Abstract: A filter alert has a pressure differential switch that is responsive to positive and/or negative pressure through a pressure tube. The pressure tube is in fluid communication intermediate a positive-pressure or high-pressure side of an intended filter and a positive-pressure inlet aperture of a pressure-differential switch for indication of positive pressure across the intended filter. Optionally, the pressure tube is in fluid communication intermediate a negative-pressure or low-pressure side of a filter and a low-pressure inlet aperture of the pressure-differential switch for indication of low pressure across the filter. The pressure-differential switch actuates an actuator for alarm signals for desired action. The filter alert also includes a switch condition communication component, a filter condition alert and an alert container on which the pressure-differential switch is positioned.

Abstract: A vacuum cleaner comprises a housing having a floor-engaging nozzle fluidly interconnected with a filter bag in a closed filter bag chamber in the housing through a suction passageway, an exhaust vent in the filter bag chamber to exhaust filtered air exiting from the filter bag chamber and a vacuum motor provided in the housing to draw air from the floor-engaging nozzle to the filter bag. An exhaust filter is mounted in the exhaust vent. A sensor in the filter bag chamber detects a condition representative of the flow of air through the exhaust filter element and an exhaust filter indicator interconnected with the sensor provides a signal to a user when the condition reaches a predetermined level to indicate a clogged condition of the exhaust filter. A sensor and indicator can also be provided for the filter bag so that independent signals can be generated relating to the clogged condition of one or both of the filter bag and exhaust filter.

Abstract: A device for evaluating air removal is subjected to a sterilization process whose effectiveness is dependent on a sufficiently high vacuum being achieved. A closure or lid (20, 70) seals an opening into an interior chamber (12) of a container (10). The closure and container are mechanically interconnected, e.g., fricitonally, such that a preselected pressure differential across the closure is needed to release the closure. The friction or other mechanical interconnection level and a pressure in the interior chamber are selected such that when the exterior of the container is subject to a preselected vacuum, the closure releases. Ease or reliability of reading the indication is improved with a spring (50) for expelling the closure or a frangible member (56, 72) which is severed or irreversibly deformed as the closure releases.

Abstract: A differential pressure indicator has a piston across which inlet and outlet pressures are applied with a spring preventing movement of the piston until a predetermined differential pressure is exceeded. At this point, a port is opened to allow the inlet pressure to be applied to an indicator button to move the indicator button from a retracted position to an operative extended position to indicate that the pressure differential has been exceeded. The use of fluid pressure to operate the indicator button applies a large force to the indicator button and allows it to be securely held in the inoperative position to guard against accidental movement by high G-forces.

Abstract: An efficiency indicator for a separation system, such as a water filter, wherein a first volume of fluid is exposed, under a first pressure, to a separation medium and a second volume of fluid is recovered therefrom, under a second, lesser pressure. The indicator comprises a housing including an aperture and a biased piston rod in a tube driven between a first position and a second spaced-apart position by the differential between said first and second pressures when said second pressure represents an undesired loss of medium separating efficiency. The piston rod has a first reflective colored coating at one location on said rod and a second reflective colored coating at a second location. A sphere of optical transparent material is mounted so as to project through the aperture of the housing.

Abstract: An indicating device includes a housing that is separated into two sub-chambers by a flexible diaphragm. A indicating member is carried by the diaphragm so that the diaphragm and the indicating member move, within the housing, responsively to changes in the pressure of the air flowing through an air intake system caused by restrictions in or clogging of the air intake filter. The indicating device incorporates an electromechanical sensor for monitoring the position of the diaphragm and producing an output signal responsive thereto. In one embodiment, the sensor is a potentiometer which produces an output signal which varies continuously between a first value when the diaphragm is at its unrestricted position and a second value when the diaphragm is at its restricted position. In a second embodiment, the sensor includes a switching circuit which produces a switched output signal which varies between at least three states corresponding to three different diaphragm positions.

