56results about How to "Guaranteed ventilation effect" patented technology

The utility model discloses a digital temperature control type electric blanket controller, which relates to the technical field of electric blanket controllers and comprises a controller body, a protective net cover is arranged on the lower surface of the controller body, a group of heat dissipation grooves are formed in the lower surface of the controller body, and a fixing seat is fixedly connected to the lower surface of the controller body. A protective net cover is arranged on the surface of the heat dissipation groove for protection, external foreign matter is prevented from entering the controller body through the heat dissipation groove, when the protective net cover needs to be detached, a pressing block is pressed to drive a limiting block fixed to the pressing block to move together, the limiting block moves downwards to break away from clamping connection with the protective net cover, limiting is opened, and the protective net cover is detached. At the moment, the protective net cover can slide to be disassembled, the protective net cover is connected through two rectangular grooves formed in the controller body, grooves are formed in the rectangular grooves to limit the protective net cover, the detachable protective net cover is convenient for a user to regularly take down for cleaning, and the ventilation performance of the net cover is kept.

The utility model discloses an orthosis for preventing underarm scar contracture of a burn patient, which comprises a neck fixing strip, a shoulder lapping piece is fixedly arranged on the side of the bottom end of the neck fixing strip, one side of each first tensioning strip is rotatably connected with a first movable column, an underarm orthosis mechanism comprises an arc-shaped supporting piece, and the arc-shaped supporting piece is fixedly connected with the shoulder lapping piece. Adjusting long holes are formed in the two sides of the inner wall of the arc-shaped supporting piece correspondingly, and two limiting sliding blocks are slidably connected into each adjusting long hole. The armpit orthopedic mechanism is arranged between the first movable columns connected through the first tensioning strip, the limiting sliding block is connected with the arc-shaped filler strip, and the rubber stud is rotationally connected with the arc-shaped contact net piece, so that the orthopedic device is better in ventilation effect, dryness and ventilation of a burn position are guaranteed, recovery of an affected part is promoted, and it is guaranteed that a gap is formed between the arc-shaped supporting piece and the affected part; meanwhile, the arc-shaped supporting piece and the arc-shaped contact net piece generate pressure on the scar, so that the problem of scar contracture is solved while the ventilation effect is guaranteed.

This utility model discloses a suspended air preheater, belonging to the technical field of air preheater technology. The suspended air preheater includes a body, ventilation ducts installed at the top and bottom of the body, a first air inlet and a second air inlet located on both sides of the ventilation ducts, a rotating shaft installed on the ventilation ducts, and a rotor installed on the inner side of the body and rotatably connected to the rotating shaft. The body has mounting grooves at the top and bottom corresponding to the rotor. A sealing assembly is detachably connected to the inner side of each mounting groove. This assembly utilizes an elastic metal sealing body located inside a metal frame, which is subjected to an inward clamping force from a fastening spring installed in an elastic cavity. This causes the first and second sealing lips to fit tightly against the outer wall of the rotor, reducing the gap between the body and the rotor, improving the sealing effect, and employing mechanical cleaning, thus ensuring ventilation while reducing energy consumption.

This application discloses a robot heat dissipation structure and a robot for improving the heat dissipation efficiency of robot joints. The robot heat dissipation structure of this application includes: a shell, a first power module, a second power module, and an air supply assembly; the shell includes a first receiving part and a second receiving part, which are integrally formed or detachably connected, and a communication port is provided between the first receiving part and the second receiving part; the first power module is at least partially received in the first receiving part, and a gap is provided between the side wall of the first receiving part and the first power module; the first receiving part is provided with a first air outlet and an air inlet; the first power module is provided with an air supply assembly near the air inlet; the second receiving part includes a third air outlet, a mounting interface, and a communication port, a dustproof plate is installed on the third air outlet, and a ventilation opening is provided on the dustproof plate; the second receiving part is connected to the second power module through the mounting interface, which has an opening.

This invention belongs to the field of building structure technology, specifically an adaptive ventilation and light-transmitting building partition purification structure. It includes multiple linearly distributed bottom mounting carriers, with a first flow channel and a second flow channel sequentially passing through each carrier. The first and second flow channels are arranged perpendicularly and alternately. An upper movable slot is formed on the bottom mounting carrier above the first flow channel, and a displacement slot is formed on the top of the bottom mounting carrier. A sliding mechanism is provided on the bottom mounting carrier near the displacement slot. In the absence of wind, an electric guide rail drives a undulating rod to actively attract surrounding airflow, ensuring effective ventilation within the building. The electric guide rail is fixedly mounted on the top of the first top mounting carrier. When there is wind, the electric guide rail stops operating via a circuit board, allowing natural ventilation inside the device, facilitating use.

