Thermoplastic melting kettle material circulation system

A melter kettle for melting thermoplastic pavement marking material in combination with molten thermoplastic circulation system, wherein the molten thermoplastic circulation system comprises:

• a vertical material transfer tube coupled to a side of the melter kettle and in fluid communication with and extending between the bottom and top of the melter kettle for transferring molten thermoplastic material between the bottom and top of the melter kettle;
• and
• a heat chamber surrounding at least a portion of the vertical material transfer tube through which a heated fluid flows
• wherein
• the melter kettle includes a first outlet port to which the vertical material transfer tube is coupled to provide the fluid communication with the bottom of the melter kettle;
• and
• the melter kettle includes a second outlet port through which molten thermoplastic material can be applied to a pavement, which second outlet port is separate from the first outlet port.

A method of melting a thermoplastic material in a melter kettle having a combustion chamber, said method comprising the steps of:

• a) charging thermoplastic material into the melter kettle;
• b) combusting a fuel source in the combustion chamber to heat and melt the thermoplastic material in the melter kettle;
• c) removing molten thermoplastic material from the bottom of the melter kettle and transferring the removed molten thermoplastic material into the top of the melter kettle
• wherein
• the melter kettle is provided with a first outlet port through which the molten thermoplastic is removed from the bottom of the melter kettle and transferred into the top of the melter kettle in step c);
• and
• the melter kettle is provided with a second outlet port through which molten thermoplastic material can be applied to a pavement, which second outlet port is separate from the first outlet port.