Abstract: A nozzle assembly for a plasma gun is disclosed, containing an annular coolant passage for extended nozzle life, providing for convenient and low cost replacement of the nozzle member and for improved gun operation. To form the assembly a jacket is disposed about the nozzle member in a predetermined coaxial position. An inner surface of the jacket cooperates with the cylindrical exteriority of the nozzle to define an annular coolant passage. The jacket and the nozzle are in relative slidable relationship such that the nozzle member is removable and replaceable forwardly with respect to the jacket, forwardly being in respect to the direction of the plasma flame. A flange at the forward end of the nozzle member retains the nozzle member from sliding rearward from the predetermined position with respect to the jacket. The jacket has coolant ports for the coolant connecting with the annular passage. A seal such as an O-ring is interposed between the rear portion of the nozzle and the jacket.

Abstract: The position sensor senses the position of a movable finger in relation to a cooperating finger. The position sensor includes a variable reactance device including two cooperating relatively movable reactance elements. One of the reactance elements is mechanically coupled to the movable finger and the other one of the reactance elements is mechanically coupled to a cooperating finger. The relative movement between the reactance elements is effective to vary the reactance of the variable reactance device. An oscillator circuit is connected with the variable reactance device so that the frequency of the oscillator circuit varies to provide a variable frequency output which represents the position of the movable finger with respect to the cooperating finger.

Abstract: A low expansion ceramic composition is represented by the formula Ca.sub.0.5 Ti.sub.2 P.sub.3 O.sub.12 in which up to 100 percent of the Ca is replaced by one or more of the other alkaline earth metals and alkali metals, the alkali metals being selected from the group consisting of Na, Li, K and combinations thereof and substituted in the ratio of two units of alkali metal for each unit of Ca replaced. Up to 100 percent of the Ti is replaced by one or more members selected from the group consisting of Zr, Sn, Nb, Ta and Cr. For each unit of Cr replacement an approximately equal unit of alkali metal is added. For each unit of Nb and/or Ta replacement an approximately equal unit of Na and/or K replaces a unit of Ca. Up to 100 percent of the P may be replaced by Si and/or S. The total of the amounts of Ca, other alkaline earth metals, Li, K, Ti, Sn, Nb, Ta and Cr is greater then zero. Preferably up to 100 percent of the Ca is replaced by Na, and up to 100 percent of the Ti is replaced by Zr or NaCr.

Abstract: A plasma gun has a hollow generally cylindrical anode nozzle member and coaxially disposed therein a cylindrical cathode member, the members co-acting to form an interior passage for plasma forming gas. At one end, within the body of the gun, the passage comprises an annular gas inlet chamber or plenum proximate to the cathode. Progressing in the direction of flow, the passage is defined as an annular space between the cathode and anode members and then continues through the anode nozzle member to the exterior of the gun body. Plasma-forming gas is introduced inwardly through respective inlets, tangentially and radially into the gas inlet chamber. Means are provided for selectively regulating the respective amounts of gas introduced radially and tangentially to thereby determine the degree of vortical flow of gas through the gun.

Abstract: An arc spray gun has a generally frusto-conical head member of electrically insulating material, with the small end facing forwardly in the direction of spray. Wire is fed through a pair of electrically conductive tubular wire guides containing pressure contact means that extend through the head member and converge to contact the wire ends for arc formation and melting of the metal. A gas jet nozzle provides compressed gas for atomization and spraying of the molten metal. A first gas cap is disposed coaxially on the head with rear and forward gas seals so as to define an annular gas chamber. A secondary gas is supplied to the annular chamber, and the first gas cap has a pair of diametrically opposite orifices therein for directing the secondary gas from the chamber to modify the molten metal spray in a fan shape. The orifice may have elongated cross sections to produce a rough coating surface if desired.

Abstract: A plasma generating device, and in particular a duoplasmatron ion gun, is disclosed that is air cooled, high vacuum compatible and hence very clean with a stable ion current output. The device is mounted to a standard type flange held at ground potential without the necessity of subsequent high voltage isolation. Cooling is achieved with cooling fins and a fan inside a housing in which the duoplasmatron is mounted. A mounting structure includes a vacuum tight ceramic ring brazed between the mounting flange and the gun body. The ceramic ring is located with respect to high permeability magnetic components and a magnetic coil to facilitate a magnetic field for focusing the plasma, allowing the coil to be referenced to ground potential while the gun is maintained at high voltage. A ceramic chamber containing ceramic pellets is located in the plasma-forming gas inlet duct to prevent high voltage electrical discharge in the gas duct.

Abstract: A gas distribution ring for a plasma gun comprises a ring member with two sets of gas inlet orifices extending from the outer surface inwardly through the ring member. The outer surface has an undulated groove for an O-ring formed therein, and the orifices are positioned with respect to the undulated O-ring such that one set of orifices are isolated on one side of the O-ring and the other set of orifices are isolated on the other side of the O-ring. In a preferred embodiment the orifices of one set are radial with respect to the axis of the ring, and the orifices on the other side of the undulated O-ring have a tangential component to provide vortical gas flow in the arc region of the gun. The gas distribution ring positioned in the plasma spray gun permits a simple choice between radial and vortical flow in the arc region of the gun, without alteration of the gun.

