CN100414278C - Capacitance manometer having a relatively thick flush diaphragm under tension to provide low hysteresis - Google Patents
Capacitance manometer having a relatively thick flush diaphragm under tension to provide low hysteresis Download PDFInfo
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- CN100414278C CN100414278C CNB2004800137583A CN200480013758A CN100414278C CN 100414278 C CN100414278 C CN 100414278C CN B2004800137583 A CNB2004800137583 A CN B2004800137583A CN 200480013758 A CN200480013758 A CN 200480013758A CN 100414278 C CN100414278 C CN 100414278C
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Abstract
The invention relates to a capacitance diaphragm meter (100) used for measuring the pressure, which comprises a gasket (122) or flat diaphragm (120) of which other protruding peripheral parts are arranged on a main body structure.
Description
Background of invention
Invention field
The invention belongs to art of pressure sensors, this pressure transducer has variable electric capacity being exposed between barrier film under the pressure and the fixed electorde.
Description of Related Art
(capacitance diaphragm gauge CDG) comes gaging pressure to have made electricity capacity barrier film meter for many years.CDG (for example much lower than atmospheric pressure pressure) when measuring low-down pressure is useful especially, such as the pressure of measuring in the evacuation system (for example semi-conductor manufacturing system).CDG can produce a kind of electricity output, and the measured value with respect to the pressure input of reference pressure has been represented in this electricity output.
Basically, a kind of exemplary CDG comprises that at least one is supported on the electrode on the suitable support structure.This electrode is close to a flexible partition in a sealing and the chamber of finding time.This barrier film is arranged so that in this equipment the one side (pressure-bearing surface) of this barrier film is exposed under the unknown pressure that will measure.This electrode is close to the opposing face (electrode surface) of this barrier film.Measure this unknown pressure on the pressure-bearing surface with respect to the reference pressure on the electrode surface.This reference pressure is constant in the sealing and the chamber of finding time basically.This barrier film and electrode have constituted two pole plates of a variable condenser, and the electric capacity of this capacitor is in response to changing the diaphragm flexes that causes by pressure and changing.
In many application, this CDG is located in the suitable housing of pressure measuring device, and the pressure-bearing surface of this barrier film is exposed to via suitable passage under this unknown pressure.Or the pressure-bearing surface of this barrier film can directly be exposed under this unknown pressure.For example, this CDG can be mounted to and make the pressure-bearing surface of this barrier film be arranged in airflow line, and in this case, the barrier film of CDG and other parts preferably can not extend to comes part to stop this air-flow or cause turbulent flow in this air-flow in this air-flow.If any part of this CDG does not extend beyond the pressure-bearing surface of this barrier film, this pressure-bearing surface can be mounted to the inwall of airflow line and flush basically so.A kind of CDG with this structure is called as flat membrane (flush diaphragm) design.Those skilled in the art will appreciate that flat membrane CDG can be soldered in the housing and makes a kind of more general equipment.On the other hand, the CDG that does not have flat membrane can not be transformed into usually and be used in the application that needs flat membrane equipment, and this is because the supporting construction of this barrier film has extended beyond the pressure-bearing surface of barrier film.
Be known in the art CDG with flat membrane.For example, the flat membrane CDG of the first kind is that the solid block with suitable material processes, and stays skim and forms this barrier film at an end of this piece.In some cases, can heat-treat this material for certain Expected Results or owing to material properties.
The flat membrane CDG of another kind of known type is called as ripple barrier film CDG.This ripple barrier film has and is formed on the ripple in the surface and causes occurring extra material, so that response institute's applied pressure and produce more linear bending.The barrier film that is used for the type is normally soldered on the throne.
The flat membrane CDG of the 3rd type has the barrier film that forms with thin material.This thin material is in some way by high elongation and soldered on the throne.
Ben is the hysteresis characteristic of finished product pressure measuring device.Hysteresis is meant when becoming into a setting pressure from different directions the difference between (that is: when unknown pressure descends from higher pressure into this setting pressure that becomes, relative is, into this setting pressure becomes from lower pressure) sensor output when unknown pressure rises.Although this setting pressure should produce identical output valve, and with previous pressure independent, but when this setting pressure is to become when into coming from high pressure more, lag-effect can make that this output valve is too high, and when this setting pressure be to become when into coming from low-pressure more, lag-effect can make this output valve low excessively.
The maximal value of this hysteresis error normally is in the midrange place of pressure skew.Skew from zero pressure to full scale pressure is maximum normal skew.Unusual skew can cause bigger error.Because hysteresis error depends on the amplitude of pressure skew at least in part, so this hysteresis error is normally uncertain and thereby be subject matter.On the contrary, such as other error of linear error or temperature error because of its be reproducible and thereby be predictable, so their easier being corrected.