The utility model relates to the technical field of glue production, and disclose a kind of waste gas purification device for glue production, including purification bucket one and purification bucket two, the inside fixed of purification bucket one is equipped with filter screen, the middle part fixed mounting of pollution valve is positioned at the bottom of purification bucket one, the top of purification bucket one is fixedly equipped with bucket cover one, the inside fixed of bucket cover one is equipped with multi-orifice plate, the surface fixed of bucket cover one is equipped with pulse air pipe, the side fixed of purification bucket one is equipped with conduit;Through filter screen, waste gas can be pretreated, remove the impurities in waste gas, reduce the influence on activated carbon, through breathable support component, activated carbon can be loaded, and breathable capacity can be guaranteed, using the pore structure of activated carbon, waste gas can be adsorbed, by connecting pulse air pipe pulse fan, input pulse wind in bucket cover one, filter screen can be cleaned.

The application discloses a photovoltaic energy-saving curtain wall based on a renewable energy system and belongs to the technical field of photovoltaic energy-saving curtain walls, which comprises a longitudinal beam assembly installed on a building outer wall, a cross beam assembly vertically installed on the longitudinal beam assembly, and a positioning frame sealingly installed between the longitudinal beam assembly and the cross beam assembly; a folding photovoltaic power generation module is used to convert renewable solar energy into electric energy; the folding photovoltaic power generation module comprises a fixed strip plate fixedly installed in the center of the positioning frame, two groups of movable strip plates symmetrically installed in the positioning frame relative to the fixed strip plate, and two groups of photovoltaic plates arranged between the movable strip plates and the positioning frame and rotationally connected with each other; the photovoltaic energy-saving curtain wall can control the rotation and folding of the multiple groups of photovoltaic plates according to the needs of building ventilation, illumination and light energy conversion, and can synchronously drive the longitudinal movement of a cleaning flow guide module during the operation process, so that the surface of the photovoltaic plate can be automatically cleaned.

The invention provides an annular double-T ventilation structure and device based on pore anisotropy, and belongs to the technical field of grain storage. The annular double-T ventilation structure comprises an annular main air duct, two symmetrically-arranged air inlets and two T-shaped air ducts which are located in the annular main air duct and are in central symmetry; ventilation holes are formed in the walls of the annular main air duct and the T-shaped air duct, the T-shaped air duct comprises a longitudinal branch pipe and a transverse branch pipe, one end of the longitudinal branch pipe is connected with the air inlet, and the other end of the longitudinal branch pipe extends towards the center and is connected with the transverse branch pipe; a composite ventilation network with the outer ring and the inner T is formed, and the problem of ventilation blind areas in the center area of the bottom of the silo caused by pore anisotropy when wet grains containing impurities are stacked is effectively solved; the invention further provides a wet grain ventilation and cooling device comprising the ventilation structure, the ventilation uniformity of a grain pile can be remarkably improved, the grain temperature can be remarkably reduced, the wet grain ventilation and cooling device is suitable for rapid warehousing ventilation of high-impurity-content wet grains, strict cleaning is not needed, and time and cost are saved.

The utility model provides a protection structure of a trephine controller. The protection structure of the trephine controller comprises a supporting frame, wherein a protection assembly is arranged at the top of the supporting frame; and the protection assembly comprises a protection shell arranged at the top of the supporting frame, a supporting table is arranged on the left side of the bottom of the inner wall of the protection shell, and a controller body is arranged at the top of the supporting table through a fastener. According to the protection structure of the trephine controller provided by the utility model, the protection shell, the iron wire filter screen, the dust filter screen and the heat dissipation fan are arranged, so that the ventilation effect of the controller body can be guaranteed, and dust and impurities are prevented from entering the protection shell to influence the protection shell; and meanwhile, a wear-resistant rope strip is arranged, the cleaning plate can relatively prolong the service life of the dust filter screen, and the heat dissipation effect of the controller is guaranteed.

