CN1044336C - Pyrolytic deposition in a fluidized bed - Google Patents
Pyrolytic deposition in a fluidized bed Download PDFInfo
- Publication number
- CN1044336C CN1044336C CN92105230A CN92105230A CN1044336C CN 1044336 C CN1044336 C CN 1044336C CN 92105230 A CN92105230 A CN 92105230A CN 92105230 A CN92105230 A CN 92105230A CN 1044336 C CN1044336 C CN 1044336C
- Authority
- CN
- China
- Prior art keywords
- particle
- bed
- base material
- pressure
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The accurate control of thermal decomposition carbon coated on workpieces in a granule fluidized bed is realized by the detection of the different between the pressure above the bed layer and the pressure below the bed layer or the pressure at the lower part of the bed layer. The measurement of the discovered pressure difference can really represent the size of a bed layer in the coating device; the size of the bed layer is an important factor of the required characteristics of coated material. The size of the bed layer is adjusted correspondingly to the change of the measured pressure difference; therefore, the size of the bed layer can be easily kept constant basically, or the pressure difference is changed step by step according to programs previously weaved. In the two cases, the adjustment is carried out by particle addition in the bed layer or the speed rate change of particle discharge; therefore, accurate characteristic of coating layers can be obtained; for example, thickness has very small tolerance.
Description
The application relate to certain material for example the carbon of thermal decomposition be deposited on process above the base material that flies in grain fluidized bed.Relate in particular to the method and apparatus that very carefully to control thermal decomposed deposition, especially be deposited the situation of the density of material less than the showy grain density that constitutes fluid bed.
Be with hydrocarbon gas or steam for a long time, or the steam of certain other carbonaceous material carry out thermal decomposition thermally decomposed carbon is deposited on the base material.It has been recognized that for many years, the surface area that can be used to deposit in the unit volume fluid bed has very big influence for the feature of the thermally decomposed carbon that is deposited, therefore the characteristic of the thermally decomposed carbon of actual deposition as requested the mat size of carefully controlling fluid bed regulate, this is in the U.S. Patent No. 3 of investing Bokros etc., generally indicate in 399,969.This patent is pointed out, in the auxiliary bed of fine particle (its granularity is tens of or hundreds of microns), carry out thermally decomposed carbon when applying for for example having size about 5 millimeters or the big workpiece of bigger those, can rely on control to control deposition process with respect to the available deposition table area of the coating room volume at actual deposition place.
Authorize the U.S. Patent No. 3,977,896 of Bokros and Atkins and narrated a kind of improved method, can deposit the significant thermally decomposed carbon coating of thickness with this method, this coating has uniform crystallinity in whole thickness range.This method adds applicator with small size particle on the one hand, then regulates the flow by the inert gas up of particle passing away on the other hand, the feasible particle that has applied (on granularity, become big) remove from coating room with the speed of control.So just can make total deposition table area of coating room inside keep more stable, thereby obtain above-mentioned uniformity.
In US Patent No, after 3,977,896 announcements, issued US Patent No to Brooks, 4,456,012, it discloses a kind of improved fluid unit that is used to apply this big workpiece.This equipment is that the bed of forming with suspended particulate links together, wherein, used a overflow pipe, be placed in the extreme higher position of height required in the coating room, thereby the fluid bed size is kept on volume necessarily with plane on the qualification fluid bed with overfall.Preferably is with the overflow pipe of top seal, and its overfall is towards the inboard, but not towards the center line of application chamber.Upwards blast the inert gas qi of chong channel ascending adversely stream of capacity in order to avoid the dust that significant quantity arranged descends together with coated particle nationality gravity discharges by this overflow pipe.Also be the US Patent No of issuing to Brooks, 4,594,270 have been disclosed when a kind of bigger workpiece suspends also mat thermal decomposition coating in this class fluid bed, can remove the equipment of particle at desired height and position from bed.This patent has pointed out to adopt a probe tube that can slide in vertical direction, and it can change position (preferably can control it in the outside of stove) makes its opening can be adjusted to the required upright position of sampling arbitrarily.Can control the flow of inert gas in the probe tube again, make and optionally to make particle discharge in required upright position from fluid bed.
Though above-mentioned these patent disclosures the feasible method of control thermal decomposed deposition in fluidized system, determine that bed is very difficult in the long-pending size of the real surface of arbitrary given time, if be not impossible work; And complicated day by day along with coating procedure, be necessary and can control more accurately the characteristic of the thermally decomposed carbon that deposited.Therefore people are seeking more perfect control method always.
The purpose of this invention is to provide and a kind of thermally decomposed carbon or similar substance are deposited on the method and apparatus that floats on grain fluidized bed base material, wherein the real area on fluid bed surface is all accurately determined at arbitrary given time of deposition process.
Another object of the present invention provides and a kind of thermally decomposed carbon or similar substance is deposited on the method and apparatus that floats on grain fluidized bed base material, and wherein the character of Chen Ji thermally decomposed carbon is accurately controlled.
