Abstract: An apparatus for notifying a user when the gas pressure of a gas is at or below a threshold pressure. The gas can be injected into a chamber of an incubator. The gas pressure can be measured, relayed and compared to the threshold pressure. If the gas pressure is at or below the threshold pressure, the user will be notified that the gas pressure needs to be corrected.

Abstract: A system and method for advanced warning of severe weather for general aviation aircraft is presented. An aircraft includes an onboard weather tracker which monitors atmospheric condition changes. The weather tracker uses data from an onboard barometric altimeter and a GPS device to calculate air pressure changes in order to identify when the aircraft is flying into a low-pressure zone. The weather tracker uses the air pressure's rate of change and the aircraft's speed to determine the criticality of a situation and appropriately notifies a pilot. The weather tracker provides the pilot with local airport information and alternative flight pattern information per the pilot's request.

Abstract: A low pressure alarm assembly where a switch for activating a low pressure alarm is operably associated with a link assembly which is operably actuable in response to the movement of a pressure responsive element. In one embodiment, the link assembly incorporates a pointer which is adapted to sweep across the plate of a pressure gauge into contact with the switch to close the switch and activate the low pressure alarm.

Abstract: A hydraulic circuit comprises a first and a second merging line capable of supplying pressure oil from a third pump for a third circuit to directional control valves in a first and a second circuit, respectively, and a merging valve for selectively communicating or cutting off the first and the second merging line with or from the third pump. The merging valve has a first shift position at which the third pump is connected to the second merging line, and a second shift position at which the third pump is connected to the first and the second merging line. The merging valve is shifted continuously between the shift positions. The hydraulic circuit can efficiently distribute pressure oil supplied from the third pump to the first and/or second circuit as well, and can prevent lowering of the operability of each of actuators connected to the first or second circuit.

Abstract: A gas supplying apparatus of a system for fabricating semiconductor devices is tested for clogs. The gas supplying apparatus includes a carrier gas supplying device for supplying at least one carrier gas, and a plurality of reactive gas supplying devices connected in parallel to the carrier gas supplying device. The reactive gas supplying devices gasify the reactive gas carried by the carrier gas. A wafer, on which a desired layer is to be formed, is situated in a process chamber into which the reactive gas is supplied from the reactive gas supplying devices. The gas supplying apparatus also includes pressure detecing devices for detecting the pressure of the carrier gas near each of the reactive gas supplying devices. The carrier gas is supplied under a predetermined pressure to the reactive gas supplying devices. The reactive gas supplying device to be tested for clogs is rendered operational while the other reactive gas supplying devices are shut down.

Abstract: A pressure sensor has a diaphragm that is exposed to air in a tire of a vehicle. A transmitter wirelessly transmits data representing the air pressure of the tire. A casing accommodates the transmitter and the pressure sensor. A lid closes an opening of the casing. A metal body is provided on the lid. When the opening of the casing is closed with the lid, the diaphragm is covered with the metal body.

Abstract: A method and apparatus for providing a cab pressure drop warning to an off-road machine operator and instructions for increasing the cab pressure and for providing incentive to correct the pressure drop, the method including comparing ambient and cab pressures and threshold pressure (i.e., the ambient plus a differential value), causing a vehicle operation disruption for at least a short period during which the operator may elect to remedy the cab pressure drop.

Abstract: A system (10) controlling operation of a steam turbine (T). Sensors (12) measure dynamic pressure level variations in a stage (S1-Sn) of the turbine. A signal (Ps) from a sensor is converted to a frequency based signal (Fs). A comparator (16) compares the pressure levels at various frequencies as represented by the frequency based signal (Fs) to a matrix of limiting values including both alarm and trip signal limits. The control system provides an alarm to an operator of the steam turbine if the comparison indicates that an alarm limit has been exceeded, or takes the steam turbine off line, if a trip signal limit has been exceeded. This is done to prevent damage to the steam turbine. However, the control system maintains the steam turbine in operation if no aeromechanical disturbances or instabilities, as sensed by the sensors, has occurred.

Abstract: An identification apparatus and method comprising an array of retractable pins in association with a housing attached to a base component through which each pin individually passes. The apparatus is attached to a primary device and in communication therewith. Each retractable pin is in individual physical contact with tension springs positioned below the pin and located in a containment sleeve within the housing. Each spring continuously exerts pressure on the base of their respective pins so as to push the pin up through the base component. At the base of each spring is a pressure sensitive pad in communication with the primary device.