The utility model discloses an intelligent temperature control type bus duct, and relates to the technical field of bus ducts. The device comprises a bus duct shell and a plurality of mutually insulated conductors arranged in the bus duct shell, the conductors are made of high-purity copper, ventilation openings are formed in the top and the bottom of the bus duct shell, dustproof nets are detachably connected to the ventilation openings, a cooling fan assembly is arranged on one side of the bus duct shell, and a cooling fan is arranged on the other side of the bus duct shell. The heat dissipation fan assembly comprises a plurality of heat dissipation fans, the heat dissipation fans are fixed on the bus duct housing through a mounting rack, and air outlets of the heat dissipation fans face the conductor. According to the intelligent temperature control type bus duct adopting the above structure, the temperature of the conductor in the bus duct can be monitored in real time, the starting, stopping and rotating speed of the cooling fan can be automatically controlled according to the temperature change, intelligent temperature control is realized, the cooling effect is greatly improved, and the stable operation of the bus duct is ensured.

The utility model discloses a coal mine ventilation rescue emergency channel, and relates to the technical field of coal mine ventilation rescue channels, the coal mine ventilation rescue emergency channel comprises a rescue pipeline, the inside of the rescue pipeline is fixedly connected with a plurality of crawling ladders, and the coal mine ventilation rescue emergency channel has the beneficial effects that trapped people can conveniently climb to the upper part of the rescue pipeline through the crawling ladders; through mutual cooperation of a winch, a traction rope, an anti-falling safety garment and a guide wheel, rescue of injured people is facilitated, a third rotating shaft is rotated to drive a worm to rotate, so that a second rotating shaft and a worm gear are driven to rotate, and then a protective net plate is driven to rotate; or a fifth rotating shaft and a second bevel gear are rotated to drive a first bevel gear and a fourth rotating shaft to drive a third rotating shaft, a worm, a second rotating shaft and a worm gear to operate, and the protective net plate is put down; therefore, trapped persons outside the rescue pipeline can conveniently enter the rescue pipeline through the escape exits to escape, or trapped persons climbing up from the lower portion can conveniently escape through the escape exits.

The utility model relates to a two-for-one twister with a dust removal function, which belongs to the technical field of two-for-one twisters and comprises a two-for-one twister body, a dust hood, a dust box, a filter screen box, a dust collecting cloth bag and a transport cart, the dust hood is mounted on the inner wall of the two-for-one twister body and fixedly communicated with a flow dividing pipe, and the flow dividing pipe is fixedly communicated with an opening and closing valve. The two-for-one twister dust collection device is provided with the dust collection cover covering the twisting area, dust in the machining area of the two-for-one twister can be fully collected, the dust collection box body is arranged, the collected dust can be fully filtered, and therefore the dust can be prevented from being pumped into the pump body to cause damage, and the dust collection box body with the larger filtering area is arranged. Compared with a single filter screen body structure, the dust filter screen has a larger filter area, so that dust blockage and influence on the dust removal effect can be effectively prevented, the air blowing cleaning structure is arranged, dust attached to the surface of the filter screen can be quickly blown, cleaned and collected, and the ventilation effect of the dust filter screen can be effectively guaranteed.

The utility model relates to the technical field of coating curing agent production, in particular to a water circulation cooling device for producing a coating curing agent, which comprises a reaction kettle, a conveying pipe is mounted on one side of the reaction kettle, a valve is mounted on the conveying pipe, and a cooling box main body is mounted at the other end of the conveying pipe. An air inlet pipe is embedded in the top end of the cooling box main body, a cooling pipe is mounted on one side of the reaction kettle, the other end of the cooling pipe penetrates through the inner side of the cooling box main body and then extends to the other side in the reaction kettle, and a heat dissipation fan is mounted at one end of the inner side of the air inlet pipe; a dust screen is installed at the end, close to the cooling fan, of the air inlet pipe, and a cleaning and brushing mechanism is installed at the position, located on one side of the air inlet pipe, of the top end of the cooling box body. The dustproof screen is simple in structure and convenient to operate, impurities on the surface of the dustproof screen can be conveniently cleaned and washed, the ventilation effect during heat dissipation and cooling is guaranteed, and the practicability during use is further improved.

