Abstract: A device and system for purifying a fluid is provided. The system includes a tank having an interior space and a media container disposed within the interior space. A valve is provided that cooperates with an element within the interior, the valve being movable between an open and a closed position. The valve being biased to the open position when the element is not positioned within the interior space, wherein the interior space is fluidly coupled to the atmosphere in the open position. The valve further being configured to move to a closed position when the element is positioned within the interior space.

Abstract: A reject valve of a reverse osmosis device, which is especially suited for brackish water reverse osmosis devices, which require a low system pressure less than 15bar. The valve keeps the system pressure substantially constant in a pre-defined range of the reject volume. The size of the inflow channel is adjusted by a spring-operated cone, which never entirely closes the channel, which forms a constant throttle until the pressure of the inflow has risen to approximately three quarters of the pressure arranged by the spring and prevailing at maximum volume of the reject flow. This operation is arranged structurally such that onto the shaft of the cone is fixedly supported a transverse plate abutting the inner wall of the body, which as pressed by the compression spring is supported by the end of an element connected to the end of the body, wherein the cone is in its lowest position.

Abstract: Separation of wirings formed on an organic passivation film is prevented in an organic EL display device or a liquid crystal display device. The organic EL display device includes a TFT formed on a substrate and an organic passivation film formed to cover the TFT. An intermediate film containing SiO or SiN is formed to cover the organic passivation film. An insulation film formed with an organic material is formed on the intermediate film. A reflective electrode is formed on the intermediate film. The reflective electrode is connected to the TFT via a through-hole formed in the organic passivation film and a through-hole formed in the intermediate film.

Abstract: An actuator is designed to control airflow in HVAC systems by opening and closing a damper. A slippage detector may be secured to a damper shaft to measure movement of the damper shaft. This measured movement may be compared to the expected movement of the damper shaft as indicated by the movement of a rotatable output of the actuator.

Abstract: A vehicle air intake assembly is disclosed. The assembly includes a base member having an aperture configured to allow air to flow through the base member and into an engine and an outer member spaced from the base member to position an air filter between the outer member and the base member.

Abstract: The invention relates to a container for drainage of fluids or wound secretion, comprising an inlet opening to connect with a drainage line and an outlet opening for releasing waste air accumulated inside the container during drainage, which is characterized in that the container is pre-evacuated, and the outlet opening is sealable, so that the container is transferable in a first and in a second operating condition, wherein in the first operating condition the outlet opening is sealed, so that a suction can be achieved at the inlet opening caused by the vacuum inside the container, and in the second operating condition the outlet opening is opened, so that air can enter the container through the outlet opening and neutralize the vacuum present inside the container.

Abstract: Systems, methods, and devices for sealing a container are described and disclosed. A system includes a lid assembly configured to seal an opening of a container and a coupler assembly configured to be disposed within a recessed portion of the lid assembly. The lid assembly includes a recessed portion configured to facilitate coupling the lid assembly with an external vacuum source. The lid assembly includes a hole disposed within the recessed portion and a ball seal disposed in the hole, wherein the ball seal is configured to seal the hole in a closed position when a vacuum pressure is created within the container. The lid assembly includes a gasket cavity disposed within the lid assembly, wherein the gasket cavity is configured to align a gasket for creating a seal between the lid assembly and the container. The coupler assembly includes a coupler body, a coupler seal, and a vacuum port.

Abstract: A controllable primary switch for isolating a transformer from a power grid or network. The controllable primary switch is mountable within and integral to the transformer and is electrically connected to high voltage feeder cables to allow the transformer to be disconnected from the power grid or network. The controllable primary switch includes one or more vacuum interrupters having first and second electrical switch contacts mounted inside the casing, an actuator for moving the second switch contact relative to the first switch contact in each of the one or more vacuum interrupters, and a handle connected to the actuator. The handle engages the actuator to move the second switch contact relative to the first switch contact.

