Abstract: To inspect the integrity of pressurization holes in nuclear fuel rod final end plugs, quality assurance apparatus includes an adapter providing a test chamber into which an end plug is inserted. Instrument gas is introduced into the test chamber through an inlet port for flow to the atmosphere through the pressurization hole. A mass flow meter measures the gas flow through the pressurization hole to determine if it is capable of supporting requisite pressurization of a nuclear fuel rod when the end plug is assembled thereto.

Abstract: The testing device for measurement of a hydraulic leak rate of a spraying valve (11) with a closable outlet opening(11B) includes a vessel (10) filled with an indicating liquid (12) and a device for holding the valve to be tested with the outlet opening (11B) in an inclined position pointing downward into the indicating liquid during testing, a riser tube (14) formed as a glass capillary tube connected with the vessel (10), a balancing reservoir (17) also connectable with the vessel (10) but disconnectable from the vessel (10) with a shutoff valve (15), a light source (18) positioned relative to the riser tube (14) so as to illuminate the riser tube (14) and the liquid level (M) in the riser tube (14) and a linear scanning camera (19) positioned relative to the riser tube (14) so as to observe the height (H) of the liquid level (M) in the riser tube for accurate measurement of a change in the height (H) of the liquid level M when the closed valve is pressurized.

Abstract: The apparatus comprises an air flow duct having an end portion fitted inside a nozzle whose front surface is trued so that it can be applied against the surface to be scanned and so that it can co-operate therewith to form a leak through which air flows as a function of the surface state of the part, and further comprises measuring means for measuring the flow rate of air passing through the leak. At its trued front surface, the nozzle delimits an annular air flow duct, and the portion of the nozzle inside the annular air flow duct includes a duct connected to the atmosphere.

Abstract: A carbon sliding strip for a collector has a rupture control device, comprising a pressure line (9) incorporated directly in the carbon strip (1), a device (13) for producing increased pressure in the pressure line and a pressure detector (15), which detects the sudden drop in pressure which occurs if the channel begins to leak. Since at least part of pressure line wall is made directly from the carbon material, the pressure control device responds even to small cracks in the carbon and immediately shows wear and rupture.

Abstract: The fixed structure (10) incorporates an abutment surface (10a) upon which a corresponding abutment surface (8a) of the transportable element (1) comes to bear, with the interposition between the abutment surfaces (8a, 10a) of at least two concentric annular sealing joints (13a, 13b). The pressure in the space (18) between the sealing joints (13a, 13b) and bounded by the abutment surfaces (8a, 10a) is measured during the emplacement of the transportable element (1) to determine whether it is leakproof. The measured maximum pressure and/or the variation of pressure measured over time is compared with predetermined values corresponding to a correct emplacement of the transportable element (1).

Abstract: An accelerated wear and fatigue tester for replacement human heart valves includes a fluid which is caused to pulse the heart valve by a pressure generator utilizing a coil secured to a flexible diaphragm in contact with the fluid. The coil is subjected to a magnetic field and a signal selected from pulsed, sinusoidal, or random pulses and/or a DC offset, or a recorded signal from a human heart, such that the magnetic interaction selectively pulses the diaphragm and replacement heart valve to simulate heart action. A plurality of pressure generators with differing signals, including phase differences, may be provided to simulate arrhythmia in a heartbeat, and a library of recordings may be used as a database to predict irregularities in replacement heart valves.

Abstract: Current state-of-the-art requires welded seams between adjacent sheets of material, e.g. polyethylene to be tested for leaks using vacuum, ultrasonic or low pressure air techniques. In general, the devices used are somewhat complicated and consequently expensive. A relatively simple method of determining the strength and integrity of a welded seam between layers of plastic, which are interconnected by welding to form a sealed passage including the step of injecting air or another gas into the passage under sufficient pressure that any weakness in the seam results in a visible distortion or total separation of the plastic in the area of such weakness.

Abstract: A test fixture for testing a specimen under compressive or tensile load under close, reproducible tolerances and conditions. Confronting platens having surfaces which act against the specimen are provided with an in-line wedge assembly which drives the platens to load the specimen. The platens and wedge assembly are positioned between the top and base of a frame assembly. The top and base are connected by side plate members which are tensioned when the wedge assembly is operated to load the specimen via the platens. The test fixture also has a load cell in line with the platens and which is acted against by the platens to continuously sense the load applied to the specimen.

