Service (Selection Aids, User Manual, Infrared Research)

Service tools and research knowledge on the selection and use of infrared heaters

Heating with infrared radiation is a complex issue. A higher emitter temperature does not always mean a faster heating. Matching the emitter and its temperature with the object to be heated (material, colour, form and surface) is absolutely crucial in infrared heating. For example, it may be that an object that perfectly absorbs a certain wave length of a certain emitter stays surprisingly cool when the same emitter is operated at a higher electric power and thus higher temperature. A change of power and temperature will always mean a shift in emitted wave lengths which, in turn, may pass through the object or be reflected.

Selection Aids

The following work guidelines give you valuable information for the correct selection of infrared heaters. While the selection according to application is solely based on practical experience, the selection according to temperature and wave length and selection according to spectra also specify the emitter-specific design parameters. The user manual include important safety and operation information.

IR Emitter Selection According to Application

IR Emitter Selection According to Temperature and Wave Length

Download the table Selection According to Temperature and Wave Length here.

IR Emitter Selection According to Spectra

In close co-operation with the faculty of experimental physics of the German University Duisburg-Essen we are constantly improving our infrared emitters. The testing and comparing of new substances and material are ever present research issues for us. The fruits of this research are products which possess high emission rates and therefore can be operated with low working temperatures at short heating and cooling periods. Furthermore, our infrared emitters show an energy coefficient of > 95%¹ auf.

Especially useful is the spectral measuring technology used by our scientific partner which makes the invisible infrared radiation "visible". Thus we exactly know from each of our emitters which wave length it radiates and at what intensity. If on the one hand it is pre-known how intensively the material to be heated absorbs the radiated wave lengths then the emitters can be chosen accurately – secure in the knowledge that the heating effect will be deployed completely; at the surface or with the target material.

Absorption transmission characteristics for most popular technical materials can be found in relevant spectral libraries and compendia. As alternative we can also exactly determine the characteristic of the material to be processed. If you are not satisfied with your process results, we recommend the spectral fine-tuning of emitter and processed material as safe method to reach the target. If you send us samples we can then test which emitters will achieve the required results in the best way.

The following charts show examples of comparable emission characteristics of our standard emitter types at varied electric power.

Spectra of other emitter types and wattages on request!

¹For ceramic, quartz emitters, quartz-halogen and quartz-tungston emitters together with a reflector.

Heating up and cooling down times by type

Choose an infrared emitter in order to see the heating up and cooling down times
or download the pdf with all curves here.

FFEH - Hollow Ceramic Emitters

FQE and PFQE - Quartz Cassettes

FTE - Solid Ceramic Emitters

HFEH - Hollow Ceramic Emitters

HQE and PHQE - Quartz Cassettes

HTE - Solid Ceramic Emitters

QFEH - Hollow Ceramic Emitters

QQE - Quartz Cassettes

SFEH - Hollow Ceramic Emitters

SQE - Quartz Cassettes

Operating Instructions

Due to the different design and characteristics of ceramic infrared heaters, quartz infrared heaters and quartz halogen heaters, there are specific user (operating) instructions for each of these three types of IR heaters available:

• Operating Instructions for Ceramic Heaters
• Operating Instructions for Quartz Cassette Heaters
• Operating Instructions for Quartz Halogen/Tungsten Emitters

The user instructions must be read in their entirety and observed in order to avoid design errors, damage during assembly or critical operating parameters.

Operating Instructions for Ceramic Heaters

Introduction

With infrared radiation from our infrared emitters, a wide variety of materials can be heated without contact. The energy transfer from the emitter to the product takes place almost immediately after switching on. This is because heat radiation, as electromagnetic radiation, is as fast as light and does not depend on "slow" transport media. Infrared emitters can therefore be used both in a vacuum and in an ambient atmosphere. The different designs and infrared wavelengths allow them to be used in a wide variety of applications.

Long wave ceramic heaters are robust, standardised and reasonably priced. At surface temperatures of 300°C to 750°C ceramic heaters emit medium-wave to long-wave infrared radiation between 2 and 10 µm. Most plastics and many other materials absorb this wavelength very well. Basically, there are two types: solid ceramic elements and hollow ceramic elements. The latter are hollow behind the heating wires, which ensures shorter heat up and cool down times as well as reduced heat losses to the rear. Both are available in standard dimensions, with and without thermocouple type K. Additionally, matching accessories such as reflectors are available whereby front emitted radiation in excess of 95% can be achieved.

