48results about How to "Break the seal" patented technology

The invention discloses a mechanical-hydraulic double-acting release rotary tail pipe hanger, and belongs to the technical field of manufacturing downhole tools for oil and gas well cementing operations in oil and gas development. The mechanical-hydraulic double-acting release rotary tail pipe hanger comprises a short drill pipe, an upper joint, a release mechanism, a double male joint, a male and female joint and a lower joint. The short drill pipe, the upper joint, the double male joint and the lower joint are connected in a threaded manner from up to down sequentially. The mechanical-hydraulic double-acting release rotary tail pipe hanger further comprises a loading mechanism comprising a hanger set hydraulic cylinder, a light-load bearing, conjoined twin slips, a conjoined twin cone, a heavy-duty bearing and a central pipe. The hanger set hydraulic cylinder, the light-duty bearing, the conjoined twin slips, the conjoined twin cone and the heavy-duty bearing are arranged on the central pipe from down to up sequentially. The central pipe is connected at the lower end of the male and female joint. The heavy-duty bearing is arranged between the male and female joint and the conjoined twin cone. By the aid of the mechanical-hydraulic double-acting release rotary tail pipe hanger, a tail pipe can rotate when the a tube pillar enters, after the hanger is set and is separated from a releasing release, the slips and the bearings bear the hanger, and functions of rotating and well cementing of a heavy-duty tail pipe is realized.

The invention discloses a power supply stable on-off control circuit and method used in a sea surface floating device. The circuit comprises a switching unit, the input end of the switching unit is connected with a power supply, the output end of the switching unit is connected with the input end of a voltage stabilizing conversion circuit, and the output end of the voltage stabilizing conversion circuit is connected with a microcontroller and other electricity utilization units of the device. The switching unit is composed of a gravity switch and an electronic switch which are connected in parallel. The microcontroller detects on-off of the gravity switch through a detection circuit and controls on-off of the electronic switch through a driving circuit. According to the control circuit and method, the device is electrified when being vertically arranged in a positive mode and is powered off when being vertically arranged in an inverted mode by exceeding a certain time, on-off of the device can be conveniently achieved, and in addition, the situation that an interface is additionally arranged and consequently, the sealing performance of a shell of the device is damaged is avoided.

The invention relates to a single battery and an expansion test method thereof, the single battery comprises a battery cell, an insulating film, a shell and a cover plate assembly, the insulating filmwraps the battery cell and is accommodated in the shell, the shell is provided with at least one opening, and the cover plate assembly covers the opening of the shell; the outer surface of the insulating film is coated with a marker, and when the battery cell expands to the outer surface of the insulating film to be in contact with the inner surface of the shell, the marker can be printed and dyed to the inner wall of the shell to form an imprint. According to the single battery and the expansion test method thereof, the hard expansion degree of the battery cell can be obtained by measuring the area of the imprint. The area of the air pressure acting surface can be obtained by detecting the area of the maximum imprinting area of the inner wall of the shell when the air in the shell is seriously extruded, so that the maximum air pressure in the shell can be estimated, data guidance is provided for the size design of the shell and the battery cell, and the situation that the sealing performance of the shell is damaged due to the fact that the air pressure in the shell is too high is avoided.

The invention discloses a high-airtightness anti-explosion shell for a fuel gas detector. The anti-explosion shell comprises a sealing shell (1) made of transparent ceramic, wherein an air exchange hole (101) is formed in the sealing shell (1), a valve (4) is arranged at the air exchange hole (101), a protecting cover (3) is arranged on the inner wall of the sealing shell (1), a spring (5) is arranged between the tail of a motor (2) and the protecting cover (3), and a rubber pad (102) is fixed at one end, close to the exterior of the sealing shell (1), of the exchange hole (101). The high-airtightness anti-explosion shell has the beneficial effects that the rubber pad is arranged at the exterior of the air exchange hole, and when the fuel gas detector needs to be ventilated, the air enters the sealing shell through a ventilating hole, the air exchange hole, a ventilating trough and the protecting cover; when the fuel gas detector needs to be sealed, the valve is abutted with the rubber pad to seal the ventilating hole and the ventilating trough, so that the airtightness is guaranteed.

