CN103021583B - Wet coating method for outer semiconducting layer of high-voltage cable sheath - Google Patents

Abstract

The invention discloses a wet coating method for an outer semiconducting layer of a high-voltage cable sheath. The method includes the steps: 1) using water and graphite for preparing graphite solution according to the mass percent of 1.5-2:1; 2) pouring the solution on the surface of the cable sheath at the temperature of 15-30 DEG C under the pressure of 0.18-0.28MPa; 3) uniformly spreading graphite through a sponge polishing mould; and 4) using a compressed air drier to dry the surface of the cable at an outlet of the sponge polishing mould. Graphite adhesive force is guaranteed without using organic adhesives and organic solvents in the graphite solution, the outer semiconducting layer is less prone to shed, production cost is saved, and operations are simple and convenient. Further, adhesive force is equivalent to that obtained with organic adhesives and organic solvents used in the graphite solution.

Description

Sheath of hv cable outer semiconducting layer wet coating process method

Technical field

The present invention relates to a kind of cable cover(ing) outer semiconducting layer wet coating process, particularly a kind of sheath of hv cable outer semiconducting layer wet coating process method.

Background technology

In high pressure, ultra-high voltage cross-linking cable manufacture process, for the security reliability of checking insulated type sheath, comprise the voltage test to insulated type sheath in delivery test project, therefore need in insulated type jacket outer surface coated with conductive coating to form the external electrode of crosslinked cable.

Current high pressure, extra-high-tension cable sheath outer semiconducting layer are adopted in two ways usually: one is coated with graphite, and another kind extrudes the formation of semiconductive jacket material to extrude semi-conductive layer.

Coated with graphite technique generally adopts dry-coated mode at present, and the graphite adhesive force of this method coating is bad, and graphite powder easily comes off, and causes production on-site environment very poor.In cabling process, there will be graphite to come off problem, not only pollute job site, if come off serious and carrying out smoothly of sheath withstand voltage test can be affected.Be exactly the identification of sheath lettering difficulty on the other hand, before coating, lettering is easily covered by graphite; And lettering is easily wiped after application, do not meet standard-required.

And extrude semi-conductive layer technique, need the thickness extruded to be 0.3 ~ 0.5mm, need to transform equipment, not only production cost is high, and production technology difficulty controls, and easily occurs the defect such as bottom pour ladle or broken hole.

In order to overcome above-mentioned defective workmanship, technical staff contemplates and adopts wet coating method graphite spraying.It is very dirty that wet coating method graphite spraying solves coating scene, and graphite such as to fly upward at the problem, and solve that to extrude semi-conductive layer explained hereafter cost high, and production technology difficulty controls, and easily occurs the problem such as bottom pour ladle or broken hole.

" 110kV crosslinked cable outer jacket manufactures new technology " (" electric wire " third phase in 2006, Liang Guohua) describe wet coating method in a literary composition, master operation is that graphite is mixed in volatile chemical reagent (acetone) with certain proportion is inner, cable surface is sprayed onto by water pump, through drying up, then carry out polishing by sponge polished die.

Publication number is that CN201439079U utility model patent discloses a kind of graphite powder coating device, equadag coating manufacturing process is also described: graphite powder, glue and acetone soln are become liquid according to certain proportions, then waters and pour insulated type jacket surface at the 3rd section, the specification of the disclosure file.Technique disclosed in it also belongs to wet coating method graphite spraying.

The patent No. is that the utility model patent of ZL922156964 discloses a kind of high conducting coated cable, this cable cover(ing) external surface coating is made up of non-metallic conducting material, organic bond and organic solvent, concrete non-metallic conducting material is made up of graphite and carbon black, and organic solvent can be acetone.As can be seen here, jacket outer surface coating also applies through wet coating method.

All there is a common feature in the technique of several wet coating method graphite spraying of above-mentioned introduction, namely in graphite solution all containing organic bond, organic solvent.The existence of organic bond, organic solvent not only increases production cost, and such as organic solvent-acetone solution has corrosivity to rubber in process of production, volatile, inflammable, has danger during operation, is unfavorable for that operating personnel's is healthy.But adopt identical technique, if without the existence of organic bond, organic solvent, equadag coating and pe sheath are deposited with power each other and decline, and do not reach processing quality requirement.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of sheath of hv cable outer semiconducting layer wet coating process method, and this technique is simple, the low and handling safety of cost, harmless.

In order to solve above-mentioned technical problem, technical scheme of the present invention is: a kind of sheath of hv cable outer semiconducting layer wet coating process method, and it comprises the following steps:

1) prepare graphite solution, mixed by graphite powder with water, wherein the mass percent of water and graphite is 1.5-2:1.The present invention breaks through traditional wet coating technique, graphite powder and water is only comprised in graphite solution, abandon traditional organic bond and the use of organic solvent, object be with in graphite solution, add organic bond, organic solvent is the same obtains same adhesive force effect.

2) at 15-30 DEG C, adopt air pressure pump, by pipeline, above-mentioned solution is watered pouring on cable cover(ing) surface, the pressure watering pouring is 0.18-0.28MPa.This step is core of the present invention, is and in graphite solution, adds organic bond, the same basic place obtaining same adhesive force effect of organic solvent.

