CN100578897C - Explosion-proof vacuum pressure impregnated insulation device and its process method - Google Patents

Abstract

The invention relates to an explosion-proof vacuum pressure impregnation insulation device and its process method, which are suitable for impregnating insulating varnish on winding coils of high-voltage motors. Condenser, and a paint collecting tank is arranged at the bottom of the paint soaking tank, one end of the paint collecting tank communicates with the paint soaking tank, and the other end communicates with the paint delivery pipeline of the paint storage tank through the paint delivery and return valves. Using the device and its process method can not only effectively solve the remaining insulating varnish and solvent in the varnish tank, but also avoid the dilution of flammable and explosive styrene through the condenser when the vacuum unit evacuates the varnish tank. The agent is sucked into the vacuum unit and blocked by gelling, which has practical effects such as explosion-proof, safe and reliable, and saving raw materials.

Description

Explosion-proof vacuum pressure impregnated insulation device and its process method

technical field

The invention belongs to the technical field of pressure vessels, in particular to an explosion-proof vacuum pressure impregnated insulation device and a process method thereof for impregnating insulating varnishes for winding coils of high-voltage motors.

Background technique

The voltage generated by the generator can only be used through the grid transmission and sorting. Now, users combine the development needs of large drag and high power, and directly connect the motor to the transformer of 6Kv and above, which can reduce the loss of the line, and also reduce the re-investment of the low-voltage transformer and its auxiliary facilities. For this reason, high-voltage generators and electric motors of 6KV and above are popularized and applied in large areas. Since high-voltage motors are subject to high voltage and high current, in order to improve the withstand voltage level of high-voltage motor winding coils, vacuum pressure impregnation equipment is usually used to insulate the winding coils. During the insulation impregnation process, first start the vacuum unit to evacuate the varnish tank to remove the low molecular substances (such as water, styrene, xylene, etc.) inside the coil; then press the insulating varnish into the inside of the coil through high pressure , Improve the coil withstand voltage level. Although the current vacuum pressure impregnation equipment has good performance, it is impossible to avoid the influence of the insulating varnish remaining in the impregnation tank on the vacuum degree every time the vacuum is pumped, because the insulating varnish contains about 30% styrene or other diluents, and styrene or other diluents are flammable and explosive substances, the explosion limit range is 1-7%, and the spontaneous ignition point is 460 ° C. When there is more insulating varnish left in the varnish dipping tank, there will be more styrene or other diluents in the insulating varnish. When vacuuming, there will be more flammable and explosive gases entering the vacuum unit, especially benzene. Ethylene also has the characteristics of self-crosslinking and becoming a solid substance. The styrene or other diluents in the insulating varnish are pumped into the vacuum unit. Once solidified in the vacuum unit, it is easy to block the vacuum pump and cause the gas path to be blocked. And cause explosion accident, therefore there is great unsafe hidden danger. Vacuum pressure impregnation in the prior art does not fundamentally solve the residual insulating varnish and solvent in the impregnation tank, resulting in high dielectric loss in the winding coils of high-voltage motors after impregnation, which directly affects the service life of high-voltage motors.

Contents of the invention

The purpose of the present invention is to provide an explosion-proof vacuum pressure impregnation insulation device which can effectively avoid the suction of flammable and explosive gases by the vacuum unit, is safe and reliable, can reduce the residue of insulating varnish in the varnish immersion tank, and save raw materials.

Another object of the present invention is to provide a process method for explosion-proof vacuum pressure impregnation insulation.

The technical scheme adopted to realize the object of the present invention is: the device includes a paint soaking tank, a paint storage tank, and a vacuum unit, and a condenser connected with a refrigeration unit is added on the vacuum pipeline between the paint soaking tank and the vacuum unit, and A paint collecting tank is arranged at the bottom of the paint soaking tank, and one end of the paint collecting tank is communicated with the paint soaking tank, and the other end is communicated with the paint delivery pipeline of the paint storage tank through the paint delivery and return valves.

The bottom of the inner cavity of the paint dipping tank is provided with a conical paint collecting plate, the central part of the plate has a paint inlet and return through hole, and the slope from the center of the plate to the tank wall is 6-10°.

The paint collection tank is a closed container structure, and the upper part is provided with a liquid collection valve on the pipeline communicating with the paint soaking tank, and the lower part is provided with a paint delivery and return valve at the part connected with the paint delivery pipeline of the paint storage tank.

The condenser is a tank body closed up and down. A circulating cooling pipe is arranged in the tank body. The water inlet pipe and the water outlet pipe of the cooling pipe are respectively connected with the refrigeration unit. A drain pipe and a drain valve are installed at the bottom of the tank body.