Safety

As a manufacturer of heating elements, Freek is not responsible for the conditions in which its heating elements are installed, connected and used in the various customer-specific applications, nor is Freek responsible for how the heating elements are controlled. Rather, it is the customer's responsibility to be aware of and observe good engineering practice as it is recognised in the application and business markets in question. For example, many machines and their equipment are subject to the standard EN 60204 "Safety of machinery – Electrical equipment of machines".

Additionally, the customer is responsible for ensuring that electrical heating elements are only ever connected under the responsibility of a qualified electrician. This is because only a qualified electrician will know the risks associated with electrical heating elements, such as fire, explosion, combustion or electric shock, and – even more importantly – will know the safety measures that need to be put in place in order to prevent such events from occurring, even if the heating elements malfunction. Examples of these safety measures include protection against contact, thermal insulation, electrical insulation, temperature control, overtemperature prevention, earthing, residual current operated circuit breakers, overcurrent circuit breakers and miniature circuit breakers.

General Remarks & Handling

Risk of Overheating

• The aluminised projector/reflector or housing sheet metal used for our emitters begins to corrode at temperatures above 500°C. This causes the sheet metal to lose its reflective properties, which can result in critical overheating and thus destruction of the emitters.
• Under normal circumstances 500°C is rarely reached, even in high-power applications, due to the excellent reflective properties of the sheet metal (reflection factor ∼0.96). However, contamination, condensation, dripping water and "face-to-face" operation of radiators, reflectors, projectors, infrared platens can reduce the reflective effect and thus increase the risk of overheating.
• If these risks cannot be ruled out, we recommend using reflector plates and housings made of polished stainless steel (on request!), providing air cooling or using external temperature sensors to prevent overheating by temperature controllers.
• It must be avoided under all circumstances that the surface temperature of ceramic heaters exceeds 750°C.

Overcurrent

• Our infrared heaters are designed for operation at specified voltages. Any higher operating voltages differing from this can considerably reduce the lifetime or lead to immediate failure (15 % more voltage = 32 % more power!!!).

Safety Distance

• Please ensure that you always leave sufficient space between the beaded leads of our ceramic infrared heaters and the mounting or cover plates above/below them. In certain contaminated atmospheres, conductive deposits can form on surfaces which increase the risk of earth faults or short circuits.
• We recommend using a glass fibre sleeve over the beaded leads as additional touch protection measure.
• Ensure that infrared heaters cannot be touched during operation and that a safe distance to the heater is maintained so that no fires or burns can be caused by the radiation.
• The temperature of the infrared heaters can reach much higher than 600°C at the ceramic surface. As with all hot heat sources, it must be ensured that the atmosphere in which the heaters are operated does not contain explosive gases that could be ignited on contact with the heater surface. In all cases, the operator is responsible for ensuring that the heaters are suitable for the application.
• Due to thermal expansion, a minimum distance of 5 mm must be maintained between two heaters.
• The recommended distance between the radiant surface and the material to be heated is 100 to 200 mm.

Ventilation

• Substances that evaporate due to heat radiation can reduce the radiation power and lead to problematic deposits on leads and reflectors. Depending on the application, sufficient ventilation of the working area therefore must be provided.

Tests

• In every application, there are, in practice, working and environmental parameters which cannot be calculated exactly in theory. That is why we recommend generally testing ceramic heaters in the application under real working conditions in advance.

Wiring Diagram

Mounting of Ceramic Radiators / Installation in Reflectors

• Our ceramic terminal pillar is an integral part of the heater assembly. The heater back and the terminal pillar are one single ceramic component, which enhances the bonding strength of the heater. Compliance with the specified basic strength of the terminal pillar is monitored through AQL-sampling inspection. (see video:"strength testing of ceramic terminal pillar").
• The ceramic heaters are secured in place by inserting the fastening clip without using any tool to prevent damage to the guide groove of the ceramic terminal pillar (breakage, chipping).
• In cases where device-specific heater housing or custom heating platens with multiple closely spaced ceramic elements limit mounting freedom, manual insertion of the fastening clip may be challenging. In such situations, and/or when using reflector plates with a thickness over 1 mm, reducing the wave spring height may facilitate assembly. However, make sure that the ceramic heater fits securely (see video „adjusting wave spring height").
• When laying and connecting the beaded connection wires, do not pull on them as it may cause the wire connection inside the ceramic heater to break or shift. If this happens, the heater will no longer be safe to operate and must not be used.
• Damages resulting from improper installation are not covered by warranty. To facilitate easy proof that any damage or irregularities were present upon delivery, all our ceramic heaters are wrapped in protective film.

