DD296431A5 - METHOD FOR PRODUCING DICKWOVER TUBE BOOMS - Google Patents

Abstract

A method for producing thick-walled tube sheets, in particular shaped articles designed as tube sheets for high-pressure synthesis and high-pressure polymerization plants, using a semifinished product in which the throughflow channel is drilled out of the solid, according to the invention, such that the semifinished product before drilling out the throughflow channel, according to the wall thickness and the bending radius of the pipe bend is provided with a Kruemmung, then centrically drilled out to the Anschluszquerschnitten the semi-finished product of the flow channel and finally the so prefabricated semi-finished by means of a conventional bending device to the finished pipe bend is completed. Fig. 3 {pipe bend; push fitting; Semi-finished products; flow-through; Wall thickness; Bending radius; Curvature; Anschluszquerschnitt; Bender}

Description

Aim of the invention

The purpose dor invention is a method by which thick-walled Rohrbögon can be produced, which, under the condition of gorlngst possible material use while Bolbuhaltung their full utility value, no or only slight biegetochnioch conditional wall thickness differences and no subsequent angleichondon correction eccentric connection cross sections require.

Explanation of the essence of the invention

The invention has for its object to develop an ancestor, which, using a provided with a drilled outflow semifinished product, produce thick-walled pipe bends with approximately uniform wall thicknesses in all areas of the arc, the Anschlußquerschnilto the pipe bend centric and dimensionally equal to the fittings should be.

According to the invention, this object is achieved in that the originally straight semi-finished before drilling out of the flow, depending on the radius and wall thickness of the pipe bend to be produced, is provided with such a curvature by the, from the imaginary flow passage out and lying in the plane of curvature, inner and outer bending zones of the semifinished product at each point reduced or increased approximately by that amount which is required to compensate for the material flow during the subsequent bending process of the actual pipe bend in size in these zones, so that at the end of this bending process, the inner and outer wall thicknesses of the pipe bend have equalized in size to each other.

That the semi-finished product pretreated in this way is now provided with the flow channel, in that it passes through the pre-curved semi-finished product, penetrating centrally at one end and emerging centrally at the other end. That finally by necessary pretreatments (such as provided with filler and hermetically sealed) prepared semi-finished, in its plane of curvature aligned to the bending radius center of the pipe bend to be produced, receives its final shape by means of a corresponding device, at the end of this bending process of the desired and by the pre-curvature realizable effect of a substantial wall thickness approximation in the bending zones, at the same time formed centrically Anschlußquorschnitten occurs.

embodiment

The invention will be explained in more detail using an exemplary embodiment.

It shows the pipe bend once in the form of a semi-finished product with a drilled-out flow channel before the actual bending process and on the other hand in its finished form.

1 and 2: show the semifinished product and the pipe bend according to the usual procedure in longitudinal section Fig. 3 and 4: show the semifinished product and the pipe bend according to the procedure according to the invention in longitudinal section.

In the embodiment, it is a pipe bend with a bending angle α of 90 ° and on both sides straight connecting piece.

From the comparison of Figures 1 and 2 to Figures 3 and 4, the crucial difference in the process according to the design of the semi-finished products can be seen. While the semifinished product is used in a straight shape according to FIG. 1 and is traversed by an eccentrically arranged throughflow channel, FIG. 3 shows a semifinished product provided with a curvature, the throughflow channel of which is arranged centrically to the connection cross sections. Assuming a required minimum wall thickness a, corresponding to the predetermined connection cross-section according to FIGS. 2 and 4, the outer diameter d of the semifinished product in FIG. 1 increases by the eccentricity χ to the enlarged outer diameter D. FIG. 2 shows a pipe bend from a according to FIG 1 used semi-finished product, in which the outer diameter D can take the smallest possible degree, provided that the tensile bending zone of the pipe bend just reaches the minimum wall thickness a; the flexurized bending zone inevitably increases to the wall thickness b. If the wall thicknesses a and b are equal to each other, the flow channel is even more eccentric to drill, resulting in a further enlarged outer diameter D entails. The only in cross-section apparent in Fig. 2, but in reality, however, extending around the pipe bend, marked as black areas excess material must, as already explained in the description, be processed consuming. On the other hand, Figure 4 shows a pipe bend from a semifinished product used in accordance with FIG. 3, in which, due to the process-related pre-curvature of the invention, the originally too low in the printing area, and the wall thicknesses originally too large in the tensile area, at the end of Biegeyorganges on have a uniform wall thickness, in this example to the minimum wall thickness a, approximated.

