Product Overview
A flexible heater applied to freeze protection holds a tank, pipe, valve, pump, or instrument above the freezing point (or any minimum maintain temperature) in cold ambient conditions. Because the thin, conformable heater wraps or adheres directly to the item, the heat goes into the metal rather than the surrounding air, and a thermostat or controller cycles it to hold the set point efficiently. Shaped to the part, it covers irregular surfaces — valve bodies, pump housings, instrument enclosures, and small tanks — that a straight heat-trace cable cannot follow well. The same construction does double duty for condensation and moisture prevention, keeping enclosures and components dry. Built to your drawing and/or specification, in the substrate the environment calls for.
Related Hi-Heat flexible-heater options
Silicone Rubber Heaters — rugged, moisture-tolerant substrate — the freeze-protection workhorse, to ~200°C
Polyimide (Kapton) Heaters — thinnest format for vacuum, cleanroom, and tight-clearance work
Medical & Laboratory Instrument Heaters — conformable heat for instruments and analyzers
Wire-Wound Element Heaters — highest watt density, economical for many shapes
Key Features & Benefits
- Heat goes into the part, not the air — the heater wraps or adheres directly to the surface, so it conducts heat into the metal instead of warming the surrounding space — faster response and far less wasted energy than heating the ambient. The efficient way to hold a specific item at temperature.
- Conforms to the shape the application actually has — a thin flexible substrate follows valve bodies, pump housings, instrument enclosures, and curved tanks that a rigid heater or a straight cable cannot cover well. Shaped to the part, not the part to the heater.
- Built to your drawing, in the substrate the environment needs — silicone for rugged moisture and washdown duty, polyimide for vacuum/cleanroom and tight-clearance electronics, polyester for cost-sensitive low-temperature work — every heater laid out to the surface, temperature, and environment you give us. One platform, the right material for the job.
- Control and safety designed in — a bonded-in sensor, a thermostat or PID/SCR loop, and an independent high-limit make a complete controlled assembly — or a snap-action thermostat laminates right into the heater for a compact integral package. Holds the set point and protects the part.
- UL Recognized and ISO 9001:2015 behind it — the heater is a UL Recognized Component (with customer-specific UL file numbers available) made under a third-party-audited ISO 9001:2015 quality system — the documentation an OEM and its inspector expect. Drops into a UL-Listed end product as a recognized component.
Specifications
- Operating principle
- Electric resistance (Joule) heating — current passes through a resistance element laminated into a thin, conformable substrate, so the heater can wrap or adhere directly to a surface that is not flat and put its heat into the part rather than into the surrounding air.
- Substrate (construction)
- Three substrates, chosen by temperature, ruggedness, and thickness: silicone rubber (rugged, moisture-tolerant, the general-purpose choice), polyimide / Kapton (the thinnest format, with aerospace-grade thermal stability and low outgassing for vacuum and cleanroom service), and polyester film (a cost-effective option for low-temperature OEM work).
- Element type
- Wire-wound — a resistance wire laid in a pattern, reaching the highest watt densities and economical for many shapes; or etched-foil — a thin metal foil photo-etched into a precise circuit that spreads heat very uniformly, holds a tight resistance tolerance, and can be routed around cut-outs and sensors. Etched-foil delivers a lower, more even watt density; wire-wound gives maximum watt density or lowest cost.
- Shape, area & thickness
- Built to the surface it heats — the heated area and shape are laid out to your drawing or sketch, with cut-outs, holes, and lead-exit locations placed where the part requires. The flexible substrate conforms to irregular surfaces (valve bodies, pump housings, instrument enclosures, curved tanks) that a rigid or cable-style heater cannot follow.
- Attachment to the part
- Three common methods: factory-applied pressure-sensitive adhesive (PSA) backing for a clean smooth surface (the quickest install); factory vulcanizing or bonding to a plate or component for the best thermal contact and durability; or mechanical clamping / strapping for pipes, drums, and removable installations. Intimate, gap-free contact is the goal — an air gap is thermal resistance that makes the heater run hotter than it should.
- Sensors & lead exits
- A temperature sensor (thermistor, RTD, or thermocouple) can be bonded into or next to the heater, and a snap-action thermostat can be laminated right into the assembly for a compact integral control. Lead-wire type, length, and exit location are specified per job.
- Temperature range
- By substrate (verbatim): polyester film serves to about 105°C (221°F); silicone rubber is UL rated with a maximum continuous operating temperature of 200°C (392°F) and remains flexible at −57°C (−70°F); polyimide / Kapton serves to about 260°C (500°F) with aerospace-grade thermal stability and low outgassing for vacuum and cleanroom use. Every construction has a maximum temperature and watt density — running within them is what gives a flexible heater a long service life.
