Abstract: An apparatus for monitoring the vacuum of a vacuum switch having at least one vacuum switch tube with a switch chamber and switch contacts is provided. The apparatus has a remotely interrogatable pressure measurement sensor in the form of a piezocrystal or surface acoustic (SAW) device arranged in the interior of the vacuum switch tube and a remote interrogation device placed external to the vacuum switch for monitoring the vacuum via the sensor.

Abstract: A signal generating pressure gauge includes a pressure indicating unit having a housing provided with an inlet, a pressure-value indicating panel, a pressure converting unit fluidly communicated with the inlet and provided with a rotary shaft which rotates in response to pressure entering into the inlet, a pointer which rotates with the rotary shaft in order to indicate on the indicating panel the pressure imposed on the inlet, and an electrically conductive pressure control needle movable together with the pointer. An adjustable pressure-setting mechanism includes a rotary plate rotatably mounted in the housing and rotatable relative to the indicating panel, and electrically conductive low-pressure and high-pressure stop units which extend into a setting hole unit in the rotary plate. The positions of the low-pressure and high-pressure stop units in the setting hole unit are adjustable and correspond to the lower and upper limits of a desired pressure range.

Abstract: An alarm system for a particular type of lifting seal type valve, such as those employed in pressure relief. The alarm system consists of a signal source, an alarm mechanism and a signal carrying conductor secured to a seated lifting seal valve in such a manner that valve actuation will disrupt the transmission, interrupting the signal and activating the alarm.

Abstract: Electrical circuitry associated with a pneumatic pressure detector for use in an overheat condition or fire alarm system for aircraft. The pressure detector comprises a plenum situated between a pair of deformable diaphragms and pressurized by a capillary type sensor containing an absorbed gas. A control electronics stage is located remotely from the pressure detector stage and is connected thereto by a single wire extending between them. The control electronics stage senses integrity failure of the pressure detector, an overheat or fire condition, and a ground fault in the connection between the two stages and provides corresponding output indications. The circuitry also includes ground connections at the control electronics stage and the pressure detector, respectively.

Abstract: Insulating oil in electric power transmission devices such as a transformer is filtered for removal of accumulated water and carbon particles. The filter and circulation pump are usually located in a separate cabinet external to the transformer with circulation conduits connecting the filter, the pump and the transformer. To prevent or minimize environmental contamination by leaks or ruptures in the oil circulation conduits, oil flow within the pump suction conduit is monitored independently of oil pressure within the pump discharge conduit. A flow rate or discharge pressure below a predetermined minimum operates motor control relays to terminate the pump drive motor operation and transmit appropriate alarms. Additionally, an accumulation of oil in the dry sump volume of a pump and filter housing also activates motor terminating relays and transmits an alarm.

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 differential pressure sensor is attached to a process via a high and a low pressure impulse line. An absolute pressure sensor is also attached to each impulse line. To determine if an impulse line is blocked, a noise signal is acquired from the corresponding absolute pressure sensor. A variance of the noise signal is determined and compared to a threshold. If the variance is less than the threshold, an impulse line blockage is indicated.

Abstract: A residual pressure sensor for verifying that a residual pressure is zero, and to a monitoring apparatus for monitoring for faults in the residual pressure sensor. In order to detect that a residual pressure has completely gone, the residual pressure sensor detects change conditions in the output therefrom, and an output for no residual pressure is not generated while there are changes. Moreover, an electrical power supply condition to a drive solenoid (21) of a solenoid valve for opening/closing a pressure supply line, is monitored using a fail-safe current sensor (21) which outputs a logic value "0" when the presence of a current is detected, and which outputs a logic value "1" when the presence of a current is not detected. Fault monitoring of the residual pressure sensor is then carried out based on the monitoring output conditions of the current sensor and the output conditions of the residual pressure sensor.

Abstract: A device and method for detecting a containment failure. The device has a gas supply means (18) for providing a gas to a containment failure volume (16, 60) and for maintaining a constant gas pressure in the containment failure volume. The device also has gas flow monitoring means (26) for monitoring flow of the gas into the containment failure volume. The flow of gas into the containment failure volume is indicative of a containment failure.

Abstract: A pressure indicating device (30) for providing an indication of the pressure that existed within a fluid filled pressure vessel (22) just prior to depressurization of the pressure vessel. The device comprises: a housing (102); a piston (130) for temporarily sealing an open end of the housing and outwardly movable in response to a pressure differential not less than a predetermined level generated subsequent to the depressurization of the pressure vessel; and a sheer disk (150) including a first part (160) attached to an end of the piston and a second part (162) attached to an end of the housing (102).

