CZ306766B6 - A modified explosion tube for core shooting machines - Google Patents

Abstract

The modified explosion tube (9) for core shooting machines consisting of the tubular portion (17) provided with the upper and lower flanges (13, 14), while, along the edge of the tubular portion (17), there are formed the apertures (18) in the edge belts (15), while the wall of the tubular portion (17) contains, defined from the inner diameter to the outer one, first inner layer (19) consisting of a vinyl ester resin containing silicon carbide dust, on this inner layer (19), there is placed the glass fibre mat (20) which serves as the first reinforcement on this mat (20), the second layer (19a) is placed, again of a vinyl ester resin containing silicon carbide dust, while on it, there is arranged the third layer (21) formed in layers of coiled glass fibres interlayed with the vinyl ester resin, while the glass fibre in this third layer (21) forms the second reinforcement for significantly increasing the overall stiffness and stability of the tube (9), and, on the third layer (21), there is arranged the outer layer (22) consisting of the vinyl ester resin.

Description

Modified shot tube for core shot machines

Technical field

The invention relates to the problem of firing foundry cores on firing machines. The core part of each firing machine is the firing tube.

BACKGROUND OF THE INVENTION

The shotguns are characterized by rapid loading of the jade with a batch of core mixture that is not mixed with air. The necessary acceleration is given to the mixture in the firing chamber by rapid expansion of the compressed air. This acts on the mixture column from the front as a flexible piston. The friction of the mixture against the chamber walls can be reduced by providing compressed air also through slots in the firing sleeve. The column of the mixture is thus separated from the wall by an air layer. Due to the reduced friction, the mixture is greatly accelerated. A good filling of the ice will occur.

Generally the following process occurs in the production of the foundry core - by so-called firing:

The core mix according to the defined recipe is mixed in the hopper. The recipe consists of foundry sanding and binder. Foundry sanding is mostly formed by quartz sand of defined granulometry. Binders consist of chemical components based on resins. The core mixture is carried from the hopper to the firing tube through the shutter until the shutter is closed.

The core mixture is then purged from the injection tube for a defined period of time and at a defined pressure into the core. Subsequently, the core mixture is cured in the cavities of the jade and a foundry core is formed. The core for forming cores is known, for example, from CZ 266 905 B1. A device for firing and releasing cores from a jade on firing machines used in foundries for the manufacture of cores, wherein the direction of the axis of the firing orifice is identical to the direction of movement of the ejector is known from CZ 209 794 B1. A method and apparatus for producing molds and cores, in particular for foundry purposes, is known from document CZ / EP 1 957 218 T3. The device for producing cores is known from US 000004815517 A. The injection machine is described in WO 2008/125 140 A1. An injection device on a core-firing machine is known from EP 0 255 876 B1.

Currently, the tubes are made of epoxy resin layers interspersed with reinforcing mesh and the flanges are plastic.

Due to the use of the tube, the wear is gradually worn down to the serviceability limit state.

During the clamping of the firing tube, the residues of the core mixture gradually adhere to the aluminum flanges. After clamping the tube, the flanges undergo irreversible deformation of the flanges on the flanges, resulting in a total leak of the system as the compressed air passes.

When the tube is filled with the core mixture and the core tube is emptied, there is excessive abrasive wear resulting from the granulometry of the core mixture used. Gradual abrasive wear leads to material loss on the wall thickness and gradual slimming. The lower wall thickness of the tube is characterized by a decrease in the strength of the tube and a reduction in the rigidity of the tube (fiberglass begins to fray).

Due to the gradual fouling of the air intake and outlet sieves of the firing tube, the air throughput is reduced until the state of the cracks on the tube body.

- 1 GB 306766 B6

Due to damage to the tube sheath, the integrity of the tube sheath surface integrity is impaired. On contact of the binder with the tube sheath, a reaction occurs between the tube body and the binder. As a consequence of the reaction, the integrity of the surface of the fiberglass is accompanied by a decrease in strength. The above mechanism causes cracks in the tube.

Manipulation and assembly of the firing tube leads to dynamic stress and gradual destruction. The systematic mechanical and chemical cleaning of the firing tube leads to surface damage and hence homogeneity of the tube surface, contributing to the degradation of the fiberglass sheath.

It is an object of the present invention to provide a firing tube for core firing machines of a new design, which would have a several times longer service life than currently used pipes.

