382 results about "Liquid jet" patented technology

Systems and methods for using a liquid jet apparatus for dental treatments are disclosed. In one implementation, the liquid jet apparatus may include a handpiece configured to deliver a high velocity liquid jet to a desired location in the mouth of a patient. The handpiece may include a positioning member having a channel through or along which the jet can propagate. The positioning member may have a distal end portion configured to be at least partially disposed in a pulp cavity, canal space, or opening in the tooth under treatment. During operation, the jet may impact an impingement surface of the distal end portion of the positioning member and be deflected as a spray through one or more openings in the distal end portion. The liquid jet apparatus may be used for root canal treatments.

The invention discloses water-jet-guided laser cutting equipment and a water-jet-guided laser cutting system, and relates to the technical field of water-jet-guided lasers. The device comprises a dual-wavelength laser assembly, a reflection assembly, a liquid supply assembly and a coupling assembly. The dual-wavelength laser assembly can generate visible laser and invisible laser and coaxially output the visible laser and the invisible laser to the reflection assembly. The reflection assembly is used for refracting the visible laser and the invisible laser to the coupling assembly. The liquid supply assembly is used for supplying guiding liquid to the coupling assembly. The coupling assembly is provided with a nozzle and a coupling body which are connected with each other and used for coupling the guiding liquid, the visible laser and the invisible laser and outputting the laser through the nozzle. Visibly, the visible laser and the invisible laser with the power far greater than that of the visible laser are simultaneously utilized in the water-guided laser, so that the laser power is improved while the visibility of the liquid jet is ensured, the processing efficiency is further improved, and the cost is reduced.

The invention provides a laser coupling assembly, a laser processing device and a laser processing method, and relates to the technical field of laser processing, and the laser coupling assembly comprises a bearing piece which is provided with a first channel and a lens rotatably arranged in the first channel, an included angle is formed between the axis of the lens of the first channel and the extension line where the laser incident direction is located, and the lens is used for reflecting the laser in the first channel and adjusting the position of a light spot formed by the laser on the nozzle; the nozzle is connected with the bearing piece and used for outputting liquid jet flow; the monitoring piece is connected with the bearing piece; the controller is configured to output an adjusting signal according to the relative position; the driving part is in communication connection with the controller to receive the adjusting signal, and the driving part is used for driving the lens to rotate. Thus, the position of the laser is adjusted through the driving effect of the driving part, the laser adjusting precision can be improved, meanwhile, the complexity in the laser adjusting process is reduced, and the laser adjusting efficiency can be improved.

The invention provides additive manufacturing equipment and method for a magnesium alloy liquid continuous injection molding annular part, and mainly relates to the field of metal material additive manufacturing equipment. The invention discloses additive manufacturing equipment and method for a magnesium alloy liquid continuous injection molding annular part, and the additive manufacturing equipment comprises a crucible smelting assembly arranged in an upper vacuum cavity, a liquid injection printing assembly which is arranged in a lower vacuum cavity and communicates with the crucible smelting assembly, and a controller. A three-dimensional motion platform located below the liquid jet printing assembly is arranged in the lower vacuum cavity, and an annular mold with an opening in the top face is arranged at the top of the three-dimensional motion platform. The device has the beneficial effects that the hollow graphite ring piece and the nozzles distributed in an annular array mode are adopted, uniform spraying of magnesium liquid to the annular mold is achieved, the forming efficiency and the quality stability are improved, and the device is particularly suitable for manufacturing large-diameter annular pieces.

The invention discloses a jet flow evaporation cooling system. The jet flow vaporization cooling system for cooling a heat generating unit using a liquid jet flow includes: a heat transfer portion integrally formed with a cooling portion configured to receive the liquid jet flow and an arrangement portion on which the heat generating unit is arranged; an opening portion configured to eject the liquid supplied from the supply portion to the cooling portion; a discharge portion configured to discharge the liquid; and a chamber configured to accommodate the opening portion, the discharge portion, and the cooling portion, and configured not to accommodate the arrangement portion therein, in which the chamber is maintained in a reduced pressure environment, in which the opening portion is configured to eject the liquid to the cooling portion, in which the discharge portion is configured to eject the liquid to the discharge portion, and in which the discharge portion is configured to discharge the liquid to the discharge portion. At least a portion of the cooling portion is inclined, and wherein the liquid is discharged from the discharge portion via the cooling portion.

