Waterproof cable for submersible pump

Abstract

The invention relates to the technical field of cables, and provides a waterproof cable for a submersible pump, the waterproof cable comprises a conductor, an insulating layer and a sheath layer which are sequentially arranged from inside to outside, and the sheath layer comprises the following raw materials in parts by weight: 50-60 parts of ethylene propylene diene monomer, 10-15 parts of bentonite, 1-3 parts of an antioxidant, 2-4 parts of a plasticizer and 0.5-1.5 parts of a cross-linking agent; the bentonite is composed of sodium bentonite and lithium bentonite, and the mass ratio of the sodium bentonite to the lithium bentonite is (1-5): 1. According to the technical scheme, the problems of poor waterproof performance and poor corrosion resistance of the waterproof cable for the submersible pump in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to a waterproof cable for a submersible pump. Background Art

[0002] Waterproof cable is a cable with special protective properties. It can prevent moisture from entering the cable, thereby ensuring that the cable can still work normally in a humid environment or when in direct contact with water. It is widely used in water conservancy projects, construction facilities and other fields.

[0003] Although existing waterproof cables are designed with a variety of waterproof measures, waterproof failure may still occur during long-term use, especially in complex underwater environments. For example, waterproof cables for submersible pumps, once short-circuited due to water ingress, will not only damage the equipment, but may also cause serious accidents such as gas explosions, threatening the lives of underground personnel. In addition, the environment in which submersible pumps are used is usually complex, and the water may contain various chemicals, such as salt, acid, alkali, etc. The cable is easily corroded and poses a safety hazard. Therefore, it is very necessary to develop a highly waterproof and corrosion-resistant waterproof cable for submersible pumps. Summary of the invention

[0004] The invention provides a waterproof cable for a submersible pump, which solves the problem of poor waterproof performance and poor corrosion resistance of the waterproof cable for a submersible pump in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides a waterproof cable for a submersible pump, comprising a conductor, an insulating layer and a sheath layer arranged in sequence from the inside to the outside, wherein the sheath layer comprises the following component raw materials in parts by weight: 50-60 parts of EPDM rubber, 10-15 parts of bentonite, 1-3 parts of an antioxidant, 2-4 parts of a plasticizer, and 0.5-1.5 parts of a cross-linking agent; The bentonite is composed of sodium bentonite and lithium bentonite, and the mass ratio of the sodium bentonite to the lithium bentonite is 1-5:1.

[0006] As a further technical solution, the conductor is made of copper.

[0007] As a further technical solution, the material of the insulating layer is EPDM rubber.

[0008] As a further technical solution, the mass ratio of the sodium-based bentonite to the lithium-based bentonite is 2-3:1.

[0009] As a further technical solution, the raw material also includes polystyrene, and the mass ratio of the EPDM rubber to the polystyrene is 5:1-2.

[0010] In the present invention, polystyrene is added as a raw material to prepare the sheath layer. The interaction between polystyrene and the EPDM rubber matrix can reduce the pores and water penetration channels inside the sheath layer, further improving the waterproof performance and corrosion resistance of the waterproof cable.

[0011] As a further technical solution, when the bentonite is modified bentonite, the modified bentonite is obtained by treating bentonite with a modifier, and the modifier is a thiophenesulfonic acid compound.

[0012] In the present invention, a thiophenesulfonic acid compound is used as a modifier to modify bentonite to obtain modified bentonite. The modified bentonite can not only capture and absorb the infiltrated water molecules and reduce the free diffusion of water in the sheath layer, but also fix the corrosive ions and reduce the corrosive effect of the corrosive ions on the sheath layer material, thereby further improving the waterproof performance and corrosion resistance of the waterproof cable.

[0013] As a further technical solution, the thiophene sulfonic acid compound includes one or more of thiophene-2-sulfonic acid, 3-methyl-thiophene-2-sulfonic acid, and 5-methyl-thiophene-2-sulfonic acid.

[0014] As a further technical solution, in the raw material of the modified bentonite, the mass ratio of the modifier to the bentonite is 1-2:15.

[0015] As a further technical solution, the preparation method of the modified bentonite comprises the following steps: dispersing the modifier in a solvent, adding bentonite, centrifuging and drying after modification to obtain the modified bentonite.

[0016] As a further technical solution, the modification temperature is 70° C. and the modification time is 6 hours.

[0017] As a further technical solution, the mass ratio of the bentonite to the solvent is 1:10.

[0018] As a further technical solution, at least one of the following technical features is also included: The antioxidant includes one or more of antioxidant 405, antioxidant 1010, and antioxidant 626; The plasticizer includes one or more of dibutyl sebacate, dioctyl azelate, and triphenyl phosphate; The cross-linking agent includes one or more of dicumyl peroxide, di-tert-butyl peroxide, and benzoyl peroxide.

[0019] The present invention also provides a method for preparing a waterproof cable for a submersible pump, comprising the following steps: S1, covering the insulating layer on the outside of the conductor to obtain a semi-finished cable; S2. Mix the raw materials of the sheath layer evenly, extrude them, and coat them on the cable semi-finished product to obtain the cable.