Abstract: A sensor body has an orifice forming a central fluid flow passage therethrough and supports a thin conducting frangible rod, such as graphite, across the central fluid flow passage. The graphite rod and connectors are insulated from the body when the body is made from a conducting material such as metal. When the graphite rod is broken by fluid flow, a circuit is broken and an alarm condition is created.

Abstract: On method of sensing a ventilation failure measures a ventilation cycle and if the pressure is not maintained throughout the whole of an inspiration period above the setting for the low datum point 10 an alarm is signaled. A normal ventilation cycle is shown in FIG. 1(a) with the pressure over the ventilation cycle indicated by curve 14, low pressure datum 10 and the high pressure datum 12. The inspiration period 16 occurs for a given length of the cycle 14. When the tube feeding air to the patient is disconnected (whether wholly or partially) the ventilation cycle is as shown in FIG. 1(b). Inspiration peak 18 is now much lower and pressure drops rapidly, once the given volume has been delivered, from peak 18 to below set low pressure datum 10 (before termination of period 16). The peak 18 and the slope of the curve as indicated at 20 will vary depending upon the circumstances experienced. Another method measures the period between excursions of the pressure above a given level above datum 10.

Abstract: A pressure sensor assembly includes a disk entirely of metal and having a plurality of circumferentially spaced petals, separated by a plurality of radially extending slots. The slots extend from the periphery of the disk to a position near the center. However, the disks are in electrical communication with one another. A pair of wire leads are respectively placed at terminals on two separate spaced-apart disks with the opposite end portion of the leads connected to an alarm monitor. The disk body can be used in low or high temperature applications and is corrosion resistant and preferably entirely metallic (for example, stainless steel). The disk body is designed to be installed between standard pipe flanges, between a flange and a rupture disk holder, or in a holder that is used as, or located downstream of, a rupture disk or similar device. The device is designed to cause a discontinuity (open circuit) in an electrical circuit as a result of fluid flow through the pipe.

Abstract: The invention is directed to a pressure monitoring system for monitoring a hydraulic pressure which is supplied from a fluid pump and accumulated in an accumulator. The pressure monitoring system includes an electric motor which drives the fluid pump to supply the hydraulic pressure in substantially linear proportion to a current fed to the motor, a current detection device which detects the current fed to the motor, and a pressure estimation device which estimates the hydraulic pressure accumulated in the accumulator in response to the current detected by the current detection device. A malfunction detection device may be provided for detecting a malfunction on the basis of the output of the pressure estimation device.

Abstract: An alarm system as a support of an elevated floor, whose plurality of pressure sensing devices are installed as a support outside the floor of the protection area, wherein a pressure sensing device comprises: a cover in direct contact with the lower side of the floor; a vessel, mounted below the cover, having a basin in its middle below the cover, to be filled with liquid, the basin of the vessel having a hole, through which the liquid can flow; a seal, inserted between the cover and said vessel along the circumference of the basin to impermeably seal the basin, said cover and said vessel being not in contact with each other to leave a gap for the cover to move down; an elastic membrane, which is mounted tightly on the vessel at the place of the opening of the hole; and a sensor, which is in contact with the elastic membrane to sense the deformation of this membrane under the pressure of said liquid; whereat, when an external weight exerts pressure on the floor, the cover, having undergone pressure, in turn p

Abstract: A pressure sensor for an apparatus for controlling and maintaining air pressure in vehicle tires. The vehicle compressor outlet is connected through individual pneumatic tire circuits to each vehicle tire, via rotary couplings in the associated axles. Each tire circuit includes tubing for carrying air and monitoring tire pressure, the circuits supporting pressure sensors and electrovalves housed in a control unit in the dashboard of the vehicle. The sensor includes a piston which causes a shutter to move in and out of the light path of a LED/phototransistor device. When the sensor signals low tire pressure via a an electronic circuit, the corresponding electrovalve is energized for the compressor to pump the tire up back to its set pressure. The sensor further includes means for varying the set point.

Abstract: A method of and a system for electrically processing vacuum pressure information, which is suitable for use in a vacuum unit. Pressure values are detected and a desired pressure value lower than the highest vacuum pressure value of the detected pressure values is displayed on a displaying device in digital form. The desired pressure value is stored in a storing device. Each of pressure values relative to vacuum, which are detected by a pressure detecting element held in front of a passage communicating with a vacuum port, is converted into a digital signal. The so-converted digital signal is digitally displayed on the displaying device. The desired pressure value stored in the storing device is compared with each of the detected pressure values relative to the vacuum, and information about faulty points is displayed on the displaying device based on the result of comparison.