Bear the barrier film of pressure and will bear pressure load.Be applied to the bending that difference between the pressure on the barrier film opposite sides causes barrier film.The electrode surface of barrier film is as a pole plate of variable condenser, and this capacitor is with electrode another pole plate as capacitor.If also comprise other electrode, so just form a plurality of capacitors, and the electrode surface of barrier film forms a pole plate of each capacitor.The bending of this barrier film is moved into this barrier film more close or is located farther from electrode, thereby has changed electric capacity.Measure this electric capacity with suitable traditional approach, so that provide one can measure in response to the pressure that is applied to the barrier film pressure-bearing surface.
In order to produce the reproducible measurement to unknown pressure, the diaphragm flexes that is taken place should have as far as possible little hysteresis.That is to say that when pressure returns to before when big or small, this barrier film should return to its previous case of bending, and no matter this pressure is to rise earlier to descend or descend earlier to rise again.
Reducing of lagging behind realized by bearing load under extended state.Have been found that variation in response to pressure, the change of stretch range is more little then lag behind more little, thereby and cause bigger measuring accuracy.A problem of high-tension measurement equipment is to keep enough little bending by the prestretched with bearing load.
Used a lot of technology to come the prestretched barrier film, particularly for the barrier film among the low pressure CDG; Yet the technology that is used for autoclave diaphragm is very limited, and when equipment became more miniaturization, these technology were just more limited.A kind of technology that has been used for the prestretched barrier film is to heat barrier film before the main body that barrier film is welded to CDG earlier, makes this barrier film shrink and form when cooling and stretches.Coming the trial of prestretched barrier film to comprise with this technology in the past contacts barrier film with heating platen.This technology makes whole anchor clamps heating, thereby causes great uncertainty when handling follow-up unit in the result.A kind of like this technology between barrier film and heating platen, keep good thermo-contact aspect also can go wrong, this also makes the final stretching on this barrier film to reappear.
The supporting construction of typical case among the CDG forms single, and a part that is adjacent to barrier film in this structure provides the function of pad, makes barrier film open at its rest position or null position and electrode gap.This pad is formed the part of CDG main body, and this is a kind of take in order to obtain the interval between barrier film and the electrode very expensive and the mode that can not reappear.For example, the thin lip limit of this pad needs processing very carefully, so that the tolerance that needs in order to produce reproducible initial zero electric capacity is provided.When diaphragm flexes, this pad is under the very big pressure.Therefore, this pad need be stone.In order in single design, to obtain required hardness, this part after processing by thermal treatment.This thermal treatment can be so that the needed spacing accuracy of accurate measurement is twisted and lost to this part.
Summary of the invention
Provide a kind of electric capacity barrier film meter (CDG) that has flat membrane according to embodiments of the invention, this flat membrane has low hysteresis characteristic.This CDG has the simple structure that can make in the mode that can bear economically with reappearing.
An aspect according to embodiments of the invention is a kind of electric capacity barrier film meter (CDG) that has flat membrane, this flat membrane is installed on the main body of CDG by such technology, promptly produce the very prestretched of height on this barrier film, the intensity size of its prestretched is about half of ultimate strength size of this diaphragm material.Such prestretched has been brought to best operating point, and this best operating point makes the bending stress of this barrier film minimize with respect to allowable stress.Because the bending stress on this barrier film is the main cause that lags behind, make to lag behind by this technology so to minimize.
Particularly, among the described embodiment, before being welded to the CDG main body, barrier film to apply heat here to barrier film.After welding is finished, owing to barrier film shrinks in cooling, thereby with this barrier film prestretched.
In a preferred embodiment, shine this barrier film with high-level radiation.For example, can provide this radiation with laser or other appropriate sources.In a special embodiment, produce this radiation with Halogen lamp LED, this Halogen lamp LED is suitably arranged so that shine the one side of this barrier film.Start this radiation source several seconds before welding process begins, and maintenance work in welding process.Improve the absorption of radiation by improving this barrier film with respect to the radiance around it, make this radiation heat this barrier film selectively.By improving the temperature of barrier film with respect to CDG main body material around, this barrier film expanded with respect to material around before welding process.In membrane becomes expanded, barrier film is welded, so that this barrier film becomes when cooling off after welding is finished by prestretched.
The radiation intensity that comes from laser, Halogen lamp LED or other radiation source can fully be controlled so that reproducible temperature is provided, and makes this prestretched produce to be about half reappeared stress of ultimate stress.
Thereby common metal has low-down radiance and has low-down absorptivity.Basically all incident radiations all have been reflected, and the remaining temperature that small amount of radiation improved is not enough.And the raising of this temperature can not produce reproducible result.According to this particularly preferred embodiment, by improve the radiance of membrane surface with carbon or other suitable material coating surface.Preferably, apply the surface of this barrier film by this way, promptly allow after welding process is finished, can easily clean this barrier film.For example, have been found that carbon black (for example coal smoke) is suitable for improving radiance and is removed easily after this process is finished.In a special embodiment, be exposed to by pressure-bearing surface under the oxidizing flame (for example coming from lighter etc.) of butane and apply carbon black barrier film.This oxidizing flame deposits the carbon of skim on pressure-bearing surface.This thin carbon layer absorbed radiation, so as other parts keep cold relatively in the barrier film Fast Heating.The easy flush away of this carbon-coating and need not abrasive cleaning.