Abstract: A sensor for monitoring a cooling liquid circulating in a circuit of a heat exchanger of an automobile, for example, includes a support for mounting the sensor on a pipe of the circuit so that the liquid is in contact with at least a part of the sensor, a corrodible membrane in contact with the liquid, and a visual indicator reacting to the degree of corrosion of the liquid. The visual indicator includes a piston movable under the combined effect of the breaking of the corrodible membrane and of the pressure difference between inside and outside of the pipe, at least one seal mounted on the movable piston, and the visual indicator protruding from the pipe and/or from the support when the membrane is corroded.

Abstract: A filter monitoring device for use in monitoring the purity of a fluid through a filter includes a pressure differential sensing device in communication with the filter. The filter monitoring device defines an inlet port which is in communication with the supply of fluid upstream of the filter and an outlet port which is in communication with a supply of fluid downstream of the filter. The differential pressure sensing device comprises at least one movable device which is in contact with both the upstream and downstream supplies of fluid and moves in response to changes in the pressure differential of the fluid. Different total differential pressures are accommodated by corresponding stiffness of a biasing device. The differential pressure sensing device also comprises a distance sensing device which continuously measures or detects the distance of travel of the movable device.

Abstract: The invention relates to an audible altimeter for use by parachutists. The altimeter comprises a sensor means 6 for sensing ambient air pressure, an electronic processor 5, a sounder device 4 and control buttons 2,3. The electronic processor 5 is programmed to determine the height of the altimeter above ground level and send said signals to said sounder device 4 during the parachutist's descent causing said sounder device 4 to emit a first audible signal at a first predetermined height above ground level and a second audible signal at a second predetermined height.

Abstract: The internal fault indicator includes an open ended housing mounted in an opening in the wall of a transformer casing. An indicator lens is attached over a first open end of the housing and a diaphragm is attached over a second open end of the housing with the second end of the housing being positioned so that the diaphragm is subjected to internal pressure surges within the transformer. The diaphragm carries a trigger retainer which engages a trigger on an indicator shaft mounted for rotation within the housing. An indicator is mounted on the indicator shaft beneath the lens, and a bias spring is connected to the indicator shaft to bias the shaft toward rotation relative to the housing when the trigger is engaged with the trigger retainer.

Abstract: A filter indicator system for indicating when air flow through a filter is restricted includes an indicator mounted in a filter assembly downstream of the filter. The indicator includes a housing having a central space, a side wall, an end wall, an end inlet in the end wall, and a side outlet. A pop-up member is located in the central space and includes a signal portion which extends adjacent the end inlet. A moving device is then used for moving the pop-up member between a non-signalling position where the signal member does not extend noticeably through the end inlet and a signalling position where the signal portion extends noticeably through the end inlet.

Abstract: The present invention relates to an apparatus for detecting operational anomalies in a pressurized fluid circuit having a main pump, a fluid filter and a booster pump connected in series. The apparatus has an indicating detector to provide an indication of a system malfunction and a switching device connected to the indicating detector, as well as to various points in the pressurized fluid circuit, to enable the indicating detector to detect a malfunction in either the booster pump or the filter. The switching device has pressurized fluid inlets connected to a point upstream of the booster pump, a point between the booster pump and the filter inlet and to a point between the filter outlet and the inlet of the main, high pressure pump.

Abstract: A differential pressure indicator includes a housing having first and second pressure ports for fluid and a bore communicating with the pressure ports. A piston is movable in the bore between an actuated and an unactuated position in response to a pressure differential between the first and second pressure ports. A sensor senses movement of the piston between the actuated and the unactuated positions. A fluid control mechanism varies the effective surface area of the piston communicating with the first pressure port when the piston is in the unactuated position in accordance with variations in temperature of fluid at one of the pressure ports. The indicator is thereby prevented from actuating at low temperatures at which the fluid has a high viscosity.

Abstract: A device for continuously monitoring the difference in pressure of fluid in two closed spaces and separated by a dividing wall comprises an open-ended tubular housing which is secured to a rigid tube passing through and rotatably mounted in a horizontal passage in the wall with their axes inclined at an angle to one another. By rotably adjusting the housing with respect to the wall, the housing can be arranged to lie at a desired angle to the horizontal. The housing has a length three times its internal diameter and is transparent in end parts and opaque in a central part, each part being equal to a third of the total length of the housing. Two balls, each of a diameter slightly less than the internal diameter of the housing, are retained and free to roll within the housing, the ball remote from the wall being green and the other red.