Abstract: A fluid flow monitor has coaxial conductive annular supports separated by an insulating gasket and connected by a conductive member. One support has a lesser external diameter and a smaller internal diameter than the other to reduce the chance of accidental short circuiting. Wires are attached to each support, a third wire supplies a floating ground to ensure monitor tripping is not caused by a ground fault. Tabs on the inner perimeter of the supports may mount the conductive member.

Abstract: A monitoring apparatus for monitoring the condition of a pressure relief rupture disk disposed in a pressure relief conduit is disclosed. The monitoring apparatus includes an electrically conductive rupture disk circuit, spaced apart electrodes affixed to the rupture disk, a rupture disk energizing circuit, a comparison circuit and an alarm circuit. The resistance between the electrodes changes when the disk ruptures. The energizing circuit includes a power source coupled to one of the electrodes. The magnitude of an output signal produced at the other of the two electrodes is dependent upon the resistance between the electrodes. The comparison circuit includes means for generating a selected magnitude output signal depending on the comparison of the magnitudes of the electrode output signal and an adjustable reference signal. The alarm circuit is electrically coupled to the comparison circuit and selectively activates an indicator alarm based on the magnitude of the comparison circuit output signal.

Abstract: A solid state temperature compensated annunciator is disclosed. The solid state temperature compensated annunciator includes a pressure sensor for measuring a pressure of the fillant within a vessel and a temperature sensor for measuring the temperature of the fillant within the vessel. The solid state temperature compensated annunciator determines a pressure that the vessel would have if the vessel were filled with a predetermined amount of fillant, and compares the measured pressure to the determined pressure. If the measured pressure is below the determined pressure, a warning signal is issued.

Abstract: A transparent housing for installation in a marine raw water line. The housing has an inlet chamber including a perforated plate disposed athwart the housing and comprising the downstream wall of the chamber. The plate permits water flow while acting to trap unwanted materials in the water stream. The transparent housing provides means for visual monitoring of the plate and of the interior of the inlet chamber. A sacrificial zinc pencil is disposed within the chamber to protect metal components and to provide a visual indication of the extent of electrolytic activity within the system. Debris in the sea water, for example, or from a broken pump impeller, or portions broken from the sacrificial anode, become trapped in the inlet chamber where they can be visually observed. In such cases, or when anode replacement is desired, the apparatus can be conveniently removed from service while appropriate changes are made.

Abstract: A liquid level sensing and monitoring system for a medical fluid infusion system has an IV spike with a pressure sensor which contacts fluid in an infusion container such as an IV bag or bottle. When an adequate amount of fluid is in the container, the resulting pressure on the sensor is at a relatively high level; however, when the fluid reservoir is nearly depleted, the pressure on the sensor falls to a low level, thereby activating the sensor and associated control circuitry which operates an alarm or warning indicator. In lieu of the pressure sensor, the device may use a resistive or capacitive sensor. When the liquid level falls below the electrical sensor, its state changes, and the alarm circuitry is activated.

Abstract: An abnormality detecting apparatus constantly monitors even a slight amount of gas which has leaked by checking a gas supply pipe when it is determined that the pressure regulating function of a pressure regulator is abnormal. The abnormality detecting apparatus detects an abnormality of the regulated pressure of a pressure regulator appropriately by comparing the regulated pressure with a predetermined low value of a pressure regulating range when the gas flow rate is high and with a predetermined high value of a pressure regulating range when the gas flow rate is low.

Abstract: A portable gas pressure monitor includes a pressure sensor which may be coupled to a pipeline tap downstream of a work area, and first and second comparator circuits receiving the signal from the pressure sensor and comparing the pressure signal with a low pressure set point and a high pressure set point. The two set points define a safe range for the pressure of the gas being monitored. If the sensed gas pressure falls below the low set point one audible signal is generated, and if the sensed pressure exceeds the high set point, a distinctly different audible signal is generated, thus immediately and unequivocally alerting operating personnel of the nature of any alarm. The pressure is also displayed for the operator.

