Abstract: There is disclosed a method and apparatus for the corrosion condition evaluation of unbonded prestressing elements in post-tension concrete structures. The method involves locating a prestressing element in the structure and providing at least two openings in the structure at positions along the length of the element. One of the openings is an inlet port and the other is an outlet port, each of the ports permitting communication with the gaseous environment within a conduit surrounding the prestressing element. The gaseous environment is accessed through the outlet port by extracting a sample of gas therethrough. The sample is then measured to determine its humidity and thereby evaluate the corrosion condition of the prestressing element between the inlet port and the outlet port. A method and apparatus is also provided for the on-site corrosion protection of unbonded prestressing elements whereby the gaseous environments within the conduits are cyclically pressurized with a dry gas.

Abstract: A device for creating a corrosive condition and monitoring that condition, adapted for use in active fluid heat exchangers, has a sealed tube having corrosion sites spaced apart on its exterior. Structure positioned on the outside of the tube at the corrosion sites provide crevices for retaining corrosive sludges in contact with the corrosion sites. The interior of the tube is pressurized with a gas to stress the tube thereby accelerating corrosion of the surface. Heat is provided to the corrosion sites from within the tube when placed within a fluid reservoir, such as the secondary side of a fluid heat exchanger. The heat concentrates corrosive chemicals at the corrosion sites, also accelerating corrosion. Electronic probes can be mounted in proximity to the corrosion sites for real time monitoring of the progress of corrosion.

Abstract: A system for monitoring abnormalities in a heat exchanger having heat-exchange tubes for heating feed water with extraction steam, an inlet and an outlet for the feed water, and a drain cooling zone, includes a process input, an apparatus for calculating the differential pressure between the feed water pressures at the inlet and outlet, an apparatus for computing the heat exchanging performance of the heat exchanger, and judgement apparatus for monitoring the differential pressure and the heat exchanging performance, thereby judging the presence or absence of scale accretion within the heat exchanger end, whenever scale accretion is present, judging the specific locations of the scale accretion in the inner and outer surfaces of the heat-exchange tubes, fluid flow distribution passageways and devices other than the heat-exchange tubes.

Abstract: Disclosed is a method for monitoring biofilm formation which comprises incorporating in an aquatic system, a sampler apparatus comprising a duct 1 having a port 5 in which is retained a stud 17 having a test surface 19 which lies flush with the wall of the duct. The invention can also be used to detect Legionellae bacteria.

Abstract: A long duration ash probe includes a pressure shell connected to a port in a combustor with a sample coupon mounted on a retractable carriage so as to retract the sample coupon within the pressure shell during sootblowing operation of the combustor. A valve mounted at the forward end of the pressure shell is selectively closeable to seal the sample coupon within the shell, and a heating element in the shell is operable to maintain the desired temperature of the sample coupon while retracted within the shell. The carriage is operably mounted on a pair of rails within the shell for longitudinal movement within the shell. A hollow carrier tube connects the hollow cylindrical sample coupon to the carriage, and extends through the carriage and out the rearward end thereof. Air lines are connected to the rearward end of the carrier tube and are operable to permit coolant to pass through the air lines and thence through the carrier tube to the sample coupon so as to cool the sample coupon.

Abstract: The present invention is drawn to soil erodibility testing utilizing: an outer backwater tank, which during testing is filled with water; an inner liner positioned at least partially within the outer backwater tank for minimizing return turbulence and providing a mount for either a feed tube or pin profiler means, and; a feed tube having a nozzle thereon, which is positioned within the interior of the inner liner. Water is forced through the feed tube and nozzle, into contact with soil to be tested, so that at least a portion of the soil is removed by erosion. The volume of soil removed by erosion is determined based on the differences between an initial soil profile and an eroded soil profile, which may be measured with a pin profiler means.