Abstract: An apparatus including a housing secured to a filter web, wherein the housing includes a reciprocating rod directed orthogonally through the housing relative to the filter web, whereupon plugging of the filter web permits the rod to be directed through the housing to effect actuation of a switch therewithin. The rod mounts a magnet to track a plurality of contacts of a switch within the housing to effect actuation of an audible and visual alarm.

Abstract: A polyimide adhesive is applied in liquid form between surfaces of a pressure transducer glass surface and a glass pedestal tube and maintained at room temperature, or below, for a period of 10-15 hours to allow the adhesive solvent to evaporate. After such time, the temperature of the transducer and attached pedestal tube is elevated over a period of time to about 320.degree. C. to completely imidize the polyimide adhesive. The pedestal is then fixed within an opening in a base portion of a case, and electrical conductors are connected between pins in the case and transducer contacts. A cover is hermetically sealed to the case to thereby encase the transducer.

Abstract: A portable respirator system for supplying clean, breathable air to a hood or face mask is disclosed. The system can be carried on a waist belt and includes a housing containing air inlet and outlet plenums, and a battery powered, electric motor operated blower connected between the inlet and outlet plenums. The motor can be manually switched between high and low speed operation to supply high quantities of air upon demand caused by high respiration rate and otherwise supply lower quantities of air sufficient for low respiration rates to extend battery life between rechargings. A differential air pressure sensing switch is responsively connected for actuation when the difference between air pressure in the outlet plenum and the pressure of ambient atmosphere is less than a preselected value.

Abstract: A pressure indicator for use in a pneumatic circuit. A rolling diaphragm (14) is mounted within a housing (9,10) and divides the housing into first and second regions (15,16), one sealed from the other. The diaphragm has an outer sleeve section (18) and a connected inner cup section (19) lying within the outer sleeve section, the outer surface of the cup section and the inner surface of the sleeve section both being subject to pressure in the second region. An indicator (22) is seated within the cup section. The cup section is biased towards the first region against pressure therein, and into a position wherein the indicator lies substantially wholly within the cup section and is shielded from view thereby. The housing has a transparent section through which the indicator may be viewed as it moves out of the cup section in response to increasing pressure differential between the first and second regions.

Abstract: The disclosure describes an adapter assembly for a conventional fluid system having a filter unit mounted to a filter pad. The adapter assembly allows the pressure differential across the filter element to be conveniently measured by a differential pressure detector. The adapter assembly, which is mounted between the filter pad and the filter unit, generally comprises an adapter plate, a mechanism for attaching and sealing the adapter plate to the filter pad, a mechanism for attaching and sealing the filter unit to the adapter plate, and a fitting for connecting the differential pressure detector to the adapter plate. The adapter plate includes at least one aperture which allows fluid to flow between the inlet chamber of the filter pad and the inlet of the filter unit and another aperture which allows fluid to flow between the outlet of the filter unit and the outlet chamber of the filter pad.

Abstract: A flow rate sensor for use with an air filter channels air flow to energize an audible sound generator upon development of an air pressure differential within the sensor above a settable threshold, which pressure differential results from a reduction in the air flow rate through the air filter due to clogging of the air filter by filtered matter.

Abstract: A temperature compensating differential pressure indicating device having a lock-out feature requiring internal reset after actuation. The differential pressure responsive indicating device includes a case having an internal chamber and a piston reciprocably and sealingly disposed in the internal chamber. A piston follower is also reciprocably disposed in the internal chamber and abuts against the piston. A first biasing element biases the piston and the piston follower in a first direction while a second biasing element biases these components in the opposite direction, the second biasing element being weaker than the first biasing element. The piston is displaceable in response to the pressure differential between an inlet pressure and an outlet pressure. A shape memory alloy temperature responsive abutment permits the piston follower to move together with the piston at or above a predetermined temperature, while preventing motion of the piston follower below the predetermined temperature.