Abstract: A pipetting apparatus is provided with clot detection. The pipetting apparatus comprises a nozzle for aspirating a sample. A pressure sensor is connected with the nozzle for measuring pressure in said nozzle. A plurality of pressure difference calculating circuits are operatively connected with the pressure sensor, each for inputting an output of said pressure sensor and obtaining a pressure difference at a different pressure calculation period, respectively. A plurality of discriminating circuits each having a different discrimination threshold value determined according to each of the pressure calculation periods are provided. An alarm circuit is included for outputting a clot detection alarm signal when at least one of said discriminating circuits discriminates that the obtained pressure difference exceeds the discrimination threshold value.

Abstract: An electronic water utility safety apparatus comprising a control box positionable within the house of a user. A display indicates a sensed water pressure. An indicator is mounted in the box to generate an audible signal upon the pressure being modified from an acceptable range. An electrical line is positioned from the box to a source of potential within the house. A second line is positioned from the box to a water line for the house. A sensor is mounted on the line to determine the pressure within the line and to allow the indicator to display such pressure read. A valve is located within the water line adjacent to the sensor to shut off the flow of water upon the pressure being outside of a predetermined range. An electrical circuit is provided for controlling the box.

Abstract: Refrigerant pressure in the condenser unit of a chiller is monitored relative to a real time alarm limit for the refrigerant pressure. The real time alarm limit is computed from time to time by a microprocessor. The value of the computed alarm limit will vary with the cooling load being experienced by the chiller's evaporator unit.

Abstract: A sensitive to a change in the physical dimension(s) of the exterior surface of a pressure vessel transducer and attached to the exterior surface thereof the pressure vessel may be a vacuum chamber. The transducer measures exterior dimension change, representing interior pressure change information, without intrusion. The measurements are displayed using distinctive lights or audible alarms which signal if the pressure inside the vessel is within a predetermined range. If the pressure within the vessel varies outside of the predetermined range, a more precise display device such as a meter, is provided to aid facility personnel in deciding when repairs are necessary.

Abstract: The invention relates to an electronic apparatus fastened on an oil transformer, which measures with precision, continuously and simultaneously the value of the temperature, of the level of the dielectric liquid contained in the transformer, of the pressure inside the transformer and of the current-strength at the transformer secondary. With this measure of the four parameters are associated the continuous memorization of these measures over 24 hours, the visualization of these memorized measures on the apparatus or at distance on a peripheral equipment connected to the apparatus as well as the control of an alarm system and of a stop system of the transformer for each parameter.

Abstract: A low air warning device for scuba divers. The low air warning device attaches to the first stage of the air regulator, which is attached to the top of the air tank. The low air warning device, being compact and easily used, sounds an audible alarm in the event of low air levels. The low air warning device utilizes a piezo speaker element and driver, located within the waterproof housing, to produce an audible tone which is easily heard under water. The low air warning device automatically turns itself on and off utilizing a water conductivity activation switch.

Abstract: A method and system are provided for monitoring the pressure of gas in a gas filled circuit breaker container based on a temperature compensated gas pressure signal which is compared with a signal representing a desired gas pressure in the container to provide a signal indicating a gas leak when the actual pressure is less than the desired pressure. In addition to identifying a gas leak, the method and system is operable to deactivate the circuit breaker when the actual pressure decreases below a predetermined low pressure, to determine the gas leak rate and to deactivate the circuit breaker if the leak rate is greater than a predetermined acceptable rate and, otherwise, to determine the time required for the pressure to decrease to the unacceptable low pressure, and to activate an alarm, visual display and/or recording of information in response to certain detected conditions with respect to the gas pressure.

Abstract: Apparatus and methods for monitoring a characteristic of fluid flow through a fluid dispenser that permit adverse flow conditions to be monitored, analyzed and displayed to an operator. The monitor samples either the static or firing pressure a predetermined number of times and calculates an average static and firing pressure over the sampling period. The average pressure values are compared to high and low warning and alarm limits and warning and alarm error codes are produced as a function thereof. In addition, individual sampled values are compared to the high and low warning and alarm limits and pressure values exceeding the limits during a sampling period are counted. Warning and alarm error codes are produced as a function of the counted values exceeding predetermined count values.

Abstract: A method and an apparatus for electrically processing vacuum pressure information in a vacuum unit. The apparatus basically comprises a vacuum supply mechanism, a detecting device, a determining device, a failure precognition signal generating device and a pressure setting-up device. In the apparatus, pressure values are first detected, and a desired pressure value lower than the maximum pressure value of the detected pressure values is digitally displayed on a display unit. Then, the desired pressure value is stored in a storage unit, and pressure values relative to vacuum, which are detected from the detecting device held in front of a passage which communicates with a vacuum port, are converted into digital signals. Thereafter, the digital signals thus converted are digitally displayed on the display unit. Further, the desired pressure value stored in the storage unit is compared with each of the detected pressure values.