Abstract: A weather-fastness test method utilizing a novel sample holder and constituted by the steps of fixing the sample to the holder which is provided with metal coils the shape of which varies in accordance with the variation in the temperature of the ambient air and the radiation heat from a light source and which are connected so as to apply a force to the sample as the temperature changes, placing the sample under predetermined conditions, e.g. exposing the sample to radiation by light, to air having a temperature and humidity of predetermined levels, and to rain, while the sample is under repeated tension, compressive force and/or bending stress due to the variation of the shape of the coils and imparted to the sample, and then evaluating the weather-fastness resistance of the sample.

Abstract: A corrosion detector for use with a sealless centrifugal pump. The corrosion detector having a corrosion coupon at one end of the detector. The corrosion coupon being formed of the same material as the pump containment shell and having a thickness approximately two thirds the thickness of the containment shell. The corrosion detector is preferably installed in a bore in the pump discharge flange such that the corrosion coupon is exposed to the velocity of the pumped fluid. A detector is mounted within the corrosion detector to detect any leakage of the pumped fluid through the corrosion coupon. The corrosion coupon is designed so that this leakage will occur before the containment shell has failed or begun leaking due to corrosion.

Abstract: A method and apparatus are provided for conducting meso-scale rainfall simulations and runoff collections. The apparatus includes a system for continuously applying to a test plot simulated rainfall having a droplet size spectrum, an impact velocity, a spatial uniformity and an intensity simulating natural rainfall. Additionally, the apparatus includes a collector assembly for collecting runoff from the test plot for analysis. In accordance with the present method, natural rainfall for a geographic area including the test plot is studied in order to determine the drop size spectrum, drop impact velocity, spatial uniformity and intensity of the rainfall. A sprayer or irrigation head is then selected providing a droplet size spectrum closely resembling that of the natural rainfall to be simulated. Next, the spacing between and relative height of the irrigation heads is adjusted to ensure that the spatial uniformity, intensity and drop impact velocity resemble that of the natural rainfall to be simulated.

Abstract: An apparatus for measuring the diffusion of hydrogen atoms from a second surface to a first surface of a ferrous metal body in order to monitor the magnitude of corrosion occurring at the second surface. The apparatus comprises a chamber-defining member which can be sealed to the first surface of the body so as to define with the first surface a sealed chamber. The chamber-defining member is constructed of material sufficiently flexible that upon evacuation of the sealed chamber the chamber-defining member deflects toward the first surface to reduce the chamber volume. The apparatus provides a connection for attaching an evacuating pump which is used to evacuate substantially all of the contents of the chamber. A valve is provided to isolate the evacuated chamber from the evacuation pump so that hydrogen atoms, generated as a result of corrosion of the second surface, migrate through the body and exit the first surface within the chamber and combine to form hydrogen molecules which collect in the chamber.

Abstract: A fluid sensor for heat exchanger system includes a supporting device such as a tubular hose fitting for mounting the sensor in the system so that heat exchanging fluid circulated in the system comes into contact with the sensor. A window or sight glass is mounted in the supporting device along with corrodible separating means interposed between the sight glass and the heat exchanging fluid. A visual indicator such as a movable flap or a colored ball can be viewed through the sight glass when the separating means is ruptured or broken by corrosion. The viewing of the indicator provides an indication that the heat exchanging fluid has reached a certain corrosive state and requires replacement or treatment. In a preferred embodiment, the separating means is a metal diaphragm spaced from the sight glass.

Abstract: The installation comprises a selective liquid-feeder assembly, a selective gas-feeder assembly for feeding gas under pressure, a mixing and preheating assembly itself comprising a vaporizing stage, a mixing stage, and a preheating stage to raise the gas-vapor mixture to a temperature of about 150.degree. C. to about 300.degree. C., and a distributor assembly for distributing the flow of gas-vapor mixture to a plurality of high temperature generalized corrosion test circuits. Each test circuit comprises a reactor including an intermediate preheater stage for preheating the gas-vapor mixture applied to the reactor to a temperature of about 400.degree. C. to about 600.degree. C., and a final heater stage containing at least one sample of material to be tested which sample is put into contact with the gas-vapor mixture flow from the intermediate preheater stage, and raised in the final heater stage to a temperature lying between about 700.degree. C. and about 850.degree. C.

