49results about How to "Increase the exhaust air volume" patented technology

The invention discloses a constant-air-volume control method for a range hood. According to the method, the number of all internally-arranged gears of an indoor unit is x, and the default initial gearof a high gear air volume interval [ Q1, Q2 ] is x / 2; when the operating gear of an indoor range hood is equal to x and the air volume is smaller than Q1, target air volume is reduced from [ Q1, Q2 ]to [ q1, q2 ], so that the gear is reduced, and noise is reduced; and when the target air volume is in the interval [ q1, q2 ], the number of the operating gear is smaller than x-2, the target air volume is changed from [ q1, q2 ] to [ Q1 and Q2 ], so that the air volume is increased, and the oil fume suction effect is improved. The method has the advantages that a constant-air-volume control method of the range hood is applied to a central flue system; from the point of reducing noise, when the start-up rate is extremely high, the air volume interval is properly reduced, a bit of the oil fume suction effect is sacrificed, so that the noise is reduced; the air exhaust amount of high floors is reduced, so that the flue exhaust power of low floors is increased, and the air exhaust volume ofthe low floors is increased; and meanwhile, the air volume of all the floors is ensured to be balanced and capable of meeting the flue exhaust requirement, so that the use experience of users is good.

The invention discloses an integrated window-type air conditioner. The air conditioner comprises an indoor panel, a cabinet, an evaporator, an indoor fan, a condenser, an outdoor fan, a volute, a compressor and a base plate, wherein the volute comprises a fixed volute and a rotatable volute; the fixed volute forms a cambered surface which semi-encloses the outdoor fan in the cabinet; the rotatable volute is connected to a lower section base plate and rotates by taking a connection position as a rotating shaft; and the lower section base plate is provided with an outdoor vent hole. When the rotatable volute is folded, the outdoor vent hole is enclosed; when the rotatable volute is unfolded, the fixed volute and the rotatable volute form a continuous volute inner surface and heat-exchanged air is guided to flow outwards from the outdoor vent hole. The folded volute occupies a smaller space in the cabinet, so that the overall height of the outdoor side cabinet is reduced and transportation cost is saved. The unfolding degree of the rotatable volute is determined according to the practical indoor condition, so that the air supply volume and air exhaust volume in the cabinet can be adjusted freely according to the practical condition and the running state of the air conditioner is optimized.

The invention discloses a multi-core-driven multi-stage booster combined fire-extinguishing and smoke-controlling device which comprises a carrier. The carrier is provided with a rotating lifting mechanism which is fixedly provided with a combined exhaust blower group, the carrier is also provided with a control system which is connected with the combined exhaust blower group formed by assembling and fixedly mounting six exhaust blowers together, and the six exhaust blowers are arranged up and down and integrally combined in two rows with three exhaust blowers in a row and share an outer air duct, a water supply pipeline and a water mist nozzle. The multi-core-driven multi-stage booster combined fire-extinguishing and smoke-controlling device of the invention has great exhaust air rate in case of a certain volume.

The invention discloses an efficient high blast pressure range hood. The efficient high blast pressure range hood is characterized in that: a draught fan is arranged in a range hood outer shell; the outer shell of the draught fan is connected and sealed with the range hood outer shell; a lead air channel and a mold cavity are connected and assembled to form the outer shell of the draught fan; an air inlet and an air outlet of the draught fan are on the same axis; a motor of the draught fan is fixed in the outer shell of the draught fan; the motor drives a wind wheel connected with a motor shaft to rotate in the mold cavity of the draught fan; a large-sized LED lamp panel is arranged at the lower part inside the range hood outer shell; the interval between the large-sized LED lamp panel and the range hood outer shell forms an air inlet of the range hood; the distance zone between the large-sized LED lamp panel and the range hood outer shell end face forms an air inlet guide zone of the range hood; a guide air channel is arranged in front of an air inlet end of the wind wheel of the draught fan; a plurality of guide plates are arranged at the back of an air outlet end of the wind wheel; the sectional area of an air inlet of the wind wheel is smaller than the sectional area of an air outlet of the wind wheel; the radial section of each blade of the wind wheel is convex, and the convex direction is the rotating direction of the wind wheel.

