RU2820888C1 - Casting vacuum impregnation plant - Google Patents

Abstract

FIELD: foundry.

SUBSTANCE: apparatus for vacuum impregnation of castings includes impregnation (1) and flushing (2) chambers with membrane valves fixed on a metal podium. Impregnation chamber is connected by pipelines with vacuum pump (8), container with impregnating composition (9), receiver (5) for compressed air, separator (4) for separation of liquid coming from pipelines from air, compressor (14) for injecting excess pressure, flushing chamber and electromagnetic vacuum valve (6) creating cyclic negative pressure during evacuation. Flushing chamber is connected by pipelines to tank with alkaline solution (10), drainage and, through three-way valve, to said compressor, electromagnetic vacuum valve, vacuum pump, receiver and separator. Three-way valve (13) switches the installation to the modes of cleaning the castings in the washing chamber, removing air from the pores of the castings in the impregnation chamber, impregnation of castings with impregnating composition and polymerisation of impregnating composition in flushing chamber.

EFFECT: cleaning and sealing of surface pores of casts.

1 cl, 2 dwg, 2 tbl

Description

The invention relates to foundry production, in particular, to the design of devices for impregnation of porous castings with a sealing composition.

A known installation for impregnation of castings [1], which includes a container fixed in a frame, containing a central post mounted on its bottom with a conical tip that can rotate, and with a bearing fixed at the base of the post.

The disadvantage of this installation is the significant limitation of the geometry of the castings to be impregnated due to the placement of the stand in the center of the tank bottom, as well as the complexity caused by the need to use a hydraulic, pneumatic and rotation drive.

A known installation for vacuum impregnation of armatures, coils and stators [2], containing an impregnation chamber, a container for the compound, a vacuum pump and pipelines, and a receiver.

Its disadvantages include the absence of a component responsible for creating excess pressure in the impregnation chamber, which does not allow for high productivity of the installation, since to completely impregnate the castings the cycle must be repeated 2-3 times.

The closest to the proposed solution, chosen as a prototype, is a mobile vacuum impregnation installation [3], containing a loading box for laying products, an impregnation reservoir, a vacuum pump, a storage tank for impregnating resin with a filling valve and a water drainage area, the loading box is made in the form of a perforated sheet, the impregnation tank is in the form of a sealed bag made of highly elastic transparent film with tubular clamps, which performs the functions of a washing tank and a polymerization tank, while the installation is additionally equipped with an instantaneous water heater and a circulation pump included in a single circuit with a sealed bag, and the bag is equipped with three fittings connecting it with corresponding three-way valves to the said circuit, a vacuum pump, a container for storing impregnating resin located below the level of the sealed bag, and through a shut-off valve with a water drainage area made in the form of drainage.

The prototype does not ensure deep penetration of the sealing composition into the pores of the casting due to the absence of a component in the installation that provides the ability to create excess pressure in the impregnation tank. Additional difficulties are created by the fact that a multifunctional sealed bag made of highly elastic material, after applying a vacuum, can be pressed against the walls of the casting, preventing it from fully performing the declared functions of a washing tank and a polymerization tank.

The objective of the present invention is to create a vacuum impregnation installation that guarantees high-quality cleaning from dirt, oil, coolant, etc. and impregnation of castings with surface pores, as well as expanding its functionality with the ability to impregnate castings both under vacuum conditions and overpressure in the impregnation tank, and improving the controllability of the production process.

The technical result achieved by implementing the invention is to ensure more complete and effective cleaning from dirt, oil, coolant, etc. and sealing large, medium and small pores located on the surface of the castings and increasing the pressure level at which the tightness of the casting is broken after impregnation in comparison with the prototype.

The technical result is achieved by the fact that in the proposed installation for vacuum impregnation of castings, which includes an impregnation reservoir, a vacuum pump, an instantaneous water heater, a circulation pump, a container with an impregnating composition, a vacuum gauge, a thermometer, shut-off valves, three-way valves, a separator, drainage, and a base , additionally contains an electromagnetic vacuum valve, diaphragm valves, a compressor, a receiver, a container with an alkaline solution, a washing chamber, a metal podium for attaching the impregnation and washing chambers and a casing.

