阅读说明：本技术 一种直流支撑电容器的真空浇注工艺 (Vacuum pouring process of direct-current support capacitor ) 是由 孙晓武 李印达 于 2021-07-08 设计创作，主要内容包括：本发明公开了一种直流支撑电容器的真空浇注工艺,包括以下工序：电容器处理、树脂配置、树脂取样、第一次浇注、第二次浇注、浇注检查、树脂固化；规定了各工序有关的的温度、时间和真空剩余气压。本发明的工艺方法适用不锈钢(或铝)外壳电容器的结构、特性要求,可有效地解决浇注的电容器内气泡多、绝缘性能差的问题,提高产品的绝缘性能和局部放电水平,提高产品的生产效率。(The invention discloses a vacuum casting process of a direct current support capacitor, which comprises the following steps: capacitor treatment, resin preparation, resin sampling, first pouring, second pouring, pouring inspection and resin curing; the temperature, time and vacuum residual pressure related to each process are specified. The technological method of the invention is suitable for the structure and characteristic requirements of the stainless steel (or aluminum) shell capacitor, can effectively solve the problems of more bubbles and poor insulating property in the cast capacitor, improves the insulating property and partial discharge level of the product, and improves the production efficiency of the product.)

1. A vacuum casting process of a direct current support capacitor, comprising the following steps:

(1) capacitor treatment: assembling a capacitor to be cast into a tool fixture, wherein a casting opening and an air outlet of the capacitor are respectively in threaded connection with a casting device and an air outlet pipe, then putting the capacitor into a first constant-temperature drying box and heating to 80 ℃, keeping the temperature for 1-2 hours, putting the capacitor into a vacuum tank for vacuum treatment, keeping the vacuum degree at-0.1 MPa for 15 minutes, closing a vacuum pipeline valve of the vacuum tank, keeping the vacuum in the vacuum tank to be cast, and keeping the vacuum in the vacuum tank;

(2) resin preparation: putting the A-type raw material which is opened and packaged into a second constant-temperature drying box, heating the whole body of the A-type raw material to 40 +/-10 ℃, continuing for 10-30 minutes at the temperature, sucking the A-type raw material into an A material barrel of a glue pouring machine, sucking/pouring a B-type raw material into a B material barrel, starting a stirring system of the glue pouring machine, continuously stirring the raw material, starting a vacuum pump of the glue pouring machine to carry out vacuum treatment on the raw material in the A, B material barrel, keeping the vacuum degree for at least 30 minutes when the vacuum degree reaches-0.1 MPa, closing the vacuum pump of the glue pouring machine, keeping the material barrel in vacuum, and waiting for pouring;

(3) sampling resin: opening a blank breaking valve of the glue-pouring machine, wherein the pressure in a charging basket is normal atmospheric pressure, starting a discharging system of the glue-pouring machine, independently sampling A, B type raw materials for 5 seconds in a continuous discharging mode, weighing and comparing A, B type raw materials to meet the proportion, and reserving and taking mixed samples and reserving remark information;

(4) first pouring: moving a glue outlet pipe of a glue pouring machine into a pouring appliance of a capacitor, adjusting the vacuum degree in a vacuum tank of the capacitor to keep the vacuum degree at-0.08 MPa, starting a pouring system of the glue pouring machine, injecting resin into the capacitor after the resin sequentially passes through the glue outlet pipe and the pouring appliance, injecting the resin for 15-30 minutes according to different types of capacitors, observing that the resin of an air outlet pipe is at a 3mm scale mark, completing the first pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening a vacuum breaking valve, and performing vacuum breaking treatment on the vacuum tank;

(5) and (3) secondary pouring: after the vacuum tank is broken for 5-10 minutes, unscrewing the air outlet pipe, checking the descending degree of the liquid level of resin poured by the capacitor, reinstalling the air outlet pipe, starting the pouring system of the glue pouring machine again, performing appropriate amount of supplementary pouring, observing that the resin of the air outlet pipe is on a scale mark of 3mm, finishing the second pouring of the capacitor, continuously keeping the vacuum inside the vacuum tank for about 2 minutes, opening the breaking valve, performing vacuum tank breaking treatment, unscrewing a pouring appliance, and moving the capacitor to a specified position outside the vacuum tank;

(6) pouring inspection: the excess resin in the air outlet pipe is extracted, no residual casting stain is left on the surface of the capacitor, the casting surface is smooth, no bubble holes or other adverse conditions exist, no dust particles exist, and no empty belly phenomenon exists in the capacitor;

(7) curing the resin: curing the resin-poured capacitor at normal temperature for at least 48 hours, and then removing the tool clamp;

wherein, the deviation of the above time can be within + -5%, and the deviation of the temperature can be within + -5%.