Abstract: A smoking machine includes, for controlling the conditions in which each article to be smoked is smoked, only a servo-control device for controlling, to a reference value, the pressure difference between the suction end and the rest of the body of the cigarette. The support of each article is mounted for rotating so as to allow, for example, more accurate detection of the position of the incandescent zone by optical sensors and a processing circuit.

Abstract: First and second thresholds are established which define a pressure difference relative to a maximum pressure level for a fluid under pressure, which maximum pressure level is detected by a pressure detecting device, and a third threshold is also established which is lower than the maximum pressure level and higher than the first and second thresholds. While a pressure detected by the pressure detecting device ranges between the first and second thresholds, an output signal is supplied to a drive member. When a pressure lower than the third threshold is detected by the pressure detecting device, an output signal indicative of a predicted failure is produced. The output signal indicative of a predicted failure is produced when a pressure lower than the third threshold is detected a plurality of times by the pressure detecting device.

Abstract: A method is described in which the operative condition of the cooling sections of a slot die for making flat films of thermoplastic material, or of an annular die of a blow molding extruder for making tubular films from synthetic thermoplastics, is tested. The cooling sections are provided with lines for supplying and discharging cooling air and the lines for supplying cooling air are connected, as required, to a central cooling air feed line, which is under superatmospheric pressure, by solenoid valves controlled by an electronic computer. In one embodiment of the invention, a testing program is performed in which the cooling air feed line is disconnected by a shut-off valve from the branch lines leading to respective solenoid valves when the latter are closed.

Abstract: A technique for detecting faults, blockages or holes, in a duct (6). A burst of compressed gas is injected into the duct and the decay of the pressure pulse monitored by a transducer at the gas burst launch end of the duct. A reference decay pressure that would be expected for a perfect duct is generated and the monitored decay is compared with the reference decay for deviation. A perforated duct exhibits greater pressure decay and a blocked duct less pressure decay than a perfect duct. The time occurrence of the deviation indicates the location of the fault. The signal level indicative of the pressure after a predetermined interval may also be used to measure the air friction or blowability within the duct.

Abstract: A method and device for testing the burst pressure of closure disks which provides high pressure to both sides of a disk and rapidly releases pressure from one side thereof causing a high rate of change of pressure. A hollow notched plug allows the rapid release of pressure upon rupturing. A tensile load is transmitted by a piston in combination with fluid pressure to the hollow notched plug.

Abstract: The bonding of a honeycomb structure to a support at one end of the cells of the structure is checked by applying a detector to the opposite end of the cells, the detector comprising first and second compartments which are separated by a partition, supplying compressed air to the first compartment, and measuring the flow of air out of the second compartment by means of a flowmeter connected to an outlet from the second compartment. The flow value measured by the flowmeter enables one to determine whether or not there are any non-bonded areas between the honeycomb structure and the support in the region of the detector.

Abstract: A gas comparison pycnometer is disclosed which provides a method and apparatus for determining and checking the accuracy of the volume of a solid substance. The pycnometer is also outfitted with a unique cap assembly which fixes the volume in the pycnometer's sample chamber from run to run. The pycnometer also employs a series of purges with a suitable gas to carry unwanted moisture and vapors out of the system. This pycnometer solves many problems in the prior art by quickly and accurately determining the volume of a solid substance.

Abstract: A fluid injection method of nondestructive testing for bonding between two layers of material, at least one of which is penetrable is presented. One or two fluid injection members are inserted at selected locations along the penetrable material to the bond line between the materials. In the single injection member test, a fluid under known pressure is injected through the injection member to the bond line. The flow is measured at several locations and an average flow rate under satisfactory bonding conditions is noted. Any flow rates in excess of some fixed amount above this established norm is considered unsatisfactory. In the two injection member test. The two members are adjacently inserted through the material to the bond line and a fluid under known pressure is injected from one injection member to the bond line. If a disbond exists between the two members, the second member receives fluid from the first at the bond line.

Abstract: Method and apparatus for generating a precisely defined dynamic pressure pulse. A rigid pressure chamber contains a pressure transmission agent. The pressure chamber has a through opening in which is disposed a piston. A drop weight outside the pressure chamber coacts with the piston to generate a pressure pulse. The mass of the drop weight and the cross section of the piston, along with the chronological curve of acceleration of the drop weight during coaction with the piston, are used to generate a curve representing the pressure pulse. The curve satisfies the following equation: ##EQU1## wherein: m=mass of the drop weight;a(t)=said acceleration curve; andA=said cross sectional area of said piston.