Provided herein are shaped-charges having curved walls to provide better controllable and improved liquid jet parameters. The shaped-charge comprises a container having a plurality of curved walls for containing a liquid. One or more explosive charges are immersed in the liquid and a detonator channel positioned through the container wall to controllably detonate the one or more explosive charges and from a wedge-shaped liquid jet. Multipoint initiation is achieved using a number of initiation points; a location of one or more initiation contact points with the geometrically-shaped explosive charges; and / or an initiation timing of each of the initiation contact points, including simultaneous initiation or a sequence of initiations. Also provided are related methods of forming liquid jets and attendant applications, including target disruption.

To provide a liquid jet head which is prevented from deteriorating in reliability, and a liquid jet device.SOLUTION: The liquid jet head comprises: a head module including a flow passage opening forming member and a chip; a supply flow passage member that supplies liquid to the head module; an elastic seal member that liquid-tightly connects the flow passage opening forming member to the supply flow passage member; and a fixing member fixing the supply flow passage member to the flow passage opening forming member. A seal region held by the flow passage opening forming member and the supply flow passage member of the seal member overlaps with the chip when viewed in a jetting direction. A dimension in the jetting direction of a portion overlapping with the seal region, of the flow passage opening forming member, is larger than a distance between the seal region and the fixing member when viewed in the jetting direction.SELECTED DRAWING: Figure 5

To provide a head chip that can suppress a driving electrode from being disconnected and is excellent in reliability over the long term, a liquid jet head, a liquid jet recording device, and a head chip manufacturing method.SOLUTION: A head chip according to one embodiment described in the disclosure comprises: a pressure chamber in which liquid is stored; a chip main body having a driving part arranged at a portion facing the pressure chamber; a driving electrode formed on the driving part; and driving wiring formed on the chip main body to connect the driving electrode to external wiring. The driving wiring comprises a first wiring part which has a first region and a second region, connected in an extending direction of the driving wiring to the first region, whose cross sectional areas in a direction orthogonal to the extending direction are smaller than cross sectional areas of the first region, and a second wiring part leading, in a direction crossing the extending direction, at least to the second region.SELECTED DRAWING: Figure 7

The invention provides a spray type water working medium quasi-saturated compression high-temperature heat pump system, and belongs to the field of compression heat pumps. The problems that in the water vapor compression process, the exhaust degree is large, and large-amplitude temperature rise flexible heat supply is difficult to achieve are solved. The system comprises a condenser, an expansion valve, a liquid storage tank, an evaporator, a compressor, an atomization buffer tank, a gas-liquid jet atomizer and a regulating valve, the atomization mode comprises a gas-liquid ejector atomization mode, a high-pressure condensate + atomization nozzle mode or an atomization high-pressure pump + atomization nozzle mode, and is used for preparing atomized liquid drops with the particle size of 50-500 nm for quasi-saturation compression; or single-stage compression is further optimized into a two-stage compression form, so that higher heating temperature and more stable system operation are realized. The micro-nano spraying technology is utilized, the mass fraction of liquid in mixed airflow is always kept between 5% and 10%, heat conversion in the system can be achieved, and through multi-stage continuous phase change cooling, the superheat degree of compressed exhaust is effectively reduced, and compression power consumption is reduced.

Systems and methods for using a liquid jet apparatus for dental treatments are disclosed. In one implementation, the liquid jet apparatus may include a handpiece configured to deliver a high velocity liquid jet to a desired location in the mouth of a patient. The handpiece may include a positioning member having a channel through or along which the jet can propagate. The positioning member may have a distal end portion configured to be at least partially disposed in a pulp cavity, canal space, or opening in the tooth under treatment. During operation, the jet may impact an impingement surface of the distal end portion of the positioning member and be deflected as a spray through one or more openings in the distal end portion. The liquid jet apparatus may be used for root canal treatments.