The proposed installation for vacuum impregnation of castings is presented in Figure 1 (pipelines connect parts of the installation both functionally (transportation of the impregnating solution, water, air) and structurally (through flange connections, joints and welding).).

The installation for vacuum impregnation of castings contains the following parts, which are in structural unity and together ensure the practical implementation of its functional purpose:

1 – impregnation tank, which is a vertically located cylindrical vessel with a hermetically sealed lid; 2 - washing chamber; 3 – instantaneous water heater; 4 – separator; 5 – receiver; 6 – vacuum solenoid valve; 7 – circulation pump; 8 – vacuum pump; 9 – container with impregnating composition; 10 – container with an alkaline solution; 11 – thermometer; 12 – pressure and vacuum gauge; 14 – compressor; 13, 16 – three-way valves; 15, 17, 18, 19 and 20 – shut-off valves; 21, 22 – membrane valves that automatically close under vacuum; 23 – metal podium for mounting the impregnation and washing chambers; 24 – casing; 25 – base, 26 – drainage.

To ensure its compactness, all parts of the installation for vacuum impregnation of castings are located relative to each other with minimal gaps, allowing for a complex of installation work, and are interconnected by assembly operations (screwing, joining, welding), ensuring structural unity and implementation of the device for general functional purposes (functional unity) , and are rigidly fixed in a frame (not shown in figure 1) or on a base 25, which can be either a frame or a special pedestal, floor or foundation of a production area.

Reservoir for impregnation 1, shut-off valve 18 and a container with impregnating resin 9 in conjunction with a vacuum pump 8, which creates negative pressure (vacuum), a receiver 5, which serves to store compressed air before it is supplied to the pipeline system , and a pressure and vacuum gauge 12 for measurement vacuum pressure, a separator 4, which facilitates the separation of incoming liquids from the system from the air, a vacuum solenoid valve 6, which operates cyclically during impregnation and cleaning of castings, a three-way valve 13 for switching the operating mode of the installation for cleaning and impregnation of castings, a membrane valve 21, which ensures sealing of the tank for impregnation 1 when applying a vacuum, a compressor 14, which pumps excess pressure into the impregnation reservoir, and a shut-off valve 15 ensure high-quality impregnation of the castings with a sealing compound. The washing chamber 2, the shut-off valve 17 and the container with the alkaline solution 10 in conjunction with the membrane valve 22, the vacuum pump 8, the receiver 5, the separator 4, the pressure and vacuum gauge 12, the vacuum solenoid valve 6 are sequentially structurally connected by pipelines through a three-way valve 13 and ensure the cleaning of castings before impregnation. Circulation pump 7, which serves to forcibly supply the system with liquid, instantaneous water heater 3, for heating water, is structurally connected to flushing chamber 2 by a pipeline system, three-way valve 16 to create a closed circuit, thermometer 11 for measuring the water temperature in the system, shut-off valve 19, shut-off valve 20 and drain 26, into which water is drained, jointly ensure the process of washing the castings after impregnation and polymerization of the impregnating composition. The impregnation reservoir 1 and the washing chamber 2 are mounted on a metal podium 23. The casing 24 is designed to ensure isolation of the working area of the installation and safe working conditions for production personnel. The base (foundation) 25 is intended for mounting all parts of the installation.

Cleaning castings from dirt, oils and coolants and removing them from the surface pores of parts is possible only with the joint operation of the vacuum pump 8, receiver 5, separator 4, vacuum solenoid valve 6, structurally connected by a pipeline system and a three-way valve 13 with a flushing chamber 2, which in turn connected to container 10 filled with an alkaline solution. Impregnation reservoir 1, container with impregnating composition 9, compressor 14, vacuum pump 8, receiver 5, separator 4, vacuum solenoid valve 6, piping system and three-way valve 13 in functional and structural unity provide high-quality impregnation of pores exposed to the surface with a sealing composition castings In this case, the creation of a vacuum during evacuation occurs due to the cyclic operation of the vacuum solenoid valve 6, and the operation of the compressor 14 to create excess pressure contributes to a deeper penetration of the sealing composition into the pores of the casting.