Abstract: A method of identifying operational modes experienced by a user during a jump from an aircraft may comprise estimating a user altitude and a user descent rate, based on a set of navigation state data vectors. The method may further comprise determining that the user is ready to transition from a flight mode to a descent mode when the user altitude is above a jump altitude threshold, and a variation of the user altitude is below a predetermined altitude variation threshold. After determining that the user is ready to transition from the flight mode to the descent mode, the method further comprises determining that the user has transitioned from a flight mode to a descent mode when a user ground speed is below a ground speed threshold, and one or both of (i) a GNSS position error estimate, and (ii) the user descent rate estimate, indicates a jump signature.

Abstract: An apparatus and method for monitoring reduced fluid flow through a filter. A filter, more particularly a fluid flow filter or an air filter when contaminated can suffer from a reduced fluid flow, which will often deform to match the fluid flow or more particularly in the case of an air filter—the air flow.

Abstract: Exemplary embodiments provide a packing leak detection system for leaks or discharge of a volatile material which discharge into the environment is subject to regulation. The system contains a compressor apparatus including a compressor cylinder, a compressor piston, a compressor piston rod positioned in a packing case, wherein a volatile material being compressed by the compressor apparatus leaks from the packing case. Also provided is a leak detector sized and configured to detect and monitor leaks of the volatile material from the packing case, as well as an apparatus for capturing and collecting volatile material which may leak from said leak detector. Methods of assessing leaks of a volatile material subject to environmental regulation are also provided.

Abstract: Methods for detecting a patient disconnecting from a continuous positive airway pressure (CPAP) therapy device are disclosed. A cyclical pressure difference signal is derived based upon measurements from a patient interface pressure sensor and from a source pressure sensor. The pressure difference signal is integrated to generate a resultant integral signal for each respiratory cycle, which is comprised of at least one inspiratory phase and at least one expiratory phase as represented by the corresponding portions of the pressure difference signal. A pressure source of the CPAP therapy device is deactivated in response to a disconnect condition being evaluated from the integral signal. In one embodiment, the disconnect condition is the integral signal exceeding a predefined disconnect threshold. In other, it is a slope value corresponding to a rate of increase of the integral signal exceeding a predefined threshold for a predefined duration.

Abstract: A particulate-accommodating fluid flow directing apparatus comprises a failure detection housing containing a flow directing insert, the housing serving as a pressure boundary; failure at any location along the insert being detectable by means associated with the housing. The insert can be manufactured of erosion resistant materials, including non-ductile materials such as ceramics. The insert is sealed to the housing at an inlet and a discharge forming a pressure chamber between the insert and housing. The pressure chamber can be maintained at a pad pressure complementary to the process pressure, the pad pressure being maintained and monitored for indication of insert failure.

Abstract: A bypass valve having an adjustable flow resistance for a device through which a fluid medium flows. The valve includes a seat and a body which is biased closed, and which is movable in the opening direction by a fluid medium pressure difference between the inflow and the outflow side of the valve when the pressure difference exceeds a threshold. A bypass flow path connects the inflow side to the outflow side through the seat. The bypass valve includes a screen disposed in the bypass flow path. The valve body has two different open positions that depend on the fluid medium pressure difference. The entire cross-section of the bypass flow path is covered by the screen in a first valve body open position with a lower pressure difference, and a screen-free bypass flow path cross-section is exposed in a second valve body open position with a greater pressure difference.

Abstract: There is provided a robot cleaner including a main body, a suction unit that sucks air including foreign substances into the main body, a moving unit that moves the main body, a dust collecting unit that has a filter for filtering the foreign substances included in the air sucked by the suction unit and a dust collecting case that collects the foreign substances filtered by the filter, and a detection unit that detects whether or not the filter is attached to the main body.

Abstract: A contaminant detection system for use in a fluid distribution system includes a first detector assembly including an inlet housing and detector screen through which fluid in the fluid distribution system passes and a first sensor to detect a first type of contaminant caught in the detector screen; and a second detector assembly including a second sensor which activates when the inlet housing or detector screen is clogged to detect whether the fluid contains a second type of contaminant when the first sensor does not detect the first type of contaminant.