An ultrasonic control apparatus and method for a liquid jet are provided. An ultrasonic generator is equipped with two sets of ultrasonic transducers arranged perpendicularly to each other, and the two sets of ultrasonic transducers emit ultrasonic waves of a specific frequency. Two sets of reflectors are arranged correspondingly in front of the ultrasonic waves emitted by the two sets of ultrasonic transducers, where a distance exists between the ultrasonic transducers and the corresponding reflectors, two stable standing wave sound fields are formed by adjusting the distance. A liquid jet device is equipped with a nozzle that emits a continuous jet, where the nozzle is located above an intersection of pressure nodes of the two standing wave sound fields, and the two standing wave sound fields act on the liquid jet to adjust jet morphology under the action of acoustic radiation pressures.

The invention discloses a gas-liquid distributor, a gas-liquid distribution method and a multiphase flow reactor, the gas-liquid distributor is applied to the multiphase flow reactor, the gas-liquid distributor comprises a flexible internal member, the flexible internal member further comprises a flexible surface which is arranged above a gas-liquid jet orifice in the reactor and extends along the axial direction of the reactor; the whole flexible surface is in a gradually-changed bent shape and is immersed in a liquid phase of the reactor; the cage-shaped unit is formed by enclosing a plurality of flexible surfaces in the radial direction in the reactor to form a cage-shaped structure; and the space in the reactor is divided into a plurality of cage-shaped units which are uniformly distributed by the plurality of cage-shaped structures. Through the flexible surfaces extending axially and the cage-shaped structure constructed by the flexible surfaces, the size of a bubble phase interface can be effectively improved, and bubbles are distributed more uniformly; according to the invention, a coking part can be guided to a specified position and discharged in time, so that a green coke precursor is prevented from forming small coke particles at the middle upper part in the reactor, adhering to a thermocouple, the wall surface of the reactor or a liquid phase outlet, and even suspending in a liquid phase product to influence the product quality.

The present disclosure relates to abrasive material delivery systems for liquid jet cutting systems. The abrasive material delivery systems can include a valve configured to adjust an inflow of abrasive material into the abrasive material delivery system from a source of abrasive material. The systems can include a chamber downstream of the valve and configured to receive the inflow of abrasive material from the valve. The systems can include a metering component configured to control an outflow of abrasive from the chamber to a cutting head of the liquid jet cutting system. In some embodiments, the systems include a sensor configured to monitor movement of a top surface of a portion of abrasive material within the chamber as the top surface moves through the chamber; and a processing device operably connected to the sensor and configured to determine an abrasive flow rate through the metering component based on a speed of the top surface as monitored by the sensor.

The invention relates to a jet type liquid cooling heat dissipation device for an electronic chip and a working method of the jet type liquid cooling heat dissipation device. The device comprises a chip carrier provided with an electronic chip, a base, a jet flow guide plate, a backflow collection plate, a cover plate and a connector, the base is installed on the chip carrier in a sealed mode, and the jet flow guide plate, the backflow collecting plate and the cover plate are sequentially stacked and mutually connected in a sealed mode and are integrally fixed to the base. A first through hole and a second through hole are formed in the position, above the electronic chip, of the jet flow guide plate, a cooling liquid through hole and a cooling liquid guide hole are formed in the backflow collection plate, and a first cooling liquid connector and a second cooling liquid connector are formed in the cover plate. Compared with the prior art, through the collaborative design of the jet flow guide plate and the backflow collection plate, cooling liquid directly impacts the surface of an electronic chip in a high-speed jet flow mode, and therefore the local heat exchange efficiency is remarkably improved; and meanwhile, a backflow path is optimized, flowing resistance is reduced, high heat exchange performance and low pressure drop are both considered, and the heat dissipation device is suitable for efficient heat dissipation of high-heat-flux electronic chips.

The utility model relates to the technical field of cleaning equipment, in particular to a cleaning tool for cleaning miniature blind holes, which is provided with a supporting cavity, a top plate is arranged above the supporting cavity, a liquid inlet is formed in the supporting cavity, a liquid outlet pipe is arranged on the supporting cavity, the liquid outlet pipe is communicated with the supporting cavity, and supporting fins are arranged on the side wall of the liquid outlet pipe. Cleaning liquid is jetted into the blind hole of the part through the liquid outlet pipe, as the cleaning tool is completely immersed in the water tank of the ultrasonic cleaning machine, ultrasonic waves can directly act on the surface of the part and the interior of the blind hole, and the jetted cleaning liquid can directly wash dirt and impurities in the blind hole of the part, disperse bubbles and break a bubble barrier; the effective permeation and cleaning effect of cleaning liquid are ensured, ultrasonic cleaning can go deep into the fine and tiny positions of the blind hole, a dirt layer is dispersed, emulsified and stripped off through the cavitation effect and the acceleration effect, the dual functions of liquid jet flushing and ultrasonic cleaning are achieved, and the cleaning efficiency and quality are remarkably improved.