This invention provides a folding non-frame balcony window, comprising upper beam lower beam and several sashes, each of which is composed of glass plate, two side clamps, suspension gear structure and lower gear structure. Wherein, the suspension gear structure comprising central axis, pulley block and fixing plate, and its sliding rail consists of the upper rim of the first wheel bearing in pulley block located in the two medial wall of upper beam, the lower rim of second wheel bearing and sloping rim contacting the pulley block; lower gear structure consists of central axis, the third wheel bearing and fixing plate; back of side clamps forms a cavity located hinge and rivet, and the adjacent windows are loose jointed via upper and lower hinges located in the cavity. The invention has the advantages of convenient switch and long service life.

The invention discloses an air supply device for a respirator mask, the air supply device comprises an air valve, and the air valve is provided with a change-over switch mechanism. An air bypass module is further arranged, and the air bypass module is provided with a bypass change-over switch. The bypass change-over switch controls switching of opening of one of an air bypass channel of the air bypass module or the air valve. According to the air supply device, direct switching between ambient air and a compressed air bottle is more convenient through a linkage switching mechanism, and the sealing performance of an air exchange system is prevented from being damaged. Potential safety hazards are eradicated.

The invention relates to the technical field of agricultural irrigation equipment, and particularly relates to a loss-prevention agricultural canal irrigation device. The loss-prevention agriculturalcanal irrigation device can prevent foreign matter such as gravel and gravel from damaging a gate, has the positive effects of prolonging the service life of the gate and ensuring the sealing performance of the gate, has practical significance and popularization value, and can generate good economic benefits in an expected mode. The loss-prevention agricultural canal irrigation device comprises agate body, a driving device and a fixing device, wherein a gate plate which can ascend and descend in the length direction of the gate body and forms a moving pair with the gate body is arranged on the gate body; the driving device is used for driving the gate plate to ascend and descend; the fixing device is used for fixing the gate plate; a sliding block which forms a moving pair with the gate plate is arranged at the bottom end of the gate plate; a base is arranged on the gate body; the cross section of the sliding block and the cross section of the base are both in a wedge shape; and the sliding block is matched with the inclined surface of the base.

The invention discloses a mobile terminal, the mobile terminal comprises a sound chamber shell and a metal insert, wherein the sound chamber shell is provided with a groove and the metal insert is located in the sound chamber shell through injection molding, and the groove on the sound chamber shell and a mainboard of the mobile terminal form a loudspeaker sound chamber of the mobile terminal through surrounding. A first surface of the metal insert, facing towards the loudspeaker sound chamber, is provided with a first contact terminal, and a second surface of the metal insert, back to the loudspeaker sound chamber, is provided with a second contact terminal; the first contact terminal protrudes from a third surface of the sound chamber shell, is located in the loudspeaker sound chamber and is connected with the mainboard; and the second contact terminal protrudes from a fourth surface of the sound chamber shell and is connected with an antenna circuit board of the mobile terminal. Themobile terminal provided by the invention is beneficial for implementation of mutual optimization of audio effects and antenna performance.

The invention discloses a power supply stable on-off control circuit and method used in a sea surface floating device. The circuit comprises a switching unit, the input end of the switching unit is connected with a power supply, the output end of the switching unit is connected with the input end of a voltage stabilizing conversion circuit, and the output end of the voltage stabilizing conversion circuit is connected with a microcontroller and other electricity utilization units of the device. The switching unit is composed of a gravity switch and an electronic switch which are connected in parallel. The microcontroller detects on-off of the gravity switch through a detection circuit and controls on-off of the electronic switch through a driving circuit. According to the control circuit and method, the device is electrified when being vertically arranged in a positive mode and is powered off when being vertically arranged in an inverted mode by exceeding a certain time, on-off of the device can be conveniently achieved, and in addition, the situation that an interface is additionally arranged and consequently, the sealing performance of a shell of the device is damaged is avoided.

The invention discloses a stable explosion-proof shell for a fuel gas detecting instrument. The stable explosion-proof shell comprises a seal housing (1) which is made from transparent ceramics, the seal housing (1) is provided with a scavenging port (101) on which a valve (4) is arranged, and the inner wall of the seal housing (1) is provided with a protective cover (3); a spring (5) is arranged between the tail part of a motor (2) and the protective cover (3), and one end of the scavenging port (101) adjacent to the seal housing (1) is fixed with a rubber cushion (102). The stable explosion-proof shell provided by the invention has the beneficial effects that a rubber cushion is arranged on the outer part of the scavenging port (101), and air passes through a vent hole of the rubber cushion, the scavenging port (101), a vent groove and the protection cover and then enters the seal housing when ventilation is needed; furthermore, when the seal is demanded, the valve is adhered to the rubber cushion to seal the vent hole and the vent groove in a matching way, so as to ensure the leakproofness.

