Drying Equipment

VTD – Vacuum Tray Dryer

Mechotech designs and manufactures the VTD Vacuum Tray Dryer as turnkey process equipment for the static drying of solids under vacuum. Material is spread on trays and dried by conduction from heated shelves inside a sealed vacuum chamber, with no agitation, so the product is not mechanically disturbed. Mechotech’s photographs show a rectangular chamber with a stack of shelves, a large door with sight glasses and a vapour outlet leading to a condenser vessel. The unit is designed around the client’s product and target dryness, then fabricated, installed and commissioned by Mechotech as a single scope.

The VTD Vacuum Tray Dryer is built in SS 316L (or a process-appropriate grade) as a sealed chamber housing a stack of hollow, jacketed shelves; wet solid, cake or paste is spread in thin layers on trays that are loaded onto the shelves, and hot water, steam or thermic fluid circulated through the shelves conducts heat into the product. With the chamber under vacuum, moisture evaporates at a lower temperature and is drawn through a vapour outlet to a condenser, so drying takes place by static conduction and evaporation without stirring or tumbling the product. Electropolished product-contact surfaces, removable tray trolleys and PLC-based control of shelf temperature and vacuum support repeatable batch drying. Capacity is configured to the customer’s requirement, and the unit is delivered with documentation to support GMP qualification.

Process Flow

Mechotech VTD Vacuum Tray Dryer with the chamber door open, showing the stack of shelves inside the sealed vacuum chamber

Technical Specifications

Equipment Type	Vacuum Tray Dryer (VTD) — static, tray-based conduction drying under vacuum
Chamber Shape	Rectangular or cylindrical sealed chamber (configurable)
Construction	SS 316L (or process-appropriate alloy), electropolished product-contact surfaces
Shelf System	Hollow, jacketed shelves, fixed or on a removable tray trolley
Heating Medium	Hot water / steam / thermic fluid circulated through shelves
Agitation	None — static tray drying, no mechanical disturbance of product
Vacuum System	Vacuum pump with vapour outlet and external condenser
Inert Atmosphere Option	Nitrogen / inert-gas purge, where fitted, confirmed in design for the product
Loading Format	Removable trays on trolley or fixed shelf loading
Automation	PLC-based control of shelf temperature and vacuum level
Monitoring	Shelf / product temperature probes, vacuum gauging
Cleaning	CIP-capable chamber, removable trays for external cleaning
Capacity	Configured to requirement — small pilot chambers to larger multi-shelf production units
Utilities	Hot water / steam / thermic fluid for shelf heating, vacuum system utilities, nitrogen / inert gas (where fitted), electric power
Compliance	GMP hygienic design; full documentation for qualification

Plant Capacities

Chamber Scale	Typical Use	Loading Format	Shelf Count
Pilot-scale	Formulation and process-parameter trials	Fixed shelf or small trolley	Few shelves
Production-scale	Commercial batch drying	Tray trolley	Multi-shelf
Large production-scale	High-volume batch drying	Multiple tray trolleys	Multi-shelf, larger tray area

Shelf area, chamber volume and heating capacity are sized to the tray load and target drying time; no fixed areas or volumes are quoted on this page.

Manufacturing Process

Tray Loading

The wet solid, cake or paste is spread in a thin, even layer across trays, which are loaded onto a trolley or directly onto the chamber's fixed shelf stack.

Chamber Sealing

The loaded trays are wheeled or placed into the rectangular or cylindrical chamber, and the door is sealed to establish an airtight enclosure.

Vacuum Draw

The chamber is evacuated to the target vacuum level, lowering the boiling point of residual moisture so evaporation can proceed at a reduced temperature.

Shelf Heating (Conduction)

Hot water, steam or thermic fluid circulates through the hollow, jacketed shelves; heat conducts from the shelf into the tray and then into the static product layer resting on it.

Static Evaporation

Moisture evaporates from the exposed surface of the undisturbed product bed under vacuum, with no agitation, tumbling or mechanical contact of any kind.

Vapour Removal & Condensation

Evaporated moisture is drawn from the chamber through a vapour outlet to an external condenser, where it is recovered, sustaining the vacuum level through the cycle.

Endpoint Verification

Product or shelf temperature and vacuum-level trends are monitored, and trays can be sampled between cycles to confirm the target residual moisture has been reached.

Unloading & Cleaning

Trays are removed once dry, and the chamber and tray trolley are cleaned between batches, supporting validated changeover between products.