Abstract: The present invention is drawn to soil erodibility testing utilizing: an outer backwater tank, which during testing is filled with water; an inner liner positioned at least partially within the outer backwater tank for minimizing return turbulence and providing a mount for either a feed tube or pin profiler means, and; a feed tube having a nozzle thereon, which is positioned within the interior of the inner liner. Water is forced through the feed tube and nozzle, into contact with soil to be tested, so that at least a portion of the soil is removed by erosion. The volume of soil removed by erosion is determined based on the differences between an initial soil profile and an eroded soil profile, which may be measured with a pin profiler means.

Abstract: A corrosion monitoring system having one or more anode elements made of a suitable anodic material that corrodes preferentially with respect to the structure being protected. The resistance of each anode wire is continuously or periodically monitored. The presence of moisture between an anode and the structure being monitored creates a current path and causes galvanic corrosion. The anode wire will begin to corrode, but the structural members will remain uncorroded until the anode has been completely consumed. The monitoring system uses the rate of change in anode resistance to extrapolate a prediction of the time remaining before the structure being protected begins to corrode.

Abstract: The electrolytic resistivity leak detector comprises the method of electrical resistivity to measure the gradual intrusion of aggressive chemicals into the wall of a plastic or fiber reinforced plastic vessel. This device and method includes the use of electric sensors within the wall of the vessel. The sensors provide an electrical circuit as the chemicals permeate through the wall and make contact with the sensors. A microammeter is included as an instrument to monitor and register the degree of electrical resistivity caused by the chemical intrusion.

Abstract: Particles in a fluid stream are detected by utilizing one or more probes each provided with at least one measuring or erosion element. The probe is placed in the fluid stream, and the particle content is quantitatively determined by measuring changes of electrical resistance as a function of erosion of the measuring element due to contact with particles moving in the stream. The probe may be equipped with a measuring head having a V-shaped configuration directed upstream, and the two planar surfaces defining the V-shape may each be equipped with one or more measuring elements.

Abstract: A method and apparatus for using a coated piezoelectric crystal to monitor and report corrosion in terms recognized as conforming to an industry standard is disclosed. The present invention provides a method of and system for monitoring corrosion in a corrosive atmosphere, comprising and carrying out the steps of exciting in the atmosphere a crystal, coated with a corrodible metallic substance and having a known vibration frequency; measuring the change in the frequency of vibration resulting from corrosion of the corrodible substance during each of a plurality of intervals of time, including a reference interval and at least one subsequent measurement interval; generating a thickness signal representing the thickness of corrosion corresponding to the measured change in frequency during the measurement interval; and converting the corrosion thickness signal for the measurement interval to a reference signal representing the thickness of corrosion accumulated during the reference interval.

Abstract: The present invention is drawn to soil erodibility testing utilizing: an outer backwater tank, which during testing is filled with water; an inner liner positioned at least partially within the outer backwater tank for minimizing return turbulence and providing a mount for either a feed tube or pin profiler means, and; a feed tube having a nozzle thereon, which is positioned within the interior of the inner liner. Water is forced through the feed tubed and nozzle, into contact with soil to be tested, so that at least a portion of the soil is removed by erosion. The volume of soil removed by erosion is determined based on the differences between an initial soil profile and an eroded soil profile, which may be measured with a pin profiler means.

Abstract: The elemental composition of a material exposed to hot gasses and subjected to wear is determined. Atoms of an elemental species not appearing in this material are implanted in a surface at a depth based on the maximum allowable wear. The exhaust gasses are spectroscopically monitored to determine the exposure of these atoms when the maximum allowable wear is reached.