The schematic hydraulic diagram of the installation for vacuum impregnation of castings is shown in Figure 2. The installation operates as follows:

The first operation is cleaning the castings. The castings are placed in the washing chamber 2, it is closed, then the vacuum pump 8 is turned on and the air is pumped out from the receiver 5, reducing the pressure in it to a vacuum of 0.9 MPa. The vacuum solenoid valve 6 is closed. The vacuum solenoid valve 6 and the shut-off valve 18 open. A vacuum is created in the wash chamber 2, due to which the alkaline solution from the container 10 rises into the wash chamber 2. After the wash chamber 2 is filled with an alkaline solution, the shut-off valve 18 closes and the vacuum solenoid valve 6 begins to operate, which opens and closes with a frequency of 1-2 times per second, at the same time the membrane valve 21 is activated and a hydraulic shock occurs, as a result of which the alkaline solution penetrates the pores of the casting and washes out contaminants from them. In this case, separator 4 protects the system from moisture entering it. The castings are unloaded from washing chamber 2 and dried.

The second operation is “dry vacuum”. To implement this, the three-way valve 13 is switched to the “open” position to provide access to the impregnation tank 1, the castings are loaded into the impregnation tank 1, and it is closed. In the impregnation tank 1, the necessary vacuum is created using a vacuum pump 8, the level of which is controlled by a pressure-vacuum gauge 12. The castings are kept for a certain time with the vacuum pump 8 constantly running, as a result of which air is removed from the pores emerging on the surface of the castings. After reaching the required vacuum level, the third operation is performed.

The third operation is “wet vacuum-pressure”. The shut-off valve 17 opens, and the impregnating liquid from the container with the impregnating composition 9, with the vacuum pump 8 running, enters the impregnation reservoir 1 until it is completely filled. After this, the shut-off valve 17 closes and the castings are kept in vacuum for 10 minutes, then the vacuum solenoid valve 6 begins to operate, which opens and closes with a frequency of 1-2 times per second. In this case, the membrane valve 22 is activated and a hydraulic shock occurs, facilitating deep penetration of the impregnating composition into the pores of the castings. Then the vacuum solenoid valve 6 closes, the compressor 14 is turned on, the shut-off valve 15 opens, the necessary pressure is created in the impregnation tank 1 and the castings are held for 15 minutes. Due to this, the impregnating composition is “fixed” in the pores, displacing the air remaining in the casting. Then the compressor 14 is turned off, the shut-off valve 15 and the shut-off valve 17 open, the impregnating composition flows into container 9 and the impregnated castings are unloaded.

The fourth operation is washing the castings. The castings are immersed in the washing chamber 2, after which it is closed. When the three-way valve 16 is opened, water fills the flushing chamber 2 with running water. Upon completion of filling the washing chamber 2, the tap 16 is closed and the shut-off valve 20 is opened, the water with the remaining impregnating composition is drained into the drain 26.

The fifth operation is polymerization. Valve 20 closes, three-way valve 16 switches to supply running water to wash chamber 2. Once wash chamber 2 is filled with water, tap 16 switches and shut-off valve 19 opens, forming a “closed circuit.” The circulation pump 7 and instantaneous water heater 3 are turned on, heating the water circulating in the circuit to a level of 95-100°C. The water temperature is controlled by thermometer 11. Then it is held at this temperature for 30 minutes, the circulation pump 7 and instantaneous water heater 3 are turned off, the shut-off valve 20 opens, and the water is drained into the drain 26. The castings are cooled and unloaded.

Impregnation is complete.

To test the effectiveness of the proposed technical solution, it was experimentally compared with the prototype. The washing chamber as part of the proposed installation had a volume of 1.5 m ³ and contained an alkaline solution, which consisted of caustic soda and trisodium phosphate with a concentration of 5 g/l each in water, as well as a defoamer with a concentration of 0.1 g/l. The proposed installation included a manual direct-flow vacuum valve with an electromagnetic drive of the Aktan KF25 brand with an operating pressure of up to 0.1 MPa and a maximum pressure drop at the moment of opening of up to 0.5 MPa. Impregnation was carried out with a sealing compound of the Anacrol-90 brand, which polymerizes in water at a temperature of 95±5 °C. The operating temperature range for testing castings after impregnation and polymerization ranged from -60°C to +220°C.

