RU2555693C1 - Device for cylindrical tubes manufacturing for gas filled drift detectors of ionisation radiation - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: working element for ultrasound welding is sonotrode with spherical work surface and installed with possibility of its pressing during welding to the anvil. The feed drum is equipped with adjustable tape tensioner. Stop to form tape in U-shape channel has regulating assembly for accurate positioning of the longitudinal edges of the pipe blank relatively to the sonotrode and anvil. The draw die has device for its accurate positioning relatively to the anvil. The device has carriage to secure in it of the tube end, which has possibility of movement on the guide for the tube drawing. The carriage is provided with nozzle for gas supply under overpressure to the welded tube part. The produced tubes have minimum possible thickness, sufficient strength for operation at gas work pressure inside the tube. Maximum smoothness of the weld internal surface is provided due to exclusion of its edge overhang along the full length.

EFFECT: tubes manufactured using this device ensure low distortion of the electric field inside, this has positive effect on the detector operation.

5 dwg

Description

The field of technology.

The invention relates to the manufacture of welded pipes, as well as to the manufacture of coordinate gas-filled radiation detectors and can be used in the field of experimental physics, molecular biology, metallophysics for work in flows of charged particles or x-ray radiation. The drift tube is a plastic tape with welded edges. The inner metallized side is the cathode. Inside the tube there is gas under excess pressure.

At present, in accelerator experiments, coordinate detectors based on thin-walled drift tubes are widely used, for example, the SDC [1], TRT ATLAS [2], and COMPASS [3, 4] trackers. Detectors consist of a series of planes containing drift tubes tightly located to each other with a diameter usually from 4 mm to 10 mm and a length of ~ 40 cm [2, 5] to ~ 400 cm [1, 3, 4].

The level of technology.

Known methods for manufacturing drift tubes are described in [6, 8]. In these works, plastic tapes coated with metal [6] or metal and converting layers [8] are used for the manufacture of drift tubes. The technology for forming such tubes from a tape is similar to that described in [7]. In these cases, the tube is wound from one or more tapes on a cylindrical rod with fastening the edges with glue. The disadvantage of this design can be considered a long spiral seam. To reduce the scattering / absorption of the detected particles / radiation by the tube material and thereby reduce the parasitic effect on the processes under study, the tube should be made of the finest material, if possible. At the same time, the tube must withstand the working overpressure of the gas inside. Compared with the invention, the known tubes have a longer weld length, the strength of which is less than the area of the base material.

In addition, the known tubes have edges glued with a large overlap, which leads to an increase in the effective wall thickness of the tube.

Another embodiment of the manufacture of entire panels of drift tubes is described in [9]. In this case, a panel containing several tubes is glued from two preformed halves, each of which contains half of the tubes cut along a plane passing through their axis. Such a panel also contains large area flat adhesive seams between the tubes, which negatively affects the efficiency of the detector. In addition, the gas pressure inside the tube tends to delaminate, which reduces the reliability of the tube.

Closest to the proposed device (prototype) is a device for a plastic-coated metal pipe [10], including means for ultrasonic welding; feed reel with tape; means for forming a tape in a U-shaped profile; an annular die for forming a tube blank with overlapping edges and a cylindrical anvil.

The disadvantage of this device is that it is used for ultrasonic welding of metal pipes, then coated with plastic, and is not intended for welding pipes made of metal-plastic or plastic. In addition, in the manufacture of drift tubes with its help, it is impossible to obtain a tube with a long strong sealed seam and a smooth surface inside, since a long thin-walled tube cannot maintain its shape without excessive pressure inside, and the method of positioning the seam does not allow the inner surface to be made the tube is a smooth, non-distorting electric field inside the tube.

Disclosure of the invention.

The invention solves the problem of manufacturing drift tubes based on plastic of the smallest possible thickness, minimize the length and width of the weld and maximize the smoothness of the inner surface, and also solves the problem of increasing the strength of a sealed weld.

