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Vacuum Technology · PRBD & PVRD Series

Vacuum Ribbon Mixers & Dryers

Q: At what temperature does a vacuum dryer dry product?

At 10-100 mbar absolute pressure water boils between 7 and 46 degrees C, so most products dry at 30-50 degrees C product temperature.

Q: What final moisture can a vacuum ribbon dryer reach?

Below 0.1% w/w on most products, and single-digit ppm moisture for battery-grade materials under deep vacuum with nitrogen back-fill.

Q: Can solvents be recovered instead of vented?

Yes. A closed-loop condenser, receiver and cold trap recover solvents as liquid for reuse - standard for API, NMP and specialty chemical duties.

Q: What does a vacuum mixer/dryer replace?

A separate mixer, a tray or fluid-bed dryer, and the product transfer between them.

Pull the vessel down to 10–100 mbar absolute and water boils between 7 °C and 46 °C. That single fact is why a vacuum ribbon mixer/dryer can strip moisture or solvent from a heat-sensitive product at jacket temperatures a conventional dryer cannot approach — while the ribbon keeps the bed turning so every particle sees the heated wall and no crust forms.

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Annotated schematic of a QuantumX PRBD vacuum ribbon mixer dryer — counter-current ribbons, ASME jacket, vapour port and bomb-bay discharge — PRBD Series · Annotated schematic

10 – 200 mbarVacuum Range

< 0.1% w/wFinal Moisture

4 – 12 kg/m²·hEvaporation Rate

2 – 12 hCycle Time

01 · Principle

Lower the Pressure, Lower the Boiling Point

Absolute Pressure	Water Boils At	Typical Use
1013 mbar	100 °C	Atmospheric reference
200 mbar	60 °C	Light de-dusting, degassing
100 mbar	46 °C	Food powders, botanicals
50 mbar	33 °C	Proteins, enzymes, probiotics
20 mbar	18 °C	APIs, solvent recovery
10 mbar	7 °C	Battery materials, deep drying

One Vessel, Three Duties

Mix, react or wet-granulate, then dry to final moisture without transferring product. Fewer transfers means less exposure, less loss and no re-segregation between steps.

Vapour Recovery

Shell-and-tube or plate condenser, receiver and cold trap sized to the evaporation duty. Solvents are recovered as liquid for reuse rather than vented.

Oxygen-Free Processing

Evacuate and back-fill with nitrogen for oxidation-sensitive or dust-explosive products. ATEX execution and inert-loop control available.

Saturation temperature of water. Solvent systems follow their own vapour-pressure curve — specify the solvent at enquiry.

02 · Applications

Where Vacuum Mixing and Drying Is Used

Vacuum earns its capital wherever the product is worth more than the energy, degrades with heat, or carries a solvent that has to come back.

Pharmaceutical & API

Wet granulation followed by in-vessel drying to target LOD. Solvent recovery under closed loop, containment to OEB levels, full CIP and validation documentation.

10 – 30 mbar · Jacket 40 – 60 °C

Nutraceutical & Protein Powders

Drying botanical extracts, probiotics and whey or plant protein isolates without denaturation or loss of viable count. Colour and aroma retained.

30 – 80 mbar · Product ≤ 45 °C

Food & Beverage

Flavour and seasoning bases, instant powders, fruit and vegetable powders, pet-food premixes. Cook under jacket, flash-cool under vacuum, discharge stable.

50 – 150 mbar · Cook & Chill

Battery & Energy Materials

Cathode and anode precursor drying to single-digit ppm moisture, NMP and solvent recovery, electrode slurry pre-mix. Inert atmosphere throughout.

≤ 10 mbar · N₂ Back-fill

Specialty Chemicals

Pigments, catalysts, resins and intermediates. Reaction under vacuum with controlled heat input, then dry and cool in the same body. Hastelloy and titanium available.

10 – 100 mbar · Solvent Recovery

Plastics, Polymers & Minerals

Drying and degassing of resins, masterbatch and additive blends before extrusion; moisture control in technical ceramics and fine mineral powders.

50 – 200 mbar · Jacket to 150 °C

03 · Thermal

Temperature Control: Heating, Cooling, Vacuum

In a powder bed, conduction is slow and the product only heats where it touches metal. A jacketed ribbon mixer solves that by constantly renewing the layer at the wall — the agitator is the heat-transfer device as much as the jacket is. Add vacuum and you gain a second, independent control: the boiling point itself.

Heating

Steam, thermal oil or electrically heated fluid through a dimpled, half-pipe or limpet-coil jacket on trough and end plates. Hollow-shaft and hollow-ribbon execution adds interior heating surface where duty demands it.