Abstract: A filtration device is disclosed. The device includes a filter inlet, a filter outlet, and a filter flow path from the filter inlet to the filter outlet. A filter in the filter flow path filters contaminants from lubricant flowing from a lubricant supply to a lubricant destination. A bypass flow path bypasses the filter in the event the filter becomes clogged. The bypass flow path has a bypass inlet in fluid communication with the filter flow path at a location upstream from the filter and a bypass outlet separate from the filter outlet and not in fluid communication with the filter outlet. The bypass outlet is normally closed to permit flow along the filter flow path and opens if the filter becomes clogged so that lubricant is directed along the bypass flow path and through the bypass outlet for disposal without going to the lubricant destination.

Abstract: A pressure differential indicator that eliminates the risk of providing a false positive due to fluid contamination. The invention has an electrically insulated barrier between the “hot” pin and the grounded housing without the need for a hermetic seal. The indicator can be manufactured at a greater efficiency and lower cost than is found with prior art pressure differential indicators. It has a piston that can be easily oriented to yield either a normally closed or normally open position. The indicator has at least one protrusion on a plastic overmold to engage the swage collar and resist axial rotation of the pin. A pressure seal interrupting the plastic overmold sections and exposing the underlying metal to allow for an O-ring seal with no potential leak path between plastic and metal. Finally, the pressure differential indicator has all moving components contained within a single cavity.

Abstract: A clog indicating device indicating clogging of a dust collecting filter in a dust collector is disclosed. The dust collector includes on an upper region of its casing an exhaust port opening upward, and a cover member is mounted interspatially above the exhaust port. A colored indicating float is so located as to be movable upward between the exhaust port and the cover member due to pressure of an air exhausted from the exhaust port. Clogging of a dust collecting filter is indicated according to a degree of exposure or a position in an up and down direction of the indicating float between the exhaust port and the cover member.

Abstract: A compressor in fluid communication with a filter is disclosed. A gauge is used with the filter and is configured to react to a pressure drop across the filter and indicate an increasing amount of contaminants captured by the filter. The gauge is provided with a dial having multiple scales thereon. A unitary indicator, such as a needle, is further provided with multiple indicating portions which can be used to indicate a property of the fluid, such as a differential pressure across the filter, and can simultaneously indicate a property, such as an economic cost associated with running the compressor with a filter having accumulated contaminants.

Abstract: A pressure indicator system is provided for use a gas storage container. The gas storage container has an interior that stores gas, and a housing having a cavity that opens to atmosphere and which communicates with the interior of the container. A piston or diaphragm communicates with a stem that extends through the cavity and into atmosphere, with the stem having a pressure indicator provided around an upper portion of the stem. A resilient element is retained in the cavity and normally biases the piston or diaphragm towards the interior of the container. The existence of pressure in the container opposes the normal bias of the resilient element to cause the stem and its pressure indicator to extend outside the cavity.

Abstract: This invention relates to a dust indicator in a vacuum cleaner, which dust indicator (200) is arranged in a wall (102) at least partly defining a space of the vacuum cleaner that is set under negative pressure with respect to the outside of the wall during operation of the vacuum cleaner. The dust indicator comprises an air channel (211) having an air inlet (212) arranged at an outer side of the wall, and an air outlet (213) arranged at an inner side of the wall, such that an airflow is directed into the space during operation of the vacuum cleaner due to the negative pressure. The dust indicator further comprises a sensor (220) arranged for detecting dust by means of sending and/or receiving an electromagnetic signal which is transmitted through the space. The air channel is arranged such that the airflow prevents dust from sticking in an area of the path of the electromagnetic signal of the sensor.

