| 摘要 |
A water heater construction (10) including an inner tank (12) for containing water surrounded in spaced apart relationship by an outer shell (14). An outer collar (22) of insulation material is located in the annular space (16) between the inner tank (12) and outer shell (14) at a preselected location within the annular space (16) along the height of the water heater construction (10). The collar (22) has a radial thickness greater than the radial width of the annular space (16) and is radially compressed between the interior wall of the outer shell (14) and exterior wall of the inner tank (12). An expandable foam thermal insulation material (30) fills the annular space (16) above the collar (22). A method of making the water heater construction (10) includes the steps of positioning the collar (22) of insulation material around and in contact with the interior wall surface of the outer shell (14) and moving the outer shell (14) downwardly concentrically over the inner tank (12) displacing the inner perimeter margin of the collar (22) at the interface of the collar (22) and the water tank (12) in a generally upward direction to form a trough in the collar (22) at the top side of the collar (22).
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