2. The vacuum casting process of a dc support capacitor of claim 1, wherein: the resin is any suitable epoxy or polyurethane.

Technical Field

The invention relates to the field of capacitor manufacturing, in particular to a vacuum casting process of a direct-current support capacitor.

Background

The direct current support capacitor is a key device of the converter, and plays roles in stabilizing voltage, filtering and the like on a direct current side in the converter. At present, high-power converters such as high-voltage frequency converters of dozens of megawatts, high-speed motor car converters, high-power STATCOM, direct-current capacitors for flexible direct-current transmission engineering and the like need to use high-voltage large-capacity direct-current supporting capacitors.

These dc support capacitors are metallized polypropylene film capacitors. In addition, such capacitors are also increasingly constructed with dry, stainless steel (or aluminum) housings and the ever decreasing size, the operating field strength of metallized polypropylene films is increasing. The common characteristics of the capacitor are high voltage, large capacity and heavy weight, the weight range of the direct current support capacitor is 100-210 kg, and the weight of the cast resin is 20-50 kg. Thus, the method of casting the resin is also a more important process.

Document CN107316743B discloses a casting process of a dry power electronic capacitor, which includes the following steps: preparing a mould, placing a core, drying the core, degassing resin, mixing the resin, pouring the resin, curing the resin, demoulding and inspecting; the temperature, time and vacuum residual pressure related to each process are specified. The method is suitable for producing dry capacitor without metal shell. Therefore, this method is not suitable for resin casting of dc support capacitors of stainless steel (or aluminum) housing construction.

Document CN112403813A discloses a vacuum glue injection device and a glue injection method for a capacitor, in which an insulating glue is injected into the capacitor by using a pressure difference (ρ gh). The important points of the method are that: when designing the capacitor shell, the height of the capacitor shell is not more than 1/2S 10³Where S is the wall thickness of the housing in millimeters. Otherwise there is a possibility that the capacitor case will collapse. Thus, the method is also limited to the application of capacitor glue injection within a specific height range. In addition, the method has the condition of long glue injection time, so that the production efficiency is greatly reduced.

The method for pouring the resin is applied to the field of manufacturing of the direct-current support capacitor for a short time. In addition, due to the special structure of the capacitor, the pouring process of other electrical products often causes the instability of the capacitor quality, the phenomena of more bubbles, poor insulating property and the like occur, the defects of poor appearance, low partial discharge level and the like of the poured capacitor are caused, waste products are formed, and economic loss is brought to a manufacturing factory.

Disclosure of Invention

In order to solve the problems and improve the vacuum casting quality of resin, the invention provides a vacuum casting process of a direct current support capacitor (hereinafter referred to as a capacitor).

The technical scheme adopted by the invention is as follows.

The vacuum casting process of the capacitor comprises the following steps:

(1) capacitor treatment: and (3) assembling a capacitor to be cast into a tool fixture, wherein a casting opening and an air outlet of the capacitor are respectively in threaded connection with a casting device and an air outlet pipe, then putting the capacitor into a first constant-temperature drying box and heating to 80 ℃, keeping the temperature for 1-2 hours, putting the capacitor into a vacuum tank for vacuum treatment, keeping the vacuum degree at-0.1 MPa for 15 minutes, closing a vacuum pipeline valve of the vacuum tank, keeping the vacuum in the vacuum tank, and waiting for casting.

(2) Resin preparation: putting the A-type raw material which is opened and packaged into a second constant-temperature drying box, heating the whole body of the A-type raw material to 40 +/-10 ℃, continuing for 10-30 minutes at the temperature, sucking the A-type raw material into an A material barrel of a glue pouring machine, sucking/pouring a B-type raw material into a B material barrel, starting a stirring system of the glue pouring machine, continuously stirring the raw material, starting a vacuum pump of the glue pouring machine to carry out vacuum treatment on the raw material in the A, B material barrel, keeping the vacuum degree for at least 30 minutes when the vacuum degree reaches-0.1 MPa, closing the vacuum pump of the glue pouring machine, keeping the material barrel in vacuum, and waiting for pouring.