Abstract: The present invention is directed to a filter module that may incorporate sensors to measure various characteristics of fluid flow and filtration. The sensors may be MEMS and may measure the temperature, flow rate, pressure, etc. of the fluid. Sensor measurements may be used to determine the occurrence of harmful events, such as cavitation or particle breakthrough, or to predict the remaining service life of a filter element.

Abstract: A tubing installation checking device is provided for determining proper installation of a tubing along a tube receiving channel in a peristaltic pump of the type having a tube receiving channel and a door for holding a tubing therein. The tubing installation checking device includes a pressure sensor held in the peristaltic pump positioned along the tube receiving channel downstream from the pumping mechanism for sensing pressure in the tubing and for providing a signal representing the sensed pressure. A valve is provided held in the peristaltic pump along the tube receiving channel downstream from the pressure sensor for closing the tubing when it is installed in the tube receiving channel.

Abstract: A system is disclosed comprising a flexible tube attached to a reservoir containing a hazardous material neutralizing substance, and possibly pressurized with air or another gas. The tube is routed around the perimeter of a region where one or more hazardous material containers are stored. In the event of a leak that spreads to the perimeter of the tube, the tube material type is so selected to degrade structurally in response to contact with the hazardous material, thereby rupturing and releasing the neutralizing substance stored within the tube and attached reservoir. The neutralizing material used is selected to neutralize the hazardous material released, to mitigate further damage or eliminate the hazard completely, or at least until intervening personnel can arrive.

Abstract: A high-diagnostic, dual sensor pressure switch having a one-out-of-two voting architecture useful in commercial and industrial fluid transport systems is provided for determining whether process connections and isolation valves are plugged or closed, and whether pressure sensors are deformed, corroded or otherwise compromised. The dual pressure sensors functionally employ similar electronic technology, and are each disposed to provide variable electrical outputs to one of a plurality of discrete A/D converters. The dual pressure sensors' electrical outputs are compared prior to the A/D conversion process in order to immediately identify large pressure deviations between the sensors. Each of the A/D converters' digital signals are routed to one of a plurality of independent CPUs or data processors; the CPUs then generate digital output signals representing either a logical 0 (Low) or 1 (High).

Abstract: A device for monitoring the filling of a bag (10) comprises a resistor element to be mounted on the outside surface of the bag, the resistor element being a flexible potentiometer (20), the resistance whereof being changed by bending of the potentiometer due to increasing bulging of the bag wall under continuing filling of the bag. The flexible potentiometer can be connected to an alarm device (24) reacting at a predetermined resistance value of the resistor element.

Abstract: What is disclosed herein is an identification apparatus and method comprising an array of retractable pins in association with a housing attached to a base component through which each pin individually passes. The apparatus is attached to a primary device and in communication therewith. Each retractable pin is in individual physical contact with spring tension means positioned below the pin and located in a containment sleeve within the housing. Each spring continuously exerts pressure on the base of their respective pins so as to push the pin up through the base component. At the base of each spring is a pressure sensitive pad in communication with the primary device.

Abstract: A system utilizing a two-circuit vacuum switch to monitor suction in the fuel system between the fuel selector valve and the engine-driven pump and warn the pilot of a restriction in the system or that the fuel tank from which the engine is feeding is exhausted of fuel.

Abstract: An apparatus for notifying a user when the gas pressure of a gas is at or below a threshold pressure. The gas can be injected into a chamber of an incubator. The gas pressure can be measured, relayed and compared to the threshold pressure. If the gas pressure is at or below the threshold pressure, the user will be notified that the gas pressure needs to be corrected.

Abstract: A method for controlled proportioning of liguids with a postive-displacement device (2) for dislocating a gas cushion (17) includes measuring the pressure (pab) in the gas cushion (17) at the time of a complete discharge of a liquid volume, measuring the discharge time (tab) for a complete discharge of the liquid volume and determining the time demand (&Dgr;t) to compress the gas cushion (17) by the postive-displacement device by means of the pressure (pab), the dead volume (Vo) of the gas cushion (17), a gas condition equation, and the volumetric gas flow (Q) discharged by the postive-displacement device. A corrected discharge time (toab) is determined as a proportioning control magnitude by a deduction of the time demand (&Dgr;t) from the measured dischage time (tab) with outputting, and/or saving, and/or resorting to the deviation of the corrected discharge time (toab) from a desired discharge time (tsoll) for regulating the discharge of the liquid volume.