The invention relates to a large-air-volume volute fan. The fan comprises a volute, a wind wheel and a motor, an air duct is formed in the volute, a coaming of the volute is in an open ring shape, anair outlet is formed in an opening of the coaming, the wind wheel is arranged in the air duct and is in transmission connection with the motor, and a first lead-out plate and a second lead-out plate are arranged on the two sides of the air outlet correspondingly; the second lead-out plate is connected with the other end of the opening of the coaming through an arc transition surface, the horizontal distance between a tangent point between the arc transition surface and a vertical line and the first lead-out plate is 125-155mm, and an included angle between the second lead-out plate and a vertical line is 20-70 degrees; a first arc plate, a second arc plate and a third arc plate are sequentially arranged between the corresponding arc transition surface of the coaming and the first lead-outplate in a tangent transition mode; and blades of the wind wheel are formed by connecting inner arc pieces and outer arc pieces in a tangent transition mode. According to the fan, the structures and sizes of the air outlet, the air duct and the wind wheel are optimized, so that the whole air outlet is reasonably and gradually increased from inside to outside, the exhaust air rate and the exhaust air pressure are increased, and exhausted air can be conveyed to a farther position.

The invention discloses a cotton drying machine. The cotton drying machine structurally comprises a machine box, wherein supporting legs are arranged under the machine box; a power cavity is formed inone end of the machine box, a coil capable of heating after being electrified is arranged in the power cavity, a power mechanism is arranged at one end of the power cavity, a drying cavity is connected to one end of the power cavity, first holes are formed in the inner wall of the drying cavity, and a beating mechanism is arranged in the drying cavity; an impurity cavity is formed outside the drying cavity, exhaust cavities are formed at the upper part of the impurity cavity, sliding grooves are formed in the exhaust cavities, external sliding rails are arranged at one ends of the sliding grooves, and first baffles are arranged in the sliding rails; and a discharging opening and a feeding opening are formed in the upper portion of the machine box, and a turning cover is arranged on the feeding opening. The cotton drying machine has the beneficial effects that the beating mechanism can stir cotton, so that heating is more evenly, the drying efficiency is improved; the beating mechanismcan also beat caked cotton lumps after water absorption, so that cotton is separated, meanwhile, the cotton is fluffed out, and the cotton quality is improved; and cotton discharging is controlled bymanually controlling opening and closing of exhaust holes, and the cotton can be discharged from the discharging opening only under the condition that the cotton is completely dry and fluffy.

The invention provides an organic gas recovery modular assembly and a coating machine waste gas treatment system. The organic gas recovery modular assembly is characterized in that an organic gas concentration sensor is arranged on the exhaust pipeline, connected with a drying oven, of the organic gas recovery modular assembly, so that the air supply amount and the air exhaust amount of the drying oven can be dynamically adjusted according to the detected concentration of organic gas in a production device, on the premise that the concentration of the organic gas in the drying oven is maintained within an allowable concentration range required by the design process, the power consumption of operation of a fan is reduced as much as possible, the heating load required by an oven heater is reduced, energy is saved, and the operation cost of the system is reduced.

The invention relates to a pulley drive structure of a window type air conditioner, comprising two fans respectively arranged at the inside of a room and the outside of the room; an electric motor is arranged at one side of the space of the outside of the room, an electric motor rotating shaft at one side of the electric motor is connected with fans at the outside of the room, and the other end of the electric motor is connected with a fan at the inside of the room by a belt roller arranged on the electric rotating shaft; in the space at the outside of the room, a plurality of shaft blocks are arranged on the other side which is in correspondence with the electric motor, and the shaft blocks are fixed on the bottom surface of a one-piece box; the rotating shafts are arranged on a plurality of shaft blocks, one end of the rotating shaft is connected with the fans at the outside of the room, the other end thereof is connected with fans at the space at the inside of the room by the other belt roller arranged on the rotating shaft, and the two belt rollers are connected by a belt. In the invention, only one electric motor is needed to be installed to drive the four fans at the outside and inside of the room by the belt rollers, thus reducing the number of electric motors, expanding internal space of the air conditioner, improving air output of the fans and giving full play to the performance of the fans.