Abstract: To provide a filter bypass and indicator, in a pump having an inlet and an outlet with a filter therein, a bypass port is in communication with the outlet upstream of the filter. A bypass valve assembly is provided in the bypass port and is normally in a closed position to direct all flow from the pump inlet through the filter. The bypass valve assembly opens in response to a preselected pressure differential across the filter to divert at least a portion of flow from the inlet around the filter. In addition, the bypass valve assembly includes a switch actuator and the pump includes a switch positioned in proximity to the bypass valve assembly so as to be operable in response to movement of the switch actuator.

Abstract: A canister type vacuum cleaner includes a floor cleaning unit and a canister unit interconnected by a wand and hose assembly. The canister unit has a dust collection bag mounted in a dust collecting compartment by a dust bag mount. A suction fan evacuates the air within the dust collecting compartment causing dirt laden air to flow from the floor cleaning unit through the wand and hose assembly and into the dust bag through an intake port formed in the dust bag mount. The air is exhausted from the canister unit through a discharge port. A performance monitoring and indicating system provides information as to the operative condition of the vacuum cleaner by means of an "OK" light, a "No Bag" light, a "Check Bag" light and a "Check Hose" light. A dust bag sensor senses the differential pressure between the intake port and the dust collecting compartment and is actuated when a functional dust bag is properly mounted on the dust bag mount.

Abstract: A canister type vacuum cleaner includes a floor cleaning unit and a canister unit interconnected by a wand and hose assembly. The canister unit has a dust collection bag mounted in a dust collecting compartment by a pivotally movable dust bag mount that pivots to an operative position. A suction fan evacuates the air within the dust collecting compartment causing dirt laden air to flow from the floor cleaning unit through the wand and hose assembly and into the dust bag through an intake port formed in the dust bag mount. The air is exhausted from the canister unit through a discharge port. An operating condition monitoring and indicating system provides information as to the status of the dust bag and the wand and hose assembly by means of a check bag light and a check hose light.

Abstract: An excessive pressure differential indicating device for use with a filter in a liquid circulating system. The device has a reciprocable piston that reciprocates between a high pressure location, when the pressure differential is not excessive, and a low pressure location, when the pressure differential is excessive. The device has an indicator button with a magnetically conductive element, and the button is retained in a non-indicating position when the reciprocable piston is at the high pressure location by magnetic attraction between a permanent magnet carried by the reciprocable piston and the magnetically conductive element, a spring being provided to bias the indicator button to an indicating position when the reciprocable piston moves with the permanent magnet away from the indicator button to the low pressure location.

Abstract: A filter assembly for an automotive air handling system includes a frame adapted for demountable attachment to the engine side of the automotive firewall, and a filter slidably received in the frame. Springs are provided at the bottom of the frame for ejecting the filter partially out of the frame so that air can bypass the filter when the filter is clogged. A latchable door covers the access opening of the frame, holding the filter down against the bias of the springs until clogging is detected by a pressure-sensitive diaphragm. The diaphragm controls a release mechanism which unlatches the door when clogging of the filter causes an increase in the differential pressure across the filter.

Abstract: A device for the indication of dirt accumulation on an air intake filter by measuring the negative pressure in the clean air space of the filter, the device having a spring-biased diaphragm piston driving a pointer shaft by means of a bell crank with a gear segment, the pointer shaft carrying two diametrically oppositely arranged pointers with vertical and horizontal length portions moving in axial and radial portions of a pointer gap defined between the housing cover and an indicator dial carried by the cover. A ratchet mechanism serves to retain the pointer readout by blocking return movements of the indicator mechanism, the ratchet mechanism being releasable by means of a reset button on the cover of the device. The device is calibrated by means of an adjustable bell crank spring.

Abstract: A device for indicating differential pressures between first and second pressure sources comprising a housing with a bore and a piston member slidably disposed within the bore and dividing the bore into first and second chambers. The piston member includes a permanent magnet and the housing includes ducts for connecting the first pressure source to the first chamber and the second pressure source to the second chamber whereby the piston member is displaceably responsive to differences in pressure between the first and second pressure sources. The device further comprises indicators in cooperative arrangement with the piston member for indicating at least first and second predetermined differential pressure levels respectively corresponding to respective displacements of the piston member within the bore. The indicators are magnetically coupled to the piston permanent magnet such that they move from non-signalling to signalling positions in response to the respective displacements of the piston member.