Steam to 150 °C · Oil to 250 °C · Electric to 200 °C

Cooling

Chilled water or glycol through the same jacket circuit. Used to pull cooked product down to a safe packing temperature, to remove frictional heat from long mixes, and to hold exothermic reactions inside their window.

Chilled water to 4 °C · Glycol to −20 °C · CO₂ optional

Vacuum as Thermal Control

Lowering pressure lowers the boiling point, so moisture leaves at a temperature the product can survive. It also removes the entrained air that insulates particles, which measurably improves wall-to-bed heat transfer.

10 – 200 mbar · Boiling point 7 – 60 °C · Flash-cooling

Jacket Construction & Control

ASME-certified jackets rated to 6 bar (90 PSI); dimple, half-pipe or limpet coil selected by duty and fluid
Hollow shaft and hollow ribbon options raise heat-transfer area per litre by up to 45%
Jacket zoning on trough, end plates and doors so the whole wetted wall is active, not just the barrel
Product RTDs in the bed, not only in the jacket — control on product temperature
PLC recipe control of ramp, soak, cool and vacuum set-points with batch data logging
Rock-wool or aerogel insulation with stainless cladding; surface held below 60 °C for operator safety

Cook & Chill in One Vessel

Ready meals, sauces, soups, pet food and confectionery bases are cooked to temperature under steam, held, then cooled to packing temperature on the same circuit — no transfer, no second vessel, and a documented thermal record for the lot.

Also available without vacuum.

Ribbon mixers are also built as standard atmospheric mixers — the same engineered geometry, jacket options and trial validation, without the vacuum train. Specify at enquiry.

04 · Comparison

Ribbon Mixer vs. Vacuum Ribbon Mixer/Dryer

The vacuum machine is the same ribbon geometry inside a pressure-rated, jacketed body with a vapour system attached. It costs more and it does more. This table is where the line falls.

Attribute	Ribbon Mixer · PRB / PVR	Vacuum Mixer/Dryer · PRBD / PVRD
Primary duty	Blending to uniformity	Blending plus drying, degassing or reaction
Operating pressure	Atmospheric, optional light purge	10 – 200 mbar absolute
Vessel construction	Open-top trough or tank, gasketed cover	Pressure/vacuum-rated body, full-penetration welds
Jacket	Optional	Standard, ASME to 6 bar
Shaft sealing	Packed gland or air purge	Double mechanical seal, vacuum-rated
Ancillaries	Feeders, dust filter	Vacuum pump, condenser, receiver, cold trap, filter
Moisture removal	None	To below 0.1% w/w, product-dependent
Solvent recovery	Not applicable	Closed-loop condensation and reuse
Heat-sensitive product	Handled by cooling only	Dries at 30 – 50 °C product temperature
Oxidation / dust risk	Managed by inert purge	Evacuate and N₂ back-fill; inherently oxygen-free
Cycle time	3 – 20 min	2 – 12 h including drying
Installed power, 1,000 L	11 kW	18.5 kW plus vacuum skid
Relative capital	Baseline	2.5 – 4× baseline, ancillaries included
Replaces	—	A separate mixer, tray/fluid-bed dryer and the transfer between them
Choose it when	The product arrives dry and leaves dry	Moisture, solvent, oxygen or heat sensitivity is part of the specification

05 · Specifications

Horizontal Vacuum Ribbon Mixers/Dryers · PRBD Series

Dimensions in mm and exclude the vacuum pump, condenser and receiver skid. kW and RPM shown are for jacketed vacuum execution and vary with product viscosity and drying duty. Mixers can be built to a total volume of up to 30,000 L.

