Abstract: A fluid flow arrangement includes a manifold defining a fluid passage. A pressure sensor system is in fluid communication with the fluid passage. The pressure sensor system has a first sensor arranged along a first sense line and a second sensor arranged along a second sense line. The first and second sense lines are in fluid communication with the fluid passage. The first sense line has a first resonant frequency and the second sense line has a second resonant frequency. The second resonant frequency is different than the first resonant frequency.

Abstract: A pressure indicator includes a body, a piston, first and second biasing elements, and a rotatable disc. The piston is disposed at least partially in a bore of the body at a first longitudinal axial position relative to the body when pressure of fluid acting on the base is below a threshold pressure. The first biasing element is disposed between a base of the piston and a shoulder of the body, wherein a force of the first biasing element is overcome by pressure of fluid acting on the base at or above the threshold pressure, thereby allowing the piston to move to a second longitudinal axial position. The rotatable disc has a first rotational position when the piston is in the first axial position. The second biasing element is configured to urge the disc to a second rotational position when the piston is in the second axial position.

Abstract: The present application discloses a vacuum sealed container, including a container body, a container lid, a vacuum generator, at least one magnifier and an indicator. The container body includes a first wall and a bottom surface, wherein the first wall and the bottom surface define an accommodation space. The container lid is coupleable to the container body. The vacuum generator is coupled to the container lid to evacuate fluid from the accommodation space. The at least one magnifier is coupled to the container body. The indicator is coupled to the container. A method for using the aforementioned vacuum sealed container is also disclosed.

Abstract: A strap watch with a first hand normally indicating the hours, a second hand normally indicating the minutes, where appropriate an additional hand, at least one accelerometer, and an electronic control unit which is configured so that it normally causes the time to be indicated by the hands, calculates at least one individual activity amount representative of a physical activity of the user based on information collected by the accelerometer, and displays the activity amount by means of at least one of the hands, whereby the user can very simply view one or more amount(s) relating to his or her physical activity on a compact and conventional analog watch interface.

Abstract: It is challenging to detect end of stroke for hydraulically actuated, reciprocating piston pumps for a variety of reasons. When the pump pressurizes a process fluid to a 10 relatively low pressure the magnitude of hydraulic fluid pressure is not as distinct compared to the magnitude of a pressure drop across a shuttle valve employed to detect end of stroke, which makes detecting the end of stroke event difficult. A method is disclosed for detecting end of a piston stroke in a hydraulic motor comprising a reciprocating piston with a shuttle valve. The method comprises 1 detecting end of piston stroke when a magnitude of a rate of change of hydraulic fluid pressure is substantially greater than a magnitude of a mean rate of change of hydraulic fluid pressure over said piston stroke; and noise in a hydraulic fluid pressure signal is substantially negligible.

Abstract: A rotor blade spar for use in a rotor blade is provided comprising a housing defining an interior and having an open end. An end cap is affixed to and sealed on the open end to seal the interior from an exterior outside of the housing. The end cap includes a first port and a second port fluidly coupling the interior to the exterior. A port sealing system closes the first and second ports. The first port is connectable to an external device configured to generate a pressure differential between the interior and the exterior sufficient to create an airflow through the first and second ports which removes a liquid disposed in the housing through one of the first and second ports.

Abstract: An endoscopic vacuum controller may include a housing having a vacuum inlet, a vacuum outlet configured to be coupled to a vacuum source, and a vacuum passage fluidly coupling the vacuum inlet to the vacuum outlet. The vacuum controller may also include an actuator supported by the housing and configured to control the flow of fluid through the vacuum passage. An indicator may be supported by the housing to provide an indication that a predetermined vacuum level is being drawn at the vacuum inlet. The vacuum controller may include a connector to detachably couple the housing to an endoscope shaft. The connector may be configured to slidably couple the housing to the endoscope shaft to allow adjustment of the controller along the length of the shaft while the housing remains coupled to the shaft.