Abstract: A wheelchair seating system preferably for use with an inflatable cushion device such as that incorporated herein by reference includes a base suitable for containing the components necessary to provide for either manual or automatic inflation and deflation of the lower cushion incorporated in the seating system and the upper cushion upon which a user sits.

Abstract: Apparatus for controlling and maintaining air pressure in vehicle tires. The vehicle compressor outlet is connected through individual pneumatic tire circuits to each vehicle tire, via rotary couplings in the associated axles. Each tire circuit includes tubing for carrying air and monitoring tire pressure, the circuits supporting pressure sensors and electrovalves housed in a control unit in the dashboard of the vehicle. The control unit also houses electronic circuits interfaced with the sensors and electrovalves. The sensor includes a piston which causes a shutter to move in and out of the light path of a LED/phototransistor device. When it signals low tire pressure to the electronic circuit, the corresponding electrovalve is energized for the compressor to pump the tire up back to its set pressure. A front panel has LEDs and gauges for the driver to keep tabs on events.

Abstract: A computerized diagnostic system includes a microprocessor-based electronic controller which controls a portable machine. Electronic sensors provide raw, operating parameters to a RAM type memory of the controller. A locator locates predetermined RAM addresses of raw machine operating parameters which are known to be useful in the monitoring and diagnosis of the portable machine. A remote, microprocessor-based computer diagnoses and monitors the electronically controlled machine. A display means displays the user friendly symbols in function-specific groupings which reveal patterns of machine operation, and which identifies the process which the machine is performing.

Abstract: A security barrier for placement across a passageway is made up of interconnected pressurized tubing made up in a grid pattern with openings too small to allow passage. The tubing is connected to a pressure switch, located away from the barrier site, which activates an alarm upon occurrence of a pressure drop. A reinforcing bar is located inside and along the length of the tubing so as to cause the tubing to rupture and set off the alarm upon an intruder's making an attempt to crimp and seal off a portion of the tubing by application of a hydraulic tool. Radial and rectangular grid patterns are disclosed.

Abstract: A diver's air tank pressure gauge having audible and visual alarms, an alarm pointer for indicating the pressure at which the alarms will activate, and a crank assembly for changing the position of the alarm pointer. The pressure gauge dial has a cutout for limiting the travel of the alarm pointer between acceptable high and low pressure limits. When the air tank pressure equals a preset alarm pressure, an electrical circuit is completed which activates the alarms. The diver can then turn off the alarms by resetting the alarm indicator to a lower pressure setting and continue the dive at a shallower depth.

Abstract: A simple, reliable, compact and inexpensive fluid pressure discontinuity analysis system includes a basic capacitive pressure transducer, made of two closely spaced insulating plates whose opposed faces contain conductive layers, and one of which plates is a flexible diaphragm of low mechanical hysteresis. The transducer is coupled to a variable pressure source which under normal operating conditions remains at a substantially constant pressure level. The output signal from the transducer has its high-frequency AC component attenuated by a low-pass filter, whose output in turn has its DC component substantially removed by capacitive blocking, after which the remaining AC output is then amplified by a circuit including an operational amplifier. This AC-amplified signal is then compared with a "reduced-magnitude average" reference signal (produced by an AC-to-DC conversion side-circuit followed by magnitude-level adjustment).

Abstract: The respective partial pressures of an inert gas in the tissues of a human body different in saturation half-time are calculated from the sensed ambient pressure during diving. The respective remaining times of the tissues up to the non-decompression limit are calculated from the obtained partial pressures of the inert gas and are displayed simultaneously on a graphic display.

Abstract: A self-contained sensing unit to be mounted on air duct between the filter and blower to monitor the condition of the filter. The sensor has a probe to be inserted into the duct downstream of the filter. The probe is in fluid communication with a bellows. When the filter becomes clogged, a negative pressure in the duct actuates the bellows which in turn closes a circuit from a battery to a signaling device.

Abstract: An apparatus for monitoring the condition of a pressure relief safety valve, which has a magnetic ball shiftable from a home position by fluid under pressure when the relief valve opens, and an adjacent sensor responsive to shifting of the ball to provide a signal representing an open valve.