The invention discloses an ejector pin sealing type gas blasting machine which comprises an inner pipe, an inner pipe filling cavity, an ignition mechanism, an inner pipe inflating mechanism and an outer pipe, wherein the inner pipe filling cavity is formed in the inner pipe; two ends of the inner pipe are hermitically connected with a first sealing inner cover and a second sealing inner cover respectively; the outer pipe is arranged on the outer layer of the inner pipe; a first sealing outer cover and a second sealing outer cover are hermitically connected between the inner pipe and the outer pipe; the ignition mechanism and the inner pipe inflating mechanism are mounted on the first sealing inner cover or the second sealing inner cover; an outer pipe inflating mechanism is mounted on the first sealing outer cover or the second sealing outer cover; a sealing cavity between the inner pipe and the outer pipe is an outer pipe filling cavity; the inner pipe filling cavity is filled with supercritical oxygen and carbonaceous organic materials; and the outer pipe filling cavity is filled with liquid gasification-liable substances such as liquid carbon dioxide or liquid nitrogen. The ejector pin sealing type gas blasting machine has the advantages of low manufacturing cost, high reaction material mixing uniformity, high heat release efficiency, high transportation safety and high blasting power.

A water cooling motor air leakage detection method disclosed by the present invention belongs to a leakage detection method of the sealing structural parts. By a machine sealing cavity leakage detection step, a motor cavity leakage detection step, a coolant gallery leakage detection step and a leakage detection test ending step, the air leakage detection of a water cooling motor is finished, thereby guaranteeing that before the water cooling motor is used, the sealing performances of the parts satisfy the usage demands, reducing the overhauling and reworking probability after the water coolingmotor is used, and reducing the maintenance cost.

The invention discloses a heliostat address setting method, device and system. By adopting a close-range wireless communication mode, address setting instructions are issued to multiple heliostats, and according to different intensities of wireless signals received by all the heliostats, a heliostat address setting data sheet is made. All the heliostats receive the address setting instructions, detect the intensities of instruction signals and query the heliostat address setting data sheet to obtain address values corresponding to the intensities of the instruction signals, and the address values are used as addresses of the heliostats. By adopting the method, a user does not need to manually open an electrical cabinet for dial-up setting, the leakproofness of the electrical cabinet is prevented from being damaged, and accordingly the service life of a hardware module in the electrical box is prolonged. Address setting of multiple heliostats can be completed at the same time, one-by-one setting is not needed, the address setting efficiency of the heliostats in a heliostat field is improved, the workload of construction personnel is greatly reduced, and the project progress is accelerated.

The invention provides an air supply purifying device and an air supply purifying method. The air supply purifying device is used for purifying sealed air supply of an air sealing assembly in a methanol synthesis system, and comprises an air supply purifying first module and an air supply purifying second module, wherein the air supply purifying first module and the air supply purifying second module are in alternate operation, or the air supply purifying first module and the air supply purifying second module are in simultaneous operation; each of the air supply purifying first module and the air supply purifying second module comprises a cooler and a coalescer; an inlet of each cooler is communicated with an outlet of a fresh air supply compressor; an inlet of each coalescer is communicated with an outlet of the corresponding cooler; each coalescer separates out entrained impurities in sealed supply air; an outlet of each coalescer is communicated with a sealing cavity formed by the air sealing assembly. The technical scheme solves the problem that the air sealing assembly cannot stably operate for a long period due to methanol and paraffin entrained in the air in the prior art.

The invention relates to the technical field of environmental equipment, and provides atmospheric environment detection equipment. The equipment comprises a rack, wherein the rack is provided with an annular groove; a negative pressure fan which is arranged on the rack, and a suction opening of the negative pressure fan is located in the annular groove; a working pipe, which is arranged in the annular groove in a sliding mode and provided with a working cavity, and the working cavity is provided with an inlet; a lifting table, which is arranged on the rack in a lifting mode and located above the annular groove; a sampling pipe, which is arranged on the lifting table and stretches into the working cavity after the lifting table ascends and descends; and a clamping and capping mechanism, which is arranged on the lifting table and located beside the sampling pipe. By means of the technical scheme, the problems that in the prior art, a sampler cannot well collect gas at different heights, the collection efficiency is low, the collection range is limited, the collected gas cannot be well stored, the service time is long, and the cost is high are solved.