Abstract: A wear-indicating bearing and method of detecting wear in a bearing are disclosed. The bearing includes a bearing stack having a first end and a second end with a longitudinal axis defined between the first and second ends. The bearing stack includes a plurality of elastomeric layers sandwiched between non-elastomeric shim layers, where each layer is concentric about the longitudinal axis. At least one elastomeric layer is a marker layer configured to indicate wear of the bearing. The marker layer is made up of a first elastomeric composition and a second elastomeric composition, wherein the first and second elastomeric compositions have optically different characteristics. Upon fatigue of the bearing, the first elastomeric composition is detectable through a fracture extending from an exterior surface of the bearing stack.

Abstract: The present invention relates to a hydraulic attachment comprising a hydraulic circuit, the attachment being a construction or demolition tool, in particular a hydraulic breaker, demolition shears, scrap shears, a pulveriser, a gripper, a crusher bucket or a compactor, which can be mechanically connected to a support device and hydraulically connected to the hydraulic system of the support device. In order to enable the hydraulic circuit to be opened quickly and safely within an attachment and, in particular, to make it possible to display the presence of a particular pressure level within a hydraulic attachment and to determine whether a dangerous residual pressure is present in the system, a hydraulic attachment is proposed that has a residual pressure display (40) which is connected to the hydraulic circuit of the attachment in a detachable or non-detachable manner.

Abstract: An indicating assembly for a container in which pressurized fluid is stored comprises a valve assembly connected to the pressurized container and having a fluid passage for receiving the pressurized fluid and a piston movable within the valve assembly along a longitudinal axis in response to fluid pressure within the fluid passage. The assembly further comprises an indicating member movable in response to longitudinal movement of the piston between a first condition providing a first indicator portion representing fluid pressure below a threshold pressure and a second condition providing a second indicator portion representing fluid pressure above the threshold pressure.

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: The invention relates to a spray gun comprising a gun body (1), a nozzle arrangement (9) arranged on said gun body (1), a compressed air supply channel (22, 23) which is arranged in the gun body (1) and which comprises a valve arrangement (17) for controlling the compressed air supply to the nozzle arrangement (9), a device (31, 33, 37, 42, 40) for controlling the compressed air supply, and a pressure measuring device (35) for recording and displaying the pressure in the compressed air channel (22). Said invention is characterized in that said pressure measuring device (35) is secured in a removable manner to the device (31, 33, 37, 42, 40) for controlling the compressed air supply.

Abstract: A pressure indicator for indicating pressure of a pressure source. The indicator comprises a first reservoir which defines a first enclosed volume having a first inlet pipe for communication between the first enclosed volume and a first source of pressurized fluid. A passage which provides a flow path for the pressurized fluid.

Abstract: A simple and reliable anticipatory failure indicator is provided for fluid circulation piping, and a fluid cooling arrangement including such an indicator is provided. The indicator includes a first sacrificial member, which is designed to be in direct contact with the fluid within the piping and designed to be weaker than the piping. The indicator includes a chamber, which is isolated from the fluid circulation at least partly by means of the first sacrificial member. The indicator includes an electrical response member, which is arranged into the chamber and which is configured to produce an electrical response upon exposure to the fluid, which has entered to the chamber via a failed sacrificial member. Accordingly, the indicator is configured to provide an electrical response as a direct indication of a failed sacrificial member and as an anticipatory indication of failed piping.

Abstract: A pressure indication device is provided to connect to an inflation mechanism of an inflation machine. The pressure indication device includes a linearly movable plate and an elastic element. A scale bar having graduations is provided along a moving path of the plate. The elastic force of compression of the elastic element serves as a reaction force (restoration and returning force) for the linear movement of the plate. Correspondingly, a pressure is induced in an air compartment of the inflation mechanism the so that the moving distance of the plate is indicative of the pressure level and thus precise measurement of pressure can be realized.

Abstract: A pressure indicator: a body having a pressure chamber which has an inlet for communication with a fluid; a resilient diaphragm having a periphery sealed against the body and having one side thereof exposed to the fluid within the chamber; an indicating arm having an inner end which is integrally formed with the other side of the diaphragm and an outer end arm which is adjacent to a scale, the arrangement being such that pressure of the fluid within the chamber causes resilient deformation of the diaphragm which in turn causes the outer end of the arm to move relative to the scale thereby indicating the pressure of the fluid in the chamber.