The present invention draws, by measure one we find can authentic representative the variable of bed size, promptly (a) is inner or just be lower than the poor of a certain pressure that gives pressure and (b) a certain position, bed top on the allocation in fluid bed place at fluid bed, just can be more accurately control on the base material that floats, deposit the process of thermally decomposed carbon or similar substance in grain fluidized bed.If the soot formation of significant quantity is arranged in the fluid bed applicator, the suitable location of gaging pressure is below generation cigarette ash place, and is perhaps as mentioned below in its outside.Accurately measured behind the pressure at these two positions, can make the surface area correspondence in the bed do this pressure differential and appropriate change.The so little variation of bed size can be by changing the speed that particle is discharged from bed, or change the speed that particle adds bed, or change these two kinds of speed simultaneously and realize.The thermally decomposed carbon that the result deposited or the characteristic of other material can accurately obtain control, for example guarantee that the degree of crystallinity height of deposition thermally decomposed carbon is even, perhaps by the feature of the thermally decomposed carbon of compiling and editing the routine change deposition.For example can deposit carbon, and deposit the carbon of another kind of feature in its later stage in the incipient stage of coating procedure with certain feature.
Fig. 1 is the fluid unit schematic diagram that is used for depositing the thermal decomposition coating on the workpiece that suspends together with the bed particle, and its part is a profile.This equipment has embodied various characteristics of the present invention, and comprises the subsidiary body that controls its operation.
Fig. 2 is the schematic diagram that the part in Fig. 1 equipment is got another kind of embodiment.
Fig. 1 represents a suitable fluid bed coating equipment 20, and it comprises the shaft 22 with garden cylindrical outer cover 24, and its inside then is coating room, between it and the garden cylindrical outer cover generally every with edge thermosphere 25.Coating room by thin sleeve pipe 26 and down lining 28 wrap and close.Following lining 28 cooperates with the bottom of thin sleeve pipe 26, and for coating room provides the bottom surface 30 of a taper, the heart has a vertical channel 32 therein, and this passage is preferably coaxial with the sleeve pipe 26 with cross section, garden.Though this class applicator there is no the restriction on the size, general available applicator, the diameter of its sleeve pipe 26 are not more than 30.48 centimetres of (1 feet), particularly internal diameter and are about 15.24 centimetres (6 feet) or less.The gas that produces suspension effect upwards flows in passage 32, enters coating room.
There is a ring-type lining upper end of boiler tube 24, and it is sleeve pipe 26 usefulness that centers.The wall of the exhaust passage 36 of coating room is exactly to go up lining 34, and it extends downwardly in the stove, plays a part outlet opening is slightly dwindled, and has the lower surface 37 of butt taper.The suspension of leaving the heat of fluid bed applicator is used with applying with gas and is gone up exhaust passage 36 by this, and a conduit that is fit to 38 discharges of flowing through.
Applying operation is to realize by set up the fluid bed that is made of subparticle (granularity is less than 1 millimeter) in the coating room bottom.As shown in the figure, this fluid bed extends to the taper space of being contained by the upper end 30 of descending lining.One after fluid bed forms, and one or more workpiece 45 to be coated (for example repairing circular flap body or locking sheet (oc-cluder) with heart valve) are then by last exhaust passage 36 bed of packing into.In a single day these workpiece just are among the bed by airflow flowing upwards and are supported in the fluid bed.Particle in the bed and workpiece to be coated are heated to required application temperature with regard to mat to the heater an amount of electric energy of input.The coating room temperature inside is then measured and control, i.e. electricity consumption temperature measuring equipment (for example thermocouple) or optical temperature measurement device with present technique field institute universal mode.If adopt the latter, then observe it by an observation window (not shown).
Used ascending air is the mixture of fluidisation with inert gas and carbonaceous material gas during coating, for example methane, ethane, propane, butane, acetylene, propylene or its mixture that this carbonaceous material gas can be known with people in this area, or the gaseous state of other carbon containing or volatile suitable material.If the material that require to apply is not 100% thermally decomposed carbon, but certain alloy alloy of carborundum and thermally decomposed carbon for example, then with the suitable silicon sources material of aequum for example in the admixture of gas of methyl trichlorosilane introducing fluidization-coating usefulness.Represented a hydrocarbon source 46 that has flow control valve device 48 among Fig. 1, it is other to be an inert gas (for example argon, helium or nitrogen) source 50, and it also has suitable flow control valve device 52.These two kinds of gases flow into total pipeline 54, feed the vertical channel 32 of lining 28 under the seat then.
Regulate the total flow of using gas up by fluidization-coating of coating room, make fluidized bed region occupy the bottom of sleeve pipe 26 (as shown in Figure 1) substantially.The updraft that feeds from eye has formed annular airflow at the lower area of fluid bed, and the part of fluid bed is exactly the space that the taper surface 30 of lining 28 is contained in illustrated device.Fine particle moves up in the central area, generally moves down along the annular airflow outer rim then.But also can adopt other device, for example flat coating room, admixture of gas then by in the fluidization technology general porous sintered plate or perforated plate enter.