This invention relates to the field of pig farming technology, specifically to a pigsty with a function to prevent the backflow of foul air. The pigsty includes a frame, a support plate with multiple slatted floor panels, and side panels on both sides of the frame. A working cavity is located at the bottom of the support plate, and a manure collection cavity is located at the bottom of each slatted floor panel. A main ventilation duct is installed inside the pigsty frame, and a ventilation connection mechanism for controlling the flow of gas into the manure collection cavity is located on one side of the main ventilation duct. This invention uses multiple rotatable adjustable blocks to block the holes in the slatted floor panels in batches, controlling the flow direction of foul air. By creating hollow channels inside the adjustable blocks and installing internal ventilation ducts, ventilation through these hollow channels prevents foul air from rising and spreading into the pig farm. This prevents harmful gases in the foul air from affecting the growth of pigs, thereby reducing the content of harmful gases in the pig farm and lowering the probability of disease in pigs.

The utility model discloses a roof fan convenient to maintain, which relates to the field of fans, and adopts the technical scheme that the roof fan convenient to maintain comprises an air duct, two arc-shaped frames are arranged on the air duct, a safety net is detachably connected between the two arc-shaped frames, a replacement opening is formed in the peripheral wall of the air duct, a cover plate is hinged to the air duct, a first convex block is arranged at the movable end of the cover plate, and a second convex block is arranged at the movable end of the cover plate. A second protruding block is arranged on the air duct, the first protruding block is limited on the second protruding block through a fixing piece, and a rubber ring is arranged on the safety net. When the safety net needs to be cleaned, the cover plate rotates along the hinged position by releasing limitation of the fixing piece on the first protruding block and the second protruding block, the cover plate does not cover the replacement opening any more, and the safety net is detached from the replacement opening to be cleaned. By means of the arrangement, the safety net can be disassembled and cleaned more rapidly, after the safety net is installed, the rubber rings can deform and fill the gaps, and the leakproofness among the air duct, the cover plate and the safety net is ensured.

The utility model discloses a waste residue dissolving and recycling device which comprises a waste residue dissolving and recycling bin body, round rods are fixedly connected to the front face and the back face of the waste residue dissolving and recycling bin body, and fixing frames are arranged on the front face and the back face of the waste residue dissolving and recycling bin body. According to the waste residue dissolving and recycling bin, a solvent is placed in the waste residue dissolving and recycling bin body, then waste residue metal is placed in the waste residue dissolving and recycling bin body, the sealing cover is sealed to the top of the waste residue dissolving and recycling bin body, then the motor is started, and the output end of the motor drives the worm to rotate; the worm drives the worm wheel to rotate, the worm wheel drives the round rod to rotate, the round rod drives the waste residue dissolving and recycling barrel body to rotate, the waste residue dissolving and recycling barrel body can be turned over to fully mix waste residues and a solvent, full dissolving treatment is achieved, and an existing manual mixing and stirring mode is replaced; therefore, the efficient mixing and recycling effect is achieved.

The utility model provides an automatic folding lifting window, which relates to the technical field of doors and windows and comprises a support frame, a folding window group is mounted on the support frame in a sliding manner, and the folding window group comprises a first section of window, a second section of window and a third section of window from top to bottom; a stepping lever is pivoted to the supporting frame, a stepping sliding rod and a horizontal pushing sliding rod are arranged at the upper end and the lower end of the stepping lever, the first section of window is provided with a stepping guide rail, the second section of window is provided with a horizontal moving guide rail, the third section of window is provided with a horizontal pushing guide rail, and the horizontal pushing sliding rod is arranged in the horizontal moving guide rail in a sliding and penetrating mode. A vertical rail and a transverse rail which are communicated with each other are arranged on the supporting frame, and translation idler wheels are arranged on the first section window, the second section window and the third section window and installed in the vertical rail and the transverse rail in a sliding mode. According to the utility model, the first section window, the second section window and the third section window can be horizontally pushed and staggered through the rotation of the stepping lever, so that the folding shrinkage of the folding window group is realized.