Abstract: An apparatus for determining hydraulic pressure within a pressure sensing fluid filter assembly includes a pressure-sensing polymer thick film transducer associated with an oil filter assembly. Preferably, pressure sensors are provided on both the oil inlet and outlet areas of the filter. The pressure-sensing transducers send signals to a control module, which may compare pressure readouts at the inlet and outlet sides of the filter. Based on the pressure in the filter, the on-board sensing system will detect a clogged filter condition, and if necessary, the control module will send a signal to an in-dash display terminal, to indicate that an oil change is needed.

Abstract: An apparatus and methodology for continuously monitoring a statically pressurized piping system and providing an alarm signal if the system pressure integrity is compromised. The specific application considered is to monitor installed plumbing systems which are not in service or filled with water. Immediate detection of damage to these systems provides significant benefits to the user. The invention comprises a manifold with a means for sensing system pressure and provides an alarm signal if pressure falls below a pre-determined lower limit. The disclosed methodology suggests that a drop in system pressure is related to piping damage or leak that must be repaired. Once the source of the leak is located and repaired, the invention may be reset to provide additional monitoring.

Abstract: A low pressure alarm assembly where a switch for activating a low pressure alarm is operably associated with a link assembly which is operably actuable in response to the movement of a pressure responsive element. In one embodiment, the link assembly incorporates a pointer which is adapted to sweep across the plate of a pressure gauge into contact with the switch to close the switch and activate the low pressure alarm.

Abstract: A mechanical gauge having a mechanism for setting multiple alarms within tolerance values. When such tolerance values defined by the mechanism are reached, the same mechanism activates an alarm.

Abstract: A pressure sensor 1′ comprising a housing 10′ having a pressure introduction hole 12, a pressure sensing element 22 composed of a semiconductor element having piezoresistance effect, a holder 30 having fixed thereto the pressure sensing element 22, a guide member 98, a seal member 99 and a connector case 70, the pressure sensor element 22 and holder 30 joined in airtight manner to create a reference pressure chamber 72. On the holder 30 of the pressure sensor body is mounted a circuit board 40 having electrode pads, the electrode pads connected to connectors 80 fixed to the connector case 70 via conductive spring bodies 50. The guide member 98 supports holder 30, and in the opening 100 of the guide member 98 is placed the seal member 99.

Abstract: A method and system for locally sealing a vacuum microcavity, methods and systems for monitoring and controlling pressure in the microcavity and method and system for trimming resonant frequency of a microstructure in the microcavity are provided. The microcavity has an initial base pressure therein after the microcavity is locally sealed at an access passageway. The monitoring and control methods include measuring pressure in the microcavity and providing a signal when the pressure exceeds a maximum desired level. The control method also includes reducing the pressure in the microcavity to a pressure at or below the maximum desired level in response to the signal to compensate for vacuum degradation within the vacuum microcavity.

Abstract: A device for providing a plurality of indications of a select pressure, said device including: an electronic interface having an input and an output; a resistive structure adapted to measure the select pressure and being electrically coupled to the input of the electronic interface; a first output for providing a signal indicative of the select pressure, the first output being electrically coupled to the output of the electronic interface; and, a comparator coupled to the output of the electronic interface and being adapted to provide a signal indicative of whether the select pressure is greater than a predetermined threshold.

Abstract: A method for determining the depth (DL) of a fluid contact level between a first fluid (F1), such as water, and a second fluid (F2), such as crude oil or natural gas, within the pores of an oil and/or gas bearing formation surrounding a borehole comprises measuring the phase pressure PF1 and PF2 of said pore fluids using a pressure probe assembly which is lowered to a depth (DP) above the depth of said contact level (DL) and determining the depth of said interface on the basis of the equation: D P - D L = P F1 - P F2 g ⁡ ( ρ F1 - ρ F2 )

Abstract: An apparatus for determining hydraulic pressure within a pressure sensing fluid filter assembly includes a pressure-sensing polymer thick film transducer associated with an oil filter assembly. Preferably, pressure sensors are provided on both the oil intlet and outlet areas of the filter. The pressure-sensing transducers send signals to a control module, which may compare pressure readouts at the inlet and outlet sides of the filter. Based on the pressure in the filter, the on-board sensing system will detect a clogged filter condition, and if necessary, the control module will send a signal to an in-dash display terminal, to indicate that an oil change is needed.

