Abstract: A liquid leak detector for above-ground tanks includes an upright standpipe connected to the tank so that the standpipe can be filled with liquid from the tank to the same level as the liquid in the tank. A pressure transducer is connected between the bottom of the tank and the bottom of the standpipe to measure the difference in pressure of the liquids in the tanks and standpipe. Any change in the liquid pressure at the bottom of the tank as a result of leakage from the tank will change the pressure differential on the pressure transducer. This changes the output of the transducer which can be recorded to indicate leakage from the tank.

Abstract: A system for detecting leaks in hazardous liquid tanks, particularly underground gasoline tanks at service stations. The tank is filled incompletely to leave a space in the tank which is then filled with a gas under pressure. A reference tank is disposed within this space and continuous streams of gas are forced into the liquid in the reference tank and the liquid in the tank being measured. Resistance to gas introduction in the reference tank is compared with the resistance to gas introduction in the gasoline tank and monitored during a test period to note any differential variation which would indicate a leak in the tank.

Abstract: A pressure difference type liquid level meter for measuring the quantity of an object liquid includes a liquid receptacle containing the object liquid, a pressure transmitting device including a pressure transmitting liquid for transmitting a pressure from the object liquid to a pressure difference detector so as to compare the transmitted pressure with a reference pressure, and an isothermal device for maintaining at least part of the pressure transmitting liquid at a predetermined temperature.

Abstract: A leak detection system for detecting the leakage of fluids from storage tanks uses a reference container, such as a standpipe, having its bottom adjacent the level of the bottom of the tank, which is initialized to the same hydrostatic head pressure as the tank, and then closed off. The differential pressure between the hydrostatic head pressures of the standpipe and the tank is monitored over time in an externally mounted differential pressure gauge in order to detect the leakage of fluid from the storage tank. Shut off of valves are provided in a tank pressure pipe and a reference pressure pipe to isolate both sides of the differential pressure gauge. The very high sensitivity of available differential pressure gauges allows the detection of very small leaks and very low leakage rates. A leak detection system of unitary construction may be provided in which the standpipe is provided with an equalizing valve so that the system may be installed through a single hole in the top of a liquid storage tank.

Abstract: A liquid leakage detection system for use in underground storage tanks includes at least two vertically-disposed tubular members mounted to be partially immersed in liquid in the tank. A valve selectively opens and closes the lower end of at least one of the tubular members and air-bleed valves are connected to the upper ends of at least two other of the tubular members. With the air-bleed valves closed, a differential pressure transducer is connected to sense the gas pressure in the tubular members. A control system selectively operates the valves so that the pressure transducer indicates changes in liquid levels within the tank caused by leakage.

Abstract: A method for measuring the filling level of a liquid in a pressure vessel of a boiling-water reactor, includes measuring the pressure difference between a lower subspace and a reference column, determining steam density in an upper subspace from the measured pressure, determining liquid density in the lower subspace, determining the liquid density in the column, subsequently determining the level in the vessel from the liquid densities in the lower subspace and column, from the steam density in the upper subspace and from the pressure difference and from taking into account time-dependent transient alterations of the values of the densities by measuring the pressure change over time in the upper subspace, the power output and the temperature of the liquid in the vessel, determining therefrom the liquid density in the lower subspace and the steam density in the upper subspace with the measured pressure in the steam space and with known dimensions and quantities, and measuring ambient temperature in the vicinit

Abstract: The present invention provides for a process and apparatus for detecting the level of a liquid in a vessel. The method involves sensing the pressure head of the liquid level in column disposed with the vessel wherein the column liquid level has been adjusted to a first predetermined level. The level in the column is then adjusted to a second predetermined level. The pressure head of the second predetermined level in the column then sensed. The pressure of the liquid head in the vessel outside the column is sensed. The three pressure values are then used to determine the liquid level in the vessel.

Abstract: A system for detecting leaks over a designated test period in liquid storage tanks and like systems having underground tanks which are connected with good withdrawal systems. A fill pipe provides for obtaining a differential pressure measurement reflecting a difference in head of adjacent columns of liquid in the tank. One of the heads is stabilized at the beginning of the test, and prevented from changing as a result of any loss of liquid due to leak over the test period, while the other head is permitted to change with a lowering of surface level due to leaks. Both heads respond in the same way to a change in temperature which occurs during the test period. The differential pressure is monitored and any variation over the test time period is indicated.