[0020] As a further technical solution, the extrusion temperature is 160-180°C.

[0021] The working principle and beneficial effects of the present invention are: In the present invention, EPDM rubber is used as a raw material, and sodium bentonite and lithium bentonite are added to prepare a cable sheath layer. By coordinating the mass ratio of the two materials and exerting the synergistic effect of the two materials, the bentonite absorbs water and expands to fill the tiny gaps and crevices of the cable sheath layer, thereby enhancing the stability and integrity of the waterproof structure of the sheath layer. By exerting the ion exchange characteristics and adsorption effect of the bentonite and the corrosive medium, further erosion of the corrosive substances is prevented, thereby improving the waterproof performance and corrosion resistance of the waterproof cable. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the following examples and comparative examples: Conductor: Material is copper; Insulation layer: the material is EPDM rubber; EPDM rubber: model 4725P; Polystyrene: Model: HIPS-622P; Sodium bentonite: particle size 325 mesh, manufactured by Tongchuang Bentonite Factory in Xinyang Industrial City; Lithium-based bentonite: particle size 325 mesh, manufacturer is Heishan County Everbright Bentonite Co., Ltd.

[0024] Example 1 A method for preparing a waterproof cable for a submersible pump comprises the following steps: S1. Wrapping the insulating layer on the conductor to obtain a semi-finished cable; S2. Weigh 50 parts of EPDM rubber, 10 parts of bentonite, 1 part of antioxidant 405, 2 parts of dibutyl sebacate, and 0.5 parts of dicumyl peroxide, mix them evenly, extrude them at 160°C, and coat the semi-finished cable to obtain a cable; wherein the bentonite is composed of sodium bentonite and lithium bentonite in a mass ratio of 1:1.

[0025] Example 2 A method for preparing a waterproof cable for a submersible pump comprises the following steps: S1. Wrapping the insulating layer on the conductor to obtain a semi-finished cable; S2. Weigh 55 parts of EPDM rubber, 12 parts of bentonite, 2 parts of antioxidant 1010, 3 parts of dioctyl azelaic acid, and 1 part of di-tert-butyl peroxide, mix them evenly, extrude them at 170°C, and coat the semi-finished cable to obtain a cable; wherein the bentonite is composed of sodium bentonite and lithium bentonite in a mass ratio of 2:1.

[0026] Example 3 A method for preparing a waterproof cable for a submersible pump comprises the following steps: S1. Wrapping the insulating layer on the conductor to obtain a semi-finished cable; S2. Weigh 60 parts of EPDM rubber, 15 parts of bentonite, 3 parts of antioxidant 626, 4 parts of triphenyl phosphate, and 1.5 parts of benzoyl peroxide, mix well, extrude at 180° C., and coat the semi-finished cable to obtain a cable; wherein the bentonite is composed of sodium bentonite and lithium bentonite in a mass ratio of 5:1.

[0027] Example 4 Compared with Example 1, the difference of Example 4 is that the bentonite consists of sodium-based bentonite and lithium-based bentonite in a mass ratio of 3:1.

[0028] Example 5 A method for preparing a waterproof cable for a submersible pump comprises the following steps: S1. Wrapping the insulating layer on the conductor to obtain a semi-finished cable; S2. Weigh 50 parts of EPDM rubber, 10 parts of bentonite, 1 part of antioxidant 405, 2 parts of dibutyl sebacate, 0.5 parts of dicumyl peroxide, and 10 parts of polystyrene, mix well, extrude at 160°C, and coat the semi-finished cable to obtain a cable; wherein the bentonite is composed of sodium bentonite and lithium bentonite in a mass ratio of 3:1.

[0029] Example 6 Compared with Example 5, the difference in Example 6 is that the amount of polystyrene added is 20 parts.

[0030] Example 7 The preparation method of modified bentonite comprises the following steps: weighing 1 part of thiophene-2-sulfonic acid, adding it to 150 parts of water, adding 15 parts of bentonite, heating to 70°C for reaction for 6 hours, centrifuging and drying to obtain modified bentonite, wherein the bentonite is composed of sodium bentonite and lithium bentonite in a mass ratio of 3:1; Compared with Example 6, the difference of Example 7 is that the bentonite is replaced by an equal amount of modified bentonite obtained by the above preparation method.

[0031] Example 8 Compared with Example 7, the difference in Example 8 is that the added amount of thiophene-2-sulfonic acid is 2 parts.

[0032] Example 9 Compared with Example 8, Example 9 is different in that thiophene-2-sulfonic acid is replaced by an equal amount of 3-methyl-thiophene-2-sulfonic acid.

[0033] Example 10 Compared with Example 5, the difference in Example 10 is that the amount of polystyrene added is 15 parts.

[0034] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is that the bentonite is sodium-based bentonite.

[0035] Comparative Example 2 Compared with Example 1, the difference in Comparative Example 2 is that the bentonite is lithium-based bentonite.