The application discloses an energy-saving three-phase motor with high safety performance, which comprises a motor body, a first connecting ring fixedly connected to the right side of the motor body, a second connecting ring arranged at the right side of the first connecting ring, and a plurality of U-shaped connecting plates for fixedly connecting the first connecting ring and the second connecting ring. The outer sides of the first connecting ring and the second connecting ring are jointly provided with an annular groove, and the annular groove is provided with an annular net. A driving shaft is arranged in the motor body, the right end of the driving shaft extends into the first connecting ring, and a plurality of axial fan blades are arranged on the driving shaft. A cleaning mechanism comprises two vertical plates fixedly connected to the inner sides of the first connecting ring and the second connecting ring. In actual use, the motor can realize self-cleaning of the filtering part, the self-cleaning can be performed simultaneously with the operation of the device, and the cleaning is comprehensive.

The utility model relates to the technical field of welding equipment, in particular to an arc welding room which comprises a room body, an opening is formed in one side of the room body, a roller shutter door is arranged at the opening, a clamp used for clamping parts is further arranged in the room body, a first fan is installed on the top of the room body, the air inlet end of the first fan penetrates into the room body, and the air outlet end of the first fan penetrates into the room body. A waste gas collecting cover is installed in the room body, an adjusting assembly used for adjusting the height of the waste gas collecting cover is installed in the room body, a waste gas purifying assembly is installed at the air outlet end of the first fan, a second fan is installed on the side face of the room body, the air inlet end of the second fan is located outside the room body, and the air outlet end of the second fan extends into the room body and is fixedly connected with an air outlet pipe. And an air volume adjusting assembly is arranged on the air outlet pipe. According to the utility model, the collecting height of the waste gas collecting cover can be adjusted through the adjusting assembly, so that the waste gas collecting cover can collect waste gas more comprehensively and thoroughly, the waste gas can be extracted from the room body more comprehensively and thoroughly, and the extraction efficiency of the waste gas is improved.

The application relates to the technical field of fruit tree seedling raising, in particular to a fruit tree seedling raising root-limiting container, which comprises a seedling raising container, a non-woven fabric planting inner cylinder and a moisturizing cover body. The seedling raising container is in a cylindrical shape, the bottom of the seedling raising container is provided with a circular-truncated-cone-shaped supporting part, the non-woven fabric planting inner cylinder is arranged in the inside of the seedling raising container and located on the supporting part, the moisturizing cover body is detachably arranged on the top opening of the seedling raising container, and the moisturizing cover body is provided with a seedling passage in the center. A flow guide groove is formed between the supporting part and the sidewall of the seedling raising container, and the supporting part and the sidewall of the flow guide groove are both provided with water seepage holes. The application combines the ventilation at the bottom of the seedling raising container and the moisturizing at the top of the seedling raising container, reduces soil water evaporation, improves water utilization rate, reduces water supplement frequency, guarantees the ventilation at the bottom of the non-woven fabric planting inner cylinder, avoids root system oxygen deficiency and reduces the risk of root rot.

The utility model discloses a laundry dryer structure, including laundry dryer main part, the laundry dryer main part includes upper drying channel board and lower drying channel board, the both sides of upper drying channel board and lower drying channel board are fixedly connected through the connecting portion, it is hollow structure between upper drying channel board and lower drying channel board, and the inside of laundry dryer main part is formed ventilation pipeline through hollow structure, one side of laundry dryer main part is connected with fan, and heating pipe and detachable filter screen mechanism are fixedly installed in ventilation pipeline, one side of heating pipe is located detachable filter screen mechanism, detachable filter screen mechanism includes filter screen fixed groove and filter screen, and the filter screen is inserted in filter screen fixed groove. The utility model discloses through setting detachable filter screen mechanism, is convenient for to filter screen and is installed and is removed to the user conveniently to filter screen and is washed or is replaced, guarantees the ventilation effect in drying channel, improves the cleanliness of air in drying channel simultaneously.

The utility model relates to a kind of electric power cabinet anti-condensation louver structure, including the window frame being installed on electric power cabinet, the two ends of window frame inside are respectively provided with hydrophobic louver structure and temperature control louver structure, and hydrophobic louver structure and temperature control louver structure are provided with condensing assembly between, hydrophobic louver structure is used to block rainwater and pour into electric power cabinet, temperature control louver structure is provided with electric control assembly, electric control assembly is used to control the opening angle of blade, hydrophobic louver structure is composed of multiple array arrangement's guide louver blade, guide louver blade and window frame are fixedly connected;The utility model is through hydrophobic louver structure and temperature control louver structure, while ensuring ventilation, prevent rainwater and pour into, while temperature control louver structure changes opening angle, changes opening size, when cabinet internal temperature is lower, close louver structure, block inside and outside air exchange, block the entry of external moisture, prevent the generation of condensation, improve practicality.

