Watlow plug-in heater

Watlow plug-in heater

Product Family and Core Features

1. Product Line Overview

Core positioning of product series: Maximum operating temperature, maximum power density, key advantages

FIREROD ® Universal plug-in heater 1400 ° F (760 ° C) (Alloy 800 sheath) 400 W/in ² (62 W/cm ²) 60 years of industry validation, high thermal conductivity efficiency, supports multi scenario customization

High temperature FIREROD high-temperature working condition specific 1800 ° F (982 ° C) 100 W/in ² (15.5 W/cm ²) sealing design reduces oxidation, high emissivity sheath enhances heat transfer

Metric FIREROD global adaptation 1400 ° F (760 ° C) 330 W/in ² (50 W/cm ²) meets metric standards, has high dimensional accuracy, and is compatible with international equipment

MULTICELL ™ Multi zone precise temperature control 2050 ° F (1120 ° C) 30 W/in ² (4.6 W/cm ²) up to 6 independent temperature control zones, loose assembly design for easy disassembly and assembly

2. Core common advantages

Material and Structure: Made of nickel chromium resistance wire (uniform heating), magnesium oxide (MgO) insulation layer with specific grain purity (high dielectric strength, rapid heating), Alloy 800 or stainless steel sheath (anti-oxidation, corrosion-resistant).

Process design: Minimize the distance between the resistance wire and the sheath, reduce internal temperature, and support high power density operation; UL ®/ CSA certified leads, with insulation levels ranging from 250 ° C to 842 ° C.

Safety and reliability: non-volatile design, strong high-temperature stability; Some models support low leakage construction and are suitable for sensitive scenarios such as healthcare.

Detailed explanation of key technical specifications

1. Dimensions and tolerances

（1）FIREROD ®  standard size

Nominal diameter (in) Actual diameter (in/mm) Minimum sheath length (in/mm) Maximum sheath length (in/mm) Diameter tolerance

1/8 0.122（3.1） 7/8（22.2） 12（305） ±0.002 in（±0.05 mm）

1/4 0.246（6.3） 7/8（22.2） 36（915） ±0.002 in（±0.05 mm）

1/2 0.496（12.6） 7/8（22.2） 60（1520） ±0.002 in（±0.05 mm）

1 0.996（25.3） 1 1/4（32.0） 72（1830） ±0.003 in（±0.08 mm）

(2) Tolerance requirements

Length tolerance: The sheath with a length tolerance of ≤ 4.5 in (114 mm) is ± 3/32 in (± 2.4 mm); The sheath with a diameter greater than 4.5 inches is ± 2% (1/8 inch diameter is ± 3%).

Power tolerance: 1/8 inch diameter is+10%/-15%, other diameters are+5%/-10%.

Resistance tolerance: 1/8 inch diameter is+15%/-10%, other diameters are+10%/-5%; Resistance varies with temperature, with room temperature (before use) being 90% of the value calculated by Ohm's Law, and after use being 95%.

2. Electrical performance

（1）FIREROD ®  Voltage and power range

Diameter (in) Maximum voltage (V) Maximum current (A) 120V Minimum power (W) 240V Maximum power (W)

1/8 240 3.1 - 720

1/4 240 4.4 100 1050

3/4 480 23.0 30 5520

1 480 23.0 - 5520

(2) Metric FIREROD Electrical Parameters (Example)

Diameter (mm) Maximum voltage (V) 230V Maximum power (W) 400V Maximum power (W) Maximum current (A)

6.5 250 1650 - 7.2

16 480 4830 8400 21

20 480 4830 8400 21

3. Power density and application adaptation

Power density directly affects heating efficiency and heater lifespan, and should be selected based on the heating medium and operating conditions

Metal heating: The maximum allowable power density varies with the aperture fit gap and temperature (for example, at 1400 ° F, a fit gap of 0.005 in corresponds to a power density of approximately 80 W/in ²).

Air/gas heating: At an ambient temperature of 70 ° F, the maximum allowable power density for a single heater is approximately 60 W/in ²; When multiple devices are parallel, they need to be multiplied by a correction factor of 0.95, and when equipped with a reflector, they need to be multiplied by 0.85.

Mobile air heating: The higher the wind speed, the greater the allowed power density (for example, at a wind speed of 100 FPM, the power density can reach 1000 W/in ²).

Installation and Wiring Guide

1. Installation preparation

Aperture matching: It is recommended that the aperture be 0.001-0.006 inches larger than the actual diameter of the heater (for metal heating). A gap that is too large can reduce thermal efficiency, while a gap that is too small may make disassembly difficult.

Installation location: The sensor should be installed in a temperature uniform area, away from the edge of the heat source; The sheath should be in full contact with the heating medium to avoid local overheating.

Environmental requirements: Avoid installing in close proximity to noise sources such as motors and relays; In humid environments, models with sealing (PTFE/silicone) should be selected.

2. Wiring specifications

(1) Lead type and specifications

Lead type, maximum temperature, applicable scenarios, wire diameter specifications (example)

GGS fiberglass 482 ° F (250 ° C) universal scenario 18 AWG (1/2 inch diameter heater)

MGT 842 ° F (450 ° C) high temperature scenario 18 AWG (3/4 inch diameter heater)

PTFE 392 ° F (200 ° C) corrosion-resistant scenario 20 AWG (3/8 in diameter heater)

Mineral Insulation (MI) 1500 ° F (815 ° C) Extreme High Temperature/Vibration Scenarios Conductor Diameter 0.044 in (3/8 in diameter heater)