The present invention provides a squirrel-cage-shaped motor driven water injection pump load start pressure-stabilizing water injection apparatus. The apparatus comprises a water injection pump and a squirrel-cage-shaped motor that drives the water injection pump, and the apparatus further comprises a smart vector converter, a redundant pressure controller and a pressure sensor. According to the apparatus, magnetic field oriented vector control is carried out on the squirrel-cage-shaped motor by using the smart vector converter, so that output torque of the squirrel-cage-shaped motor at a low speed is increased, and a water injection pump load start can be implemented with a small starting current; real-time monitoring of a pressure change of water injection is performed by a pressure sensor; the redundant pressure controller carries out closed-loop control on a water injection pressure signal and frequency output of the smart vector converter, and the water injection pressure is adjusted by changing a rotation speed of the motor; and an independent fan is added at a tail of the squirrel-cage-shaped motor, so as to increase the exhaust volume of the squirrel-cage-shaped motor at a low speed and reduce the temperature of the motor.

The invention provides a residential kitchen and bath exhaust system control device and method. The device comprises a kitchen public flue, a toilet public flue, a host and a host air pipe, and also comprises a kitchen air volume main control valve, a kitchen flow distribution valve, a toilet air volume main control valve and a toilet flow distribution valve, wherein the kitchen air volume main control valve is used for controlling the exhaust air volume of the kitchen public flue; the kitchen flow distribution valve is used for controlling the exhaust air rate of a range hood air pipe of each kitchen; the toilet air volume main control valve is used for controlling the exhaust air volume of the public flue of the toilet; the toilet flow distribution valve is used for controlling the exhaust air rate of a ventilator air pipe of each toilet; and the host is used for determining a target operation frequency based on the working parameters of the residential kitchen and bath exhaust system control device and providing power for the residential kitchen and bath exhaust system control device at the target operation frequency. The technical problem that a kitchen and a toilet exhaust air independently, and in the use peak period, smoke exhaust of middle and lower floors is unsmooth in the prior art is solved.

The invention relates to a volute fan for a smoke exhaust ventilator. The volute fan comprises a volute, a double-output-shaft motor, a first centrifugal wind wheel and a second centrifugal wind wheel. A partition plate is arranged inside the volute. The volute is divided into a first wind cavity and a second wind cavity through the partition plate. A second output shaft of the double-output-shaftmotor is provided with a first transmission gear. A second transmission gear and a rotating shaft are arranged in the second wind cavity. The first transmission gear is engaged with the second transmission gear. The second transmission gear is in transmission connection with the inner end of the rotating shaft, and the outer end of the rotating shaft is in transmission connection with the secondcentrifugal wind wheel. Compared with a volute fan in an existing smoke exhaust ventilator, the double centrifugal wind wheels are adopted in the volute fan for blowing air, and therefore the air exhaust amount of the volute fan is increased and finally the smoke exhaust efficiency of the smoke exhaust ventilator is improved. Moreover, an oil discharging hole is formed in the bottom of the volute,oil cannot be left inside the volute easily, cleanliness and sanitation of the volute fan are guaranteed, peculiar smells are avoided and meanwhile the cleaning difficulty of users is lowered.

The invention relates to the technical field of compressor parts, in particular to an anti-inversing device for a two-stage compressor. The anti-inversing device comprises a main shell, a first-stage cavity and a second-stage cavity are formed inside the main shell, an air inlet runner communicated with the first-stage cavity is arranged on the left side wall of the main shell, and an air outlet runner communicated with the second-stage cavity is arranged on the outer wall of the lower end of the main shell. According to the anti-inversing device for the two-stage compressor, a fixing sealing frame internally provided with an elastic sealing cover is fixed inside an air conveying runner, a connecting limiting sheet on the right side of a through hole is transversely arranged on the fixing sealing frame to limit and control the sealing cover, after the air pressure reaches a certain degree, the connecting limiting sheet automatically turns over to enter a turnover containing groove, and therefore the exhaust air rate is increased; a flow slowing cavity internally provided with a metal piston is arranged on the right side of the second-stage cavity, and therefore the air and piston impact is greatly increased, damage of the inner wall is avoided, the service life is prolonged, the anti-inversing performance is greatly improved, and air flow flowing is more balanced.

