Repair fitting for NOx and particulate matter sensors

Abstract

The present invention is an apparatus and method which allows for repair cost reduction in the event an exhaust system becomes damaged during replacement of a NOx or particulate matter sensor. Replacement of only the sensor mount, rather replacement of an entire emissions after-treatment component can return a unit to service with a fraction of the downtime and expense of traditional system replacement. This is accomplished through a developed removal technique for the damaged integral mounting, in conjunction with the installation of a service replacement fitting which has now been developed to embody a new form as a weldable replacement part. This invention allows for the benefits of cost savings and reduced repair downtime, as well as a reduced consumption of rare earth metals used in the construction of emissions after-treatment devices.

1 . A component to repair an exhaust system construct inside of which an oxides of nitrogen (NOx hereinafter) or particulate matter sensor's threads have been damaged, comprising: a replacement embodiment counterbored weld fitting into which a NOx or particulate sensor is installed, said fitting further comprising;
 a) a weldable ferrous machined part with internal ISO threads to receive the replacement NOx or particulate matter sensor of the type which comprises an externally threaded sensor nut, compression seat, and a sensing probe that would protrude through the aforementioned fitting once installed,   b) said internal threads leading to or near a counterbored surface against which sealing will occur upon tightening of the aforementioned sensor's nut,   c) a smaller hole penetrating the center of the internal structure to create the counterbore through which a sensor's probe will protrude to reach the internal space of its respective emissions after-treatment construct or conduit through which exhaust is transferred from a combustion engine.   
     
     
         2 . A method of repair utilizing the replacement weld fitting of  claim 1 , comprising:
 a) heating the damaged integral mounting with an oxygen acetylene torch to the melting point of its base material,   b) simultaneously applying torque by means of a pipe wrench or other suitable tool,   c) twisting said tool until the integral mounting structure is cleanly severed from the exhaust system construct,   d) affixing the replacement fitting of  claim 1  to said exhaust system construct by means of appropriate welding or brazing practices, whereupon a replacement NOx or particulate matter sensor will be installed in said replacement fitting.