Particle can select to such an extent that make the density of its density greater than deposited material in the bed.If what will deposit is thermally decomposed carbon or the thermally decomposed carbon that contains small amount of carbonized silicon, then the density of particulate material should be about 3g/cm at least
3, 4～5.5g/cm preferably
3The particle of available refractory oxides for example, such as aluminium oxide, aluminium oxide-silicon oxide (mullite) and compact zirconia, for example density is greater than 5g/cm
3ZrO
2, the about 3.2g/cm of density
3Mullite.When this class particle is coated in bed, along with its granularity increases, gross density will diminish gradually.In general, those more tiny uncoated particles trend towards being sink to the bed bottom, and the density that coating is thicker composite particles less than normal generally then upwards floats, and resides in bed top.Use the granularity of particle to should be about 1000 microns (μ m) or less.Be preferably, the particle mean size of the particle that adds in applying operation is not more than about 400 microns, can be 300 to 425 microns particle, should be greater than 500 microns and apply the particle of discharging when operating.
In order to remove particle, install a discharge conduit 56 that the opening of suitable diameter is arranged on its top from bed.The penetrable whole linings 28 down of conduit 56, perhaps shorter on length, below coaxially be connected in a bore hole, this bore hole is positioned at the top of a passage 56a who gets out, makes the conduit path stretch out one section from the taper surface 30 of lining down.Discharge conduit 56 and be preferably in top closure, and tap is opened on sidewall.The length of conduit 56 can make its top terminate in conical surface and paste the vertical wall part, but for about 10.16 centimetres (4 inches) of internal diameter or less applicator, conduit 56 preferably stretches out more than the taper surface, and the extension elongation maximum is no more than 2.54 centimetres.The material of discharge conduit 56 that extends to coating area is with suitable refractory material, for example graphite or mullite.
Enter collecting chamber 62 by the particle mat gravity that aperture 57 enters conduit 56 to lower edge material outlet canal 60 by fluid bed, the vessel that are placed wherein graduated cylinder and so on are collected.The total amount of the particle of having removed at any time or/and volume can mat range estimation or with load sensor 65 mensuration.To the collecting chamber pressurising, the fine adjustment of pressurising is to rely on flow control valve assembly 68 is carried out far distance controlled by suitable source of the gas 66 usefulness inert gases, its detailed lazyly repeats hereinafter.Inert gas is by collecting chamber the flowing up by discharge nozzle 60 and discharge conduit 56 of pressurising, be not only as qi of chong channel ascending adversely stream and fall into collecting chamber with the dust that prevents significant quantity, and play a part the speed that accurate adjusting particle is removed by fluid bed, this is in U.S. Patent No. 3, have in 977,896 more specifically and discuss.Increase the pressure of the gas in the collecting chamber 62, the flow velocity that inert gas makes progress will increase, and particle will reduce or discharge fully to stop from the speed of bed discharge as a result.Reducing its gas pressure continuously or periodically then makes discharge rate increase.
Have been found that the fluid bed size that coating deposition takes place may be accurately to control the most important parameters of the thermally decomposed carbon feature that is deposited in coating room.Have now found that measure fluid bed pressure at both sides poor (Δ p) even variation be an effective way of the very little variation of perception bed size.Therefore, by detect bed pressure at both sides difference be the bed bottom or just locate below the bed certain a bit with the pressure differential of certain point more than the bed, and take corresponding measure at itself and departing from of required pressure difference value, can in the whole process of primary coating, realize accurate control to process.Find that also a mode that realizes this detection is exactly two pressure sensing mouths of installing in the coating room zone.In the illustrated embodiment, the pressure sensing mouth of top is provided by the long-channel 70 that runs through lining 34; Similarly, the long-channel 72 of lining 28 is provided the pressure sensing mouth of below by running through down.The mouth 72 of below is suitable for second volume area that is in bed or is lower than bed, preferably is in bottom 25% volumetric region of bed.The mouth 70 of top and below mouthfuls 72 respectively mat pipe 74,76 be connected with pressure sensor 78 measuring the pressure of these two mouth positions, and make pressure differential.If be necessary, can load onto the readable pressure differential of optional range estimation.Though best adopts pressure sensor 78, other suitable device for pressure measurement for example liquid manometer also can use.For prevent pressure measxurement mouth and its passage by dust, carbonaceous material or and particle stop up, in these two measuring systems, all keep the suitable qi of chong channel ascending adversely of inert gas at a slow speed stream (not shown).Hole 70 and 72 qi of chong channel ascending adversely stream come to pipeline 74 and 76 injecting gas, and its flow is constant.Pressure when operating beginning to applying each time (taking into account qi of chong channel ascending adversely stream separately this moment) is measured, and applies the reference point of operating as this time.