The test took place on three experimental castings, the characteristics of which are given in Table 1. The degree of cleaning of the castings (the presence of dirt, oil and coolant residues on the surface) before impregnation was monitored (using a microscope to determine the size of the pores at their mouth), as well as the pressure at which the tightness is broken after impregnation (using an electric pressure tester with a pressure gauge).

The test results shown in Table 2 showed a higher quality of cleaning and impregnation of castings using the proposed installation in comparison with the prototype.

Information sources:

1. Patent No. 96503 Russian Federation, IPC B01F 9/10 (2006.01), B04B 5/00 (2006.01). Installation for impregnation of castings: No. 2010113057/05: application. 04/05/2010: https://new.fips.ru/registers-doc-view/fips_servlet?DB=RUPMAP&DocNumber=2010113057/05&TypeFile=htmlpubl. 08/10/2010/ Borisov V.V.; - 10 p.: ill. – Text: direct.

2. Patent No. 44210, Russian Federation, IPC H02K 15/04 (2000.01). Installation for vacuum impregnation of armatures, coils and stators: publ. 02/27/2005/ Pelipenko N.A., Pelipenko Y.N.; - 5 p.: ill. – Text: direct.

3. Patent No. 139381, Russian Federation, IPC B22F 3/26 (2006.01). Mobile vacuum impregnation unit: publ. 04/20/2014/ Evdokimov S.V., Komlev V.K., Orlova E.A., Sokolov K.O., Fedorova O.E.; - 7 p.: ill. – Text: direct.

Table 1

Casting Description Overall dimensions, mm
L x W x H Weight, kg Material Pore size at the mouth, mm Frame Thin-walled casting in the form of a parallelepiped with bosses around the perimeter of the flange 450 x 520 x 610 43 SCH20
GOST 1412-85 0.2-0.32 Pipe branch Thin-walled body of rotation with thickened flanges at the edges 600 x 230 x 230 20 AK7ch
GOST 1583-93 0.1-0.18 Brake cylinder Thick-walled cylindrical body 200 x 90 x 90 6 AK9ch
GOST 1583-93 0.17-0.24

table 2

Casting Degree of cleaning before impregnation
(prototype/proposed solution) The pressure at which the seal is broken before impregnation,
MPa Pressure at which the seal is broken after impregnation (prototype / proposed solution), MPa low ^* average ^* high ^* Frame +/- -/- -/+ 0.01 0.1/0.9 Pipe branch -/- +/- -/+ 0.014 0.12/0.84 Brake cylinder -/- +/- -/+ 0.012 0.08/0.65

^* low degree of cleaning - there are oil and dirt residues on the surface;

medium degree of cleaning - there are residual oils and dirt in the pores;

high degree of purification - complete absence of oil and dirt on the surface and in the pores.

Claims (1)

Installation for vacuum impregnation of castings, containing a base with an impregnation chamber placed on it, connected by pipelines to a pressure-vacuum gauge for measuring vacuum pressure with a vacuum pump, a container with an impregnating composition, a receiver for storing compressed air, a separator configured to separate the liquid coming from the pipeline system from the air , characterized in that it is equipped with a casing, a compressor for pumping excess pressure into the impregnation chamber, an electromagnetic vacuum valve configured to create a cyclic vacuum during evacuation, connected by a pipeline to the impregnation chamber, as well as a washing chamber connected through pipelines to a container with an alkaline solution, drainage and, through a three-way valve, with the mentioned compressor, electromagnetic vacuum valve, vacuum pressure gauge, vacuum pump, receiver and separator, while the impregnation and washing chambers are fixed on a metal podium and equipped with membrane valves, the mentioned three-way valve is made with the ability to switch the operating mode of the vacuum installation impregnation of castings to implement modes of cleaning the castings in the washing chamber, removing air from the pores of the castings in the impregnation chamber, impregnating the castings with an impregnating composition and polymerization of the impregnating composition in the washing chamber, wherein the installation for vacuum impregnation of castings contains a flow-through water heater and a thermometer, configured to heat the supplied water into the washing chamber in the mode of polymerization of the impregnating composition, and controlling its temperature.