design and ancillary support equipment can be customized to meet each individual process design needs.

The overall dimension of each vacuum chamber is driven by the required shelf surface area for drying. The shelf size, spacing between each shelf, and selected chamber geometry (square or round) will determine the overall chamber size.

Delicate, heat-sensitive materials are dried safely at extremely low drying temperatures. Operating under a vacuum, the product is protected from oxidation and atmospheric contamination, and released solvents are fully recovered.

Vacuum Shelf Dryers are specified for products requiring uniform, low-temperature drying with no agitation or compression. Among those products are pharmaceuticals, nutraceuticals, vitamin extracts, specialty food items, fine chemicals, and glandular products.

Hywell machinery company is a professional Vacuum Shelf Dryer manufacturer that has two types of disc vacuum dryers; one is a square tray type vacuum dryer and the other is a circular vacuum dryer. The round shape vacuum shelf dryer cannot load too many trays, so it is more suitable for drying less material per batch.  Specific using circular shape vacuum dryers or square shape vacuum dryers, Hywell machinery's engineer will give recommendations according to material characteristics and single batch capacity.

Because the drying speed of the vacuum shelf dryer is relatively slow, if it needs a faster drying speed or liquid with high sugar content, it can consider Hywell company's high-efficiency vacuum dryer. The drying speed of the high-efficiency vacuum dryer is more than 4 times that of the ordinary vacuum tray dryer. Vacuum tray dryer can be used to dry liquids that high speed centrifugal spray dryer cannot dry, such as pasty liquids with high sugar content.

Sqaure vacuum dryer

Sqaure vacuum dryer

Round vacuum dryer

Round vacuum dryer

GMP Vacuum Shelf Dryer Video

Vacuum Shelf Dryers Description

FZG Series Vacuum Shelf Dryers are also named the Vacuum Tray Dryers or vacuum drying oven, The same equipment is called differently. the vacuum tray dryer uses a vacuum pump to damp air out from the interior of the machine and make the working chamber form vacuum status. and let the raw material be dried at vacuum condition, Therefore, the drying speed of raw material is improved and the energy is saved greatly. Because the raw materials load inside the tray (standard tray size:640x460x45mm that same as hot air tray dryer, it also can design nonstandard vacuum tray dryer), so the vacuum tray dryers are static vacuum drying machine, the form and structure of material can't be damaged when being dried. About the heating way of a vacuum tray dryer, it can use hot water, steam, or conduct oil. The exact heating way will be determined by the client's workshop heat source situation. because the interior of the machine is vacuum state. The temperature control is not accurate if testing the vacuum air temperature. So we have two ways to dissolve this issue. It can use a soft cable temperature sensor to test the material's temperature or the client adjust the heat source temperature.

Vacuum Shelf Dryer Interior Video

Vacuum Shelf Drying Machine Specifications


Layer of shelf

Qty of tray

Tray size (mm)

Vacuum pump power(kw)







































1. Accept non-standard customized vacuum drying oven

1. Hywell machinery reserves the right to the design without notice

2. All specifications of vacuum drying oven are as accurate as is reasonably possible, but they are not binding.

Vacuum shelf oven advantages

Hywell machinery FZG series vacuum shelf oven had the following advantages over conventional solutions.

1.    Vacuum shelf ovens have predictable and repeatable results.

2.    Dry Temperature Sensitive Products - Because all liquids vaporize at a lower temperature at reduced pressures, a vacuum shelf oven is possible to vaporize the liquids at very low temperatures.

3.    Reduced Energy – Since the evaporation of the liquid under vacuum occurs at a much reduce temperature, the temperature differential is increased without raising the temperature.

4.    Single Enclosed Environment – Active pharmaceutical ingredients, drugs, and toxic chemicals are easily isolated in a vacuum dryer. The closed system of the vacuum shelf drying oven also assures the maximum collection of solvents is achieved, protecting operators and the environment.

5.    Avoid Oxidation – vacuum shelf drying oven is ideal for avoiding oxidation of chemicals and with the addition of an inert gas purge, an oxygen-free environment can be maintained.

6. The heat source for evaporation may be low-pressure steam or surplus heat steam. but the vacuum shelf drying oven also can use hot water or thermal oil as the heat source. If the client has no heat source. we can design and supply the electrical heating thermal oil or hot water to supply the heat source for the FZG Vacuum Drying Machine.

7. It belongs to a static vacuum dryer. The materials load inside the tray, So the shape of the raw material to be dried should not be destroyed.

8. Highly polished inner and outer surfaces of the vacuum shelf drying machine, no dead comer, easy to clear, no cross-contamination. Confining the requirement of GMP.

Industrial Vacuum Dryers Application:

Industrial vacuum tray dryers are suitable for drying heat-sensitive raw materials that can decompose or polymerize or deteriorate at high temperatures. Industrial vacuum tray dryers are widely used in the pharmaceutical, chemical, foodstuff, and electronic industries. Particularly Industrial vacuum tray driers are suitable for row materials that have the following requirements:

1. Thermal-sensitive raw materials that cannot be dried at high temperatures.

2. Raw materials that are easy to oxidize and dangerous.

3. Raw materials that solvent and toxic gases are needed to recover.

4. Raw materials that have special requirements for crystal shape.

5. Raw materials that have special requirements for the content of residual volatile.

Tray Type Vacuum Dryer Rack

 The drying rack of the tray type vacuum dryer use to load the baking tray; this drying rack not only holds the tray and also transfers heat directly to the baking tray of the tray vacuum dryer. The interior of the rack is hollow, and the steam or hot water passes through the rack and transfers heat to the tray. Hywell machinery tray type vacuum dryer has two types of racks. one is a round tube type and the other is a plate type rack.

