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Thick Film Heaters · Fluid & Instant Water Heating

Medical Fluid Warming Thick Film Plates

Continuous to 150 °C, wound for 24-220 V, built to UL 499 / IEC 60335 / RoHS. Set the outline, the voltage and the wattage on the drawing below and it redraws to them.

Medical Fluid Warming Thick Film Plates are continuous to 150 °C, wound for 24-220 V, watt density 5 W/cm² in free air and 30 W/cm² bonded to a heat sink, about 1.5 mm to 3 mm thick. The outline is cut to your drawing, up to 120 x 200 mm in one piece. It does not limit its own temperature: a thermostat, a thermal cutoff or a control loop with an independent over-temperature channel belongs in the design.

Continuous temperature
to 150 °C
Supply voltage
24-220 V
Watt density
5 W/cm² free air / 30 W/cm² bonded
Thickness
1.5 mm to 3 mm
Maximum one-piece size
120 x 200 mm

These are the process limits for this construction, not the rating of a finished part. The ratings of your heater come from the drawing it is built to, and the watt density it can carry depends on what it is bonded to.

Outline & Specification Builder

Set the outline, the size, the voltage and the power you have in mind. The drawing redraws to match, and the panel works out the heated area, the watt density and the current — then checks that watt density against what this construction survives in free air and bonded to a heat sink. Those two limits are different by several times, and it is the difference that decides whether a heater lasts.

Fills in the form below; attach your outline drawing or DXF there.

Request a Quotation for Medical Fluid Warming Thick Film Plates

The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

Request a Quotation

The part

If you have an outline drawing or a DXF, say so in the notes and we will reply with an address to send it to — a drawing turns an estimate into a quotation.

Business Information

Dimensions & Specifications (UL 499 / IEC 60335 / RoHS)

Every row below is a starting point for the customizer above — pick any size and the drawing will redraw to that row.

ParameterSpecificationLimit / note
ConstructionGlass dielectric and resistor pastes screen printed and fired onto the substrate, then laser trimmed to resistanceFired, bonded or encapsulated as a single assembly
Substrate316L stainless or aluminaThe substrate carries the heat and the mechanical load
Thickness1.5 mm to 3 mmSubstrate plus element system
Maximum size, one piece120 x 200 mmLimited by the firing or curing fixture
Dimensional toleranceu00b10.2 mm on the substrate, u00b10.1 mm on printed featuresOn the machined substrate
Supply voltage12 V DC to 400 V ACCircuit is designed for the ordered voltage
Resistance toleranceu00b110% standard, u00b15% selectedThick film resistors are laser trimmed where a tighter band is required
Watt density5 W/cmu00b2 typical, 30 W/cmu00b2 maximum in a wetted applicationAchievable because the heat is generated in the surface being cooled
Maximum working temperature+150 u00b0C at the element systemOf the element system; the substrate itself tolerates more
Dielectric strength2500 V AC, 1 minuteOne minute, circuit to substrate
Insulation resistancegreater than 100 Mu03a9 at 500 V DCAt 500 V DC
TerminationsWelded tabs, crimp terminals or soldered leads depending on temperatureSoldered, welded or crimped as the temperature allows
MountingBolted, brazed or welded into the assembly; flatness of the mating face is criticalFlatness of the mating face matters more than clamping force
Sensor and control optionsPrinted PTC or NTC track, or a bonded thermocoupleIntegrated into the same firing or bonded to the substrate
Certifications availableUL 499, IEC/EN 60335, RoHS, REACH, CEConstruction level
Control accuracyu00b10.5 u00b0C at the plate with a two-sensor loopOne sensor controls, the second is an independent over-temperature channel
RedundancyIndependent hardware cutoff separate from the software loopRequired by IEC 60601 for anything warming fluid that reaches a patient

Medical Fluid Warming Thick Film Plates are thick film heaters. There is no catalogue size and no stocked part number here — the drawing decides the outline and the wattage. What this page gives you instead is everything that constrains the drawing: watt density, temperature, thickness, tolerance, voltage and the certifications the construction is built to.

What Are Medical Fluid Warming Thick Film Plates?

Medical Fluid Warming Thick Film Plates are thick film heaters. They are specified by supply voltage and outline together with the outline drawing, the wattage or the temperature to be held, and what the heater is bonded to — that last one decides the permissible watt density and is the question a quotation cannot skip. The construction is built and tested to UL 499 / IEC 60335 / RoHS.

Construction & Insulation System

There is no separate element. A glass dielectric and a resistor paste are screen printed onto the substrate — 304 or 316 stainless, 96% alumina, or anodised aluminium — and fired at around 850 °C, then laser trimmed to resistance. The heated surface IS the substrate, so there is no adhesive, no air gap and no interface in the heat path, which is why watt densities an order of magnitude above any flexible construction are achievable. It is also why every fluid application needs dry-run protection: with no water over it, a plate at 100 W/cm² has seconds of margin, not minutes.

Watt Density

In free air, with nothing conducting heat away from it, this construction carries 5 W/cm². Bonded over its full area to metal that carries the heat off, it carries 30 W/cm². The second figure is not an upgrade of the first — it is a different operating condition, and a heater ordered at 30 W/cm² and then run unbonded fails within minutes. Divide the wattage you need by the area you have before anything else: if the answer is above the free-air figure, either the area grows or the heater gets bonded down.

