CN1016727B - Method for making electrode of electromagnetic flowmeter - Google Patents
Method for making electrode of electromagnetic flowmeterInfo
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- CN1016727B CN1016727B CN 88108876 CN88108876A CN1016727B CN 1016727 B CN1016727 B CN 1016727B CN 88108876 CN88108876 CN 88108876 CN 88108876 A CN88108876 A CN 88108876A CN 1016727 B CN1016727 B CN 1016727B
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Abstract
A method to produce electrical flowmeter, including inserting the electric parts to a couple of plug jacks which are opposite to each other. The plug jacks are through annular wall of tube making of ceramic materials, heating and solidifying said electric parts to form electrode.
Description
The present invention relates to a kind of method of making electrode of electromagnetic flowmeter, specifically, relate to a kind of manufacture method that is used in the electrode in the electromagnetic flowmeter with ceramic measuring tube.
The routine measurement pipe that is used for electromagnetic flowmeter is made with stainless steel etc., and the inside surface of this pipe is coated with the insulation lining.But in recent years, developed a kind of rely on sintering as the stupalith of non-conducting material (as aluminium oxide Al
2O
3) and the measuring tube made.This measuring tube is compared with the common metal measuring tube with lining has higher corrosion stability, and does not at high temperature have deformation.In addition, can casting electrode in this measuring tube etc.Therefore, this measuring tube with plurality of advantages is widely used.Multiple structure has been proposed as the electrode structure that utilizes the electromagnetic flowmeter of this ceramic pipe.An example that discloses this structure in 58-501552 number is disclosed at Jap.P..Shown in Fig. 1 a and 1b, in this structure, form pair of opposed electrodes jack 3 at the middle part of the perisporium of the cylindrical moulded body of making by non-sintered ceramic material (as oxide ceramics) 4.Electrode 1 is inserted in the electrode jack 3, make the inside of its inner towards moulded body 4.In this case, at about 1800 ℃ of following sintering moulded bodies 4,, meanwhile, make electrode 1 overall fixed in electrode jack 3 by sintering to obtain measuring tube.Stupalith shrinks (at Al during promptly owing to sintering
2O
3Situation under shrink 17-20% approximately).Electrode 1 just forms an integral body with measuring tube 4, and obtains the fluid tightness of electrode jack 3.Utilize noble metal (as platinum or platinum alloy) to make electrode material, this is because these metals have the thermotolerance of gratifying anti-stupalith sintering temperature and have the thermal expansivity close with ceramic thermal expansivity.
The a pair of field coil that is installed on measuring tube 4 outside surfaces of reference number 5 expressions.
But (wherein electrode 1 is inserted in the unsintered ceramic moulded body 4 according to above method, and utilize sintering with electrode 1 overall fixed on measuring tube, so that make electrode jack 3 sealings reliably), the necessary strict dimensional tolerence of setting between electrode 1 and the jack 3, and the inside surface of the peripheral surface of each electrode 1 and each electrode jack 3 must have predetermined surfaceness or higher (being that surface undulation must be fine and closely woven).But, because electrode jack 3 without sintering the comparison fragility, so be difficult to sustain, so just caused various manufacturing step and lower output for obtaining the machining that required surfaceness is carried out.In addition, when electrode 1 inserted in the unsintered electrode jack 3, the inside surface in hole was easy to damage.So, must SC in installation process.And the shrinkage factor of stupalith when sintering be because of in batches, even if perhaps with a collection of and because of the difference of the manufacturing time influence of the temperature or the humidity of season or weather (especially because of) different.For this reason, in each sintering step, the external diameter of necessary strict control electrode 1 and the aperture of electrode jack 3.If dimensional tolerence is inappropriate, then fixing the or fluid tightness of electrode 1 can defectiveness, or because effect measuring tube 4 fractures of stress or damage during sintering.
Therefore, fundamental purpose of the present invention provides a kind of manufacture method of electrode of electromagnetic flowmeter, in this way, fixed electorde and obtain the fluid tightness of electrode jack reliably, can obtain not the measuring tube that the stress can be because of sintering the time ruptures or damages, increase the degree of freedom of selecting electrode material.
In order to reach the above purpose of the present invention, a kind of method of making electromagnetic flowmeter is provided, this method includes following steps: electrod assembly is inserted and insert a pair of perisporium that passes the measuring tube of being made by sintered ceramic material from outside to inside, and in the patchhole, electrod assembly is heated and solidifies to form electrode opposed to each other.
