Abstract: A condensing system has a plurality of heat exchanger elements (2) which are disposed especially in a roof-shaped manner and to which cooling air (K) is fed via fans (3). An aerodynamic wall (7) is formed on a perimeter (5) of the condensation plant (1). Arranged on the perimeter (5) is a wind shielding wall (6) which is composed of plate elements (10). The plate elements (10) have a plurality of hollow chambers (9) which extend in a vertical direction. An air flow (L) can be introduced into at least some areas of the thus-configured wind shielding wall (6) in order to form an aerodynamic wall (7) above the wind shielding wall (6).

Abstract: An air conditioning system for cooling an environment in an over-the-road vehicle is provided. The air conditioning system includes an electrically driven, variable speed compressor, which enables operation of the system when the engine of the over-the-road vehicle is not running. The system is modular and is adapted to be installed in the side luggage compartment of the vehicle to enable existing vehicles to be retrofitted to provide no-idle air conditioning. The housing of the system defines two flow paths therethrough; one cold air path and one hot air path. The hot air path is configured to intersect the condenser at least two times, and draws and expels the air through the same wall of the housing. An air direction device is used to reduce the amount of air recirculation through the hot air path to increase the efficiency of the system.

Abstract: An apparatus for shell freezing a liquid content in a container, comprising an endless loop conveyor having a conveying length adapted to convey plural containers such as pharmaceutical vials, incorporating plural rollers to spin the containers as they are conveyed by the conveyor, and a return length, along at least part of the return length the rollers are immersed in a cooling liquid at a temperature below the freezing point of the liquid content of the containers, and along the conveying length the rollers are entirely above the surface of the cooling liquid. A preferred cooling liquid is liquid nitrogen, the evaporating vapour of which can be used to shield vials on the conveying length.

Abstract: A freezer housing for a freezer for cooling and/or freezing of products lying on a conveyor belt, and which are conveyed through a freezing zone for the freezing, where upper ejector plates are provided above the conveyor belt and lower ejector plates are provided below the conveyor belt for inflow of air into the freezing zone while applying an impingement principle, where the ejector plates are provided with transverse air return ducts.

Abstract: A refrigerator includes a refrigerator main body having a storage space; a door installed at the refrigerator main body to open and close the storage space; and a receiving device including a storage basket which is accommodated in the storage space and has a storage chamber to store a product and an auxiliary basket which is installed to be spaced from a bottom of the storage basket and has an insertion groove to receive a thin product such that the thin product is stored in the storage chamber in a standing state. According to the refrigerator, since a product having a large width and a small thickness can be stored in a standing state, it is possible to conveniently store a product such as a pizza box and efficiently use a storage space.

Abstract: The present invention relates to a cool air supply structure of a storage receptacle for a refrigerator. The present invention comprises one or more box casings detachably installed in a refrigerating chamber, each box casing having a mounting space and a channel through which cool air flows, the cool air being supplied from a cool air supply source through a cool air supply port formed in a side surface of the refrigerating chamber; and one or more storage receptacles, each storage receptacle being withdrawably installed in the mounting space, wherein food accommodated in an accommodation space provided in the storage receptacle is indirectly cooled by the cool air that flows through the channel. According to the present invention, there is an advantageous effect in that the food accommodated in a plurality of storage receptacles can be stored to be fresher by indirectly cooling the food and simultaneously the supply of cool air can be controlled depending on the use or not of the storage receptacles.

Abstract: An air blowing arrangement for a combined refrigerator of the forced ventilation type and that comprises: a cabinet formed by an outer case and by two inner cases spaced from each other by a thermal insulating filler and defining a freezing compartment and a refrigerating compartment; and an air diffusing element defining at least one air distributing duct, having an air inlet in communication with the interior of the inner case of the freezing compartment and a plurality of air outlets opened to the interior of the refrigerating compartment. The air diffusing element is disposed in the interior of the thermal insulating filler and seated against the rear wall of the inner case of the refrigerating compartment, said rear wall being provided with a plurality of windows aligned with respective air inlet openings of the air distributing duct.

