Drying Equipment

VTD – Vacuum Tray Dryer

Mechotech engineers and manufactures the VTD Vacuum Tray Dryer as turnkey process equipment for pharmaceutical, nutraceutical, food, and botanical processing lines that need static, low-temperature drying of heat-sensitive, friable or explosive-dust solids. Material is spread on heated trays inside a sealed vacuum chamber and dried purely by conduction and reduced-pressure evaporation, with no agitation or mechanical disturbance at all, making it the standard choice wherever a product's physical form must be preserved through drying.

The VTD Vacuum Tray Dryer is built in SS 316L (or a process-appropriate grade) as a rectangular or cylindrical sealed chamber housing a stack of hollow, jacketed shelves; wet solid, wet 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 hollow shelves conducts heat directly into each tray, which in turn conducts it into the product resting on it. With the chamber evacuated to vacuum, moisture evaporates at a reduced temperature and is drawn off through a vapour outlet to a condenser, so drying takes place entirely by static conduction and evaporation — the material is never stirred, tumbled, or mechanically worked, which protects friable granules, crystals, and fragile particulate structures from attrition and keeps dust-generating or oxygen-sensitive products safely contained within a sealed, inert-gas-capable chamber. Electropolished product-contact surfaces, removable tray trolleys for fast loading and unloading, and PLC-based control of shelf temperature and vacuum level support repeatable batch drying, and capacity is configured to the customer's requirement from small pilot chambers to larger multi-shelf production units.

Process Flow

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 capability for oxygen-sensitive or flammable-dust products
Loading Format	Removable trays on trolley (bulk loading/unloading) 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 / WHO-GMP / Schedule M hygienic design

Plant Capacities

Chamber Scale	Typical Use	Loading Format	Shelf Count
Pilot-scale	Formulation & 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; exact capacity is configured to your batch size and product's moisture profile.

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, product-safe 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 pharmaceutical granules and crystals without attrition
Drying of heat-sensitive botanical and herbal extracts
Drying of explosive or flammable dusts requiring inert-atmosphere handling
Nutraceutical powder and granule batch drying
Drying of filter cakes where agitation would damage product form
Food-grade solid drying requiring gentle, undisturbed handling
Vacuum drying of solvent-wet crystalline products for solvent recovery
Small-batch and multi-product pharmaceutical drying with fast changeover

Key Features

Fully Static, Non-Agitated Drying
Product rests undisturbed on trays throughout the cycle, so friable granules, crystals and fragile particulate structures are dried without attrition or mechanical damage.
Low-Temperature Vacuum Drying
Operating under vacuum lowers the boiling point of moisture, allowing gentle, reduced-temperature drying that protects heat-sensitive botanical and pharmaceutical actives.
Inert-Atmosphere Capable
The sealed chamber can be purged and held under nitrogen or inert gas, suiting oxygen-sensitive materials and products that generate flammable or explosive dust.
Removable Tray Trolleys for Fast Loading
Trays mounted on a removable trolley can be loaded and unloaded away from the chamber, minimising chamber downtime between batches.
Solvent Recovery via Condenser
A condenser on the vacuum line recovers solvent evaporated during drying, supporting economical processing of solvent-wet crystalline products.
GMP-Compliant, CIP-Capable Construction
Electropolished SS 316L surfaces, removable trays and a cleanable chamber meet WHO-GMP and Schedule M hygienic-design expectations for regulated batch manufacturing.

Frequently Asked Questions

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 only conduction from the heated shelves and reduced-pressure evaporation — with no agitation at all. It is chosen for friable, heat-sensitive, or explosive-dust products whose physical form must be preserved through drying.

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

Some crystalline, granular or fragile products are damaged by the tumbling or paddle action used in agitated dryers. Because the VTD never mechanically disturbs the product — it simply sits on heated trays under vacuum — particle size, crystal form and physical structure are preserved through the drying cycle.

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 much lower shelf temperature than atmospheric drying would require. This protects heat-sensitive actives and, for solvent-wet solids, allows the evaporated solvent to be condensed and recovered.

Can the VTD handle flammable or explosive dusts?

Yes. The chamber is fully sealed and can be purged and held under nitrogen or another inert gas, which is important for products that generate flammable or explosive dust, or that are sensitive to oxidation during drying.

How is the VTD loaded and unloaded?

Trays are typically mounted on a removable trolley that can be loaded with wet product outside the chamber and then wheeled in as a complete unit, minimising the time the chamber itself is open and reducing turnaround time between batches.

What capacity range is available?

Chamber volume, shelf area and heating capacity are configured to your tray load and target drying time, from small pilot chambers used for formulation trials up to larger multi-shelf production units for commercial batch manufacturing.

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

The VTD dries product statically on trays with no moving parts in contact with the material, which suits friable or attrition-sensitive solids. The RVPD and Vacuum Paddle Dryer instead use internal paddles to continuously agitate the product, which speeds drying and prevents caking on sticky pastes but is not appropriate where mechanical disturbance would damage the product.

Ready to discuss your project?

Get a free quote and technical consultation from our engineering team.

Get A Free Quote

VTD – Vacuum Tray Dryer