- Watt density
- Watt density (watts per square inch) is the value to get right — too high scorches the substrate or the part, too low cannot reach temperature. It is set by the substrate, the element type (etched-foil spreads a lower, more even density; wire-wound reaches higher densities), and what the part can take without a hot spot, and is sized per job rather than published as a fixed catalog value.
- Voltage
- Wound to the application voltage, single-phase — specify the available service voltage with the request.
- Control & safety
- A flexible heater needs a control loop and an independent safety. Typical packages pair a bonded-in temperature sensor with a thermostat (on/off duty) or a PID controller driving an SCR or solid-state relay (tight control), plus an independent high-limit cut-out so a control fault cannot overheat the part. For compact installs a snap-action thermostat laminates into the heater.
- Certifications
- UL Recognized Component — customer-specific UL file numbers available; the silicone-rubber line is UL-rated for continuous operation to 200°C (392°F). Manufacture is ISO 9001:2015 certified (Perry Johnson Registrars, ANAB-accredited).
- Build & ordering
- Custom build-to-drawing-and/or-specification — substrate, element, watt density, shape, cut-outs, lead exits, sensors, and attachment are specified per job, so virtually every heater is engineered to its part. No published price list, quote-only. Hi-Heat is an authorized-distribution line: Prater Technical Partners is the vendor of record, with the heater drop-shipped from the factory (optional Prater kitting).
Common Applications
- Freeze protection of valves, pump housings, and instrument enclosures — heat shaped to the irregular surface a cable cannot follow
- Freeze / minimum-maintain protection of small tanks, drums, and reservoirs in cold ambient
- Condensation and moisture prevention in outdoor enclosures and electronics — keeping components dry
- Viscosity control — holding oils, lubricants, and process fluids warm enough to flow
- Telecom cabinet and outdoor-equipment heating
- Battery and energy-storage heating for cold-weather performance
Fit limit: a flexible heater is sized to maintain a surface at a set point, not to thaw a fully frozen mass quickly or to heat a flowing process stream. For freeze protection on long pipe runs a heat-trace cable may be the better tool; for heating a flowing fluid to a controlled outlet temperature, an inline circulation heater is the answer. Use the input form to tell us the item, the minimum ambient, and the maintain temperature and we will confirm the right approach.
Design & Selection Considerations
- Size to the heat loss, not just the area — a freeze-protection heater fights the heat the part loses to a cold ambient, so the watt density follows the minimum ambient, the wind/exposure, and any insulation — not the surface area alone. Use the input form to give us the coldest expected ambient and whether the item is insulated. An under-sized heater holds in mild cold and loses the part on the worst night.
- Cover the cold spots, not just the easy faces — a valve bonnet, a pump volute, or a flange loses heat fastest at its thinnest, most exposed features — that is where ice forms first. A heater shaped to wrap those features beats a flat pad on one face. Heat where it leaves, not where it is convenient to mount.
- Insulate over the heater — an exterior freeze-protection heater is only as good as the insulation over it; a bare heater on a cold surface fights the ambient continuously and may not hold. Plan the lagging or insulation jacket as part of the install. The insulation does half the work — design it in.
- Use an integral snap-action thermostat for compact, unattended installs — a snap-action thermostat laminated into the heater gives a self-contained freeze-protection assembly with no external control to wire — ideal for a valve or instrument far from a panel. For a forgiving maintain band, the integral control is the simplest reliable choice.
- Choose silicone for outdoor and washdown exposure — freeze-protection duty usually means moisture, weather, and rough handling, which point to the silicone-rubber substrate for its ruggedness and moisture tolerance; reserve polyimide for tight-clearance or vacuum work. Match the substrate to the weather, not just the temperature.
- Keep an independent high-limit even on a low-temperature job — a freeze-protection set point is low, but a stuck thermostat or a lost-contact air gap can still drive the surface hot; an independent high-limit protects the part and the substrate. A safety is cheap insurance against a single-point control failure.
To spec the right Hi-Heat freeze-protection heater:
Use the input form to send a drawing or sketch of the surface, the target maintain temperature, the minimum ambient (for freeze / condensation duty), the voltage available, the environment (washdown, vacuum, cleanroom, abrasion), and the quantity — and we’ll spec the substrate, element, watt density, attachment, and control to suit, then quote it.
Electric Heating Application Sheet ›Talk to an engineer directly — Scott Prater, Principal · 917-580-0878 · scott@pratertechnical.com
Specifications compiled by Prater Technical Partners from Hi-Heat Industries published product specifications.