The CDG of the unmachined barrier film that technology as described herein is used to produce and has independently, approaches.Than following very expensive process: " process single barrier film and support member, then after processing the thermal treatment barrier film and do not make this diaphragm deflection ", this barrier film is to be obtained optimum performance by thermal treatment easily.Process as described herein allows with a kind of cost efficient and best mode barrier film to be installed on the support member, and the remarkable performance about the diaphragm flexes characteristic is provided.Particularly, this barrier film has low hysteresis.
Existing equipment has single agent structure, and this agent structure has the pad that forms an agent structure part, and is different with this existing equipment, and embodiments of the invention comprise the separate insert that can heat-treat separately.As this barrier film, this pad does not need to be machined yet.Therefore, this pad in no case can be out of shape or change its thickness.Like this, obtained to have the optimum performance that can reappear characteristic with the low-cost parts of making easily.As a result, be a kind of simple, the parts that can be mass-produced according to the supporting construction (for example main body of this CDG) of embodiment as described herein.
For welding barrier film in heating, when will be heated barrier film and pad are welded to the CDG main body, with this barrier film and spacers between the seaming chuck and lower support surface of fluid power mandrel press.In the structure of non-flat membrane, also in same process, weld support ring outside, and keep parts as CDG.In order to obtain the flat membrane according to embodiment as described herein, in welding process, this barrier film is placed on the reusable support fixture.This support fixture is located on the lower support surface of mandrel press, and forces the rear surface of seaming chuck against the CDG main body.In welding process, the pressure of mandrel press has been fixed to barrier film on the CDG main body.This support fixture comprises high temperature (for example infusibility) material, thereby this material can not melt in welding process and can be attached on the barrier film.Exemplary refractory material such as tantalum and silit all is suitable for support fixture.
Different with the single part formula electrode design in past, comprise one or two component type electrode according to optional embodiment of the present invention, two component type electrodes provide stable electric capacity under variation of temperature.Electrode response has improved the rest capacitance amount in the expansion of temperature.The raising of rest capacitance amount can be offset by the interval that increases between barrier film and the electrode.The interval that is increased can be by making the clean expansion of single electrode provide less than the support passage of passing pad.This is to use two component type electrodes to realize in a preferred embodiment.The two component type electrodes that are applicable to high-tension measurement comprise the outer part that contains titanium or titanium alloy.This titanium or titanium alloy material have stand high pressure CDG the high strength engagement characteristics of unique excess pressure.The interior part of this two component types electrode is connected to outer part by welding (or other connects the suitable mode of these two parts as welding).For example, the stainless steel of having found 300 series be suitable for as should in part.Among the described here embodiment, part preferably comprises nickel in this.Selectively, also can realize suitable performance with the single part formula electrode that contains titanium or titanium alloy.
Comprise second electrode that the periphery of contiguous barrier film is provided with according to other embodiments of the invention,, can handle this signal and offset this bulking effect so that come expansion between compensating electrode and the barrier film by providing second electric capacity to measure signal.
Brief description of drawings
Below in conjunction with accompanying drawing the aforementioned feature and the further feature of the embodiment of the invention are described, wherein:
Figure 1A is the front perspective view of an embodiment of electric capacity barrier film meter of the present invention (CDG), has wherein demonstrated the pressure-bearing surface of flat membrane;
Figure 1B is the rear view of the CDG of Figure 1A, wherein demonstrates the guarded electrode joint, has been used to form the threaded hole that is electrically connected with the main body of CDG, and by the evacuation tube of pinch off;
Fig. 2 A is the xsect along the CDG of Figure 1A of the line 2A-2A extraction of Figure 1A;
Fig. 2 B is the amplification xsect along the CDG of the line 2B-2B extraction of Fig. 2 A, so that show the pad between barrier film and the CDG main body in greater detail;
Fig. 3 is the back perspective exploded view of the CDG among Figure 1A and Figure 1B, has wherein shown electrode, electrode shield, insulating glass blank and evacuation tube;
Fig. 4 is the preceding exploded view of the CDG among Figure 1A and Figure 1B, has wherein shown the relation between barrier film, pad and the electrode;
Fig. 5 is the part cross sectional representation of CDG main body, pad and barrier film, they are arranged on the reusable support ring in the fluid power mandrel press, in welding process, when applying radiation to heat barrier film, radiation source exerts pressure by this fluid power mandrel press;
Fig. 6 is the xsect of the another kind of embodiment of the present invention, wherein provides two electrodes to compensate interval between barrier film and the central electrode with variation of temperature.