Abstract: A pressure loss indicator employs a diaphragm which assumes one of two stable convex configured states in accordance with the pressure differential across the diaphragm. A trigger is responsive to the state of the diaphragm to release an indicator pin from the assembly upon occurrence of a reduction in the ambient pressure which results in a pressure differential across the diaphragm. A reference pressure is established in a reference chamber at one side of the diaphragm, the reference chamber being selectively isolated from the ambient pressure by a check valve.

Abstract: IA purge block is disclosed in which inlet, process, purge and vent ports are series connected in a ring or bridge. The channel or passageway connecting the inlet and purge ports comprises a flow sensor. The impedance to gas flow of each channel is different from the others. The impedances are chosen such that improper operating conditions cause an imbalance in the flow which is detected by the flow sensor. During normal operation of the system in which the purge block is used, the flow sensor acts as an excess flow detector by comparing the flow through itself with the flow through a parallel, but more restrictive, path within the purge block.

Abstract: The present disclosure relates to a pressure change indicator useful in determining whether the pressure-change/time values are exceeding safe levels. The device is constructed of clear plastic and employs a ball indicator in a cylindrical chamber operatively connected to an air reservoir. The reservoir is filled at the maximum dive depth with ambient air until air leaks from air outlets in the wall of the reservoir. As the air expands during the ascent it exits through the outlets. At excessive ascent rates, air cannot escape through the outlet fast enough and forces the ball indicator down the chamber past an indicator line alerting the diver.

Abstract: A differential pressure indicator for use with a filter providing dual indication to indicate both a bypass condition as well as an impending bypass condition. The indicator includes a pressure detector in the form of a piston carrying a pair of permanent magnets. A pair of cylinders each carrying a permanent magnet are concentrically disposed around the permanent magnets carried by the piston. As the differential pressure increases, the piston moves pulling the permanent magnets affixed thereto through the concentrically disposed magnets and as a result of magnetic force interaction the concentrically disposed cylinders move to expose first one and then the other of the cylinders to provide the signals representative of the impending bypass as well as bypass differential pressure being sensed.

Abstract: An operating condition indicator for vacuum cleaners which has a diaphragm switch which responds to vacuum and a luminous indicating device. The operating-condition indicator is intended for vacuum cleaners which have a turboblower which acts directly on the suction connection and is arranged in front of the dust bag, the pressure detected in the region of the suction opening becoming less as the dust bag becomes increasingly full. The vacuum is detected at the suction opening and fed to a diaphragm switch having additional spring biasing, as a result of which an indication of readiness for operation is obtained when the motor is off and, in addition, a warning indication is given when the dust bag is excessively full, without the necessity of actuating a switch.

Abstract: A differential pressure indicator is disclosed, providing an indication upon detection of a predetermined level of differential pressure in a fluid pressure system. The device includes a piston mounted to a rolling lip diaphragm, with the differential pressure exerted across the piston, which is thereby moved against the resistance of a bias spring from a non-display position to a display position upon development of the predetermined differential pressure. The piston is viewable in the display position through a 360.degree. window formed integrally with the housing or by a separate transparent ring assembled into the housing. Valving may also be controlled by the piston movement, enabling communication of fluid pressure to an outlet port for activation of a fluid pressure operated audible signal or other indicator device.

Abstract: An air filter restriction indicating device communicating with the supply of air passing from an air filter to the air intake of an internal combustion engine. The indicating device senses a decrease in the supply of air drawn through the air filter by the engine based upon changes in the amount of vacuum in the negative side of the air supply, the amount of restriction being indicated by the movement of an indicating device. Improved means included in the indicating device senses the movement of the indicating device and progressively locks the indicating device into various indicating positions as the vacuum increases due to an increased restriction of the filter, so that the maximum reading of restriction achieved during engine operation remains visible to the operator or maintenance personnel even after the engine is turned off.

