SU996069A1 - Apparatus for applying paint onto interior surface cylindrical casting moulds - Google Patents

Description

(5) DEVICE FOR DRAWING PAINT ON THE INTERNAL SURFACE OF CYLINDRICAL CASTING FORMS

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The invention relates to foundry, in particular, to devices for coating the inner surface of casting molds and cores and can 6) iTi is used to apply refractory paints to the working surface of molds or molds for centrifugal casting.

A nozzle for applying material to the inner surface of the body is known, and rotational rotation is (. Nagfimer. Rub (% |) containing reflective discs installed with a gap and forming a radial annular slot for the passage of material. This device is o | Be: Ensures the possibility of adjustment dispersiveness of droplets and gives high performance fl.

However, it provides a sufficient degree of averaging of the fluid-to-bone mixture of air and gives its low densification.

A sprayer is also known, comprising a housing with a feed channel, a core and a reflector forming a channel with the outlet conical section of the spray housing. Reflector. securing the core on the core with the possibility of axial movement, is made in the form of a cone, having a conical recess along the base perimeter. The device allows to increase the spraying efficiency 2.

A disadvantage of the known sprayer is the low turbulence of the sprayed substance, as a result of which the average of its composition is.

Closest to the proposed technical essence is a device for applying paint on the walls of the mold, containing a cylindrical chamber. on a tangent to the inner wall of which, on two opposite sides, are pipes for supplying paint and air, reflective discs installed with a gap and forming a radial annular slot. In the device, a mixture of paint and air flows from the cylindrical chamber into the space between the disks through the central opening and is sprayed through the annular gap between the disks. The device eliminates rotating parts, increases reliability and simplifies its design. 3 A disadvantage of the known device is the low pipelability of the mixture flow in the space between the disks and, as a result, the lack of mixing and averaging of its composition. The application of such a mixture on the painted surface does not allow to obtain a sufficiently uniform layer, due to which the quality of the cast products is reduced. The purpose of the invention is to improve the quality of coloring the surface of the casting mold by increasing the degree of dispersion of the sprayed paint. The aim is achieved in that the device for applying paint on the inner surface of the wall of cylindrical molds on the surface of the cylindrical base and. pse.dvosphere is filled with a three-way screw groove with a lifting angle, having the shape of a circular segment in cross section, on the surface of the cylindrical base of the screw groove in cross section is made in the shape of a semicircle with a radius equal to 0.10-0.16 of the diameter of the cylindrical base beginning with the interface of the cylindrical base and the pseudosphere and up to the interface with the plate, the screw groove is made with uniformly decreasing in length to zero depth and uniformly increasing corresponding to a width equal to the diameter of the plate in the interface of the pseudosphere with the plate 0,. FIG. 1 schematically shows the proposed device; general form; in fig. 2 - the same, top view; in fig. 3 - spray; in fig. k is a diagram of a laboratory setup for testing the proposed device; in fig. 5 is a graph of tests of the prototype and the proposed device. The device for applying paint to the inner surface of cylindrical casting molds, mainly for casting rolls, consists of a cylindrical chamber 1, to the side surface of which are tangential from two diametrically opposite sides embedded pipes 2 and 3 for supplying paint and air coaxially with a nebulizer consisting of smoothly conjugated cylindrical base k, pseudosphere 5, plate 6, on the surface of which a three-way screw groove 7 is made with a lifting angle 25-; in cross section on the surface of the cylindrical base k, the shape of a semicircle with a radius of 0.10-0.16 diameters of the base, and starting from the mating section of the cylindrical base 4 with pseudosphere 5 and up to the mating section with the plate 6, the screw groove 7 is made. a uniformly decreasing in length to zero depth and a uniformly increasing width equal to the interface of the pseudosphere with the plate O, the diameter of the plate and the top cover 8 with the central hole 9. In addition, the device contains a hose 10 for supplying paint, a hose 11 l of air supply tank 12 to ink pouring spout 13, valves Sh Operation is carried out as follows. The paint and air are supplied under pressure, respectively, through the pipes 2 and 3 into the cavity of the cylindrical chamber 1, while the flows of paint and air are mixed, creating a mixture. After a sufficient pressure has been created in chamber 1, the process of spraying the paint-air mixture through the screw grooves 7 of the spray gun begins. The screw groove 7 is three-way due to the fact that it provides the most optimal conditions for uniform spraying of the paint mixture with air. If the helical groove is double or single-threaded, to create a throughput section sufficient for optimal spraying, the grooves must be made with a depth that does not provide sufficient mechanical strength of the spray gun (i.e., when the depth of the groove approaches the radius of the base. Making the groove more than a three-way, creates the need to make the grooves with too shallow depth, which is unjustified from a design and technological point of view. As a result, the screw groove The expediency of making a helical groove in such a way that in cross section it has the shape of a semicircle with a radius of 0.10-0.16 base diameter in the section of the cylindrical base k, which is in the form of a groove the most optimal for a stable flow of paint over it is eliminated. The possibility of accumulation and adhesion of paint on the surface of the groove, that tip-5 makes it possible to stop the work of the proposed device. The radius of the groove is selected within 0.10-0.16 diameters of the cylindrical base k, since if this value decreases below 0.10, the groove throughput, determined by the sum of the transverse areas of the three grooves, is not enough for the paint to pass through the grooves there is the possibility of sticking them with paint. As the radius of the grooves increases in excess of 0.1b of the diameter of the cylindrical base, the mains air flow rate is insufficient to create pressure in the paint flow, ensuring an optimal paint release rate from the device and, therefore, a necessary increase in the degree of dispersion of paint. As a result, the semicircle radius is selected within the range of 0.10-0.16 of the diameter of the cylindrical base. The positive effect of making a helical groove with an elevation angle is due to the fact that if this angle decreases below 25, the path taken by the paint along the helical groove is unnecessarily lengthened, which creates the danger of the last paint sticking and stopping operation. In the case of an increase in the angle of elevation in excess of 5 °, the path traveled by the Krai, it becomes insufficient for it to obtain a circumferential speed sufficient for efficient spraying. As a consequence, the magnitude of the elevation angle of the screw groove is chosen within the limits. The feasibility of screw grooves in such a way that starting from the mating section of the cylindrical base k and pseudosphere 5 and up to the mating section with the plate 9