Detailed description of preferred embodiments
Figure 1A, 1B, 2A, 2B, 3 and 4 show the electric capacity barrier film meter (CDG) 100 of a kind of embodiment.Shown in Figure 1A, this CDG 100 comprises agent structure 110, and this agent structure 110 has the agent structure 110 of front surface 112 (see figure 4)s and rear surface 114 (see figure 4)s.Among the embodiment that goes out shown here, agent structure 110 is cylindrical generally, and front surface 112 and rear surface 114 are circular.In the preferred embodiment, the area of front surface 112 is less than the area of rear surface 114, and the diameter of the back column part 118 of the neighbour nearly rear surface 114 of diameter of the preceding column part 116 of contiguous front surface 112 is little in the agent structure 110, so that agent structure 110 have from forward part 116 to the rear section 118 step-shaped transition, this step-shaped transition forms the lip limit 119 around forward part 116.In some applications, can when being installed, use this CDG 100 this lip limit 119.
The front surface 112 of contiguous agent structure 110 is installed flat membrane 120, and with circular gasket 122 with this flat membrane 120 and this front surface 112 spaced apart (in Fig. 2 A, 2B and 4, showing clearlyer).This barrier film 120 has the diameter of about 1 inch (2.54cm) and scope at 0.001 inch (0.025mm) thickness to 0.015 inch (0.38mm).Preferably, this barrier film 120 comprises inconel (Inconel) 750 or other suitable material.
This circular gasket 122 comprises the Inconel 750 that forms thin ring, and this thin ring has the overall diameter of about 1 inch (2.54cm) and the interior diameter of about 0.98 inch (2.49cm).In a kind of preferred embodiment, this pad 122 has the thickness of about 0.003 inch (0.08mm).Like this, this barrier film 120 and this front surface are 112 spaced apart about 0.003 inch.In the preferred embodiment, this pad 122 is separate units as shown in the figure.This pad 122 forms the raised perimeter portion on the border of the flat front surface 112 that defines agent structure 110.In optional embodiment, utilize Machining Technology or other proper technology, this pad 122 can form the part of agent structure 110, so that flat basically core forms a raised perimeter portion in the front surface 112.This raised perimeter portion has the net thickness of measuring perpendicular to the core of front surface 112, the consistency of thickness of this net thickness and pad 122, and this is such just as previously discussed.
As clearlying show that in Fig. 2 A and 4, cylinder hole 124 extends through main body 110 from front surface 112 and arrives rear surface 114, and this cylinder hole 124 is placed in the middle with respect to these two surfaces basically.Electrode assemblie 130 extends through this cylinder hole 124.This electrode assemblie 130 comprises the cylinder electrode 132 that surrounds with coaxal electrode radome 134.This electrode assemblie 130 is arranged to pass this cylinder hole 124, makes the front surface 138 of the front surface 136 of this electrode 132 and this electrode shield 134 flush in the front surface 112 of agent structure 110 basically, shown in Fig. 2 A and 4.
Shown in Fig. 2 A, use the first concentric insulator 140 that is arranged between electrode 132 and the electrode shield 134 with this electrode 132 and these electrode shield 134 electrical isolations.Similarly, the second concentric insulator 142 is located between the wall of electrode shield 134 and cylinder hole 124.With the wall electrical isolation of this second concentric insulator 142, thereby just insulated with agent structure 110 with electrode shield 134 and hole 124.
As shown in Figure 3, this first concentric insulator 140 preferably forms in the following way, promptly place more than first ring glass blank 140a, 140b, and this electrode shield 134 is arranged on this more than first glass blank 140a, 140b round a part of electrode 132.The second concentric insulator 142 preferably forms in the following way, promptly places more than second glass blank 142a, 142b, 142c, 142d round electrode shield 134, then electrode shield 134 is arranged in the cylinder hole 124.The size of this glass blank 140a, 140b can be with electrode 132 centering basically in electrode shield 134, and the size of glass blank 142a, 142b, 142c, 142d usually can be with electrode shield 134 centering in cylinder hole 124.
In the alignment jig (not shown), these parts are carried out described layout.The front surface 136 of this electrode 132 preferably includes aperture 144, and this aperture 144 can engage with the pin (not shown) in the alignment jig.Similarly, the contact plug 146 that can extend out with the rear surface 148 from electrode 132 of the hole (not shown) in this alignment jig engages.This hole 144 and pin 146 remain on position substantially concentric in the electrode shield 134 with electrode 132, and being heated to up to glass blank 140a, 140b, 142a, 142b, 142c, 142d is enough to flow and then be cooled round electrode 132 and electrode shield 134.In some preferred embodiment, this glass blank 140a, 140b, 142a, 142b, 142c, 142d preferably comprise borosilicate glass, and borosilicate glass just is enough to soften to flow and form nonvolatil insulation round these parts under about 700 ℃ and engages.
After agent structure 110 is cooled, by grind or other proper method with front surface 112 equatings of agent structure 110, make the front surface 136 of electrode 132 flush with this front surface 112.