Abstract: A diaphragm-type tire pressure indicator is fixedly fastened to the air nozzle of a vehicle tire for indicating a low pressure of the tire. A flexible diaphragm is mounted in a receiving chamber in the casing of the tire pressure indicator. A push rod is connected to the flexible diaphragm for being moved up and down with the diaphragm subject to the status of the tire pressure of the vehicle tire. A sleeve is mounted in the receiving chamber and is around the push rod. A spring is sleeved onto the push rod.

Abstract: A method and apparatus for detecting a restricted or bypassed transmission oil filter by providing pressure transducers on both sides of the oil filter whereby the pressure differential will indicate the extent of filter restriction. A first alarm is activated at a first pressure differential to indicate a restricted filter and the need for filter replacement. A second, higher level, alarm is activated to indicate the filter is bypassed and the engine is reduced in speed to allow the pressure and the pressure differential to drop to the point that the filter is no longer bypassed. This enables the vehicle to be operated with limited capabilities to allow the vehicle to be driven to the shop for filter replacement. If the lowered engine speed is insufficient to reduce the pressure differential to stop the bypass, then the engine speed is further reduced to a low idle and the transmission shifted to neutral.

Abstract: This is a tire pressure warning system that can be easily installed as an after-market item. The alarm can easily be heard while the vehicle is underway. The shatterproof window of the pressure gauge exposed at the center of the wheel cover enables the driver to quickly check pressure. An adjusting screw on the pressure gauge selects the pressure at which the alarm will sound.

Abstract: A leak detection device for double-wall pipeline or container systems has a leak detector with a vacuum pump, a pressure-dependent switch for the vacuum pump, and an alarm device. The leak detector monitors simultaneously several containers. A collecting main is connected to the vacuum pump and by vacuum lines to the containers. Each container has a vacuum connector connected to a control space of the container. The control spaces are parallel connected to the leak detector. Each vacuum line has a first liquid lock arranged at the vacuum connector so as to block liquid that has leaked into the vacuum lines from a leaky container from penetrating into the control spaces of the leak-free containers. A second liquid lock is arranged in the collecting main to prevent liquid from entering the vacuum pump. A measuring line taps the collecting main and is connected to the leak detector.

Abstract: The invention relates to a heavy goods vehicle, specially for the transportation of slag, comprising a loading platform for vessels containing slag, fitted with a gripper device for receiving and moving a standardized load-bearing implement which can be actuated by a hydraulic cylinder (11) and an anti-tilt device (15) for the vehicle which operates during movement of the load-bearing implement. The vehicle is also fitted with at least one hydraulic cylinder (11) with switches. Upon a given stroke of the piston, at least one switch engages a device detecting hydraulic pressure inside the cylinder on one or both sides of the piston. The pressure detection device triggers a security device, e.g. a display for the driver or an operation blocking device.

Abstract: Acoustic level sensing by creating, or failing to create, resonance in a tube having a free end. An acoustic transducer at one end of the tube injects sound at a frequency that could produce resonance, depending on whether the free end is open or closed. The drive to the acoustic transducer is then removed, and the sound decay in the tube is monitored to determine if resonance occurred. Based on that determination, a signal is produced that indicates whether a material has or has not closed the free end of the tube. Beneficially, the same acoustic transducer that produces the sound monitors the sound decay. To determine whether resonance has occurred, or to verify system operation, the sound decay at the possible resonant frequency can be compared to the decay at another frequency. Temperature compensation can be performed by attempting to produce resonance at a plurality of frequencies.

Abstract: A device for degerminating water passing through a sanitary appliance subjects water flowing through a housing and a filtering device in the housing, to radiation, thereby destroying the micro-organisms in the water and/or the filtering device. An energy supply circuit 10 for a UV lamp is controlled by an electronic control unit which receives a “switch-on” signal produced as follows: when a manually-operated valve 4 in a fresh water supply is opened, pressure on a pressure sensor 5 falls; a magnetic valve 6 initially remaining closed. A corresponding electrical signal is then sent to the electronic control unit, which activates the energy supply circuit and opens the magnetic valve 6 in a set time sequence. When the manually-operated valve 4 is closed, the pressure on the pressure sensor 5 rises. The corresponding electrical signal is then sent to the electronic control unit, which in turn deactivates the energy supply circuit according to certain time factors.