The technical problem in the present invention is solved in that the working body for ultrasonic welding is a sonotrode with a spherical working surface with the possibility of its being pressed against the anvil; the feeding reel is equipped with an adjustable belt tensioner; the tape is made of plastic-based material; the means for forming the tape into a U-shaped profile has an adjustment unit for accurately positioning the longitudinal edges of the tube blank relative to the sonotrode and the anvil; the die has means for accurately positioning it relative to the anvil; in addition, the device is equipped with a guide with the possibility of moving a carriage along it to draw a tube with a nozzle for supplying gas under excessive pressure to the welded part of the tube.

Distinctive features of the invention are:

- a sonotrode with a spherical working surface together with a cylindrical anvil form a welding point, thereby reducing the width of the weld. During welding, the sonotrode is firmly pressed against the anvil, thereby increasing the welding strength and improving the quality of the weld from the inner surface of the tube.

- the feeding bobbin with an adjustable belt tensioner together with the carriage for pulling the tube create tension of the tube blank along the axis of pulling, which allows you to perform a smooth high-quality seam of minimum length;

- the tape is made of a material based on plastic, which makes it possible to produce thin-walled drift tubes of minimum thickness with a hermetic weld;

- the tool for forming the tape into a U-shaped profile has an adjustment unit for accurately positioning the longitudinal edges of the tube blank relative to the sonotrode and the anvil, this allows you to combine the weld with the inner edge of the blank, thereby making the inner surface of the tube smooth along its entire length;

- a die with means for accurately positioning it relative to the anvil allows forming a tube blank so that the blank touches the anvil at the weld point, and in other places there is a guaranteed gap between them. This allows you to make high-quality smooth inner surface of the tube;

- the guide provides the direction of pulling the tube, due to this an even and smooth weld of the minimum length is formed;

- the carriage for pulling the tube provides a pulling force, which makes it possible sealed weld;

- the gas nozzle provides excessive pressure in the welded part of the tube to maintain its shape, thereby making the welding process possible, and also reduces and stabilizes the friction between the tube and the anvil, which improves the quality of the inner surface of the tube.

List of figures:

Figure 1 General view of the device, where:

1 - means for ultrasonic welding;

1a - sonotrode with a spherical working surface;

2 - feed reel with tape;

6 - adjustable belt tensioner;

3a is a roller as part of a tool for forming a tape in a U-shaped profile;

3b is an adjustment unit as a part of a means for forming a tape into a U-shaped profile;

4 - die with means for precise positioning;

5 - anvil;

7 - a guide;

8 - carriage;

9 - nozzle for supplying gas;

A is the direction of the force pressing the sonotrode;

In - the direction of the tube;

Figure 2 The relative location of the die and sonotrode in the context, where:

4 - die;

5 - anvil;

1a - sonotrode;

Figure 3 The mutual arrangement of the guide and the carriage with the nozzle in the context, where:

7 - a guide;

8 - carriage;

9 - nozzle;

C is the direction of gas flow into the welded part of the tube.

Figure 4 General view of the manufactured tube, where:

10 - weld.

Figure 5 is a Sectional view of the weld, where:

10a - weld with an increase. The lower inner surface of the seam of the tube is smooth, and on the upper non-working surface a small clearance is permissible.

A prototype of the proposed device for the manufacture of cylindrical tubes for gas-filled drift detectors of ionizing radiation. The device contains means for ultrasonic welding (1), which is an emitter of mechanical vibrations of sound frequency transmitted using a sonotrode with a spherical working surface (1a) to the welding point of the edges of the tube blank. The reel with tape (2) contains a supply of plastic tape that can be coated with metal. Adjustable belt tensioner (6) can be made as a friction clutch with constant friction. The tool for forming the tape in a U-shaped profile consists of a roller (3a) and adjustable stops (3b) for the edges of the tape. An annular die (4) for forming a U-shaped profile in the tube blank allows positioning the blank in a plane perpendicular to the direction of drawing. Around the cylindrical anvil (5), a tube blank is formed with overlapping edges, and the edges are welded on it with a sonotrode (1a). A carriage (8) moves along the guide (7), on which the end of the drawn tube is fixed. The carriage contains a nozzle (9) for supplying gas to the welded portion of the tube.