In the preferred embodiment, electrode 132 comprises forward part 132a and rear section 132b.This rear section 132b preferably comprises titanium, titanium have in response to temperature low-expansion coefficient.Therefore, raise and make glass preform flows and then reduce temperature and when forming permanent engagement, it is sufficient constant that the diameter of rear section 132b has kept, so that the glass bond that forms round rear section 132b has kept complete when glass hardens when temperature.
In the preferred embodiment, barrier film 120, pad 122 and agent structure 110 comprise Inconel750 or other suitable material.The forward part 132a of electrode 132 preferably comprises nickel.Expansion coefficient and agent structure 110, barrier film 120 and pad 122 in response to temperature that this forward part 132a is had are similar.Like this, the expansion of this forward part 132a is proportional with other parts basically with contraction, thereby has kept relatively more fixing interval with respect to barrier film 120.Electrode shield 134 preferably also comprises nickel, so that have similar expansion coefficient.
Fig. 5 shows a kind of being used for barrier film 120 and pad 122 is installed to system on the main component 110.As described above electrode 132 and electrode shield 134 are engaged with each other and join to after the agent structure 110, pad 122 and barrier film 120 mode with prestretched barrier film 120 is welded on the front surface 112 of agent structure.Particularly, pad 122 is located on the front surface 112, makes that the neighboring of pad 122 is consistent with the neighboring of this front surface 112 basically.Then circular diaphragm 120 is arranged on the pad 122.Then a kind of reusable ring tool anchor clamps (support fixture) 170 are arranged on barrier film 120 tops.
This agent structure 110, pad 122, barrier film 120 and tool holder 170 are arranged in the fluid power mandrel press 172, and Fig. 5 shows the part of this press with the part xsect.This tool holder 170 is placed on the cylindrical shape lower support surface 174 of mandrel press 170, and barrier film 120, pad 122 and agent structure 110 are placed on the tool holder 170.The cylindrical shape seaming chuck 176 of this mandrel press 172 is arranged on the rear surface 114 of agent structure 110.Apply the power of variation by hydraulic cylinder (not shown) or other legacy equipment to the pressure head 176 of mandrel press 172, thereby barrier film 120 and pad 122 are pushed this between the periphery and tool holder 170 of front surface 112.
Further as shown in Figure 5, radiant energy source 180 is arranged on barrier film 120 belows.For example, in shown embodiment, preferably provide this emittance with Halogen lamp LED 180.This emittance is directed to barrier film 120 and heats this barrier film and make this membrane becomes expanded.
Because this barrier film 120 comprises Inconel, it has the reflectivity that is generally high, and therefore the most of emittance that incides on the barrier film 120 from lamp 180 has been reflected usually.For the absorption of enhanced rad energy, this barrier film scribbles has the high radiant rate material, and this is because the also easy absorbed radiation energy of high radiant rate material.On the other hand, many high radiant rate coatings are difficult to remove from the surface.Remain in any on the exposed surface of barrier film 120 and stain the performance that material all may have influence on barrier film.In a preferred embodiment, the exposed surface of barrier film 120 scribbles dim (for example coal smoke) 182.For example, in one embodiment, on barrier film 120, form dim 182 by being close to this exposed surface to place the butane flame (not shown).As described below pad 122 and barrier film 120 are permanently attached to after the agent structure 110, are easy to water or gentle clean solution is removed from barrier film dim 182, and do not need to use abrasive material or the dynamics that to damage barrier film 120.
At the beginning, on the rear surface 114 of agent structure 110, apply the relative position that enough pressure keeps agent structure 110, pad 122 and barrier film 120, heat this barrier film 120 by emittance simultaneously, thereby make barrier film 120 expand by dim 182 absorptions.Then to these these built-up member apply total pressure so that this barrier film 120 is limited in the configuration that has expanded.
Starting soldering tip 190 is fused to barrier film 120 and pad 122 on the front surface 112 of agent structure 110.This soldering tip 190 (for example arc welding, laser bonding, electron beam welding or other suitable engaging process) in a conventional manner rotates around the periphery of barrier film, so that form continuous welding around the whole periphery of barrier film 120.Barrier film 120 and pad 122 are fixed on the agent structure 110, thereby form an annular seal space between the front surface 112 of the inside surface of barrier film and agent structure.
This tool holder 170 comprises refractory metal or other suitable material (for example tantalum or silit), and the fusing point of Inconel 750 materials that these materials are more used than agent structure 110, pad 122 and barrier film 120 exceeds a lot.Therefore, this tool holder 170 can not influenced by this welding process and can not be fused with other parts.These soldered parts take off from this tool holder 170 easily, and same tool holder 170 can repeatedly use.
When turning off lamp 180, barrier film 120 cools off gradually and shrinks.Yet because the neighboring of this barrier film 120 firmly is fixed on the agent structure 110, and agent structure 110 is not heated to any significant degree by emittance, therefore, the surface of this barrier film 120 stretch effectively and also when it cools off by prestretched.