Fig. 1 a and Fig. 1 b are respectively the sectional view of measuring tube major part and the sectional view of amplification, show the structure of understanding conventional electrodes;
Fig. 2 is the sectional view of measuring tube major part, shows the method for making electrode of electromagnetic flowmeter according to the embodiment of the invention of understanding;
Fig. 3 a, 3b and 3c are respectively the sectional views of other electrode embodiment;
Fig. 4 is the sectional view of measuring tube major part, shows clear another embodiment of the present invention;
Fig. 5 a, 5b, 5c and 5d are respectively the sectional views of other embodiment of explanation electrode centers part;
Fig. 6 is the sectional view of measuring tube major part, shows clear further embodiment of this invention;
Fig. 7 a-7e is the sectional view of other other embodiment of electrode centers part;
Fig. 8 is the sectional view of measuring tube major part, shows clear further embodiment of this invention;
Fig. 9 and 10 is respectively the major part sectional view, shows other other embodiment that understands electrode;
Figure 11 is the major part sectional view of measuring tube, shows clear further embodiment of this invention;
Figure 12 a to 12d shows other other embodiment that understands electrode.
Fig. 2 is the sectional view with the electrode of the electrode manufacturing method manufacturing of the embodiment of the invention.With reference to Fig. 2, reference number 14 is represented by stupalith (as Al
2O
3Or ZrO
2) measuring tube made.A pair of field coil (see that Fig. 1 a) is placed on the outside surface of measuring tube 14, vertically clip measuring tube 14, thus with the perpendicular direction of the flow direction of the conductive liquid to be measured 16 of the measuring tube 14 of flowing through on produce a magnetic field.Pair of electrodes jack 13A and 13B are formed on the peripheral wall middle part of measuring tube 14, and they are opposed mutually on the direction perpendicular to the flow direction of testing liquid 16 and the magnetic direction that produces perpendicular to field coil.Electrode 11A and 11B put into electrode jack 13A and 13B respectively.Because electrode 11A and 11B have same structure, only describe electrode 11A below.Make electrode 11A by metallization by the various pastes of the conductive material formation of kind of liquid decision.If need corrosion resistivity, then adopt the metal powder paste that constitutes by platinum, gold etc. as electrode.If do not need corrosion resistivity, then Mo-Mn base paste, W base paste, Ag-Pd base paste, Ag-Pt base paste and Ag paste etc. are used for electrod assembly.The inner face 11a of electrode 11A is towards the inside of measuring tube 14, and to form the liquid surface in contact, its outer face 11b is fixed on the end of signal lead 20A.
The method of manufacturing with upper electrode arrangement is described below.At first, use stupalith (as Al
2O
3) form cylindrical moulded body.Utilize conventional method,, can form moulded body expediently, make this moulded body become measuring tube 14 by sintering by to powdery non-sintered ceramic material external pressurized or full pressurization together.At this moment, the formation of electrode jack 13A and 13B will be considered the contraction that takes place in the sintering step below.But, can behind sintering, grind and form electrode jack 13A and 13B.The molding that obtains as described above at predetermined temperature (at Al
2O
3Situation under be about 1800 ℃) following sintering, to obtain measuring tube 14.
When finishing the sintering step of measuring tube 14, electrode jack 13A and 13B process machining are to obtain required aperture and surfaceness.In the electrode jack 13A of measuring tube 14 and 13B, insert a kind of paste.In this case, measuring tube 14 is heated preset time (when being the platinum paste as if paste, at about 1000-1200 ℃, the time is 10-30 minute) at predetermined temperature.As a result, paste is sintered in electrode jack 13A and 13B, forms electrode 11A and 11B respectively.At this moment, the organic principle in the paste is evaporated or burns.If the one-period process can not be satisfactory (for example, because of thermal contraction produces recess), then can insert the paste of same type once more and make its metallization.
After forming electrode 11A and 11B, with signal lead 20A(20B) an end be connected to electrode 11A(11B) the outer end, field coil is installed to as shown in Figure 1 on the outside surface of measuring tube 14, finish measuring tube 14 thus.
Fig. 3 a to 3c shows the electrode 11A(11B that is used to increase the liquid surface in contact) change shape.With reference to Fig. 3 a, stretch into measuring tube 14 as the dome-type extension 11d of the inner.In Fig. 3 b, inner end portion is made the conical portion of widening towards measuring tube 14 inside.In Fig. 3 c, the inner is made into plate-like part 11f.By this way, can make the various shapes that change to the shape of electrode.
According to the method for above manufacturing electrode structure, after measuring tube 14 is sintered, paste is inserted electrode jack 13A and 13B and metallization within it, to form electrode.Like this, the back processing of electrode jack 13A and 13B be can carry out, or if necessary, can electrode jack 13A and 13B be formed in sintering measurement pipe 14 backs.As a result, can obtain required aperture and surfaceness, solve owing to batch difference or the different variation issue that cause of manufacturing time.In addition, because be sintered electrode 11A and 11B after sintering measurement pipe 14, so if desired, but sintered electrode 11A and 11B many times.Like this, can obtain the fluid tightness of electrode jack 13A and 13B reliably, to avoid the leakage of testing liquid 16.Because the sintering temperature of electrode 11A and 11B is only determined according to the paste material that uses, so needn't consider the sintering temperature of measuring tube 14.Therefore, owing to select the degree of freedom of electrode material to increase, so can adopt more cheap material.In addition, compare with conventional manufacture method (wherein, carrying out integral sintered with electrode 11A with 11B unsintered measuring tube when sintered electrode), measuring tube 14 shrinks hardly, only has the contraction of paste to produce little stress.Thus, can reduce or avoid the fracture or the damage of measuring tube 14.In addition, even if it needs owing to for example wearing and tearing to change and can not change with the integral sintered electrode of measuring tube.But the method according to this invention is because electrode 11A and 11B can rely on interpolation and sintering paste to change, so measuring tube itself just needn't be changed.
