Patent ID: 6681839
Filing Date: 2004-01-27
Classification: F28G

Abstract:
A heat exchanger exchange-tube cleaning lance positioning system for use with an exchange-tube cleaning lance on a heat exchanger having an tube sheet accessible by removing an exchanger head connected to a heat exchanger head flange; the tube sheet having an open end of each of the exchange-tubes in the heat exchanger provided therethrough such that a tip end of an exchange-tube cleaning lance may be inserted into and through each of the exchange-tubes in the heat exchanger by positioning the tip end of the exchange-tube cleaning lance through the open end of each of the exchange-tubes provided through the tube sheet; the heat exchanger exchange-tube cleaning lance positioning system comprising:a three-axis cleaning lance positioning mechanism; a camera mounted to the three axis cleaning lance positioning mechanism; and a lance position computer controller in image signal receiving connection with the camera and in controlling connection with the three-axis cleaning lance positioning mechanism, the lance position computer including a user control interface; the three-axis cleaning lance positioning mechanism including a heat exchanger head flange connecting mechanism for rigidly attaching a non-moving portion of the three-axis cleaning lance positioning mechanism to the heat exchanger head flange of a heat exchanger; a lance depth drive mechanism having a lance connecting structure for connecting an exchange-tube cleaning lance thereto and a lance positioning mechanism for linearly positioning a tip end of a connected exchange tube cleaning lance into and out of an exchange-tube of the heat exchanger when the tip end of a connected exchange tube cleaning lance is positioned in a direct line with a horizontal exchange-tube center coordinate and a vertical exchange-tube center coordinate that corresponds with the flow passageway of the exchange-tube and the front of the open end of the particular exchange-tube; a horizontal lance positioning mechanism in connection with the lance depth drive mechanism in a manner to position a connected exchange tube cleaning lance at a horizontal coordinate corresponding to the horizontal exchange-tube center coordinate for a particular exchange tube; and a vertical lance positioning mechanism in connection with the lance depth drive mechanism in a manner to position a connected exchange tube cleaning lance at a vertical coordinate corresponding to the vertical exchange-tube center coordinate for a particular exchange tube; the lance depth drive mechanism, the horizontal lance positioning mechanism and the vertical lance positioning mechanism all being moveably mechanically connected to the non-moving portion of the three-axis cleaning lance positioning mechanism in a manner such that, when the non-moving portion of the three-axis cleaning lance positioning mechanism is fixedly attached to the heat exchanger head flange, it is possible to position the tip end of a connected exchange tube cleaning lance in a direct line with a separate pair of horizontal and vertical exchange-tube center coordinates that correspond with the flow passageway and the front of the open end of each of the exchange-tubes connected to the tube sheet; the lance position computer controller being programmed to analyze an image signal corresponding to an image of the tube sheet received from the camera after the non-moving portion of the three-axis cleaning lance positioning mechanism is fixedly attached to the heat exchanger head flange in a manner to identify each open end and each flow passageway of each of the exchange-tubes connected to the tube sheet and to calculate and store a separate pair of horizontal and vertical exchange-tube center coordinates relative to the non-moving portion of the three-axis cleaning lance positioning mechanism that correspond with the flow passageway and the front of the open end of each of the exchange-tubes connected to the tube sheet; the lance position computer controller being responsive to input signals from the user control interface in a manner such that the lance position computer controller generates control signals to the lance depth drive mechanism, the horizontal lance positioning mechanism and the vertical lance positioning mechanism of the three-axis cleaning lance positioning mechanism such that a connected exchange tube cleaning lance is positioned into and out of each exchange-tube of the heat exchanger for which a separate pair of horizontal and vertical exchange-tube center coordinates is stored; the lance depth drive mechanism including a force resistance sensor in connection with the lance position computer controller; the lance position computer controller monitoring a resistance signal from the force resistance sensor and stopping the inward movement of the connected cleaning lance when the resistance signal from the force resistance sensor reaches a predetermined threshold value indicating a clogged exchange tube, completely withdrawing the connected cleaning lance, and generating signals to the three-axis cleaning lance positioning mechanism to move the connected cleaning lance to the exchange tube corresponding to the next stored pair of horizontal and vertical exchange-tube center coordinates.