Because the prestretched of being introduced by aforementioned assembly method, so barrier film 120 has very little hysteresis.When using in pressure sensing is used, the prestretched of barrier film 120 makes this barrier film return to its beginning and end bending position just after by pressure variation causing bending.
Further illustrate as Figure 1B and 3, a littler through hole 150 extends to rear surface 114 from front surface 112.In the assembling process of CDG100, evacuation tube 152 is installed in this hole 150.After CDG100 is fully assembled, apply low-down pressure, so that the interior any residual gas of cavity that will be formed between front surface 112 and the barrier film 120 is extracted out to evacuation tube 152.Then, clamp this evacuation tube 152 with the formation cold welding, and the excess electron excess fraction of evacuation tube 152 is removed and the protrusion of formation as shown in Figure 1B.
Notice that the xsect shown in Fig. 2 A does not illustrate through hole 150, evacuation tube 152 and threaded hole 160.
In certain embodiments, can also comprise that other through hole (not shown) is to allow to install air-breathing jar of traditional (not shown), so that remove the remaining afterwards any residual gas of pumping process with chemical method.
The method of the structure of this CDG100 and prestretched barrier film 120 allows to produce the CDG with bigger pressure sensing limit of power.For example, can make diameter and be about the barrier film 120 that 1 inch (2.54cm) and thickness is about 0.001 inch (0.025mm) and measure the pressure that holds in the palm in the 1 holder scope from 0.0001, and can be up to from 0.001 pressure that holds in the palm in the 10 holder scopes.Can make and have the barrier film 120 that similar thickness and diameter be about 2 inches (5.08cm) and measure the pressure that holds in the palm in the 0.1 holder scope from 0.00001, and can be up to from 0.001 pressure that holds in the palm in the 10 holder scopes.
The method of the structure of this CDG100 and prestretched barrier film 120 is particularly conducive to uses the more barrier film thicker pro rata with respect to the diameter of barrier film to make CDG, to measure the pressure of higher scope.
Up to now, the flat membrane that does not have available CDG to have prestretched under rational cost is measured higher pressure limit to realize low-down hysteresis and to have enough thickness.The structure of embodiment as described herein and method provide cheaply, point-device flat membrane, and this barrier film can be manufactured into and be used for various application.For example, can produce diameter with about 0.75 inch (1.9cm) and the barrier film 120 of 0.001 inch (0.025mm) thickness and measure the pressure that holds in the palm in the 100 holder scopes from 0.01.Can produce diameter with about 0.75 inch (1.9cm) and the barrier film 120 of 0.003 inch (0.076mm) thickness and measure the pressure that holds in the palm in the 1000 holder scopes from 0.1.Can produce diameter with about 0.75 inch (1.9cm) and the barrier film 120 of 0.01 inch (0.254mm) thickness and measure the pressure that holds in the palm in the 10000 holder scopes from 1.
Fig. 6 shows the xsect according to the CDG 200 of the another kind of embodiment of the present invention, wherein provides two electrodes to compensate the temperature variant variation in interval between barrier film and the central electrode.The embodiment of Fig. 6 is particularly conducive to the performance that improves the CDG with larger diameter barrier film (for example diameter of 2 inches magnitudes).The similar of CDG 200 is in the structure of aforesaid CDG 100, and do not have hereinafter the special like of discussing in Fig. 6 not by label.
This CDG 200 comprises the agent structure 210 that contains Inconel 750.This agent structure 210 is as general as circle, and the agent structure 110 of this and above illustrated CDG200 is the same.This agent structure 210 has the diameter of about 2 inches (5.08cm).This agent structure 210 has front surface 212 and rear surface 214.
The first hole 224a extends through the center that agent structure 210 arrives rear surface 214 from the center of front surface 212.The second hole 224b is parallel to the first hole 224a and passes this agent structure 210.The position of this second hole 224b is close to the periphery of front surface 212.
The first electrode assemblie 230a is located in the first hole 224a, and the second electrode assemblie 230b is located in the second hole 224b.Each electrode assemblie 230a, 230b preferably make up in the above-mentioned mode about electrode assemblie 130 and form.Particularly, the first electrode assemblie 230a comprises the first electrode 232a, and this first electrode 232a has the first electrode front-face 236a, and the second electrode assemblie 230b comprises the second electrode 232b, and this second electrode 232b has the second electrode front-face 236b.
This agent structure 210 preferably includes through hole that holds evacuation tube and the threaded hole of admitting electric connection.These elements do not illustrate in Fig. 6; Yet these elements are corresponding to the like shown in Fig. 3.
As indicated above assembles this CDG 200 like that about CDG 100, make this barrier film 220 be striden across the front surface 212 of agent structure 210 by prestretched, and the cavity between the inside surface of barrier film 220 and this front surface 212 is evacuated and seals.