Abstract: A tank contents gauge is disclosed having two pressure sensors to sense the liquid pressure at two tank positions at known vertical separation, a port to sense the ambient pressure in the tank, and a transducer to which the three pressure readings are transmitted one at a time by a switching mechanism. If the transducer is a differential transducer, its second side is connected to the port to allow (1) comparison of the pressure readings with the ambient pressure reading and (2) determination of transducer offset to adjust the calculations to give accurate readings. The readings are analysed by a data processing system which can provide volume and weight readings by internal look-up calibration tables. The system may also control the switching mechanism. Specific gravity values can be calculated from the pressure readings and the known vertical separation; the values can be stored in the system for use when the tank contents approaches, or falls below, the level of the upper sensor.

Abstract: A tube vertically disposed in a liquid storage tank, in which the tube has a cross-sectional area which changes with height in proportion to the variation in the tank's cross-sectional area. The tube is filled through an open valve near the bottom of the tube and the valve is closed for the remainder of the test. Other valves above the liquid level are kept open to maintain equal vapor pressures in the tank and the tube. A first sensor measures the fluid level in the tank, while a second sensor measures the differences in fluid levels between tank and tube over a period of time. Ambient height changes are identical for liquid in both tank and tube, whereas leak related height changes occur only in the tank. A second identical tube may be provided when levels are affected by the tube or sensor, or when the tube is required to hold the sensor and is open to the tank.

Abstract: This invention relates to apparatus for determining the amount of liquid in a tank by measuring the pressure at the bottom and at a height above the bottom of the tank, and provides apparatus for compensating for apparent volume measurement variations caused by expansion and contraction of the tank and liquid with variation in temperature. A tube which expands in length at an exactly compensating rate varies the height of the second pressure sensor relative to the first. A further embodiment is a pneumatic system which avoids the necessity to immerse the pressure sensor, and utilizes an inexpensive single differential pressure transducer instead of two, and which cancels out the effect of any changes in zero setting of the transducer, changes in sensitivity of the transducer, or changes in atmospheric pressure.

Abstract: A high-accuracy system for gaging liquid height in storage tanks. A pair of standpipes are arranged to be pumped to several accurately predetermined liquid levels to enable zero and sensitivity calibration of a differential-pressure transducer which normally monitors the pressure head of a column of liquid in the tank. The entire system is filled with tank liquid (eliminating condensation and vapor bubble problems encountered if the transducer is vented to atmosphere), and sharp-edged standpipes provided to minimize meniscus error when one or both standpipes are completely full.

Abstract: A hydraulic liquid pressure sensor for use in a gas operated pressure sensor system includes a sensor body with a generally circular membrane resting surface, an inlet connected to a peripheral portion of the surface and an outlet opening from a central location on the surface. A flexible membrane is positioned adjacent to the resting surface and in flush contact therewith when not in use. The flexible membrane is secured and sealed around the periphery of the circular membrane resting surface. The inlet includes an annular groove in the pressure sensor body and spaced around substantially outward of the outlet opening. The inlet also includes an additional groove in the sensor body opening to the resting surface, connected to the annular inlet groove and extending inwardly therefrom.

Abstract: A device for automatically controlling the water level in a basin, such as a bathtub. Air pressure in a tube is used to halt water flow into the basin when a desired water level is reached. Various water levels can be selected by opening pressure relief openings in the tube.

Abstract: In combination with a blood reservoir, a blood volume detecting apparatus is used to ensure safe operation of the reservoir which includes a conduit in fluid communication with a lower part of said blood reservoir, a diaphragm associated with the other end of the conduit and movable by a differential hydraulic pressure applied by the blood through the conduit, and means for detecting the swelling and contracting movement of the diaphragm.

Abstract: The present invention relates to a device making it possible to detect variations in the height of the free level of a liquid in an enclosure.The device comprises a vertical short tube issuing into the upper part of the vessel and whose upper end issues into a first condensation pot, a long tube whose long end issues into the vessel at a level below that at the end of the short tube, the end of the long tube being provided with a hydraulic seal, while the upper end of the long tube issues into a second condensation pot, a differential manometer indicating any pressure differences between the two condensation pots.Application to the measurement of the level of the water contained in the vessel of a pressurized water nuclear reactor.