Abstract: A fluid sensor for heat exchanger system includes a supporting device such as a tubular hose fitting for mounting the sensor in the system so that heat exchanging fluid circulated in the system comes into contact with the sensor. A window or sight glass is mounted in the supporting device along with corrodible separating means interposed between the sight glass and the heat exchanging fluid. A visual indicator such as a movable flap or a colored ball can be viewed through the sight glass when the separating means is ruptured or broken by corrosion. The viewing of the indicator provides an indication that the heat exchanging fluid has reached a certain corrosive state and requires replacement or treatment. In a preferred embodiment, the separating means is a metal diaphragm spaced from the sight glass.

Abstract: In combination with a steam generator having a plurality of generator tube support plates, each generator tube support plate having a plurality of openings and a plurality of generator tubes, each tube passing through aligned openings in the support plates, a corrosion monitoring system is provided including a mockup probe, comprising a probe tube support plate having an upper side and a lower side and having substantially the same thickness and being constructed of substantially the same material as the generator tube support plates, having at least one opening of substantially the same size and shape as the openings of the generator tube support plates; at least one probe tube having an upper end and a lower end and having substantially the same diameter as the generator tubes and being constructed of substantially the same material as the generator tubes, the probe tube passing through the opening of the probe tube support plate; and wherein the mockup probe is adapted such that it may be inserted and seal

Abstract: A coupon holder apparatus for measuring the rate of corrosion caused by formation fluid contained downhole in a borehole. The apparatus is useful when used in conjunction with a pumping unit of the type having a pump located at the bottom of a borehole and a sucker rod string extending downhole through a tubing string to actuate the pump. The apparatus has a main body which is connected in the rod string and suspended downhole in the borehole where it is in contact with the well fluids. An axial chamber is formed within the main body and radial ports extend through a sidewall of the main body to communicate the axial chamber with the borehold fluids.

Abstract: A sidestream pipeline, adapted for attachment to a mainstream pipeline, is provided with end closures to permit the introduction of mechanical cleaning devices or chemical compositions to the sidestream pipeline to remove biofilm and treat corrosion-causing constituents; also provided are a plurality of removable coupons closely fitting within holes in the sidestream pipeline wall, and duplicating the material and configuration of the interior surface of the mainstream pipeline. The coupons can be individually withdrawn from the lowermost surface position during cleaning operations to avoid contact with the mechanical cleaning devices and can be isolated from teh chemical treatment. The coupons are removable for laboratory study and analysis.

Abstract: An economical, corrosion-resistant, wireline set and retrievable, downhole coupon holder is disclosed that has a non-metallic, elongated member having recessed slots and a mounting means for mounting the coupons within the recessed slots. Preferably, there are six pairs of slots, with each pair of slots being on opposite sides of the elongated member. Each pair of slots shares a common mounting means that fixes the ends of coupons within that pair of slots.

Abstract: A method of monitoring thinning of pipe walls in a piping system including selecting locations to be monitored, normally those pipes particularly susceptible to thinning from erosion/corrosion, boring holes in the outer surfaces of the pipes at the selected locations to depths greater than the thickness at which the pipes will rupture to leave predetermined residual wall thicknesses between the ends of the holes and the inner surfaces of the pipe walls, inserting tracer materials in the holes to be released in the pipes when pipe wall thinning exceeds the residual wall thicknesses of the holes, and determining the presence or absence of tracer materials in the holes to permit pipe wall thinning to be determined prior to pipe rupture allowing repair or replacement during scheduled downtime of the piping system.

Abstract: A method and an apparatus for the detection of corrosion, pitting or the like in pipelines is proposed and measured results produced in an appropriate manner are digitally converted, linked with measured values concerning the place and azimuth of the individual sensors to form individual blocks, which are intermediately stored to form larger units and are finally stored in a mass store.

Abstract: A wear sensor provided with a block incorporating one or more optical fibers for indicating that wear has occurred to the block, on the basis of a fact that the fibers have been severed on account of wear of the block.