The signal that is produced by pressure sensor 78 is sent to a control module 86 by circuit 84.The signal that this control module 86 will be received at that time compares with the value that has programmed in its holder, sees the operator scheme that whether is keeping required.If not, then control module with regard to the suitable adjusting of priming.Adjusting to the bed size is to add the speed of bed by changing particle, or changes the speed that particle is removed from bed, or changes the two speed.Therefore, control module links to each other with a suitable circuit 88, and electricity or the pneumatic signal that waits is sent to particulate feeder 40 with regard to circuit by this; Control module links to each other with the another kind of liny road 90 that is connected to control valve 68 simultaneously.This control valve is determining particle to discharge in the conduit 56 and 60 inert gas flow up.Set particulate feeder and make that it is more convenient with constant in fact speed with the particle feeding applicator of desired particle size.In the case, the change (adjusting) that the bed size is done corresponding to institute's measuring pressure difference then is that mat increases or reduces the speed that particle discharges from bed and carries out.
Below the beaker 63 that guarantees that particle removes from fluid bed by required amount, be preferably in to accept the whereabouts particle, adorn a load sensor 65.The suitable circuit 94 of this load sensor mat links to each other with control module, and the signal of representing beaker and particle gross weight is provided.Control module can more time dependent weight signal, thereby measures accurate amount that each required time is removed particle at interval in (for example per second or every part are planted).Adopt load sensor 65 can determine accurately whether the adjusting of doing by particle removal passage flow up for nitrogen (for example adjusting in certain short time) can reach desired effect.As a result, just may regulate nitrogen gas pressure immediately, perhaps to N
2The length and the frequency of the gas supply cycle that flow rate is lower are regulated, and the removal speed of particle is fine-tuning to desirable value, so that the difference of detected two pressure is accurately maintained the numerical value of program composition in the specified time interval of primary coating operation.
Any suitable electronic controller all can adopt, for example controller that can buy from Inotek/AnalogDevices, or the UDC-900Multi-Pro of Honeywall, or IBM286 computer and Control E.G. software.Control module 86 preferably can carry out program composition makes and keeps different bed conditions in primary coating operating period that commercial controller has this class method establishment characteristics.Control module preferably should comprise a microcomputer, and it can program feasible, for example, adopts bigger bed size at certain commitment that once applies operation, makes the thermally decomposed carbon deposition slower, thereby makes the turning inwall of workpiece apply preferablely.This program reduces the bed size gradually in the later stage of operation then, and the speed of thermally decomposed carbon deposition is increased.If necessary, can carry out other change the bed size is increased when applying EO gradually closing on, adapting to situation about just increasing at coated workpiece quality, or for a certain former thereby change the physical characteristic of institute's deposited coatings on a specific base material.For example, may need different crystalline characteristics, for specific purposes even need replace different crystallization properties having near outer surface in zones of different along profile depth.And, change on demand by the detected pressures difference and to the bed size, and randomly utilize the output of load sensor to discharge to guarantee particle speed on demand, just can carefully control the sedimentation rate of thermally decomposed carbon or other certain material.Because so careful control can be determined at the precise thickness that applies the arbitrary moment coating of operation.Like this, when specific workpiece is repeatedly applied, might carefully control by desired thickness, be accurate to 0.0254 millimeter (0.001 inch) coating layer thickness.Reach extremely important thereby commercial very valuable some parts of precision of allowable deviation for applying those, for example repair with heart valve, this is a valuable especially advantage of the present invention.
If it is too little that fluid bed becomes, the workpiece of coating will be floated suitably, and whole bed has the danger of collapse, and coating procedure is interrupted, and, may cause the result that coating workpieces must be abandoned from requirements for quality control.Adopt the present invention, this possible collapse of fluid bed can prevent certainly, because the trend that fluid bed becomes too little will be detected when beginning immediately, control module 82 can automatically take countermeasure to make bed return to required size rapidly.This measure normally slows down the speed that particle is removed from bed, the bed size is progressively increased up to required size rebulid.On the other hand, if bed too increases, not only the characteristic of thermal decomposed deposition carbon can become not good, and sedimentation rate is slack-off, consequently one give fixed sedimentation time after, coating layer thickness is than giving the thin of phase, the hardness of the thermally decomposed carbon coating of deposition is general also poor than what deposit in less fluid bed.Therefore, it is also important that and prevent that bed from becoming undue big.The present invention also can prevent the appearance of phenomenon here.For example rely on control module 86 to increase the speed that particle is removed from bed, too increase if measure the bed size.
Detect the pressure of bed top and just below bed or the pressure of bed lower area, though best adopts pressure sensor 78, other suitable device for pressure measurement also can use.The pressure of direct gaging pressure sensor 70 of for example available water column differential manometer and 72 positions poor, also available two liquid manometers or other accurate barometer formula instrument are measured the pressure of this two positions, the result who relatively measures then respectively.