Processing step of the present invention is as follows:

Condensation: Put the workpiece to be impregnated into the paint tank, tighten the tank cover, start the refrigeration unit before starting the vacuum unit, adjust the temperature of the refrigeration unit to -25°C, and send it to the condenser through the cooling pipe of the refrigeration unit 30% ethylene glycol aqueous solution, in the process of starting the vacuum unit to evacuate the paint tank, the gas in the tank (the gas contains styrene and other diluents) is first condensed into liquid through the condenser, and stays in the condensate In the container, it can be discharged and reused regularly.

Vacuuming: close the drain valve, safety valve and paint delivery valve, set the vacuum degree of the primary pump of the vacuum unit to 10000Pa; set the vacuum degree of the secondary pump to 5000Pa; set the vacuum degree of the tertiary pump to 1000Pa; Unit, when the vacuum in the paint tank reaches 5000Pa, the secondary pump starts automatically; when the secondary pump pumps the vacuum in the paint tank to 1000Pa, the tertiary pump starts automatically until the vacuum in the paint tank is pumped To less than 100Pa, the vacuum unit stops.

Vacuum preservation: After the vacuum unit stops, the paint dipping tank will automatically enter the vacuum preservation stage, and the vacuum preservation period will last for 180 minutes;

Paint delivery: After the vacuum time is up, open the paint delivery valve, and under the action of vacuum pressure, the insulating varnish in the paint storage tank will absorb paint into the paint dipping tank under negative pressure through the paint delivery pipeline;

Wet vacuum: when the insulating varnish reaches the set height, close the paint delivery valve, there is still a certain degree of vacuum in the varnish dipping tank, which is wet vacuum, and under the action of this vacuum, keep it for 60-100 minutes;

Vacuum: Open the drain valve on the upper part of the paint tank, so that the entrained gas, styrene free monomer and resin free monomer that escape in the form of bubbles inside the insulating paint are discharged from the paint tank;

Pressurization: Start the pressurized air pump, open the pressurized valve, inject dry nitrogen into the paint tank until the pressure in the tank reaches 0.5-0.8Mpa;

Pressure maintenance: When the pressure in the paint tank reaches 0.5-0.8Mpa, close the pressurization valve, and the paint tank enters the pressure-holding state, and the pressure-holding time is 360-400min;

Pressure release: After maintaining the pressure, open the drain valve to remove the nitrogen in the varnish tank until the pressure in the varnish tank is 0.1-0.2Mpa higher than the atmospheric pressure.

Paint back: Open the paint delivery and paint return valves, and press the insulating varnish back into the paint storage tank through the paint delivery pipeline by the pressure inside the paint dipping tank.

Pressure release: Open the blowdown valve and vent the residual pressure inside the paint dipping tank until the pressure inside the tank is equal to the atmospheric pressure.

Out of the tank: Open the cover of the dipping tank and lift the workpiece out.

The explosion-proof vacuum pressure impregnation insulation device made according to the above scheme can not only effectively solve the problem of insulating varnish and solvent residue in the varnish tank, but also avoid the insulation by the condenser when the vacuum unit evacuates the varnish tank. The flammable and explosive gas in the paint - styrene or other diluents is sucked into the vacuum unit to be solidified and blocked. The device has practical effects such as explosion-proof, safe and reliable, and saving raw materials. At the same time, using the method to impregnate the insulating varnish can reduce the internal dielectric loss of the manufactured high-voltage motor winding coil and improve the service life of the motor.

Description of drawings

Fig. 1 is a structural schematic diagram of a vacuum pressure impregnation insulation device;

Fig. 2 is a process flow diagram of the present invention.

Detailed ways

Referring to Figure 1, the labels in the figure are: paint delivery pipeline 1, paint delivery valve 2, paint storage tank 3, stirring motor 4, pressurized pneumatic valve 5, vacuum pneumatic valve 6, vacuum pipeline 7, refrigeration unit 8, water outlet Pipeline 9, water inlet pipe 10, condenser 11, sewage pipe 12, vacuum unit 13, drain valve 14, paint collection plate 15, paint dipping tank 16, paint collection tank 17, paint delivery and return valve 18, paint collection valve 19. Filter 20.