Model	Total L	Work. 40%	Work. 60%	kW	RPM	L	W	H	kg
PRBD-5L-CP	5	2	3	1.1	256	950	900	610	140
PRBD-10L-CP	10	4	6	1.1	256	1,050	900	610	160
PRBD-15L-CP	15	6	9	2.2	196	1,150	1,000	640	180
PRBD-20L-CP	20	8	12	2.2	196	1,250	1,050	670	210
PRBD-30	30	12	18	3	86	940	950	1,130	330
PRBD-45	45	18	27	3	86	940	1,000	1,160	340
PRBD-50	50	20	30	4	77	1,000	1,050	1,200	460
PRBD-60	60	24	36	4	77	1,000	1,100	1,200	590
PRBD-70	70	28	42	4	60	1,150	1,130	1,250	720
PRBD-100	100	40	60	4	60	1,410	750	1,650	780
PRBD-150	150	60	90	5.5	56	1,450	800	1,680	810
PRBD-200	200	80	120	5.5	49	1,590	810	1,710	850
PRBD-250	250	100	150	7.5	46	1,750	850	1,750	910
PRBD-300	300	120	180	7.5	46	1,825	865	1,760	980
PRBD-400	400	160	240	11	42	1,900	950	1,900	1,110
PRBD-500	500	200	300	11	42	2,010	1,020	2,020	1,240
PRBD-600	600	240	360	15	42	2,200	1,050	2,090	1,370
PRBD-700	700	280	420	15	42	2,300	1,070	2,100	1,500
PRBD-750	750	300	450	15	42	2,355	1,110	2,150	1,630
PRBD-800	800	320	480	18.5	36	2,400	1,150	1,765	1,760
PRBD-1000	1000	400	600	18.5	28	2,500	1,200	1,765	1,890
PRBD-1200	1200	480	720	22	28	2,650	1,250	1,800	2,080
PRBD-1500	1500	600	900	22	28	2,850	1,300	1,870	2,210
PRBD-2000	2000	800	1200	22	25	3,020	1,400	1,980	2,930
PRBD-2500	2500	1000	1500	30	25	3,200	1,500	2,100	3,380
PRBD-3000	3000	1200	1800	30	25	3,400	1,550	2,150	3,640

Vertical Vacuum Ribbon Mixers/Dryers · PVRD Series

Dimensions in mm and exclude the vacuum skid. Working volumes at 30% and 70% of total.

Model	Total L	Work. 30%	Work. 70%	kW	RPM	Dia.	H	kg
PVRD-15	15	4	10	1.5	92	450	1800	180
PVRD-20	20	6	14	1.5	77	550	2100	240
PVRD-30	30	9	21	2.2	77	550	2100	340
PVRD-45	45	14	32	2.2	68	655	2200	420
PVRD-50	50	15	35	2.2	68	655	2200	480
PVRD-60	60	18	42	2.2	66	720	2200	540
PVRD-70	70	21	49	3	65	720	2200	660
PVRD-100	100	30	70	3	59	720	2200	720
PVRD-150	150	45	105	4	53	875	2500	840
PVRD-200	200	60	140	4	48	875	2500	960
PVRD-250	250	75	175	5.5	45	980	2200	550
PVRD-300	300	90	210	5.5	43	980	2200	590
PVRD-400	400	120	280	7.5	37	1160	2400	650
PVRD-500	500	150	350	7.5	37	1160	2400	720
PVRD-600	600	180	420	7.5	34	1500	2600	910
PVRD-700	700	210	490	11	33	1500	2600	1070
PVRD-750	750	225	525	11	33	1500	2600	1240
PVRD-800	800	240	560	11	30	1500	2600	1370
PVRD-1000	1000	300	700	15	28	1525	3000	1430
PVRD-1200	1200	360	840	15	26	1680	3200	1560
PVRD-1500	1500	450	1050	18.5	25	1680	3200	1690
PVRD-2000	2000	600	1400	22	25	1860	3600	1890
PVRD-2500	2500	750	1750	22	20	2000	3700	1950
PVRD-3000	3000	900	2100	30	20	2080	3900	2080
PVRD-4000	4000	1200	2800	37	20	2300	4100	3320

Gallery

In the Shop & In the Field

FAQ

Vacuum Drying Questions, Answered

At what temperature does a vacuum dryer dry product?

At 10–100 mbar absolute pressure, water boils between 7 °C and 46 °C — so most products dry at 30–50 °C product temperature. Heat-sensitive materials such as proteins, probiotics and APIs retain activity, colour and aroma.

What final moisture can a vacuum ribbon dryer reach?

Below 0.1% w/w on most products, and single-digit ppm moisture for battery-grade materials under deep vacuum with nitrogen back-fill. Evaporation rates typically run 4–12 kg/m²·h with cycle times of 2–12 hours including drying.

Can solvents be recovered instead of vented?

Yes. A closed-loop vapour system — condenser, receiver and cold trap sized to the evaporation duty — recovers solvents as liquid for reuse. This is standard practice for API, NMP and specialty chemical duties.

What does a vacuum mixer/dryer replace?

A separate mixer, a tray or fluid-bed dryer, and the product transfer between them — along with the exposure, loss and re-segregation that transfer causes. One vessel handles mixing, reaction or granulation, drying and cooling.

Moisture, Solvent, Oxygen or Heat Sensitivity in Your Spec?

Then the vacuum execution earns its capital. Send us the product, the target LOD and the solvent — we'll size the vessel, the jacket and the vapour system, and prove the cycle in trial.

Discuss Your Drying Application