Abstract: An administration set flow condition monitor (30) includes a body member (32) configured to communicate with a fluid conduit (12) of the administration set (10). A flow monitoring mechanism (40) is carried by the body member (32) for indicating flow in the fluid conduit (12) of the administration set (10). An enunciator (56, 58) is associated with the flow monitoring mechanism (40) to indicate flow condition in the fluid conduit (12) of the administration set (10).

Abstract: A pressure indicator for indicating pressure of a pressure source. The indicator comprises a first reservoir which defines a first enclosed volume having a first inlet pipe for communication between the first enclosed volume and a first source of pressurised fluid. A damping passage is provided in fluid communication with the first enclosed volume. A pressure oscillation damping means is provided in the damping passage. The damping means comprises a moveable body constrained within a limited range of motion along the damping passage.

Abstract: A pressure indicator for indicating pressure of a pressure source. The indicator comprises a first reservoir which defines a first enclosed volume having a first inlet pipe for communication between the first enclosed volume and a first source of pressurised fluid. The first inlet pipe defines a nominal communication path length between the first enclosed volume and a first source of pressurised fluid. A member is provided in the first inlet pipe which defines one or more communication paths of greater length to that of the nominal communication path length.

Abstract: Embodiments of the present invention relate to medical devices that provide signals to diagnostic equipment such that functionality of an implantable member can be determined. In particular, various designs and structures are utilized to signal tissue growth on an implantable member such as a stent. The tissue growth can limit flow through the stented lumen. If the growth has a thickness above a certain limit, a signal can be detected by diagnostic equipment such that a proper diagnosis can be made.

Abstract: A pressure indicating device includes a case including a gas passage, and a movable indicator carried by the case. The indicator has an end in fluid communication with the gas passage and an indicator end projectable out of a portion of the case when pressure in the gas passage is at least a predetermined minimum pressure. A spring may retract the indicator when pressure in the gas passage is below the predetermined minimum pressure.

Abstract: An indicator includes a case mountable in a gas filling passage of a pressure container; a valve element which is urged toward one side of the case connectable to the pressure container, the valve element being movable in the case to a position balanced with gas pressure in the pressure container; a seal member for ensuring gas tightness between the valve element and the case; and an indicating member slidable relative to the case between a position protruding outside the case and a position not protruding. The spring force and a gas pressure force may be equally balanced at first and second balanced positions of the valve element.

Abstract: The invention relates to a method and apparatus for a gauge for indicating a pressure of a fluid, including a gauge having a face where the face has a first plurality of graduation marks, each for indicating a pressure in an ascending direction. The face also has a second plurality of graduation marks, each for indicating a pressure in a descending direction. In addition, the gauge includes a sensor magnet for detecting the pressure of the fluid, a pointer magnet coupled to a pointer and in communication with the sensor magnet for moving the pointer in correspondence with a movement of the sensor magnet, and wherein the pointer traverses across both the first and second pluralities of graduation marks for indicating the pressure of the fluid in either an ascending direction or descending direction.

Abstract: An air filter monitoring system for indicating when to clean or replace a flexible air filter includes an air filter having a peripheral frame and an interior filtering region, a fixed support structure for receiving the air filter and maintaining the perimeter of the filter frame in a generally fixed position while allowing the interior filtering region to flex in response to air flow through the filter, and a filter change indicator having a predetermined bias force. The filter change indicator is arranged to contact the interior filtering region of the filter, wherein when the predetermined bias force is reached, the filter change indicator is activated to notify a user to clean or replace the filter.

Abstract: Singular sealed apparatus and method suitable for confirming pressure measurements in a rebreather prior to use of the rebreather. The singular sealed apparatus may have a canister lid, gas sensors and a processor, all from a rebreather, as well as a pressure sensor, an input device, a processor, an indicator and a pod with a pressure measurement outlet, a gas supply inlet, a relief valve and a gas exit valve. Alternatively, the singular sealed apparatus may have a gas sensor from a rebreather and an analyzer, a pressure sensor, an input device, a processor, an indicator, a lid and a pod with a pressure measurement outlet, a gas supply inlet, a relief valve and a gas exit valve.

