Background technique
Valve is as one of main core parts of pressure piping, it is the important component part of pressure piping, be widely used in essential industry facility and urban lifeline engineerings such as petrochemical industry, combustion gas, metallurgy, electric power, in the development of the national economy and people's activity in production, brought into play important function.Adopt passivating technique at present, the valve that forms the stainless steel-like of anti-corrosion skin covering of the surface at the valve corrosion location is used in a large number.But these control valves still can produce corrosion in various degree, make valve be difficult for opening and closing after the valve corrosion, particularly passivating film destroys spot corrosion and the local etching that produces, have influence on sealability, the valve corrosion causes the material waste, increases energy consumption, cause valve leak, befouling environment causes taking place casualty accident, threatens safety in production.More than these situations all can bring in various degree economic loss.
At present, in existing patented technology, anticorrosion valve commonly used has following three classes mostly:
One class is by the improvement valve mechanism, and minimizing contacts with corrupt liquid.The patent No. is 95117085.6 Chinese invention patent, discloses a kind of leakage-less corrosion-resistant controllable valve, move by magnetic force control clack valve, thereby the closure or openness of control valve is not easy to wear; The patent No. is 90206833.4 Chinese utility model patent, a kind of corrosion-resistant improvement valve is disclosed, change whole valve rod into upper valve rod and lower valve rod two-part, and will be in seal ring and change with the rotation screw thread of upper/lower positions and be put on the upper valve rod, upper valve rod is in the above position of seal ring, improves the valve anti-corrosion capability.
Another kind of is to adopt new corrosion resistant material to improve the anti-corrosion capability of valve.The patent No. is 01141067.1 Chinese invention patent, disclose a kind of new structure ceramic valve, its valve seat and flap are all made with stupalith, seal with graphite packing between valve seat and the valve body, and fix by gland, by changing structure and adopting corrosion resistant material to improve the valve anti-corrosion capability; Number of patent application is 200710000292.9 Chinese invention patent, discloses a kind of high temperature resistant corrosion resistant high-strength graphite-carbon composite valve, and valve rod and spool adopt carbon carbon composite to make, and valve seat adopts graphite to make, and realizes anti-corrosion.
Also having a class is to add lining or the isolated corrupt liquid of coating at valve internal, and the patent No. is 90201262.2 Chinese utility model patent, discloses the anticorrosion valve of a kind of cast stone lining, sets up the cast stone lining and realize anti-corrosion in valve; The patent No. is 97233920.5 Chinese utility model patent, disclose a kind ofly high temperature resistantly, anti-wash away, anticorrosion valve, be transition layer to be set earlier, stupalith and plasticizer or self-melting alloy work lining are set on transition layer at valve gap, body cavity, closure member, valve base surface.
Though above-mentioned patent is in the anti-corrosion capability that has improved valve in varying degrees, all there is narrow limitation in each, and applicability is narrow, versatility is not strong, and the valve antiseptic effect that has is bad.
Summary of the invention
Technical problem to be solved by this invention is to overcome the shortcoming of above-mentioned valve, provide a kind of simple in structure, corrosion resistant performance good, applicability is strong, versatility is good, the anticorrosion valve of the band anodic protection of long service life.
The technical solution that solves the problems of the technologies described above employing is: first inner chamber and second inner chamber that are manufactured with mutual UNICOM in valve body, be manufactured with import a on the valve body with the first inner chamber UNICOM, outlet b with the second inner chamber UNICOM, valve seat is arranged on the passage of first inner chamber and the second inner chamber UNICOM, flap is arranged in the valve seat, the valve body top is provided with bonnet, the bottom is provided with bottom flange, valve rod is arranged in the bonnet by gland, the gland below sets gradually the gland that is enclosed within on the valve rod, pressure ring and support ring, the valve rod below is provided with flap, flap and bonnet, be provided with lining between the bottom flange, be respectively arranged with cathode sheets on the upper shaft of flap and the outer surface of lower shaft.
Cathode sheets of the present invention has 1-4, and cathode sheets is evenly arranged along the outer surface of flap upper shaft and lower shaft.
Cathode sheets of the present invention is titanium cathode sheets or platinum cathode sheet or stainless steel cathode sheet or carbon steel cathode sheets or cathode sheet or lead electrode sheet or graphite cathode sheet.
Because the present invention has adopted the outer surface in flap upper shaft and lower shaft that cathode sheets evenly is set, and has improved the antiseptic property of flap, has prolonged the working life of valve.The present invention compares with existing valve, has simple in structure, advantages such as corrosion resistant performance good, applicability is strong, versatility is good, long service life reasonable in design, can be used for the valve on corrosion liquid manufacturing mechanism and the conveyance conduit.
Embodiment
Below in conjunction with drawings and Examples the present invention is illustrated in further detail, but the invention is not restricted to these embodiments.