Abstract: The head for the hydrostatic detection of a liquid level includes a main enclosure which is divided by a membrane into two chambers, one of which communicates with a supply of air under pressure, while the other is joined to a probe that is immersed deeply into the liquid. That connection is made, in this case, by the intermediary of an auxiliary enclosure that also contains a primary chamber that communicates with the inlet of the air under pressure, and a secondary chamber which is separated from the primary chamber by a membrane. That membrane forms one piece with a valve mounted between the chamber and a small connecting conduit connected with a probe, which prevents any ill-timed rise of the liquid inside the device, in the case of the disappearance of the compressed-air supply, and which makes it possible, at the same time, to install the detector head above the tank.

Abstract: A device for determining the level of a liquid in a tank comprising a manually-operated spring-loaded piston in a piston chamber, wherein the chamber is connected to the tank and a gauge. Pressing the piston causes the gauge to reach the pressure at the bottom of the tank, which is calibrated to give the height or level of the liquid in the tank.

Abstract: A pressure level sensor for mounting a pressure transducer in a fluid flow channel. The sensor is characterized by an elongated wedge-shaped configuration wherein the width of the convex front wall portion is less than that of the rear wall portion which in turn is less than the length of the sensor. The side wall portions of the sensor each have concave surfaces, the radius of curvature of which is a function of the length of the sensor. At least one side wall portion contains a horizontal pressure port for communication with the pressure transducer. The front, rear, and side wall portions are tapered and curved vertically inwardly and terminate at a top wall portion. When the sensor is arranged on the bottom of the channel with the front wall portion facing upstream relative to the fluid flow, the velocity vector of the fluid flow is perpendicular to the direction of extension of the opening, thereby to minimize flow velocity effects on the pressure transducer.

Abstract: A fluid pressure sensing device for a fluid-containing vessel, and a method of assembling said device, is disclosed. A metallic diaphragm is preferably laser-fused to one end of the sensing device to define the end surface thereof. The sensing device is preferably mounted and sealed with the wall of the vessel such that the diaphragm and such sealing engagement is substantially flush or coplanar with the inside surface of the wall. A passageway extending through the sensing device admits an indicator fluid to one side of the diaphragm for measuring the pressure of the fluid in the vessel. The passageway also includes an adjustable nozzle for pre-calibrating the sensing device.

Abstract: An apparatus for measuring fluid pressures which comprises a gas-type pressure sensor and a sensor control for supplying controlled purge gas to the sensor and for receiving vent gas from the sensor. The apparatus further includes a unique pressure-reducing device operable in response to a differential gas pressure in the sensor control for creating a zone of pressure less than any other in the apparatus, which zone is placed in fluid communication with gas in the apparatus to reduce the overall pressure thereof. This permits the accurate measuring of pressure at or below atmospheric. An integral design and a retrofit design are disclosed.

Abstract: A fuel gauge for locomotives comprises a block adapted for attachment to the locomotive fuel tank near the bottom thereof, preferably by connection with a tank drain plug. First and second chambers in the block are joined by a passage connecting the lower ends thereof and serve as a reservoir for an indicator liquid having a density greater than that of the fuel to be gauged and being immiscible with respect thereto. Valve-controlled passage means connects the interior of the tank with the upper end of the first of said chambers, permitting fuel to enter the first chamber and form an interface with said indicator liquid. A gauge glass connected with the upper end of the second of said chambers in conjunction with a gauge scale provides a visual indication of the quantity of fuel in the tank.

Abstract: A system for measuring the level of liquid stored in deep tanks or vessels that allows the use of a lightweight, relatively non-toxic, non-corrosive gauge fluid of normal column height is disclosed. The system discloses a diaphragm manometer that alters a greater pressure from the tank liquid into a lesser pressure from the gauge fluid permitting such gauge fluid to be lightweight and making it unnecessary to use high density fluids which are usually toxic, contaminating and have other undesirable handling characteristics. The device can be used for open tanks, or, with adaptations, for sealed tanks. For open tanks, the device provides two sealed chambers having two opposing diaphragms. For sealed tanks, pressure neutralizing elements are added with one device providing three sealed chambers and two diaphragms with neutralizing connectors, and another providing three sealed chambers and three diaphragms.