Abstract: A method and apparatus for measuring decreasing thickness of the refractory lining of a high pressure, high temperature, water cooled reactor wall, such as a high pressure gasifier, during aggressive corrosion attack using a pulse-echo ultrasonic probe inserted in the wall, which will corrode at approximately the same rate as the wall of the reactor.

Abstract: A method of monitoring thinning of pipe walls in a piping system including selecting locations to be monitored, normally those pipes particularly susceptible to thinning from erosion/corrosion, boring holes in the outer surfaces of the pipes at the selected locations to depths greater than the thickness at which the pipes will rupture to leave predetermined residual wall thicknesses between the ends of the holes and the inner surfaces of the pipe walls, inserting tracer materials in the holes to be released in the pipes when pipe wall thinning exceeds the residual wall thicknesses of the holes, monitoring fluid flow through the piping system to sense the presence of tracer materials in the fluid, and determining the location of the hole from which a sensed tracer material was released to permit pipe wall thinning to be determined prior to pipe rupture allowing repair or replacement during scheduled downtime of the piping system.

Abstract: An apparatus for establishing a flow of fluid mass, such as gas, having steady uniform flow at a test section area of the closed loop chamber. The chamber provides a constant and reproducible atmosphere in which the rates of electrolytic metal migration and corrosion can be determined as a function of pollutant concentration and humidity content velocity. The overall length to diameter ratio (L/D) of the chamber is reduced in comparison to conventional chambers.

Abstract: A sensing probe having a hollow tube for disposition in a flow stream is provided with an internal stiffening rod. A volume between the stiffening rod and the inner surface of the tube communicates with an open end of the sensing probe. In one embodiment, oppositely directed spiral grooves are formed in the surface of the stiffening rod to define the volume. A method of manufacturing the sensing probe includes first inserting a stiffening rod into a tube and then turning the tube to a desired wall thickness.

Abstract: Refractory erosion detection devices are positioned in the refractory lining of metallurgical vessels, such as ladles and refractory stirring plugs incorporated in such vessels through which stirring gas is directed, comprise metal rods positioned in the upper or outer portions of the refractory bodies with their inner ends spaced from the opposite surfaces of the refractory body so that molten metal introduced into the metallurgical vessels erodes the refractory bodies and the metal rod to a point where the complete erosion and absence of the metal rods visually indicates the pre-determined thickness of the remaining refractory bodies indicating the need of replacement of the same.

Abstract: A method of determining the degree of embrittlement of low alloy steel with high accuracy and good reproducibility, comprising the steps of bringing the low alloy steel into contact with an aqueous solution of an aromatic compound having a nitro group and at least one of a hydroxyl group and a carboxyl group, measuring an open circuit potential of the steel, and determining the degree of embrittlement of the low alloy steel caused by the thermal history of the low alloy steel using the measured value.

Abstract: A corrosion coupon holder for inserting and removing a coupon from the interior of a pipeline while under pressure has an elongated housing with a threaded connection at one end and a removable closure device at the other end, the housing connection to be attached to a pipe entry valve which is connected as a branch to the pipeline. The housing other end also carries a guide body having a bore which guidingly and sealingly receives a rod for inserting a coupon having a safety stop element at one end to hold the coupon, the guide body having a split collet associated with the bore with a locking screw mounted to act on the collet to fixedly clamp the rod in the bore of the guide body and the housing having a bleeder valve communicating with the interior to relieve pressure from within such interior.

Abstract: A corrosion coupon anchoring system for positively positioning a corrosion monitoring coupon in the production flowpath downhole in a producing well. Preferably cylindrical coupons are held firmly within a cylindrical housing suspended out of contact with any other metallic surface. An adaptor threadingly engages the cylindrical housing to a conventional locking mandrel that is locked in place to a nipple positioned in the tubing string. The minimum internal dimension of the coupon holding section is not less than the minimum internal dimension of the locking mandrel so as to minimize flow restriction introduced by the anchoring system.