Claims (2)

1. A method for producing thick-walled pipe bends, wherein a provided with a drilled out flow semi-finished application, characterized in that the originally straight semi-finished is provided before drilling out of the flow-through with a curvature, that then the flow channel, centrally in the one end of the pre-curved Semi-finished penetrating and centric emerging at the other end, is drilled out and that eventually the so-prepared semi-finished, aligned in its curvature plane to the bending radius center of the pipe bend to be produced, receives its final shape by means of a conventional bending device. 2. The method according to claim 1, characterized in that the curvature of the semifinished product is carried out by the, viewed from the imaginary flow-through as well as lying in the plane of curvature, inner and outer bending zones of the semifinished at each point reduced or increased by one measure form, which is necessary to compensate for the material flow during these subsequent bending process of the actual pipe bend in size in these zones. For this 1 page drawings Field of application of the invention Processes of this type can advantageously find application where pipe bends are exposed, which are exposed in their intended operational use high heat and / or Druckparametorn and accordingly, compared to the inner diameter, must have extremely large wall thicknesses. Characteristic of the known state of the art Thick-walled pipe bends are produced with the aid of suitable devices predominantly in the heated state, while adhering to certain bending process steps. If the pipe cross-section in the bending area to change as little as possible, there is a support of the pipe wall by a filler, usually sand, which fills the pipe interior between the hermetically sealed pipe ends. Although this measure contributes to the fact that the inner contour of the pipe retains its original shape within certain limits, but can not prevent, in particular from the bending radius center of view, lying in the bending plane inner or outer zones of the pipe bend due to compression or Thicken or reduce the elongation of the material. The result is a non-uniform wall thickness in the entire bending area with the consequent negative impact on the performance of the pipe bend, in particular with respect to its reduced capacity to internal overpressure. This makes it necessary to use an over-dimensioned pipe with a correspondingly larger wall thickness and thus larger outside diameter in order to guarantee the required minimum wall thickness in the largest expansion zone. Particularly unfavorable affects this inevitable expansion-compression process in pipe bends, which in addition to a large wall thickness have a low bending radius, as z. B. is the case with fittings for Hochdrucksynthese- and Hochdruckpolymerisationsanlagen. In such products, due to a non-available in the required dimension and material quality hollow semi-finished product, the flow-through before being bent from full bar material drilled. In order to counteract the unfavorable Wandstärkenve change resulting from the described effect of material thickening and reduction in the bending zone, therefore, in practice, the flow-through is not centric, but eccentric drilled. This results in a hollow body, which lies in the bending plane inner and outer wall in their strength within a limited range a certain approximation, provided that the eccentric deviation of the flow is aligned during the bending operation to the center of the bending radius. This measure has the effect that the extreme wall thickness differences occurring in the endangered region of the pipe bend are avoided and, as a result, the cost of materials is reduced compared with a centrally arranged throughflow channel; however, there are still remaining or newly incurred disadvantages. So z. As compared to a cast pipe bend, with otherwise the same underlying wall thickness, the outer diameter of the starting material of the pipe bend to be bent to the extent of deviating from the center eccentricity of the Durchsirömkanals larger. This means per pipe bend further increased material costs of mostly high-alloyed materials. An additional disadvantage is that the eccentric cross section of the bow ends does not coincide with the central cross section of the fittings. For structural and aesthetic reasons, a working off of the material deviating from the central cross-section in the connection region of the pipe bend to align with the subsequent construction parts is required. This results in a considerable amount of work time and machine capacity.