Abstract: Disclosed is an apparatus which utilizes pipes of different lengths oriented vertically within the fluid of a reservoir which are constantly pressured with a gas source, normally air. Since the pipes are of different length, but the pressure is the same, a different back pressure will occur in the longer pipe as compared to the shorter pipe due to the differing head of fluid which must be displaced by the gas to slowly bubble out of the lower end of the pipes. This pressure differential is then read and the calculations applied, either from a table or constantly monitored through a computer, to measure the pressure differential and calculate the same in terms of specific gravity. Once the specific gravity is known, the back pressure on either the short pipe or the long pipe can be impairedly calibrated, or calculated by an equation having the specific gravity now known, and then determining from that the back pressure which will vary with the height of the fluid in the reservoir.

Abstract: A water level gauge for a nuclear reactor includes heat conduction means for absorbing and conducting heat to the outside of the drywell, the heat being supplied to reference water head water inside a reference water head tube defining a reference water level inside a reference water level container, and to water inside a lower part pressure pipe connecting a nuclear reactor pressure vessel with a differential pressure detector. The water level gauge further includes heat exchanger for removing the heat. With this device, the water level of the nuclear reactor may be correctly detected even in the case of leakage accident of the coolant of the nuclear reactor.

Abstract: According to a level meter of this invention, a pressure corresponding to a fixed water level formed by means of a reference chamber and a vertical pipe is applied to one pressure inlet port of a differential pressure detector, and a pressure corresponding to a water surface or water level inside a container to be measured is applied to the other pressure inlet port of the differential pressure detector by means of a lower pipe. Then, the water level inside the container is measured through the difference between these two pressures, the density of water to generate the pressures to be applied to the differential pressure detector, and the density of steam inside the container and the reference chamber. Adiabatic jackets are attached to the peripheries of the vertical pipe and the lower pipe.

Abstract: A manometer type instrument with an open leg above an indicator fluid. It is subject to immersion in a body of liquid, the change in level of which is to be measured. It includes an improvement which eliminates the formation of a capillary seal at the top of the open leg. The improvement uses a relatively thin wire that is supported so as to extend down into the open leg far enough to reach through the capillary seal.

Abstract: A liquid level system employs a pair of vertically spaced sensors in a tank such as a boiler. Each sensor includes a pair of bellows. The first bellows is enclosed by a protective enclosure while the second bellows is exposed to the interior of the tank. The first bellows of the two sensors are interconnected and filled with a liquid forming substance, such as an alkali metal, which is in liquid phase at high temperatures, while the second bellows of each sensor and the enclosure for the first bellows are interconnected and filled with a second liquid-forming substance, such as a metal alloy, which is essentially inert. A transducer is connected to one of the second bellows which produces an electrical output signal proportional to the difference between the pressures at the locations of the second bellows and, thus, the level of liquid in the tank.

Abstract: A sewer flow measurement system for determining flow conditions of a sewer line system wherein separately located monitors make and record precisely synchronized and time identified pressure measurements, utilizing pressure-to-signal transducers positioned on the bottom of pipes where they exit into manholes. A cassette recorder records the different pressure related signals from the monitors together with a discrete identification signal from each monitor. The outputs of the recorder are then fed to a pressure-to-flow computer which provides location identified, time synchronized, flow data for the system.

Abstract: A device for displaying the level of a fluid in a tank includes a housing, a membrane being positioned within the housing to separate the housing internally into a first portion and a second portion, which are fluid tight from one another. Fluid communication between the tank and the first portion of the housing is provided by conduit or the like. A pipe, at least a portion of which is transparent or translucent, is in fluid communication with the second part of the housing. A display liquid of given substantially fixed volume is held within the pipe. A spring within the second portion of the housing is in contact with the membrane on that side thereof which is in contact with the display liquid. A nut fixed to the housing has a screw extending through it into the second portion of the housing, the screw being in contact with the spring to adjustably compress it. Marks for determining the instant relative position of the screw with respect to the nut are provided on the nut.