Abstract: There is disclosed a novel fouling and corrosion test assembly including a metallic tube having a heating element embedded in a heat conductive material for controlled heat input and with a thermocouple to measure wall temperature of the tube, and a metallic sleeve disposed about a predetermined portion of the metallic tube whereby the fouling and corrosion test assembly is disposed within conduit and valve assemblies in fluid flow communication with a fluid to determine corrosion rate by weight loss of the metallic sleeve under controlled heat input, temperature conditions and fluid flow rates for a predetermined time period.

Abstract: A wear sensor system for detecting erosion, corrosion and wear of a component is disclosed. Conductive loops of a sensor probes are embedded at spaced locations through the component. As erosion, corrosion or wear of the component is sustained, each conductive loop is subjected to such wear condition in turn and is interrupted only as the component is worn away at its particular location. The continuity status of each loop is evaluated periodically, with an electrical closed circuit condition indicating structural integrity at that particular loop location, and an electrical open circuit condition indicating such a wear condition.

Abstract: An apparatus for moving an object in an isolated environment may be employed as a high pressure and temperature facility for testing steam generator tubes. A tube to be tested extends through an opening in a plate that is mounted in a test vessel. The vessel is partially filled with water having selected contaminants, and heated water under high pressure is circulated through the tube to raise the temperature and pressure within the vessel. A lever arm having an inner end and an outer end extends through an opening in the test vessel. A vibration-coupler connects the inner end of the arm to the tube under test, and a fulcrum-former operationally connects an intermediate portion of the arm to the test vessel. The outer end of the lever arm is connected to a plug element which is shaken, so that the arm pivots about a fixed point at the fulcrum-former and the vibration-coupler moves the tube under test with respect to the plate.

Abstract: A probe rod is inserted into a water main through a corporation cock. The rod has a plurality of transverse passages parallel to one another and aligned in the direction of flow. Within these transverse passages, in flush relationship to the passage walls, are inserted removable sampling rings. All but one of the rings are of the same material as the inner wall of the main. The remaining ring, used as a control, is a synthetic resin ring. The flush relationship prevents the formation of turbulent eddies at the ends of the rings. Consequently, microbial growth conditions on the rings themselves reliably simulate conditions on the interior wall of the main.Within a tubular extension on the exterior of the corporation cock an O-ring seal is provided. The length of the extension, and the position of the seal, are such that the probe rod can be partially withdrawn beyond the corporation valve without causing any of the transverse passages to pass through the O-ring.

Abstract: A sensor apparatus cooperates with an electrical system capable of delivering power to and receiving signals from the sensor. A cable housing insulated wires is connected to the sensor and disposed in proximity to a fluid possibly containing a corrosive impurity. Corrosion detecting elements are connected to the wires and are immersed in the fluid possibly containing the impurity. Further, the elements are provided with breakable regions fabricated to corrode in the presence of the corrosive impurity. To facilitate fracture, the elements are loaded in tension so the breakable regions will fracture rapidly in the presence of corrosive impurities, to thereby send an electric signal to remote electrical equipment to indicate the presence of at least one impurity.

Abstract: A method and apparatus for monitoring corrosive effects of fluid in a well, for use with a well tubing mandrel having a main bore and a side pocket offset from the main bore. The mandrel also has a slot along the length of the side pocket adjacent the main bore, and the exterior surface of the mandrel is free of apertures. A corrosion coupon is mounted within a notch on the side of a carrier, and the carrier is placed into the side pocket for a specified time period. The carrier is oriented to position the coupon within the slot. The carrier is then removed from the well and the coupon is inspected.

Abstract: Techniques and apparatus are described for measurement of corrosion of drill pipe in a well bore during drilling. The techniques involve the use of a test coupon attached to the external surface of a drill string. In a preferred embodiment the test coupon comprises a metal plate mounted in an insulating material such as plastic. The test coupon is preferably secured within a recess in the external surface of a sub connected between segments of a drill string.