The invention discloses a centrifugal fan with an impeller structure. The centrifugal fan with the impeller structure comprises an impeller bin and an impeller assembly, wherein the impeller bin has certain inner space; and the impeller assembly is arranged in the impeller bin and is rotatably connected with the impeller bin, so that the impeller assembly can rotate relative to the impeller bin. The centrifugal fan with the impeller structure is characterized in that the impeller bin comprises a bottom wall, a plurality of air outlet side walls and a plurality of air pressing side walls; the air outlet side walls and the air pressing side walls are arranged at the edge of the bottom wall; the air outlet side walls and the air pressing side walls are arranged alternately and are successively connected end to end; a plurality of air outlets are formed in each air outlet side wall; and a V-shaped air pressing structure which is projected to the inner side of the impeller bin is arranged on each air pressing side wall. According to the centrifugal fan with the impeller structure, exhaust air rate and air pressure are high under the condition that the power of an input motor is not changed, air throwing is stable, turbulent flow is less, meanwhile, noises generated during running are further reduced, user experiences and endurance power are improved, and the market application prospect is good.

The invention discloses an exhaust assembly of a water-drive and non-electric exhaust fan. The exhaust assembly comprises an exhaust shell and an exhaust inner cylinder. The lower end of the exhaust inner cylinder is cylindrical, and the upper end of the exhaust inner cylinder is conical. The upper layer of the exhaust inner cylinder is provided with a fixing blade which is connected with the exhaust shell, and the lower layer of the exhaust inner cylinder is provided with a guide wheel blade which is connected with the exhaust shell. An impeller is driven to rotate through circulating of circulating fire fighting water in a ship body. The shape of concave blades in a turbine shell is improved, and therefore the conversion rate of water kinetic energy is improved, exhaust wind pressure is improved accordingly, and the ventilation distance of air in the ship body can be effectively increased by 30 meters.

The invention relates to an overall ventilation system of a microwave oven. The overall ventilation system comprises vent holes, a throughflow fan, exhaust grids, a vapor flue, a heat radiation flue, air inlet grids, a heat radiation opening and a heat radiation fan, wherein the exhaust grids are used for providing exhaust holes; the heat radiation flue consists of an air inlet flue and an air exhaust flue; the air inlet grids are used for providing air holes; the heat radiation flue is integrally formed with the vapor channel; the exhaust flue is positioned between the air inlet flue and the vapor channel; the exhaust flue and the vapor channel are both communicated with the exhaust holes; the air inlet flue is communicated with the air inlet holes; the throughflow fan is used for sucking vapor from a cooking cavity through the vent holes and used for discharging the vapor outside the microwave oven; external air is introduced into a machine chamber from the air inlet holes, the air inlet channel and the heat radiation opening; hot air in the machine room is discharged outside the microwave oven from the heat radiation opening, the exhaust channel and the exhaust holes. As the vapor channel and the heat radiation channel are integrated, and the channels are separated, the overall ventilation system is relatively compact in structure, small in noise and high in exhaust air rate, and due to modularization of the channels, the overall ventilation system is universal.

The invention belongs to the technical field of information equipment waterproofing, especially information equipment with good waterproofing performance. Aiming at the poor waterproofing effect of the existing information equipments, the following options are proposed: including hosts, a housing and a heat sink, the front surface of the shell is provided with a display screen, and the outer surface of the display screen is provided with a blue light shielding plate, the upper surface of the host computer is provided with a keyboard and a touch pad, the host computer is internally provided with a circuit board, the lower surface of the heat dissipation seat is provided with a base, and the interior of the heat dissipation seat is provided with an exhaust fan; grooves are arranged at both sides edge positions of the lower surface of the heat dissipation seat, and four sets of jacks are arranged at both sides edge positions of the upper surface of the base. In the invention, each waterproof part cooperates to form a multiple waterproof structure, which greatly improves the waterproof effect of the equipment, has good heat dissipation property of the information equipment, and can meet different use requirements by changing the placement angle.

A range hood and its series fan system, control method, connectors, and fan system, the series fan system for range hoods includes: a first fan; a second fan; a connector, the two ends of the connector are respectively connected to the second The air outlet end of the first fan and the air inlet end of the second fan; the connecting piece includes a control switch, which is used to detect the fluid characteristics of the detection points in the connecting piece, and control the working state of the second fan according to the fluid characteristics, so that the second The blower opens with the opening of the first blower, and closes with the close of the first blower; the connecting piece also includes a throat, the opening cross-sectional size of the throat is smaller than the opening cross-sectional size of other parts of the connecting piece, and the detection point is located between the throat and Between the outlet ends of the first fan. The technical solution provided by the invention can simplify the installation method of the second fan without changing the first fan, and the two fans can work in linkage, and can effectively improve the working efficiency of the entire series fan system.