Operating Instructions for Quartz Cassette Heaters

Introduction

With infrared radiation from our infrared emitters, a wide variety of materials can be heated without contact. The energy transfer from the emitter to the product takes place almost immediately after switching on. This is because heat radiation, as electromagnetic radiation, is as fast as light and does not depend on "slow" transport media. Infrared emitters can therefore be used both in a vacuum and in an ambient atmosphere. The different designs and infrared wavelengths allow them to be used in a wide variety of applications.

In the case of medium-wave quartz emitters, a heating conductor heats quartz glass tubes and thus causes the glass to vibrate. Depending on the temperature, a dark red to bright orange glow can be seen.

Quartz infrared radiators have an emission spectrum comparable to ceramic radiators in the medium-wave and long-wave infrared spectrum. The difference is made by the short-wave spectral band below 3 µm, which only quartz infrared emitters have. Despite many overlaps, the application areas of both emitter types therefore differ. Due to their lower mass, quartz IR emitters have shorter response times and are thus recommended for cyclical or frequently interrupted work processes. However, quartz emitters are mechanically more fragile and for example not suitable for dusty atmospheres. Quartz infrared emitters are available as individual tubes or as cassettes. The dimensions of the cassettes follow those of the ceramic elements, so that ceramic and quartz infrared heaters can also be used in mixed arrangements in IR heating platens. For uniform installation, quartz cassettes are therefore also available with a ceramic connection socket, just like the ceramic elements.

Safety

As a manufacturer of heating elements, Freek is not responsible for the conditions in which its heating elements are installed, connected and used in the various customer-specific applications, nor is Freek responsible for how the heating elements are controlled. Rather, it is the customer's responsibility to be aware of and observe good engineering practice as it is recognised in the application and business markets in question. For example, many machines and their equipment are subject to the standard EN 60204 "Safety of machinery – Electrical equipment of machines".

Additionally, the customer is responsible for ensuring that electrical heating elements are only ever connected under the responsibility of a qualified electrician. This is because only a qualified electrician will know the risks associated with electrical heating elements, such as fire, explosion, combustion or electric shock, and – even more importantly – will know the safety measures that need to be put in place in order to prevent such events from occurring, even if the heating elements malfunction. Examples of these safety measures include protection against contact, thermal insulation, electrical insulation, temperature control, overtemperature prevention, earthing, residual current operated circuit breakers, overcurrent circuit breakers and miniature circuit breakers.

General Remarks & Handling

Risk of Overheating

• The aluminised projector/reflector or housing sheet metal used for our emitters begins to corrode at temperatures above 500°C. This causes the sheet metal to lose its reflective properties, which can result in critical overheating and thus destruction of the emitters.
• Under normal circumstances 500°C is rarely reached, even in high-power applications, due to the excellent reflective properties of the sheet metal (reflection factor ∼0.96). However, contamination, condensation, dripping water and "face-to-face" operation of radiators, reflectors, projectors, infrared platens can reduce the reflective effect and thus increase the risk of overheating.
• If these risks cannot be ruled out, we recommend using reflector plates and housings made of polished stainless steel (on request!), providing air cooling or using external temperature sensors to prevent overheating by temperature controllers.

Overcurrent

• Our infrared heaters are designed for operation at specified voltages. Any higher operating voltages differing from this can considerably reduce the lifetime or lead to immediate failure (15 % more voltage = 32 % more power!!!).

Installation Position

• Our quartz heaters should only be used in a horizontal mounting position. In moving applications/fields, it must be ensured that quartz heaters (tubes and cassettes) are always mounted crosswise to the direction of movement.