Abstract: A materials testing machine for testing equipment used for lifting or jacking up of objects. The machine has a frame with a generally horizontal arm extending outwardly therefrom. A hydraulic cylinder assembly is positioned along the horizontal arm and is connected to a pressure gauge. Lifting equipment may be connected between the frame of the machine and the end of the horizontal arm, and the amount of pressure exerted by the lifting equipment may be tested and the results read on the gauge thereof. A second hydraulic cylinder may be positioned over the platform so that a lifting jack may be similarly tested.

Abstract: Apparatus for testing a solenoid-actuated, hydraulic valve under actual operating conditions in a closed hydraulic system includes two pressure gauges to monitor valve switching pressure as well as electrical control switches and a test lead to power the valve. A closed hydraulic system includes a reservoir, a pump and a needle valve for controlling pressure. With the hydraulic valve de-energized, flow of the hydraulic fluid is in a first direction, with a first pressure gauge indicating the internal hydraulic pressure and a second hydraulic gauge indicating zero pressure. When the valve is energized, fluid flow direction is reversed in the system and the second hydraulic gauge now measures a pressure, with the first hydraulic gauge indicating zero pressure. Operation of the electrically actuated hydraulic valve can be tested under actual operating conditions prior to installation in a hydraulic control system.

Abstract: In a process for testing the tightness of a flexible collapsible container which in condition of use is sealed by means of a screw cap screwed on a spout, the container is evacuated after its manufacture, tightly sealed and subsequently subjected to atmospheric pressure. If the container is tight, it will remain its shape caused by the vacuum. The device for the application of this process consists essentially of a suction bell on which the container is placed and features a rotor unit with the aid of which a cap can be screwed on the container. The invention enables as such a simple and dependable testing of collapsible plastic containers, but also of containers of stable form as well as closures, specifically screw caps.

Abstract: A method and apparatus for determining the environmental stress crack resistance of plastic articles, such as polyethylene terephthalate containers, are provided. In accordance with the method of the invention, the internal chamber of a hollow plastic article is pressurized, the exterior of the base is then exposed to an environmental stress cracking agent, and it is then determined if crazing and/or changes in the base clearance of the plastic article have occurred. Subsequent increases in pressure and subsequent exposures and determinations yield information on the environmental stress cracking characteristics of the container.

Abstract: The method for measuring the elasticity of a superficial layer (2), in particular of the skin, comprises defining a zone (7) of this layer; creating a negative pressure in this zone to cause a deformation of the zone; and measuring the negative pressure necessary to cause a deformation of predetermined amplitude. The measuring device includes a sensor (3) provided with a cavity (5) defined by a rim (6) arranged to be pressed against the layer (2) to be studied, and a pump (17) for creating a negative pressure in the cavity (5). A suction opening (20) is provided in the cavity at a predetermined distance (d) from the superficial layer, in such a manner as to be obturated by the layer when the deformation attains the predetermined amplitude. A pick-up device is provided for measuring the negative pressure that has produced the deformation of predetermined amplitude.

Abstract: The invention is based on the realization that for a rod-like article, a cigarette for example, having a plurality of ventilation gas flows, the flows can be equated to a single equivalent flow nominally occurring at an "equivalent ventilation point". By establishing one or more flow regimes in a rod-like article and measuring gas pressures, the articles can be monitored for displacement of the equivalent ventilation point, such displacement being indicative of the position of out-of-specification gas flows.

Abstract: A pneumatic sensing device is presented which automatically senses the motion of a ball falling into a can. A sensing arm protrudes into the pathway of the dropping ball. When the ball hits one end of the arm, the other end of the arm rotates upward and closes off an exhaust port, creating a back pressure in a proximity switch. The proximity switch then sends a pneumatic signal to a four-way valve that allows the now filled can to move on to the next work station. Also presented is a method of using the sensing arm which uses a regulator and indicator to display when the ball drop station has been energized but the ball has failed to drop.

Abstract: A method of testing a dilatation balloon catheter prior to use which comprises purging and priming the balloon catheter with a balloon protector in place about the balloon.