Abstract: An aircraft galley refrigeration system is provided which, in one embodiment, includes: first and second galleys; a first chiller for providing a first heat transfer fluid to the first galley; a second chiller for providing a second heat transfer fluid to the second galley; and a heat exchanger including a first circuit and a second circuit, the first circuit connecting the first galley with the first chiller, and the second circuit connecting the second galley with the second chiller. In another embodiment, the system includes a first cooling subsystem with a first heat transfer fluid, a second cooling subsystem with a second heat transfer fluid, and a heat exchanger that thermally couples the first and second cooling subsystems for distributing heat between the first and second heat transfer fluids.

Abstract: The manner in which you use this cooler is you first remove the lid, then remove the inner tray. You then add ice (as much or as little as desired), water (enough to cover ice), a hand full of rock salt and the desired beverage containers. If traveling reinsert inner tray and lid and that's it, But if you are where your going and you want a drink fast just simply mix water with your hand and set timer to Cold, Ice Cold, Arctic Cold, or Liquid Ice and when bell rings your drinks are ready. You can also reverse the lid and put ice and drinks in it as a serving cooler. The inner tray has four equal compartments for storing cold foods or for serving from. The Timer is also a great tool for grilling or as a reminder, when set, to keep an eye on the grill.

Abstract: An absorption refrigeration system using a two or more substance solution to achieve refrigeration that eliminates the need for a pump. The vapor pressure in a generator column is balanced by a pressure head of liquid solvent-solute solution. Re-dissolved solute is returned to the generator by causing some of the vapor to pass through a perforated tube or the like into the solvent where it is absorbed. At least some of the vapor is cooled to liquid solute and then expanded through an expansion valve into an evaporator to create a refrigerator. Hot vapor from the generator column can be passed through a jet to create a low pressure in the evaporator. No pump is necessary since the liquid is returned to the heating area of the generator by gravity. Closed loop control of the heating can optionally be achieved by using a pressure sensor in the rising generator column.

Abstract: A variable speed drive is provided for a compressor in a refrigerant system. When a low load situation has been determined by the refrigerant system controls, the variable speed drive moves the compressor to a lower speed mode of operation. In this case, if a speed is so low that it cannot ensure adequate oil lubrication of the compressor elements, then the motor speed is periodically increased to a level that will ensure proper lubrication. In this manner, a variable speed drive compressor can be operated at an extremely low speed to precisely match load demand on a refrigerant system. The invention can be extended beyond refrigerant system applications and to any oil-lubricated compressors whose lubrication is speed dependant.

Abstract: In an integrated unit for a refrigerant cycle device, at least one evaporator is integrated with an ejector having a nozzle portion for decompressing refrigerant and a refrigerant suction port from which refrigerant is drawn. In the integrated unit, an insertion hole is provided in a longitudinal end surface of a tank of the evaporator such that the ejector is inserted from the insertion hole into the tank, and a plug for sealing the insertion hole is provided. Furthermore, a spacer is configured to have a gap between the plug and the ejector, and a fixing member is disposed between the longitudinal end surface of the tank and an expansion valve, for fixing the expansion valve to the longitudinal end surface of the tank. In the integrated unit, at least one of the fixing member, the plug, and the spacer is made of a resin material.

Abstract: A device filled with ice and water provides for the quick cooling, and cool maintenance at ice temperature, of beer kegs and other beverage containers.

Abstract: For simple and rapid production of a shaped body comprising fused silica and a shaped body which leads to virtually no contamination of a melt in contact with the shaped body even at high temperatures, the invention provides a process comprising the steps: a) provision of fused silica in the form of essentially amorphous SiO2 grains of which not more than 5% have a diameter greater than 15 mm, b) addition of water to the fused silica grains to produce a slip, c) casting of the slip into a mould which comprises a hollow body having the inverse shape of the shaped body to be produced, d) drying of the slip to give an intermediate body, e) sintering of the intermediate body at a sintering temperature at which at least part of the fused silica is transformed from the amorphous modification into a crystalline modification, f) cooling of the sintered shaped body to a temperature below 300° C., so that a microstructure containing crystalline SiO2 is formed, and also a shaped body which comprises at least 99.

Abstract: A zircon composition having a multi-modal particle size distribution is disclosed. The multi-modal zircon composition comprises greater than about 40 parts by weight of a coarse zircon component having a median particle size of from greater than about 3 ?m to about 25 ?m, and less than about 60 parts by weight of a fine zircon component having a median particle size of 3 ?m or less. Methods for manufacturing a green body and a fired refractory ceramic body comprising the multi-modal zircon composition are also disclosed.