Abstract: A pressure display device includes a body having an adjustment valve and a display unit connected thereto. The pressurized air enters into the body via paths and the display unit. The pressure detection member detects the pressure and displays the value of the pressure in the display screen. The display screen can be adjusted its position relative to the body by rotating the rotary part such that the user can check value easily.

Abstract: An air filter system for an internal combustion engine of a vehicle can have an indicator for signaling restricted flow of air through a replaceable air filter member mounted to a filter assembly. At least one sidewall can be associated with the replaceable air filter member to be positioned with an air stream passing through the air filter member. A resettable air filter status indicator can provide a visually perceivable signal external of the filter assembly. The resettable air filter status indicator can be integrally formed in the sidewall for indicating if a mounted air filter member requires replacement in response to air intake differential pressure with respect to atmospheric pressure on a downstream side of air flow through the replaceable filter member being above a predetermined threshold value.

Abstract: An indicator includes a case mountable in a gas filling passage of a pressure container; a valve element which is urged toward one side of the case connectable to the pressure container, the valve element being movable in the case to a position balanced with gas pressure in the pressure container; an O-ring serving as a seal member for ensuring gas tightness between the valve element and the case; and an indicating member slidable relative to the case between a position protruding outside the case and a position not protruding. The O-ring is arranged on the valve element so that the O-ring is in contact with the case to ensure gas tightness when the valve element is in a first balanced position while a gas pressure in the pressure container is e.g. 7 MPa or higher and the O-ring is out of contact with the case not to ensure gas tightness when the valve element is in a second balanced position while the gas pressure is less than e.g. 7 MPa.

Abstract: A pressure indicating device includes a case including a gas passage, and a movable indicator carried by the case. The indicator has an end in fluid communication with the gas passage and an indicator end projectable out of a portion of the case when pressure in the gas passage is at least a predetermined minimum pressure. A spring may retract the indicator when pressure in the gas passage is below the predetermined minimum pressure.

Abstract: An apparatus for surveying the pressure of fluids housed in tanks or flowing through ducts comprises a device (100), an envelope (1) with axial symmetry which forms the external covering of the device (100), said envelope (1) being kept in distal position with respect to a connecting body (2) by a counter spring (3); the envelope (1) axially slides with respect to the body (2) to allow the commutation of the apparatus (100) from a non-active to an active condition; the commutation of the device (100) is due to an external force (F).

Abstract: A valve stem pressure poppet incorporated into a tire valve cap for monitoring tire air pressure. The indicator assembly is screw attached by a connector onto an existing valve stem. The assembly includes a hollow outer tube for housing a slideably disposed indicator, a sealed space above the indicator, a compression spring and a connector end fitting. An air passage runs throughout the length the indicator. Once the assembly is engaged, pressurized air feeds directly through the indicator into the sealed space, forcing the indicator down against the force of the compression spring. If the tire remains above a predetermined critical low pressure point, the indicator will remain in the down “equilibrium” position. However, if the air pressure in the tire drops below the critical pressure point the compression force of the spring will overcome the downward pressure on the indicator, and the indicator disengages or “pops” up.

Abstract: A dust collection apparatus includes a container and a suction pump that sucks dust and transports it into the container. A filter is provided on a side surface of the container. This filter passes air but prevents passage of the dust in the container. A pressure detector detects an internal pressure of the container. The internal pressure of the container fluctuates due to a variation in an effective area of the filter for allowing the air to pass according to the dust collected and accumulated in the container. A dust accumulating quantity calculator which determines a quantity of the dust in the container based on the pressure detected.

Abstract: A vacuum insulation panel comprises a barrier film and a core material and a vacuum detection indicator. The vacuum detection indicator is configured to facilitate the evaluation of the integrity of the vacuum within the vacuum insulation panel. The vacuum detection indicator may comprise a cavity in the core material which allows the barrier material to form a depression when a vacuum is drawn within the panel. Accordingly, as the vacuum is reduced or lost, the depression formed in the barrier material will be similarly reduced or lost. In addition, the vacuum detection indicator may comprise a viewing window configured with electrical contacts above the barrier material to permit the evaluator to readily determine whether the vacuum has been reduced or lost. Further, the vacuum detection indicator may comprise a spring-like device configured within the cavity to urge the barrier film against the electrical contacts.