The invention discloses a cooling fan for an engine, a cooling system for the engine and engineering machinery. The cooling fan for the engine comprises a hub, a first fan blade component and a second fan blade component, wherein the first fan blade component comprises a plurality of first fan blades; the first fan blades are mounted on the hub and extend in a radial form along the radial direction of the hub; the second fan blade component comprises a plurality of second fan blades; the second fan blades are mounted on the hub and extend in the radial form along the radial direction of the hub; and distances from head ends of the first fan blades to the axis of the hub are more than the distances from the head ends of the second fan blades to the axis of the hub. The cooling fan for the engine provided by the invention has the advantages of complete air exhausting area coverage, strong air exhausting capacity, simple structure and small occupied space.

The invention provides a smoke exhaust and a series fan system and a control method thereof and a controller and a fan system. The series fan system for the smoke exhaust comprises a first fan, a second fan and a connector, wherein two ends of the connector are correspondingly connected to an air outlet end of the first fan and an air inlet end of the second fan; the connector comprises a controlswitch; the control switch is used for detecting the liquid property of a detecting point in the connector, controlling the working state of the second fan based on the fluid property in order to start the second fan as the first fan starts and stop the second fan as the second fan stops; the connector further comprises a throat shaped port; the section of an opening of the throat shaped port is less than that of openings of other parts in the connector; and the detecting point is positioned between the throat shaped port and the air outlet end of the first fan. According to the technical scheme, the system has the advantages that the mounting mode of the second fan is simplified on the premise that the firs fan is not changed; and moreover, the two fans can be interlinked to work, so thatthe working system of the whole series fan system can be effectively improved.

The invention provides a temperature-controlled purification device with superimposed air volume, comprising: a first box body, the first box body is provided with a first air inlet and a first air outlet arranged on the top of the first box, and the inside of the first air inlet is installed with Filter screen, the first box is equipped with an oxygen generator for inputting oxygen and the first row of fans aligned with the first air outlet; the second box is detachably stacked on the first box, and the second box is opened There are a second air outlet and a plurality of second air inlets, the position of the second air inlet corresponds to the position of the first air outlet, the inside of the second air outlet is installed with a filter, and the second box is equipped with a second The second exhaust fan at the air outlet and the refrigeration device for cooling or heating the air; and the air volume amplifying device for increasing the suction air volume of the second air inlet are installed at the second air inlet. The invention solves the problems that the traditional air purifier has poor comfort of purified air and few applicable occasions.

The invention provides a cross-flow belt type sludge dryer. The sludge dryer includes a tank body. The tank body has a plurality of drying layers arranged in parallel from top to bottom. The drying layers are metal mesh-shaped conveying belts with opposite running directions. Materials are sequentially transferred from an upper drying layer to a lower drying layer by gravity. Drying air enters cross-flow air pipes of each drying layer from the upper part of the tank body through an air duct, and the low-temperature high-humidity air that is obtained after drying is discharged from a pluralityof exhaust outlets below the dryer. The bottom layer of the dryer is a sweeping layer, and the dried materials and fallen materials of each drying layer are swept to a material outlet at the lower part of the tank body of the dryer. A feeding port is in the upper part of the dryer. After semi-dry sludge is granulated, the sludge is fed into the dryer, and a granulator is located above the feedingport of the dryer, and is roll-type shearing type device. The invention provides the belt type sludge dryer in which the semi-dry sludge with a moisture content of 68-72% can be dried to obtain driedsludge with a moisture content of 10-20%, heat of incineration of the dried sludge can satisfy heat required by the dryer, and the heat efficiency is high.

The invention relates to a wet acetylene automatic unloading calcium carbide crushing explosion-proof dehumidification ash-free dust removal system. The system comprises a rolling door and an exhaustfan arranged in an unloading area. A rolling door controlling device used for controlling the rolling door to roll and unroll is arranged on the upper part of the rolling door. The rolling rood controlling device, a power source, a motor driving the exhaust fan, and a speed regulating switch of the motor form an electric circuit. When the rotating speed of the motor increases, the rolling door controlling device is suitable for increasing opening of the rolling door. When the rotating speed of the motor decreases, the rolling door controlling device is suitable for decreasing the opening of the rolling door. The lifting height of the rolling door is controlled by the rolling door controlling device, and therefore the lifting height is in direct proportion to the rotating speed of the motor, and the rotating speed of the exhaust fan is in direct proportion to the lifting height of the rolling door.