Major Plant Equipment

Sealed rectangular or cylindrical vacuum chamber (SS 316L, electropolished)
Hollow jacketed shelf stack
Removable tray trolley and trays
Chamber door with vacuum-rated seal
Heating system (hot water / steam / thermic fluid) with circulation pump
Vacuum pump and vacuum receiver
Vapour/solvent recovery condenser
Nitrogen/inert-gas purge system (where fitted)
Instrumentation (shelf/product temperature, vacuum level)
PLC-based control panel

Plant Output

Dried solid (granules, crystals or powder)Dried cake or block form (pre-milling)Recovered process solvent (via condenser)

Applications

Drying of friable granules and crystals where mechanical disturbance is undesirable
Drying of botanical and herbal extracts at reduced temperature
Nutraceutical powder and granule batch drying
Drying of filter cakes where agitation would damage the product form
Food-grade solid drying requiring undisturbed handling
Vacuum drying of solvent-wet solids with solvent recovered in a condenser
Small-batch and multi-product drying with tray-trolley changeover

Key Features

Static, Non-Agitated Drying
The product rests on trays throughout the cycle, so there is no paddle or tumbling action on the material.
Low-Temperature Vacuum Drying
Under vacuum the boiling point of moisture falls, so evaporation proceeds at a lower shelf temperature.
Inert-Gas Purge Option
A nitrogen or inert-gas purge can be fitted and is confirmed in design for products that need it.
Removable Tray Trolleys
Trays on a removable trolley can be loaded and unloaded outside the chamber, which shortens the time the chamber is open.
Solvent Recovery via Condenser
A condenser on the vacuum line recovers solvent evaporated during drying.
SS 316L, CIP-Capable Construction
Electropolished SS 316L surfaces, removable trays and a cleanable chamber support GMP hygienic design.

Frequently Asked Questions

Does Mechotech supply the complete VTD Vacuum Tray Dryer?

Yes. Mechotech is a process equipment manufacturer and supplier, engineering and fabricating the complete VTD Vacuum Tray Dryer at our Hyderabad facility, installing and commissioning it as a single integrated system, with documentation to support GMP qualification. Final parameters are established during process development and pilot validation.

What capacities are available for the VTD Vacuum Tray Dryer?

Mechotech builds the VTD Vacuum Tray Dryer from pilot units for process validation to larger commercial installations. Vessel or unit size, duty and ancillaries are configured to the confirmed throughput or batch size; we recommend a pilot unit to validate parameters before scaling.

Which industries use the VTD Vacuum Tray Dryer?

The uses listed on this page are given under Applications. The industry, the feed and the target output are confirmed with the client before the equipment is configured.

What is a Vacuum Tray Dryer (VTD) used for?

A VTD dries wet solids, cakes or pastes spread on heated trays inside a sealed vacuum chamber, using conduction from the heated shelves and reduced-pressure evaporation, with no agitation. It is chosen where the product should not be mechanically disturbed during drying.

Why is a static (non-agitated) dryer preferred for some products?

Some crystalline, granular or fragile products can be damaged by the tumbling or paddle action of an agitated dryer. In a VTD the product sits on the trays and is not stirred, so the drying step does not work the particles mechanically.

How does vacuum improve drying compared with atmospheric tray drying?

Vacuum lowers the boiling point of the moisture or solvent in the product, so evaporation proceeds at a lower shelf temperature than at atmospheric pressure, and for solvent-wet solids the evaporated solvent can be condensed and recovered.

Can a VTD be purged with inert gas?

The chamber is sealed, and a nitrogen or inert-gas purge can be fitted. Whether it is needed, and the area-classification requirements for a flammable-dust or flammable-solvent product, are confirmed with the client in design.

How is the VTD loaded and unloaded?

Trays are typically mounted on a removable trolley that is loaded outside the chamber and wheeled in as a unit, or loaded directly onto fixed shelves, depending on the configuration.

How does the VTD differ from agitated vacuum dryers like the RVPD or Vacuum Paddle Dryer?

The VTD dries product statically on trays, whereas the RVPD and the Vacuum Paddle Dryer use internal paddles to keep the product moving. The feed, its caking tendency and its sensitivity to mechanical handling decide the choice.

What information is needed to specify a VTD Vacuum Tray Dryer?

To configure the equipment Mechotech needs the wet feed and its moisture or solvent content, the maximum product temperature, the bulk density and layer depth on the tray, the batch size, the target dryness, whether solvent must be recovered and whether inert-gas purge is wanted, and the hygiene and documentation requirements. A pilot unit is recommended before scaling.

Which related drying pages does Mechotech list?

See the Vacuum Paddle Dryer, RVPD Rotary Vacuum Paddle Dryer, RCVD Rotary Cone Vacuum Dryer, FBD Fluidised Bed Dryer, Freeze Dryer / Lyophiliser and Spray Dryer. The hub is Drying Equipment Plants.

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VTD – Vacuum Tray Dryer