Abstract: A stopper for a bottle includes a resilient outer body having an axial bore, a rigid inner body disposed within the bore, and a valve actuator moveably disposed within an axial opening of the inner body. A lower flange portion of the outer body extends radially across the bore to an axial aperture having a sealing surface. The valve actuator has an upper operator portion connected to a lower valve body portion by a longitudinally extending shaft portion. The valve body portion is sealingly engageable with the sealing surface of the orifice to close the orifice.

Abstract: A pressure indicator of an underwater camera housing has an indicator support surrounding an opening. An elastomer facing is united with the indicator support. The facing has a free region overlaying the opening. The free region has an inner surface and an outer surface. The free region is deflectable by a relative pressure differential between the inner and outer surfaces. Excessive inward excursion of the free region can be prevented by a backup.

Abstract: A vacuum insulation panel comprises a barrier film and a core material and a vacuum detection indicator. The vacuum detection indicator is configured to facilitate the evaluation of the integrity of the vacuum within the vacuum insulation panel. The vacuum detection indicator may comprise a cavity in the core material which allows the barrier material to form a depression when a vacuum is drawn within the panel. Accordingly, as the vacuum is reduced or lost, the depression formed in the barrier material will be similarly reduced or lost. In addition, the vacuum detection indicator may comprise a viewing window configured above the barrier material to permit the evaluator to readily determine whether the vacuum has been reduced or lost. Further, the vacuum detection indicator may comprise a spring-like device configured within the cavity.

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

Abstract: A valve assembly for an apparatus under pressure, includes a valve casing with a connecting pipe having formed therein a fluid passageway. A valve body is received in the valve casing and movable against a valve seat for sealing the fluid passageway and thereby separate a high-pressure zone from a low-pressure zone. Integrated in a handwheel of the valve body is a manometer which is constraint against rotation, when the handwheel is turned with respect to the manometer. The manometer is in communication with the high-pressure zone regardless whether the valve seat is closed or open.

Abstract: A fan drive checking system, for an air conditioning system in a clean room having a fan filter unit (FFU), includes a flow sensor for sensing air flow inside a housing of a FFU. The sensor provides a sensor signal indicative of normal and adverse flow conditions in the housing. A control portion in data communication with the sensor outputs a control signal responsive to the sensing signal. An alarm in data communication with the control portion provides a warning when the control signal indicates the adverse flow condition.

Abstract: A CO.sub.2 cartridge is permanently attached to a cartridge status indicator so that a user need not perform a detailed inspection to determine if the cartridge has been used or not. If the cartridge has been used, the status indicator will so indicate upon casual visual inspection, and if the cartridge has not been used, the causal inspection will also reveal that fact. The gas is released by two different methods. The first requires only that the user pull a cord. Pulling the cord shifts a support member laterally within the inflator, and previously misaligned legs and bores enter into alignment with one another. When aligned, the legs enter into the bores under the influence of a spring positioned in the inflator and the support member is driven into puncturing relation to a membrane. If moisture is encountered, the cord need not be pulled because the moisture collapses a dissolvable element, and the pierce pin is driven into puncturing relation with the membrane under the force of the spring.

Abstract: An audible waveform system is provided that senses a parameter relating to the ventilation of a patient. The system produces short bursts of sound of a predetermined frequency as the changes occur in that parameter based on certain increments of change. The bursts themselves are preferable at a frequency that is the same for equal pressures but increases and decreases in frequency as the parameter increases or decreases, respectively. In the preferred embodiment, the system provides an audible waveform based on the pressure in the patient airway so that the clinician can receive information relating to that waveform conveniently and without taking attention away from other monitors and/or alarms.