Abstract: A flame spray material for producing a thermally shock and erosion resistant ceramic coating is comprised of a homogeneous ceramic composition formed of zirconium oxide, yttrium oxide and titanium oxide. The composition is preferably in the form of composite particles each of which contains a plurality of subparticles of each of the oxide constituents bonded with an organic binder.

Abstract: It has been shown that the use of a shutter to cut off the light beam entering the optical system of a fluoresence spectrophotometer will reduce UV deterioration of the components in the optical system. This invention discloses how control of the output of the light source by lowering its arc current when the shutter is closed can add significant improvement to the functioning of such a shutter system.

Abstract: An apparatus for monitoring a plasma torch includes a dedicated photometer which produces a signal representative of the temperature of a quartz tube of the torch, which signal can be used to reduce the temperature thereof.

Abstract: A multi-level priority micro-interrupt controller for a micro-program controlled computer handles a plurality of interrupt signals at a plurality of levels of priority, wherein only one interrupt signal for each level of priority may be active at any moment. When an interrupt occurs which has a higher priority than that of the interrupt currently being handled, the control store address of the next instruction to be executed is stacked and the interrupt handler subroutine for the higher priority interrupt is initiated. When an interrupt occurs which has a lower priority than that of the interrupt currently being handled, it is queued. After an interrupt has been handled, the stack is popped and execution is resumed at the control store address at the top of the stack. The control store address of the interrupt handler subroutine for a particular interrupt is decoded from the interrupt signals in two parts, the second part also being used to control the branching to the interrupt handler subroutine.

Abstract: Wavelength related interference artifacts may appear superimposed on the output data curve of a scanning spectrophotometer utilizing a photodiode array as photometric detector. These may be suppressed by interposing a transparent optical element in the optical beam adjacent to its incidence on the array. Such an element should have no optical power along an axis parallel to the wavelength axis of the array and should provide varying phase displacement of the rays of the beam transverse to the wavelength axis. Several forms such an optical element may take are disclosed.

Abstract: An impedance matching network for continuously and automatically maximizing RF power transfer to a plasma emission torch includes a dual phase detector network. Signals from the detector network control, via a control unit, a variable impedance network.

Abstract: A memory refresh circuit controls the refreshing of dynamic RAM included in a system wherein a control store outputs micro-code instructions to control the system operation in response to sequences specified by a sequence and interrupt logic circuit (SIL). A counter transmits certain counts of system machine cycles to an array logic device. In response to one count, the array logic device generates a memory refresh request signal which is applied to a RAM address logic circuit (RAL). The RAL monitors the micro-code instruction output at each machine cycle to determine whether the instruction will access the dynamic RAM during that machine cycle, and if no memory access is detected, the RAL generates a signal to initiate a memory refresh operation, which operation requires two machine cycles to complete.The array logic device also monitors the micro-code instructions to determine if and when a refresh operation was initiated.

Abstract: An assembly for positioning an optical element, includes a frame member having a base member affixed thereto, which base member carries an optical element rigidly affixed thereon. The base member is mounted to the frame member via a plurality of tilting means which permit the base member to be tilted with respect to the frame member in at least two orthogonal planes and thereby allows the precise alignment of the optical element.

Abstract: A new and improved controller for creating a linear gradient dual solvent flow pattern in a dual pump liquid chromatography system wherein one pump pumps one solvent and the other pump pumps the second solvent, the controller comprising a clock for producing a timing signal; digiswitches for providing first and second digital signals representative of initial and final values for one of two solvents; a difference circuit for producing a third digital signal representative of the difference between the initial and final values; a digiswitch for providing a fourth digital signal representative of the time duration of the linear gradient; a binary divider for regulating the timing signal to produce a signal proportional to the fourth digital signal; a binary rate multiplier for proportioning the regulated timing signal to the third digital signal; circuitry for producing a fifth digital signal from the proportional regulated timing signal, whereby the fifth digital signal represents the dividend of the third dig

Abstract: In a spectrophotometer having an optical beam chopped into dark and light segments, a computer controlled system is described for determining background signal due to stray light, photomultiplier dark current, offsets of photometric amplifiers and other components, and the like and for subtracting this background signal from the overall signal so as to leave only the desired light measurement. The same computer system also sets the signal level automatically for highest resolution. Furthermore, the same computer acts as an analog to digital converter by successive approximation to supply the photometric signal to the microprocessor unit. Since the same components are involved in all these functions both analog and digital offsets of the components are automatically cancelled.

Abstract: An apparatus for controlling a plasma discharge includes a light gathering tube remotely directed at the plasma discharge. The gathered light is transmitted, via a filter optic light pipe, to a detector that produces a signal that is compared with at least one reference signal. After comparing the signals the RF power to the plasma torch is either interrupted or continued.

Abstract: A shutter mechanism which includes simultaneous translation of a shutter in two planes of motion prolongs the life of the sealing material of the shutter as well as ensures that, when open, an optical beam passes through a sample compartment without interference or disruption. A further advantage of such a mechanism lies in the positive sealing of a port with sufficient pressure applied via the shutter plate to prevent vapor or fluid communication across the port.

Abstract: A flame spray material for producing a low thermal conductivity ceramic coating is comprised of a homogeneous ceramic composition formed of zirconium oxide, cerium oxide and yttrium oxide. The composition is preferably in the form of composite particles each of which contains a plurality of subparticles of each of the oxide constituents bonded with an organic binder.