Comprising the second electrode assemblie 230b in CDG 200 is particularly advantageous when using the barrier film of larger diameter.Because the temperature around the CDG200 rises, pad 222 trend towards expanding and make barrier film 220 away from this adjoining front surface 212 of the front surface 236a of the first electrode 232a.Like this, the electric capacity between the first electrode 232a and the barrier film 220 can be along with temperature change.Make a distinction because the electric capacity that is not easy to be caused by temperature changes with the electric capacity change that is caused by pressure, therefore the electric capacity of being surveyed can not be expressed this pressure exactly.
Because the position of the second electrode assemblie 230b is close to the periphery of barrier film 220, and barrier film 220 is fixed to this front surface 212 at its periphery place via pad 222, so the pressure-dependent change in interval between the front surface 236b of this part barrier film 220 and the second electrode 232b is very little.Yet the temperature variant change in interval between the front surface 236a of the interval between the front surface 236b of the barrier film 220 and the second electrode 232b and the barrier film 220 and the first electrode 232a is substantially the same.Therefore, the electric capacity change that is caused by temperature variation is substantially the same for two electrodes.So, measure and when the electric capacity measurement that obtains between the barrier film 220 and the second electrode 232b is used at mensuration pressure, compensate this temperature effect in the electric capacity that obtains between the barrier film 220 and the first electrode 232a.
The present invention can also be with other special shape specific implementation, and does not depart from essential characteristic as described herein.It is just illustrative that embodiment mentioned above thinks in all fields, and do not have the restricted of any way.Scope of the present invention shows by claims subsequently, rather than shows by description above.All be considered in its scope in intension of equal value of claims and any the changing in the scope with institute.
Claims (12)
1. electric capacity diaphragm manometer comprises:
Agent structure with front surface and rear surface;
Pass at least one electrode that this agent structure is arranged, this electrode has and the concordant basically leading surface of described front surface;
Be arranged in the annular gasket on the front surface of described agent structure, this pad has a thickness; With
Barrier film with first surface and second surface, this first surface be arranged on the described pad and the front surface of thickness by pad and described agent structure spaced apart, this barrier film is fixed under extended state on the described pad, and the second surface of this barrier film is complete smooth and unobstructed exposed surface.
2. electric capacity diaphragm manometer according to claim 1, wherein, described electrode comprises:
Forward part, this forward part includes the material that is chosen to have first thermal expansion character, and described first thermal expansion character is similar to the thermal expansion character of described pad; With
The rear section, this rear section includes the material that is chosen to have second thermal expansion character, and described second thermal expansion character is lower than described first thermal expansion character.
3. electric capacity diaphragm manometer according to claim 1, wherein:
Described front surface has flat basically core, and this pad comprises the raised perimeter portion on the border that defines described front surface, and this raised perimeter portion has the thickness perpendicular to described flat core;
This first surface be arranged on the described raised perimeter portion and the front surface of thickness by described raised perimeter portion and described agent structure spaced apart, this barrier film is fixed on the described raised perimeter portion under extended state.
4. electric capacity diaphragm manometer according to claim 3 wherein, when barrier film being fixed on the described raised perimeter portion, is fixed to described raised perimeter portion on the front surface of described agent structure.
5. electric capacity diaphragm manometer according to claim 1, wherein:
Described front surface has flat basically core, and this pad comprises the raised perimeter portion on the border that defines described front surface, and this raised perimeter portion has the thickness perpendicular to described flat core;
This at least one electrode comprises: have first electrode of cylinder-shaped body, the position of described first electrode is near the center of described front surface, and the leading surface of described first electrode has a size and a shape; With second electrode with cylinder-shaped body, the position of described second electrode is adjacent to the periphery of described front surface, and the leading surface of described second electrode has the size and dimension substantially the same with the size and dimension of first electrode; With
This first surface be arranged on the described raised perimeter portion and the front surface of thickness by described raised perimeter portion and described agent structure spaced apart, this barrier film is fixed on the described raised perimeter portion under extended state.
6. electric capacity diaphragm manometer according to claim 5, wherein, each in first electrode and second electrode all comprises:
Forward part, this forward part includes the material that is chosen to have first thermal expansion character, and described first thermal expansion character is similar to the thermal expansion character of described raised perimeter portion; With
The rear section, this rear section includes the material that is chosen to have second thermal expansion character, and described second thermal expansion character is lower than described first thermal expansion character.
7. method of constructing the electric capacity diaphragm manometer comprises:
One electrode assemblie is mounted to passes a hole, this hole extends to the rear surface from the front surface of agent structure;
The annular gasket that will have an overall diameter is located on the front surface of this agent structure, and this pad has a thickness;
Barrier film is located on this pad, and this barrier film has first surface and second surface, this first surface contact with this pad and the front surface of the thickness by this pad and this agent structure spaced apart;
Heat this barrier film so that this membrane becomes expanded;
When membrane becomes expanded, the periphery of the first surface of this barrier film is welded on the pad, and this pad is welded on the front surface of agent structure, the periphery with the first surface of this barrier film is constrained to the size consistent with the overall diameter of pad therefrom; With
Cool off this barrier film so that this barrier film shrinks, and this barrier film is become by prestretched by the restriction on the periphery that is applied to this barrier film first surface by this pad.