Make the method for electrode of electromagnetic flowmeter according to the present invention, first sintered ceramic measuring tube is inserted paste the electrode jack of measuring tube then, and metallizes within it to form electrode, thus, has increased the degree of freedom of selecting the electrode material kind.In addition, because independent sintering measurement pipe, thus the stress that produces at place, electrode installation position can reduce sintering the time, and the stress that produces when therefore reducing the electrode sintering, thus avoid the fracture or the damage of measuring tube.And, even cause change in size, also can carry out back processing owing to difference or manufacturing time are different in batches, with the required size precision and the surfaceness of acquisition electrode jack, thereby improve output.In addition, owing to can carry out the electrode sintering of any number of times if necessary, so can obtain reliable fluid tightness.Like this, just, can make high performance electrode structure expediently with very low expense.
Fig. 4 shows another embodiment of the present invention.With reference to Fig. 4, reference number 30 expressions are by for example Al
2O
3Or ZrO
2The ceramic measuring tube of making.A pair of field coil (is seen that Fig. 1 a) is installed on the outside surface of measuring tube 30, is vertically clipped measuring tube 30, and produce magnetic field on the direction vertical with the flow direction of conductive liquid 31 to be measured.With the middle part that pair of electrodes 32A and 32B insert measuring tube 30 perisporiums, opposed mutually on direction perpendicular to the flow direction of testing liquid 31 and the magnetic direction that produces perpendicular to field coil, obtain the electromotive force that produces in the testing liquid 31 thus.
Because electrode 32A and 32B have same structure, only describe electrode 32A below.Electrode 32A is made of stick electrode core 32a and metal level 32b, this electrode centers part and measuring tube 30 similar by stupalith (as Al
2O
3Or ZrO
2) make, and be inserted among the electrode jack 33A, this metal level 32b utilizes sintering to be formed on the circumferential surface and internal end surface of electrode centers part 32a, makes electrode jack 33A sealing.Electrode centers part 32a forms liquid contact surface towards the inside of measuring tube, and its outer end is connected to the end of signal lead 34A by cap 35A.
The manufacture method of the above electrode structure is described below.At first, use stupalith (as Al
2O
3) make unsintered measuring tube (being moulded body).Rely on the conventional method external pressurized or entirely with compressing powdery non-sintered ceramic material, can obtain this moulded body expediently, at this moment, consider the contraction that occurs in the following sintering step, form electrode jack 33A and 33B.But can form electrode jack 33A and 33B by the grinding after sintering.With moulded body sintering under about 1800 ℃ sintering temperature of making as described above, to form measuring tube 30.
After the sintering step of finishing measuring tube 30, with form the identical mode of measuring tube, utilize stupalith (as Al
2O
3) form the not core of sintered electrode, then this core is carried out sintering under about 1800 ℃ sintering temperature, to form electrode centers part 32a.After sintering, if necessary, measuring tube 30 and electrode centers part 32a are ground, to obtain required size and surfaceness.Then, the metal powder paste is coated in the electrode jack 33A(33B of measuring tube 30) inside surface on and on the surface of electrode centers part 32a.
If testing liquid 31 is acid or alkali, then electrode 32A and 32B must have corrosion resistivity, thereby adopt the metal powder paste that is made of platinum, gold etc.If corrosion resistivity need not arranged, then available Mo-Mn paste, W base paste, Ag-Pd base paste, Ag-Pt base paste, Ag paste etc. are as electrod assembly.The electrode centers part 32a that is coated with the platinum paste is inserted the electrode jack 33A(33B of the ceramic measuring tube 30 that sintering crosses) in.In this case, measuring tube 30 is heated (metallization) schedule time under about 1100 ℃ of temperature.Because the organism of paste is evaporated or burns, paste just becomes and is thin metal layer 32b.Rely on this metal level 32b, electrode centers part 32a sintering is at electrode jack 33A(33B) in, jack 33A(33B) sealed.
After this,, field coil is installed on the outside surface of measuring tube 30, thus, finishes measuring tube 30 being installed on the outer end of electrode 32A and 32B by metal or by cap 35A and 35B that metal and insulating material constitute.