Abstract: A low battery detection circuit is disclosed for detecting low battery voltages in hearing aids and other battery operated devices. The low battery detection circuit operates reliably on a small amount of current, which does not significantly increase overall battery drain. An output signal is generated whose amplitude and frequency increase as battery voltage decreases below a predetermined level. The circuit's minimal number of components and output signal characteristics make it particularly applicable as a low battery early warning device for hearing aid devices.

Abstract: Apparatus and method for correctly detecting the level of a processing liquid such as HPM in a processing tank in the event that any drift occurs in a detector is disclosed. A liquid level detecting apparatus (70) comprises a pressure sensor (73) operable to generate an output signal S0 which is maintained at a constant signal level until the level of HPM reaches a predetermined position M in the tank and rises in the signal level as the liquid level rises in the tank after reaching the predetermined position M, a determination circuit (93) for determining whether the liquid level reaches the predetermined position M and a liquid level detecting circuit (94) for detecting the liquid level. The output signal S0 from the pressure sensor is input to an amplifier (92). The liquid level detecting circuit (94) comprises a low-pass filter (97) which receives the amplified signal and generates an output pressure signal S4.

Abstract: An infrasonic pressure wave sensor apparatus is provided to detect infrasonic pressure waves generated by such means as an air-burst detonation. The infrasonic pressure wave sensor comprises a Doppler transceiver utilizing a microwave emitting device, such as a Gunn diode, and a microwave receiving device, such as a receiver diode. The infrasonic pressure wave sensor also comprises a reflective diaphragm, such as a conductive rubber or conductive plastic diaphragm. The microwave emitting device and microwave receiving device cooperate to measure the deflections in the reflective diaphragm as the reflective diaphragm is exposed to infrasonic pressure waves. The infrasonic pressure wave sensor yields a 2 V signal while remains extremely sensitive to pressure waves having a frequency of less than 1 Hz.

Abstract: Apparatus for performing diagnostics through a regulator is disclosed. The pressure regulator is disposed in a fluid flow passage and has a throttling element moveable in the flow passage. A stem is attached to the throttling element. The apparatus includes a first pressure sensor for measuring pressure upstream of the throttling element, a second pressure sensor for measuring pressure downstream of the throttling element, and a travel sensor for detecting the position of the throttling element. A processor is provided which includes a stored algorithm for determining flow rate based on the measured pressure and travel values, and an alarm routine for generating logic alarms based on the measured operating parameters.

Abstract: A device for providing a plurality of indications of a select pressure, said device including: an electronic interface having an input and an output; a resistive structure adapted to measure the select pressure and being electrically coupled to the input of the electronic interface; a first output for providing a signal indicative of the select pressure, the first output being electrically coupled to the output of the electronic interface; and, a comparator coupled to the output of the electronic interface and being adapted to provide a signal indicative of whether the select pressure is greater than a predetermined threshold.

Abstract: A system for remotely managing a network of waste containers (12), each of which is associated with a monitoring unit (38), utilizes a central computer (50) having a communication link to each monitoring unit (38). The central computer (50) provides a dynamically updated display, via a display module (60) having a full container window (or zone) which shows full containers (12), an alarm window (or zone) which shows non-full containers (12) having an alarm condition, and a container status window (or zone) which shows non-full containers not having an alarm condition.

Abstract: An electronic system with a control box. Pressure sensors are coupled to the electrical lines to determine and display pressure. Flow metering devices are coupled to the electrical ines to determine and display the flow rate. Liquid bridging sensors include four liquid bridging sensors in four sites with a valve actuated by electro-mechanical means. The valve located within the water line with a voice-auto dialer allowing data from the system to be transferred via a phone line. An electrical circuit includes a port for coupling with a conventional central computer and has computing software allowing the storing of the rate of flow of water. An internet program is adapted to notify the user and authorities upon emergency shut-off and provide the pressure and flow rates of the water lines and if the liquid bridging sensors have detected leaks. Finally included is control software to program and shut off the water supply.

Abstract: A microcontroller establishes normal operation and vacuuming operation profiles of time and vacuum for a pool or spa circulating pump. A user slightly adjusts the levels of vacuum within a predetermined range for storing a vacuum profile envelope within the memory for a normal pump circulating operation and a vacuum profile envelope within the memory for a vacuuming operation. A comparator compares actual inputs of time-from-start and pump vacuum with the normal operation envelope during normal operation of the circulating pump. The comparator compares real time inputs of the sensed vacuum and the time-from-start when the controller is in the vacuuming mode with the vacuuming envelope stored in the memory. Deviations of the sensed pressures from the envelope cause pump shutdown and alarm activation. A calibration switch is positioned inside a locked weatherproof control enclosure.