[0036] The waterproof cables prepared in Examples 1 to 10 and Comparative Examples 1 to 2 were tested according to the following method: Sample preparation: Cut the cable sheath along the cable axis, take a narrow strip, remove all cable components in the narrow strip, and obtain the sample to be tested.

[0037] 1. Water absorption test: According to the water absorption test method specified in GB / T 2951.13-2008 "General test methods for insulation and sheath materials of electric and optical cables Part 13: General test methods - Density determination method - Water absorption test - Shrinkage test", the sample is first pretreated under the following pretreatment conditions: vacuum drying oven at 70℃ for 72h, and then the waterproof performance of the sample is tested under the test conditions of 60℃ for 20d.

[0038] 2. Corrosion resistance: First immerse the sample in a 10wt% hydrochloric acid solution for 168h, and then immerse the sample in a 10wt% sodium hydroxide solution for 168h, at a temperature of 23℃ and standard atmospheric pressure. According to the test method for elongation at break specified in GB / T 2951.11-2008 "General test methods for insulation and sheath materials of electric and optical cables Part 11: General test methods - Thickness and dimensional measurement - Mechanical properties test", the corrosion resistance of the samples before and after immersion treatment was tested, and the change rate of elongation at break was calculated, which is [(elongation at break after immersion - elongation at break before immersion) / elongation at break before immersion] × 100%.

[0039] The test results are shown in the following table: Table 1 Performance test results of waterproof cables prepared in Examples 1 to 10 and Comparative Examples 1 to 2

[0040] Compared with Comparative Examples 1 and 2, Example 1 adds sodium bentonite and lithium bentonite at the same time. As a result, the absolute values ​​of the water absorption and the change rate of elongation at break of Example 1 are smaller than those of Comparative Examples 1 and 2, indicating that sodium bentonite and lithium bentonite play a synergistic role and can improve the waterproof performance and corrosion resistance of the waterproof cable.

[0041] Compared with Example 1, polystyrene is added in Examples 5, 6 and 10. As a result, the absolute values ​​of the water absorption and the change rate of elongation at break of Examples 5, 6 and 10 are all smaller than those of Example 1, indicating that the addition of polystyrene can improve the waterproof performance and corrosion resistance of the waterproof cable.

[0042] Compared with Example 6, Examples 7 to 9 add modified bentonite modified with a thiophenesulfonic acid compound. As a result, the absolute values ​​of the water absorption and the change rate of elongation at break of Examples 7 to 9 are smaller than those of Example 6, indicating that after the bentonite is modified with a thiophenesulfonic acid compound, the waterproof performance and corrosion resistance of the waterproof cable obtained are better.

[0043] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A waterproof cable for a submersible pump, characterized in that: It comprises a conductor, an insulating layer and a sheath layer arranged in sequence from the inside to the outside, wherein the sheath layer comprises the following component raw materials in parts by weight: 50-60 parts of EPDM rubber, 10-15 parts of bentonite, 1-3 parts of antioxidant, 2-4 parts of plasticizer, and 0.5-1.5 parts of cross-linking agent; The bentonite is composed of sodium bentonite and lithium bentonite, and the mass ratio of the sodium bentonite to the lithium bentonite is 1-5:

1.

2. A waterproof cable for a submersible pump according to claim 1, characterized in that: The material of the conductor is copper.

3. A waterproof cable for a submersible pump according to claim 1, characterized in that: The material of the insulating layer is EPDM rubber.

4. A waterproof cable for a submersible pump according to claim 1, characterized in that: The mass ratio of the sodium bentonite to the lithium bentonite is 2-3:

1.

5. A waterproof cable for a submersible pump according to claim 1, characterized in that: The raw materials also include polystyrene, and the mass ratio of the EPDM rubber to the polystyrene is 5:1-2.

6. A waterproof cable for a submersible pump according to claim 1, characterized in that: When the bentonite is modified bentonite, the modified bentonite is obtained by modifying bentonite with a modifier, and the modifier is a thiophenesulfonic acid compound.

7. A waterproof cable for a submersible pump according to claim 6, characterized in that: The thiophenesulfonic acid compound includes one or more of thiophene-2-sulfonic acid, 3-methyl-thiophene-2-sulfonic acid, and 5-methyl-thiophene-2-sulfonic acid.

8. A waterproof cable for a submersible pump according to claim 6, characterized in that: In the raw material of the modified bentonite, the mass ratio of the modifier to the bentonite is 1-2:

15.

9. A waterproof cable for a submersible pump according to claim 6, characterized in that: The preparation method of the modified bentonite comprises the following steps: dispersing a modifier in a solvent, adding bentonite, and centrifuging and drying after modification to obtain the modified bentonite.

10. A waterproof cable for a submersible pump according to claim 1, characterized in that: Also includes at least one of the following technical features: The antioxidant includes one or more of antioxidant 405, antioxidant 1010, and antioxidant 626; The plasticizer includes one or more of dibutyl sebacate, dioctyl azelate, and triphenyl phosphate; The cross-linking agent includes one or more of dicumyl peroxide, di-tert-butyl peroxide, and benzoyl peroxide.

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