Be shown in Fig. 2 be device 20 ' another kind of embodiment, it is characterized in that to be shown in the pressure measxurement upper channel of Fig. 1, and there is the exhaust uptake 100 of a weak point that inert gas and thermal decomposition gaseous product are led to a correct position, for example lead to the inlet of waste gas exhaust pipe 102, discharge continuously by it then and leave equipment place building or room.As seen from the figure, at the end of exhaust uptake 100 and the arrival end of blast pipe 102 a segment length 2.54-15.24 centimetre space is arranged.For that reason, and because the cross section broad of exhaust uptake, about 5.08 centimetres of internal diameter (2 inches) for example, the pressure of fluid bed upper zone is essentially atmospheric pressure in the applicator.So it is suitable finding to allow 78 of pressure sensors detect applicator 20 ' outer atmospheric pressure rather than the interior just pressure above bed of detection coating room, because in the case, the pressure at this place is actually atmospheric pressure.Thereby find, detect atmospheric pressure by conduit 74 ', then with the pressure ratio of the bed inferior segment that detects by conduit 76, and will represent the signal of the difference of these two pressure to be sent to control module by circuit 84 be to utilize these measured values control bed sizes also thereby accurately obtain another suitable method of required coating feature and thickness in the thermal decomposed deposition process.
An example of fluid bed coating unit operation that has embodied the various characteristics of the present invention is as follows.Elder generation's open valve 52 also goes to a correct position to provide from the inert gas of source of the gas 50 nitrogen for example, makes the fluidization nitrogen applicator 20 of flowing through up, and source of the gas can be the equipment of pressure bottle and so on.The particle of right quantity adds applicator to set up fluid bed from the upper end then.For example, for the coating room internal diameter be about 8.89 centimetres (
Inch) applicator, 250 to 500 its granularities of gram of can packing into earlier be greater than about 325 microns, but apply the zirconia particles of thermally decomposed carbon less than about 700 microns oneself.This particle in the initial bed has applied thermally decomposed carbon, different with the zirconia particles of the uncoated that in coating procedure, adds bed subsequently, the latter's density is about 5.37g/cc, about 300 microns to about 425 microns of its granularity (about 360 microns of particle mean size), this uncoated particle is contained in the particulate feeder 40.The typical ruuning situation of this size applicator is that about 20 to 40 orifice rings are added in the bed.This class ring will be as the lobe body of repairing with heart valve after applying.Typical orifice ring generally is the short tube shape, high about 0.7cm, and internal diameter about 1.5 is to 2.5cm, and external diameter about 1.6 is to 2.6cm.U.S. Patent No. 4,822,353 and No.4,863,467 have represented to adopt the heart valve of this general type lobe body.
Then equipment being warming up to about 1200 ℃ to 2000 ℃ operating temperatures, is that with induction heating apparatus 44 particle and workpiece evenly to be heated to temperature required.The typical about 1320C of operating temperature.Between temperature raising period, in conduit 56 (its import is 0.476 centimetre hole), keep the stream of nitrogen up of capacity and discharge to avoid particle.Equally below also keeping 4 liters of similar nitrogen qi of chong channel ascending adversely of sufficient about per minute in the pressure port and flowing to avoid particle to enter this pressure port.In the applicator of Fig. 1, to discharge conduit 56 and place conical surface 30 top edges about 1.016 centimetres (0.4 inches) that make its inlet hole 57 be lower than following lining to locate, this position is in the middle part of bed approximately; And this conduit can change orientation and make its hole 57 face the inboard substantially, for example with line by the coating room center line angle into about 45 °.This occupies the volume of about 278.63 cubic centimetres (17 cubic inches), about 12.7 centimetres of the vertical height that the conical surface of following lining has (5 inches) bed in coating room.In illustrated equipment, the bottom surface of the bed that mouthful 72 seat total depths are about 10.16 centimetres above about 6.35 centimetres (2.5 inches).Yet because bed has part butt taper shape, this hole is positioned among the bed volume Lower Half.
When applying the operation beginning, open valve 48 makes certain suitable coating gas (for example propane) add oneself the flow through fluidizing gas of pipeline 54 and central passage 32.In order to make the thermally decomposed carbon alloying that is depositing with carborundum, as this class skill, know, the most suitable is that methyl trichlorosilane is added air-flow.If need, the flow of regulating inert gas make fluidization-coating with admixture of gas the air-flow by application chamber up, surveying in standard temperature and pressure (STP), is about 13 liters/minute nitrogen, about 7 liters/minute methane and about 1 liter/minute methyl three nitrogen silane steams.In case apply the operation beginning, particulate feeder just begins uncoated zirconia particles is passed through in feeding-passage 42 input equipments with the speed of about per minute 2 grams, and these particles fall into fluid bed and become its part.Because density is bigger, uncoated granule promptly mat gravity is reduced to the bed inferior segment.Also keeping the nitrogen qi of chong channel ascending adversely stream of 4 liters of about per minutes in feeding-passage, it is to flow together with the zirconia particles that is just descending; Above passing to, keeping the nitrogen qi of chong channel ascending adversely stream of 1 liter of about per minute simultaneously in the pipeline 74 of pressure sensing mouth 70.