The invention provides a valve with a filtering device, and solves the problem that in the prior valve, sundries accumulate at the bottom of the valve, so that a valve secondary seal is corroded and broken, and the valve loses the function. The valve comprises a valve body [2]; the valve body [2] is provided with a water inlet [3] and a water outlet [1]; and the water inlet [3] and the water outlet [1] of the valve are provided with filter screens [4] for sealing the water inlet [3] and the water outlet [1]. The valve can effectively solve the problem of the functional failure of the valve caused by the sundries and effectively reduce the production and maintenance cost.

The invention discloses a photovoltaic power station rainproof combiner box, which comprises a box body, the box body is in the shape of a cuboid, and the upper and lower ends of the box body are both openings, and the openings of the upper end surface and the lower end surface of the box body are respectively provided with upper seals with the same structure. The four corners of the box body are provided with connectors, which are connected with the upper and lower seal plates on the upper and lower sides of the box body through the connectors. One end of the connector extends out of the first boss, and the first boss The end face of the connecting piece is flush with one side of the box body, and the other end of the connector is provided with a box installation hole. Out of the sealing plate slot, the box body slot and the sealing plate slot are connected and fixed by fasteners and connectors; there is also a drain hole on the connector at the upper end of the box, and one end of the drain hole is located on the surface of the sealing plate slot. The other end is located on the side close to the installation hole of the box body, no welding is required, the structure is simple, and the processing difficulty is reduced.

The invention discloses a thimble sealed type trigger and a cracking device. The thimble sealed type trigger comprises a shell, a filling cavity, an ignition mechanism and an air inflation mechanism. The inside of the shell is the filling cavity, and the shell is connected with the sealed ignition mechanism and the air inflation mechanism. The filling cavity is filled with supercritical oxygen and carbonaceous organic material or elementary substance with reductibility. The air inflation mechanism comprises an air inflation hole, a valve rod and an air inflation valve seat. The middle of the air inflation hole is an air locking cavity, and the valve rod is movably installed in the air locking cavity through a thread structure. An ejector header and an ejector header sealed ring are installed at the top of the valve rod, and the ejector header is sleeved with the ejector header sealed ring. The thimble sealed type trigger and the cracking device have the advantages that manufacturing cost is low, mixing uniformity of reaction materials is high, heat releasing efficiency is high, and conveying safety is good.

The invention relates to the field of lithium battery production, and discloses a battery liquid injecting hole cleaning method and a cleaning device. The cleaning method comprises the following stepsof: determining a cleaning area on a battery cover plate, wherein the cleaning area is an area, which does not comprise the liquid injecting hole, in the periphery of the liquid injecting hole; determining a rotation angle of a first lens and a rotation angle of a second lens in a laser cleaning machine according to the cleaning area, wherein the first lens is inclined towards the right lower side, and the second lens is inclined towards the right upper side, the first lens is opposite to a laser head of the laser cleaning machine and is positioned at the right upper side of the second lens,the laser cleaning machine further comprises two motors which are separately connected with the first lens and the second lens for separately driving the first lens and the second lens to rotate. A cleaning method provided by the invention can clean an electrolyte solution in a peripheral area of the liquid injecting hole, does not clean the liquid injecting hole during cleaning, prevents the laser from breaking seal inside a battery; and the cleaning method is simple to operate, and is safe and reliable.

The invention discloses a cloud intelligent control method based on an industrial embroidery machine. According to the method, a cloud intelligent control module is adopted to transmit and use embroidery patterns; a cloud transaction control module is adopted to provide information and products of embroidery machine manufacturers and achieve direct transactions of purchasers and vendors. A cloud intelligent control system based on the industrial embroidery machine comprises a microprocessor, a communication module, a camera and a microphone, wherein the microprocessor is connected with the camera and the microphone; and the microprocessor is connected with the embroidery machine through the communication module. According to the scheme, an embroidery machine cloud transaction platform is created for a first time, industry resources are combined and regulated, the company marketing and purchase cost can be reduced, and multi-win-win situations can be achieved. The sealed state of a conventional research industry can be broken, and a completely novel idea and scheme are provided for solving industrial research reports. By adopting the scheme, conventional industry transformation andupgrading and interconnection can be accelerated, national fundamental policies at present can be met, and the method and the system can be widely applied to the field of communication.