(3) Sampling resin: open the rubber-filling machine broken air valve, the storage bucket internal pressure is normal atmospheric pressure, opens rubber-filling machine discharge system, adopts the continuous discharging mode, and A, B type raw materials of independent sample each 5 seconds, weigh the comparison to A, B type raw materials again, satisfy the proportion, leave and get the sample after mixing and remain, remark information.

(4) First pouring: moving a glue outlet pipe of a glue pouring machine into a pouring appliance of a capacitor, adjusting the vacuum degree in a vacuum tank of the capacitor to keep the vacuum degree at-0.08 MPa, starting a pouring system of the glue pouring machine, injecting resin into the capacitor after the resin sequentially passes through the glue outlet pipe and the pouring appliance, injecting the resin for 15-30 minutes according to different types of capacitors, observing that the resin of an air outlet pipe is at a 3mm scale mark, completing the first pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening a vacuum breaking valve, and performing vacuum breaking treatment on the vacuum tank.

(5) And (3) secondary pouring, namely after the vacuum tank is broken to be empty for 5-10 minutes, unscrewing the air outlet pipe, checking the descending degree of the liquid level of the resin poured by the capacitor, reinstalling the air outlet pipe, starting the pouring system of the glue pouring machine again, performing appropriate amount of supplementary pouring, finishing the secondary pouring of the capacitor when the resin of the air outlet pipe is observed to be on a scale mark of 3mm, continuously keeping the vacuum inside the vacuum tank for about 2 minutes, opening the breaking valve, performing vacuum tank breaking treatment, unscrewing a pouring appliance, and moving the capacitor to a specified position outside the vacuum tank.

(6) Pouring inspection: and (3) extracting the redundant resin in the air outlet pipe, wherein the surface of the capacitor has no residual casting stain, the casting surface is smooth, has no bubble holes or other adverse conditions and has no dust particles, and the interior of the capacitor has no hollow phenomenon.

(7) Curing the resin: and (3) curing the resin-poured capacitor at normal temperature for at least 48 hours, and then removing the tool clamp.

Wherein, the deviation of the above time can be within + -5%, and the deviation of the temperature can be within + -5%.

The resin is any suitable epoxy resin or polyurethane, and the A, B material mixing ratio meets the requirements of a resin supplier.

Further, the type A starting material was heated to 40. + -. 10 ℃ throughout to evaporate excess water while also diluting its viscosity.

Further, when the air-break valve is opened, the speed is slow, so that the resin in the capacitor is prevented from being splashed out due to gas impact.

Furthermore, the casting device is conical, and the material is stainless steel.

Furthermore, the air outlet pipe is a transparent PVC pipe.

Further, the time of each process operation can be adjusted according to the size of the capacitor.

Further, the normal-temperature curing time of the capacitor is 48 hours, so that the resin can be completely cured, and the delamination of the joint of the resin and the shell can be avoided.

The invention has the beneficial effects that: according to the requirements of the structure and the characteristics of the stainless steel (or aluminum) shell capacitor, the method can effectively solve the problems of more bubbles and poor insulating property in the cast capacitor, improve the insulating property and the partial discharge level of the product and improve the production efficiency of the product.

Detailed Description

The following specific examples further illustrate the invention.

The vacuum casting process of the capacitor comprises the following steps:

(1) capacitor treatment: assembling a capacitor to be cast into a tool fixture, wherein a casting opening and an air outlet of the capacitor are respectively in threaded connection with a casting device and an air outlet pipe, then putting the capacitor into a first constant-temperature drying box and heating to 80 ℃, keeping the temperature for 1-2 hours, putting the capacitor into a vacuum tank for vacuum treatment, keeping the vacuum degree at-0.1 MPa for 15 minutes, closing a vacuum pipeline valve of the vacuum tank, keeping the vacuum in the vacuum tank to be cast, and keeping the vacuum in the vacuum tank;

for example, if the capacitor size is 320mm long, 175mm wide, 400 mm high, the capacitor processing sequence may be: assembling a capacitor to be cast into a tool fixture, wherein a casting opening and an air outlet of the capacitor are respectively in threaded connection with a casting device and an air outlet pipe, then putting the capacitor into a first constant-temperature drying box and heating to 80 ℃, keeping the temperature for 1 hour, putting the capacitor into a vacuum tank for vacuum treatment, keeping the vacuum degree at-0.1 MPa for 15 minutes, closing a vacuum pipeline valve of the vacuum tank, keeping the vacuum in the vacuum tank to be cast, and waiting for casting;