Abstract: As the endface preparation of the coated optical fiber, cutting using thermal stress is carried out, and a ceramic heater is used as a heat source, thereby making it possible to provide a coated optical fiber endface preparation method and tool capable of increasing the cutting success rate of the coated optical fiber. The coated optical fiber is removed of its coating to obtain the bare optical fiber. The bare optical fiber is heated by the heat source consisting of the ceramic heater, and is cut by further adding stress to part of the bare optical fiber which has been provided with the thermal stress. When heating the bare optical fiber, the product of a temperature and the heating time of the heat source is made 3000° C. sec or more.

Abstract: A method and apparatus are described, which permit a simple, rapid manufacture of an end of an optical fiber bundle. According to the method a metallic sleeve is placed on an end section of the bundle, the end section with the sleeve on it is positioned in a shaping tool without pressing the sleeve and then pressure is exerted on the sleeve exclusively in a radial direction by press jaws of the shaping tool. In the optical fiber bundle made by the method the outer optical fibers (4?) of the optical fiber bundle (1) are embedded at least partially in the sleeve material. The apparatus for making the end of the bundle (1) with the sleeve (10) has a shaping tool (20) including at least two radially movable press jaws (22a-22f) that substantially surround the sleeve (10).

Abstract: A lint filter of a laundry machine is provided. In the lint filter, a case is provided, a front filter is installed in the case and the front filler includes a hook formed at at least one side, and a rear filter is mounted on a back of the front filter.

Abstract: The present invention relates to a laundry machine, and the laundry machine includes main body forming an external appearance, and a drum which is rotatably installed in the main body to accommodate a laundry, wherein an opening is formed at one side of the main body to selectively connect an inside of the main body to an outside.

Abstract: A universal lock assembly (10) has a linearly-extending member (20) having a first end with a stop member (22). Extending linearly and away from the stop member (22) is a shaft member (24) having a continuous plurality of circumferential ridge (28) and indentations (27) defined within it. The indentations (27) are generally arcuate and the ridges (28) are formed from the peaks that are disposed between adjacent arcuate indentations (27). Given the circumferential nature of the ridge (28) and the indentations (27), the linearly-extending member (20) can be positioned in any position relative to a 360° radial axis. A lock sub-assembly (30) is provided which has an aperture (37) for receiving the shaft (24) of the linearly-extending member (20).

Abstract: A lock to be mounted on a door, including a rotor assembly and a stator assembly, where the rotor assembly is connected to a locking/unlocking actuator to allow locking and unlocking of the lock when an appropriate key is inserted into the lock, wherein the rotor assembly includes a means for retaining the rotor assembly, where the retaining means is fixed by clipping the retaining means onto the stator assembly, where the fixing part(s) of the retaining element are intended to be positioned between the stator and a handle of the door.

Abstract: An anti-theft device includes a first steering column, a second steering column, a clutch and an actuating unit. The first steering column is connected to a steering wheel. The second steering column is connected to a universal joint connected to a steering mechanism. The actuating moves the clutch between a first position for connecting the first steering column to the second steering column and a second position for disconnecting the first steering column from the second steering column.

Abstract: An electromechanical combination lock is provided. It comprises a rotating handle assembly, a locking assembly, an electric actuator and a control mechanism. The locking assembly comprises an actuation device and has an unlocked state thereof in which said handled assembly is rotationally coupled to said actuation device for imparting an opening or closing operation through rotation of the handle and has also a locked state in which said handle assembly is rotationally uncoupled from said actuation device. The electric actuator is operatively associated with the locking assembly for switching the locking assembly between the locked and the unlocked states while in corresponding first and second operational modes of the electric actuator. The control mechanism serves for causing the electric actuator to switch between the two operational modes, and is associated with the rotating handle assembly.

Abstract: The present invention discloses a keyholeless lock device, which comprises a lock casing, a motor, an induction antenna, a circuit board, a control chip, a lock handle and a latch bolt. When the user is inside door, he may rotate the lock handle to open the door. When the user is outside the door, he has to use an induction key to open the door. The induction key can send out encryption information to the induction antenna, and the control chip uses a decryption procedure to judge whether the induction key is authentic. If the induction key is authentic, the motor will retract the latch bolt into the lock casing. When there is a power failure, the induction key will be inserted into the lock casing and function as the power source of the induction antenna, the circuit board and the control chip. As the keyholeless lock device of the present invention abolishes the traditional keyhole and lock cylinder, thieves are unlikely to burglar with their lock-picking skill.

