Watlow Immersion Heater

Watlow Immersion Heater

Core Product System and Classification

（1） Spiral plug immersion heater (WATROD) ™  and FIREBAR ®  Screw Plug）

1. Product positioning and applicable scenarios

Specially designed for direct immersion heating of liquids, it can be used for heating various oils, heat transfer solutions, and other liquids. Typical applications include industrial rinse tanks, steam degreasing equipment, hydraulic oil heating, antifreeze (ethylene glycol) solution heating, and other scenarios. For example, in clean water heating scenarios, a 1-inch NPT screw plug paired with WATROD components can meet the heating needs of different water qualities such as deionized water and drinking water.

2. Structure and Component Characteristics

Heating element: It includes WATROD circular tubular element and FIREBAR flat tubular element, both of which adopt a hairpin bending design. According to the compatibility between the element sheath and the plug material, they are fixed on the spiral plug by welding or brazing. Among them, WATROD hair clips undergo recompacted treatment to maintain magnesium oxide (MgO) density, dielectric strength, heat transfer efficiency, and service life.

Terminal box: The standard configuration is a universal terminal box, and optional types such as moisture-proof, explosion-proof, and moisture-proof explosion-proof composite are provided to adapt to different environmental requirements. For example, in humid or explosive gas environments, corresponding protective terminal boxes can be selected, and the terminal boxes can be rotated for easy connection with existing conduits.

Auxiliary components: Some models are equipped with integral thermocouple sleeves, which facilitate the insertion and replacement of temperature sensors without the need to drain the heated fluid; Optional thermostats can achieve convenient process temperature regulation, such as SPST (single pole single throw) and DPST (double pole single throw) types, with a temperature control range covering 30-550 ° F.

3. Key performance parameters

Power and Voltage: The power density can reach up to 120 W/in ² (18.6 W/cm ²), with a power range from 250 watts to 38 kilowatts, voltage adaptation to 120-480VAC, and UL certification ®  CSA component certification supports up to 480VAC and 600VAC respectively.

Sheath material and temperature: Different sheath materials correspond to different maximum operating temperatures. Alloy 800/840 sheath has a maximum temperature of 1600 ° F (870 ° C), 304/316 stainless steel sheath has a maximum temperature of 1200 ° F (650 ° C), and steel sheath has a maximum temperature of 750 ° F (400 ° C), which can be selected according to the temperature requirements of the heating medium.

Size specifications: Spiral plug sizes include NPT specifications such as 3/4 inch, 1 inch, 1.25 inch, 2 inch, 2.5 inch, and some also support European G-type (brass material) and BSP type (stainless steel material) thread standards. Taking a 1-inch NPT plug as an example, it can be paired with 0.260-inch and 0.315-inch WATROD components; The 2.5-inch NPT plug can be compatible with 0.430-inch, 0.475-inch WATROD components and 1-inch FIREBAR components.

4. Customization and accessory options

Material customization: In addition to standard sheath and plug materials, special sheath materials such as Hastelloy C276 and titanium alloy, as well as plug materials such as 304H, 316H, and 321 stainless steel, can also be provided to meet the needs of highly corrosive or special working conditions.

Functional accessories: optional indicator lights (PL10 and PL11 models), PL10 is compatible with up to 250VAC and equipped with 6-inch (152mm) leads; PL11 is compatible with 480VAC and equipped with 4-inch (102mm) leads, which can visually display the power on/off status of the heater. In addition, an adapter for spiral plugs to flanges is also provided, which facilitates the replacement of spiral plug heaters with flange heaters. The adapter material is mostly steel, and different specifications correspond to different shipping weights. For example, the shipping weight of the 1.25 inch to 3-inch to 150 # adapter is 13 pounds (5.9kg).

（2） ANSI Flange Immersion Heater (WATROD and FIREBAR ANSI Flange)

1. Product features and applicable scenarios

Suitable for scenarios that require high-power heating and high installation stability, such as liquid heating in large storage tanks and industrial reactors. It can handle various media such as clean water, process water, heavy oil, asphalt, etc. Its flange structure ensures sealing performance under high pressure conditions, with pressure ratings ranging from 150 pounds, 300 pounds, 600 pounds, etc.

2. Core parameters and structure

Power and density: The power density can reach up to 100 W/in ² (15.5 W/cm ²), providing higher heating power to meet the rapid heating needs of large capacity media.

Flanges and components: Flange sizes range from 2 inches to 48 inches, suitable for different equipment interfaces; The heating element also includes WATROD and FIREBAR types, and the connection method between the element and the flange is determined based on material compatibility to ensure pressure sealing effect.