Embodiment 1
In Fig. 1,2,3, the anode protection anticorrosion valve of present embodiment is made of indicator panel 1, valve rod 2, gland 3, gland 4, pressure ring 5, support ring 6, bonnet 7, lining 8, valve body 9, cathode sheets 10, flap 11, valve seat 12, sealing gasket 13, bottom flange 14, plug 15 connections.
In the present embodiment, the tops in the valve body 9 are manufactured with first inner chamber, the bottom is manufactured with second inner chamber, and first inner chamber and second inner chamber link, and are manufactured with on the valve body (9) and the import a of the first inner chamber UNICOM, and the outlet b of the second inner chamber UNICOM.Valve body 9 tops are with the screw threads for fastening coupling bonnet 7 that has been fixedly connected, valve body 9 bottoms are with the screw threads for fastening coupling bottom flange 14 that has been fixedly connected, by being threaded plug 15 is installed on the bottom flange 14, between bonnet 7 and bottom flange 14 and the valve body 9 sealing gasket 13 is installed.Valve rod 2 tops are equipped with indicator panel 1 by scyewed joint, and valve rod 2 usefulness screw threads for fastening couplings and gland 3 are installed in the center hole of bonnet 7 and bottom flange 14, are set with gland 4, pressure ring 5, support ring 6 from top to down successively on the gland 3 below valve rods 2.Flap 11 is connected as a single entity with valve rod 2 and is positioned at the bottom of valve rod 2, between flap 11 and bonnet 7, the bottom flange 14 lining 8 is installed, valve seat 12 is installed on the UNICOM road between first inner chamber and second inner chamber by scyewed joint, flap 11 is arranged on the valve seat 12 and can moves along self axis, thereby realizes opening or closing valve.During valve open, import a, first inner chamber are opened by the path of valve seat 12 and second inner chamber and outlet b; During valve closing, path blockade between import a, first inner chamber and second inner chamber and the outlet b.
On the circumferential outer surface of the upper shaft of flap 11 and lower shaft, be welded with 3 cathode sheets 10 respectively, on the upper shaft that cathode sheets 10 also can adopt screw to be connected in to be installed in flap 11 and the circumferential outer surface of lower shaft, 3 cathode sheets 10 evenly distribute along the excircle of flap 11, and promptly the angle between the geometric center lines of the geometric center lines of a slice cathode sheets 10 and adjacent a slice cathode sheets 10 is 120 °.The big I of cathode sheets 10 carries out specifically determining according to valve internal circulation medium kind, flow and protected valve material; present embodiment cathode sheets 10 be the graphite cathode sheet; this material has electric conductivity preferably as electrode slices; cathode sheets 10 also can adopt any one in platinum cathode sheet, stainless steel cathode sheet, carbon steel cathode sheets, cathode sheet, the lead electrode sheet; specifically select that a kind of cathode sheets for use, should carry out specifically determining according to the material of medium kind, flow and the protected valve of valve internal circulation.
In order to improve working life of the present invention; with chemistry or electrochemical method passivation is carried out on bonnet 7, bottom flange 14, body cavity, flap 11, valve seat 12 surfaces; make above-mentioned parts form anti-corrosion skin covering of the surface; valve in use; part in cathode sheets 10 and the valve flowing channel space all is in the liquid; the potential difference of the part in cathode sheets 10 and the valve flowing channel space forms electric current, gives it with protection as the blunt electric current of dimension of keeping the part passivation in the valve flowing channel space.
Embodiment 2
In the present embodiment, be made into ring and be welded on respectively on the circumferential outer surface of the upper shaft of flap 11 and lower shaft being welded with 10,1 cathode sheets 10 of 1 cathode sheets on the circumferential outer surface of the upper shaft of flap 11 and lower shaft respectively.The size of cathode sheets 10 and the cathode sheets of selecting that a kind of material for use can carry out specifically determining according to valve internal circulation medium kind, flow and protected valve material.The connection of other component and component is identical about embodiment 1.
Embodiment 3
In the present embodiment, on the circumferential outer surface of the upper shaft of flap 11 and lower shaft, be welded with 4 cathode sheets 10 respectively, 4 cathode sheets 10 evenly distribute along the excircle of flap 11, and the angle between the geometric center lines of the geometric center lines of a slice cathode sheets 10 and adjacent a slice cathode sheets 10 is 90 °.The size of cathode sheets 10 and the cathode sheets of selecting that a kind of material for use can carry out specifically determining according to valve internal circulation medium kind, flow and protected valve material.The connection of other component and component is identical about embodiment 1.