8. method according to claim 7 wherein, applies a removable coating and heats described barrier film by applying emittance to this coating by the second surface to described barrier film.
9. method according to claim 7 wherein, forces described barrier film to form with described pad by the pressure that comes from press and contacts, and forces described pad to form contact against the front surface of described agent structure.
10. method according to claim 9, wherein, with reusable tool holder described barrier film is supported in the described press, the fusing point of this tool holder is high enough to make that than the fusing point of described barrier film, described pad and described agent structure described tool holder is not soldered on the barrier film when welding described barrier film, described pad and described agent structure.
11. method according to claim 7, wherein:
The front surface of described agent structure has flat basically core, and this pad comprises the raised perimeter portion on the border that defines described front surface, and this raised perimeter portion has perpendicular to the thickness of described flat core and has an overall diameter;
Barrier film is located on the described raised perimeter portion, this first surface contact with this raised perimeter portion and the front surface of the thickness by this raised perimeter portion and this agent structure spaced apart;
Wherein when membrane becomes expanded, the periphery of the first surface of this barrier film is welded on the described raised perimeter portion, the periphery with the first surface of this barrier film is constrained to the size consistent with the overall diameter of described raised perimeter portion therefrom; With
When wherein cooling off this barrier film, this barrier film is become by prestretched by the restriction on the periphery that is applied to this barrier film first surface by described raised perimeter portion.
12. method according to claim 11, wherein, this method also is included in when being welded to barrier film on the described raised perimeter portion, described raised perimeter portion is welded on the front surface of described agent structure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US45697503P | 2003-03-22 | 2003-03-22 | |
| US60/456,975 | 2003-03-22 | ||
| US10/249,238 | 2003-03-25 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101250776A Division CN101358889B (en) | 2003-03-22 | 2004-03-17 | Capacitance manometer and construction method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1791790A CN1791790A (en) | 2006-06-21 |
| CN100414278C true CN100414278C (en) | 2008-08-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101250776A Expired - Fee Related CN101358889B (en) | 2003-03-22 | 2004-03-17 | Capacitance manometer and construction method thereof |
| CNB2004800137583A Expired - Fee Related CN100414278C (en) | 2003-03-22 | 2004-03-17 | Capacitance manometer having a relatively thick flush diaphragm under tension to provide low hysteresis |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101250776A Expired - Fee Related CN101358889B (en) | 2003-03-22 | 2004-03-17 | Capacitance manometer and construction method thereof |
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| Country | Link |
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| CN (2) | CN101358889B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102631029B (en) | 2009-09-18 | 2015-01-14 | 卓智微电子有限公司 | Electronic cigarette and detector for air direction and air flow of electronic cigarette |
| US10420374B2 (en) | 2009-09-18 | 2019-09-24 | Altria Client Services Llc | Electronic smoke apparatus |
| SG182731A1 (en) * | 2010-02-02 | 2012-08-30 | Mks Instr Inc | Capacitive pressure sensor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4141252A (en) * | 1977-11-04 | 1979-02-27 | Lodge Arthur S | Flush pressure transducers for measuring pressures in a flowing fluid |
| US4542435A (en) * | 1984-03-29 | 1985-09-17 | General Signal Corporation | Pressure transducer and mounting |
| US5656780A (en) * | 1996-03-28 | 1997-08-12 | Kavlico Corporation | Capacitive pressure transducer with an integrally formed front housing and flexible diaphragm |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4578735A (en) * | 1984-10-12 | 1986-03-25 | Knecht Thomas A | Pressure sensing cell using brittle diaphragm |
| US5442962A (en) * | 1993-08-20 | 1995-08-22 | Setra Systems, Inc. | Capacitive pressure sensor having a pedestal supported electrode |
-
2004
- 2004-03-17 CN CN2008101250776A patent/CN101358889B/en not_active Expired - Fee Related
- 2004-03-17 CN CNB2004800137583A patent/CN100414278C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4141252A (en) * | 1977-11-04 | 1979-02-27 | Lodge Arthur S | Flush pressure transducers for measuring pressures in a flowing fluid |
| US4542435A (en) * | 1984-03-29 | 1985-09-17 | General Signal Corporation | Pressure transducer and mounting |
| US5656780A (en) * | 1996-03-28 | 1997-08-12 | Kavlico Corporation | Capacitive pressure transducer with an integrally formed front housing and flexible diaphragm |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101358889A (en) | 2009-02-04 |
| CN1791790A (en) | 2006-06-21 |
| CN101358889B (en) | 2011-06-08 |
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