Round Pipe Drying Rack of Tray Type Vacuum Dryer


The round model drying rack is made of seamless steel pipe, and the steam or hot water passes through the round pipe and transfers the heat to the drying tray and the interior of the whole vacuum drying machine to dry the material.

Because the round tube drying rack is composed of some seamless steel pipes, there is a distance of 5-10 cm between each round tube, so when the baking tray is placed on the drying rack. The place of touches the baking pan dries significantly faster than the place where it is not grounded. Some special materials cannot accept this kind of not uniform drying. Hywell machinery's engineers designed the cheapest solution for this issue. it uses an independent baking tray support frame that is put on the drying rack, and separates the baking tray to directly contact the round tube. the support frame use to solve the not uniform drying.

Plate Type Rack of Tray Type Vacuum Dryer

    The new type of drying rack has a flat surface and automatic constant temperature, which ensures that the materials in the baking tray are heated evenly. The drying rack is composed of heating plates, pillars, and imported silicone tubes, with a beautiful appearance and easy maintenance. The hot water or steam passes through the inside of the rack to transfer heat. Because the outer area of the plate drying rack is much larger than the round tube rack, the heat transfer rate is also much higher than the round tube rack. and the plate drying rack is very flat, so it is directly and completely in contact with the drying tray, which speeds up the transfer of heat to the area, and the overall plate drying rack is more efficient than the round tube drying rack and has a faster drying speed. But the price of the plate rack is higher.

plate rack of vacuum dryer

Plate rack of vacuum dryer

tube rack of vacuum dryer

Tube rack of vacuum dryer

Heating method of vacuum dryer oven

For the heating method of the vacuum dryer oven, it can use steam or hot water or heat transfer oil as a heat source. However, the above heat sources cannot be provided by the end user. Hywell machinery can provide electric heating heat transfer oil furnace or electric heating hot water tank. Specific the vacuum dryer oven can be designed according to customers.

Condensation Recovery Unit of Vacuum Drying Oven

   If the material contains a large number of solvents such as methanol, ethanol, etc. The solvent of raw material can be collected by using a condenser. But the condenser of a vacuum drying oven to recollected the solvent that needs the user to supply cooling water, If the solvent is water or a low proportion of solvents, the condenser is not required in order to save investment cost.

Tube model condenser of vacuum dryer oven

There are two types of vacuum dryer oven condensers in Hywell company. One is the traditional tube condenser. This condenser is made of seamless steel pipes that are arranged inside the condenser cover. The outside of the tube is equipped with cooling fins to increase the condensation efficiency.

Hose wound tube condenser of vacuum dryer oven

The other is a metal hose condenser. The condenser of a vacuum dryer oven is undoubtedly a seamless metal hose wrapped inside the condenser. so the same heat exchange area, the outside size of the hose wound condenser is smaller than the tube condenser and the cost is also cheaper. now Hywell company almost use this kinds hose wound tube condenser.

Hose wound condenser

Hose wound condenser

mixing vacuum dryer

Tube model condenser

Vacuum Oven Dryer Construction Material

Hywell Machinery is able to offer our FZG series vacuum oven dryer with contact parts to be built in SS304, SS316L, Titanium, Duplex stainless steel, etc. Electrical parts of the vacuum oven dryer can be adapted to the customer’s needs.

How do the vacuum tray dryers works

Pure water has the maximum vaporization rate when it is boiling. Under normal conditions, pure water starts to boil at about 100°C. Under vacuum conditions, because the partial pressure of water vapor in the system is much lower than the partial pressure of water vapor on the surface of the material, the boiling point of water is lower than 100°C. For example: when the surface drops to -0.07MPa, the water starts to boil at 70°C. So despite the lower operating temperature, the vacuum tray dryers still have a larger drying capacity.

Vacuum shelf drier options

1.  Construction Material & Sanitary Finishes:

Hywell are able to offer the square vacuum shelf drying machine with contact part to be built in Carbon steel, SS304, SS316/316L, Titanium, Duplex stainless steel, etc. Standard of internal and external finish can be adopted to the customer’s needs.

2.  Heating & Cooling Jackets:

Square vacuum shelf drying machine are available with jackets for heating / cooling operation.

3.  Custom Engineered Dimensions:

Dimensions of the square vacuum shelf drying machine can be defined according to customer's requirements.

4.   Vacuum Drying Equipment Sizes:

Vacuum shelf Drying Equipment that can load tray from 10 to 120. Total the volume of the vacuum drying equipment with bigger size as per request &. more.

5. Industrial Vacuum Dryers Electrical Component 

industrial vacuum dryers can use international brand such as ABB ,Siemens or Schneider.

shelf vacuum dryer

Main machine

heating water tank

Heat + Vacuum system

Vacuum Shelf Dryer Video


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