Abstract: A real-time monitoring system that monitors various aspects of the operation of a refrigerant-cycle system is described. In one embodiment, the system includes a processor that measures power provided to the refrigerant-cycle system and that gathers data from one or more sensors and uses the sensor data to calculate a figure of merit related to the efficiency of the system. In one embodiment, the sensors include one or more of the following sensors: a suction line temperature sensor, a suction line pressure sensor, a suction line flow sensor, a hot gas line temperature sensor, a hot gas line pressure sensor, a hot gas line flow sensor, a liquid line temperature sensor, a liquid line pressure sensor, a liquid line flow sensor. In one embodiment, the sensors include one or more of an evaporator air temperature input sensor, an evaporator air temperature output sensor, an evaporator air flow sensor, an evaporator air humidity sensor, and a differential pressure sensor.

Abstract: A filtration system for a gas powered concrete saw allows the user to inspect and/or determine how much dust is accumulated in the filter. In addition, manual filter cleaners are provided to allow the user to easily clean the filter without needing to open up the tool. In addition, the system is provided to deactivate the tool or notify the user if no filter is being utilized, or the filter is damaged. The system can also provide system lock out in the case of a missing or damaged filter. In addition, automatic methods are also provided to allow cleaning of the filter.

Abstract: A filter assembly for use with compressor assemblies such as oxygen concentrators, ventilators and other breathing apparatus including a compartmented housing member having at least one inlet opening, an outlet opening, a filter member, and an adjustment member associated with the at least one outlet opening for varying the size of the at least one outlet opening for adjusting the amount of ambient air entering the filter assembly.

Abstract: A bypass factor of an evaporator is used to indicate when an air filter of an HVAC is clogged. The bypass factor represents the amount of air that is bypassed without direct contact with the evaporator. As the air filter clogs, the bypass factor decreases. The bypass factor can also be used for early detection of clogging of the air filter. A first bypass factor is calculated by using the temperature measurements, and a second bypass factor is calculated by using the airflow rate of the air. The difference between the two bypass factors determines the error. An increase in the error indicates that the air filter is clogged. A coefficient of performance of the evaporator can also be calculated to detect if the air filter is clogged. A decrease in the coefficient of performance indicates that the air filter is clogged.

Abstract: An indicator suitable for signaling restricted flow of a fluid through a filter mounted in a filter assembly includes a housing having an inner cavity. A diaphragm disposed within the housing separates the inner cavity into first and second chambers and deflects from a neutral position in response to applied pressures within the first and second chambers. A tab assembly opposite the diaphragm includes a spring-loaded flag moveable from a first position within the housing to a second position outside the housing. A pin operably coupled to the diaphragm holds the spring-loaded flag within the housing when the diaphragm is in the neutral position. In response to the diaphragm being deflected sufficiently from the neutral position to release the pin, the spring-loaded flag travels to the second position outside the housing, thereby indicating a restricted flow condition for the filter.

Abstract: A display provides an indication of the remaining useful life of a filter element by providing a visible level of fluid in the display corresponding to the remaining useful life. The fluid level is adjusted by a valve responsive to a pressure differential across the filter element. An increasing pressure differential produces an increased fluid level in the display. The display may be provided with markings indicating that a particular fluid level in the display corresponds to the need to change a filter cartridge containing the filter element.

Abstract: Disclosed is a pneumatic actuator movement indicator comprising a housing adapted to be connected in series between a pneumatic actuator and a source of pressurized fluid for the actuator, and an indicator located in, and having an equilibrium position in, the housing. The housing includes a first chamber for placing the housing in fluid communication with said actuator at a pressure P1, and a second chamber for placing the housing in fluid communication with said source of pressurized fluid at a pressure P2. The indicator is movable in the housing in response to a difference between P1 and P2. Movement of the pneumatic actuator produces a difference between P1 and P2; and in response to this difference, the indicator moves away from its equilibrium position, indicating the movement of the pneumatic actuator.

Abstract: A fluid system pressure indicator is adapted for use in fluid systems having a filter element. The fluid system force indicator includes a housing partitioned to be exposed to the fluid system to provide transmission of a mechanical force between these partitioned environments to indicate the fluid pressure. This exterior shape change is such that it can be identified through tactile means not requiring visual identification.