Abstract: An integral burst sensing disk assembly wherein a disk forms an integral part of the burst sensing circuit. The improvement of the instant invention comprises using a rupture disk to form a complete circuit between a wire connected to the burst membrane portion of the disk, through the disk to another wire connected to the outer surface of the disk. When the disk bursts to relieve an over-pressure situation, the circuit is broken and a signal sent to indicate that the disk has burst.

Abstract: A variable reluctance transducer system incorporating digital control of parallel resonant circuits including two inductive sensors L1 and L2 on each side of a flat diaphram. The dual variable reluctance elements provide dual frequency signals for digital calculation to obtain a quotient of the frequencies, thereby substantially eliminating the resonant frequencies as a variable in the accuracy of the device. Manipulation of the produced quotient by a micro-controller 10 employing digital calibration tables stored in a programmable read only memory 14 allows calibration reponsive to a temperature sensor 16, thereby substantially eliminating temperature induced errors in the system, further increasing accuracy.

Abstract: A fuel-flow alarm includes a fuel-flow detector for detecting the volume of fuel flowing in a conduit connecting a fuel tank to an engine fuel supply device and provides a warning when the volume of fuel is either above or below predetermined limits. The fuel-flow alarm includes a setting unit used to pre-set fuel-flow limit values for various operational states of the engine, detectors which detect the operational status of the engine, a compensation unit for adjusting the pre-set fuel flow limit values in dependence upon the operational status of the engine and a comparator which compares the limit values outputted from the compensation unit with the actual, detected flow rate. When a determination is made that the fuel flow rate exceeds at least one permissible limit value, the alarm is activated.

Abstract: Methods and apparatus for the inspection of air cargo including passenger luggage for pressure sensitive bombs. In accordance with the method, the air cargo is placed in a pressure vessel, which is then pressure cycled between a super-ambient pressure and a sub-ambient pressure duplicating the pressure at a substantial altitude. Cycling in this manner will trigger pressure sensitive switches set to set off, or initiate a timing device to set off, a terrorist bomb. The apparatus includes a pressure vessel with large blowout ports for venting the same to the atmosphere upon an extraordinary pressure rise indicative of the detonation of an explosive charge within the chamber. Also preferably located within the chamber are sensors, typically electromagnetic noise sensors, for sensing electromagnetic radiation characteristic of a switch closure turning on current to a bomb timing device.

Abstract: A pressure monitoring device for indicating to the administrator of an injection to a patient that an excess of force has been exerted on the plunger and thereby the fluids contained within the syringe.

Abstract: This is a specialized hand-held and battery-powered unit for field testing of backflow valves. It displays and prints a permanent record of simultaneous source- and discharge-port pressure values and their difference. To reduce operator distraction and confusion during backflow tests the source and discharge values are automatically equalized, bringing the difference to zero, whenever the actually sensed pressures are within a threshold differential such as 0.2 pounds per square inch. Preferably two pressure sensors are provided for connection to source and discharge ports respectively, yielding independent analog electrical signals representing the pressures; and two independent analog-to-digital converters respond to the two sensor signals respectively. Digital input signals from the converters pass to a microprocessor--which controls a digital display to show the three values continuously.

Abstract: The invention concerns a simple, inexpensive and small detector, particularly for use in the medical pumps, for detecting over-pressure in a pipe (1) and setting off an alarm when an over-pressure is detected. The detector for detecting over-pressure in the pipe (1) along which a fluid (3) flows may comprise a T junction (5) for deriving a fraction of the flowing fluid (3) from the pipe (1); at least one tube (7) wherein there is fitted at least one obturating member (9); and an assembly for detecting the displacement of the obturating member (9) in the tube (7) and for generating a signal in response to detecting displacement of the obturating member (9).

Abstract: An oil pressure alarm device for a motor vehicle comprises, an oil pressure switch, the oil pressure switch being activated to a conductive state when the circulation oil pressure of engine oil decreases below a predetermined level, alarm device for forming first current path in response to a conductive and non-conductive operation of the oil pressure switch after main power switch is turned on, condition detecting device for producing a detection signal in response to rotation of the engine, delay device for producing an enabling signal after a predetermined time of period has elapsed from when the detection signal is supplied from the condition detecting device, and alarm control device for forming second current path for the alarm device when the oil pressure switch is turned on under the condition that the enabling signal is outputted by the delay device, and for maintaining the second current path while the enabling signal is supplied from the delay device to the warning control circuit.