The utility model discloses petroleum pipeline dredging equipment, and relates to the technical field of petroleum pipeline dredging, the petroleum pipeline dredging equipment comprises a base and a dredging and cleaning mechanism, and one end of the base is fixedly connected with the dredging and cleaning mechanism. The pretreatment assembly sprays a cleaning solution into a pipeline in advance to soften or dissolve dirt, the device can enter the pipeline conveniently to conduct dredging and cleaning work, meanwhile, the lubricating movement assembly ensures that the device smoothly moves in the pipeline, friction force is effectively reduced through the lubricating liquid spraying device, and the pipeline is protected against damage; the scraper assembly is provided with multiple layers of scrapers and cleaning liquid jet orifices and can powerfully scrape sediments and enhance the cleaning effect, then, the cleaning assembly enables a cleaning brush to be tightly attached to the inner wall of the pipeline through a spring rod system to conduct deep cleaning, and pipeline cleaning rubber can remove stubborn stains without damaging the inner wall of the pipeline. The driving assembly provides a power source for the whole pipe cleaning mechanism, so that the pipe cleaning mechanism can reciprocate or rotate in the pipeline.

Apparatus for cleaning a surface with a liquid jet, the apparatus having: a main housing; a primary fluid conduit having a longitudinal axis and two ends, a fluid-intake end and a fluid-exit end; a gear assembly configured to engage the primary fluid conduit and rotate the primary fluid conduit about the primary-fluid-conduit longitudinal axis; a nozzle connected pivotally to the pivot pin; the hydraulic cylinder mounted to the main housing and configured to move the hydraulic-cylinder rod along a linear path by exerting a unidirectional force upon the first end of the hydraulic-cylinder rod; the hydraulic-cylinder rod positioned within the fluid conduit and the second end of the hydraulic-cylinder rod pivotally connected to the nozzle; and the nozzle configured to pivot about the pivot-pin longitudinal axis as the hydraulic-cylinder rod moves along the linear path.

There are provided a head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing the head chip each capable of achieving a reduction in size in a direction perpendicular to the ejection direction while ensuring the desired ejection performance. The head chip according to an aspect of the present disclosure includes a first ejection section, a jet hole plate arranged at a first side in a first direction of the first ejection section, a return plate which has a plurality of first communication channels configured to individually communicate a plurality of first jet channels and a plurality of first jet holes with each other, and which is arranged between the first ejection section and the jet hole plate in the first direction, and a flow channel plate which has a plurality of first connecting channels individually communicated with the plurality of first communication channels to constitute first return channels together with the corresponding first communication channels, and a manifold communicated in a lump with the plurality of first connecting channels, and which is arranged at a second side in the third direction of the first ejection section.

The invention relates to a device for wrapping a liquid jet (70) widening in a fan shape with an air flow. The device (14; 154, 154; 204) has a housing (16; 204) with a through-channel (18); 206, 206; 252) having an inlet section (28) and an outlet section (30), the outlet section (30) extending to the outlet opening (24) and widening in a fan-shaped manner in the beam plane (34) with gradual approach to the outlet opening (24), and wherein the device has a nozzle carrier assembly (36) which sinks into the inlet section (28) and is surrounded by an air delivery chamber (100), the nozzle carrier assembly has a nozzle carrier part (38) which forms a liquid inlet channel (42) and has a first end region (46), at which a flat jet nozzle (12) can be detachably mounted. In order to further improve the device in such a way that the flat beam nozzle (12) can be mounted on the nozzle carrier part (38) in an operable manner, the invention proposes that the device has an orientation and locking device (78; 172) for orienting and locking the flat beam nozzle (12) in a predetermined rotational position relative to the beam plane (34) of the output section (30). The invention further relates to a liquid dispensing device (10, 150, 200, 230, 250) having such a device and a flat jet nozzle.

Described is a container rotating device for use in handling bulk material, comprising: a frame attachable to a wharf crane or other lifting device; a container rotating mechanism assembled to the frame and configured to selectively engage with the container and rotate the container to dump contents of the container; and the arrangement of liquid jet outlets is mounted on a device for generating liquid jets to suppress dust during tilting operation of the container.

An apparatus for sterilizing a liquid comprises a container having an inlet, an outlet and an interior with an outer wall, and a light source adapted to emit radiation in the ultraviolet wavelength range through the outer wall into the interior, the outer wall being partially transparent. The inlet comprises an opening, positioned in relation to the outer wall of the interior and the light source in order, when a pressure is exerted on the liquid to be admitted through the opening and to be sterilized, to form a liquid jet directed onto the outer wall in a region of the light source, above the latter, and / or to form a liquid film there. The liquid jet impinging on the outer wall may flow down thereon as a thin liquid film in front of the light source and thereby effectively sterilized even with a low penetration depth of the UV radiation.

A method and a device for needleless injection of liquid into a substrate, in particular of a liquid pharmaceutical or cosmetic preparation into a biological tissue, which makes it possible in a particularly advantageous manner to reliably inject a particularly fine liquid jet into the substrate without a significant increase in the static pressure in the liquid during the injection process. According to the invention, this is achieved by first accelerating the liquid received in a liquid container together with the latter to an initial velocity before the movement of the liquid container is stopped again, while simultaneously ejecting the liquid from the liquid container through an outlet nozzle under at least partial retention of its movement. Preferably, the ejected liquid jet is set in rotation about its jet axis before it impinges on the substrate, so that the jet receives a helical movement and thus practically drills into the substrate without splashing away laterally.

The invention relates to the technical field of tailings treatment, and discloses a tailings pretreatment device for mine filling and a treatment method thereof.The tailings pretreatment device comprises a bottom plate, and a stirring assembly and a mounting frame are arranged on the two sides of the top of the bottom plate correspondingly; the stirring assembly comprises a mixing tank for storing tailings, a stirring paddle for stirring and a speed regulating motor for driving the stirring paddle to rotate; the device further comprises a gas-liquid jet flow tailing dynamic suspension mechanism. An air compressor operates to distribute high-pressure air to a two-fluid mixing spray head through a connecting pipe and an annular air conveying pipe, the high-pressure air is sprayed into a mixing tank in an annular jet flow mode, and tailings deposited at the bottom of the tank are subjected to dynamic suspension disturbance; and the liquid flows to the two-fluid mixing spray head through the transfer box, the one-way valve pipe and the liquid conveying pipe in sequence and is mixed with high-pressure gas to form atomized liquid drops, the atomized liquid drops penetrate through gaps of tailings, and the problems that traditional sprayed chemicals are not uniform and the bottom is hardened are solved.

A head chip, a liquid jet head, a liquid jet recording apparatus, and a method of manufacturing a head chip each capable of preventing an occurrence of an unwanted processing residual due to laser processing are provided. The head chip according to an aspect of the present disclosure includes a flow channel member which includes a recess formed of a first laser irradiation trace, and in which a liquid circulates in the recess, and a bonded member which is bonded to the flow channel member so as to close the recess. The flow channel member is provided with a second laser irradiation trace extending along an opening edge of the recess.

The invention provides casting post-processing equipment and a casting post-processing method, and belongs to the technical field of casting processing. The casting post-processing equipment comprises a workbench suitable for bearing a casting body and conveying the casting body to a preset work area; the vibration desanding mechanism is distributed in the vibration desanding area and is suitable for applying vibration force to the casting body so as to realize dry desanding of the casting body; the casting cleaning mechanism is distributed in the casting cleaning area and is suitable for performing liquid jet cleaning on the casting body; and the riser cutting mechanism is distributed in the riser cutting area and is suitable for performing riser sawing on the casting body. The automatic post-processing of dry type sand removal, residual sand cleaning and dead head cutting of a casting can be continuously completed on single equipment, only one-time clamping is needed, the production efficiency is improved, and the procedure turning sequence and manual intervention are reduced.