Abstract: A pressure actuated electrical switch and indicator to indicate to a user that a filter vacuum cleaner requires cleaning or replacing. In a first embodiment, the pressure actuated electrical switch measures the pressure present between the filter media and the flow inducing device to determine whether a minimum absolute pressure threshold has been exceeded. The pressure actuated switch has a chamber with two electrical leads that are connected when the pressure in the vacuum cleaner raises above a predetermined level. A tube from the chamber to the vacuum cleaner housing draws a conductive part into contact with both leads. In additional embodiments, the pressure measure is the difference in air pressure above and below the filter media, or the difference in air pressure between the pressure in the air stream between the filter media and the flow inducing source, and the ambient air pressure.

Abstract: An air supply system for a clean room with a critical machine. An intake duct connects the exterior of the clean room to a make-up air unit, and is configured to transport external air into the make-up air unit. A first air duct connects the make-up air unit to an air conditioning cabinet including a first chemical filter, and is configured to transport the air flowing through the make-up air unit into the air conditioning cabinet. The first chemical filter removes airborne molecular contamination from the air transported into the air conditioning cabinet. A second air duct connects the air conditioning cabinet to the critical machine, and is configured to transport the air flowing through the first chemical filter of the air conditioning cabinet into the critical machine. An exhaust duct connects the critical machine to the exterior of the clean room, discharging waste gas produced in the critical machine.

Abstract: A real-time monitoring system that monitors various aspects of the operation of a refrigerant-cycle system is described. In one embodiment, the system includes a processor that measures power provided to the refrigerant-cycle system and that gathers data from one or more sensors and uses the sensor data to calculate a figure of merit related to the efficiency of the system. In one embodiment, the sensors include one or more of the following sensors: a suction line temperature sensor, a suction line pressure sensor, a suction line flow sensor, a hot gas line temperature sensor, a hot gas line pressure sensor, a hot gas line flow sensor, a liquid line temperature sensor, a liquid line pressure sensor, a liquid line flow sensor. In one embodiment, the sensors include one or more of an evaporator air temperature input sensor, an evaporator air temperature output sensor, an evaporator air flow sensor, an evaporator air humidity sensor, and a differential pressure sensor.

Abstract: A device used with fluid canisters comprising a transparent body allowing the viewing of movement within the body having a minor and major cavity with a float indicator and float seat within the minor cavity. An inhaler top and bottom fits each end of the body forming an airtight chamber within the major and minor cavity above the float, the top having a seat to accept a canister and a nozzle aperture to accept a nozzle of the canister oriented to release fluid from the canister into the major cavity. An inlet through the minor cavity below the seat maintains pressure equal to pressure outside of the body within the minor cavity. Inhalation through a mouthpiece and one way valve reduces pressure within the major and minor cavity above the float drawing fluid through the one way valve creating a pressure difference across the float causing it to move.

Abstract: A pressure indicator and a corresponding method are disclosed, the pressure indicator comprising a display diaphragm, optionally transparent, and an indicator diaphragm coupled to and in fluid communication with the display diaphragm. In use, pressure is applied to the diaphragms, which may be amplified, whereby a change in the pressure applied causes relative movement between the diaphragms which is observable either on the outer surface of the display diaphragm or through the display diaphragm. The diaphragms may form a compartment preferably containing a liquid or gel. The indicator diaphragm may bear a recognizable configuration or pattern which can be colored and may comprise a symbol or graphic projecting from its surface. The configuration or pattern may comprise at least two components, each component corresponding to a different pressure. Also disclosed is an inflatable device, especially a football or a tire, comprising such a pressure indicator.

Abstract: The present disclosure relates to a restriction indicator for an air cleaner system of an internal combustion engine. The restriction indicator includes a housing divided into first and second chambers by a diaphragm. A signal member is connected to the diaphragm. The signal member is moveable along an axis between a reset position and a first indicator position, and defines an axial opening within which a first retaining shoulder is located. A guide member is provided for guiding the signal member as the signal member is moved between the reset position and the first axial position. A retaining member is provided for retaining the signal member in the first indicator position. The retaining member extends within the axial opening of the signal member and includes at least two fingers that project radially outward from the axis. The fingers are configured to engage the first retaining shoulder to retain the signal member in the first indicator position.