According to above-mentioned electrode manufacturing method, measuring tube 30 and electrode centers part 32a be sintering independently of each other, paste is coated in electrode centers part 32a to be gone up and electrode jack 33A(33B) on, then core 32a is inserted, and utilizes sintering to make it be fixed on electrode jack 33A(33B) in.Like this, measuring tube 30 can stand machining with electrode centers part 32a behind sintering plain metal sintering.Exactly, electrode jack 33A and 33B can have precision and the surfaceness that obtains in plain metal is made, thereby solve because of batch difference or the different offset issue that cause of manufacturing time.In addition, when electrode centers part 32a inserted in the hole, electrode patchhole 33A and 33B can not damage.Like this, owing to rely on metal level 32b can carry out sintering/fixing and electrode jack 33A(33B of electrode centers part 32a reliably) sealing, so can prevent the leakage of testing liquid 31.And, owing to carry out sintering in advance, the amount of contraction during electrode centers part 32a sintering is little, and compares with conventional manufacture method (wherein measuring tube with electrode by integral sintered), the electrode place only produces little stress, can reduce or avoid breaking or damaging of measuring tube 30 thus.Moreover, even if need owing to for example wearing and tearing to change and can not change with the integral sintered electrode of measuring tube.But in the methods of the invention, rely on heating, make its fusing, just can change electrode centers part 32a, so that effectively utilize measuring tube 30 to metal level 32b.
Fig. 5 a to 5d shows several shapes that change, and wherein external diameter has localized variation with respect to the position of electrode centers part 32a.In Fig. 5 a and 5d, the diameter of outer end portion increases, and forms the outside core that inserts.In Fig. 5 b and 5c, the diameter of inner end portion increases, and forms the inner core that inserts.In Fig. 5 a and Fig. 5 b, electrode jack 33A(33B) diameter is even on whole length direction.In Fig. 5 c and 5d, at electrode jack 33A(33B) inside and outside open end form position 37 and 38 respectively, make the major diameter of electrode centers part 32a partly be arranged in position 37 or 38.Inside shown in Fig. 5 b or the 5c is inserted electrode centers part 32a and is had bigger liquid surface in contact, thereby helps measuring low different electrical testing liquid.
Fig. 6 shows by platinum (or platinum alloy) and makes and rely on platinum powder end paste (or platinum alloy powder paste) sintering/fixing electrode centers part 32a.In this case, because electrode centers part 32a itself is made by conductive material, the surface upward applies platinum powder end paste (or platinum alloy powder paste) so only need around, and needn't apply at the liquid surface in contact.In addition, embodiment is such as shown in Figure 4, and the sintering step of electrode centers part 32a carries out after ceramic measuring tube 30 is sintered.Corrosion resistivity is arranged if desired, and then platinum paste (or platinum alloy powder paste) preferably contains more Pt(weight ratio more than or equal to 85%).If do not need corrosion resistivity, then the content of Pt can be less.
Fig. 7 a-7e represents to have difform metal electrode core 32a, and in Fig. 7 a, electrode centers part 32a is a cylindrical part that has the end, and its outer end is an opening.In Fig. 7 b, electrode centers part 32a forms a disc-shaped part and increases liquid contact surface and accept hydraulic pressure, and is outstanding to the outside from the outside surface of measuring tube 30 with the integrally formed bar-shaped current-carrying part 32c of electrode centers part 32a.In Fig. 7 c, at electrode jack 33A(33B) outer opening end form a bellmouth 39 obtaining compressive property, and bellmouth 39 is covered by metal level 32b.In this case, after metal parts inserts jack, fill metal at tapering part.In Fig. 7 d, electrode centers part 32a outer end diameter increases, and makes it to come keeper electrode core 32a greater than the diameter of jack, shown in Fig. 5 a.In Fig. 7 e, electrode jack 33A(33B) be taper.And the insertion end of electrode centers part 32a also forms taper.Except above-mentioned variation, as the shape of electrode centers part 32a, jack also can have various other variations.
Method according to the electrode of the manufacturing electromagnetic flowmeter of the invention described above, cylindrical moulded body is made by the non-sintered ceramic material, and its sintering made ceramic measuring tube, then, be coated in paste in the electrode jack that the measuring tube circumferential surface forms and on the circumferential surface of electrode centers part.Electrode centers partly is inserted in the electrode jack, and by making the paste metallization that it is sintered to fix in jack.Therefore fixed electorde and make the electrode jack sealing reliably is to prevent leak of liquid to be measured.In addition, because electrode is to carry out sintering later on again at the sintering measurement pipe, so select the degree of freedom of electrode material to increase.And, because independent sintering measurement pipe, thus stress that produces at the electrode place can reduce sintering time the and the stress that produces when therefore reducing the electrode sintering, thus avoid breaking or damaging of measuring tube.Moreover, because in batches or manufacturing time difference when change in size occurring, can carry out aftertreatment, form and have the electrode jack of required size precision and surfaceness, thereby improve yield rate.Its result can easily go out high-performance electrode with low-cost production.
Fig. 8 represents another embodiment of the present invention.With reference to figure 8, reference number 50A and 50B represent respectively by making paste metallization as conductive material sintering formed metal level on the electrode jack 43A of measuring tube 40 and 43B inside surface.51A and 51B are respectively the brazing filler metal parts and are used for making electrode 41A and 41B to be connected on metal level 50A and the 50B.52A and 52B are respectively cap, and cap is connected to the end of signal extension line 53A and 53B and is installed in the outer end of electrode 41A and 41B respectively.
