A method and apparatus for quickly determining leakage in pressurized fluid receptors. Pressure determinations are made substantially immediately following the completion of the filling of the item to be tested with the pressurized fluid without the need for a stabilization period. The complete decay curve is calculated from the pressure determinations. A time constant is determined from the curves defined when no leakage is present and is utilized in determining the leakage rate whenever the two curves defined by the pressure points provide different end pressure values. The determinations may be made by conventional microprocessor-based instrumentation to provide a substantial increase in the rate of conducting fluid leakage tests.
A method and apparatus for testing a fluid conduit system for leaks. The apparatus is connected to an isolated section of a domestic fuel gas system which is suspected of leaking. The apparatus determines over recorded time periods the pressure drop in the system as a result of the actual gas leak and subsequently the pressure drop in the system as a result of an actual leak plus the leakage through an introduced artificial and calibrated orifice provided by the apparatus. The data is used in an equation for calculating the actual leakage rate from the system. This method avoids the need to repressurize the system between pressure drop measurements or having to know or assume the volume of the system being tested.
A process control system is disclosed in which process variables are treated as mapped in n-dimensional space, where n is the number of orthogonal directions. Three functions, set, check, and term, provide the link between expected and actual conditions. The check and term functions operate on orthogonal coordinates. Each parameter has a guard band to provide a soft boundary for the parameter.
Risk of hydrodynamic pressure noise interference with a valve leakage test conducted upon a plurality of valves within a pump assembly is minimized. A pressure sensor within the pump assembly produces a signal indicative of hydrodynamic pressure in fluid distal of an outlet valve of the pump. The signal produced by the pressure sensor is input to a microcontroller that controls the pump assembly. Prior to conducting the valve leakage test, the hydrodynamic pressure level of the fluid is sampled at a frequency that is at least twice that of the hydrodynamic noise. The microcontroller determines if a maximum of the samples of the hydrodynamic pressure level taken during a data interval is above a predetermined threshold. If so, the valve leakage test is suppressed until the maximum pressure level is below the predetermined threshold during a successive data interval. If the hydrodynamic pressure noise level fails to fall below the predetermined threshold within several data intervals, an alarm alerts an operator of a noise fault condition.
The apparatus for checking the volume of bottles (1) comprises a head (2) adapted to be moved sealingly onto the bottle mouth (21), with a metering piston (7) which is displaceable in relation to the head (2) to be inserted into the bottle (1) and compress the air contained therein, and a pressure sensor (9) for measuring the excess pressure produced in the bottle. The measured volume (11) in the bottle is linked to a compensating volume (12) through a duct (10). The compensating volume is determined on the one hand by the constant starting height of the metering piston (7) and on the other hand by the variable displacement path length of the head (2). This ensures that the compression ratios are always the same for bottles of different heights, since differences of bottle height are compensated by a balancing piston (13) in the opposite direction, which alters the compensating volume (12) according to the sealing displacement path of the head (2) and thus always keeps the compressed measured volume exactly constant. The apparatus enables deviations in volume occurring in a series production process for plastic or glass bottles to be determined without the need to supply external air to the bottles. The measuring cycle is initiated by recording the pressure rise when the head (2) is placed upon the container (1).
A pressure transducer, a microprocessor, and associated electronics are enclosed in a probe housing which may be attached to a liquid conduit with the pressure transducer responsive to the pressure of the liquid in the conduit to provide an electrical signal representative of the pressure. A temperature sensor is mounted in a cavity in the base of the housing to provide an electrical signal representative of the temperature of the liquid in the conduit. Decision criteria related to conditions of the liquid storage and dispensing system to which the probe is attached are stored in the microprocessor memory. The microprocessor logic processes the electrical signals using the stored decision criteria and provides a signal indicative of conditions in the storage and dispensing system. The probe automatically disregards temporary pressure drops due to harmless common procedures, disregards or compensates for pressure drops due to changes in temperature, and permits the pump serving the conduit to be temporarily turned on to test for leaks after repairs but prevents the pump from being activated for significant periods when leaks are present.