Claims (3)

creating at the exit of the device a continuous uniform annular jet. In this case, favorable conditions are created for the complete connection of the three paint streams at the outlet of the device. If the helical groove is made in such a way that, at the interface of the pseudosphere with 96069 6, it is made with a uniformly decreasing depth to zero and an equally-increasing width equal to at the interface of the pseudo sphere with a plate of 0.9 "2-1 , the diameter of the plate, due to the need for a plate, it does not come to naught, conditions are created to divide the flow of paint into separate streams, in this case into three streams, as a result of which the jet uniformity is disturbed, which, in turn, leads to unevenness coating and reduce the quality of the surface of the casting. The positive effect of making the helical groove width at the interface of the pseudosphere with the plate 6 within 0, 0, 6 of the diameter of the plate is due to the fact that to create a uniform annular jet at the exit of the device, the three-way screw groove, performing up to this section the function of unwinding, t . the device increasing the peripheral speed is drained from the plate, and the outgoing three streams are merged into one ring. On this basis, the width of each groove in the interface of the pseudosphere 5 with the plate 6, measured on the circumference of the plate, is equal to 3 / 10-1 / 3 the length of the circle of the plate or B (3/10 - 1/3) / C-D, where B is the groove width measured on the circumference of the plate; D is the diameter of the plate. Substitute the numerical value of 7G, we obtain B 0, –1,046) –D In identical conditions, a device for applying paint to the surface of the mold is tested, containing a smooth sprayer (prototype) and the proposed device of five types: in the 1st screw groove: on with an elevation angle of 20, in the 2nd 25, in the 3rd 35 °, in kS ° and in the 5th 55 I, each of these devices is made with a radius of the grooves R equal to 0.07; 0.10; 0.13; 0.1b and 0.19 times the diameter of the cylinder. From the tank 10, paint through the hose 12 through the nozzle 2 is supplied to the device under test with a cylindrical chamber 1 with a diameter of 100 mm. Through hose 11, through pipe 3, a stream of air is supplied from the compressor at a pressure of 2 MPa. The paint-air mixture sprayed with the device under test is applied to the inner surface of a metal hollow cylinder with a diameter of 350 mm. The uniformity of the applied paint layer is determined by a difference optical method on a microscope having a measurement accuracy of 1 µm. The uniformity of C.T.S coating is determined using the formula CT.S "Sway-Stnin. loQ wax shzh, respectively, the maximum and minimum thickness of the applied layer. From the results of the experiments, it can be seen that the uniformity index of the coating for the prototype is about 80 (in Fig. 4, indicated by a dot). Experimental and devices with different sprayers allow us to determine that the most optimal are sprayers with helical grooves and having a lifting angle of 25 -. The best results are given by the grooves on the surface of the cylindrical base of the atomizer the shape of a semicircle with a radius equal to 0.10 0.16 of the base diameter, and starting from the interface of the cylindrical base and pseudosphere and up to the section of coupling with the keyhole, the spiral groove made with a uniformly decreasing true to zero depth and a uniformly increasing width, equal to Hia, the interface area of the pseudosphere with the plate 0, the diameter of the plate, which has a uniformity index of the coating equal to 25-35. The proposed device allows improving the surface quality of molded products by increasing the degree of dispersion of the sprayed agent and improving the uniformity of the applied layer. The expected annual economic effect from the introduction of the proposed invention will be 92 thousand rubles. Claim 1. Device for applying paint on the inner surface of cylindrical molds, containing coaxially arranged cylindrical chambers J whose side surfaces are tangential from two diametrically opposite sides are fitted pipes for paint and air supply, a lid with a hole in the center and a spray gun cylindrical base, pseudosphere and plate, which is so that, in order to improve the quality of painting the surface of the mold due to lichenie degree of dispersion of atomized paint on the surface of the cylindrical base and the pseudo atomizer trehzahodna formed with a helical groove helix angle, having a cross sectional shape of a circle segment. 2. The device according to claim 1, wherein the groove in the cross section of the cylindrical base of the screw nozzle is made in the shape of a semicircle with a radisome equal to 0.10-0.16 of the diameter of the cylindrical base. 3. The device according to claim 2, wherein it is from, the interface of the cylindrical base and the pseudosphere and to the interface of the pseudosphere with the screw groove is made with a uniformly decreasing length to zero and a uniformly increasing width equal to the area of the conjugation of the pseudosphere with tarvlyu 0, the diameter of the plate. Sources of information taken into account in the examination 1. The author's certificate of the USSR 585262, cl. B 05 B 13/06, 1976. 2. USSR author's certificate number 725712, cl. B 05 B 1/26, 1978. 3. Authors certificate of the USSR N 263820, cl. B 22 C 23/02, 1968, FIG. I CZZJ / jjf (  and t 4zzr V t h Fick Cw3 / K S9 Jw a / S j at 20 S0 Figure 5 I am c (