Pressure differential under mat pressure sensor in whole coating operating process (for example commercially available SensotecModel Z or SETRA Model C239) detects between square opening 72 and the last square opening 70.Represent the output signal of institute's measuring pressure difference to be sent to electronic control unit 86 by sensor.This signal is compared with for example per 15 seconds interval and the program of representing required bed size.Control module 86 just carries out suitable adjusting to the speed of discharging particle removal in the conduit, makes pressure differential according to becoming for applying the requirement that operating period gives setting earlier.Maintain 4 liters of for example about per minutes at first by the nitrogen stream of discharging conduit (about 0.635 centimetre of its internal diameter) up by collecting chamber 62, this flow can prevent the particle discharge of significant quantity in the early stage.In general, the particle that constitutes bed is big more, and for the bed that given weight particles is housed, its total surface area is more little.Therefore, be necessary to discharge these larger particles, and constantly add and replenish it with tiny uncoated particle from bed.If the total surface area of bed significantly reduces, then applying speed will increase, and can cause to produce to contain the coating that significantly is mingled with cigarette ash, and it is difficult to polish.Therefore it also is very important avoiding bed too little.Mat control module 86 begins to regulate up the N that flows out particle tap 57 (it is positioned on the sidewall of conduit of top seal) by conduit 56 then then
2Air-flow.The method of its adjusting for example is periodically to reduce flow in the very short time interval in second, to realize the rate of discharge of about 6 to the 8 gram particles of per minute.Feedback from load sensor can make control module carry out fine adjustment, for example changes the length in (low discharge) time interval or/and its frequency.
This typical coating operation was carried out about altogether 180 minutes.Its operating condition is to make the difference that keep-uped pressure earlier at initial 60 minutes equal about 10.16 centimeter water columns, in second stage pressure differential is progressively reduced to 7.62 centimetres of (3.0 inches) water columns with uniform rate in about 60 minutes then, then keeps this value later on always.The change dependence of pressure differential reduces the bed size and realizes, it will cause sedimentation rate to increase.After applying EO and apparatus cools, coating workpieces is checked, found that the thermally decomposed carbon of the SiC alloying above it is of high quality 2.54 * 10
-2The coating layer thickness of centimetre (0.010 inch) is very even, with the tolerance of required thickness about 2.54 * 10
-3Centimetre (0.001 inch).
The coating of above-mentioned condition operates in the applicator that the sort of upper end has short exhaust uptake and also repeats it, and this flue leads to the exhaust manifolds of top, and the gas in the equipment is by its speed discharging with per minute about 4.248 cubic metres (150 cubic feet).About 5.08 centimetres of flue internal diameter (2 inches), distance is about 7.62 centimetres between its outlet and the exhaust manifolds inlet.Operate for the coating in this equipment, the pressure sensor that does not use passage 70 to be provided, but measure near the outer atmospheric pressure of applicator, and this value and the bed inferior segment pressure of measuring by pipeline 76 and sensor 72 are as previously mentioned compared with pressure sensor.This information equally also is sent to control module by circuit 84.Carry out same coating operation then as previously mentioned.The carborundum one thermally decomposed carbon coating workpieces of finding gained on inspection has very high quality equally, has obtained uniform coating layer thickness equally, is accurate to 2.54 * 10 for required dimensions
-3Centimetre.Therefore, with detect coating room in just compare in the mode of the pressure of bed top, the mode that detects near the outer atmospheric pressure of applicator also can make operation satisfied, and also obtains far away from the thickness allowance with interior coating.
In general, the invention provides method and the instrument that very accurately to control the process of thermally decomposed carbon and so on electrodeposition substance to the base material that floats in grain fluidized bed.Promptly, can obtain weighing very accurately of bed size by the pressure (actual under many situations is exactly atmospheric pressure) of detection bed top and the mechanism of the difference of lower position (or just below bed) pressure of bed volume 25%.This measurement is Input Control Element then, the design of this control module is can carry out essential adjusting to make the in fact invariable bed size of keeping a preliminary election in coating room, if need, also can be in the whole change that applies operating period according to the programme-control bed size of predetermined establishment.Though the present invention is by some suitable conditional statement of implementing, and need know that for those of ordinary skills, can carry out various variation and correction within scope of the present invention, this scope is only by claims defined after being additional to.For example, though the deposition of the thermally decomposed carbon of thermally decomposed carbon or silicon carbide alloysization is only handled in the narration here, the carbide material of other alloying also can use (for example zirconium carbide or tungsten carbide), and other material also can deposit from vapor atmosphere (for example 100%SiC).
Characteristics of the present invention are stressed it in the following claims.