Abstract: A differential pressure indicating device which is temperature compensated and includes a piston responsive to a pressure differential between inlet and outlet pressures. The piston is retained in a normal or first position by the force of a spring holding mechanism. The spring holding mechanism releases the piston at a predetermined excessive differential pressure condition to a second position. As this occurs, the piston actuates an indicating member to an indicating condition. A temperature sensitive bimetallic strip is provided to permit the piston to move to the second condition without activating the indicator member when the temperature of the fluid is below a predetermined temperature.

Abstract: A "snap action" early warning bypass valve assembly (2), responsive to fluid pressure differentials and/or low pressure, functions as both an electrical switch to provide an indication of low pressure or an impending fluid bypass and as a mechanical valve to actually implement the fluid bypass. The valve assembly includes a sealing piston (24, 124) supported by a retaining surface (18, 106) having a central bore (22, 110) formed therein. The sealing piston (24, 124) contains a bypass aperture (36) and is shaped to present a differential sealing area (39) to fluid circulating within the central bore (22, 110). A spring-biased bypass disc (42, 134) covers the bypass aperture (36) to present a central sealing area (45) to fluid within the central bore (22,110). A first pressure differential acting simultaneously across the central (45) and differential (39) sealing areas forces piston (24) into contact with an electrical terminal pin (48,92,126) thus energizing an alarm circuit (48-64,90).

Abstract: A pressure detection arrangement embedded between the skin of a portion of the body and a means used to surround and/or immobilize that particular part of the body, such as a cast. The pressure detection arrangement is a bifurcated capsule having a reservoir cavity and an indicator cavity. A colored fluid is initially contained only within the reservoir cavity by either a frangible disc across the conjunction of the indicator cavity with the reservoir cavity or an extensible bladder within the reservoir cavity. The indicator cavity is transparent or translucent and protrudes through the cast to regions external thereto.If there is swelling of the limb due to medical complications, the skin presses against the capsule and either breaks the frangible disc allowing the colored fluid to pass into the indicator cavity or forces the extensible bladder into the indicator cavity of the capsule. Both methods provide a visual indication in the indicator cavity of excessive pressure on the limb.

Abstract: A fill-up indication arrangement for a vacuum cleaner includes a diaphragm adapted to move up and down in response to a pressure build-up in the vacuum cleaner and an indicator disc connected to the diaphragm through a pivotable gear sector and a stop on the indicator disc, which stop engages with the teeth of the gear sector when the indicator disc takes its angular position thus indicating that a filter bag contained in the vacuum cleaner is full and should be replaced.

Abstract: There is provided a full bag indicator which is calibrated by movement of it along the structure it is mounted to, to thereby vary an aperture leading into the full bag indicator.

Abstract: A system to monitor the amount of erosion taking place within a pipe in which a point of reduced strength of the pipe is made by drilling a hole or notch to a preselected depth in a selected portion of the pipe wall. A hollow casing is provided around the point of reduced strength to provide a sealed zone. A conduit in the hollow casing is connected to a sensing device to monitor pressure changes when pipe failure occurs at the hole or notch.

Abstract: A versatile filter structure adaptable for use in differently ported configurations includes accommodation for variations of bypass and shutoff valving and for filter element replacement from either end or centrally of the structure. A head casting is secured to a tubular housing and either may be the mounting device for the filter. A funnel shaped diverter having an oblique edge is removably mounted in the head casting and provides separation between inlet and outlet portions of the filter structure by means of an eliptical o-ring seal at the edge which engages the interior of the head casting. The diverter provides a smooth transition for fluid flow to the interior of the filter, supports one end of the filter element in the tubular housing, optionally houses a shutoff valve operative automatically upon filter element removal, and further houses a bypass valve for safeguarding against filter element blockage.