Because electrode 41A and 41B have same structure, so, only describe electrode 41A below.Electrode 41A is made of electrode body 41a and metal level 41b, and wherein electrode body 41a is similar to measuring tube 40 by sintered ceramic material Al for example
2O
3Form, metal level 41b is by a kind of paste sintering of being made up of conductive material is formed on the circumferential surface of electrode body 41a and inner face.The conductive material that forms metal level 41b is selected according to the kind of testing liquid, if promptly electrode 41A must have corrosion resistance, then should use the metal powder paste of platiniferous, gold or analog.If the corrosion resistance of not requiring then can be used Mo-Mn base paste, W base paste, Ag-Pd base paste, Ag-Pt base paste, Ag paste etc. is used for electronic unit.Metal level 41b and electrode body 41a be sintering formation integrally together.After electrode body 41a sintering, a kind of desired paste is coated on the electrode body 41a on the other hand, heating and sintered electrode main body 41a form metal level 41b.
With electrode 41A(41B) metal level 41b similar, if the metal level 50A and the 50B that form on electrode jack 43A and 43B inside surface also must have corrosion resistance separately, then should apply the metal powder paste that contains platinum, gold etc. with sintering, otherwise can apply and sintering Mo-Mn base paste W base paste etc.
Brazing filler metal parts 51A and 51B can adopt fusing point (500-600 ℃) to be lower than the conductive material of paste, silver solder alloy for example, these conductive materials of solder and gold silicon (gold silicon).
The manufacture method of above-mentioned electrode structure is described below.At first, by the non-sintered ceramic material for example, Al
2O
3, make cylindrical moulded body.Being sintered this moulded body that is used as measuring tube can pass through with conventional method Powdered non-sintered ceramic material external pressurized or the full formation easily with pressurization.At this moment, the formation of electrode jack 43A and 43B will be considered the contraction that takes place in following sintering step.Yet, can behind sintering, grind and form electrode jack 43A and 43B.As mentioned above the moulded body of Xing Chenging at predetermined temperature (at Al
2O
3Situation under be about 1,800 ℃) down sintering to be to obtain measuring tube 40.After the measuring tube sintering is finished,, can carry out machining to electrode jack 43A and 43B if need to obtain required aperture and surfaceness.
The metal powder paste is coated in the inside surface of electrode jack 43A and 43B, and at predetermined temperature to measuring tube heating preset time (being the platinum paste if metal powder is stuck with paste, then is 1,000-1,200 ℃, 10-30 minute) at interval.Its result, metal powder paste sintering forms thin metal layer 50A and 50B respectively in electrode jack 43A and 43B, and at this moment, the contained organic principle of metal powder paste is evaporated or burns.
Then, electrode 41A and 41B are inserted respectively among electrode jack 43A and the 43B, thereby their inner face is towards the inside of measuring tube 40.Electrode 41A(41B) thus preparation has electrode body 41a and a metal level 41b that sintering is crossed in advance.As electrode 41A(41B) insert electrode jack 43A(43B) time, the brazing filler metal parts 51A(51B of fusing) ostium 43A(43B), and cool off therein, solidify, thereby filled metal level 41b and 50A(50B) between the space.Its result, brazing filler metal parts 51A(51B) firmly electrode 51A(41B) be fixed on electrode jack 43A(43B) in, make electrode jack 43A(43B) sealing.In this case, brazing filler metal is to carry out under 250 ℃-600 ℃ in temperature.
After this, cap 52A and 52B are installed in the outer end of electrode 41A and 41B respectively and a pair of drive coil are contained in the outside surface of measuring tube, thereby finish measuring tube 40.
Method according to above-mentioned manufacturing electrode structure, behind the sintered ceramic measuring tube, electrode 41A(41B) insert and brazing filler metal at electrode jack 43A(43B) in, like this behind sintering to electrode jack 43A(43B) carry out machining to obtain required aperture and surfaceness.Thereby solved because batch difference or manufacturing time difference cause the problem that variation produces.In addition, if desired, the sintering of metal level 50A and 50B can carry out inferior arbitrarily.Because it carries out after measuring tube 40 is sintered.And, after sintering step, because brazing filler metal parts 51A(51B) fill and be fixed on electrode jack 43A(43B) in make it sealing, so can obtain reliable fluid tightness, thereby prevent that testing liquid 46 from leaking from electrode jack 43A and 43B.
Because the sintering temperature of metal level 50A and 50B is only according to material, promptly the composition of paste decides, thus do not consider the sintering temperature of measuring tube 40, thereby because the degree of freedom that material is selected has increased, then metal level 50A and 50B can be made by more cheap material.In addition, when sintered metal layer 50A and 50B and brazing filler metal electrode 43A and 43B, almost occur to shrink because at this moment measuring tube 40 sintering crossed.Therefore, compare, only produce a little stress, thereby reduce or avoid breaking or damaging of measuring tube 40 with conventional manufacture method (wherein measuring tube is integral sintered with electrode).Even and this and electrode that measuring tube is integral sintered is because the wearing and tearing or the analogue of electrode, they need be changed also and can't change.But the method according to this invention, electrode 41A and 41B can be changed by melting brazing filler metal parts 51A and 51B respectively.Therefore measuring tube 40 can repeatedly use.