Working principle of the present invention is as follows:
As shown in Figure 1, valve is in half-open position, and flowing medium enters first inner chamber of valve body 9 from inlet a, through the annular space of flap 11 with valve seat 12, enters second inner chamber of valve body 9 and flows out valve from outlet b.In this state, flowing medium is full of whole valve flowing channel space.Cathode sheets 10 is placed on the upper shaft of flap 11 and lower shaft both sides up and down; the current potential of cathode sheets 10 is higher than all parts in the whole valve flowing channel space: i.e. gland 4, pressure ring 5, support ring 6, bonnet 7, lining 8, valve body 9, flap 11, valve seat 12, bottom flange 14, plug 15; make above-mentioned parts be in the anodic protection state, be not subjected to the corrosion of flowing medium.And all component in the whole valve flowing channel of the present invention space all pass through passivation before use, under the high petential effect of cathode sheets 10, are easy to be in the anodic protection state.
By anodic protection; make the key position surface of valve internal keep and repair the passivated surface film; the protection valve material is not subjected to the corrosion of flowing medium; particularly can reduce passivating film and destroy spot corrosion and the local etching that is produced; increase the anti-impact erosion ability of valve, thereby prolong the working life of valve.
In order to verify beneficial effect of the present invention, the inventor adopts the anode protection anticorrosion valve of the embodiment of the invention 1 preparation to carry out laboratory test, and test situation is as follows:
Experimental drug: commercially available sodium chloride and potassium chloride (it is pure to be analysis, and Tianjin red rock chemical reagent factory produces); Distilled water: chemical reagent factory in Xi'an produces.
Laboratory apparatus: Corrtest electro-chemical test system, the Central China University of Science and Technology produces; Electrolytic cell, three-electrode electro Chemical test system, reference electrode and auxiliary electrode are saturated calomel electrode, platinum electrode, are produced by Shanghai Russell Science and Technology Ltd..
Preparation sample: 304 stainless steel test pieces, use 400# successively, the 800# liquid honing, the another side bonding wire is drawn lead, with this face and all the other corner epoxy sealings, uses acetone wiping oil removing before the experiment, after anhydrous alcohol dewaters, place exsiccator stand-by, its specification is Φ 16 * 3mm, and test area is 2.01cm
2304 passivation for stainless steel test pieces: the method with chemical passivation is carried out passivation with above-mentioned treated 304 stainless steel test pieces, with acetone wiping oil removing, after anhydrous alcohol dewaters, places exsiccator stand-by before the experiment.
Test method: 304 stainless steel test pieces, auxiliary electrode are inserted in the electrolytic cell, and reference electrode is put into the shell type salt bridge.The handshaking procedures of salt bridge is as follows: earlier solution to be measured is drawn into the outer sleeve of salt bridge and is full of it from the latex mouth of pipe by ear-cleaning ball; Getting the saturated KCl solution of 3mL is injected in the inner sleeve of salt bridge; Reference electrode is inserted with earlier in the latex mouth of pipe, fills in the inner sleeve of salt bridge then together and make it tight; Make interior hole solution unlikely by negative pressure by the leakage of porous core.
304 stainless steel test piece pitting potentials adopt electrokinetic potential scanning polarization curve to measure test method, and probe temperature is 40 ℃, and the employing mass fraction is 3.5% the NaCl aqueous solution.Connect power supply before the experiment and made the instrument preheating 20 minutes, and three-electrode system and corrosion test system are connected.It is 0.5-1cm under 3.5% the NaCl aqueous solution liquid level that test face through the polishing sample is immersed mass fraction entirely, places water-bath to keep 40 ℃ of temperature.Place after 10 minutes, treat to begin to carry out zeta potential scanning after sample reaches stable corrosion potential.Open analogue low pass filtering and the digital filtering of potentiostat in being provided with, be set at 20 seconds retard time.Initial potential is-100mV, and the termination current potential is 800mV (homogeneous phase is to OCP), and the speed of scanning is 60mV/min.
Adopt the pitting potential of electrokinetic potential scanning polarization curve measurement measurement of test method 304 passivation for stainless steel test pieces identical with 304 stainless steel test pieces.
Experimental result:
Reference standard GB/T17899-1999 " stainless steel pitting potential method of measurement " records the pitting potential before and after the passivation for stainless steel, as shown in Figure 4.
(1) polarization curve of 304 stainless steel test pieces before and after the passivation listed, pitting potential before the 304 stainless steel test piece passivation is-6mV, pitting potential after the passivation is up to 271mV, and the pitting potential after the 304 stainless steel test piece passivation is higher than the pitting potential before the passivation far away.
Passivation region scope before passivation region scope>passivation after (2) the 304 stainless steel test piece passivation, passivating film plays a very good protection.
The blunt current density of dimension before (3) the 304 stainless steel test piece passivation is 7.45 * 10
-7A/cm
2, the blunt current density of the dimension after the passivation is 1.28 * 10
-7A/cm
2, the blunt current density of dimension after the 304 stainless steel test piece passivation far away<the blunt current density of dimension before the passivation.
(4) 304 stainless steel test pieces are after passivation, and pitting potential is shuffled, and for 304 stainless steel test pieces provide bigger potential difference, increased the anodic protection effect of 304 stainless steel test pieces.