Abstract: A temperature-time-pressure detecting device for a closed heat treatment zone consists of a sealed discoidal-shaped capsule of substantially transparent material adapted for placement within the zone in a generally vertical position. The capsule is formed of two opposed preferably symmetrical circular shell walls sealed around their common rim and defining therebetween a central core region containing a shaped mass of a fusible indicating material having a defined melting point at least as high as the temperature to be detected. The central core region is surrounded by an inner and an outer annular chamber which are concentric with the core region and with one another.

Abstract: A device for detecting soil compaction density comprising at least one shell material forming an enclosure, a failure plane disposed within the shell material which causes the shell material to fail at a preset static or dynamic pressure, and a detector, such as an odoriferous chemical enclosed within the enclosure which is released upon failure of the shell material, thereby indicating that the preset static or dynamic pressure has been achieved.

Abstract: The invention provides a vent cap for automatically discharging a gas container such as a propane cylinder. The vent cap includes threads for securing the vent cap to the neck of the gas container. The vent cap further includes an indicator which has a pin and a button. When the button is manually depressed, the pin engages the valve stem of the check valve which seals the gas container, discharging gas from the container. The button includes a flexible, radially curved central portion which provides oil can action when the indicator is moved between the up position and the down position. A geometrical configuration of the central portion may be adjusted to vary the gas pressure threshold at which the indicator will remain in the down position to automatically discharge a nearly empty gas container.

Abstract: A post depressurization 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, having a housing (102) and a piston (130) for temporality sealing an open end of the housing and outwardly movable in response to a pressure differential not less then a predetermined level generated subsequent to the depressurization of the pressure vessel. The piston and the housing cooperating to define a pressure storage cavity (156). The housing including a valve (122) for permitting the fluid within the pressure vessel to enter the pressure cavity and stabilize at a level substantially equal to the pressure level within the pressure vessel and for inhibiting a rapid decrease in the pressure within the pressure cavity immediately subsequent to depressurization of the pressure vessel.

Abstract: A device for optically displaying the pressure of a medium comprises a housing, a piston within the housing which is movable along a longitudinal axis against a restoring force, and an optically transparent element within the housing having a display surface which is visible from outside the housing. An inner wall of the optically transparent element delimits a cavity which is open towards the piston. A surface of a first color, e.g., green, is mounted on the piston and is movable therewith, the colored surface being received within the cavity of the optically transparent element. The optically transparent element includes a circumferential zone of a second color, e.g., red, which colored zone is not directly visible from outside the housing through the display surface.

Abstract: A filter gauge comprising a piston operable in a pressurized cylinder, the piston having a rod which projects from the cylinder, and grippers mounted within the cylinder and accommodating movement of the piston and rod having indicia indicating the lowest pressure reached in the cylinder as a water conduit to which the cylinder is connected is being drained. The grippers prevent the rod from moving in the opposite or extending direction as the cylinder is being pressured gradually by the water seeping through the filter and equalizing the pressure at both sides thereof.

Abstract: A champagne pressure gauge provides a small tube attached to the inside surface of a bidule inserted into a champagne bottle, such that as the pressure from fermentation increases, liquid is forced up the tube. The liquid level in the tube can be observed through the neck of the bottle, giving a non-intrusive, non-destructive measurement of pressure in the bottle.

Abstract: A gas testing apparatus of the type that directs a stream of gas to be tested through a tube containing reagent chemicals. The apparatus has a connector fitting to enable it to be connected to a closed system containing the gas to be tested, a base member having an orifice that reduces the pressure of the gas delivered to the testing tube to near atmospheric, a sliding cover that encloses the testing tube when it is positioned in the holder, and a rising stem indicator that indicates that gas flow has commenced through the tube. The apparatus also has tube seat seals for insuring that all gas entering the apparatus must flow through and not bypass the testing tube.

Abstract: An ultra low pressure flow sensor consisting of a support gasket defining a flow way and having a thin, pliable membrane extending thereacross with right angle slits formed totally across the flow way portion. An electrical conductor strip is then bonded across each pair of opposing quadrants of the membrane in continuous connection to an electrical indicator circuit. The conductor strip across each pair of membranes is centrally notched to a preselected depth of cut thereby to adjust the flow pressure break strength.