The explosion-proof vacuum pressure impregnation insulation device of the present invention is composed of a paint dipping tank 16, a paint storage tank 3, a vacuum unit 13, a refrigeration unit 8, a condenser 11, and a paint collection tank 17, wherein the condenser 11 is arranged in the paint dipping tank 16 On the vacuum pipe 7 between the vacuum unit 13, the condenser 11 is a tank body closed up and down, and a circulating cooling pipe is arranged in the tank body, and the water inlet pipe 10 and the water outlet pipe 9 of the cooling pipe are respectively communicated with the refrigeration unit 8, The bottom of the tank body is provided with a drain pipe and a drain valve 14. When the vacuum unit 13 evacuated the paint tank 16, the styrene and other diluent volatiles contained in the gas extracted from the paint tank 16 were condensed into liquid when passing through the condenser 11 before entering the vacuum unit 13, By regularly opening the drain valve 14 at the bottom of the condenser 11, the condensed liquid can be discharged through the drain pipe and reused, thereby avoiding gelation blockage caused by styrene or other diluent volatiles entering the vacuum unit 13 and spontaneous explosion. A paint collecting tank 17 is arranged at the bottom of the paint soaking tank 16, and the paint collecting tank 17 is a closed container structure, and a paint collecting valve 19 is installed on the pipeline communicating with the paint soaking tank 16 on its upper part, and a paint collecting valve 19 is installed on the connecting part of the lower part with the paint conveying pipeline 1. Have lose, return paint valve 18. A conical paint collecting plate 15 is installed at the bottom of the paint dipping tank 16. The central part of the paint collecting plate 15 has a paint delivery through hole communicated with the paint collecting tank 17. The slope of the plate from the center to the tank wall is set to 6 ～10°, the slope should not be too large, so as to prevent the dipped workpieces in the tank from sliding on the sloped paint collecting plate 15 and stacking in the center of the tank. The bottom of the varnish tank 16 is round. When the varnish tank 16 is not working, the insulating varnish deposited on the bottom of the varnish tank 16 and the tank wall naturally flows to the paint input and return port, and flows through the opened paint collection valve 19. The collection is stored in the paint collecting tank 17, so that the remaining insulating varnish in the paint soaking tank 16 is reduced to a minimum. When the paint soaking tank 16 was working, the paint collecting valve 19 was closed. By setting up the paint collecting tank 17, the insulating varnish remaining in the paint tank 16 can be reduced, therefore, in the process of vacuumizing the paint tank 16, there will be less styrene gas or other diluents drawn out, thereby effectively Prevent inflammable and explosive gas from entering the vacuum unit 13, achieve the practical effect of explosion protection, and completely eliminate hidden dangers. Number 4 in the figure is a stirring motor, which is mainly used to drive the stirring blade to evenly stir the insulating paint in the paint storage tank 3 .

In conjunction with Fig. 1, referring to Fig. 2, processing method of the present invention is:

Put the workpiece to be impregnated into the paint dipping tank 16, tighten the tank cover, start the refrigeration unit 8 before starting the vacuum unit 13, adjust the temperature of the refrigeration unit 8 to -25°C, and pass the cooling water of the refrigeration unit 8 into the The water pipeline 10 transports the aqueous solution of 30% ethylene glycol in the condenser 11, then starts the vacuum unit 13, opens the vacuum pumping pneumatic valve 6 and vacuumizes the varnish tank 16, so that the residual styrene contained in the varnish tank 16 and other Before the volatile gas of the diluent enters the vacuum unit 13, it is condensed into a liquid through the condenser 11, and stays in the condenser 11, and the condensed liquid can be periodically discharged for reuse. The practical effect of effectively preventing styrene and other diluent volatiles from entering the vacuum unit 13 to cause gelation blockage and spontaneous combustion explosion is achieved.

The vacuuming process is divided into three stages of vacuuming. When the vacuum in the varnish tank 16 is evacuated to less than 100Pa, the air in the internal gap of the workpiece and the gas containing styrene and other diluents in the varnish tank 16 can be pumped out. And keep the vacuum for 180min. Then open the paint delivery valve 2, and the insulating varnish in the air storage tank 3 is input into the paint soaking tank 16 through the filter 20 through the paint delivery pipeline 1. Paint Valve19. At this time, the impregnated workpiece is completely immersed in the insulating varnish, that is, a wet vacuum is formed in the varnish dipping tank 16 and maintained for 60-100 minutes, so that the insulating varnish enters the interior of the workpiece through negative pressure, fills the gap and fully combines, and at the same time entrains the inside of the insulating varnish. The gas, free styrene monomer, and free resin monomer escape from the insulating varnish in the form of bubbles, and what remains inside the insulating varnish is pure resin and styrene that cannot escape. Using this method, the main purpose is to improve the performance of the high-voltage motor, minimize the gas entering the high-voltage coil insulation, and reduce the dielectric loss inside the motor winding coil.

Then, carry out vacuuming, open the blowdown valve on the blowdown pipe 12, make the entrained gas, styrene free monomer and resin free monomer escape from the varnish tank 16 inside the insulating varnish in the form of bubbles.