Fig. 9 represents another embodiment according to electrode of the present invention.With reference to 9, one metal caps of figure 60A(60B) be contained in electrode 41A(41B) inner face be on the liquid contact surface 41C, thereby prevent wearing and tearing, corrosion of liquid contact surface 41C etc.Metal cap 60A and 60B on the civilian dress when making electrode 41A and 41B.In situation as shown in figure 10, one projection 60a being installed can be at metal cap 60A(60B) go up whole formation, and the liquid contact surface 41C that is assemblied in electrode body 41a goes up among the recess 41d that forms.
Other layout is identical with embodiment shown in Figure 8.
Figure 11 represents another embodiment, wherein the electrode 41A(41B that is made by platinum or platinum alloy) by brazing filler metal parts 51A(51B) insertion electrode jack 43A(43B).In this case, because electrode 41A(41B) itself make by conducting metal.So needn't form the metal level 41b among Fig. 8 embodiment.Therefore other layout and manufacture method specifically described in this omission with embodiment illustrated in fig. 8 identical.
Figure 12 a and 12b represent the difform electrode 41A(41B that is made of conductive material) change shape.In Figure 12 a and 12b, electrode 41B(41B) inner end forms a plate-like part 41e and a tapering part 41f, to increase liquid contact surface.In Figure 12 c, at electrode 41A(41B) the outer end form a major diameter part 41g.In Figure 12 d, electrode jack 43A(43B) be the taper that the inside towards measuring tube 40 narrows down, and electrode 41A(41B) also form taper.
As mentioned above, according to the method for the electrode of manufacturing electromagnetic flowmeter of the present invention, at first the sintered ceramic measuring tube inserts electrode in the electrode jack of measuring tube then, therefore, selects the degree of freedom of electrode material to increase.In addition, because the independent sintering of measuring tube, stress that place, electrode installation position produces in the time of can reducing sintering and the stress that produces when therefore reducing the brazing filler metal electrode, thus avoid breaking or damaging of measuring tube.And, even because the in batches different different change in size that occur with manufacturing time, also can obtain required size precision and surfaceness by electrode jack being carried out aftertreatment, thereby raising yield rate, in addition, because it is fixing that electrode is brazing filler metal, do not need high precision, can make electrode jack obtain sealing reliably by the brazing filler metal parts.Its result can easily produce the high-performance electrode structure with low cost.
Figure 13 represents another embodiment of the present invention, and with reference to Figure 13, reference number 74 representatives are by stupalith, as Al
2O
3Or ZrO
2The measuring tube of making.(see Fig. 1 a), measuring tube 74 vertically is clipped in the middle, this field coil produces the magnetic field perpendicular to the flow direction of the conducting liquid to be measured 76 that flows through measuring tube 74 at the outside surface of measuring tube 74 a pair of field coil to be set.Pair of electrodes jack 73A and 73B form at the center section of the perisporium of measuring tube 74; With all perpendicular direction of the magnetic direction that flow direction and field coil produced of testing liquid 76 on relative and put.Electrode 71A and 71B put into electrode jack 73A and 73B respectively.Because electrode 71A and 71B have same structure, only electrode 71A are described below.
Electrode 71A comprises the cylindrical metal layer 71b that paste metallized (sintering) forms as conductive material and is filled in brazing filler metal parts 71a in the metal level 71b on the inside surface of electrode jack 73A.The end of signal lead 72A links to each other with the outer end of metal level 71b.
The conductive material that is used to form metal level 71b can be selected arbitrarily according to the type of testing liquid.For example, if electrode 71A and 71B must have corrosion resistance, then should use the metal powder paste of platiniferous, gold or analog.If the corrosion resistance of not requiring, then Mo-Mn base paste, W base paste, Ag-Pd base paste, Ag-Pt base paste, Ag paste etc. can be used for electrod assembly.By required paste is coated in electrode jack 73A(73B) on the inside surface, and form metal level 71b at predetermined temperature sintering preset time (for the platinum paste is 1,000-1,200 ℃, 10-30 minute).At Al
2O
3Situation under, the sintering temperature of measuring tube 74 is 1,800 ℃.
Brazing filler metal material 71a can be lower than the conductive material of paste with fusing point, and as the silver solder alloy, solder and gold silicon etc., this conductive material are inserted metal level 71b and cooled off therein and solidify under molten state.In this case, the brazing filler metal temperature of above-mentioned conductive material (being silver solder alloy, solder, gold silicon) is respectively 500-600 ℃, about 200 ℃ and 300～400 ℃.