The device operates as follows. The reel with the tape (2) on the adjustable tensioner (6), the adjusting device (3b), the anvil (5), the die (4) and the sonotrode (1a) are pre-positioned along the axis of the tape extension, for example, using a laser beam. A die with means for precise positioning (4), for example, adjusting screws, is positioned relative to the anvil (5) so that the tube to be welded touches the anvil only at the weld point in the presence of gas under excessive pressure in the welded part of the tube. Using, for example, adjustable stops of the U-profile former (3b), the position of the edges to be welded is aligned with the contact point of the sonotrode to the anvil. The drawn tape is formed into a U-shaped profile, and then into the tube blank by a die (4). The ribbon blank stretched by the tensioner (6) and the pulling carriage (8) extends between the anvil and the sonotrode sphere pressed to it. Welding at the same time. Thus, the produced weld (10) fastens the edges of the strip blank overlap, attaching the inner edge of the blank to the inner surface of the tube over the entire length (10a).

Using the present invention, cylindrical tubes based on plastic are made for gas-filled drift ionizing radiation detectors with overlap welded edges. This makes it possible to obtain tubes of the smallest possible thickness, but of sufficient strength for operation at a working gas pressure inside the tube, since the weld is loaded with a shear-welded shear force; minimize the length and width of the weld, which also positively affects the efficiency of the detector; maximize the smoothness of the inner surface by eliminating the overhang of the edge along the entire length, which reduces the distortion of the electric field inside the tube.

Information sources

1. Y. Arai et al., Nucl. Instr. And meth. A381 (1996) 355-365.

2. ATLAS collaboration. ATLAS Inner Detector Technical Design Report, v. 1, CERN / LHCC / 97-16, 1997.

3. V.N. Bytchkov, M. Faessler, R. Geyer et al., Particles and Nuclei, Letters, 2002, No. 2 | 111 |, p. 64-73.

4. V.N. Bytchkov, N. Dedek, W. Dunnweber et al., Nucl. Instr. And meth. A556 (2006) 66-79.

5. I.V. Boguslavsky, V.N. Bychkov, K.S. Viryasov et al. Letters in ECHAYA, 2006, vol. 3, No. 3 (132), pp. 103-110.

6. BARINGER et al., Nucl. Instr. And meth. A254 (1987) 542-548.

7. Precision Paper Tube Company, Wheeling, Illinois, USA.

8. US Patent 7002159 Feb. 21, 2006. Jeffrey L. Lacy. Boron coated straw neutron detector.

9. US Patent 5071381 Dec. 10, 1991. Leonard Shieber. Process for the manufacture of straw tube drift chambers.

10. Patent RU 2076784 04/10/1997 Ishaq Barnoash. Device for manufacturing plastic coated metal pipe.

Claims (1)

A device for manufacturing cylindrical tubes for gas-filled drift detectors of ionizing radiation, comprising ultrasonic welding means, a feeding reel with a tape made of plastic-based material, means for forming a tape in a U-shaped profile, an annular die for forming a tube blank with overlapping edges and cylindrical anvil, characterized in that the working body of the means for ultrasonic welding is a sonotrode with a spherical working surface, is installed which can be pressed against the anvil, the feeding reel is equipped with an adjustable belt tensioner, the means for forming the tape into a U-shaped profile has an adjustment unit for accurately positioning the longitudinal edges of the tube blank relative to the sonotrode and the anvil, and the die has means for accurately positioning it relative to the anvil, while the device is equipped with a carriage for fixing on it the end of the tube mounted with the possibility of its movement along the guide for pulling the tube and equipped with oslom for supplying gas under excessive pressure to the welded part of the tube.

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