Safety Distances

• Please ensure that you always leave sufficient space between the beaded leads of our quartz infrared heaters and the mounting or cover plates above/below them. In certain contaminated atmospheres, conductive deposits can from on surfaces which increase the risk of earth faults or short circuits.
• We recommend using a glass fibre sleeve over the beaded leads as additional touch protection measure.
• Ensure that infrared heaters cannot be touched during operation and that a safe distance to the heater is maintained so that no fires or burns can be caused by the radiation.
• The temperature of the infrared heaters can reach much higher than 600°C at the glass surface. As with all hot heat sources, it must be ensured that the atmosphere in which the heaters are operated does not contain explosive gases that could be ignited on contact with the heater surface. In all cases, the operator is responsible for ensuring that the heaters are suitable for the application.
• Due to thermal expansion, a minimum distance of 5 mm must be maintained between two heaters.
• The recommended distance between the radiant surface and the material to be heated is 100 to 200 mm.

Ventilation

• Substances that evaporate due to heat radiation can reduce the radiation power and lead to problematic deposits on leads and reflectors. Depending on the application, sufficient ventilation of the working area therefore must be provided.

Tests

• In every application, there are, in practice, working and environmental parameters which cannot be calculated exactly in theory. That is why we recommend generally testing quartz heaters in the application under real working conditions in advance.

Wiring Diagram

Operating Instructions for Quartz Halogen/Tungsten Emitters

Introduction

With infrared radiation from our infrared emitters, a wide variety of materials can be heated without contact. The energy transfer from the emitter to the product takes place almost immediately when the unit is switched on. Heat radiation as electromagnetic radiation is as fast as light and does not depend on "slow" transport media. Infrared heaters can therefore be used both in a vacuum and in an ambient atmosphere. The various designs and infrared wavelengths allow them to be used in a wide variety of applications.

Short-wave quartz heaters are the infrared heaters with the highest radiation intensity (up to 20 W/cm²). They consist of a coiled tungsten wire in a hermetically sealed quartz glass filled with inert gas. Depending on the desired emission spectrum, differently coiled heating wires are used. R7s-connections are used as standard as they are also common for halogen spotlights as light sources. Alternatively, we offer various other fastenings and connections.

The heating and cooling times are only a few seconds, which makes them ideal for applications with short cycle times that have to start quickly or cool down quickly, for example when the conveyor belt is at a standstill.

Safety

As a manufacturer of heating elements, Freek is not responsible for the conditions in which their heating elements are installed, connected and used in the various customer-specific applications, nor is Freek responsible for how the heating elements are controlled. Rather, it is the customer's responsibility to be aware of and observe good engineering practice as it is recognised in the application and business markets in question. For example, many machines and their equipment are subject to the standard EN 60204 "Safety of machinery – Electrical equipment of machines".

Additionally, the customer is responsible for ensuring that electrical heating elements are only ever connected under the responsibility of a qualified electrician. This is because only a qualified electrician will know the risks associated with electrical heating elements, such as fire, explosion, combustion or electric shock, and – even more importantly – will know the safety measures that need to be put in place in order to prevent such events from occurring, even if the heating elements malfunction. Examples of these safety measures include protection against contact, thermal insulation, electrical insulation, temperature control, overtemperature prevention, earthing, residual current operated circuit breakers, overcurrent circuit breakers and miniature circuit breakers.

General Remarks & Handling

Freek's quartz-halogen/tungsten heaters emit primarily medium-wave and short-wave infrared radiation. The output is generated by a high-temperature tungsten coil housed in a sealed quartz tube.

Quartz halogen/tungsten heaters are a very powerful heat source, so some precautions must be taken during installation and operation.

• Gloves should be worn while handling the heater. Finger prints can affect the optical properties of the glass tube and may reduce the operating life of the heater.
• If necessary, clean any dirt, oil or lint from the heater with alcohol and a lint free cloth or tissue.
• Quartz halogen heaters can produce high intensity white light which could cause damage to human eyes. Care should be taken to ensure that personnel cannot look directly at the heaters during operation. If necessary, a filter to reduce the glare or protective glasses should be provided. In such cases, personnel should be warned of the danger using suitable signage.
• The heater is designed for horizontal operation only unless clearly specified for vertical operation.
• Quartz halogen/tungsten heaters may take up to 10 times the normal operating current when operated from cold (normal room temperature). Ensure that fuses or other protective devices are correctly specified to handle high starting currents.
• In cyclical processes, complete switch-off of the heaters should be avoided, as the high currents when frequently switched on again can have a negative effect on the service lifetime. If possible, the heaters should instead be kept on stand-by at low power.
• Ensure the heater is not exposed to vibration during operation as this will also reduce operating life.
• Excessive mechanical or physical force during handling or installation could break or damage the glass tube. Broken glass may be hazardous to personnel and also the heating process.
• Always turn the electrical power off before inserting, removing or cleaning the heater.
• Ensure heaters do not radiate directly onto nearby heaters as this will increase operating temperature and reduce operating life.
• The heater should be installed by a qualified person ensuring all relevant electrical safety standards are adhered to.
• The heaters should only be used in approved fixtures designed for quartz halogen/tungsten heaters.