alternatively, if the capacitor is 320mm long, 175mm wide and 800 mm high, the capacitor processing steps may be: and (3) assembling a capacitor to be cast into a tool fixture, wherein a casting opening and an air outlet of the capacitor are respectively in threaded connection with a casting device and an air outlet pipe, then putting the capacitor into a first constant-temperature drying box and heating to 80 ℃, keeping the temperature for 2 hours, putting the capacitor into a vacuum tank for vacuum treatment, keeping the vacuum degree at-0.1 MPa for 15 minutes, closing a vacuum pipeline valve of the vacuum tank, keeping the vacuum in the vacuum tank, and waiting for casting.

(2) Resin preparation: putting the A-type raw material which is opened and packaged into a second constant-temperature drying box, heating the whole body of the A-type raw material to 40 +/-10 ℃, continuing for 10-30 minutes at the temperature, sucking the A-type raw material into an A material barrel of a glue pouring machine, sucking/pouring a B-type raw material into a B material barrel, starting a stirring system of the glue pouring machine, continuously stirring the raw material, starting a vacuum pump of the glue pouring machine to carry out vacuum treatment on the raw material in the A, B material barrel, keeping the vacuum degree for at least 30 minutes when the vacuum degree reaches-0.1 MPa, closing the vacuum pump of the glue pouring machine, keeping the material barrel in vacuum, and waiting for pouring;

for example, if the production month is 6 to 10 months per year and the ambient temperature is high, the resin preparation process may be: putting the A-type raw material which is opened and packaged into a second constant-temperature drying box, heating the whole body of the A-type raw material to 40 +/-10 ℃, continuing for 10 minutes at the temperature, sucking the A-type raw material into an A material barrel of a glue pouring machine, sucking/pouring a B-type raw material into a B material barrel, starting a stirring system of the glue pouring machine, continuously stirring the raw material, starting a vacuum pump of the glue pouring machine to carry out vacuum treatment on the raw material in the A, B material barrel, keeping the vacuum degree for at least 30 minutes when the vacuum degree reaches-0.1 MPa, closing the vacuum pump of the glue pouring machine to keep the material barrel in vacuum, and waiting for pouring;

or, if the production time is 12-2 months per year and the environmental temperature is low, the resin preparation process may be: putting the A-type raw material which is opened and packaged into a second constant-temperature drying box, heating the whole body of the A-type raw material to 40 +/-10 ℃, continuing for 30 minutes at the temperature, sucking the A-type raw material into an A material barrel of a glue pouring machine, sucking/pouring a B-type raw material into a B material barrel, starting a stirring system of the glue pouring machine, continuously stirring the raw material, starting a vacuum pump of the glue pouring machine to carry out vacuum treatment on the raw material in the A, B material barrel, keeping the vacuum degree for at least 30 minutes when the vacuum degree reaches-0.1 MPa, closing the vacuum pump of the glue pouring machine, keeping the material barrel in vacuum, and waiting for pouring.

(3) Sampling resin: open the rubber-filling machine broken air valve, the storage bucket internal pressure is normal atmospheric pressure, opens rubber-filling machine discharge system, adopts the continuous discharging mode, and A, B type raw materials of independent sample each 5 seconds, weigh the comparison to A, B type raw materials again, satisfy the proportion, leave and get the sample after mixing and remain, remark information.

(4) First pouring: moving a glue outlet pipe of a glue pouring machine into a pouring appliance of a capacitor, adjusting the vacuum degree in a vacuum tank of the capacitor to keep the vacuum degree at-0.08 MPa, starting a pouring system of the glue pouring machine, injecting resin into the capacitor after the resin sequentially passes through the glue outlet pipe and the pouring appliance, injecting the resin for 15-30 minutes according to different types of capacitors, observing that the resin of an air outlet pipe is at a 3mm scale mark, completing the first pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening a vacuum breaking valve, and performing vacuum breaking treatment on the vacuum tank;