Abstract: Some forms of corrosion, and inter-granular attack in particular, occur without significantly altering the bulk dimensions of the body attacked. Where elastic properties are changed, this is detected by a sensitive ultrasonic inspection based upon the resonant frequency or frequencies with which the ultrasonic signals reverberate within the body. Resolution is improved by gating out the first, top, surface reflection and by swept gain control through the gating period.

Abstract: The invention provides a sensing device and method to determine irregularities of a pipeline wall arising from corrosion, pitting, gouges, scale and deposits, and dents causing out of round conditions. This sensing device may be carried through a pipeline by a pipeline pig and comprises radial, movable spring-loaded sensing fingers adapted to continuously contact the pipeline inner surface, said sensing fingers preferably being secured to a fluid-tight drum. The sensing fingers are acoustically connected to one or more microphones, which may be confined within the interior chamber of the fluid-tight drum. The microphones, in turn, are electrically connected to a recording device for recording the audio signal the sensing fingers make as they move through the pipeline.

Abstract: An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

Abstract: Method and apparatus for detecting deterioration of a replaceable liner in a pump transporting an electrically conductive fluid medium. A conductive component is isolated, during normal operation, from the conductive fluid medium by the electrically insulative liner. The conductive component is positioned at a predetermined location relative to the liner such that upon a selected degree of wear of the liner, an electrical circuit is completed upon contact of the fluid medium and the conductive member.

Abstract: A process for monitoring the wear of a refractory lining of a metallurgical furnace wall during use of the furnace, it is sought to improve the reliability and accuracy of the measurement comprising the following steps:(1) arranging a bar of ceramic material in the wall so that the bar has an inner end at the inner face of the lining and extends to the exterior of the wall, the bar thus being subjected to wear at its inner end as the lining wears and determining(2) the position of the worn inner end of the bar ultrasonically by generating ultrasonic pulses in the bar and detecting the reflection of the pulses from the worn inner end of the bar.

Abstract: A method and apparatus are disclosed for monitoring the condition of the stirring block and solid plug therein as incorporated in the normal refractory brick lining of a molten metal ladle to provide a structure through which gas can be introduced into the molten metal, the method utilizes heat sensors and/or Hall Effect transducers embedded in the stirring block and/or solid plug therein in connection with apparatus providing a warning of critical wear and/or erosion in the gas stirring devices by the molten metal in the ladle. An appropriately shaped stirring block provides for the positioning of some of the normal refractory brick lining of the ladle partially thereover so as to eliminate loosening or cracking of the stirring block and the undesirable escaping of molten metal from the ladle.

Abstract: A conductivity sensor for placement on a curved steam turbine component within the steam path. The sensor includes a metal foil base over which is deposited an electrically insulating layer such as glass. The base and insulating layers are of such thickness so as to be flexible so as to conform to the curved surface. An electrode array is deposited upon the insulating layer and spaced so as to accommodate for deposition of steam impurities onto the insulating layer. Flexible links connect the electrodes to electrical leads so that conductivity indications may be obtained.

Abstract: In a method for determining and evaluating nozzle erosion rate, an eroding ozzle and a non-eroding nozzle are employed in a dual nozzle arrangement to receive a balanced thrust and flow rate from a common solid propellant grain of a solid propellant rocket motor when initially fired. When erosion of the eroding nozzle begins an increase in throat area results and the mass discharged through throat increases thereby causing an imbalance in thrust. The erosion is correlated to the mass flow rate of the solid propellant rocket motor by the mathematical relationships, F.sub.2 P.sub.C.sbsb.2 (A.sub.t.sbsb.2 +.DELTA.A.sub.t.sbsb.2)C.sub.F.sbsb.2, wherein F.sub.2 is force, P.sub.C.sbsb.2 is chamber pressure, A.sub.t.sbsb.2 is throat area, .DELTA.A.sub.t.sbsb.2 is change in throat area due to erosion, and C.sub.F.sbsb.2 is the thrust coefficient.