Figure 14 represents the shape that changes of electrode structure.With reference to Figure 14, form two flange 73a and 73b at two open ends of cylindrical metal layer 71b, and these two flange cap live electrode jack 73A(73B) the periphery of two open ends.As a result, the area of electrode inner face 71d (being that liquid contact surface is long-pending) increases, thereby obtains gratifying intensity with the resistance internal pressure at end face.
According to the electrode structure of above-mentioned layout, paste is inserted the electrode jack 73A(73B on the sintered ceramic measuring tube 74) in, and metallize to form cylindrical metal layer 71b, brazing filler metal parts 71a is filled in wherein to constitute electrode 71A(71B).Therefore, after sintering measurement pipe 74, can be as ordinary metallic material to electrode jack 73A(73B) carry out machining, thus the dimensional accuracy and the surfaceness that are obtained when obtaining to be similar to the processing ordinary metallic material.As a result, because batch difference or manufacturing time difference cause the problem of measuring tube 74 variations to solve.In addition, because only according to the material sintered metal layer 71b of used paste, so needn't consider the sintering temperature of measuring tube 74.Therefore, owing to select the degree of freedom of electrode material to increase, thus can use more cheap material, and if desired, the sintering of metal level 71b can repeat many times.Thereby electrode jack 73A and 73B can seal reliably, prevent that testing liquid 76 is from jack 73A(73B) inside surface and metal level 71b between leak.Further, because electrode 71A and 71B form in the measuring tube 74 that sintering is crossed, so when the paste sintering, the amount of contraction of measuring tube 74 is very little.Thereby, because the contraction of paste only produces very little stress, so can reduce or avoid breaking or damaging of measuring tube 74.In addition, in conventional structure, even with the integral sintered electrode 71A of measuring tube 74 and 71B since wearing and tearing or analogue need change and can not change.Yet, in the electrode structure of the present invention, can make electrode 71A(71B again by heating and molten metal layer 71b and brazing filler metal parts 71a), thus effectively utilize measuring tube 74.
Electrode 71A(71B) cross sectional shape is not to be restricted to as Figure 13, shown in 14, but can change shown in Figure 15 a-15d.These change identical with shown in Figure 12 a-12d, and it specifically describes in this omission.
As mentioned above, the electrode structure of electromagnetic flowmeter constructed in accordance, paste is applied on the electrode jack inside surface of the ceramic measuring tube behind the sintering, and make its metallization form the cylindrical metal layer, brazing filler metal parts are filled and are solidificated in wherein to form electrode, therefore fixed electorde and make the electrode jack sealing reliably is with the leakage that prevents testing liquid with increase the degree of freedom of selecting electrode material.In addition, when metal level metallizes, can reduce the stress that the electrode installation position place of measuring tube produces, thereby prevent breaking or damaging of measuring tube.And, owing to can carry out machining,, improve the rate that manufactures a finished product of measuring tube so can obtain required size precision and surfaceness to electrode jack.Its result can easily produce high performance electrode structure with low cost.
Claims (38)
1, a kind of method of making electrode of electromagnetic flowmeter comprises step:
The electrod assembly that paste is made inserts and is filled in a pair of jack respect to one another, and described jack passes the annular wall of the measuring tube of being made by sintered ceramic material from outside to inside,
Heating is also solidified described electrod assembly, to form electrode.
2, according to the process of claim 1 wherein that described each electrod assembly all made by the metal paste.
3, according to the process of claim 1 wherein that described each electrod assembly has a conical the inner.
4, according to the process of claim 1 wherein that described each electrod assembly has a disc the inner.
5, according to the process of claim 1 wherein that described each electrod assembly comprises a bar-like member, and the metal level that between the inside surface of a corresponding described jack and described bar-like member, forms.
6, according to the method for claim 5, wherein said metal level is after the circumferential surface coated with metal paste of described bar-like member, forms in the described jack by bar-like member is inserted into.
7,, wherein the metal cap that is connected to described metal level is installed in the outer end of described bar-like member according to the method for claim 5.
8, according to the method for claim 5, there is a big diameter outer end of wherein said bar-like member.
9, method according to Claim 8, wherein the outer openend at described each jack forms a seat, and the major diameter of described bar-like member part is installed on the described seat by described metal level.
10, according to the method for claim 5, the inner of wherein said bar-like member has a major diameter.
11, according to the method for claim 10, at seat of inboard openend formation of described each jack, and the major diameter of anti-described stick-like part is installed on the described seat by described metal level.
12, according to the method for claim 5, wherein said metal level is after coated with metal paste on the circumferential surface of described bar-like member and the inner face, forms in the described jack by bar-like member is inserted into.
13, according to the method for claim 5, wherein said bar-like member comprises that one has at the bottom of one and the cylindrical parts of an open outer end.
14, according to the method for claim 5, the outer end portion of wherein said jack is taper, and inserts brazing filler metal parts later in that the described bar-like member that was coated with described metal level is inserted described jack.
15,, wherein form a major diameter part that is used for respect to described jack location in the outer end of described bar-like member according to the method for claim 5.