The process of pressurization is to use the pressurized air pump to open the pressurized pneumatic valve 5, and press dry nitrogen into the varnish immersion tank 16 to make the pressure in the tank reach 0.5-0.8Mpa, and keep the pressure for 360-400min. During this process, Through the function of the pores inside the workpiece, the insulating varnish can be pressed into the inside of the coil insulation. The pressure release process adopts two pressure releases. The first release is to open the blowdown valve to remove the nitrogen in the paint tank 16, so that the pressure in the paint tank 16 remains at a pressure difference of 0.1 to 0.2 MPa higher than atmospheric pressure. In this way, during the paint back process, the insulating varnish is pressed back into the paint storage tank 3 by the pressure inside the paint dipping tank 16, which can reduce the remaining paint liquid in the paint dipping tank 16, and is also conducive to the leaching of excess paint liquid in the workpiece . After the paint liquid in the dipping tank 16 and the workpiece is drained, carry out the pressure release for the second time until the pressure in the tank is equal to the atmospheric pressure. After the pressure is released, the paint dipping tank 16 can be opened to hang out the workpiece.

Claims (2)

1, a kind of anti-explosion vacuum pressure varnished insulation apparatus, comprise impregnating vessel, storage paint can, vacuum unit, on the vacuum pipe between impregnating vessel and the vacuum unit, have additional the condenser that is connected with refrigerating units, and be provided with the collection paint can in the bottom of impregnating vessel, this collection paint can one end is communicated with impregnating vessel, the other end is communicated with the transmission pipe road of storage paint can by defeated, time lacquer valve, it is characterized in that: described impregnating vessel intracavity bottom is provided with cone shape collection lacquer plate, the centre of this plate has into lacquer, time lacquer through hole, and the slave plate center is 6～10 ° to the gradient of tank skin.

2, a kind of process that is used for claim 1 anti-explosion vacuum pressure varnished insulation apparatus, it is characterized in that: described process may further comprise the steps:

Condensation: impregnated workpiece is put into impregnating vessel, tighten cover, before the vacuum unit starting, start refrigerating units earlier, the refrigerating units temperature is adjusted to-25 ℃, and in condenser, carry the aqueous solution of 30% ethylene glycol by the cooling pipe of refrigerating units, in the process that startup vacuum unit vacuumizes impregnating vessel, gas in jar is condensed into liquid by condenser, and is trapped in the condenser, regularly discharges reuse;

Vacuumize: close blowdown valve, safety valve and defeated lacquer valve, the vacuum degree of the one-level pump of vacuum unit is set to 10000Pa; The vacuum degree of two stage pump is set to 5000Pa; The vacuum degree of triplex is set to 1000Pa; Start the vacuum unit, when the vacuum degree in the impregnating vessel reached 5000Pa, two stage pump started automatically; When two stage pump was extracted into 1000Pa with the vacuum in the impregnating vessel, triplex started automatically, and vacuum degree is extracted into less than 100Pa in impregnating vessel, the vacuum compressor emergency shutdown;

The fidelity sky: behind the vacuum compressor emergency shutdown, impregnating vessel enters the empty stage of fidelity automatically, the empty 180min of fidelity;

Defeated lacquer: after the empty time of fidelity arrives, open defeated lacquer valve, under the vacuum pressure effect, the insulating varnish in the storage paint can is inhaled lacquer by transmission pipe road negative pressure in impregnating vessel;

Wet vacuum: insulating varnish is passed to the height of setting, closes defeated lacquer valve, still has certain vacuum degree in the impregnating vessel, is wet vacuum, under the effect of this kind vacuum, keeps 60～100min;

Put vacuum: open the blowdown valve on impregnating vessel top, gas-entrained, the styrene free monomer and the resin free monomer that are overflowed with bubble form in insulating varnish inside are got rid of in impregnating vessel;

Pressurization: startup adds compression pump, opens pressurizing valve, and in the nitrogen injection impregnating vessel with drying, extremely a jar internal pressure reaches 0.5～0.8Mpa;

Pressurize: when the pressure in the impregnating vessel reaches 0.5～0.8Mpa, close pressurizing valve, impregnating vessel enters packing state, pressurize 360～400min;

Put pressure: after the pressurize, open blowdown valve, the nitrogen in the impregnating vessel is got rid of, be higher than atmospheric pressure 0.1～0.2Mpa to the impregnating vessel internal pressure;

Return lacquer: open defeated, time lacquer valve, insulating varnish is pushed back in the storage paint can by the transmission pipe road by the impregnating vessel pressure inside;

Put pressure: open blowdown valve, with the overbottom pressure emptying of impregnating vessel inside, equal to jar internal pressure and atmospheric pressure;

Go out jar: open the dipping lacquer cover, workpiece is hung out.

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