Claims (20)
1. in the method that flies at the process on the grain fluidized bed base material, this deposition process is carried out in a settling chamber that has gas upwards to flow, and it is characterized in that described method comprises with a certain electrodeposition substance in energy precision control:
Set up a grain bed that is in fluidized state in described chamber, have at least a base material to be coated to float in this fluid bed, showy is to be realized by gases used flowing up,
Particle and base material are heated to temperature required, the decomposable component of will being heated joins and makes this component generation thermal decomposition in the described gas, thereby required thermal decomposition material is deposited on base material and the particle, and this moment, base material and particle all were in afloat,
Controllably particle is discharged by bed,
Controllably particle is added bed, the particle mean size of feed particles is less than the particle mean size of discharging particle,
In the inside of bed or preposition below it and detected pressures respectively above bed, thereby draw the difference of the two pressure,
Pressure differential change particle corresponding to gained adds the speed of particle or changes this two speed simultaneously by the speed of bed discharge or to bed, make and accurately to regulate deposition, thereby on described coated base material, produce accurate coating in long-time scope.
2. the method for claim 1 is characterized in that described gas contains the hydrocarbon that can decompose deposit carbon.
3. method as claimed in claim 2 is characterized in that described gas had both contained main certain inert gas of amount and also contained a spot of certain organo-silicon compound, and this compound deposits carborundum with the thermally decomposed carbon alloying in temperature required decomposition.
4. as each described method among the claim 1-3, it is characterized in that certain the upright position gaging pressure in the bottom half of described bed cumulative volume.
5. as each described method among the claim 1-3, it is characterized in that carrying out pressure measxurement in the zone of fluid bed bottom 25% volume, this zone of doing this measurement generally is the butt taper.
6. as each the described method among the claim 1-3, it is characterized in that with particle base material is applied whole during in add bed continuously with an in fact constant speed.
7. method as claimed in claim 6 is characterized in that changing the speed of discharging particle from described bed corresponding to this pressure differential of measuring.
8. method as claimed in claim 7 is characterized in that mat changes inert gas flow and controls the speed of being discharged particle by fluid bed, and this inert gas flow is opposite with the discharge direction of particle mat gravity flow, is upwards to flow.
9. method as claimed in claim 7 has in the particle that adds in its feature and is equal to or less than 400 microns particle mean size, and the particle of discharging from fluid bed in the whole process that base material applies has the particle mean size greater than 500 microns.
10. as each described method of claim 1-3, it is characterized in that the density of the density of coating substance less than the particle of heavy this bed of structure.
11. method as claimed in claim 10 is characterized in that the particle that is added into is the compact zirconia of its density greater than coating substance.
12. method as claimed in claim 11 is characterized in that in fact the particle layers of initial stage foundation constitutes by the zirconia particles that applies with thermally decomposed carbon.
13. as each described method of claim 1-3, it is characterized in that it being the position measurement pressure that the pressure sensing mouth that constant inert gas flow flows through is arranged in over a long time, above bed and at the terminal position gaging pressure of the passage that extends to coating room.
14. an energy precision is controlled at together with the method for carrying out the thermally decomposed carbon deposition process on the grain fluidized bed base material that floats, and it is characterized in that this method comprises:
Set up the grain bed under the fluidisation attitude be equipped with at least one base material to be coated at coating area, particle and base material all float in the air-flow that makes progress,
Described particle and base material are heated to required heat decomposition temperature, in air-flow, insert heat decomposable carbonaceous component and make it that thermal decomposition take place, thermally decomposed carbon is deposited on base material and the particle,
The precalculated position of inner or its below of inherent over a long time bed and above bed detected pressures, thereby determine its pressure differential,
Corresponding to the grain amount in this pressure differential adjusting bed of measuring, so that the deposition process of in long-time, accurately regulating thermal decomposition, thereby accurate coating on described base material, produced.
15. on the base material that flies in grain fluidized bed, carry out the equipment of electrodeposition substance, it is characterized in that this equipment comprises
A coating room,
At the device of a mixed gas flow up of this indoor generation, its effect is to keep to make grain bed be in fluidised condition and make at least one base material to be coated that floating in fluid bed in coating room,
Make base material and the grain fluidized bed heater of keeping uniform temperature, this temperature will make mist that thermal decomposition takes place in fluid bed enough, make required thermal decomposition material be deposited on base material and particle above,
By the device of fluid bed discharge particle,
With the device of particle mean size less than the particle adding fluid bed of discharging average particle size,
Or a precalculated position it below inner at fluid bed and above fluid bed respectively detected pressures making the device of its pressure differential,
Can in over a long time, add the speed of particle or change this two speed simultaneously from the speed of fluid bed discharge particle or to bed, thereby accurately be adjusted in the device of the deposition process on the coated substrate corresponding to this pressure differential change of being made.
16. device as claimed in claim 15, the device that it is characterized in that changing speed are energy the particle discharger is regulated to change the electronic control unit of particle rate of discharge.
17. device as claimed in claim 16 is characterized in that the device of detected pressures comprises a pressure sensor, it produces signal and is sent to electronic control unit.