Abstract: A liquid level system having a bellows biased with a spring having a constant to add a variable force to a water column of a magnitude substantially equal to a loss in pressure resulting from an increase in water temperature. Such a system may also have high and low pressure connections to corresponding bellows and springs. The reference column may also be large in comparison to the remainder of the capillaries.

Abstract: A method and means of determining inflow (undesired pipe drains to a sewer) and infiltration (sewer pipe leakage) into sewer lines by a coordinate measurement of pressure in sewer pipes at several locations, particularly measuring flow during rainfall and for a discrete period thereafter and comparing the results with dry periods.

Abstract: A device to measure both the fuel level in high wing aircraft fuel tanks and check for water and other impurities in the fuel tanks. This invention is used from the underside of the wing and is inserted from below into the fuel tank sump valve. The device measures both the height of the fuel within the tank to determine how full it is and at the same time drains fuel into the device for visual inspection of water and other impurities. The device can be used to determine both fuel level and impurities at the same time or separately.

Abstract: An indicator providing a visual indication of the level within a rinse aid dispenser tank for dishwashers, consisting of a U-tube containing an indicator liquid having one leg in communication with the lowermost region of the tank and with the other disposed adjacent a viewing window. Air pressure generated in the connecting tubing by the relative liquid level in the tank acts to control the position of the liquid in the U-tube to provide a level indication at the viewing window. The air column intermediate the tank and the U-tube section is vented each time the door is opened to avoid variations in indication occurring with temperature and atmospheric pressure changes. The indicator liquid is introduced through a fill and drain tube extending from the upper end of the leg into the dispenser tank, such that a calibrated volume of liquid is introduced by flow into the U-tube from the tank and drain back of the excess over the calibrated volume.

Abstract: A method and means of determining inflow (undesired pipe drains to a sewer) and infiltration (sewer pipe leakage) into sewer lines by a coordinate measurement of pressure in sewer pipes at several locations, particularly measuring flow during rainfall and for a discrete period thereafter and comparing the results with dry periods.

Abstract: A sensitive J-tube employs an indicating liquid in the U-tube portion for use with an immiscible liquid thereabove. The longer leg of the J-tube has a larger cross-section area portion containing the immiscible liquid when the J-tube has been immersed therein. The arrangement is such that the J-tube will amplify any changes in surface level of the liquid into which it is immersed, by producing a differential between levels of the indicating liquid in the U-tube legs.The principles are applied to a U-tube instrument to act as a manometer for measuring gas pressure differentials.

Abstract: A method and means of determining inflow (undesired pipe drains to a sewer) and infiltration (sewer pipe leakage) into sewer lines by a coordinate measurement of pressure in sewer pipes at several locations, particularly measuring flow during rainfall and for a discrete period thereafter and comparing the results with dry periods.

Abstract: A liquid level gauge for tanks and other liquid holding receptacles, having a pressure sensing chamber which is partially enclosed by a flexible diaphragm and which is communicated with a pressurized medium. Pressure control means cooperative with said chamber, is communicated therewith together with a switching means to neutralize the deflection of the diaphragm which is normally caused by liquid in the tank.

Abstract: A liquid level sensor for determining the fluid level in a container and for controlling a fluid inlet to the container in response to the fluid level therein. The sensor includes a buoyant liquid-filled flexible conduit or liquid-filled hinged pipe member in the container and a pressure transducer responsive to the head pressure of the liquid in the flexible conduit or hinged pipe member.

Abstract: Apparatus suitable for use as a hydrostatic pressure standard comprises a vertically-mounted container charged with a predetermined amount of a liquid having a low-vapor pressure, such as an hydraulic oil, to provide a predetermined pressure head at a port at the lower end of the container. The container is provided at its upper end with a closure in the form of a variable volume device which is so arranged that the pressure in the space within the container above the liquid is maintained substantially equal to the external, e.g. atmospheric pressure. A system for determining the mass of a liquid in a tank and embodying two such pressure standards is also described.