The invention belongs to the related technical field of 3D printing, and discloses a rapid cooling device and system for powder bed 3D printing. The rapid cooling device comprises a basic base plate, a variable base plate and a cooling water tank, a groove is formed in the basic base plate, the cooling water tank is arranged in the groove, the variable base plate is arranged on the cooling water tank and serves as a 3D printing forming table top, circulating cooling water is introduced into the cooling water tank in the 3D printing process, and the variable base plate is cooled, so that timely and rapid cooling of a formed part in the printing process is achieved. The invention further discloses a 3D printing system using the cooling device. By means of the rapid cooling device and system, forming and cooling are conducted at the same time, grain size increasing in the forming process is restrained, element distribution uniformity is kept, and the strength of the formed part is improved.

The invention relates to the technical field of temperature control equipment, and provides a temperature detection device, storage equipment, a refrigerator and a storage chamber temperature control method. The temperature detection device comprises a sealed cavity and a pressure sensing module arranged in the cavity; the cavity is used for storing a phase change medium capable of generating phase change; and the pressure sensing module is used for collecting pressure in real time in the process that the phase change medium in the cavity changes from the first phase to the second phase. According to the temperature detection device, the storage equipment, the refrigerator and the storage chamber temperature control method, whether the target temperature is reached in the storage chamber or not can be judged in time according to the pressure change generated on the pressure sensing module when the phase change medium configured in the device generates phase change, and the wrong influence of external factors of the storage chamber on temperature detection is avoided; and energy loss is caused.

The embodiment of the invention provides a gun type camera. The gun type camera comprises a camera body; a partition piece is arranged in the camera body, the partition piece divides the inner space of the camera body into a first cabin and a second cabin located behind the first cabin, the first cabin is a closed cabin, and a wire penetrating opening used for allowing an external cable to penetrate is formed in the side wall of the second cabin; an optical device group is arranged in the first cabin. According to the gun type camera provided by the embodiment of the invention, the internal space of the camera body is divided into the first cabin and the second cabin by the separation piece, the first cabin is a sealed cabin adopting a sealed design, and the optical device group is arranged in the first cabin, so that the optical device group can be well isolated from external air. A threading opening of a camera tail wire is formed in the side wall of the second cabin, and in the field installation process of the gun type camera, in order to conveniently penetrate an external cable, the second cabin can be opened for threading operation.

The invention discloses a heliostat address configuration method and system. The method comprises the following steps that: S1, each heliostat in a heliostat field receives a positioning light beam projected by a heat absorption tower of the heliostat field, and measures an incident angle of the positioning light beam; S2, an address comparison table is inquired according to the incident angles to determine the heliostat address of each heliostat, wherein the address comparison table is a corresponding relation table of the incident angles and the heliostat addresses; and S3, each heliostat is configured according to the determined heliostat address, and configuration information is fed back to an upper computer. According to the heliostat address configuration method, the uniqueness of the light beam angle and the particularity of the solar photo-thermal mirror field are creatively combined through the long-distance high-precision light beam, the method is used for large-scale mirror field heliostat address setting, large-scale automatic address configuration is achieved, and the configuration efficiency is greatly improved.

The invention discloses a vacuum pressing plate for product packaging, which includes an antistatic aluminum foil bag, a product carrier, a desiccant package and an auxiliary pressing plate, and the desiccant package is placed at the center of the upper end surface of the product carrier loaded with products , the desiccant package and the product carrier are filled in an antistatic aluminum foil bag, the auxiliary pressure plate is pressed on the upper surface of the antistatic aluminum foil bag, a pneumatic smoothing mechanism is set on the auxiliary pressure plate, and the auxiliary pressure plate is pressed down During the process, the piston push block is compressed inward, so that the air stored in the negative pressure generating chamber can be dispersed to the air diffuser holes on the outer wall of the telescopic pressure plate through the exhaust channel, and the antistatic aluminum foil bag will be compressed in a telescopic pressure after being sprayed out through the air diffuser holes. The plate is centered and smoothed outward, so that the upper surface of the antistatic aluminum foil bag is kept smooth and flat. Vacuum effect, reduce packaging time.