18. device as claimed in claim 15 is characterized in that the checkout gear of described pressure comprises the pipe guide that extends to certain position in the fluid bed and keeps the device of inert gas qi of chong channel ascending adversely stream by this conduit.
19. as each the described device among the claim 15-18, it is characterized in that described coating room is substantially cross section, garden shape, its diameter is equal to or less than 15.24 centimetres.
20., it is characterized in that the speed supply particle of particle feeding device with a substantial constant as each the described device among the claim 15-18.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92105230A CN1044336C (en) | 1991-11-18 | 1992-06-30 | Pyrolytic deposition in a fluidized bed |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/793,588 US5284676A (en) | 1990-08-17 | 1991-11-18 | Pyrolytic deposition in a fluidized bed |
| CN92105230A CN1044336C (en) | 1991-11-18 | 1992-06-30 | Pyrolytic deposition in a fluidized bed |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1080667A CN1080667A (en) | 1994-01-12 |
| CN1044336C true CN1044336C (en) | 1999-07-28 |
Family
ID=25742763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN92105230A Expired - Fee Related CN1044336C (en) | 1991-11-18 | 1992-06-30 | Pyrolytic deposition in a fluidized bed |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1044336C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020198703A1 (en) * | 2019-03-28 | 2020-10-01 | Rec Silicon Inc | Pressure-based control of fluidized bed reactor |
| CN113840703B (en) * | 2019-05-17 | 2023-11-28 | 康宁股份有限公司 | Inline extrudate bow measurement and control |
| CN110331403B (en) * | 2019-07-10 | 2020-07-17 | 中国科学院过程工程研究所 | System and method for preparing ZrC and ZrN coating layers in fluidization mode |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3977896A (en) * | 1972-03-09 | 1976-08-31 | General Atomic Company | Process for depositing pyrolytic carbon coatings |
| US4546012A (en) * | 1984-04-26 | 1985-10-08 | Carbomedics, Inc. | Level control for a fluidized bed |
| US4594370A (en) * | 1985-03-29 | 1986-06-10 | The Mead Corporation | Amine-formaldehyde microencapsulation process |
| US4859493A (en) * | 1987-03-31 | 1989-08-22 | Lemelson Jerome H | Methods of forming synthetic diamond coatings on particles using microwaves |
-
1992
- 1992-06-30 CN CN92105230A patent/CN1044336C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3977896A (en) * | 1972-03-09 | 1976-08-31 | General Atomic Company | Process for depositing pyrolytic carbon coatings |
| US4546012A (en) * | 1984-04-26 | 1985-10-08 | Carbomedics, Inc. | Level control for a fluidized bed |
| US4594370A (en) * | 1985-03-29 | 1986-06-10 | The Mead Corporation | Amine-formaldehyde microencapsulation process |
| US4859493A (en) * | 1987-03-31 | 1989-08-22 | Lemelson Jerome H | Methods of forming synthetic diamond coatings on particles using microwaves |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1080667A (en) | 1994-01-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5284676A (en) | Pyrolytic deposition in a fluidized bed | |
| CA1307774C (en) | Closed loop powder flow regulator | |
| US4546012A (en) | Level control for a fluidized bed | |
| US5514410A (en) | Pyrocarbon and process for depositing pyrocarbon coatings | |
| US7955031B2 (en) | Material supply system and method | |
| US6046426A (en) | Method and system for producing complex-shape objects | |
| US3977896A (en) | Process for depositing pyrolytic carbon coatings | |
| CN1044336C (en) | Pyrolytic deposition in a fluidized bed | |
| US5328720A (en) | Coating-fluidizing gas supply system and method for flat bottom coater | |
| JPS5925756B2 (en) | Method for coating graphite or ceramic objects | |
| AU662748B2 (en) | Pyrolytic deposition in a fluidized bed | |
| CN1482083A (en) | Raw material providing device for chemical vapor deposition process | |
| US4459071A (en) | Solids flow regulator | |
| Fletcher et al. | Fluidization of a multi-sized Group B sand at reduced pressure | |
| US5328713A (en) | Precise regulation of fluidized bed weight in pyrolytically coating substrates | |
| KR100204110B1 (en) | Pyrolytic deposition in a fluidized bed | |
| US2867478A (en) | Pulsating counter-flow feeder | |
| EP0749354A1 (en) | Regulation of pyrocarbon coating | |
| CN102066606B (en) | Machine for processing vessels made of thermoplastic material | |
| GB2055733A (en) | Method of producing a uniform stream of particles conveyed in a conveying duct by means of a conveying medium and apparatus for carrying out the method | |
| JPS61187634A (en) | Method and apparatus for limiting particle flow channel | |
| JPH0526732B2 (en) | ||
| JPS6022275B2 (en) | Pressure adjustment device for the discharge opening of fired products in a continuous air firing furnace | |
| JPH0660725B2 (en) | Control method of combustion air amount in fluidized-bed furnace | |
| KR20060089304A (en) | Optical preform fabrication equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
| OR01 | Other related matters | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |