IR and RF Dryers

infrared · RF · drying · coatings

Hot-air dryers heat air, then the surface, then wait for water to escape. Infrared heats the surface directly and radio frequency heats the water itself, which is why both beat gas ovens on time, footprint and energy.

Diagram of the electromagnetic spectrum from 1 kHz to 1 PHz showing where electric heating methods sit: induction from 1 kHz to 1 MHz for metals only; radio-frequency drying at the ISM frequencies 13.56, 27.12 and 40.68 MHz; microwave at 915 and 2,450 MHz; infrared from 0.75 to 1,000 micrometers. Below, how heat reaches the water: hot air heats the surface and moisture must diffuse out against the heat flow; infrared is absorbed near the surface, fast for coatings and thin webs; RF heats water through the whole thickness, and wet zones absorb the most. WHERE ELECTRIC HEATING SITS ON THE SPECTRUM 1 kHz 1 MHz 1 GHz 1 THz 1 PHz Inductionmetals only RF13.56-40.68 MHz Microwave915, 2,450 MHz Infrared0.75-1,000 µm HOW HEAT REACHES THE WATER Hot airHeats the surface; moisture diffuses out against the heat flow InfraredAbsorbed near the surface; fast for coatings and thin webs RFHeats water through the thickness; wet zones absorb most
RF bands
13.56 / 27.12 / 40.68 MHz
IR bands
Short, medium, long wave
Typical uses
Coatings, textiles, food
Companies tracked
11, 1 Chinese
Hub
Industry

Finding

Most industrial drying below 200 °C can move from gas to infrared or radio frequency today, and the barrier is integration cost, not physics

Infrared emitters convert most of their electrical input to radiant heat and suit thin films, inks, powder coatings and paper webs. Radio-frequency dryers drive the water molecules through the whole product, so thick textile packages, foundry cores, baked goods and timber dry from the inside out and moisture evens out instead of case-hardening.

Reported savings for RF and IR retrofits run 40-70% against convective hot air, and a hybrid hot-air plus RF line can cut drying time by about 60%. RF is the most capital-intensive option: each product shape needs its own electrode design, generators must stay inside the ISM bands allotted under FCC Part 18 and the ITU Radio Regulations, and shielding and interlocks are mandatory.

Combinations usually win. Infrared flashes off surface water or cures a coating, RF removes deep moisture, and a small air stream carries the vapor away. The same line runs on grid or on-site renewable power, which takes a natural-gas burner out of the plant's Scope 1 emissions.

Compare

IR, RF and hot air compared

The right choice depends on product thickness, moisture and whether the heat must stay at the surface.

Drying technologies compared
MethodHeating modeBest forLimits
Short-wave (near) IRSurface; emitter about 2,000-2,400 KPowder coat, inks, thin films, automotive paint repairLine of sight; dark and light surfaces absorb differently
Medium- and long-wave IRSurface; lower emitter temperatureWater-based coatings, paper, plastics formingSlower response; still surface-only
Radio frequency (RF)Volumetric; ISM bands 13.56-40.68 MHzTextile packages, foundry cores, post-bake biscuits, pasteurizing nuts and flour, woodCustom electrodes; highest capital cost
Hot-air convection (gas or electric)Surface; air as carrierBulk solids, low-value productsLarge ovens; heat must diffuse inward
Hybrid IR, RF and airSurface plus volumetricThick or wet products needing a dry surfaceMore complex control

Suppliers

Equipment makers

Infrared emitter and oven makers, then radio frequency and microwave dryer builders. Active companies first, then pilots, research groups and companies that exited.

Infrared emitters and dryers
CompanyProductsHQTechnologyStatus
AdphosNear-IR drying for coatings, coil and printGermanyNIR emittersactive
CeramicxCeramic long-wave IR emittersIrelandCeramic IR emittersactive
Fostoria Process HeatIndustrial IR ovens and heatersUSIR ovensactive
GlenroIndustrial IR heaters and dryersUSIR heatersactive
Heraeus NoblelightShort- and medium-wave IR emitters and systemsGermanyQuartz IR emittersactive
UshioIR halogen and UV lampsJapanHalogen IRactive
Radio frequency and microwave dryers
CompanyProductsHQTechnologyStatus
Radio Frequency Co.RF dryers and pasteurizersUSRF heatingactive
Shandong Loyal IndustrialMicrowave and RF dryers for food and chemicalsChinaMicrowave and RFactive
StalamRF dryers for textiles and foodItalyRF at 27.12 MHzactive
StrayfieldRF and microwave systemsUKRF and microwaveactive
Thermex-ThermatronRF and microwave heating systemsUSRF and microwaveactive

Sources

Sources and scope

Scope
Infrared and Radio-Frequency Dryers
Sources
Supplier disclosures; FCC Part 18; ITU Radio Regulations; published retrofit case studies
Updated
October 2026