Typical Applications

Instant water heating in coffee machines, dispensers and sanitary ware; medical fluid and blood warming; dialysis and analyser fluid lines; laboratory hotplates and steam generation — applications where the fluid has to be heated fast, with no tank, no warm-up and no immersion element in the flow.

Inside the plant

Manufactured in our own plant

This heater is laid out, wound or etched, laminated, cut, tested and imaged in-house. The stages below are where its resistance tolerance, its temperature uniformity and its insulation integrity are actually decided.

  1. Engineer laying out a heater circuit over a customer outline
    01

    Circuit design & layout

    The customer outline comes in as a drawing or a DXF, and the element is laid out inside it: conductor gauge from the voltage, path length from the resistance, pitch from the watt density wanted at each part of the surface. Where the load needs more heat at the edges than in the middle, that is decided here, in the geometry, not later with more power.

    Calculated resistance and watt density checked against the construction limits before any tooling is cut.

  2. Etched foil circuits and wound nichrome elements ready for lamination
    02

    Element preparation

    Wire-wound elements are wound on a glass carrier at the calculated pitch; etched-foil circuits are photo-imaged and etched from Inconel or copper foil to a trace width held within 0.05 mm. That tolerance is what makes the resistance repeatable from lot to lot, which is what makes the temperature repeatable.

    Trace width and element resistance measured before lamination — a circuit out of tolerance is scrapped here, not after it is sealed inside the part.

  3. Heated press closing on a silicone heater lay-up
    03

    Lamination & vulcanising

    The element and its sensor are laid between the insulation and pressed under heat: silicone is vulcanised, polyimide and PET are laminated with a high temperature adhesive, epoxy plates are potted under vacuum so no voids are left anywhere in the heat path. A void is not a cosmetic defect — it is a place the heat cannot leave from, and it becomes the hot spot that ends the part.

    Press temperature, pressure and dwell recorded per lot; potted plates checked for voids.

  4. Die cut heater blanks with leads and connectors fitted
    04

    Die cutting & leads

    The outline is die cut with radiused corners — a die does not cut an inside corner, and a sharp corner in a film is where a tear starts. Leads are crimped or soldered and strain relieved at the exit, and connectors are fitted to the harness drawing so the assembly line never has to solder.

    Outline to ±0.5 mm on film, ±1.5 mm on silicone; lead pull-out tested per lot.

Video: Medical Fluid Warming Thick Film Plates

Introduction to Fluid Warming Products

Third-party video, selected automatically for this topic. It is not produced by Heating Film and is not a specification source — use the tables on this page for dimensional data.

Frequently Asked Questions

Is there a standard size range for Medical Fluid Warming Thick Film Plates?

There is no size list. Medical Fluid Warming Thick Film Plates are cut to your outline, so the size is whatever your drawing says, up to 120 x 200 mm. Larger areas are built as separate zones with their own circuits. Send a dimensioned drawing or a DXF and the quotation comes back against that outline.

What watt density can Medical Fluid Warming Thick Film Plates run at?

Two figures, and they are not interchangeable. In free air, with nothing conducting heat away, 5 W/cm². Bonded over its full area to metal that carries the heat off, 30 W/cm². A heater ordered at the second figure and then run in the first condition fails within minutes, so the quotation asks what the heater is bonded to before it asks anything else.

How hot can Medical Fluid Warming Thick Film Plates run?

150 °C continuously. That limit belongs to the insulation system — Stainless Steel Substrate (thick film) or Alumina Ceramic Substrate (96% Al2O3) — not to the element, which would tolerate a good deal more. It is a hard ceiling: above it the insulation degrades, and no derating scheme buys headroom. Past 150 °C the construction has to change rather than be pushed.

What protects Medical Fluid Warming Thick Film Plates from overheating?

Nothing in the heater itself — a heater is a resistor and has no opinion about temperature. The protection is a separate part of the design, and on this construction it is normally a bimetal thermostat or a one-shot thermal cutoff fitted inside the insulation, in series with the element. It can be built into the heater at manufacture, which is both cheaper and more reliable than adding it to the assembly afterwards, and it is a different component from the sensor that closes the control loop: the case the cutoff exists for is the loop failing on.

How are Medical Fluid Warming Thick Film Plates fitted?

They are clamped between machined faces with a thermally conductive interface, where flatness of the mating face matters more than clamping force.

What voltages are Medical Fluid Warming Thick Film Plates available in?

24 V DC, 48 V DC, 110-120 V AC and 220-240 V AC. The element is wound for the voltage ordered — it is not a switchable range, and running a heater at a voltage other than the one it was wound for changes its power by the square of the ratio. Resistance is held to u00b10.2 mm on the substrate, u00b10.1 mm on printed features.

What is the dielectric strength of Medical Fluid Warming Thick Film Plates?

2500 V AC, 1 minute, with insulation resistance above 100 MΩ at 500 V DC measured after the dielectric test. Both are tested on every unit rather than on a sample, because a heater that fails this test in service fails it into whatever it is bonded to.

How do I get a quotation?

Set the outline, size, voltage and power in the builder on this page and send that configuration through, or attach a drawing. The quotation needs six things: the outline, the supply voltage, the power or the temperature you need to hold, what the heater is bonded to, the ambient it works in, and the quantity. With those, a quotation comes back within one business day.