Present invention process strictly controls the temperature of graphite solution toward cable cover(ing) surface spraying, and have the existence of organic bond at graphite solution under, temperature is too low or the too high impact on adhesive force is little.But not containing organic bond in graphite solution of the present invention, when temperature is too low, will adhesive force be had a strong impact on.Research shows, at 50-60 DEG C, is conducive to curing of coatings film forming most, takes second place at 65-80 DEG C, therefore will be unfavorable for follow-uply being smeared evenly by graphite after temperature reaches said temperature interval.Amid all these factors, the present invention selects to be watered by graphite solution at 15-30 DEG C and drenches on cable cover(ing) surface.

Another innovative point of present invention process is the pressure watering pouring, and the operation principle below in conjunction with rubber is described.During writing with erasing rubber pencil, be that rubber is walked the writing be made up of pencil powder (carbonaceous powder) from paper absorption in fact.As long as wipe with rubber one, " footprint " pencil writing along rubber just disappears, and namely rubber is to the absorption affinity of pencil powder, is greater than the absorption affinity of paper to pencil powder.And time with pen writing, rubber is then difficult to writing to wipe, reason is that now to wipe be that the surface of paper and any writing (entering the ink in paper) of inside of paper dark are a little wiped.The pressure that the present invention waters pouring is the reverse thinking of this principle, enough large and under being unlikely to make graphite solution reflect the pressure spilt, make the graphite in graphite solution " embedding " on cable cover(ing) surface, enhancing adhesive force.

3) by sponge polished die, graphite solution is smeared evenly.

4) in sponge polished die exit, compressed air drier is utilized to be dried up by cable surface.

Described sponge polished die is two groups, and two groups of sponge polished die Main Functions ensure that graphite smears the uniform moisture simultaneously can removing graphite solution.Like this, after the process of sponge polished die, cable cover(ing) surface moisture is seldom residual, ensures that in subsequent handling, cable surface liquid is easily dried, and can not cause cable surface to have current vestige.

The invention has the beneficial effects as follows:

1. when not using organic bond, organic solvent, ensure that graphite adhesive force, difficult drop-off, having saved production cost, easy and simple to handle; Suitable with the adhesive force using organic bond, organic solvent to obtain in graphite solution.

2. coated with graphite is even, and outward appearance is better.

3. wet coating compares saving graphite, reduces environmental pollution, is conducive to the health of operating personnel.

4., after coated with graphite, lettering is very clear, easily recognizes.

Embodiment

Embodiment 1

Water and graphite prepare graphite solution according to mass percent 1.5:1, are mixed by graphite powder with water, and at 30 DEG C, adopt air pressure pump, by pipeline, above-mentioned solution is watered pouring on cable cover(ing) surface, the pressure watering pouring is 0.25MPa.Graphite is smeared evenly fully by two groups of sponge polished dies, to greatest extent cable cover(ing) surface moisture is removed, finally in sponge polished die exit, utilize compressed air drier to be dried up by cable surface.

Embodiment 2

Water and graphite prepare graphite solution according to mass percent 2:1, are mixed by graphite powder with water, and at 25 DEG C, adopt air pressure pump, by pipeline, above-mentioned solution is watered pouring on cable cover(ing) surface, the pressure watering pouring is 0.18MPa.Graphite is smeared evenly fully by two groups of sponge polished dies, to greatest extent cable cover(ing) surface moisture is removed, finally in sponge polished die exit, utilize compressed air drier to be dried up by cable surface.

Embodiment 3

Water and graphite prepare graphite solution according to mass percent 1.5:1, are mixed by graphite powder with water, and at 15 DEG C, adopt air pressure pump, by pipeline, above-mentioned solution is watered pouring on cable cover(ing) surface, the pressure watering pouring is 0.28MPa.Graphite is smeared evenly fully by two groups of sponge polished dies, to greatest extent cable cover(ing) surface moisture is removed, finally in sponge polished die exit, utilize compressed air drier to be dried up by cable surface.

The graphite solution of conventional wet coating method generally accounts for 8-10% containing graphite, and acetone accounts for more than 80%, sometimes in order to improve the tack of graphite, can add the quick-drying polyester ammonia varnish of about about 0.4% in the solution.This kind of solution utilizes the electrically conductive graphite coating adhesion (as a comparison case) of conventional technique acquisition to contrast as following table with the adhesive force of the electrically conductive graphite coating of the embodiment of the present invention 1,2,3:

	Embodiment 1	Embodiment 2	Embodiment 3	Comparative example
					Adhesive force (level)	1	1	1	1
Detection method	GB/T 9286-88	GB/T 9286-88	GB/T 9286-88	GB/T 9286-88

As seen from the above table, the adhesive force that obtains of adhesive force and the conventional wet coating method (containing organic bond, organic solvent in graphite solution) of electrically conductive graphite coating of the present invention is suitable.

Above-described embodiment does not limit the present invention in any way, and the technical scheme that the mode that every employing is equal to replacement or equivalent transformation obtains all drops in protection scope of the present invention.

Claims (2)

1. a sheath of hv cable outer semiconducting layer wet coating process method, is characterized in that comprising the following steps:

1) prepare graphite solution, mixed by graphite powder with water, wherein the mass percent of water and graphite is 1.5-2:1;

2) at 15-30 DEG C, adopt air pressure pump, by pipeline, above-mentioned solution is watered pouring on cable cover(ing) surface, the pressure watering pouring is 0.18-0.28MPa;

3) by sponge polished die, graphite solution is smeared evenly;

4) in sponge polished die exit, compressed air drier is utilized to be dried up by cable surface.

2. sheath of hv cable outer semiconducting layer wet coating process method according to claim 1, is characterized in that: described sponge polished die is two groups.