The utility model discloses a curtain wall ventilator general switch base relates to curtain wall ventilator general switch base technical field. This curtain wall ventilator general switch base, including aluminium alloy main part and ventilation mechanism, aluminium alloy main part's front and back side inner wall fixed mounting has the base, and ventilation mechanism sets up on the base, and ventilation mechanism includes drive assembly, limiting component and linkage component, and drive assembly includes gear, toothed plate and rotation axis, and toothed plate's top fixed mounting has rotation axis, and gear and toothed plate meshed installation, and limiting component includes bottom box, positioning bead card and stainless steel pearl. Through the cooperation of drive assembly, limiting component and linkage component, gear transmission system can provide more stable and accurate motion control, can accurately drive toothed plate, guarantee the opening or close position accuracy of air door board, can rapidly adjust the open -close state of air door board, guarantee that ventilator can be in time start -up or close when needing, thereby ensure the ventilation effect of ventilator.

A modular, bidirectional shock-absorbing and explosion-proof gate, belonging to the technical field of protective equipment, includes: a component unit comprising a valve body with a ventilation channel and a valve cavity in the middle of the ventilation channel. The valve cavity has an opening connecting to the ventilation channel, serving as a valve cavity vent. A valve core is located within the valve cavity and is elastically movable along the airflow direction. The valve core can block the vent in front of the valve cavity along the airflow direction to cut off the airflow to the ventilation channel. This invention, while ensuring ventilation performance, has significant advantages in shock-absorbing performance. In principle, this invention relies on shock wave closure and spring reset. The valve core can move and reset in both directions, effectively blocking the impact airflow on both sides of the gate, achieving bidirectional shock absorption. This invention solves the problem of existing swing-type and hose-type gates being unable to withstand bidirectional shock waves.

This utility model belongs to the field of tent technology, and particularly relates to an inflatable tent, including a frame and a tent fabric. The frame is composed of multiple inflatable columns, each forming a connected inflatable chamber. It stands upright after inflation and collapses after deflation. It also has a preset curvature for forming the top wall frame, meaning the side near the top wall is not horizontal, allowing the center of the top wall to arch and preventing water accumulation. Each inflatable column is equipped with ground pegs and a first guy line, improving installation stability. The tent fabric connects adjacent inflatable columns to form the top wall, bottom wall, and multiple side walls of the tent, each with an entrance and multiple windows. The connected inflatable chambers ensure that the air pressure of each inflatable column is the same, preventing tilting and collapse due to pressure differences or wind, resulting in good stability.

The utility model relates to the field of automobile parts, especially to an automobile insect screen facilitating heat dissipation, which comprises an insect screen plate, the insect screen plate is installed at the front side air inlet of an automobile through an insect screen plate mounting frame, the bottom and top of the insect screen plate mounting frame are respectively provided with a lower mounting hole and an upper mounting hole for mounting the bottom end and top end of the insect screen plate, the utility model sets the insect screen plate apart from the air inlet of the automobile, and the insect screen plate is not attached to the air inlet, thereby forming a multi-directional airflow channel around the insect screen plate, effectively improving the air intake, even if the insect screen plate is full of insects and sundries, the normal air intake of the air inlet of the automobile will not be affected without timely cleaning, the upper air inlet channel, the lower air inlet channel and the gaps on both sides still ensure the ventilation, so that the automobile insect screen has both insect prevention and ventilation functions.

The utility model provides an adsorption type dryer silencer which comprises a silencer body and a filter screen, the filter screen is fixedly arranged in the silencer body, and a cleaning unit is arranged on the silencer body. Dust and impurities in outside air are effectively intercepted and prevented from entering the silencer, so that the interior of the silencer is kept clean, and the stability of the silencing effect and long-term efficient operation of the drying machine are ensured. Meanwhile, due to the arrangement of the cleaning unit, the surface of the filter screen can be regularly cleaned, the problem that the filter screen is blocked due to accumulation of dust and impurities is solved, and the ventilation performance of the filter screen is maintained. In the cleaning process, the collecting unit automatically collects cleaned dust and impurities, the substances are prevented from being brought back to the filter screen by airflow, and the continuous and efficient filtering capacity of the filter screen is ensured.