Abstract: A dual-locking device includes a housing, a shackle and a combination locking mechanism and a key-operated locking mechanism. The shackle is movably mounted on the housing. The shackle comprises a controlling portion, a hook portion, and a root portion. The controlling portion is located inside the housing. The hook portion extends outside the housing from one end of the controlling portion. The root portion extends inside the housing from the other end of the controlling portion. The combination locking mechanism is disposed in the housing and capable of controlling movement of the controlling portion by entering a code. The key-operated locking mechanism is disposed in the housing and capable of controlling movement of the root portion by a key.

Abstract: A dial assembly for a master key controlled combination lock is disclosed herein, the dial assembly having: a dial having a front side, a back side and a gripping surface disposed therebetween, the front side having an opening therein; a key plug having a lock cylinder rotatably disposed therein, the lock cylinder having a key hole end and a lever end, the lock cylinder being configured to receive a master key having a particular key code sequence in the key hole end, the key plug being configured to be installed within the dial through the opening of the dial and the lever end is configured to actuate a combination lock; and a cover plate for securing the key plug in the dial, the cover plate having a face portion and an engagement portion, the face portion having an aperture extending therethrough, the aperture being configured to rotatably receive the keyhole end of the lock cylinder therein and the engagement portion is configured to secure the face portion in the opening of the dial when the cover plate

Abstract: A high security key blade and key for use with a lock having a cylindrical shell, a key plug which is rotatably mounted in the shell, a longitudinal key slop in the key plug, and at least one locking tumbler assembly cooperating with the key being inserted into the lock. The locking tumbler assembly includes a pair of independently movable tumbler segments which are positionable in different elevational positions in a common cavity.

Abstract: A key case includes a housing within which there is a plurality of rotationally mounted key holders. Each key holder is connected to an individual key. A plurality of buttons is mounted on the housing. Pressing on a selected button enables a desired key to swing out of the housing and move into an outwardly projecting position wherein it can be used to unlock a lock. In an alternative embodiment of the invention a selector assembly which is slideably mounted on the housing supports an operating button which facilitates pressing the desired button to select a key.

Abstract: A controlled release sulfur coated fertilizer with improved abrasion resistance is produced by applying a precursor coating that forms a cohesive film which adheres to the fertilizer substrate particles and to the sulfur that is subsequently applied in molten form. The improved fertilizer also optionally comprises a sealant coating applied after the molten sulfur. This invention is to the composition of the fertilizer and the method of production.

Abstract: This invention relates to the use of nitrogen- or calcium-containing fertilizers to improve the performance of S-(+)-abscisic acid (S-ABA, ABA) or ABA salts on plants. This invention also relates to the use of ABA to reduce the phytotoxicity of foliar applied fertilizers.

Abstract: The invention relates to a method for deep rolling the passes or radii on the transitions between journal and cheeks or flanges of crankshafts by means of a deep rolling device (1) of a deep rolling machine, said deep rolling device having a lazy tongs-type design. The deep rolling device (1) has two tongs arms (2, 3) that are articulated to each other via a pivot joint (24). The corresponding outer ends (4, 5, 9, 10) of the tongs arms (2, 3) are provided with a deep rolling tool (6) or a force generator (11) for generating the deep rolling force. A measuring tape (18) and a sensor (19) which are provided on the pivot joint (24) are used to measure the impression depth of the deep rolling rollers (12) under the effect of the deep rolling force. A measuring device (22) mounted on the exterior (21) of a tongs arm (2) is used to measure the degree by which the tongs arm (2) bends under the effect of the deep rolling force.

Abstract: An apparatus for leveling thin metal strip moving longitudinally generally in a plane in a travel direction has at least one upstream roll rotatable about an axis and engaging the strip, at least one downstream roll rotatable about an axis and engaging the strip downstream of the upstream roll, and a drive connected to at least one of the rolls for exerting tension on the strip between the rolls. In accordance with the invention pivoting one of the rolls is pivoted about an axis substantially perpendicular to the plane or parallel to the direction so as to vary the tension in the strip across a width of the strip and thereby locally plastically deform the strip to level it.