Abstract: The invention discloses a method and an apparatus for explosion protection of plants, pipelines and the like by monitoring chronologically successive values of the system pressure in the potentially explosive area and by comparing these values with a predetermined pressure threshold, where the exceeding of this pressure threshold is used as a triggering criterion for initiating explosion protection provisions. According to the invention, instead of predetermining a constant value as the pressure threshold, the pressure threshold is updated continuously in accordance with the system pressure prevailing at that time. As a result, the pressure threshold can be set with a smaller safety margin above the system pressure than before. Brightness and temperature thresholds may also be used singly, or together with pressure in any combination in continuous value monitoring.

Abstract: A leak detector including a fill cylinder and a pressure cylinder mounted in spaced relationship on a frame. The fill cylinder includes a movable liquid-tight piston, valved ports on one side of the piston, and a vent port on the opposite side. The pressure cylinder includes a movable pressure piston, a pressure regulator in communication with one side of the piston, and an access port on the opposite side. A connecting rod interconnects the liquid-tight piston and the pressure piston and spans the space between the cylinders. A pointer attached to the connecting rod registers with a calibrated scale on the frame and movement of the pointer toward the fill cylinder indicates a leak in the pressurized liquid piping system being tested.

Abstract: A device for testing a package having, a device for passing a fluid inside the package, and a device for selectively controlling the rate of pressure increase inside the package by the passing device.

Abstract: Apparatus for applying a fluctuating stress to, for example, a gable end of a house includes a pressure enclosure. An air compressor is connected to the pressure enclosure via a series of gauged valves whose positions are continuously variable between limiting positions where the air compressor supplies all its output to, or takes all its output from the pressure enclosure. The effects of gusty winds can thus be simulated.

Abstract: A method for testing an hydraulic device of an hydraulic control system, the system having a source of hydraulic fluid under pressure and a fluid reservoir, and the device having a fluid inlet which is releasably coupled to the source when the system is in operation, a fluid outlet which is releasably coupled to the reservoir when the system is in operation, and an element which restricts fluid flow between the inlet and the outlet, by: halting operation of the system; providing a portable analyzing apparatus having a supply of hydraulic fluid, an outlet conduit, a unit for supplying hydraulic fluid under pressure from the supply to the outlet conduit, a return conduit communicating with the supply, a fluid pressure monitor connected to the outlet conduit, and a fluid flow monitor in the return conduit; disconnecting the fluid inlet of the device from the source and connecting that fluid inlet to the outlet conduit; disconnecting the fluid outlet of the device from the reservoir and connecting that fluid outl

Abstract: A method and system for testing safety relief valves utilizes a reservoir of high pressure fluid which is metered into a smaller pressure vessel in communication with the safety relief valve to be tested. The method and system permits a safety relief valve to be tested with air as well as water.

Abstract: A volume measuring apparatus comprises pair of tanks of substantially the same volume for supplying gas to a container to be measured and a refernce container, a pressurized gas source for filling the pair of tanks with gas under the same pressure, a volume adder for providing a known volume variation to either one of the container to be measured and the reference container, and a differential pressure detector for measuring the differential pressure between the container to be measured and the reference container. The ratio of the differential pressure variation to the volume variation, which represents the sensitivity for detecting differential pressure, is precalculated based on differential pressure variations obtained in the cases where the volume variation is provided and is not provided.

Abstract: Prior to pressurizing a garment at an opening therein, interior and exter elements are drawn together along the longitudinal axis of a tube through which the pressurizing gas is applied, to grip the garment around the full periphery of that opening. In one particular embodiment, a means for monitoring pressure within the garment is included in the apparatus to provide for leak testing the garment after it is pressurized.

Abstract: The apparatus and method for the field measurement of bearing lubricant involves obtaining a control pressure value which is indicative of the pressure which would be generated by injecting a known, controlled volume of air or gas into a test bearing at the existing ambient temperature and pressure. Then, the same controlled volume of air or gas is injected through a valve controlled opening in the test bearing housing by an injection fixture which is sealed to the housing and which is connected to an injector for such controlled volume. Once the controlled volume is injected, the actual pressure in the test bearing is sensed and compared with the control pressure.

Abstract: The proposed technique makes use of a non-deformable sealed tank (10) of specific volume, a pressurized-fluid supply (30) equipped with a connector (31) intended to be connected to an orifice in the hollow component (50), a liquid delivery (20) for filling and emptying the tank, once the component has been submerged in it, and a sensor (40) for detecting the variation in volume of the liquid in the tank resulting from the deformations of the casing of the component which are caused by the set pressure of the fluid prevailing in it. The invention is used to assess the probable emission capacity of components during their design, in particular intake-line of motor-vehicle engines.