Abstract: A "snap action" early warning bypass valve assembly (2) responsive to fluid pressure differentials functions as both an electrical switch to provide an indication at impending fluid bypass and as a mechanical valve to actually implement the fluid bypass. The valve assembly includes a piston (24) supported by a retaining surface (18,106) having a central bore (22,110) formed therein. The piston (24) contains a bypass aperture (36) and is shaped to present a differential sealing area (39) to fluid circulating within the central bore (22,110). A spring-biased bypass disc (42) covers the bypass aperture (36) to present a central sealing area (45) to fluid within the central bore (22,110). A first pressure differential acting simultaneously across the central (45) and differential (39) sealing areas forces piston (24) into contact with an electrical terminal pin (48,92), thus energizing an alarm circuit (48-64,90).

Abstract: A vacuum cleaner has a housing with an inlet which can be closed by a cover. A dust bag can be installed in the housing suspended from a plate which is located inwardly of the cover and has two openings both of which communicate with the interior of the bag. The cover carries a suction nipple which sealingly enters one of the openings when the cover is closed. A connecting nipple is also carried by the cover and sealingly enters the other opening when the cover is closed. The entire connecting nipple, or a diaphragm mounted in the same, moves in direction towards the cover when, in response to increasing filling of the bag and clogging of the filter pores thereof, the pressure in the bag rises to a level higher than the pressure at the other side of the connecting nipple or diaphragm, respectively. This movement is transmitted to an indicator observable from the exterior of the vacuum cleaner and provides an indication of the degree to which the bag is filled.

Abstract: A photo-electric pressure relief indicator for a fluid system wherein a housing is provided with an opening for connection in fluid communication with the system and provided with a vent spaced from the opening, a rupturable diaphragm extending across the housing to close communication between the opening and vent, a reflector on the diaphragm, and a photo-electric circuit reflecting from the reflector for sensing movement of the latter caused by rupture of the diaphragm.

Abstract: An indicator device for indicating when a prechosen pressure difference has been exceeded comprises a casing having two ports separated by a resilient diaphragm with an aperture therein, and a movable member urged into sealing relation with said aperture so as to prevent leakage therethrough, the configuration of the member and the aperture being selected so that, in use, the application of a prechosen pressure differential between said ports will cause the member to partly pass through the aperture to a position whereat it is retained by the diaphragm, said member being provided with means for indicating that it has been so retained.

Abstract: A device for evacuating air from a container comprises a closing cover, to sealingly close an opening of a container, having an opening closable by a valve. The closing cover further has at its upper surface an annular flange surrounding the opening therein. The device also comprises a separable evacuating pump having a cylinder which may be sealingly connected to the closing cover by pressing the cylinder over the flange until the end surface of the cylinder engages the part of the closing cover from which the annular flange projects, in order to achieve a sealing action in two planes substantially perpendicular to each other, and also locking the pump against lateral displacement relative to the closing cover.

Abstract: The neck of a bottle is closed and sealed by a one-piece cap having a cylindrical portion which surrounds the neck, a deformable end wall which extends across the open end of the neck, and a flexible hose which is integral with the end wall. The outer side of the end wall has a diametrically extending projection consisting of two discrete sections having flat elongated outer surfaces which are parallel to each other when the pressure in the bottle equals the pressure of the surrounding atmosphere and which are inclined with respect to each other when the pressure inthe interior of the bottle is reduced below atmospheric pressure. The person observing the surfaces of the two sections can ascertain the presence and absence as well as the extent of pressure differential between the interior and exterior of the bottle.

Abstract: A flow sensor is provided, responsive to fluid flows within a range from above a predetermined minimum to below a predetermined maximum, to indicate that flow is within that range and the minimum flow has been exceeded, but nonresponsive to fluid flows below the predetermind minimum or above the predetermined maximum, to avoid giving a false indication of fluid flow, comprising a flow-responsive valve and a differential pressure indicator.

Abstract: A flow sensor is provided responsive to fluid leakage flows within a range from above a predetermined minimum to below a predetermined maximum, to indicate that leakage flow is within that range and/or that maximum leakage flow has been exceeded, but nonresponsive to fluid flows below the predetermined minimum or above the predetermined maximum, to avoid giving a false indication of fluid leakage flow, comprising a flow responsive valve and a differential pressure indicator sensing differential pressure between fluid leakage flow and normal fluid flow at the valve.