300156 - Miller 40-Inch Pipe PWHT Insulation Blanket (24x140)

Miller 300156 Insulation Blanket for 40-Inch Pipe PWHT

The Miller 300156 is a specialized insulation blanket engineered for use in induction heating applications, specifically targeting Post Weld Heat Treatment (PWHT) and preheating on 40-inch diameter pipes. This accessory is a critical component in the Miller ProHeat induction heating ecosystem, designed to maximize thermal efficiency and ensure the integrity of the heating process. The blanket measures 24 inches in width and 140 inches in length, providing the necessary circumference coverage for large-bore piping often found in transmission pipelines, petrochemical facilities, and power generation plants.

Constructed from high-temperature resistant materials, this sewn blanket serves a dual purpose. First, it acts as a thermal barrier between the heated workpiece and the induction coils (or the environment). By retaining heat within the pipe, it ensures that the energy delivered by the power source is utilized effectively, reducing power consumption and helping operators achieve the precise temperature ramp rates and soak times required by welding codes (such as ASME Section IX or API 1104). Second, it protects the liquid-cooled or air-cooled induction cables from the radiant heat of the pipe, preventing damage to the insulation of the cables themselves and extending the lifespan of the heating element.

The 300156 model is pre-cut and sized to eliminate the guesswork and labor associated with cutting bulk insulation rolls in the field. Its dimensions are optimized for 40-inch pipes, ensuring a snug fit without excessive waste or gaps that could lead to cold spots. The blanket is flexible and durable, capable of withstanding the rigors of on-site industrial environments. It is typically used in conjunction with other induction accessories such as preheat cables and temperature monitoring thermocouples to form a complete, code-compliant heat treatment solution.

Proper insulation is paramount in induction heating. Without adequate coverage, the system may struggle to reach target temperatures, or the temperature gradient across the heat-affected zone (HAZ) may become uneven. The Miller 300156 mitigates these risks by providing a consistent, high-quality insulation layer that supports uniform heating. This product is an essential stock item for contractors performing stress relieving on large diameter carbon steel or alloy pipes.