Abstract: An air filter sensor kit and method of using the same for permitting a person to modify the filtering portion of a heating or cooling system that uses an air filter to enable the determination of when the air filter is dirty and needs changing. The air filter sensor kit includes an air filter sensor with a portion shaped for insertion through the air filter and a portion with an indicator for indicating the condition of the air filter. The kit includes an air filter sensor connecting and support member for connecting the air filter sensor to an air filter grill and for supporting the air filter sensor and a cutting tool for cutting a hole in an air filter grill to allow the passage of a portion of the air filter sensor connecting and support member to permit a portion of the air filter sensor to be inserted through the air filter. The air filter sensor kit also includes a cutting tool guide that is adjustable to conform to various configurations of air filter grills.

Abstract: A liquid filter (10) housing an annular filter element (16) has an annular space or inlet chamber (24) between the filter element and the housing and viewable through the housing such that an operator can see the level of liquid in the inlet chamber as an indication of when to replace the filter element, the higher the level of liquid in the inlet chamber the greater the pressure drop across the filter element. A change interval plugging indicator (102), preferably part of the filter element, is provided by a gas trap and pressure responsive release mechanism (104) trapping gas in the upper section (23) of the inlet chamber until a designated release pressure is reached, corresponding to a desired terminal pressure, to prevent premature plugging indication otherwise indicated by rising liquid level in the inlet chamber. Accurate and reliable calibration is enabled by separating the filtration function and the plugging indication function.

Abstract: A detector for mounting to an air filter provides a signal if the filter is dirty. The detector has a housing mounted to the air filter. The housing has a cavity with a diaphragm. An upstream air inlet leads from an exterior of the housing to an upstream side of the diaphragm. A downstream air inlet leading from the exterior of the housing to a downstream side of the diaphragm. A stationary electrical contact is stationarily mounted in the cavity and normally spaced from the downstream side of the diaphragm. A movable electrical contact is mounted to the downstream side of the diaphragm for movement therewith. An electrical circuit is connected to the electrical contacts, so that movement of the diaphragm due to a sufficient difference in air pressure between the upstream and downstream air inlets causes the contacts to engage each other and causes the electrical circuit to provide a signal.

Abstract: An annular space or inlet chamber 24 between the filter element 16 and housing of a liquid filter is viewable such that an operator can see the level of liquid in the inlet chamber as an indication of when to replace the filter element: the higher the liquid level, the greater the pressure drop across the filter element. A change interval plugging indicator includes a porous outer wrap 50 that traps gas in an upper section 23 of the inlet chamber below a designated release pressure and releases trapped gas upon attainment of the release pressure causing a rapid rise in liquid level within the housing and corresponding to a desired terminal pressure. The indicator prevents premature plugging indication otherwise indicated by a slowly rising liquid in the chamber. Accurate and reliable calibration is enabled by separating the filtering and indicating functions.

Abstract: The present disclosure relates to a restriction indicator for an air cleaner system of an internal combustion engine. The restriction indicator includes a housing divided into first and second chambers by a diaphragm. A signal member is connected to the diaphragm. The signal member is moveable along an axis between a reset position and a first indicator position, and defines an axial opening within which a first retaining shoulder is located. A guide member is provided for guiding the signal member as the signal member is moved between the reset position and the first axial position. A retaining member is provided for retaining the signal member in the first indicator position. The retaining member extends within the axial opening of the signal member and includes at least two fingers that project radially outward from the axis. The fingers are configured to engage the first retaining shoulder to retain the signal member in the first indicator position.