for example, if the capacitor size is 320mm long, 175mm wide and 400 mm high, the first casting process may be: moving a glue outlet pipe of a glue pouring machine into a pouring appliance of a capacitor, adjusting the vacuum degree in a vacuum tank of the capacitor to keep the vacuum degree at-0.08 MPa, starting a pouring system of the glue pouring machine, injecting resin into the capacitor after the resin sequentially passes through the glue outlet pipe and the pouring appliance, wherein the time for injecting the resin is 15 minutes, when observing that the resin of an air outlet pipe is at a 3mm scale mark, finishing the first pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening a vacuum breaking valve, and performing vacuum breaking treatment on the vacuum tank;

alternatively, if the capacitor is 320mm long, 175mm wide and 800 mm high, the second casting step may be: moving a glue outlet pipe of a glue pouring machine into a pouring appliance of a capacitor, adjusting the vacuum degree in a vacuum tank of the capacitor to keep the vacuum degree at-0.08 MPa, starting a pouring system of the glue pouring machine, injecting resin into the capacitor after the resin sequentially passes through the glue outlet pipe and the pouring appliance, wherein the time for injecting the resin is 30 minutes, when observing that the resin of an air outlet pipe is at a 3mm scale mark, finishing the first pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening a vacuum breaking valve, and performing vacuum breaking treatment on the vacuum tank.

(5) After the vacuum tank is broken to be empty for 5-10 minutes, unscrewing the air outlet pipe, checking the descending degree of the liquid level of the resin poured by the capacitor, reinstalling the air outlet pipe, starting the pouring system of the glue pouring machine again, performing appropriate amount of supplementary pouring, finishing the second pouring of the capacitor when observing that the resin of the air outlet pipe is on a 3mm scale mark, continuously keeping the vacuum inside the vacuum tank for about 2 minutes, opening the air breaking valve, performing vacuum tank breaking treatment, unscrewing a pouring appliance, and moving the capacitor to a specified position outside the vacuum tank;

for example, if the capacitor is 320mm long, 175mm wide and 400 mm high, the second casting step may be: after the vacuum tank is broken to be empty for 5 minutes, unscrewing an air outlet pipe, checking the liquid level descending degree of resin poured by the capacitor, reinstalling the air outlet pipe, starting a pouring system of the glue pouring machine again, performing appropriate amount of supplementary pouring, observing that the resin of the air outlet pipe is on a scale mark of 3mm, finishing the secondary pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening an air breaking valve, performing vacuum tank breaking treatment, unscrewing a pouring appliance, and moving the capacitor to a specified position outside the vacuum tank;

alternatively, if the capacitor is 320mm long, 175mm wide and 800 mm high, the second casting step may be: and after the vacuum tank is broken for 10 minutes, unscrewing the air outlet pipe, checking the descending degree of the liquid level of the resin poured by the capacitor, reinstalling the air outlet pipe, starting the pouring system of the glue pouring machine again, performing appropriate amount of supplementary pouring, observing that the resin of the air outlet pipe is on a scale mark of 3mm, finishing the second pouring of the capacitor, continuously keeping the vacuum in the vacuum tank for about 2 minutes, opening the breaking valve, performing vacuum tank breaking treatment, unscrewing the pouring appliance, and moving the capacitor to a specified position outside the vacuum tank.

(6) Pouring inspection: and (3) extracting the redundant resin in the air outlet pipe, wherein the surface of the capacitor has no residual casting stain, the casting surface is smooth, has no bubble holes or other adverse conditions and has no dust particles, and the interior of the capacitor has no hollow phenomenon.

(7) Curing the resin: and (3) curing the resin-poured capacitor at normal temperature for at least 48 hours, and then removing the tool clamp.

Wherein, the deviation of the above time can be within + -5%, and the deviation of the temperature can be within + -5%.

The resin is any suitable epoxy resin or polyurethane, and the A, B material mixing ratio meets the requirements of a resin supplier.

Further, the type A starting material was heated to 40. + -. 10 ℃ throughout to evaporate excess water while also diluting its viscosity.

Further, when the air-break valve is opened, the speed is slow, so that the resin in the capacitor is prevented from being splashed out due to gas impact.

Furthermore, the casting device is conical, and the material is stainless steel.

Furthermore, the air outlet pipe is a transparent PVC pipe.

Further, the time of each process operation can be adjusted according to the size of the capacitor.

Further, the normal-temperature curing time of the capacitor is 48 hours, so that the resin can be completely cured, and the delamination of the joint of the resin and the shell can be avoided.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.