The utility model relates to the technical field of flushing devices, and discloses a drainage flushing device for liver and gall treatment, which comprises a supporting plate, a drainage barrel is fixedly connected to the middle of the upper surface of the supporting plate, a driven rod is rotatably connected to the middle of the upper surface of the drainage barrel, and a circulation cavity is formed in the lower end of the interior of the driven rod. A plurality of liquid spraying heads are connected to the edge of the lower surface of the driven rod in a penetrating mode, a plurality of brush rods are fixedly connected to the lower end of a rod body of the driven rod, a plurality of brushes are fixedly connected to the outer walls of the opposite sides of the brush rods, and the brushes are attached to the inner wall of the drainage barrel. When the drainage flushing device for liver and gall treatment is used, cleaning liquid in the liquid storage box is pumped by starting the draw-off pump, the cleaning liquid is conveyed into the circulation pipe through the liquid outlet end and conveyed into the circulation cavity in the driven rod through the circulation pipe, the cleaning liquid is sprayed out through the cooperation with the multiple sets of rotary liquid spraying heads, the drainage barrel can be automatically cleaned, and the cleaning efficiency is improved. The cleaning efficiency is improved.

The invention relates to a construction machine (1) for conveying thick material, wherein the construction machine (1) has: a storage space (1) for storing thick material to be conveyed for a conveying operation of the construction machine (1) and a storage container (3) partially delimiting the storage space (2) on the inside, wherein the storage container (3) has a filling opening (4) for filling the thick material to be stored into the storage space (2), and a cleaning device (5) through which a cleaning liquid can flow for a cleaning operation of the construction machine (1), wherein the cleaning device (5) has: a support structure (6) for arrangement on the filling opening (4), and a nozzle carrier (7) which is adjustable relative to the support structure (6), wherein the nozzle carrier (7) has at least one nozzle device (8) for forming a liquid jet of cleaning liquid for the cleaning operation.

To provide a liquid ejecting head and a liquid ejecting apparatus in which a cover can be used in common in accordance with the specification of the liquid ejecting head.SOLUTION: The liquid jet head includes a liquid jetting part Hc for jetting a liquid, a flow channel member 150 communicating with the liquid jetting part Hc, a relay substrate 160 electrically connected to the liquid jetting part Hc, and a cover 170 which houses at least one of the flow channel member 150 and the relay substrate 160 inside and can expand and contract in a height direction.SELECTED DRAWING: Figure 4

A method for providing a fluid cooling system in a high-temperature component comprising the following steps: a) providing a high-temperature component (100) having an outer surface (104); b) creating a plurality of adjacent separate microchannels (110) as open grooves extending into and along at least a portion of the outer surface (104) of the high-temperature component (100), wherein the microchannels (110) are created in the outer surface (104) by means of a technique selected from the group consisting of laser machining, abrasive liquid jet cutting, electrical discharge machining (EDM), milling electrical discharge machining, electron beam drilling, and CNC machining; c) creating one or more coolant passage holes (112) extending from at least one of the microchannels (110) to an interior region (114) of the high-temperature component (100); d) filling the microchannels (110) and the one or more coolant passage holes (112) with a filler material (120); e) applying a first layer of a metallic build-up coating (130, 152) over the outer surface (104); f) creating at least one slot (132) or a set of relatively small passive cooling holes (132) through the first layer of the metallic buildup coating (130, 152), the slot or passive cooling holes (132) extending into at least a portion of one of the filled microchannels (110) formed substantially beneath the slot or passive cooling holes (132); g) removing the filling material (120); and h) applying at least a second coating layer (140, 158, 160) over the first layer.

The utility model discloses a strip steel pickling bath and a strip steel continuous pickling machine, which comprise a pickling bath body and a plurality of spray pipes used for forming acid liquor jet flow, the pickling bath body is a concave square bath body, the plurality of spray pipes are distributed at the bath bottom of the pickling bath body in an array mode, strip steel is arranged above the pickling bath body in a suspended mode, and the spray pipes are arranged on the pickling bath body. The array-distributed acid liquid jet sprayed upwards from the spray pipe to the bottom surface of the strip steel is used for pickling the bottom surface of the strip steel and supporting the suspended strip steel, so that the acid liquid is more uniformly distributed on the surface of the strip steel, the pickling effect of the surface of the strip steel is ensured, and meanwhile, the strip steel is prevented from colliding with the bottom of the pickling tank body; in this way, a supporting stone used in the prior art can be omitted, so that adverse effects of broken stones formed by abrasion of the supporting stone on all parts of the strip steel continuous pickling machine are avoided, the production efficiency is improved, and the maintenance and operation cost is reduced.