Abstract: A metal strip is stretched as it is moved longitudinally generally continuously between an upstream traction-roll set and a downstream traction-roll set. The roll sets are differentially driven—with the downstream set moving at a slightly higher peripheral speed than the upstream set—so as to apply to the strip in a region between the sets a tension generally equal to a stretch limit of the strip. The strip is locally heated or cooled at an upstream location in the region between the roll sets so as to set in the strip in the region a temperature distribution that is nonhomogeneous transversely across the strip at least immediately downstream of the upstream location.

Abstract: An I/O endforming tool for forming an end of a tube, the tool having a cone ring expandable and contractable conical I/O jaw assembly, a barrel assembly, a plurality of I/O fingers and mandrel assembly, wherein the I/O jaw assembly has a plurality of conical jaw segments, one segment adjacent two neighbouring segments, each segment having a recess within each of its sides adjacent each neighbouring segment and biasing member retained within each recess to effect a biasing effect between adjacent jaw segments the improvement wherein each recess formed at a portion of the outer circumference of each segment as to define a radial trough when the jaw assembly is in its expanded position; and the biasing member is a solid, non-metallic deformable member retained within a circumferential recess defined by a pair of adjacent the troughs when the jaw assembly is in its contracted position. The process of manufacture provides improved saving in time, handling, efficiency, consistency and quality.

Abstract: A modular rolling mill comprises a plurality of rolling units having work rolls configured and arranged to progressively reduce the cross sectional area of a product received along a mill pass line. Gear units are mechanically coupled to each rolling unit, with each gear unit in turn being mechanically coupled to a driven line shaft by first bevel gear sets. The ratios of the first bevel gear sets progressively increase from the first to the last of the gear units to thereby accommodate a progressively increasing speed of the product being rolled. A second bevel gear set is associated with the last gear unit. The ratio of the second bevel gear set is the same as the ratio of the first level gear set of the penultimate gear unit. The line shaft is selectively coupled to the last gear unit via one or the other of its first and second bevel gear sets.

Abstract: A method for producing a formed body including the steps of introducing a fluid material supplied from two or more material supply holes of a rectification plate into a drawing die, homogenizing the flow rate distribution of the fluid material in the drawing die using one or more wires stretched from the material supply holes to near the exit section of the drawing die, and extruding the fluid material from the exit section of the drawing die in which a prescribed forming pattern is formed by two or more wires. The wires form hollow holes through the formed body.

Abstract: In a method of cutting high-tensile workpieces, in particular sheet metals of martensite steel, the workpiece is subjected to a bending stress prior and during a shearing process. The bending stress causes a substantial component of a tensile force transverse to a desired cutting contour. Tensile stresses are superimposed to the shearing stresses, which favor the beginning of the workpiece separation. The bending stress is preferably selected so that the resulting tensile stress exists at a side facing the cutting tool.

Abstract: A method for forming a smooth cylindrical inside wall of a tube is described. The tube is heated and a shaped arbor is inserted into the tube. The tube is forced against the arbor to shape the interior of the tube in general conformity to the arbor and the arbor is removed. The tube may be cut into several sections shaped to be useful as tapered roller bearing cups.

Abstract: Disclosed herein is an electrical connector tool spanner plate. The electrical connector tool spanner plate includes a first section and a second section. The first section includes an aperture and a first opening. The aperture extends along a majority of a length of the first section. The spanner plate is configured to surround an electrical connector tool cam mechanism at the aperture. The second section includes a second opening. The second section extends from the first section in a general cantilevered fashion. The second opening is proximate a free end of the second section. The aperture is between the first opening and the second opening.

Abstract: One embodiment of the present invention is an alignment apparatus useful to align a test head that includes: (a) two or more fluid chambers disposed in fixed relation to each other, the chambers having a movable wall and one or more apertures for admitting or releasing fluid; (b) fluid channels coupled to the one or more apertures that enable fluid to flow between at least two of the fluid chambers; and (c) one or more valves disposed to enable or to stop the flow of fluid through one or more of the one or more fluid channels.