16, according to the method for claim 5, wherein said jack is taper, and the distal end of described bar-like member is conical.
17, according to the method for claim 5, wherein said bar-like portion comprises a kind of stupalith.
18, according to the method for claim 5, wherein said bar-like member comprises metal parts.
19, according to the method for claim 5, wherein:
It is sufficiently large described jack in the external diameter of described electrod assembly,
After described electrod assembly inserted described jack, the low-melting brazing filler metal parts than described metal level are inserted wherein.
20, according to the method for claim 19, after forming second metal level on the inside surface of described jack, described electrod assembly is inserted wherein.
21, according to the method for claim 19, wherein after the metal paste is coated onto the circumferential surface of described bar-like member,, this bar-like member forms described metal level in the described jack by being inserted.
22, according to the method for claim 19, wherein, be embedded into described metal level in the described jack after, being connected to the outer end that metal cap on the described metal level is installed to described bar-like member.
23, according to the method for claim 19, wherein, the metal paste is coated onto after the circumferential surface and inner side end of described bar-like member, forms described metal level in the described jack by this bar-like member is inserted into.
24, according to the method for claim 23, wherein, metal cap is installed on the inner side end of described bar-like member by described metal paste.
25, according to the method for claim 19, wherein said jack is taper, and the distal end of described bar-like member is conical.
26, according to the process of claim 1 wherein that described each electrod assembly comprises bar-like member.
Sufficiently large each described jack in the size of described electrod assembly, and
After being inserted into described bar-like member in the described jack, low-melting brazing filler metal parts are inserted wherein.
27, according to the method for claim 26, wherein the outer openend at described jack forms a seat, and partly is installed on the described seat by the major diameter of described metal level with described bar-like member.
28, according to the method for claim 26, wherein the inner opening end parts at described jack forms a seat, and partly is installed on the described seat by the major diameter of described metal level with described bar-like member.
29, according to the method for claim 26, wherein said jack is taper, and the distal end of described bar-like member is conical.
30, according to the process of claim 1 wherein that described each electrod assembly comprises a metal parts and the low-melting brazing filler metal parts than described metal parts.
After forming the metal level of the described metal parts of one deck on the inside surface of described each jack, will insert wherein than the low-melting described brazing filler metal parts of described metal level.
31, according to the method for claim 30, wherein said metal level is made of a kind of metal paste.
32,, wherein has a chimb at the above metal level of the inner end edge of described jack according to the method for claim 30.
33, according to the method for claim 30, wherein said jack is taper in inner end portion.
34, according to the method for claim 30, wherein the inner opening end at described jack forms a seat.
35, according to the method for claim 30, wherein make a seat in the outer end portion of described jack.
36, according to the method for claim 30, wherein said jack is tapered from outside to inside.
37, a kind of method of making electrode of electromagnetic flowmeter comprises step:
Electrod assembly is inserted and is filled in a pair of jack respect to one another, and described jack passes the annular wall of the measuring tube of being made by sintered ceramic material from outside to inside;
Heating is also solidified described electrod assembly to form electrode;
Wherein said each electrod assembly comprises a metal layer at least.
38, a kind of manufacture method of electrode of electromagnetic flowmeter comprises:
A measuring tube that constitutes by sintered ceramic material, it has a pair of jack respect to one another, the annular wall of passing measuring tube from outside to inside;
Be installed in the electrode in the described jack;
Wherein, each described electrode comprises a metal layer at least, electrode securely soldering and sealing in the described jack of a correspondence.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP327358/87 | 1987-12-25 | ||
| JP327357/87 | 1987-12-25 | ||
| JP327359/87 | 1987-12-25 | ||
| JP32735787A JPH01169320A (en) | 1987-12-25 | 1987-12-25 | Manufacture of electrode part of electromagnetic flowmeter |
| JP14607/88 | 1988-02-08 | ||
| JP1460788U JPH01120622U (en) | 1988-02-08 | 1988-02-08 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1034995A CN1034995A (en) | 1989-08-23 |
| CN1016727B true CN1016727B (en) | 1992-05-20 |
Family
ID=26350576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88108876 Expired CN1016727B (en) | 1987-12-25 | 1988-12-24 | Method for making electrode of electromagnetic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1016727B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0308446D0 (en) * | 2003-04-14 | 2003-05-21 | Sentec Ltd | Low-power magnetic flow meter |
| CN102680033B (en) * | 2011-03-10 | 2014-04-23 | 上海威尔泰仪器仪表有限公司 | Method for manufacturing electrode member of electromagnetic flowmeter sensor |
| US9068869B2 (en) * | 2013-03-14 | 2015-06-30 | Rosemount Inc. | Magnetic flowmeter with bonded PTFE electrodes |
| JP7039276B2 (en) * | 2017-12-15 | 2022-03-22 | アズビル株式会社 | Electrode for detecting potential of electromagnetic flow meter |
-
1988
- 1988-12-24 CN CN 88108876 patent/CN1016727B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN1034995A (en) | 1989-08-23 |
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