| 摘要 |
An internal pipe coating apparatus for coating the interior surface of uncoated weld joints in an otherwise internally coated pipeline comprising a frame having wheels at the forward and rear ends thereof, the forward end being oriented or directed towards the uncoated weld joint to be coated, and a drive motor for driving one pair of wheels to move the coating apparatus towards and beyond the uncoated weld joint. A feeler mechanism is located at the rear end of the apparatus. Means are provided to elevate the feeler mechanism into contacting position against the internal surface of the pipe when the drive motor is actuated to move the apparatus in a forward direction. The feeler mechanism comprises a pair of electrically conductive arms adapted to bear against the internal surface of the pipe and to create a completed circuit through the pipe when the feeler arms engage the bare surface of the uncoated weld joint to stop the drive motor. A rotating hollow shaft is also located at the rear end of the coating apparatus. This hollow rotating shaft is provided with a hollow hub and a plurality of hollow radiating arms adapted to spray powder on the uncoated weld joint, which has been previously heated in a conventional manner. A spin motor is provided to rotate the shaft and hub. The spin motor is actuated when the coating cycle is initiated. A powder suspension device is also located on the coating apparatus and a fan or blower is actuated in response to the actuation of the spin motor to provide air under pressure to the powder suspension device to suspend powder therein. A valve is located on the outlet of the powder suspension device and a motor is provided to spin the hollow shaft and the hub. After the spinning motor has been actuated and after the fan has been actuated to suspend powder in the powder suspension device, the valve from the powder suspension device is then opened to provide a stream of powder to the hollow shaft so that a suspension of powder passes out of the hollow arms by centrifugal force to coat the heated weld joint. After a predetermined period of time, the valve from the powder suspension device is closed, the fan motor is turned off, and finally the spin motor is shut off.
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