A tunable diode laser absorption spectroscopy (TDLAS) optical head includes a housing configured for attachment to a sight tube attached to a wall of a process chamber. The TDLAS optical head further includes optics within the housing for transmitting, receiving, or transmitting and receiving a laser beam within a process chamber through the sight tube. The TDLAS optical head further includes a photo sensor in the housing positioned to receive light emitted by combustion within the process chamber to which the housing is attached.

A method of monitoring blockage of a sight tube attached to a wall of a process chamber, the sight tube being operatively associated with a TDLAS optical head with a window between the sight tube and the TDLAS optical head. The method includes the steps of providing a photo sensor in the TDLAS optical head, the photo sensor being positioned to receive light emitted by a light emitting process within the process chamber. An emission signal produced by light emitted by the light emitting process within the process chamber being received by the photo sensor is monitored. A determination is made if the emission signal is degrading.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A sight glass for observation of industrial applications using a non-glass lens.

A head assembly for a pulverized coal nozzle includes removeable wear-resistant inserts having vanes. The vanes may be flat or curved to direct a stream of air and pulverized solid fuel particles from the inlet port toward the outlet port. The curved vanes curve in two dimensions to evenly distribute the stream of air and pulverized solid fuel away from the outer surfaces reducing wear and corrosion. The pipe elbow has a removable cover that allows for easy access. The vanes are attached to a wear-resistant replaceable liner thus allowing them to be easily removed and replaced. The wear-resistant liner may be made from several parts for ease of removal and replacement.

A head assembly for a pulverized coal nozzle includes removeable wear-resistant inserts having vanes. The vanes may be flat or curved to direct a stream of air and pulverized solid fuel particles from the inlet port toward the outlet port. The curved vanes curve in two dimensions to evenly distribute the stream of air and pulverized solid fuel away from the outer surfaces reducing wear and corrosion. The pipe elbow has a removable cover that allows for easy access. The vanes are attached to a wear-resistant replaceable liner thus allowing them to be easily removed and replaced. The wear-resistant liner may be made from several parts for ease of removal and replacement.