Abstract: Methods are disclosed for collecting sensor data in a pressure regulator system including a controller and a plurality of sensors. The controller and each of the individual sensors are activated as required to collect sensor data during a sampling period thereby reducing the amount of power consumed by the pressure regulator system. Further power conservation measures are implemented by using a battery sensor to monitor the capacity of the pressure regulator battery and placing the pressure regulator in reduced power consumption operating modes as the capacity of the battery is reduced.

Abstract: A warning device configured for removable mounting in combination with a high pressure gas cylinder and a regulator used to regulate the high pressure gas supplied by the cylinder. The device compression mounts between the regulator and tank outlet on conventional portable oxygen and gas supply systems using a specially configured manifold. The device features one or a combination of alarms, from a group including audio, visual, electronic, and remotely transmitted alarms. These alarms are activated by a pressure switch monitoring the remaining supply in the gas cylinder through a conduit the manifold. The alarm signal from the device alerts the user, or a third party monitoring the user, of current tank pressure or will sound an alarm when remaining high pressure gas inside the gas cylinder drops below a predetermined level.

Abstract: A portable fire extinguisher assembly includes a fire extinguisher with a tank containing fire extinguishing material, a valve for metering release of the fire extinguishing material, and a gauge displaying pressure within the tank, and a docking station in communication with the fire extinguisher. An electronic circuit in communication with the fire extinguisher and the docking station issues a signal upon detection of predetermined conditions, including at least one predetermined internal condition and at least one predetermined external condition.

Abstract: A system which allows the firefighter to monitor a variety of safety related parameters during firefighting activities through audible and/or visual means. The system of the present invention monitors the pressure in the firefighter's breathing system and also monitors ambient temperature and motion of the firefighter. An audible alarm is activated to indicate a potential emergency situation relating to low remaining air time, impending thermal breakthrough or lack of motion of the firefighter.

Abstract: A portable fire extinguisher assembly includes a fire extinguisher with a tank containing fire extinguishing material, a valve for metering release of the fire extinguishing material, and a gauge displaying pressure within the tank, and a docking station in communication with the fire extinguisher. An electronic circuit in communication with the fire extinguisher and the docking station issues a signal upon detection of predetermined conditions, including at least one predetermined intenal condition and at least one predetermined external condition. The fire extinguisher electronic circuit includes cooperative male and female electrical/communication connection elements defined by the fire extinguisher and docking station.

Abstract: Seat Operated Switch and Warning System with an air cushion, an air tube leading from the air cushion to an air pressure switch, an electronic circuit to activate devices when a reduction in air pressure is sensed, a digital recordable message device, a radio frequency transmitting device, a housing to contain the pressure switch, digital message device and transmitting device, a matching radio frequency receiving device, and a portable housing to contain said receiving device said housing also containing an audio transducer that creates an audible warning sound activated by said receiving device. A preferred embodiment includes wherein when a person sits on said air cushion the pressure caused by the weight of the person causes said air pressure switch not to activate, but when said person exits off of said air cushion said air pressure switch causes said recorded message to play and causes said transmitter to send a signal to said receiver causing said audio transducer to produce a warning sound.

Abstract: A seat belt warning device includes a sitting detection switch which is adapted to be in an on-state when a person sits on a vehicle seat and in an off-state when a person is not sitting on the vehicle seat, and a fastening detection switch which is connected to the sitting detection switch in series and adapted to be in an on-state when a seat belt is not fastened and in an off-state when the seat belt is fastened. A warning member is connected to the sitting detection switch and the fastening detection switch in series and is supplied with electric current in the on-state of the sitting detection switch and the on-state of the fastening detection switch to issue a warning.

Abstract: An indicator assembly includes a conduit segment located in place along a gas supply line served by a pressurized tank. A pressure actuated switch of the assembly closes upon sensing gas pressure in the conduit segment to close a circuit including a battery and an indicator to signal a user that the supply line is pressurized which can occur when proper shut down procedure is not accomplished or a faulty control valve. A bleed valve on the conduit segment permits venting of a pressurized gas line. A check valve of the assembly prevents erroneous activation of the indicator by residual gas trapped in the supply line after shut down.