Abstract: A system for measuring the water level, within a predetermined range, at the bottom of a tank containing gasoline. A first air bell is adapted to be inserted into said tank and has an opening in the lower part thereof to define a first interface. A second air bell is disposed interiorly of the first air bell and has an opening in the lower part thereof to define a second interface which is lower than the first interface. The upper ends of the air bells are in communication, respectively, with opposite legs of a manometer so as to produce a displacement of manometer liquid as a function of the difference of hydrostatic pressure between said interfaces whereby said displacement is a function of the water level therebetween, there being minimum displacement when the water level is at said second interface and maximum displacement when the water level is at said first interface.

Abstract: A method and means of determining inflow (undesired pipe drains to a sewer) and infiltration (sewer pipe leakage) into sewer lines by a coordinate measurement of pressure in sewer pipes at several locations, particularly measuring flow during rainfall and for a discrete period thereafter and comparing the results with dry periods.

Abstract: A petrol gauge for motorcycle is disclosed making use of the pressure existing at the bottom portion of the petrol tank. It comprises a display needle, the position of which depends on the position of a diaphragm of a pressure gauge device connectable with the tank, said pressure gauge device being made of a chamber scaled off by the diaphragm and by a removable plug at the bottom of the chamber, means being provided for preliminary calibration both at full and empty load of the tank.

Abstract: A sensor apparatus for determining fluid levels and pressures in a fluid-containing vessel wherein the sensor apparatus comprises a mounting member having a fluid passageway positioned therein; a pressure sensor in operative contact with one end of the mounting member and a pressure fluctuation dampening device operatively positioned on the other end of the mounting member. The dampening device comprises an arrangement of fluid passageways arranged so that the fluid passageway through the mounting member substantially perpendicularly intersects a second fluid passageway intermediate the ends of the second fluid passageway with the second fluid passageway being intersected at each of its ends by third and fourth fluid passageways.

Abstract: Liquid level in a vessel of cryogenic liquid or solid-liquid slurry is determined and indicated by sensing, in an immersed tubular probe, a probe-evoked vapor gas pressure counter balancing the hydrostatic head to the probe tip, and displaying an output on an appropriate meter scale or by a digital readout device in level height or other vessel-content terms, and, if desired, activating a low level alarm; the probe as a heat pipe conducting heat, from a source external of the liquid, to the probe bore as far as the tip to volatilize liquid entering the probe tip from which as a sensing gas the gas phase may slowly bubble; a differential pressure sensing device being connected to the probe and to the vessel gas space for a closed vessel.

Abstract: A liquid level transmitter in which the level of liquid in a tank is detected by a sensor formed by a housing attached to the tank over an opening therein, the housing having a fill chamber defined by a sensing diaphragm which is exposed to the liquid in the tank and an insert incorporated within the housing and spaced from the diaphragm. The sensor housing is joined by a support tube to the body of a force balance meter which includes a pivoted force beam whose lower extermity is mechanically linked to a force measuring diaphragm disposed in a diaphragm chamber. The fill chamber of the sensor communicates with the diaphragm chamber of the meter by way of a capillary extended through the coupling tube. The fill chamber, the capillary and the diaphragm chamber contain hydraulic fluid, whereby tank liquid pressure imposed on the sensing diaphragm is transferred hydraulically to the force measuring diaphragm to deflect the force beam.

Abstract: Fuel compresses air in a bell mounted in fuel tank; compressed air is conducted to a gauge on instrument panel in a vehicle. The gauge includes an adjusting screw which is in an exposed position on the instrument panel so that a driver may readily calibrate the gauge to reflect the amount of fuel in the tank regardless of the size of the tank.

Abstract: A level-sensing head is suspended from a capstan above a vessel by means of a flexible link which is wound around the capstan to raise or lower that head upon rotation thereof in one direction or the other. Depending upon the position of the sensing head relative to the level of a liquid or other flowable mass in the vessel, the head causes emission of either of two control signals triggering a pulse generator to step a motor, coupled with the capstan, in a sense tending to maintain that relative level between two narrow limits. The output of the pulse generator is also fed to recording equipment and/or to a digital comparator designed to establish a preselected level which may be modified from time to time by a programmer. The flexible link may serve as an electrical or fluidic transmission channel for control signals originating at the sensing head; with a floating sensing head such control signals can also be generated by a torsion monitor inserted between the motor shaft and the capstan.