Abstract: A pressure indication device including a housing with an opening in communication with a pressure vessel, a plunger moveable in the housing between a pressurized position and a non-pressurized position, a seal between the opening and the plunger, an indicator over the plunger and biased into a flag position, and a locking mechanism for holding the indicator in a set position until the plunger moves to the non-pressurized position whereupon the indicator returns to the flag position.

Abstract: The invention provides an apparatus and method to monitor air filter restriction within an air cleaner system of a motor vehicle. The invention uses a quick connect couplig to allow fluid communication between a restriction gauge and the air cleaner housing and also provides a means of attaching the restriction gauge or a remote tubing connector to the air cleaner housing. The quick connect coupling is located within an axial bore, generally within a conduit in the housing. A portion of the filtered air is drawn from the air cleaner housing through the quick connect coupling and into the restriction gauge, where the pressure is measured and the amount of air filter restriction is gauged.

Abstract: A filter assembly for filtering pond or aquarium water includes a container (1,2) with an inlet chamber (15) having an upstream region (36) and a downstream outlet (13) leading to an outlet chamber (22). A filter (16) is positioned in the inlet chamber (15) between the upstream region (36) and the outlet (13). In use, progressive clogging of the filter causes the water pressure in the upstream region (36) to rise until it reaches a predetermined threshold when a normally-closed relief valve (28,29) opens to allow water to pass from the upstream region (36) to the outlet chamber (22) without passing through the filter (16). The valve has a coloured valve stem (28) providing a visual indication that the valve is open and that the filter is blocked and requires cleaning. In one embodiment, the outlet chamber (22) contains a source (19) of ultra-violet radiation to which the flow of water is exposed, regardless of whether the valve (28,29) is in the open or closed condition.

Abstract: A low cost air filter restriction indicator gauge for use in conjunction with an internal combustion engine can be achieved by both simplifying individual part configuration and reducing overall part count. More specifically, a simplified design can be achieved by utilizing a one piece base cap which includes a locking extension and reset button integral therewith. By having this part injection moldable, it is easy to fabricate and lower in cost as a complex locking pin assembly can be eliminated. Further, the low cost device can be further enhanced by providing a two color visual indicator which displays one color when the device is in its reset position and a second color when the device is in its locked or set position.

Abstract: A two stage air filter restriction indicating device communicates with the supply of air passing from an air filter to the air intake of an engine. The amount of vacuum required by the engine to supply air is directly indicative of the amount of blockage in the air filtering system. The gauge or air filter restriction indicating device monitors this vacuum level and provides signals at an output indicating whether a predetermined vacuum level has been achieved. In one configuration, the gauge locks into this configuration and maintains its output, even when the engine is shut off. Alternatively, the gauge of the present invention automatically resets, thus not requiring a manual reset of the gauge.

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: An air filter cleanness gauge is provided. The gauge in a preferred embodiment includes a transparent cover. The housing has a first opening for fluid communication with the atmosphere and a second opening having fluid communication with a fluid source exposed to a filter. A vane is pivotally connected within the housing and provides a pressure boundary between the first and second openings. Movement of the vane indicates a change in pressure differential between the atmosphere and the fluid source, thereby indicating a need to change the air filter.

Abstract: A restriction indicator for an air cleaner of an internal combustion engine. A bellows-type diaphragm is biased toward a retracted position by a first end of a compression spring. A calibration wheel threadingly engaging the housing supports a second end of the compression spring, such that the restriction indicator can be calibrated by rotation of the calibration wheel. An end of the compression spring is seated on a slanted seating surface so that a plunger is pushed off-center to engage a latch and lock the restriction indicator.

Abstract: A simple, mechanical device is provided which produces an acoustic signal a specified depth. The device consists of a shear plug in an exterior wall of the device housing which prevents the movement of a spring biased piston. The plug is subjected to increasing differential pressure between the exterior and interior of the housing as the depth of the device beneath the water surface increases. At a known pressure differential, corresponding to a specified depth, the shear plug fails, allowing for the actuation of the piston. The spring biased piston strikes against a ledge in the device, creating the acoustic signal.