Abstract: A pressure vessel comprises a cylindrical container with a closed end, externally threaded at an open end, and having an O-ring seal in the end surface of the container side wall. A cylindrical disk closes the open end of the container and has a raised neck portion surrounded by a recessed cavity having a rupture disk therein. An internally threaded cap memeber has a hole through its end wall through which the raised neck extends and forms an annular passageway therebetween, and has an enlarged diameter on its side wall above the threaded portion to provide an annular passageway surrounding the disk circumference. The cap is screwed on the container over the cylindrical disk with the disk neck portion extending through the hole in the cap, and when hand tightened thereon compresses the disk on the O-ring to seal the container and isolate the threaded cap connection. The raised neck has an internally threaded bore and a valve seating surface for connecting the container with pressurizing apparatus.

Abstract: Apparatus utilizing pressurized liquid for testing containers such as soft drink beverage bottles for the ability to withstand internal pressure and for the absence of leakage. The pressurized liquid is introduced into each bottle with a swirling motion through an annular passageway and air is expelled from the bottle through a vent tube positioned coaxially within the passageway. The outer wall of the annular passageway is formed by a resilient sleeve which is compressed radially and extended axially by the pressurized liquid to provide a tight seal with the bottle. Pressure within the bottle is monitored by a sensing member which is displaced by the pressurized liquid and actuates a pivotally mounted lever arm which provides an amplified movement and corresponding to the displacement of the sensing member.

Abstract: Apparatus for sensing the condition of a slurry transport line in a wet blasting apparatus. Slurry transportation lines feed the blasting guns of a wet blasting machine. The blasting guns are carried by a gun supporting member by means of interposed resilient members for isolating each gun from the vibration of adjacent guns. A vibration sensor fixed on the nozzle of each gun provides an electric output signal to a measuring device related to the amount of vibration of the gun on which said sensor is mounted.

Abstract: A method for the rapid acoustic emission testing of pressure vessels wherein the flow rate of the pressurizing fluid is increased while maintaining the velocity of the pressurizing fluid, as it enters the pressure vessel, below the velocity which would cause the generation of flow noise.

Abstract: A machine for reprocessing catheters of the type having a double lumen, one of which leads to a balloon. A used catheter is sealed within a cassette which in turn is connected by multiple ports to a cleaning side of the machine. Cleaning solution is flushed through the inside and outside of the catheter. The balloon integrity is tested by adding step wise volume additions and monitoring the pressure. The data generated is compared to a standard curve for new catheters. The cleaned, sterile catheter is then rinsed to remove all traces of sterilant. Sterile saline is alternatively flushed through the cassette and catheter. The balloon is again tested for leaks. No portion of the rinse side of the machine requires sterilizing except for the disposable tubing set and saline source. The rinsed, clean and sterile catheter is removed from the cassette for reuse.

Abstract: A device for testing containers as to leakage and defects is comprised of a container sealing portion (4), a pressure exerting portion, and a pressure gauge (8). Said pressure exerting portion is provided in the shape of a piston/cylinder system (2, 3) that is maintained in an extended position by a tensioning means, e.g. a spring (5). Said container sealing portion (4) is provided either on the piston (2) or on the cylinder (3) for sealing contact with the container opening. The chamber between the cylinder (3) and the piston (2) is in communication with the pressure gauge (8) and, via a channel (13) in the container sealing portion (4), with the interior of the container (1). The device may, furthermore, be provided with a feeler means (12-19) for testing the container as to moulding films and the like.

Abstract: A method of and a device for sensing the presence or absence of an electrical or electronic component at the end of a vacuum pick-up means. In the absence of a component, the air flow produced by the vacuum is converted into an acoustic signal which indicates the absence of the component.

Abstract: An apparatus and method for testing prosthetic heart valves prior to implant in the human body provides a test chamber having a flow channel therethrough and a passageway which receives a mounting fixture for a heart valve. The test chamber is used in a mock circulatory loop with the flow channel being in the loop. Preferably, the test chamber has a transverse passageway that intersects the flow channel, and the mounting fixture advances completely through the test chamber from an insertion location to a disconnect location while a dynamic seal is maintained. Two such test chambers may be used in a mock loop, and the loop is configured with an intake chamber fluidly interconnecting one side of each test chamber, and a restriction chamber fluidly interconnecting the other sides of the test chambers. The restriction chamber is variable, and pressure compensation is provided between each of test chambers and the restriction chamber.