The invention relates to a special hydraulic station for testing the function of a hydraulic reversing valve and a testing method thereof, comprising: an oil source control branch, on which an oil tank and a pneumatic pump are arranged, and the output ends of the oil source control branch are respectively connected to downstream pressure control The input ends of the branch circuit and the safety control branch circuit; the output ends of the downstream pressure control branch circuit and the safety control branch circuit are respectively connected to the input ends of the hydraulic reversing valve test branch circuit and the total oil return branch circuit, and the output of the total oil return branch circuit The output end of the hydraulic reversing valve test branch is connected to the pilot valve and the main valve of the hydraulic reversing valve to be tested, and the pilot valve of the hydraulic reversing valve to be tested and the oil return port of the main valve are both After testing, the oil return branch is connected to the input end of the total oil return branch to form a circulation system; it also includes an air source control branch, the input end of the air source control branch is connected to the driving air source, and the output end is connected to the pneumatic pump. Used to ensure the normal operation of the air pump. The invention can be widely used in the field of underwater production control.

The invention discloses a cabinet used for installing a power transmission line image monitoring terminal. The cabinet includes an upper cover, an inner cover, and a bottom box, the upper cover is made of an insulating material, and the inner cover and the bottom box are made of metal materials; the bottom of the inner cover is sealingly connected with an opening of the upper end of the bottom box, so that a sealed chamber for mounting the image monitoring terminal is formed in the bottom box; the inner cover is provided with an equipotential contact sheet and at least one main conducting linefastener used for locking the cabinet on a power transmission conducting line; one end of the equipotential contact sheet is embedded in the inner cover and protrudes into the sealed chamber, and theother end extends toward the power transmission conducting line and can be in contact with the power transmission conducting line, so that the equipotential contact sheet can be used for connecting the power transmission conducting line with a ground wire of the image monitoring terminal, and so, the image monitoring terminal is equipotential with the power transmission conducting line; and a connection between the equipotential contact sheet and the inner cover is sealed. The invention also discloses an installation method of the power transmission line image monitoring terminal. The cabinetand the installation method solve the technical problems that installation is inconvenient and unsafe, and protection of monitoring terminals is poor in the prior art.

The present invention relates to an all-optical current transformer with an integrated isolation circuit breaker, which includes a primary side sensitive unit, fittings, a suspension insulator and a T-shaped flange. Fixed at one end of the suspension insulator, the outer side of the arm perpendicular to the central axis of the T-shaped flange is fixedly connected with the flange of the isolating circuit breaker, and the arm where the central axis of the T-shaped flange is located is connected to the high-voltage busbar The back of the ring structure of the fitting is fixedly arranged on the inner side of the arm perpendicular to the central axis of the T-shaped flange. The all-fiber-optic current transformer integrated with the isolation circuit breaker involved in the present invention can realize the integration of the isolation circuit-breaker and the all-fiber-optic current transformer, and is suitable for the integrated and intelligent requirements of a new generation of intelligent substations.

The invention discloses a tunnel joint waterproof structure and a waterproof construction method thereof.The tunnel joint waterproof structure comprises a concrete arch hole A and a concrete arch hole B. A combined splicing mechanism is fixedly installed between the opposite sides of the concrete arch hole A and the concrete arch hole B. A water source drainage mechanism is arranged in the concrete arch hole A and the concrete arch hole B; by adopting a physical compression mode, the rubber product has a certain deformation quantity under the action of external force, and the other generated deformation equivalent can be used for supplementing no matter where a convex-concave structure appears on the rubber leather cushion A or the rubber leather cushion B in real time, so that a gap between the rubber leather cushion A and the rubber leather cushion B after the rubber leather cushion A and the rubber leather cushion B are in contact can be ignored, and the rubber product is prevented from being damaged. The waterproof structure effectively solves the problems that after an existing waterproof structure fixes a concrete arch hole A and a concrete arch hole B through glue, the gap between the concrete arch hole A and the concrete arch hole B is coated with a waterproof material, the concrete arch hole A and the concrete arch hole B are separated after the glue is weathered, and a waterproof coating falls off.