Risk of Overheating

• The aluminised projector/reflector or housing sheet metal used for our emitters begins to corrode at temperatures above 500°C. This causes the sheet metal to lose its reflective properties, which can result in critical overheating and thus destruction of the emitters.
• Under normal circumstances 500°C is rarely reached, even in high-power applications, due to the excellent reflective properties of the sheet metal (reflection factor ∼0.96). However, contamination, condensation, dripping water and "face-to-face" operation of radiators, reflectors, projectors, infrared platens can reduce the reflective effect and thus increase the risk of overheating.
• If these risks cannot be ruled out, we recommend using reflector plates and housings made of polished stainless steel (on request!), providing air cooling or using external temperature sensors to prevent overheating by temperature controllers.
• The heaters must be protected by suitable measures (shielding, ventilation, sufficiently dimensioned "cold" connection length) against reaching temperatures above 300°C at the hermetically sealed flat connection ends. Otherwise the seal may be damaged, resulting in the immediate destruction of the radiators.
• When operating in a (partial) vacuum, the external convective air cooling is hardly present, if at all. The risk of critical overheating of the hermetically sealed flat connection ends is greater as a result. To minimise the risk of overheating, we therefore recommend not using standard radiators but instead dimensioning the cold connection ends longer. If standard emitters with "cold" standard connection length fail in applications in (partial) vacuum due to overheating of the connection ends, this is the sole responsibility of the customer.
• Ensure the temperature of the glass tube does not exceed 800°C.
• Ensure the heaters are operated at a safe distance from combustible materials.

Overcurrent

• Our infrared heaters are designed for operation at specified voltages. Any higher operating voltages differing from this can considerably reduce the lifetime or lead to immediate failure (15 % more voltage = 32 % more power!!!).

Installation Position

• The heater is designed for horizontal operation only unless clearly specified for vertical operation.
• In moving applications/fields, it must be ensured that quartz heater tubes are always mounted crosswise to the direction of movement.

Safety Distances

• Ensure that infrared heaters cannot be touched during operation and that a safe distance to the heater is maintained so that no fires or burns can be caused by the radiation.
• The temperature of the infrared heaters can reach much higher than 600°C at the glass surface. As with all hot heat sources, it must be ensured that the atmosphere in which the heaters are operated does not contain explosive gases that could be ignited on contact with the heater surface. In all cases, the operator is responsible for ensuring that the heaters are suitable for the application.
• Due to thermal expansion, a minimum distance of 5 mm must be maintained between two heater units (halogen heater in reflector).
• The recommended distance between the radiant surface and the material to be heated is 100 to 200 mm.

Ventilation

• Substances that evaporate due to heat radiation can reduce the radiation power and lead to problematic deposits on leads and reflectors. Depending on the application, sufficient ventilation of the working area therefore must be provided.

Tests

• In every application, there are, in practice, working and environmental parameters which cannot be calculated exactly in theory. That is why we recommend generally to test cartridge heaters in the application under real working conditions in advance.

Infrared Research

In order to shed light on the darkness of the "infrared half-truths", our cooperation partner Ceramicx Ireland developed the Herschel measuring robot in close cooperation with Trinity College Dublin and presented it as a world first at the K trade fair in Düsseldorf in 2013 (Ceramicx Center for Infrared Innovation (C²I²) ). Herschel can scan and visualize 3D images of a the heat flux that is radiated from any IR source. This unique ability is of inestimable value for the constructive and material design (material properties) and optimization of the infrared heating elements themselves (element design), as well as infrared ovens, IR heating platens and infrared heating devices of all kinds (solution design).