Abstract: A system which is especially useful in controlling fuel gas flow in a flame atomic absorption spectrophotometer includes a master fluid flow path and a slave fluid flow path connected to receive fluid from a common source connection. A first valve is connected in the master path for controlling the rate of fluid flow therein. A first orifice device is connected in the master path between the common source connection and the first valve. The slave path includes a pressure responsive fluid flow modulating valve having a control connection to the master path between the first orifice device and the first valve. A second orifice device is connected in the slave path between the common source connection and the flow modulating valve. The flow modulating valve is operable in response to the fluid pressure in the master path as reduced by the first orifice device and in response to the fluid pressure in the slave path as reduced by the second orifice device to control the fluid flow through the slave path.

Abstract: The flame in a flame atomic absorption spectrophotometer is shut down while using nitrous oxide as the oxidant, without shifting to a different oxidant such as air, by flooding the burner with a substantial excess of nitrous oxide to blow out the flame.

Abstract: A self sprung holder device for a hollow cathode lamp of the type useful as a spectral radiation source for atomic absorption spectrometers. The holder is constructed from a sheet of flexible material bent along two lines to form an elongate tapered triangular housing open at one angle. An adjustment means is pivotally mounted at the rear or larger triangular opening of the housing. The adjustment means includes two thumb screws and a projecting arm member for aligning the lamp along two axes of movement with the front end portion of the lamp being pivoted about one or more integral housing fulcrum points.

Abstract: A flame atomic absorption spectrophotometer burner apparatus for burning a fuel such as acetylene as one essential gas in the oxidant such as nitrous oxide as another essential gas includes a system for safely changing oxidants between air and nitrous oxide during start up. The system has a pressure sensor for sensing the pressure of at least one of the essential gasses, and a valve selectively operable in response to the pressure sensor for effecting the supplying of air as the oxidant and continuing to supply air as the oxidant when the pressure of the essential gas is low and for selectively switching to nitrous oxide as the oxidant only when the pressure of the essential gas is high.

Abstract: An automatic gas flow safety device or system is provided for use with an atomic absorption spectrophotometer burner. Generally speaking, a dual function pneumatic and electrical safety device is described which provides for a cut-off of the (acetylene) gas to the burner, upon monitoring an unacceptable air flow or electrical condition, to avert possible flash-backs at the burner. The invention basically comprises a pneumatic and electrical actuated means to control the on/off flow of gas to the burner determinative on the status of the air pressure and electrical power to the system.