The invention relates to an air flow control method, device and equipment and a storage medium, and belongs to the technical field of air treatment.The air flow control method includes the steps that the standard pressure intensity of each area is set according to the cleanliness degree and the geographic position of each area; wherein the areas comprise a polluted area, a semi-polluted area and a clean area; the standard exhaust air rate of the corresponding area is set according to the standard pressure intensity, and the actual exhaust air rate of each area is kept equal to the corresponding standard exhaust air rate; the pressure difference between the actual pressure intensities of the two adjacent areas communicated through the door is obtained in real time; judging whether the pressure difference is smaller than a first preset value or not; and if yes, the actual exhaust air rate of the area with the lower standard pressure intensity is increased. The present application has an effect of reducing the possibility that germs in a low-cleanliness region enter a high-cleanliness region.

The invention discloses a multi-functional solar comprehensive utilization device which comprises a hollow light-transmition and heat insulation cylinder, a solar heat collection system, a solar illumination system and a micro wind power generation system, wherein a photovoltaic power generator is installed in the solar illumination system, and the indoor ventilation quantity is increased and theventilation effect is improved by the chimney effect generated in the hollow light-transmition and heat insulation cylinder, thereby the invention reaches the purposes of ventilation, dehumidification, cooling and harmful gas exhaust, supplies the thermal energy in various modes of hot water, hot wind and the like, also fulfills multiple functions of double-power generation, double light source illumination, indoor ventilation driving, indoor temperature, humidity and air quality regulation and the like, realizes effective reuse of solar resources, has the advantages of little investments, easy combination with a building, and convenience of installation and popularization, ingeniously realizes high integration of multiple functions through compact structure and reasonable design, can be used in both the south and the north in four seasons, and avoides repeated investment and resource waste.

The invention relates to an outer-ring-folded type exhaust hood wind wheel comprising a round ring, blades, a shaping ring, a drive plate and installation grooves. The wind blades are arranged on the round ring. The shaping ring is fixed to the side edge of the round ring. The installation grooves are distributed at the edge of the drive plate. The blades are arranged in the installation grooves. The round ring comprises top faces, inclined faces and bottom faces, the bottom faces are located below the top faces, and the bottom faces, the inclined faces and the top faces are integrally formed by bending a plate and are in a toothed ring shape. Each blade is in an arc sheet structure in the manner that the corresponding top face and the corresponding inclined face are jointly stamped. The top end of each blade is connected with the corresponding top face. One end of each blade extends into the circumference defined by the bottom faces. According to the outer-ring-folded type exhaust hood wind wheel, the round ring is in the tooted ring shape, so that the length of each blade is increased; and besides, the diameter of the round ring is constant, and therefore the overall exhaust air rate and the overall rigidity are improved.

The invention provides a manufacturing method of an axial flow turbo-charging fan. The axial flow turbo-charging fan is low in volume, large in air output, volute-free, multi-air-duct and ultra-low-noise, and the volume of the axial flow turbo-charging fan cannot be increased along with increase of the air output. The structural design of a multi-air-duct internal-absorption axial flow turbo fan is most obviously characterized in that: an internal space of a turbo is fully utilized; more than two layers of fan blade rings are arranged; each layer of fan blade rings is formed by ring-like distribution of angular fan blades in a tilting state, wherein the cross section of each angular fan blade is shaped like a right angle substantially; air is absorbed from the outside and bottom of the turbo in an internal-absorption mode and then discharged vertically; and over 50 percent of the quantity and effective area of the fan blades are increased. In the field of a fan-top smoke exhaust ventilator, the fan has the advantages that: a volute is not used, the volume is low, and the air output is large, so that the resonation vibration noise of a cavity of the volute cannot be generated; a large lateral air intake space is not required to be formed between the side of the fan and an outer cover; the width and depth of an upper cover of the smoke exhaust ventilator are quite small; axial flow air draft and discharge modes are kept, so that wind resistance is small, and ventilation efficiency is high; and the fan is light-weight, and materials are saved.