Abstract: The invention relates to pseudo porosity standards, and methods for their manufacture and use, which may substantially mimic the effect porosity has on ultrasonic sound as it passes through a composite laminate. An ultrasonic inspection reference standard for composite materials having porosity may include a member having at least one thickness. The member may be defined by at least one hollow, non-spherical shaft. The member may be manufactured from a fiber-free polymer resin using a stereo lithography process. The non-spherical shaft may scatter and attenuate ultrasonic energy. The reference standard may replace more costly, porous, fiber-reinforced, composite reference standards in the aircraft industry and in other non-aircraft applications.

Abstract: A device is provided for measuring the gas content in a molten metal, the device including an immersion end having a gas-collecting body, a gas supply line opening on the immersion end, and a gas discharge line for the gases passing through the gas-collecting body. The gas-collecting body contains materials, which in contact with the molten metal do not form liquid reaction products.

Abstract: A photo acoustic detection cell (6) is located within the optical cavity (3) of a cavity enhanced absorption spectroscopy apparatus (3,4,5). When a sample in the cell (6) absorbs radiation from a pulsed radiation beam coupled into the cavity (3) pressure waves are generated that are detected by a microphone (9). A detected signal (10) output by the microphone (9) may be processed to determine a value for the concentration of an absorber in the sample.

Abstract: A surface acoustic wave based CO2 gas sensor that utilizes zeolites or transition metals doped zeolites as a sensing layer. Such zeolites can be used “as is” or doped with metal oxide semiconductor materials such as, for example, TiO2, ZnO, SnO2, electrolytes etc. to vary the sensor sensitivity for various gases. Zeolites can be configured as thin or thick films by employing nanopowders in suitable dispersants. The addition of zeolites, catalytically modified with chromium, results in a controlled selectivity to various gases based on shape and size effects.

Abstract: A device is disclosed for sensing a fluid, such as in a ventilation duct. In at least one embodiment, the device includes a sensing element, a housing accomodating the sensing element, and a supply duct and a discharge duct, which ducts at one end commucicate with the housing and which ducts at the other end communicate with an object that is to be sensed. In at least one embodiment, the housing is formed with a first passage portion for the fluid that is to be sensed; that the sensing element is positioned in the first passage portion; and that the supply duct opens into said first passage portion and that the discharge duct is connected to a discharge opening formed in the first passage portion and positioned at a considerable peripheral distance from the mouth of said supply duct in the first passage portion, so that the fluid that is to be sensed is actively made to pass the sensing element.

Abstract: A sensor control apparatus includes an applied voltage control circuit connected to the positive terminal of a sensor element. The applied voltage control circuit includes a reference power supply and a noninverting amplifier circuit connected to the reference power supply. An AC power supply circuit, a buffer and a current measurement resistance are connected in series to the negative terminal of the sensor element with the current measurement resistance disposed between the AC power supply circuit and the sensor element. One terminal of the current measurement resistance, which is on the side opposite to the sensor element, is held at a reference voltage (center voltage of an AC voltage generated from the AC power supply circuit). Voltage at an intermediate point between the current measurement resistance and the sensor element is inputted via a low-pass filter to the noninverting amplifier circuit of the applied voltage control circuit.

Abstract: A method and system for deriving fluid leak information are described. A plurality of sealing elements are introduced into the pipeline at a location upstream of the leak, and at least some of the sealing elements are drawn towards the leak to cause a sealing event which reduces fluid seepage. A pressure change caused by the sealing event is detected, and associated time data is used to derive information about the leak. In one embodiment, leak location information is derived. In an alternative embodiment, pressure transient information is used to derive leak size information.

Abstract: Method and apparatus for detecting tank leaks, in which a gas pressure acts on a fluid which is situated in a tank, and in which the gas pressure in the tank or tank system is changed, wherein a tank leak is detected by evaluation of a temporal profile of a sum pressure of the fluid which is situated in the tank.

Abstract: The invention relates to a substrate material for analyzing fluids which is elastic and allows radial lateral movement of sample within the substrate material upon application of pressure.

Abstract: A nanoparticle size classifier comprising a variable flow rate system with a single diffusion element 3 placed inside a cell 2 containing inlet 1 and outlets 6 and 7, an aerosol filter 8, flow meter 9, pump 10 and pump controller 11, which enables a plurality of measurements to be obtained by means of passing an aerosol through the diffusion element 3 at various flow rates. Preferably, outlet of the diffusion cell is connected to a particle counter 5 via a three-way valve 6. The diffusion element has a net or screen that permit air through but capture some particles.