SUMMARY OF THE INVENTION

The above drawbacks are overcome by the modified injection tube for core injection molding machines according to the invention, characterized in that the wall of the tube portion comprises, defined from an inner diameter to an outer, a first inner layer consisting of a vinyl ester resin containing silicon carbide dust; a glass fiber mat deposited on the inner layer as the first reinforcement; a second layer deposited on this mat, again of vinyl ester resin containing silicon carbide dust; and on said second layer a third layer formed in layers by a winding glass fiber interleaved with a vinyl ester resin, provided that the glass fiber in the third layer forms a second reinforcement for significantly increasing the overall rigidity and stability of the tube, and layer of vinyl ester resin.

In a preferred embodiment, the upper flange and the lower flange are made of aluminum.

Clarification of drawings

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the drawings, in which Fig. 1 is a view of the entire firing machine, in schematic section Fig. 2 is a detail of the firing tube;

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, there is shown a firing machine 1 consisting of a firing chamber 2 with a flange 3 through which the core mixture inlet 4 passes and which is closed by a butterfly flap 5. Inside the firing chamber 2 an firing tube 9 is arranged. a compressed air supply 6 to the chamber 2 and a pneumatic cylinder 7 controlling the air supply are provided. On the opposite side of the chamber wall there is a discharge of compressed air 8. The firing tube 9 is provided with an upper flange 13 and a lower flange 14. Below the lower flange 14 there is a firing plate 10 of the shroud 11 in which a core 12 is formed. holes are provided in its upper and lower portions 18. Thus, the design of the machine and the tube is standard and known in the art. As mentioned above, the tubes are currently made of epoxy resin layers interspersed with reinforcing mesh and the flanges are of plastic.

FIGS. 2 and 3 show an injection tube 9 according to the invention. The tube 9 is generally of the conventional construction described above, except that its tubular portion 17 between the flanges is formed in a different manner, as best seen in FIG. 3 in a detail of a cross-section through the wall of the tube 9. It can be seen that the tubular portion 17 The inner layer 19 of the wall of the tube 9 is composed of a vinyl ester resin into which silicon carbide dust is mixed. A glass fiber mat 20 is wound onto this layer as the first reinforcement. A second dust-containing vinyl ester resin layer 19a is applied to this mat 20

Silicon carbide. The third layer 21 arranged thereon is formed in layers by winding glass fiber interleaved with a vinyl ester resin, the glass fiber in this third layer 21 forming a second reinforcement. The outer layer 22 is a vinyl ester resin. It can be seen that the most stressed inner layer 19 containing silicon carbide dust has the smallest thickness. The presence of the inner layer 19 with silicon carbide dust ensures high abrasion resistance, thereby substantially increasing the life of the tube 9. Since the third layer 21 and the outer layer 22 are essentially of the same material as the main component of the inner layer 19, i.e. vinyl ester resin, For example, the tube 9 has a very good overall stability and mechanical resistance. After the tubular portion 17 has been produced, the edge strips 15 are turned and a central raised portion 16 is formed, thereby providing space for standard covering of the holes 18 formed in these edge strips 15.

Innovative fitting of the tube with aluminum flanges 13 and 14 is also an indisputable advantage, since unlike plastic flanges, these can be further processed after boiling (boiling + machining) and subsequently used in perfect condition, while plastic flanges are irreparable after deformation.

Claims (2)

Modified firing tube for core firing machines, consisting of a tubular part provided with an upper and a lower flange, openings in the edge strips are formed at the edge of the tubular part, characterized in that the wall of the tubular part (17) comprises, defined from the inner diameter to an outer, first inner layer (19) comprising a vinyl ester resin containing silicon carbide dust; a glass fiber mat (20) deposited on the inner layer (19) as a first reinforcement; a second layer (19a) deposited on the mat (20), again of a vinyl ester resin containing silicon carbide dust; and on said second layer a third layer (21) formed in a layer of superimposed glass fiber interleaved with a vinyl ester resin, provided that the glass fiber in this third layer (21) forms a second reinforcement for significantly increasing the overall rigidity and stability of the tube (9) and that on the third layer (21) an outer layer (22) formed of vinyl ester resin is provided. Modified firing tube according to claim 1, characterized in that the upper flange (13) and the lower flange (14) are made of aluminum.