Abstract: A dispenser for fluid under pressure has a sensor affixed to it to sense the pressure of the fluid proximate the dispenser discharge opening to generate a pressure reflective signal. A comparator is connected to receive the pressure reflective signal to compare the pressure signal with a preselected band of pressure values which are selected to reflect operating pressures when the dispenser discharge opening is opened. The comparator generates a malfunction signal when the sensed pressure signal is outside the preselected band.

Abstract: A method for determining the closing point of a pump piston relative to a transverse bore in a corresponding pump cylinder, the method including the steps of providing compressed air to the cylinder via the transverse bore, axially sliding the pump piston near the closing point, consecutively measuring two flow values through a throttle cross-section defined by the pump piston and transverse bore, measuring the positions of the piston corresponding to the two flow values and extrapolating the pump piston unto the closing point from the flow values and piston positions.

Abstract: An improved back-pressured pneumatic pressure cell is provided along with a method of using the same. The device includes at least one sensing cell mounted on a blade for insertion into the soil. The cell includes a perforated outer ring and a perforated central disk separated by a threshold. A resilient membrane covers the outer ring and central disk. A first back-pressure is applied through the perforations of the outer ring to the membrane, while a second back-pressure is applied through the perforations of the central disk to the membrane. The second pressure is slightly less than the first pressure. When the first pressure reaches the soil pressure, the seal between the membrane and the threshold is broken, thereby permitting a momentary reverse flow of pressure through the perforations of the central disk until the first and second pressures equalize, as monitored by a differential pressure gauge. A valve regulates the pressure differential between the first and second pressures.

Abstract: A test system for air data sensors includes means for mounting the system components directly on the sensor and provides a self contained source of the necessary vacuum or positive pressure as needed for testing the sensor for function. The self contained test system includes manual pressure creating means that is self limiting to prevent excessive pressures being generated. In one form of the invention the entire assembly slips over and is supported on a sensor probe, and includes passageways and connections to provide the fluid pressures required to the sensing ports. In a second form, the self contained test system mounts on the sensor strut and has a pressure fitting that fits over the ends of a probe barrel to provide an adjacent coupling means for supplying the fluid pressures to the respective ports. The test system is a compact, easily mounted unit that is supported directly on the air data sensor being tested, and which has self contained fluid pressure sources for the necessary test.

Abstract: Hydrostatic test apparatus for pressure testing fire hoses, pressure vessels such as fire extinguishers, or the like, including a small, portable unit having an inlet line for connection to a hose from an ordinary water tap, for example, an outlet line connected to the item to be tested, a pump, a first bypass line between the inlet lines for filling the item being tested, a control valve in the first bypass line which is closed during testing to prevent backflow of test pressure into the water supply, a pressure gauge in the outlet line for reading test pressure, and an adjustable relief valve in a second bypass line between the inlet and outlet lines for setting a predetermined test pressure. Air vents or bleeds allow the apparatus to be completely bled of air before testing to assure accuracy of the test pressure readings. The apparatus operates on very low water volume for safety.

Abstract: A portable instrument system is provided for the testing of pressure and flow characteristics of implantable ventricular shunt valves using a gaseous testing fluid that may be drawn from the testing environment. The system includes a rate pump having a control mechanism that provides a variety of selective constant flow rates so that the valve characteristics can be determined under various operating conditions. Fluid communication is provided between the pump, the valve and a pressure sensing device such that the pressure sensing device receives the same pressure and flow rate that the valve does. Typically, the pressure sensing device is a gauge transducer that utilizes atmospheric pressure as a reference point and senses the changes in the gas pressure in the valve, relaying the pressure readings to a digital display or chart recorder.

Abstract: Pressure vessels are tested for structural integrity by recording acoustic events generated in the vessel's walls while it is immersed in water and subjected to internal pressure above the vessel's working pressure. Acoustic events are recorded by sensors fixed either to the wall of the vessel or to the walls of the water container in which the test is conducted. In preferred form, the vessel is water filled throughout the test and its volumetric increase with pressure is measured in an initial over-pressurization.